UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Vapor-liquid equilibria at elevated temperatures and pressures Whittle, Donald James 1962

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1962_A1 W4 V2.pdf [ 10.67MB ]
Metadata
JSON: 831-1.0059061.json
JSON-LD: 831-1.0059061-ld.json
RDF/XML (Pretty): 831-1.0059061-rdf.xml
RDF/JSON: 831-1.0059061-rdf.json
Turtle: 831-1.0059061-turtle.txt
N-Triples: 831-1.0059061-rdf-ntriples.txt
Original Record: 831-1.0059061-source.json
Full Text
831-1.0059061-fulltext.txt
Citation
831-1.0059061.ris

Full Text

VAPOR-LIQUID EQUILIBRIA AT ELEVATED TEMPERATURES AND PRESSURES by DONALD JAMES WHITTLE B.A.Sc, University of B r i t i s h Columbia, 1956 M.A.Sc, University of B r i t i s h Columbia, 1958  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF Ph.D. i n the Department of Chemical Engineering  We accept t h i s thesis as conforming to the required standard i  THE UNIVERSITY OF BRITISH COLUMBIA March, 1962  In presenting  this thesis i n partial fulfilment of  the r e q u i r e m e n t s f o r a n advanced degree a t t h e U n i v e r s i t y o f B r i t i s h Columbia, I agree t h a t t h e L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . for extensive  I f u r t h e r agree t h a t p e r m i s s i o n  c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y purposes may be  g r a n t e d by t h e Head o f my Department o r by h i s  representatives.  I t i s understood t h a t copying o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n  Department o f The U n i v e r s i t y o f B r i t i s h Vancouver 3 , Canada. Date  TrU^Jl  /(  %  /9CL  Columbia,  permission.  The University of B r i t i s h Columbia FACULTY OF GRADUATE STUDIES  PROGRAMME OF THE FINAL ORAL EXAMINATION FOR THE DEGREE OF DOCTOR OF PHILOSOPHY of DONALD JAMES WHITTLE  B.A.Sc. M.A.Sc.  University of B r i t i s h Columbia University of B r i t i s h Columbia  THURSDAY, MARCH 15th,  1962, at 2:30 P.M.  IN ROOM 207, CHEMICAL ENGINEERING BUILDING  COMMITTEE IN CHARGE Chairman W.A. S.D. H.M. B.A.  BRYCE CAVERS DAGGETT, JR. DUNELL  F.H. Soward J.S. FORSYTH B.H. LEVELTON D.S. SCOTTP.L. SILVESTON  External Examiner: Benjamin C.-Y. LU University of Ottawa, Canada.  VAPOR-LIQUID EQUILIBRIA AT ELEVATED AND  TEMPERATURES  GRADUATE STUDIES  PRESSURES F i e l d of Study: ABSTRACT ,  A modified version of an apparatus by Sage and Lacey (Trans. A.I.M.E., 174: 102, 1948) for phase equilibrium measurements at elevated temperatures and pressures has been designed and b u i l t . Assembly and d e t a i l drawings of the apparatus, and a detailed description for i t s use have been included. The vapor pressure of methanol has been measured at temperatures from 100°C. to 225°C, and the vapor pressures of benzene and toluene have been measured at temperatures from 125°C. to 250°C, Good agreement with l i t e r a t u r e values was found for the vapor pressures of each of these materials. Vapor-liquid equilibrium composition and pressure data have been measured for the benzene-toluene system at 200°C. and compared to values reported for this system by v . Huhn (Forsch. Geb, Ingenieurw., A2: 129, 1931) and by Griswold, Andres, and Klein (Trans. A.I.Ch.E., 37: 223, 1943). A c t i v i t y c o e f f i c i e n t s calculated for the l i q u i d phase from the experimental data show that the l i q u i d mixture forms a Lewis and Randall perfect solution. Isothermal vapor-liquid equilibrium composition and pressure data for the methanol-toluene system have been measured at 25-degree intervals from 125°C. to 250°C. An azeotrope was found for the system at temperatures of 125°C, 150°C. and 175°C., and i t was estimated that this azeotrope disappears at 193.4°C. A c t i v i t y c o e f f i c i e n t s have been calculated from the experimental data using several approximate methods, and tested for thermodynamic consistency using the test proposed by Redlich and Kister (Ind. Eng. Chem., 40: 345, 1948). Coefficients calculated using the method proposed by Black (Ind. Eng. Chem., 50: 391, 1958) were the only ones which showed good thermodynamic consistency when tested i n this way, and these have been correlated with a Redlich and Kister four-constant equation.  Chemical Engineering  Chemical Engineering Thermodynamics I n d u s t r i a l Kinetics and Catalysis Momentum, Heat and Mass Transfer Solvent Extraction Distillation F l u i d and P a r t i c l e Dynamics Process Heat Transfer Other Studies Applied F l u i d Mechanics Theory and Application of D i f f e r e n t i a l Equations S t a t i s t i c a l Theory of Matter Physical Inorganic Chemistry  L.W. Shemilt D.S. Scott N. Epstein S.D. Cavers J.S. Forsyth N. Epstein N. Epstein  A.W. T. W. C. J.  Marris Hull Opechowsk Reid, Halpern  ABSTRACT  i i  A m o d i f i e d v e r s i o n o f a n a p p a r a t u s b y S a g e a n d Lacey"'" f o r p h a s e e q u i l i b r i u m measurements d e s i g n e d and b u i l t .  a t e l e v a t e d t e m p e r a t u r e s and p r e s s u r e s has been  Assembly and d e t a i l  drawings o f t h e a p p a r a t u s , and a  d e t a i l e d d e s c r i p t i o n f o r i t s use have been The v a p o r p r e s s u r e o f m e t h a n o l f r o m 100  C  t o 225  C,  included.  has been measured a t temperatures  and t h e v a p o r p r e s s u r e s o f benzene and o f t o l u e n e have  been measured a t temperatures from  125°C. t o 250°C.  Good a g r e e m e n t w i t h  l i t e r a t u r e v a l u e s was f o u n d f o r t h e v a p o r p r e s s u r e s o f e a c h o f t h e s e m a t e r i a l s . V a p o r - l i q u i d e q u i l i b r i u m c o m p o s i t i o n and p r e s s u r e d a t a have b e e n measured f o r the benzene-toluene reported f o r this  system a t  s y s t e m b y v . Huhn  2  200°C a n d c o m p a r e d t o v a l u e s  3  and b y G r i s w o l d , Andres, and K l e i n .  A c t i v i t y c o e f f i c i e n t s c a l c u l a t e d f o r t h e l i q u i d phase from the e x p e r i m e n t a l  k d a t a show t h a t t h e l i q u i d m i x t u r e f o r m s a L e w i s a n d R a n d a l l  perfect  solution.  I s o t h e r m a l v a p o r - l i q u i d e q u i l i b r i u m c o m p o s i t i o n and p r e s s u r e d a t a f o r t h e m e t h a n o l - t o l u e n e s y s t e m h a v e b e e n m e a s u r e d a t 25-degree from of  125^C. t o 250 C.  125°, 150°,  a t 193.  4°C  data using  and  intervals  An a z e o t r o p e was f o u n d f o r t h e s y s t e m a t t e m p e r a t u r e s  175°C, a n d i t was e s t i m a t e d t h a t t h i s a z e o t r o p e d i s a p p e a r s  A c t i v i t y c o e f f i c i e n t s have been c a l c u l a t e d from t h e e x p e r i m e n t a l s e v e r a l approximate methods, and t e s t e d f o r thermodynamic  c o n s i s t e n c y u s i n g t h e t e s t proposed by R e d l i c h and K i s t e r  5  .  Coefficients  6 c a l c u l a t e d u s i n g t h e m e t h o d p r o p o s e d b y B l a c k w e r e t h e o n l y o n e s w h i c h showed g o o d t h e r m o d y n a m i c c o n s i s t e n c y when t e s t e d i n t h i s way, a n d t h e s e h a v e b e e n  5 c o r r e l a t e d w i t h a R e d l i c h and K i s t e r  four-constant equation.  The f a i l u r e  of  a c t i v i t y c o e f f i c i e n t s c a l c u l a t e d b y approximate methods o t h e r t h a n B l a c k ' s t o show g o o d t h e r m o d y n a m i c c o n s i s t e n c y i n d i c a t e s t h a t t h e s o l u t i o n t h e o r i e s o n w h i c h t h e s e methods a r e b a s e d a r e i n v a l i d f o r a n o n - i d e a l system o f t h e t y p e  studied.  TABLE OF CONTENTS  iii  INTRODUCTION Importance of Vapor-liquid Equilibrium Data  1  Methods of Measuring Vapor-liquid E q u i l i b r i a Under Pressure  1  Methods of Testing Vapor-liquid Equilibrium Data  k  Calculation of Fugacities and A c t i v i t y C o e f f i c i e n t s from Experimental Data by Exact Methods  6  Calculation of Fugacities and A c t i v i t y C o e f f i c i e n t s from Experimental Data by, Approximate Methods Systems Studied and Type °f Equipment Used  8 11  APPARATUS AND PROCEDURE - Apparatus Introduction  13  General Arrangement of Apparatus  13  Bath Temperature Control and Measurement  15  Pressure Measurement  l6  Samples of Coexisting Phases  17  APPARATUS AND PROCEDURE - Experimental Procedure Preliminary Steps  17  Introduction of Material to C e l l  18  Preparation f o r Sampling  19  Measurements  19  Analysis  20  MATERIALS Benzene  21  Toluene  21  Methanol  21  VAPOR PRESSURE MEASUREMENTS - Benzene Previous Work Results and Discussion  23 . 2k  iv  VAPOR PRESSURE MEASUREMENTS - Toluene Previous Work  27  Results and Discussion  28  VAPOR PRESSURE MEASUREMENTS - Methanol Previous Work  33  Results and Discussion  3^  BENZENE-TOLUENE SYSTEM Previous Measurements  39  Results  hi  Calculation of A c t i v i t y C o e f f i c i e n t s  hi  Discussion  h9  METHANOL-TOLUENE SYSTEM 'Previous Measurements  5h  Results  55  Calculation of A c t i v i t y C o e f f i c i e n t s  71  1.  A c t i v i t y c o e f f i c i e n t s i n terms of deviations from Raoult s law  75  A c t i v i t y c o e f f i c i e n t s by the Lewis and Randall rule a) Generalized fugacity chart of Gamson and Watson  76 76  1  2.  b) Generalized equation of state of Black 3.  77  Generalized equation of state of Hirschfelder et a l and fugacity equation of Joffe  78  h.  Generalized equation of state of Redlich and Kwong  79  5-  Generalized equation of state of Black  80  Thermodynamic Consistency Check of Experimental Data  82  Correlation of A c t i v i t y C o e f f i c i e n t s Obtained from the Equations of Black  83  Discussion Presentation of experimental data  9^-  Azeotrope  9^  V  A c t i v i t y c o e f f i c i e n t calculations  96  Cause of apparent inconsistencies i n a c t i v i t y coefficients  calculated by Black's methodr  Activity coefficient correlation  100 101  CONCLUSIONS AND RECOMMENDATIONS Vapor Pressure Measurements  103  Benzene-toluene System  103  Methanol-toluene System Recommendations f o r Future Work  10k 105  TABLE OF SYMBOLS  107  LITERATURE CITED  111  APPENDIX I - APPARATUS Equilibrium C e l l  I-l  Volume Compensating C e l l  I-l  - Relative Location of the C e l l s and Method of Clamping  1-2  Measuring Head  1-3  Measuring Head Bridge  1-5  Measuring Head Rod Assembly  1-7  Measuring Head Rod Seal  1-7  Measuring Head Rod Drive  1-8  Measuring Head Rod Drive C i r c u i t  I-10  Bomb Tubing Connection  1-12  Equilibrium C e l l S t i r r e r  1-12  Sampling Tube Assembly  I-lk  Constant Temperature Bath  1-15  Temperature Control of the Bath  1-17  Temperature Measurement  1-19  Measurement of Pressure  1-23  vi Associated Glassware  1-28  APPENDIX II - DETAILS OF METHOD Cleaning of Equipment  II-l  Introduction of Mercury and Definition of Gauge Zero  II-l  Conversion of Gauge Reading to Absolute Pressure in the Equilibrium Cell  II-2  1. Correction for atmospheric pressure  II-3  2. Correction for variation of mercury level inside the c e l l 3- Correction for change of mercury * density with  II-3  temperature  II-3  Introduction of Materials  II-k  Preparation for Measurements  II-6  Measurements and Taking of Samples  II-8  Further Measurements  II-9  Temperature Limits for the Use of the Equipment  II-9  APPENDIX III - CHROMATOGRAPHIC ANALYSIS OF PURIFIED METHANOL  III-l  APPENDIX TV - ANALYSIS OF BENZENE-TOLUENE AND METHANOL-TOLUENE MIXTURES Benzene-toluene Mixtures  IV-1  Toluene-methanol Mixtures  IV-2  APPENDIX V - PURIFICATION OF MERCURY APPENDIX VI - TABLES OF MEASURED AND CALCULATED DATA FOR METHANOL-TOLUENE SYSTEM APPENDIX VII - PROCEDURES USED TO PURIFY BENZENE, TOLUENE, AND  V-l VI-1  METHANOL FOR VAPOR PRESSURE MEASUREMENTS Benzene  VII-1  Toluene  VII-2  Methanol  VII-3  vii  LIST OF FIGURES  Figure  Page  1.  General Arrangement of Apparatus  Ik  2.  Vapor Pressure of Benzene  26  '3-  Vapor Pressure of Toluene  31  k.  Vapor Pressure of Methanol  37  5-  Vapor-liquid Equilibrium "x - y" Composition Diagram f o r BenzEne-toluene System at 200  C.  kk  6.  Vapor-liquid Equilibrium Pressure Composition Plot f o r Benzene-toluene System at 200 C.  k*?  7-  Vapor-liquid Equilibrium "x-y" Composition Diagram f o r Benzene-toluene System at 200° C  50  Vapor-liquid Equilibrium Pressure Composition Diagram f o r Benzene-toluene System at 200° C  51  Vapor-liquid Equilibrium "x-y" Composition Diagram for Methanol-toluene System at 125° C.  56  Vapor-liquid Equilibrium Pressure Composition Diagram f o r Methanol-toluene System at 125° C  57  Vapor-liquid Equilibrium "x-y" Composition Diagram f o r Methanol-toluene System at I5O C  58  Vapor-liquid Equilibrium Pressure Composition Diagram f o r Methanol-toluene System at I5O C  59  Vapor-liquid Equilibrium "x-y" Composition Diagram f o r Methanol-toluene System at 175° C  60  Ik.  Vapor-liquid Equilibrium Pressure Composition Diagram f o r Methanol-toluene System at 175° C.  6l  15•  Vapor-liquid Equilibrium "x-y" Composition Diagram f o r Methanol-toluene System at 200° C.  62  Vapor-liquid Equilibrium Pressure Composition Diagram f o r Methanol-toluene System at 200° C.  63  Vapor-liquid Equilibrium ."x-y" Composition Diagram f o r Methanol-toluene System at 225° C.  6k  Vapor-liquid Equilibrium Pressure Composition Diagram f o r Methanol-toluene System at 225° C  65  Vapor-liquid Equilibrium "x-y" Composition Diagram for Methanol-toluene System at 250° C.  66  8. 910. 11.  0  12.  0  13-  16.  1718.  19-  viii Figure  20.  Page Vapor-liquid Equilibrium Pressure Composition Diagram f o r Methanol-toluene System at 250° C.  67  Equilibrium Ratio as a Function of the Logarithm of the Pressure f o r Methanol  68  Equilibrium Ratio as a Function of the Logarithm of the Pressure f o r Toluene  69  23-  Azeotrope Composition  72  2k.  Pressure-temperature Diagram f o r Methanol-toluene Azeotrope  73  25-  Ratio of A c t i v i t y C o e f f i c i e n t s i n the System Methanol-toluene at 125° C.  81+  26.  Ratio of A c t i v i t y C o e f f i c i e n t s i n the System Methanol-toluene at 150° C  85  27-  Ratio of A c t i v i t y C o e f f i c i e n t s i n the System Methanol-toluene at 175° C  86  28.  Ratio of A c t i v i t y C o e f f i c i e n t s i n the System Methanol-toluene at 200° C-  87  29-  Ratio of A c t i v i t y C o e f f i c i e n t s i n the System Methanol-toluene at 225 C  88  30.  Ratio of A c t i v i t y C o e f f i c i e n t s i n the System Methanol-toluene at 125° C.  89  Ratio of A c t i v i t y C o e f f i c i e n t s i n the System Methanol-toluene at I5O C-  90  Ratio of A c t i v i t y C o e f f i c i e n t s i n the System Methanol-toluene at 175° C.  91  21. 22.  31-  0  32.  1-6  I-l.  Nichrome Detecting Wire Bridge  1-2.  Measuring Head Drive C i r c u i t  I-ll  1-3-  Temperature  I-18  I-k.  Thermocouple Position f o r Temperature  1-5-  Transfer  1-6.  Intermediate Storage Flask and Mercury Storage Flask  1-30  1-7-  Sample C o l l e c t i o n Tubes  1-32  1-8.  Assembly of Equilibrium  Control  Circuit Survey  1-21 1-29  Flasks  Cell  I-3U  ix Figure 1-9-  Page Assembly of Equilibrium C e l l  I-35  I-10.  Assembly of S t i r r e r and Measuring Head  I-36  1-11.  Assembly of Lower C e l l , Reduction Gear and Universal Joint  I-37  1-12.  Assembly of Measuring Head Rod Driving Equipment  I-38  1-13.  Part Number 1  I-39  1-14.  Parts Number 5, 6, and 7  1-40  1-15.  Parts Number 8 and ^  I-l6.  Parts Number 2, 3, and 4  1-42  1-17-  Parts Number 10, 11, 12, and 13  1-43  1-18.  Parts Number 16 to 23  1-44  1-19.  Parts Number 25 to 31  1-45  1-20.  Parts Number 23, 36, 62, and 68  1-46  1-21.  Parts Number 40 and 4 l  1-47  1-22.  Parts Number 42 and 43  1-48  I-23.  Parts Number 44, 45, 46, and 47  1-49  1-24.  Parts Number 50, 51, 52, and 53  I-50  1-25.  Parts Number 84, 88, 93, and 94  1-51  1-26.  Parts Number 85, 86, 89, and 91  1-52  1-27.  Parts Number 49, 75, 77, and 78  I-53  IV-1.  Chromatographic C a l i b r a t i o n f o r Benzene-toluene System  IV-5  IV-2. IV-3-  Chromatographic C a l i b r a t i o n f o r Benzene-toluene System Refractive Index C a l i b r a t i o n Curve f o r the Methanoltoluene System  IV-6  I-4l  IV-9  LIST OF TABLES  x  Table  Page  1.  Vapor P r e s s u r e o f Benzene  25  2.  Vapor P r e s s u r e o f Toluene  29  3-  Measured and C a l c u l a t e d  30  k.  Vapor P r e s s u r e o f Methanol  35  5-  Measured Vapor P r e s s u r e o f Methanol  36  6.  Vapor-liquid at  7.  Vapor-liquid at  8. 9-  2 0 0 °  200°  28. 29-  E q u i l i b r i a o f Benzene-toluene  System 1+0  C  E q u i l i b r i a o f Benzene-toluene C  System 1+2  1  V a p o r - l i q u i d E q u i l i b r i a o f t h e Benzene-toluene a t 2 0 0 ° C as M e a s u r e d . i n t h i s P r o j e c t A c t i v i t y C o e f f i c i e n t s f o r Benzene-toluene 2 0 0 °  17-  Vapor P r e s s u r e s o f Toluene  System 1+3  System a t 1+8  C.  C a l c u l a t e d and Measured V a l u e s f o r t h e M e t h a n o l - t o l u e n e Azeotrope  7 0  V a l u e s o f t h e I n t e g r a l (\r. <^/Y 6*-, t o l u e n e System •* '  9 2  t  Coefficients of Redlich  f o r Methanol-  and K i s t e r C o r r e l a t i o n f o r 9 5  M e t h a n o l - t o l u e n e System  1 - 2 0  I-l.  R e s u l t s o f Temperature Survey o f E q u i l i b r i u m  1-2.  C a l i b r a t i o n Supplied by Manufacturer f o r Heise Pressure Gauge Number 2 1 8 7 0 ' C a l i b r a t i o n Determined U s i n g t h e B a r n e t t Dead Weight  1-3-  Cell  T e s t e r Model Number MKT f o r Gauge Number 1-1+. 1-5-  2187O  C a l i b r a t i o n S u p p l i e d by M a n u f a c t u r e r f o r H e i s e P r e s s u r e Gauge Number 2 1 8 6 9  I-21+  1-25  1-26  C a l i b r a t i o n Determined U s i n g t h e B a r n e t t Dead Weight T e s t e r Model Number MKT f o r Gauge Number  2186/9  1-27  IV-1.  Chromatographic  IV-2.  A c c u r a c y o f C a l i b r a t i o n o f Chromatograph  IV-1+  IV-3-  T y p i c a l Refractometer C a l i b r a t i o n f o r Methanol-toluene System a t 2 0 ° C  IV-6  Calibrations  f o r Benzene-toluene  System  IV-3  xi Table 10. 11. 12.  13.  Ik. 15• l6.  Page Vapor-liquid Equilibrium Data f o r the Methanol-toluene System at a Pressure of one Atmosphere  VI-1  Vapor-liquid Equilibrium Data f o r the Methanol-toluene System at 125° C.  VI-2  Vapor-liquid Equilibrium Data f o r the Methanol-toluene System at"150° c .  VI-3  Vapor-liquid Equilibrium Data f o r the Methanol-toluene System at 175° c .  Yl-k  Vapor-liquid Equilibrium Data f o r the Methanol-toluene System at 200° C  VI-5  Vapor-liquid Equilibrium Data f o r the Methanol-toluene System at 225° C.  VI-6  Vapor-liquid Equilibrium Data f o r the Methanol-toluene System at 250° C.  VI-7  18.  A c t i v i t y C o e f f i c i e n t s f o r Methanol at 125° C.  VI-8  19.  A c t i v i t y C o e f f i c i e n t s f o r Toluene at 125° C  VI-9 .  20.  A c t i v i t y C o e f f i c i e n t s f o r Methanol at I5O c .  VI-10  21.  A c t i v i t y C o e f f i c i e n t s f o r Toluene at 150 C.  VI-U  22.  A c t i v i t y C o e f f i c i e n t s f o r Methanol at 175° C.  VI-12  23.  A c t i v i t y C o e f f i c i e n t s f o r Toluene at 175° c .  VI-13  2k.  Natural Logarithm of the Ratio of the A c t i v i t y C o e f f i c i e n t s f o r Methanol and Toluene at 125° C  VI-14  Natural Logarithm of the Ratio of the A c t i v i t y C o e f f i c i e n t s f o r Methanol and Toluene at 150° C  VI-15  Natural Logarithm of the Ratio of the A c t i v i t y C o e f f i c i e n t s f o r Methanol and Toluene at 175° C  VI-l6  2526. 27-  0  0  Natural Logarithm of the Ratio of the A c t i v i t y C o e f f i c i e n t s f o r Methanol and Toluene Calculated by the Method of Black f o r Temperatures of 200°  and 225° C. 30.  Comparison of A c t i v i t y C o e f f i c i e n t s Calculated from Equation of Black and from Redlich and K i s t e r Correlation f o r Methanol and Toluene at 125° C  VI-17  VI-18  Comparison of A c t i v i t y C o e f f i c i e n t s Calculated from Equation of Black and from Redlich and K i s t e r Correlation f o r Methanol and Toluene at 1 5 0 ° rj. Comparison of A c t i v i t y C o e f f i c i e n t s Calculated from Equation of Black and from Redlich and K i s t e r Correlation f o r Methanol and Toluene at 1 7 5 ° C. Comparison of A c t i v i t y C o e f f i c i e n t s Calculated from Equation of Black and from Redlich and Kister Correlation f o r Methanol and Toluene at 2 0 0 ° rj. Comparison of A c t i v i t y C o e f f i c i e n t s Calculated from Equation of Black and from Redlich and K i s t e r Correlation f o r Methanol and Toluene at 2 2 5 ° C.  ACKNOWLEDGEMENT  -xiii  The author wishes to acknowledge the assistance and advice given by Dr. L. W. Shemilt, under whose d i r e c t i o n t h i s project was c a r r i e d out, and to thank Dr. Shemilt f o r h i s constant encouragement.  He wishes to acknowledge,  as well, the help received from Dr. D. S- Scott i n Dr. Shemilt's absence. The author i s also deeply indebted to Dr. J . S. Forsyth/ f o r h i s extensive and very p r a c t i c a l help i n solving the many problems associated with the design and construction of the equipment used i n t h i s work. The Ph.D  committee which supervised the work reported i n t h i s  thesis consisted of Dr. L. W. Shemilt, Dr. D. S. Scott, Dr. J . S. Forsyth, Dr. H. M. Daggett, and Dr. N- Epstein.  This committee was chaired by Dr. L.  W. Shemilt and, i n h i s absence, by Dr. D. S. Scott. The drawings and graphs included i n t h i s thesis have been copied from tracings prepared by,the author's wife, Mrs. D. Whittle. Personal assistance has been given to the author during the course of t h i s work by The Standard O i l Company of B r i t i s h Columbia i n the form of a Standard O i l Fellowship, by Canadian Industries Limited i n the form of a C  I. L. Fellowship, and by the National Research Council of Canada i n the  form of an N. R. C  Studentship.  F i n a n c i a l support f o r the work c a r r i e d out  in t h i s project came from the National Research Council of Canada through a grant given to the Department of Chemical Engineering at t h i s University.  INTRODUCTION  1.  Importance of Vapor-Liquid Equilibrium Data  When a l i q u i d mixture of two or more components i s p a r t i a l l y vaporized, the composition of the vapor produced i s normally d i f f e r e n t from that of the l i q u i d i t leaves.  I t i s t h i s change i n composition with change  i n phase that forms the basis of such separation processes as d i s t i l l a t i o n and absorption, and a quantitative knowledge of the change i s therefore e s s e n t i a l f o r the a n a l y t i c a l treatment of these processes. Data descriptive of the composition of the l i q u i d and vapor phases, as a function of temperature and pressure, when the two phases are i n equilibrium with respect to the movement of the molecules of each component from one phase to the other, are used as the basis of t h i s a n a l y t i c a l treatment.  The importance of the a v a i l i b i l i t y of such  vapor-liquid equilibrium data i s obvious. The accurate measurement of solution properties requires very c a r e f u l work, and because i t i s c l e a r l y impossible to investigate a l l  systems  at a l l conditions of temperature and pressure, many attempts have been made to develop a solution theory by means of which such data may be predicted from the properties of the pure components or from a l i m i t e d amount of data on solutions. The t e s t i n g of such theories required extensive tabulations of thermodynamic data f o r types of systems of no immediate i n d u s t r i a l importance and f o r systems under conditions of temperature and pressure not normally encountered i n industrial practice.  The measurement of data to f i l l t h i s need has become an  important f i e l d of study. Methods of Measuring Vapor-Liquid E q u i l i b r i a under Pressure  Many methods have been used to experimentally determine vapor-liquid  7 equilibria-Robinson and G i l l i l a n d following headings:  have c l a s s i f i e d these methods under the  2.  a) b) c) d) e)  Dynamic Flow Method Dynamic D i s t i l l a t i o n Method C i r c u l a t i o n Method Continuous D i s t i l l a t i o n Method Dew-and-Bubble-Point Method  f ) Bomb Method Of these s i x methods, only the l a s t four are important f o r measurements at pressures above atmospheric, and therefore only these four are discussed below. With the c i r c u l a t i o n method, the mixture to be studied i s placed i n an evacuated chamber.  The vapor i s c o l l e c t e d from above the l i q u i d and  c i r c u l a t e d back through the l i q u i d u n t i l the composition of both phases becomes constant.  Although the method i s b a s i c a l l y simple, several precautions  have to be taken i n order to obtain accurate r e s u l t s .  The entire system must be  leak-free to prevent the progressive loss of material and the r e s u l t i n g progressive change i n equilibrium properties.  The t o t a l quantity of each phase  must remain constant,and therefore the apparatus must be c a r e f u l l y thermostated, and the pump used to c i r c u l a t e the vapor must have a very small displacement. Since the pressure at the bottom of the l i q u i d phase, where the vapor enters, is d i f f e r e n t from that at the top of the phase, where the vapor leaves, the equilibrium composition i s also d i f f e r e n t at the two l e v e l s .  This change i n  equilibrium composition with pressure can be important i n the c r i t i c a l region.  Q The c i r c u l a t i o n method has "been successfully used by Aroyan and Katz pressures up to  8000 pounds  at  per square inch.  The continuous d i s t i l l a t i o n method i s a less accurate but simpler form of measurement.  The vapor i s c o l l e c t e d from above the b o i l i n g l i q u i d , condensed,  and returned to the s t i l l as a l i q u i d .  The method suffers from two disadvantages:  there i s some doubt as to whether or not a b o i l i n g l i q u i d produces an equilibrium vapor, and since the condensed vapor returned to the s t i l l has a d i f f e r e n t composition than the s t i l l l i q u i d , the two must be thoroughly mixed before any is vaporized.  These d i f f i c u l t i e s can be minimized by vaporizing the condensate  3before i t i s returned to the s t i l l , but care must be taken that a l l of the condensate i s vaporized and that none of i t i s super heated.  Measurements to  1000 pounds per square inch have been made with continuous d i s t i l l a t i o n equipment  3 by Griswold et a l . With the dew-and-bubble-point method, a vessel of variable volume i s f i r s t evacuated and then f i l l e d with a sample of known composition.  The  volume of the c e l l i s then varied i n order to obtain the dew and bubble points as a function of pressure at constant temperature.  These two points are  determined either by observation or by p l o t t i n g the pressure-volume  isotherms.  |  Equilibrium data are obtained from the i n t e r s e c t i o n of dew-and-bubble-point curves p l o t t e d as l i n e s of constant composition on a temperature-pressure diagram.  While extensive use has been made of t h i s method f o r the deter-  mination of vapor-liquid equilibrium data at elevated pressures, the method suffers from three disadvantages.  Very pure material must be used and i n  p a r t i c u l a r i t must be free of permanent gases.  Under c e r t a i n conditions, the  dew and bubble points are not sharply defined.  Probably the most serious  l i m i t a t i o n of the-method i s that i t i s r e s t r i c t e d to the study of binary systems. Kay and co-workers ^'  "  L1  have used t h i s method with a v i s u a l type of apparatus.  12 Sage and Lacey  have used a non-visual type at pressures as high as 10,000  pounds per square inch. In the bomb method,a sample i s placed i n an evacuated vessel, and the vessel i s then agitated at constant temperature between the l i q u i d and vapor phases. samples of each are taken.  u n t i l equilibrium i s obtained  Once the two phases are at equilibrium,  Often the samples are displaced with an equal  volume of an inert material such as mercury to prevent a change i n the e q u i l i brium properties while sampling.  Although accurate r e s u l t s are possible with  t h i s method, care must be used i n order to obtain them.  Any trace of l i q u i d  i n the vapor sample w i l l lead to serious errors i n the vapor composition under most conditions because of the r e l a t i v e densities of the two phases. Lacey ^ have used t h i s method to measure vapor-liquid e q u i l i b r i a  Sage and  at pressures  as high as 10,000 pounds per square inch. Of the four methods discussed above, the l a s t two, the s t a t i c methods, have been used f o r the majority of the measurements reported at pressures s i g n i f i c a n t l y above atmospheric.  A detailed review of equipment used with  these two methods,and a shorter description of equipment used f o r the other methods was given e a r l i e r by the author.  J  Methods of Testing Vapor-Liquid Equilibrium Data The state of a single phase, apart from i t s size, can be described by the set of intensive properties consisting of the temperature, chemical p o t e n t i a l of each component. ,"D" of a "C" component mixture  Since the number of degrees of freedom  with'Vphases i s  given by the phase rule ^  D + N = C + 2  independent.  as  (l)  the number of degrees of freedom of a single phase i s "C + 1". variables, temperature,  pressure and  The "C + 2"  pressure and chemical p o t e n t i a l cannot therefore a l l be  The relationship between these quantities, the derivation of which 15  i s given i n most standard texts on thermodynamics, e.g. Guggenheim  , i s known  as the Gibbs-Duhem equation and may be written as SdT-VdP+Sxi 1/^=0  (2)  The ;Gibbs-Duhem equation, or relationships derived from.it, i s used as the basis of a l l thermodynamic consistency checks of vapor-liquid equilibrium data.  Van Ness ^  has rearranged equation (2) using standard thermodynamic  r e l a t i o n s to a more convenient form f o r the 'testing of experimental data. terms of f u g a c i t i e s :  In  -^ dP T  +  i^H,dT-Z:x dlnf L  (3)  t  or i n terms of a c t i v i t i e s ^ d P  - f±,dT =  * dL*  Z  L  (U)  L  where A V and AH are the change of volume and change of enthalpy of mixing per mole of solution formed. Carlson and Colburn  IT  and more recently E l l i s and Bourne  reviewed the methods of testing vapor-liquid equilibrium data. commonly used tests may be divided into two groups:  1 ft  have  The most  the slope tests and the  area tests. The slope test has been used f o r many years and i s discussed i n most 19 standard texts on solution thermodynamics - e.g. Dodge  . Under conditions of  constant temperature and pressure equations (3) and (k) may be written as 1  I  x- d k - f =0  ( 5 )  * d\o  ( 6 )  t  o  L  or f o r a binary solution dint'.  X ,  ~d^r  _  d "*!  " ^  "a^r  1  (\ 7  ( 8 )  Although f o r a binary solution the data cannot be obtained with both temperature and pressure held constant, f o r many systems under isothermal conditions the e f f e c t of pressure changes can be ignored, and equations  (7)  and ( 8 ) can be used to check such isothermal data. The slope test has the advantage that the consistency of the data can be tested at every composition, but i t suffers from the serious disadvantage that i t i s d i f f i c u l t to measure slopes accurately and thus that the  u n c e r t a i n t y i n t h e s l o p e measurements i s o f t e n as g r e a t r a s t h e i n c o n s i s t encies i n the data. The o r i g i n a l e q u a t i o n s f o r t h e auea t e s t were d e r i v e d b y H e r i n g t o n C o u l s o n and H e r i n g t o n  21  , and R e d l i c h and K i s t e r  g e n e r a l i z e d b y Van Ness  R e d l i c h and K i s t e r  y  .  ,  The e q u a t i o n s have been  to give  whereZ^F^ i s t h e e x c e s s f r e e energy o f m i x i n g . c o n s t a n t temperature  S  20  For.binary solutions at  and p r e s s u r e , e q u a t i o n (9) reduces t o t h e f a m i l i a r equation.  In  =O  (|0)  18  E l l i s and Bourne  recommend t h e a r e a t e s t as t h e b e s t method f o r  checking the consistency of isothermal v a p o r - l i q u i d e q u i l i b r i u m data.  I t does  s u f f e r , however, from t h e d i s a d v a n t a g e t h a t a p o i n t check o f t h e d a t a i s n o t obtained. C a l c u l a t i o n o f F u g a c i t i e s and A c t i v i t y C o e f f i c i e n t s from E x p e r i m e n t a l Data b y E x a c t Methods 22  The f u g a c i t y o f a p u r e substance can be d e f i n e d by the r e l a t i o n s h i p  [RTln-£* J ( V - ^ ) d P ] 0  T  and t h e f u g a c i t y can t h e r e f o r e be e v a l u a t e d from (PVT) d a t a f o r t h e substance.  (VO pressure-volume-temperature  E q u a t i o n ( l l ) as w r i t t e n above i s g e n e r a l l y  r e s t r i c t e d t o t h e e v a l u a t i o n o f f u g a c i t i e s o f substances i n t h e v a p o r  state.  The e q u a t i o n i s d i f f i c u l t t o e v a l u a t e f o r l i q u i d s s i n c e t h e i n t e g r a l c o v e r s  the p r e s s u r e range from t h e h i g h l y a t t e n u a t e d gas s t a t e as t h e p r e s s u r e approaches z e r O j t o t h e system p r e s s u r e where t h e substance e x i s t s as a l i q u i d .  The  7fugacity of a l i q u i d i s generally evaluated instead i n two parts.  The fugacity  of the saturated vapor i s f i r s t calculated, and thenjmaking use of the f a c t that at saturation the l i q u i d and vapor f u g a c i t i e s are equal, the fugacity of the l i q u i d i s found.  Thus f o r a l i q u i d R> p a  0  .P  /n  T-  •Jo?  ~~ R T  f  ••• -Jp  V  L 1 Q  d P  Py/a p  (13)  ^P  0M  Pv/op  The fugacity of a component i n a mixture can be defined i n an ahalagous manner by the expression  o If P V T data f o r the mixture at the s p e c i f i e d composition at pressures from zero to that', of, the system are available, the i n t e g r a l i n equation ( 1 5 ) can be evaluated and the fugacity calculated. A c t i v i t y c o e f f i c i e n t s are calculated from f u g a c i t i e s according to the definition  where f£ i s the fugacity of the pure component at the same temperature, pressure and physical state as the component i n the mixture. Fugacities and a c t i v i t y c o e f f i c i e n t s used i n the t e s t i n g of vaporl i q u i d equilibrium data are normally calculated f o r the l i q u i d phase.  The  component fugacity f ^ i s therefore that of the component i n the l i q u i d .  Since,  8. however, the fugacity of a component i n the l i q u i d phase i s equal to that of the component i n the vapor phase under conditions of phase equilibrium, the fugacity i s evaluated from the vapor properties.  Calculation of Fugacities and A c t i v i t y C o e f f i c i e n t s from Experimental Data by Approximate Methods  Normally when vapor-liquid equilibrium data are measured, only the temperature, pressure, and composition of the co-existing phases are determined. Since the c a l c u l a t i o n of a c t i v i t y c o e f f i c i e n t s by exact methods requires a knowledge of p a r t i a l molal volume data, and since such data are almost never available, the c o e f f i c i e n t s are usually calculated by some approximate method based on the properties of the pure components.  Very often the problem i s further  complicated by,the fact that only a few of the properties of the pure components are known.  An excellent review of the methods of c a l c u l a t i o n to be used under  lU these circumstances i s given by Reid and Sherwood A c t i v i t y c o e f f i c i e n t s are calculated most simply i n terms of deviations from Raoult's law.  I f i t can be assumed that the fugacity of each  component i n the vapor phase i s equal to the p a r t i a l pressure of that component as given by Dalton's law, and i f i t can be assumed that the fugacity of the pure l i q u i d at the temperature and pressure of the mixture i s given by thei vapor pressure of that l i q u i d , then  YA  -M  (17)  This d e f i n i t i o n of a c t i v i t y c o e f f i c i e n t s i s generally only v a l i d under low pressures, and then only f o r solutions with r e l a t i v e l y i d e a l vapor behavior. The Lewis and Randall  4  rule gives a r e l a t i o n of more general v a l i d i t y .  If a mixture forms an i d e a l solution, i . e . no volume changes occur on mixing, then i t can be shown that the fugacity of a component i n a mixture i s equal  9to the product of the mole f r a c t i o n of that component and the fugacity of the pure material at the same temperature, pressure, and physical state.  f^-^ YA  (18)  =  (19)  In order to use t h i s rule to calculate a c t i v i t y c o e f f i c i e n t s , the fugacity of the pure vapor at the temperature and pressure of the mixture must he calculated f o r each component.  I f PVT data or equations of state are  available f o r the pure components, equation ( l l ) can be used to calculate these fugacities.  If such data i s not available,then  of thermodynamic properties can be used. proposed.  one of the generalized  Several such correlations have been  Charts based on reduced temperature  published by Newton  23 J  and Gamson and Watson  Oh  and reduced pressure have been .  More recently, correlations  based on an additional t h i r d parameter have been published. and Hougen ^  correlations  Lyderson, Greenkorr.  used the c r i t i c a l compressibility, P i t z e r et a l ^  used the 27  reduced saturation pressure at a reduced temperature of 0.7>  and Riedel  used  the slope of the vapor pressure curve at the c r i t i c a l temperature f o r t h i s additional parameter. The f u g a c i t i e s of the pure components can also be calculated from a  28 generalized equation of state.  Redlich and Kwong  have proposed such an  equation based on reduced temperature and reduced pressure}•Black ^, one based on reduced temperature and reduced pressure, and i n the case of polar substances 29 one s p e c i f i c constant; and Hirschfelder et a l  , one based on reduced  temperature, reduced pressure, c r i t i c a l compressibility and the slope of the vapor pressure curve at the c r i t i c a l point. The Lewis and Randall rule has been recommended f o r use at values of  10.  the reduced pressure of up to 0.6  At higher values of the reduced  pressure or for non-ideal solutions, a different method must be used to evaluate the fugacity of a component in a solution.  Most of the important  methods involve either the calculation of the constants for an equation ,of state for the mixture using the constants for the pure components, or the calculation of mixture parameters from the parameters of the pure components and the use of these mixture parameters and a generalized correlation to calculate the properties of the mixture. If the specific constants for an equation of state are available for each of the components present in a mixture, these constants can be combined to give an equation of state for the mixture.  A review  of the methods of  combining constants for the Van der Waals 3 ° , Keyes 3 , Beattie-Bridgeman 3 1  . Benedict-Webb-Ruben  2  ;  and v i r i a l - ^ equations of state, and of the accuracy  of the results,has been given by Beattie ^5,  j f the constants for a specific  equation of state are not known, one of the generalized.equations can be used. Both Redlich and Kwong  and Black  in their generalized equations.  give rules for combining the constants  From an equation of state for the mixture,  whether generalized or specific, the fugacity of each component can be calculated using standard thermodynamic relationships. If, instead of an equation of state, one of the generalized correlations is' used to evaluate the properties of a mixture, then the correlation patameters for the pure components must be combined to give those for the mixture.  Hougen, Watson, and Ragatz ^ and Lewis and Randall 37 have  discussed the combination of these parameters.  The fugacity of the components  of the mixture can then be calculated from the properties of the mixture using the relationship proposed by Joffe ^ .  11. Systems Studied and Type of Equipment Used A considerable amount of vapor-liquid equilibrium data i s available in the l i t e r a t u r e as exemplified by the compilations of vapor-liquid equilibriun data of Ju Chin C h u ^  and Hala et a l ^ ,  the compilation of physiochemical  constants by Timmermans^'"'", and the compilations of workers who have measured data at super atmospheric pressures by Comings^, Smith^,  Newitt^-  This  i s however a shortage of data f o r non-ideal systems at conditions of elevated temperatures  and pressures.  Since the testing of solution theories requires  experimental data f o r systems known to be non-ideal, and data f o r conditions i n which the deviations from i d e a l i t y are large, and d i f f i c u l t to treat a n a l y t i c a l l y , i t was decided that i t would be of interest to investigage such a system and to make vapor-liquid equilibrium measurements over most of the range of temperature  and superatmospheric  pressure i n which the vapor and  l i q u i d phases could co-exist. The non-ideal system chosen f o r study was the binary.  toluene-methanol  This p a r t i c u l a r system was chosen f o r three reasons.  Many measurements  had previously been made at t h i s u n i v e r s i t y on systems formed from the normal alcohols with benzene aid  toluene at atmospheric pressure ^5>^6,U7,48,U9,50^  i t seemed l o g i c a l to continue to work with a system i n t h i s group. l i q u i d equilibrium and enthalpy measurements 51>52,53  a+J  Both vapor-  elevated pressures  had been reported f o r the c l o s e l y related benzene-methanol binary system, and therefore measurements were available f o r comparison with those obtained i n t h i s project.  F i n a l l y , to the author's knowledge, the only published data on  the toluene-methanol  system i s the atmospheric pressure data of Benedict,  Johnson, Solomon, and Rubin  12. A l i m i t e d number of vapor-liquid equilibrium measurements were also made on the toluene-benzene system.  These measurements were made because i t  was planned to measure, at a l a t e r date, the benzene-toluene-methanol system, and therefore benzene-toluene binary data measured on the same equipment would be very valuable f o r checking ternary prediction methods.  Since the benzene-  23 toluene system had previously been investigated at elevated pressures  '  J  these measurements also served as a test of the experimental method and equipment. Several factors were considered when choosing the design of the equipment used i n t h i s project.  Since i t was planned to obtain equilibrium  values of t h e o r e t i c a l interest, i t was important that the apparatus give as accurate r e s u l t s as possible.  should  As well, however, i t was desirable  that the design be kept simple since the apparatus had to be b u i l t to withstand elevated temperatures  and pressures.  On the basis of these two  considerations, i t was decided that of the various types of equipment used to measure v a p o r - l i q u i d equilibrium data, one of the two s t a t i c methods, the dew-and-bubble-point method and the bomb method, would be most suitable. Since the dew-and-bubble-point method i s r e s t r i c t e d to the measurement of binary systems, and since i t was planned that eventually the apparatus would be used f o r the study of ternary systems, a bomb-type design was chosen.  APPARATUS AND PROCEDURE  13.  Apparatus  Introduction  In an e a r l i e r research project  13 55 ->>•'•' involving the author, a  s i m p l i f i e d version of an apparatus designed by Sage and Lacy"^" f o r phase equilibrium measurements was proposed and b u i l t .  When t h i s  simplified  apparatus was tested, i t was found to suffer from several major defects and therefore had to be r e b u i l t before i t could be used i n the present project. Since the rebuilding was done by correcting each defect separately rather than by discarding the equipmeht and returning to the o r i g i n a l design of Sage and Lacey  f  many changes from that design have occurred.  Most of the  features r e s u l t i n g from these changes are d i f f e r e n t to but not necessarily better than those described by Sage and Lacey"'". The f i n a l design provided an apparatus suitable f o r continuous use o at temperatures up to 200 250° C.  c. and f o r intermittant use at temperatures up to  Pressures as high as 1500 p . s . i . a . and, with one very small  modification, as high as 5000 p . s . i . a . could be used.  A detailed description  of the apparatus i s given i n Appendix I. General Arrangement  of Apparatus  The general arrangement of the apparatus i s shown i n Figure 1. The parts of the equipment designed to withstand elevated pressures are shown by heavy l i n e s and associated glassware by l i g h t l i n e s i n t h i s diagram. equilibrium c e l l A was immersed i n a constant temperature bath U.  The  This c e l l  contained a magnetically driven s t i r r e r (not shown) and, at the end of tube K, a detecting device which could be used to measure the l e v e l s of the vaporl i q u i d and organic-mercury interfaces.  Connected to the c e l l , and also  located i n the bath, was a sampling tube assembly D by means of which  samples  Figure 1  15of the vapor and l i q u i d phases could he taken.  The bath and thus the c e l l  temperature was measured with a platinum resistance thermometer and the c e l l pressure by means of two pressure gauges F and G. Bath Temperature Control and Measurement The o i l bath temperature was controlled with a c i r c u i t based on a Leeds and.Northrup platinum "thermohm" (resistance thermometer) and Mueller Bridge.  The thermohm was located i n the bath, and any change i n i t s  resistance from that corresponding, to the desired bath temperature resulted i n an out-of-balance signal from the Mueller Bridge.  This out-of-balance  signal was used, a f t e r amplification, as the input to an off-on c o n t r o l l e r . The temperature which was recorded i n t h i s work was that indicated by a platinum resistance thermometer suspended from the bath top so that the sensing element was located near the centre of the equilibrium c e l l .  The  thermometer was c a l i b r a t e d i n 1959 by the National Research Council of Canada. Since the temperature that was measured was that of the o i l surrounding the equilibrium c e l l and not that of the c e l l i t s e l f , an a u x i l l i a r y temperature survey was c a r r i e d out, using a sensitive thermocouple-bridge assembly i n which the temperature at seven points on the c e l l and at one point adjacent to the platinum thermometer were measured. temperature at the-thermometer  This survey showed that the  location and that of the c e l l opposite that  location were e s s e n t i a l l y i d e n t i c a l .  The r e s u l t s of the survey are given i n  Appendix I. The temperature of the bath was controlled to +0.05° C. and measured to +0.01° C  However, because of the p o s s i b i l i t y of small temperature  gradients i n the c e l l walls under some conditions, temperature values are ^ o reported to ,+0.1 C.  16. Pressure Measurement The pressure i n the equilibrium c e l l was measured with the aid of two Bourdon-tube type pressure gauges, F and G, connected to the through a mercury-filled l i n e and valves V 6, V 7> and V-8. c a l i b r a t e d f o r the-range 0 to 150 p.s.i.g. and 0 to 1500 and were accurate - from +8 to -l6 mm. for the second.  cell  The gauges were  p.s.i.g. respectively  of mercury for the f i r s t gauge and +80  mm.  Calibrations f o r both gauges are given,in Appendix I.  Equilibrium C e l l Volume and Location of  Interfaces  The volume of the equilibrium c e l l which could be e f f e c t i v e l y used was  that above the mercury surface i n the c e l l , and t h i s volume could be varied  by the addition or removal of mercury through valves V 8 and V 9* for t h i s use was  The mercury  stored i n mercury storage f l a s k J, connected to the equipment  through valve V 11,  and was  transferred between the f l a s k and c e l l using a  pressure generator I. The l e v e l of the mercury surface-in the c e l l was  determined by a  resistance bridge technique using a detecting or measuring head welded to the upper end of the stainless s t e e l tube K. -was h o r i z o n t a l l y suspended from the head.  A 0.005-in. diameter nichrome wire This wire was  connected to a  Wheatstone bridge, and the sudden change i n i t s resistance as i t was into the mercury phase was used to detect the l e v e l of the interface. resistance change was  lowered (This  caused by the difference i n e l e c t r i c a l conductivity of  the solvent and mercury phases.) The detecting head could also be used to determine the l o c a t i o n of the vapor-liquid interface.  Since the nichrome wire, when connected to the  Wheatstone bridge, c a r r i e d a small current, i t s temperature and thus i t s resistance was  dependent upon the thermal conductivity of the surrounding  17phase.  The thermal conductivity of the l i q u i d and vapor phases were normally  d i f f e r e n t , and therefore the wire resistance changed when the wire was lowered from the vapor into the l i q u i d phase. The measuring head could be raised or lowered inside the c e l l by means of a drive assembly.  This assembly contained an e l e c t r i c motor which  was used to rotate a lead screw connected to the measuring head tube K. the  As  lead screw rotated, i t also t r a v e l l e d v e r t i c a l l y , causing the head to move  v e r t i c a l l y as well.  The t r a v e l of the lead screw was limited, i n both  d i r e c t i o n s , by microswitches so that the head could not be accidentally damaged. The lower end of the lead screw was connected to a rod L which had the same outside diameter as the measuring head tube.  This rod passed through a t e f l o n  packed gland into a mercury-filled volume compensation c e l l E.  Since t h i s  cell,was connected, through valve V 5> "to the bottom of the equilibrium c e l l , no change occurred i n the equilibrium c e l l net volume as the measuring head was raised or lowered.  Samples of Co-existing Phases Samples of the vapor and of the liquid'phases could"be taken from the  equilibrium c e l l through valves V,1 and V 2 respectively and i s o l a t e d i n  the  sampling tube aseembly D.  Vapor samples were replaced, as they were  taken, with an equivalent volume of mercury and thus with no disturbance of the phase equilibrium i n the c e l l .  Liquid samples were taken by a rapid  removal of a small amount of the l i q u i d phase.  Experimental Procedure  Preliminary Steps Several preliminary steps were required before the assembled equipment was used.  It was f i r s t c a r e f u l l y pressure tested and cleaned and  18.  was then evacuated.  While s t i l l under vacuum, a l l of the pressure l i n e s and  f i t t i n g s , with the exception of the equilibrium c e l l , were completely f i l l e d with deaerated mercury from storage f l a s k J , and the equilibrium c e l l , i t s e l f was f i l l e d to a l e v e l 1 cm. above the lowest tubing connection.  With t h i s l e v e l as  datum and with the c e l l open to the atmosphere, the scales on the two gauges were set to•read zero pressure.  In use, the gauge readings had to be corrected  i n order to obtain the equilibrium c e l l absolute pressure.  A detailed  description of these preliminary steps, of the c a l c u l a t i o n of the gauge corrections, and of the use of the equipment i s given i n Appendix I I . Introduction of Material to C e l l • The system to be studied was introduced to the apparatus through a vacuum d i s t i l l a t i o n t r a n s f e r apparatus.  This apparatus consisted o f three  i d e n t i c a l sections, one of which i s shown i n Figure 1, (Flasks F 2, F 3, and F 10), and was provided with a single f l a s k F 1, common to a l l three sections. One component of the system which was to be studied was f i r s t poured into the o n e - l i t r e f l a s k F 10 along with a small quantity of drying agent, and the f l a s k was joined to the t r a n s f e r apparatus through a mercury-sealed glass j o i n t .  ground  After most of the a i r had been pumped out of the f l a s k with a  mercury d i f f u s i o n pump, the solvent was d i s t i l l e d from the f l a s k to the connected transfer vessel F 2 and frozen with l i q u i d nitrogen.  Any remaining a i r was  pumped o f f from above the frozen solvent, and the solvent was vacuum d i s t i l l e d to the adjacent transfer vessel F 3finally distilled  It was again frozen, evacuated, and  to vessel F 1.  The other component of the system to be studied was introduced i n a similar manner using a d i f f e r e n t section of the transfer apparatus. transferred to vessel F 1 i n the f i n a l d i s t i l l a t i o n .  I t also was  The mixture prepared i n F 1  in t h i s manner was f i n a l l y vacuum d i s t i l l e d to the intermediate storage f l a s k T.  19-  The solvent mixture was transferred from the storage f l a s k T to the  previously evacuated equilibrium c e l l i n the following manner.  Stopcock  S 13 was closed, valve V k and the mercury cut-off valve S 1 were opened, and hot  water was poured into the center of the f l a s k .  The solvent, which was j  warmed by the water, was forced, by means of i t s own vapor pressure, into the  equilibrium c e l l .  Preparation f o r Sampling  Once the solvent mixture had been introduced to the c e l l , valve V h was< closed and the i n i t i a l steps required before phase e q u i l i b r i m measurements could be made were c a r r i e d out.  The bath was heated to the desired temperature,  and the l i n e s connecting the sampling tube assembly D to the equilibrium c e l l were then purged with mercury." After t h i s purging the sampling tube assembly ?  was evacuated to remove any solvent that might have escaped from the c e l l a n d ?  the  assembly was r e f i l l e d with mercury.  A check was made to see that the  mercury l e v e l i n the c e l l lay between the center and lowest sampling ports and that the liquid-vapor interface lay between the l i q u i d and vapor sampling ports.  Valve V 3 a s then opened, connecting the mercury i n the sampling tube w  to that i n the equilibrium c e l l , and f i n a l l y  the magnetic s t i r r e r was turned on.  Measurements A period of one hour was allowed after the f i n a l adjustments were made to the c e l l before any measurements were taken. the  At the end of t h i s time,  c e l l temperature and pressure and room temperature and pressure were  determined and recorded. A sample of the vapor phase was next taken by the following method. Valve V 1 was opened, allowing vapor from the c e l l to flow into the assembly and to displace an equivalent volume of mercury from the assembly through V 3  20. into the c e l l .  Valves V 1 and V 3 were then closed.  A f t e r the sample had  "been i s o l a t e d i n t h i s manner, i t was transferred by vacuum d i s t i l l a t i o n through valve V 13 to sample c o l l e c t i o n f l a s k L.  The sample was c o l l e c t e d by  freezing i t i n the bottom of f l a s k L and sealing o f f the f l a s k above the frozen sample. When the vapor sample had been collected, the sampling tube assembly and sample c o l l e c t i o n f l a s k were re-evacuated i n preparation f o r taking a l i q u i d sample. the  Valve V 2 was then cracked, and a small amount of  l i q u i d phase was allowed to bleed out of the c e l l .  The sample was  c o l l e c t e d i n f l a s k M and removed by the method used f o r the vapor samples. Since the samples obtained were completely sealed, they could be stored i n d e f i n i t e l y before analysis.  Analysis Samples from the two binary systems studied i n t h i s work were analysed using either a gas chromatograph (benzene-toluene system) or an Abbe refractometer (toluene-methanol system). for both systems i s given i n Appendix IV.  Details of the method of analysis  21  MATERIALS Benzene  Eastman "spectro-grade for  S777" benzene was used, a f t e r p u r i f i c a t i o n ,  the vapor pressure and phase equilibrium measurements.  This material  was  stored f o r several days over calcium chips and then charged, along with carbon b o i l i n g chips and fresh calcium, to the s t i l l pot of a Todd "Precise Fractionation Assembly".  This s t i l l , using a 25-mm. diameter column packed f o r  90 cm. with U-mm.  diameter glass h e l i c e s , was  equivalent to 42 t h e o r e t i c a l  plates at t o t a l r e f l u x . The benzene was  d i s t i l l e d at t o t a l r e f l u x f o r several hours and  then removed at a r e f l u x r a t i o of 50 to !•  was  The f i r s t and f i n a l 20 percent  cuts  of the d i s t i l l e d solvent were rejected, and the center cut ( b o i l i n g point approximately  80.1  to  80.2°  C)  was  stored over sodium-lead a l l o y u n t i l used.  The p u r i t y of the center cut of the benzene was che.cked on a Beckman "GC2"  gas chromatograph, using a six-foot column of 8N8 F l e x o l  P l a s t i c i z e r on f i r e b r i c k .  No impurities were detected, with the chromato-  graph set f o r minimum attenuation, at e i t h e r 70°  or 100°  C.  Toluene Eastman  "X-325" toluene was dried with sodium-lead a l l o y and used,  without further p u r i f i c a t i o n , f o r vapor pressure and phase equilibrium measurements.  No treatment other than drying was  considered necessary, as  a check of the p u r i t y of the dried material using the gas chromatograph and column described above, with the chromatograph set f o r minimum attenuation, showed no impurities. urer, who  This r e s u l t agreed with that obtained by the manufact-  stated that the toluene had been tested by gas chromatography and  that no impurities had been found.  22.  Methanol  Eastman spectro-grade methanol was p u r i f i e d f o r the methanol vapor pressure and phase equilibrium measurements.  The solvent was f i r s t stored  for several days over, " D r i e r i t e " (anhydrous calcium sulphate) and then charged, along with fresh " D r i e r i t e " , to the s t i l l pot of the  distillation  column described e a r l i e r .  P u r i f i e d nitrogen, stated by the manufacturer  be 99'99 percent pure, was  introduced to the column just above the s t i l l pot  to prevent the formation of formaldehyde  .  to  The methanol was d i s t i l l e d at  t o t a l r e f l u x f o r several hours and was then removed at a r e f l u x r a t i o of 50 tol.  The i n i t i a l and f i n a l 20 percent cuts of the d i s t i l l a t e were rejected  and the center cut was  stored i n a nitrogen atmosphere u n t i l used.  A final  drying of the p u r i f i e d alcohol occurred when it,was poured into a o n e - l i t r e f l a s k and sealed to the transfer apparatus.  " D r i e r i t e " was added to the f l a s k  along with the methanol, and the alcohol and " D r i e r i t e " mixture was  allowed  to stand f o r at least one day before the methanol was d i s t i l l e d into the transfer vessels. The methanol p u r i t y was checked by gas chromatograph analysis according to the d e t a i l s given i n Appendix I I I .  The only impurity found  water, and the water content was found to be less than 0.1 mole percent.  was  VAPOR PRESSURE MEASUREMENTS  23-  Benzene Previous Work A considerable number of measurements have been made on the vapor pressure of benzene. Hyndman  57  Of these measurements, those of Bender, Furukawa, and  ; Gornowski, Anick, and Hixson  58  ? ; von Huhn ; and Griswold, Andres,  and K l e i n ^ are pertinent f o r comparison to the values reported i n t h i s project. Bender et al-^7 have measured vapor pressures at temperatures 100° C. to the c r i t i c a l point.  from  Reported values were calculated from an  equation given by the authors which they estimated to be accurate to about 0.1 percent.  59 Gornowski et a l reported c a r e f u l l y measured benzene vapor  pressure values f o r temperatures  from 130° C. to the c r i t i c a l point.  -No  59  estimate was given of the accuracy of the measurements. vapor pressure of benzene at temperatures  Young  measured the  from -10° C. to the c r i t i c a l point.  Reported values were calculated from an equation. No estimate was given of 2 the accuracy of 'the equation. Von Huhn has reported benzene vapor pressures at-temperatures from 100° to 300° C. The vapor pressures were measured to within kO mm.  of mercury (k mm.  at pressures up to 7500 mm.),and  temperatures  o to within about 0.1  C.  Reported values were obtained by that author from -3  smoothed curves.  Griswold et a l measured the vapor pressure of benzene at J  f i v e temperatures between 121° and 255° C. i n the course of t h e i r study of the benzene-toluene  binary system.  Pressures were determined to within 50 mm.  mercury and temperatures with an accuracy of approximately 0.5°'C  The  of  procedure  used by each of the above workers to p u r i f y benzene f o r the vapor pressure measurements i s described i n Appendix VII. The vapor pressure data of the above workers f o r the  temperature 57  range considered i n t h i s project i s given i n Table 1. Bender et a l  have  compared these r e s u l t s (with the exception of those of Griswold et a l ) with  2k.  t h e i r own and concluded that no one set could properly be c i t e d as unequivocal support f o r any other.  Results and Discussion  The vapor pressure of benzene was measured at s i x temperatures using one sample of the p u r i f i e d material.  The r e s u l t s of these measurements are  given i n Table 1 and shown plotted i n Figure 2 . been corrected  The reported pressures have  f o r the p a r t i a l pressure of mercury vapor i n the equilibrium  c e l l on the basis of Dalton's law.  Corrections were calculated f o r the  6o Poynting  e f f e c t , but were found to be n e g l i g i b l e , compared to the accuracy  of the pressure measurements, at a l l temperatures. The measured values agree, within the accuracy of the pressure measurements^with the c a r e f u l l y determined values of Bender et al^7 ^ every a  temperature  studied.  It i s of interest to note that the vapor pressure  measurements of Bender et al57 were also made over a mercury surface, and that the same corrections f o r the e f f e c t of mercury, i n the vapor phase applied;, as were used with the values reported here.  Rowlinson - has shown that the DJ  simple Dalton and Poynting corrections are not always adequate, p a r t i c u l a r l y at high pressures, to correct f o r the influence of mercury i n the vapor phase, but any error introduced i n t h i s way w i l l be the same f o r both sets of results. p  A comparison of the reported data with that of von Huhn Griswold, Andres, and Klein3 i  s  and of  of p a r t i c u l a r interest since these workers  have studied the phase e q u i l i b r i a of the benzene-toluene  system.  Since the  values measured i n t h i s project agree so well with those calculated from the equation of Bender et a l ^ ,  t h i s equation was used to calculate vapor pressure  values f o r comparison purposes at temperatures made.  at which measurements were not  TABLE 1  25-  VAPOR PRESSURE OF BENZENE Pressure - mm. of mercury Temperature  120.0 121.0 125.0 130.0 140.0 150.0 'i 116O.O 162.0 170.0 175-0 180.0 190.0 200.0 210.0 220.0 225.0 230.0 240.0 249.6 250.0 255-0 260.0 280.0  This Work  2540 4385  7065 10780 15860 22340  Bender et a l ' 5  2249 2303 2540 2841 35M+ 4371 5332 5541 6440 7056 7712 9159 10800 12640 14702 15820 17010 19570 22370 22420 23950 25570 32870  Gornowski et a l 58  Temperature - C. von Huhn  2265  p  Young59  Griswolc et a l 3  2230 2260  2825 3518 4331 '5277  2530 35^5 4372 5310  6368 7621 9050 IO67O  12500 14550 I685O  19425 22310 25520 32940  7050 7690 IO780  14700 15870 19580 22270 25560 32630  2821 3520 4335 5300 6386  5275  7617 9045 IO65O  10860  12453 14521 16825 19352 22182 25330 32780  19390 24310  26  273 The f i v e reported values of Griswold et a l d i f f e r from the measured (or calculated) values of, t h i s work hy from -4.8 percent at 162°  C.,  o to +1-5  percent at 255  C  Some of the disagreement can he explained i n  terms of the r e l a t i v e l y poor accuracy of the temperature measurements of 3 o Griswold et a l ; however, the disagreement f o r the values at l 6 2 C. and 255° C. i s about twice what could be explained i n t h i s  way.  3 The reported values of von Huhn values.  agree very w e l l with the present  At each temperature the d i f f e r e n c e • i n pressure i s less than the  uncertainty i n the pressure measurements. The excellent agreement of the benzene vapor pressures measured i n t h i s work with those reported by other workers, p a r t i c u l a r l y those of Bender 57 et a l , serves to v e r i f y both the accuracy of the method of measurements and the high degree of p u r i t y of the benzene used. On the other hand, the lack of agreement, at at least some temperatures,  of the values reported by  3 Griswold et a l  with those of any other workers, would indicate that t h e i r  values are i n error. Toluene  Previous Work Toluene vapor pressure measurements have been made at elevated 62 ? 63 pressures by Krase and Goodman ; von Huhn ; Zmaczynski ; and Griswold, 3  Andres, and K l e i n .  The American Petroleum Institute Research project 44  64  has reviewed e x i s t i n g vapor pressure measurements and calculated, from c r i t i c a l l y selected data, the constants f o r a vapor pressure equation v a l i d up to about 135°  C. 62  Krase and Goodman temperatures  from 129° C  have reported measured vapor pressures f o r  to the c r i t i c a l point.  These workers have given  28. 2 no estimate of the accuracy of t h e i r measurements. o o toluene vapor pressures from 120 to 300 within +k0 mm.  of mercury (h mm.  to within about 0.1° C.  has measured  Pressures were measured to  at pressures up to 7500 mm.)  and  temperatures  Reported values were taken from a smoothed curve of  the data by that author. toluene at temperatures  C.  Von Huhn  Zmaczynski  has reported the vapor pressure of  from 80° to 155° C  comparing the temperatures  The r e s u l t s were obtained by  at which water and toluene have the same vapor  pressure, and therefore pressures were not measured d i r e c t l y .  Vapor pressures  were reported i n the form of an equation r e l a t i n g the b o i l i n g temperature toluene and of water under the same pressure.  of  Temperatures calculated from  t h i s equation agreed with measured values to within 0 05° C. i n most cases. 3 Griswold et a l have measured the vapor pressure of toluene at three ^o o temperatures between 130 and 227 C. Pressures were determined to within _ o 50 mm.  of mercury and temperatures with an accuracy of approximately 0.5  Measured values were reported.  C.  The procedure used by each of these workers  to p u r i f y toluene f o r the vapor pressure measurements i s described i n Appendix VII The toluene vapor pressure data of the above workers that i s of interest i n t h i s project i s given i n Table 2. Results and Discussion The vapor pressure of toluene was measured at nine using f i v e samples.  temperatures  The r e s u l t s of these measurements are given i n Table 3  and shown plotted i n Figure 3-  T  n e  reported pressures have "been corrected f o r  the p a r t i a l pressures of mercury i n the equilibrium c e l l on the basis of 60 Dalton's law.  The value of Poynting  correction was calculated and found to  be n e g l i g i b l e compared to the accuracy with which pressure could be measured, f o r a l l points. The pressure measurements i n runs 2, 2A,  3> 3A, and h agree within  TABLE 2  29-  VAPOR PRESSURE OF TOLUENE Temperature  Temperature  c.  Calculated API " this project 6  II6.9  123-3 125.0 129-5 129-6 136.1 138.0 140.0 142.6 148.9  149.1  "  149-5 150.0 T55-7 160.0 161.0 175-0 175-5 176.7 180.0 186.5 189.O  194.O  200.0 203.5 204.4 214.4 220.0 225.0 226.0 227.0 234.5 240.0 246.0 250.0  Pressure-mm. o f mercury  1133 1270 1275 1495 1566 1643 1746 2021 2030 2050 2073 2350 2585 2641 3530 3565 3648 3897 4416 4629 5078 5659 6021 6120 7256 7959 8627 8766 8906 10010 10880 11890 12600  906 1074 1124 1262 1267 1488  Zmaczynski^  Krase ag^ Goodman  v. Huhn  2  Griswold et al3  906 1075 1268 1489  1277 1780 1660  1741 2026 2128 2347 2926  2595  3940 4650 5300 6280 7520  3900 4630 566O  7960  9030 10070 12160 12960  9050 10910  TABLE 3  MEASURED AND CALCULATED VAPOR PRESSURES OF TOLUENE Pressure - mm. of mercury Temp.  125-0 148.9 150.0 175-0 176.7 200.0 204.4 225-0 250.0  Temperature -  0  Run 2  Run 2A  Run 3  Run 3A  2033  2040  2022  2043  2037  3672  3661  6133  6125  6128  Run 4  6127  Run 30 1123 2008 2062 3519 3641 5646 6097 8613^ 12600  Run 33 1130 2018 2068 3523 3644 5649 6102 8577  Avg.  1130 2030 2065 3520 3655 5650 6120 8600 12600  C.  Avg. Deviation from Avg. 4 11 2 2 12 2 12 18  -  Calculated  1133 2021 2073  3530 3648 5659 6120 8627 12601  o  31 4.8r 4.7  T  T  VAPOR PRESSURE  r  OF TOLUENE  4.04.5k  'C.p. (64)  4AL 4.3r  5 4.2 w  o 0  E  •5 E E  Id CC  to CO  a.  a.  4.0k 3.9  r  3.8L 3.7  o o  3.6L  3.5L  3.4L_ 3.3L  3.2U 3.1 3.0L 1.6  1.7  1.8  L9  2.0  2.1  4 " X 10  3  Figure 3  2.2  2.3  2.4  Temperature = °K.  2.6  32:  the stated accuracy of the pressure gauges at each temperature measurements i n runs 3 0 and 3 3 -  as do the  However, the maximum v a r i a t i o n i n the  measured values when both groups of runs are considered^is greater than ;  that which would be expected from the uncertainty' i n the gauge readings alone.  The cause of the v a r i a t i o n i s not known, and because i t was  impossible  to decide i f one group of measurements was better than the other, a l l of the measurements were used f o r the determination of the averaged values. The constants f o r an Antoine equation have been determined  from  the experimental r e s u l t s and i t was found that the equation log P =  7 . 1 7 9 0 2  - I517.OO 242.76 + t  where P i s the pressure i n mm. t i s the temperature  in  of mercury o C.  allows the c a l c u l a t i o n of vapor pressures which agree with the average of the measured values to + 1 0 mm. to + 3 0 mm.  at pressures below 85OO mm.  at pressures above 85OO mm.  of mercury.  of mercury and  Values calculated from  t h i s equation are shown i n Table 2 f o r comparison with those of other workers. As shown i n Table 2 , excellent agreement i s found between the values of Zmaczynski^  3  and those calculated from the equation given above.  The fact  6^ that the values of Zmaczynski  2  also agree very well with the calculated API  values gives additional confirmation of the accuracy of the reported values. Very poor agreement i s found between the calculated values of t h i s 6 2  work and those of Krase and Goodman  .  At every, temperature  the value of  these two workers is>higher, and the difference varies from 0 . 6 to 1 1 . 2 percent (based on the calculated values). 2  The reported values of von Huhn  agree with those of t h i s work  within the accuracy of the pressure measurements at a l l temperatures  except  33> lkO° C; however, at t h i s temperature  the disagreement  i s less than that which  can he accounted f o r • hy the uncertainty i n both the pressure and  temperature  measurements. 3 The reported values of Griswold et a l t h i s work at only one temperature.  agree c l o s e l y with those of  At 189° C. the values are e s s e n t i a l l y  i d e n t i c a l ; at 227°c. they d i f f e r by 1.7 percent, and at I38 C. by 13.8 0  percent  The difference at 227° C. can be explained by the uncertainty i n the two values but the difference at 138°C. for t h i s temperature  cannot be explained i n t h i s way,  and the value  i s almost c e r t a i n l y i n v a l i d .  The excellent agreement of the toluene vapor pressures of t h i s work go  with those of Zmaczynski  , and the good agreement of these two sets of values  6h  with the API  c r i t i c a l l y selected values serves to v e r i f y the accuracy of the  vapor pressure values measured i n t h i s research.  Additional confirm-  ation of t h i s accuracy i s given by the good agreement between the present p  values and those reported by v. Huhn .  The lack of agreement of the values of  62 Krase and Goodman  with those of any other worker'would indicate that these  values are i n error. Methanol  Previous Work  Methanol vapor pressure measurements have been made over the same  65 temperature  range as studied i n t h i s project by Kay and Donham  Rao, Sarma, Swami, and Rao^. for temperatures  5Q  , Young^, and  Kay and Donham^ have measured vapor pressures  from 130° C. to the c r i t i c a l point and reported values taken  from a smoothed curve.  They estimated that t h e i r temperature measurements  were accurate to 0.05° C. and t h e i r pressure measurements to 25 mm. Young has measured the vapor pressure of methanol at temperatures  of mercury.  from -10° C.  34. the c r i t i c a l point.  The r e s u l t s of these measurements are reported i n the  52 form of an equation f o r which the accuracy i s not stated. reported measured vapor pressure values f o r temperatures The accuracy of t h e i r measurements was not stated. reported.  Rao et a l  have  from 90° to 196  0  C.  Measured values were  The procedure used by each of the above workers to p u r i f y methanol  for the vapor pressure measurements i s described i n Appendix VII. The vapor pressure measurements reported by each of the above groups of workers that are of interest f o r comparison to values determined i n t h i s work are given i n Table k. Results and Discussion The vapor pressure of methanol was measured at s i x temperatures using four samples.  The r e s u l t s of these measurements are given i n Table 5  and shown p l o t t e d i n Figure k.  The reported pressures have been corrected f o r  the p a r t i a l pressure of mercury i n the vapor phase on the basis of Dalton's law.  The value of the Poynting  correction was calculated and found to be  n e g l i g i b l e compared to the accuracy with which pressures were measured at a l l temperatures. The averaged values of the measured pressures have been included i n Table k f o r comparison with those of other workers.  These values agree within  the uncertainty of the pressure measurements with the values of Kay and Donham^ at 150° and 200° C. measurements, at 175  They also agree, within the accuracy of the pressure o  and 225  data, using temperatures  o  C. with values calculated from Kay and Donham's  5° C. above and below the desired values and an  equation of the form log P = A - B . T  65  TABLE 4  VAPOR PRESSURE OF METHANOL Pressure - mm. of mercury Temperature  99-0 100.0 105-3 123-6 125-0 127-0 149.1 150.0 151.3 170.0 173-7 175-0 175.2 180.0 200.0 220.0 225.0 230.0  Averaged value t h i s project  Temperature - C. Kay and Donnam^  Young59  2640  2621  5530  5454  10465  18315 30220 47540  10441  10336  16460  16292  18320  1803O  20330 30190 43480 47470* 51735  20089 29787 42573 46297 50414  Rao et a l 5  2  2590 2663* 3060 5172'" 5386* 5689 9825 10030* 13400 17070 17510* 17580  * Starred values calculated from two closest bracketting points using equation of the form log P = A - B . T  36. TABLE 5 MEASURED VAPOR PRESSURE OF METHANOL Pressure - nun, of Mercury Temperature Run 15 Run 19  100.0 125-0 150.0 175-0 200.0 225-0  10445 18330 30216 47522  26U5 5529 10446 18302 30221 47555  Run 20  Run 32  2635 5519 10494  2645 5528 10480  Temperature - C. Avg. Avg. Deviation from Avg.  2640 5530 10465 18315 30220 47540  5 5 21 14  3 16  37  38.  The vapor pressure values of Young59 lower than those measured i n t h i s research.  a  r  S  }  a  t every  temperature,  The difference i s about 0-7  percent (based on the averaged values) at 100° C. and increases to 2.6 percent at 225° C 52 The starred values of the vapor pressures reported f o r Rao et a l were calculated from the closest two points of these workers using an equation of the form log P = A - B . The calculated value i s higher at 100° C. than T the value measured i n t h i s project, and lower at every other  temperature.  While the values of these workers are on the whole closer to those of Young59 than to those of Kay and Donham^^^  o  to the present values, the agreement i s  r  so poor (varying by from 1-5 to 3-1 percent) as to be of doubtful value as 59 support f o r Young's measurements. The agreement of the methanol vapor pressure of Kay and Donham^ and those of t h i s work serves to v e r i f y the r e s u l t s obtained i n t h i s research. On 59 the basis of t h i s agreement i t would appear that the values of Young^ are 52 s l i g h t l y low and those o f Rao et a l are s i g n i f i c a n t l y i n error. x  (  39-  BENZENE-TOLUENE SYSTEM Previous Measurements  3 Griswold, Andres and K l e i n  have measured isothermal vapor-liquid  equilibrium values f o r the benzene-toluene  system at elevated pressures.  The  measurements were made with a d i s t i l l a t i o n type apparatus i n which the condensate was returned to the b o i l e r as a l i q u i d . nearest 1 p . s . i .  Pressures were measured to the  (50 mm. of mercury) using a gauge and temperature  accuracy of approximately 0.5° C  using  with an  thermocouples.  Thiophene-free benzene and nitration-grade toluene were p u r i f i e d f o r the measurements by f r a c t i o n a t i o n through a laboratory column packed with l 8 i n . of single-turn glass helices. were retained.  Heart cuts of 80 percent of the o r i g i n a l charge  The p u r i t y of each material was checked by vapor pressure  measurements, the r e s u l t s of which are given and discussed i n the section headed Vapor Pressure Measurements.  Mixtures of the p u r i f i e d benzene and  toluene were analysed by means of t h e i r b o i l i n g points. Temperature, pressure, and composition of the cb-existing phases were measured at temperatures  of 120°, l60°, l80°, 200°, 2h0°,  and 280° C.  The values reported f o r 200° e. are given i n Table 6. 2 Von Huhn  has also measured isothermal vapor-liquid equilibrium  values f o r the benzene-toluene  system at elevated pressures.  The equilibrium  measurements were made using a bomb type apparatus i n which both phases could be sampled.  Pressures were measured with two pressure gauges accurate i n the  range 0 to 7500 mm. of mercury to +h mm., mercury to +k0 mm.  and i n the range above 7500 mm. of  Temperatures were measured with the aid of thermocouples  to about 0.01° C Benzene and toluene of the highest p u r i t y commercially available at the time of the measurements were dried by d i s t i l l a t i o n and stored over sodium wire.  The p u r i t y of each material was checked by means of vapor pressure  TABLE 6  VAPOR-LIQUID EQUILIBRIA OF BENZENE-TOLUENE SYSTEM AT 200° (Griswold, Andres, and K l e i n ) 3  Pressure (mm. of mercury)  6770 7240 7910 8690 9720 10860  Mole Percent Benzene i n Liquid  15-4 27-0 38.5 56.6 77-7 100  Mole Percent Benzene i n Vapor  22.2 38.4 - 51.8 68.2 84.6  100  kl. measurements.  Smoothed values of the measured vapor pressures were reported,  and these values are given and discussed i n the section headed Vapor Pressure Measurements.  Mixtures of the p u r i f i e d materials were- analyzed with the a i d of  an interferometer. 2  Phase equilibrium values taken by v. Huhn  from smoothed curves of  from 120°to 300°.-C. at 2 0 ° i n t e r v a l s .  his data were reported f o r temperatures  The values reported f o r 200° C- are given i n Table 7Results  The vapor-liquid e q u i l i b r i a of the benzene-toluene system were measured at 200° C. The pressure and the composition of both the l i q u i d and at 20 points using s i x independent mixtures.  the vapor phases were determined  Measured pressures were corrected f o r the presence of mercury i n the vapor phase assuming Dalton's  law.  The r e s u l t s of the measurements are given i n Table 8. samples are represented by d i f f e r e n t run numbers i n t h i s table. equilibrium "x-y" p l o t of the data i s given i n Figure -5,  Independent A vapor-liquid  and a pressure-  composition p l o t i n Figure 6.  Calculation of A c t i v i t y C o e f f i c i e n t s  A c i t i v i t y c o e f f i c i e n t s were calculated f o r the measured points according to the d e f i n i t i o n  The fugacity of each component i n the vapor f^, was calculated using the )  equation proposed by J o f f e ^ .  |nA_ H f  =  Tcm,*-Tcl T  (HlH) I  RT  +  /  Pc-ux-fe* r5  (3.,) V  'rr\ix  ,  * {21)  TABLE 7 VAPOR-LIQUID EQUILIBRIA OF BENZENE-TOLUENE- SYSTEM AT 200' (von Huhn )  Pressure (mm. of mercury)  Mole Percent Benzene i n Liquid  10,780 10,220 9780 9270 8750 8310 78OO 7320 6800 6240 566O  100 91.4 82.5 73-4 63-9 54.1 44.0 33-6 22.8 11.6 0  -  Mole Percent Benzene i n Vapor 100 93-4 87.O 80.1 72.3 63.7 54.9 44.0 32.1 17.7 0  TABLE 8 VAPOR-LIQUID EQUILIBRIA OF THE BENZENE-TOLUENE SYSTEM AT 200° C. AS MEASURED IN THIS PROJECT  Run Number  8-200H G F E D C A •B 10-200E D C B A 14-200C B A I1-200F D C 9-200B A' 11-200B A 12-200D C B A  Pressure (mm. of mercury)  Mole Percent Benzene i n Liquid  Mole Percent Benzene i n Vapor  565O 6105 6105 6520 6520 '6725 6725 6825 6840  0 10.5 10.5 19.O 19.0 23.2 23.2 25.2 25-3  0 16.3 I6.5 28.2 28.4 33-8 33-8 36.3 ,36.4  7165 7445 7470 7840 7855 8025 8450 8460 8800 9050 9300 9350 9350 9450 9550 10500 10500 10600 10600 10780  32.4 38.0 38.7 45.4 45.8 48.7 56.1 56.4 62.6 69-3 72.8 73-6 73-5 76.4 77-8 95-4 95-4 96.8 97-0 100 '  44.3 50.3 50.8 57-4 58.2 60.7 68.2 68.1 74.1 .79-0 81.9 82.1 82.2 84.2 85.1 97-2 97-2 98.0 98.0 100  kh  0  10  20  30  40  50  60  70  80  MOLE PERCENT BENZENE IN LIQUID PHASE  Figure 5  90  100  12000  VAPOR-LIQUID PRESSURE FOR  EQUILIBRIUM  COMPOSITION  PLOT  BENZENE-TOLUENE  11000.  AT  200°  SYSTEM  C  I000C_  9000  800C_  700C_  600C_  MOLE 500OL  10  20  30  PERCENT  40  50  Figure 6  BENZENE  60  70  80  90"  100  he.  P s e u d o - c r i t i c a l temperatures and pressures were calculated f o r use i n equation ( 2 l ) assuming Kay's d e f i n i t i o n s  T m«= £ 3t TCU  (22)  C  PC(TM*~  ^uPcc  I  (23)  and the c r i t i c a l data quoted by the A.P.I. Project hh^  (Benzene-Tc=289-5°  C,  Pc=U8.6 atm., Zc=.27*+; Toluene-Tc=320.8° C*., Pc=U0.0 atm., Zc=.263). Mixture properties f o r use i n equation ( 2 l ) were calculated using the  25 generalized c o r r e l a t i o n of Lyderson et a l the  and reduced parameters based on  p s e u d o - c r i t i c a l temperature and pressures of equations (22) and (23)The fugacity of the pure l i q u i d at the temperature and pressure of O  .  X  the'mixture, f ^ , (a hypothetical standard state i n the case of benzeneJ was calculated from the equation 0  r  p  *  y i  \i Vt  -'q  J P  67 * In a recent paper, Ambrose and Grant of 318.6 + 0.02° C  f o r toluene.  have reported a c r i t i c a l temperature  While the value measured by these two  authors i s probably more accurate than that reported above, the error 6h introduced i n the a c t i v i t y c o e f f i c i e n t s by the use of the A.P.I. w i l l be very small.  value  hi. Saturated f u g a c i t i e s and l i q u i d volumes needed f o r the evaluation of equation (2h) were obtained from the following sources.  Saturated  f u g a c i t i e s f o r both benzene and toluene were calculated using the generalized 25 c o r r e l a t i o n of Lyderson et a l . The saturated l i q u i d volume  of benzene at 68  200° C. was obtained from the data reported by Organick and Studhalter  , and  the saturated l i q u i d volume of toluene at 200° C. from the data reported by Driesback f o r 20° C. and the method proposed f o r extrapolating l i q u i d ?  volume data by Lyderson et a l - \ 2  In the evaluation of equation (2h), i t was  assumed that the l i q u i d volume was independent saturated value.  of pressure and equal to the  ( i t i s of interest to note that a fugacity c o e f f i c i e n t of  0.8U6 was obtained f o r pure saturated benzene at 200° C. using the generalized c o r r e l a t i o n of lyderson et a l ^ while a value of O.815 was obtained from the 68 work of Organick and Studhalter which was based on experimental data. While 68 2  the value of Organick and Studhalter  i s almost c e r t a i n l y more accurate than  that calculated from the reduced c o r r e l a t i o n , the l a t t e r was used f o r the following reason.  The fugacity c o e f f i c i e n t s f o r the mixtures of benzene and  toluene had to be calculated using the reduced c o r r e l a t i o n .  Since these  mixture c o e f f i c i e n t s were calculated from the combined properties of benzene and toluene, and since these two substances are adjacent members o f a homologous series, i t seems l i k e l y that the same sort of error would appear i n the mixture c o e f f i c i e n t as appeared  i n the pure component c o e f f i c i e n t .  The  two fugacity c o e f f i c i e n t s appear as a r a t i o i n the c a l c u l a t i o n of a c t i v i t y c o e f f i c i e n t s , and therefore, when they both are calculated on the same basis, much of the error i n each should cancel. ) A c t i v i t y c o e f f i c i e n t s calculated as described above f o r the data i n Table 8 are given i n Table 9-  A c t i v i t y c o e f f i c i e n t s calculated i n terms of  deviations from Raoult's law (equation 17)  TABLE 9  48.  ACTIVITY COEFFICIENTS FOR"BENZENE-TOLUENE SYSTEM AT 200° C  Mole Percent Benzene i n Liquid  Benzene  Toluene  10.5 10.5 19.0 19.0 23-2 23.2 25-2 25.3 32.4 38.0 38.7 45-4 < 45.8 48.7 56.1 56. 4 62.a 69-3 72.8 73-6 73-5 76. 4 77-8 95-4 95-4 96.8 97-0  •993 1.005 1.001 1.008 1.007 1.008 1.007 1.010 •994 •992 .987 .988 .994 •991 - 1.007 1.005 1.011 •995 1.001 •999 1.001 •993 •994 •992 •993. • 991 •999  •996 •994 •995 •992 .991 •991 •991 •992 •995 •997 1.001 1.009 •'•999 1.007 •993  1.004 • 975 •983 •975 •998 .988 •993 1.003 .969 .969 1.007 1.072  Benzene Raoult' s law  .876 .886 .894 .901 .904 .905 .908 .909 .905 •917 .906 .916 .922 .924 .949 .944 .962 •953 .967 • 964 .966 .962 .965 .989 •989 •992 .989  Toluene Raoult's law  1.010 1.008 1.022 1.020 1.025 1.026 1.029 1.031  1.045  .I.O56  1.06l  I.O83 1.072 1.088 1.086 1.098 1.079 I.O96 1.094 1.122 1.112 1.120 1.135 1.131 1.131 1.172 1.119  h9.  t  -  *<•  Mx.  ( 1 7 )  P  have also been calculated and are included i n Table 9Discussion 2  The vapor-liquid equilibrium ."x-y" data of v. Huhn  and of Griswold  et a l f o r 200° C. and that obtained i n t h i s work are shown p l o t t e d i n Figure 7 -  Much b e t t e r agreement was found between the present vapor-liquid 3  equilibrium composition data and that of Griswold et a l than between the 2  present data and that of v. Huhn .  The maximum difference between the values  of the mole f r a c t i o n of benzene i n the vapor f o r a given mole f r a c t i o n 3  benzene i n the l i q u i d phase f o r t h i s work and that of Griswold et a l was about one mole percent, and most differences were less than t h i s value.  Differences  of up to about three mole percent i n the values of the mole f r a c t i o n benzene in the vapor f o r a given mole f r a c t i o n i n the l i q u i d were found between v. Huhn' 2  data and the values measured i n t h i s work, and a l l of v. Huhn's  values were  lower than the present ones. A pressure-composition diagram f o r the three sets of data i s given i n Figure 8.  In t h i s p l o t , much better agreement was obtained between the 2  data of v. Huhn  and the present data than between either of these sets and the 3  data of Griswold et a l .  At every pressure, however, the difference i n 2  composition between the l i q u i d and vapor phases i s less f o r v. Huhn's than f o r 2 the present work, and neither the l i q u i d nor the vapor compositions of v. Huhn agree, over the entire pressure range, with the values obtained i n t h i s work.  52The agreement between the pressure-composition values of Griswold et a l  and the present-values i s poor.  At every composition,the pressure  measured i n t h i s work i s the lower of the two.  The f a c t that better agreement  should be found between the two sets of data on a vapor-liquid equilibrium p l o t than on a pressure-composition plot i s not surprising, since the  temperature  •3  measurements of Griswold et a l were r e l a t i v e l y inaccurate, and since temperature J  has only a small e f f e c t on equilibrium composition and a large e f f e c t on pressure measurements.  The difference, however,,is greater than expected,  and  at one point i s about four times that which can be explained on the basis of a difference i n temperature  alone.  The greatest differences occur at the high  toluene concentration end of the curve, and i t was noted i n the section headed Vapor Pressure Measurements that one of the three reported vapor pressures of  3 Griswold et a l  was  s i g n i f i c a n t l y d i f f e r e n t than that of any other worker.  A l l but 3 of the 27 a c t i v i t y c o e f f i c i e n t s calculated f o r benzene using Joffe'sequation are within +1.0  percent of 1-0  and a l l c o e f f i c i e n t s are  A l l but 7 of the 27 c o e f f i c i e n t s f o r toluene are  within +1-5  percent of 1.0.  within +1.0  percent of l.O^and a l l but 1 are within +3-1  l a s t c o e f f i c i e n t , which varies from 1.0  by 7-0  percent of 1.0.  The  percent^is f o r a solution with  a very low toluene concentration, and i s thus subject to a very large experimental uncertainty.  The c o e f f i c i e n t s f o r both benzene and toluene show  no s i g n i f i c a n t systematic change i n value with concentration and are e f f e c t i v e l y equal to 1.0  f o r a l l concentrations.  e f f e c t i v e l y equal to 1.0, be equal to 1.0  Since the a c t i v i t y c o e f f i c i e n t s are  the r a t i o of the a c t i v i t y c o e f f i c i e n t s w i l l also  and the log of the r a t i o equal to zero and independent  mole f r a c t i o n of benzene.  The system benzene-toluene  at  200°  of the  C. forms,  h therefore, a perfect l i q u i d solution as defined by Lewis and Randall . C o e f f i c i e n t s calculated using the Raoult's law deviation expression d i f f e r substantially from 1.0;  the c o e f f i c i e n t s f o r benzene are a l l less than  531.0 and the c o e f f i c i e n t s f o r toluene are a l l greater than 1.0.  These  a c t i v i t y c o e f f i c i e n t s cannot, therefore, s a t i s f y a consistency test,and t h i s method of c a l c u l a t i n g a c t i v i t y c o e f f i c i e n t s f o r the benzene-toluene system o at 200  C  i s invalid.  METHANOL - TOLUENE SYSTEM  54.  Previous Measurements  54 Benedict, Johnson, Solomon and Rubin  have reported vapor-liquid  equilibrium measurements f o r the methanol-toluene mm.  of mercury.  system at a pressure of  76O  The measurements were made with an atmospheric-pressure,  constant-volume type apparatus. with a thermocouple  Temperatures  were measured, i n t h i s apparatus,  located i n a well i n the l i q u i d phase.  A barometer  reading was taken with each temperature reading and was used to correct the measured temperature to that corresponding to a pressure of "j60 mm.  of mercury.  Samples were taken of both the l i q u i d and vapor phases i n order to determine the composition of each. Methanol ation.  ( C P . grade) was p u r i f i e d f o r the measurements by f r a c t i o n -  The d i s t i l l a t e from t h i s f r a c t i o n a t i o n was dehydrated by refluxing i t  over magnesium methylate and was then r e d i s t i l l e d .  Special high-purity  toluene supplied by the Barrett Company was further p u r i f i e d by f r a c t i o n a t i o n before i t was used.  P u r i t i e s of both toluene and methanol were specified, and  the composition of mixtures of the two were measured by means of t h e i r r e f r a c t i v e index. The composition of both the l i q u i d and vapor phases was measured by  54 Benedict et a l 10 (page V I - l ) .  f o r 10 temperatures^and the values obtained are given i n Table An azeotrope b o i l i n g at 63.6° C. was found at a composition  of 88 mole percent methanol. The composition of the azeotrope b o i l i n g at 76O mm.  of mercury pressure  70 has also been measured by Berg and Harrison  .  These workers used Baker's  "Analyzed" toluene, and methanol p u r i f i e d by d i s t i l l a t i o n f o r the measurements. The type of equipment used f o r the azeotrope determination was not described e x p l i c i t l y but was probably a glass Othmer s t i l l .  An azeotrope containing  86 mole percent methanol and b o i l i n g at a temperature of 63.8  C. was found.  55Robinson, Wright, and Bennett compositions f o r the methanol-toluene  Tl  have also measured azeotropic  system at several temperatures.  "Eastman"-grade chemicals and laboratory-grade reagents were p u r i f i e d f o r the measurements.  The azeotropes were determined by measuring the composition of  '"constant-evaporation" mixtures.  Dried a i r was drawn through a prepared  mixture of toluene and methanol and a' sample of the l i q u i d removed p e r i o d i c a l l y f o r analysis. was not specified.  The pressure at which the measurements were made  Results of the measurements are given i n Table 17-  Results The vapor-liquid e q u i l i b r i a of the methanol-toluene measured at 125°, 150°, 175°. 200°, 225°, and 250° C  system have been  The pressure and the  composition of the vapor were measured over the entire l i q u i d composition range at each  temperature.  The results of the measurements are given i n Tables 11 to 16 VT-2 to VI-7)-  (pages  Reported pressures have'been corrected f o r the presence of  mercury i n the vapor phase assuming Dalton's law.  Independent samples are  represented i n these tables by d i f f e r e n t run numbers.  Isothermal vapor-liquid  equilibrium "x-y" composition diagrams and isothermal pressure-composition diagrams of the measured data are shown i n Figures 9 to 20. Equilibrium r a t i o s have been calculated f o r both methanol and toluene from the experimental data.  The calculated values are included i n Tables 11 to  16 and shown plotted as a function of the logarithm of the pressure'in Figures  21 and 22. An azeotrope was found f o r t h i s system at temperatures of 125°, and 175° C  The composition of the azeotrope at each temperature  150°,  was  determined from a large scale "x-y" composition diagram of the measured data and i s given as a function of temperature  and pressure i n Table 17-  The  56  0  10  20 MOLE  30  40  50  60  PERCENT METHANOL IN LIQUID  Figure 9  70 PHASE  80  • 90  100  7000 _  VAPOR-LIQUID PRESSURE FOR  EQUILIBRIUM  COMPOSITION DIAGRAM  METHANOL - TOLUENE AT  SYSTEM  1 2 5 ° C.  600C-  4500-  200C_  •  liquid phase  O vapor  10  20  30 MOLE  40  50  60  PERCENT Figure  10  70  METHANOL  phase  80"  I  90"  100  5  MOLE PERCENT  METHANOL IN LIQUID PHASE  Figure 11  8  VAPOR-LIQUID PRESSURE FOR  EQUILIBRIUM  COMPOSITION  DIAGRAM  METHANOL-TOLUENE AT  150°  SYSTEM  C.  10000 —  #  liquid phase  O  vapor phase  1000 —  10  20  30 MOLE  40  50  PERCENT  60  70  METHANOL  Figure 1 2  80  90  100  60  MOLE  PERCENT  METHANOL  IN  Figure 13  LIQUID  PHASE  VAPOR-LIQUID PRESSURE FOR  EQUILIBRIUM  COMPOSITION  DIAGRAM  M E T H A N O L - T O L U E N E SYSTEM AT  1 7 5 ° C.  13500-  12500 —  10500-  950C —  7500-  550C —  10  20  30 MOLE  40  50  PERCENT  F i g u r e ih  #  liquid phase  O  vapor phase  60  70  METHANOL  4  90  TOO  62  MOLE PERCENT METHANOL  Figure 15  IN LIQUID PHASE  3500C-  33000-  VAPOR-LIQUID PRESSURE FOR  31000.  EQUILIBRIUM  COMPOSITION  DIAGRAM  METHANOL- TOLUENE AT  200  6  SYSTEM  C.  29000_  2700C-  25000-  2300C-  21000-  19000  17000  15000  -  13000  11000  -  9000  •  liquid phase  O  vapor phase  7000  50001  10  20  30 MOLE  40  1  50 PERCENT  Figure l 6  1  60  70  METHANOL  80  90  100  6k  0  10  20 MOLE  30 PERCENT  40  50  60  70  METHANOL IN  LIQUID  Figure 17  80 PHASE  90  100  60000r 56000 52000-  VAPOR-LIQUID EQUILIBRIUM PRESSURE FOR  COMPOSITION  METHANOL- TOLUENE AT  DIAGRAM SYSTEM  2 2 5 ° C.  48000• 4400040000 36000 32000 28000 24000 20000 /6000 12000 •  8000  liquid phase  O vapor phase  4000  1 0 2 0  30 MOLE  40  50  PERCENT  Figure 18  60  70"  METHANOL  "90—roo  66  0  10  20 MOLE  30 PERCENT  40  50  METHANOL  Figure 19  60 IN  70 LIQUID  80 PHASE  90  100  67 60000  T VAPOR-LIQUID  56000  PRESSURE FOR  52000  T  EQUILIBRIUM  COMPOSITION  METHANOLAT  T  DIAGRAM  TOLUENE  250°  SYSTEM  C.  48000  4400C-  40000  £  36000  £ 32000 E E UJ 2 8 0 0 0  cr =>  CO CO  £  24000  20000  16000  12000 w  8000  #  liquid phase  O  vapor phase  4000-  10  20  30 MOLE  40  50  PERCENT  60 METHANOL  Figure 2 0  70  80  90  100  1000  2000  3000  4000  5000  6000  8000  10000  20000  30000  40000  50000  PRESSURE - mm. of mercury  Figure 21  OD  Figure 22  TABLE 17  70.  CALCULATED AND MEASURED VALUES FOR THE METHANOL-TOLUENE SYSTEM AZEOTROPE Pressure - mm. of mercury Worker  Temperature °C  This work  175-0 150.0 125.0  Composition  - mole percent methanol  Measured Values Composition Pressure  98-3 96.O  93-7  Calculated Value s Pressure Composition  18350 10530 5585  98-3 93-7  I856O IO58O 5520  96.O  63-6  88  760  88.0  770  Berg and ^ . 70 Harrison  63-8  86  760  88.0  769  Rohinson et al?  62.5 50.0 25-0 0.5  89.6  88.0 86.8 8U.5 82.2  --  Benedict et elf  1  1  89.I  88.6 87.8  —  71relationship between the temperature the nearest 0.1  and the composition can be expressed to  percent by the equation  x = 8 2 . 2 + .092t  (25)  where x = the mole percent methanol t = temperature i n °C.  The pressure of the azeotrope can be expressed as a function of  temperature  to within 1 - 5 percent by the relationship log P =  8 . 4 5 6 2  - I877.O T  ( 2 6 )  where P = pressure i n mm. of mercury T = temperature i n °K.  A comparison of the measured values with values calculated from equations (25)  and ( 2 6 )  i s given i n Table 1 7 -  A temperature-composition  diagram f o r  the azeotrope i s shown i n Figure 2 3 , and a pressure-composition diagram i n Figure 2k. Calculation of A c t i v i t y C o e f f i c i e n t s A c t i v i t y c o e f f i c i e n t s have been calculated f o r both components of the methanol-toluene  system according to the d e f i n i t i o n  a c t i v i t y c o e f f i c i e n t s from equation ( l 6 )  requires a knowledge of both the  fugacity of component k" i n the mixture, and fk°, the fugacity of pure rt  component " k " i n i t s standard state (defined as pure l i q u i d "k" at the temperature  and pressure of the mixture).  Since i n s u f f i c i e n t data are  72  200,  1  1  1  COMPOSITION  AZEOTROPE  1  1  1  150  o  /  /  o  I  /  *I00  +O i_  Q> CL  E  /  0)  ©  /  ^  /  /  /  /  /  O This work Benedict et al  3  50 -  3  ©  Berg and Harrison  3  Robinson et al  —  3  -  —  3  1  86  1  88  1  90 MOLE  1  92  1  94  1  96  PERCENT METHANOL Figure 23  1  98  100  200 175  150 125 100 Temperature = °C. Figure 2k  75  are  available f o r the methanol-toluene system to allow the c a l c u l a t i o n of  these f u g a c i t i e s by the exact relationships  In f \  S  J- ^ . ^ j j p  l«*A = ' " f ^ p + £ lo f ^ v o p - £  P  ^  4  |  M  t  P  ( ) 1 5  dP (V*-  (13) + In P^vop  (12),  f u g a c i t i e s of both components have been calculated with the a i d of several solution theories. are  Approximate methods based on these solution theories  i n common use by Chemical Engineers, and from them the fugacity of a  component i n a mixture can be calculated using the properties of the pure materials forming the mixture.  Fugacities determined i n t h i s way were used  with the f u g a c i t i e s of the pure components to calculate a c t i v i t y c o e f f i c i e n t s and the c o e f f i c i e n t s from each method have been compared and checked f o r thermodynamic consistency. The c r i t i c a l properties and the saturated l i q u i d volume at the temperature of the mixture were required f o r both methanol and toluene i n most of the c a l c u l a t i o n methods used.  The c r i t i c a l temperature and pressure of  methanol were obtained from the compilation of the properties of organic 56 solvents of Reddich and Toops  (Tc = 2^0.0° C ,  Pc = 78.6 atm.); the c r i t i c a l  volume from the tabulation of Reid and Sherwood ^ (Vc = 3-673 ml/gr); and the 1  saturated l i q u i d density from the compilation of the thermodynamic properties 72 of methanol of Smith  .  The c r i t i c a l temperature, pressure, and volume of  toluene were obtained from the A.P. I. Project kh^ atm., Vc = 3-12 ml/gr.).  (Tc = 320.8° C , Pc = hO.O  The saturated l i q u i d density of toluene was 73  calculated from the equation proposed by Guggenheim  f o r reduced saturated  l i q u i d densities  9r  --|+C(|-T0' ^d(l-Tr) /3  (27)  75-  The constants i n t h i s equation were evaluated using data quoted by 69 Driesbach  . A c t i v i t y c o e f f i c i e n t s have been c a l c u l a t e d from each of the  approximate methods described below using an Alwac I I I E d i g i t a l computer. Since the computer was used only as a t o o l f o r solving a n a l y t i c a l expressions, a description of the programs used has not been included. 1.  A c t i v i t y c o e f f i c i e n t s i n terms of deviations from Raoult's  law  If a vapor mixture behaves as a perfect gas, then the fugacity of a component i n that mixture  i s given by  fk=  (12)  and equation  reduces to  %? ^AVOP  (28)  =  il^op (29)  I f , i n addition, the e f f e c t of pressure on the fugacity of a l i q u i d can be neglected, then - f^vop  =  ^vap  (30)  and the a c t i v i t y c o e f f i c i e n t i s expressed i n terms of deviations from Raoult's law (equation 17)  A c t i v i t y c o e f f i c i e n t s have been c a l c u l a t e d f o r methanol and toluene from the measured data according to equation (17) and 175° C  f o r temperatures of 1 2 5 ° ,  The r e s u l t s of these c a l c u l a t i o n s are given i n Tables 18 to 23  (pages VI-8 to VI-13).  150°,  76. 2.  A c t i v i t y c o e f f i c i e n t s by the Lewis and Randall rule.  k According to the Lewis and Randall rule , the fugacity of a component i n a vapor mixture i s equal to the product of the mole f r a c t i o n ' o f that component i n the mixture and the fugacity of the pure component i n the vapor state at the temperature and pressure of the mixture.  The a c t i v i t y c o e f f i c i e n t  i s then defined, as given e a r l i e r , by V  %  =  ( 1 9 )  Fugacities of pure methanol and pure toluene vapors have been calculated f o r use i n equation ( 1 9 ) by two methods; a)  Generalized fugacity chart of Gamson and Watson 2k  Gamson and Watson  have presented a generalized chart of fugacity  c o e f f i c i e n t s ( r a t i o of fugacity to pressure) f o r gases as a function of the reduced pressure and temperature of the gas. From t h i s chart, f u g a c i t i e s have been calculated f o r pure methanol and f o r pure toluene at each of the measured pressures at temperatures  of 1 2 5 ° and 1 5 0 ° C.  The fugacity of each pure l i q u i d  i n i t s standard state was then calculated using the value of the saturated fugacity and the assumption that the l i q u i d volume was independent of pressure and equal to the saturated value.  The f u g a c i t i e s of the pure l i q u i d and of  the pure vapor calculated as described above were used with equation evaluate the a c t i v i t y c o e f f i c i e n t s f o r each material. calculations are given i n Tables l 8 to 2 1 .  (l9)to  The results of these  (More accurate values of the  f u g a c i t i e s of 'methanol - - and toluene would probably have been obtained i f 25 the improved generalized c o r r e l a t i o n of Lyderson et a l  could have been used;  however, 'this c o r r e l a t i o n , which i s presented i n terms of tables of values, contains too few values near the saturation conditions f o r accurate interpolation.)  77b)  Generalized equation of state of Black  Black^ has proposed a generalized equation of state of the form  V = & ? +fe-  where  |*r  (3D  b= § ^  (32)  a - 27 6RTc/8  = A +B/7r - C / V  !  (33)  f D/Tr 3 + m/l7T™  +!°  (34)  | V G R^T/ t H P r / V + KfP/ftop) + Wr/fr  (35)  3  and  The values of "A", B", n  "C , n  "D",  "F", "G , rt  "H",  and "K" are constants  independent  of the material f o r which the equation i s used, and the values of  "E  are functions of the material considered, E " being equal to zero  and "m"  n  n  for non-polar substances.  An expression f o r the fugacity c o e f f i c i e n t s of a  pure substance has been calculated from equation (3l) i n an exact manner by Black to give  (36) From equation (36), f u g a c i t i e s have been calculated f o r pure methanol and f o r pure toluene at each of the 'measured pressures at temperatures I5O , and 175° C. 0  (The value of P/Pvap was  set equal to 1.0  of 125°,  i n the case of  toluene to allow extrapolation of equation (36) to the a r t i f i c i a l state of a pure vapor at a pressure greater than i t s vapor pressure.)  The fugacity of  78.  each pure l i q u i d i n i t s standard state was the saturated fugacity and the assumption  then calculated using the value of that the l i q u i d volume was  of pressure and equal to the saturated value.  independent  The f u g a c i t i e s of the pure  l i q u i d and of the pure vapor calculated as described above were used with equation (19) to calculate a c t i v i t y c o e f f i c i e n t s f o r each material.  The  results of these c a l c u l a t i o n s are given i n Tables 18 to 23-  3-  Generalized equation of state of Hirschfelder et a l and fugacity equation of Joffe  29 Hirschfelder, Buehler, McGee and Sutton  have proposed a general-  ized equation of state f o r the gas region i n which the reduced pressure i s expressed as a function of the c r i t i c a l compressibility, the reduced temperature and volume, and the slope of the vapor pressure curve at the c r i t i c a l point. The equation can, with the a i d of experimental saturated l i q u i d density data f o r two temperatures, be extended to describe the l i q u i d region as well.  The  authors have derived from t h e i r equation of state, formulas f o r the thermodynamic excess functions and the fugacity c o e f f i c i e n t suitable f o r solution by a d i g i t a l computer. P s u e d o - c r i t i c a l properties f o r use i n t h i s equation of state were calculated from the c r i t i c a l properties of the pure components by a Mnear combination with mole f r a c t i o n .  The properties of the mixtures of methanol and 29  toluene were then calculated from Hirschfelder et a l ' s the measured pressures f o r temperatures  equations at each of  of 125°, 150°> and 175° C .  The mixture  properties calculated by t h i s method were used with the equation derived by Joffe-  3  f o r the fugacity of a component i n a mixture  T c 4 AH°-B\  em  ,to  evaluate the f u g a c i t i e s of both methanol and toluene.  (21)  79The f u g a c i t i e s of pure l i q u i d methanol and pure l i q u i d toluene were  29 also evaluated at each of the measured pressures using Hirschfelder et a l ' s equation and saturated l i q u i d density data.  Mixture and pure component  f u g a c i t i e s calculated i n t h i s manner were then used with equation'(l6) to calculate a c t i v i t y c o e f f i c i e n t s at temperatures  of 125°> 150°> and 175° C.  The r e s u l t s of these c a l c u l a t i o n s are given i n Tables 18 to 234.  Generalized equation of state of Redlich and Kwong 28 Redlich and Kwong  have proposed  an emperical equation of state  of the form  P = RT/(V-±0 <*  where  a/r' V(V+b)  O. 42 78 R Tc2 r / Pc l  b = 0 0867 RTc/Pc. For convenience  (37)  / L  (  3  8  )  (39)  i n the use of the equation, the terms  R-_ o / f ? T v  z r  B- b/RT  (ho)  (4i)  have been defined. The authors have also derived an expression f o r the fugacity c o e f f i c i e n t of a gas, from t h e i r equation of state, i n the form  /n4 = - l W 2 - B P ) - A* B l n ( l f BP/2)+2-1  (h2)  y  80.  Redlich and Kwong  28  have suggested that t h e i r equation can be  applied to a vapor mixture by combining  "A" and "B" f o r the components of the  mixture to give  Bm,* = I ^ B  (44)  t  In t h i s case, the expression f o r the fugacity of a component of the mixture becomes  /n4~-° 4 3 ^ 3 ( 2 - / ) ^ -gV flm\»  ft  - ln(2  + BP)nM,  mix  The f u g a c i t i e s of methanol and of toluene i n each of the mixtures studied at temperatures equation (45)-  of 125°, 150°, and 175° C. have been calculated from  Fugacities of pure saturated methanol and toluene were  calculated from equation (42) and used with the assumption l i q u i d volume i s independent  that the pure  of pressure to calculate the fugacity of the  pure materials i n t h e i r standard states.  A c t i v i t y c o e f f i c i e n t s were then  evaluated from equation ( l 6 ) f o r both toluene and methanol using the calculated fugacities.  The values of the c o e f f i c i e n t s determined  i n t h i s manner are  given i n Tables 18 to 23-  5-  Generalized equation of state of Black Black^- has proposed that h i s equation of state (equation 3l)  applied to vapor mixtures by combining  the values of "a", "b", and £  the pure components to give values f o r the mixture. the values of "b" to give  n  B  for  A l i n e a r combination of  81.  and a separate geometric combination of the polar and non-polar parts of the values of "a" to give  {Q-lf'L  and  =Z(*>\S*  ( U 8)  -4-  where § i s the non-polar part of g and was proposed.  ^  i s the polar part of  |  Using these combinations the equation of state f o r a mixture  becomes  v ^ + r M j -fcfa-lflifFrom t h i s equation Black fugacity of each component i n an n n  H  (U9)  \£( ^) '%f a  0  has derived an expression f o r the n  component mixture to give  T  RT  RT  (50)  (51)  where  (52)  (53)  •In  the derivation leading to the l a s t two terms of (50)>  that the terms " ^ i  Black  has assumed  " are independent of pressure and equal to the value of  He has estimated that the errors a r i s i n g from t h i s assumption are small and n e g l i g i b l e except i n the c r i t i c a l region.  82. The f u g a c i t i e s of methanol and toluene i n each of the mixtures studied at temperatures  of 125°, 150°, 175°,  calculated from equation (50). equal to 1.0  200°, and 225° C  have been  (The value of P/Pvap f o r toluene was set  i n the evaluation of the term y  k  P/P  k  v a p  -  n  Q  r  d  e  r  t Q  a  the use of the equation i n the region where the t o t a l pressure was greater than that of the vapor pressure of toluene.)  l  l  o  w  significantly  The fugacities of  saturated methanol and toluene were calculated from equation (36) and used with the assumption that the pure l i q u i d volume of each i s independent  of  pressure, to calculate the f u g a c i t i e s of the pure materials i n t h e i r standard state.  A c t i v i t y c o e f f i c i e n t s were then evaluated from equation (l6) for both  toluene and methanol.  The values of the c o e f f i c i e n t s determined  in this  manner are given i n Tables 18 to 23, and Tables 33 and- 34 (pages VI-21  and  VI-22). Thermodynamic Consistency Check of the Experimental Data Van Ness"^ has shown that isothermal a c t i v i t y c o e f f i c i e n t s f o r a binary mixture are thermodynamically  related by the expression  (54) The right hand side of equation (54) i s frequently very small, and the equation may be written, as noted e a r l i e r , as  In A Values of  =0  (10)  (n X^j^t. determined from the a c t i v i t y c o e f f i c i e n t s  calculated as described e a r l i e r are given i n Tables 2k to 27 (pages VI-lU to VI-17)-  The logarithms of the r a t i o of the a c t i v i t y c o e f f i c i e n t s obtained by  using Black's equation (50) ,are shown plotted as a function of the mole percent  83-  methanol i n the l i q u i d phase f o r temperatures of 225°  C  i n Figures  25  to  29-  125°,  150°,  175°>  200°,  and  Similar diagrams, showing only the "best f i t t i n g  l i n e (drawn by eye) f o r values from each of the calculationrmethods used at temperatures of 1 2 5 ° , 1 5 0 ° , and 1 7 5 ° C ,  are given i n Figures 3 0 to 3 2 .  Graphs s i m i l a r to those shown i n Figures 3 0 to 3 2 have been used to determine the value of the i n t e g r a l J I r\ c^/ ^ < J X | for activity coefficients 7  calculated from each of the approximate methods.  The value of the i n t e g r a l  was obtained i n each case by cutting the paper on which the graph had been plotted, along a l i n e drawn through the calculated points and also along the axis  In Y^X^-O  •  The two pieces of paper obtained i n t h i s manner and a  square of known area taken from the same sheet of graph paper were i n d i v i d u a l l y weighed, and the weights obtained were used to calculate the value of the integral.  The r e s u l t s of these calculations are given i n Table 2 8 .  Correlation of A c t i v i t y C o e f f i c i e n t s Obtained from the Equations of Black When one mole of a component "k" i s transferred to a solution at the same temperature and pressure, the change i n chemical p o t e n t i a l of the component i s given by  l > * - / 4 ) /H = R T In  and therefore  r  p =(K77n.£)  + /x£  (56)  The difference between the actual chemical p o t e n t i a l of the component i n the mixture and the chemical p o t e n t i a l i t would have i n an i d e a l solution i s given by  /4 =  R  T l " * A ^ + f l - R T U x - -  RTIAV*  (57)  0  10  20  30  40  MOLE  50  PERCENT  Figure 25  60  70  METHANOL  80  90  100  50  RATIO OF ACTIVITY IN THE SYSTEM  00  AT  COEFFICIENTS  METHANOL-TOLUENE 150° C.  50  50 O 00 1_—  Experimental data and Black's  Equation  Correlation  50 00.  10  20  30 MOLE  40  50  PERCENT Figure 26  60  70  METHANOL  80  90  100  0  10  20  30 MOLE  40  50  PERCENT Figure 2 7  60  70  METHANOL  80  90  100  1  1.50  RATIO IN T H E  1.00  OF  ACTIVITY  SYSTEM AT  COEFFICIENTS  METHANOL-TOLUENE 200°  C.  .50  -.50U  -1.00 — O —  Experimental  data and Black's  Equation  Correlation  -1.50  -2.0CL  10  20  1  30 MOLE  40  50  PERCENT Figure 28  60  70  METHANOL  80  90  100  1  1.50  1  1  1  1 RATIO  1  OF ACTIVITY  IN THE SYSTEM  1.00  1  AT  1  1  COEFFICIENTS  METHANOL-TOLUENE 225°  C.  .50  -.50  O Experimental data and Black's  -1.00- —  Equation  Correlation  •1.50 -2.oa  1  1 1  20  30 MOLE  i  40  i  50  PERCENT Figure 29  i  60  i  70  METHANOL  i  80  i  90  100 co co  MOLE PERCENT Figure 30  METHANOL  0  10  20  30  40  50  60  70  80  90  100  MOLE PERCENT METHANOL Figure 31  o  MOLE  PERCENT Figure 32  METHANOL H  TABLE 28  YALUES OF THE INTEGRAL  92.  | /n —  dz,  o  Calculation methods are numbered.to correspond with methods of c a l c u l a t i o n described i n text.  Method of Calculation of Activity, Coefficients  Positive Area  Negative Area  Difference i n • Area  Total Area  Difference i n Area Percent of Total  Temperature °C.  1 3 5 4 2A 2B  •345 •373 .405 • 403 .414 .440  •435 .405 •399 •376 • 346 •336  -. 090 .032 .006 .027 .068 , .104  .780 .778 .804 •779 .760 •776  -12 -4.1 0.8 3-5 8.9 14  125 125 125 125 125 125  1 3 5 4 2A 2B  •255 .296 •358 .361 •373 •390  •435 • 386 •345 .317 .265 .267  .180 .090 .013 .44 .108 .123  .690 .682 •703 .678 .638 .657  -26 -13 1.8 6.6 •17 19  150 150 .150 150 150 150  1 3 5 4 2B  •175 .231 • 304 • 322 .383 •  •439 .382 .281 • 243 .185  .264 .151 .023 .079 .198  .614 .613 .585 •565 .568  -43 -25 3-4 14 35  175 175 175 175 175  5  .282  •251  .031  •533  5-8  200  5  .280  • 223  .057  .503  11  . 225  . 93The term ^u.^ is. known as. the excess chemical .potential. The excess free energy of a one molar solution may be written^ from equation ('57)  ZzrfTUXi  ^FE-l*t/u*  (58)  Redlich and K i s t e r ^ have proposed r e l a t i n g .the - excess free energy of a binary solution.to experimental data by an equation of the form  (AF ^ RTx,x rB +C ( x ^ + D ( ^ r ^ t+ I:(^-^J E  r  t  Since  4 F - RK^.IAV, E  i t can e a s i l y be shown that  in  -  3 +  — J  (59)  IfJ  (58)  ^^  (60)  and therefore In  B(2 -x,) + Cf 6^,-1) v  The constants'"B , C , n  n  n  i 0 (^ ^)^Xa^V£(zr^(iox^ \) r  ( 6 l )  r  "D ."E , ... can.also be used to calculate the n  n  ;  individual a c t i v i t y c o e f f i c i e n t s  l« y, = * i [B + C f3*,-x J + D ( * i - ^ K s . V * 0 + £ ( * > - * ^ V 7 * r X t 2 (62)  A c t i v i t y c o e f f i c i e n t s f o r temperatures of 125°, 150°,.175°, 200°, and 225° C , calculated using the equation of Black^, have been correlated using a four-constant form of equation (59)- The equation was rearranged i n the form  * . , / n r -  S+C(*rV>  +  D ( x r i J  l  + B ( W  (59)  9h. for convenience  of c a l c u l a t i o n .  The c o e f f i c i e n t s "B",  "C", "D",  and "E"  were calculated to give a "least-square f i t " of the data assuming b *  X  1n  t  o  be the dependent variable.  The a c t i v i t y c o e f f i c i e n t s  for values of the mole f r a c t i o n of methanol less than 0.10 0.95  and greater than  were not.included i n the c a l c u l a t i o n of the constants since values of  the composition, and thus of the a c t i v i t y c o e f f i c i e n t s at the two extreme:, ends of the composition range, were subject to a high degree of experimental error. Values of the c o e f f i c i e n t s B", n  "C", "D",  c o r r e l a t i o n c a l c u l a t i o n s are given i n Table 29.  and "E" from the  The values of these  c o e f f i c i e n t s have been used with equations (62) and (63) to calculate a c t i v i t y c o e f f i c i e n t s f o r both methanol and toluene at temperatures 200°, and 225° C  of 125°, 150°,  175°,  The values calculated from these two equations are presented  in Tables 30 to 3^ f o r comparison with values calculated d i r e c t l y from Black's^ equation.  The percent differences given i n these tables are based on those  from Black's  equation.  The values of the c o e f f i c i e n t s "B", C", n  "B , n  and "E" have also been  used to evaluate equation (6l), the expression f o r the logarithm of r a t i o of the a c t i v i t y c o e f f i c i e n t s .  The r e s u l t i n g equations have been plotted i n  Figures 25 to 29 f o r comparison with the values calculated d i r e c t l y from  6 Black's  equation.  Discussion  Presentation of experimental data The vapor-liquid equilibrium "x-y  n  composition and pressure-  composition diagrams (Figures 9 to 20) and the equilibrium ratio-pressure diagrams (Figures 21 and 22) have been plotted using measured values of the pressure, temperature,  and composition; however, not a l l of the measured  TABLE 29  .95-  COEFFICIENTS OF REDLICH AND KISTER CORRELATION FOR METHANOL-TOIUENE SYSTEM  Temperature 125 150 175 200 225  C.  B  C  1.58^4 1-4273 1.2570 1.0985 .9875  •  .08944 .08107 .O765O .03718 .02484  D .1862 .1692 •1475 .2194 .1915  E -.0632 -.0082 +.0426 -.0035 -.0383  96. points have been included.  When more than one measurement was made f o r a  solution of a given composition, or when measurements were made f o r two or more solutions very close to one another i n composition, only one point i s shown.  Azeotrope The composition of the azeotrope was found to follow a l i n e a r relationship with temperature 175° C.  f o r the three temperatures  The fact that Rao et a l  125°, 150°, and  obtained a similar r e s u l t for, the  azeotrope i n the c l o s e l y related methanol-benzene system serves to confirm.the v a l i d i t y of a relationship of t h i s form. I f equation (25), the equation r e l a t i n g temperature  and azeotropic  composition, i s extrapolated to a composition of pure methanol, i t i s found that the azeotrope disappears at 193-4 C temperature  of 200° c.,  unreasonable.  No azeotrope was found at a  indicating that a value of about 193° C. i s not  I f equation (25) i s extrapolated.in the opposite•direction  to a temperature  of 63.6° c.,  methanol i s calculated.  an azeotropic composition of 88.0 mole percent  This value gives excellent agreement with the value  of 88 percent reported.by Benedict et a l . Much poorer agreement i s found between the calculated azeotropic compositions and the values reported Joy Berg and Harrison^ 62-5° C  and by Robinson et a l ^ f o r temperatures  respectively.  of 63.8° and  I t appears l i k e l y , therefore, that the-values of  these two workers are i n error.  The calculated azeotropic compositions and  71  those reported by Robinson et a l  o f o r temperatures, below 62.5 r  0 . show  very poor agreement;. however, extrapolation of equation(25) to the lower temperatures may not be v a l i d . The azeotropic pressures calculated from equation (26) agree reasonably well with both the values measured i n t h i s work-and.the value  97reported at 63-6  o  C. by Benedict et a l , p a r t i c u l a r l y when the very simple  nature of the equation and the r e l a t i v e l y large pressure range' over which i t i s applied are considered. A c t i v i t y c o e f f i c i e n t calculations A c t i v i t y c o e f f i c i e n t s calculated from the same experimental data hut using d i f f e r e n t approximation methods have quite d i f f e r e n t values.  The  a c t i v i t y c o e f f i c i e n t s , f o r example, of toluene f o r solutions containing 99-1 mole percent methanol are, when calculated i n terms of deviations from Raoult*s law, 6-55 at 125° C , 5-68 at 150° C , and 5.78 at 175° C. The  6 a c t i v i t y c o e f f i c i e n t s f o r the same solutions as calculated using Black's  k equation of state 'for pure toluene, and the Lewis and Randall  fugacity  rule, are 5-26 at 125° c., 3-95 at 150° C , a i d 3-23 at 175° c., or a difference of 20, 30, and hk percent respectively (percentages based on Raoult's law value).  Although these percentage differences are the  maximum that occur i n the a c t i v i t y c o e f f i c i e n t s f o r these solutions, each approximate method gives a s i g n i f i c a n t l y d i f f e r e n t value from the others. It i s obvious, "therefore, that at most, only one of the methods tested can give correct values. A c t i v i t y c o e f f i c i e n t s calculated from each of the approximate methods have been tested, as was described e a r l i e r , f o r thermodynamic 5 consistency using the Redlich and K i s t e r  test  (10) o At 125 C ., as shown i n Table 28, the value of the l e f t hand side of equation (10) f o r a c t i v i t y c o e f f i c i e n t s calculated from the experimental data using Black's^ equation i s only .006 units.  This value represents only  0.8 percent of the " t o t a l " value of the i n t e g r a l (the t o t a l value being  98.  defined as the sura of the p o s i t i v e area and the absolute value of the negative area under the curve of In ffi- versus x), and i s probably less TT than the uncertainty with which the i n t e g r a l was evaluated. temperature, from•Raoult s 1  At the same  the a c t i v i t y c o e f f i c i e n t s calculated i n terms of deviations law resulted i n a value f o r the i n t e g r a l of 0.09 units, or 12  percent of t h e - " t o t a l " value, and the c o e f f i c i e n t s calculated from Black's^ 4 equation f o r the pure components, and the Lewis and Randall  fugacity rule gave  a value of .104 units, or 14 percent of the " t o t a l " value of the i n t e g r a l . At 150° O., the value of the i n t e g r a l i n equation (10) f o r a c t i v i t y c o e f f i c ients calculated by Black's  method i s .013 units or 1.8 percent of the " t o t a l "  value, while at the same temperature  the other methods resulted i n values of  the • i n t e g r a l of up to 26 percent of the " t o t a l " .  At 175° C , the value of the  i n t e g r a l i n equation (10) f o r a c t i v i t y c o e f f i c i e n t s calculated by Black's^ equation was .023 or ^.h percent of the " t o t a l " value while the next best 28 method, that of Redlich and Kwong as large.  , gave a value of .079, almost four times  For the same temperature,  values of up to 4-3 percent of the " t o t a l "  were found f o r a c t i v i t y c o e f f i c i e n t s calculated by the other methods. From the r e s u l t s i n Table 28, i t i s obvious that each of the 6 methods of c a l c u l a t i o n used, except that of Black , results i n values of a c t i v i t y c o e f f i c i e n t s which are thermodynamically  inconsistent.  While the  cause of the f a i l u r e of each method i s not always d e f i n i t e l y known, i n many cases at least part of the reason i s f a i r l y obvious. 28 method proposed by Redlich and Kwong  The accuracy of the  depends i n part upon the  accuracy  with which t h e i r generalized equation of state, depending only on the c r i t i c a l temperature  and pressure, can be used to describe the properties  of the pure components used to form the mixture.  Since it"has been shown  that generalized equations based only on the c r i t i c a l temperature and  99pressure  are of r e l a t i v e l y poor accuracy, p a r t i c u l a r l y for polar substances,  28 the method of Redlich and Kwong  must be subject to the same l i m i t a t i o n .  A c t i v i t y c o e f f i c i e n t s calculated from the generalized equation of Rirschfelder et a l  on  oQ  and the fugacity equation of Joffe-  3  are i n error for 29  two reasons.  P s u e d o - c r i t i c a l properties f o r use with Hirschfelder et a l ' s  equation were calculated by a l i n e a r combination with composition of the properties of the pure components.  It i s u n l i k e l y that such a simple method  would be s a t i s f a c t o r y f o r a system containing a polar substance such as  was  •3D  considered  i n t h i s work.  Joffe's  fugacity equation i s also r e s t r i c t e d i n  accuracy by the assumption that the c r i t i c a l temperature and pressure  of the  mixture are given by K a y ' s ^ r u l e , and t h i s r e s t r i c t i o n would probably r e s u l t i n a d d i t i o n a l error i n the a c t i v i t y c o e f f i c i e n t s . It i s of i n t e r e s t to note here that Storvick and Smith attempted to calculate vapor phase enthalpies f o r several  have  polar-non-polar  systems, including the methanol-benzene system, using a generalized c o r r e l a t i o n . P s u e d o - c r i t i c a l constants were calculated using K a y ' s ^ method, and using these constants, mixture enthalpies were evaluated from the generalized  75 c o r r e l a t i o n of Hougen and Watson  .  When the calculated values f o r the  methanol-benzene system were compared with the experimental values of McCrackei and Smith'^, errors of up to 35 percent were found. for the other systems.  Similar errors were found  In an e f f o r t to improve the.accuracy of the c a l c u l a t i o n s ,  true c r i t i c a l mixture properties were used with the generalized correlations. Only a r e l a t i v e l y small improvement was  found.  It was  the conclusion of the  authors that generalized procedures give unreliable r e s u l t s f o r mixtures containing both a hydro-carbon and an associating substance. A c t i v i t y c o e f f i c i e n t s f o r a mixture, calculated from the properties k of the components used, and the Lewis and Randall fugacity  100.  rule, are incorrect because of the f a i l u r e of the fugacity rule. based on the assumption  This rule i s  of no volume change on mixing f o r the vapor phase, a  condition not met with non-ideal solutions, p a r t i c u l a r l y at elevated pressures. A s t r i k i n g demonstration of the f a i l u r e of the fugacity rule i s given by the  6 f a c t that Black's  equation of state f o r pure components can be generalized to  give a s a t i s f a c t o r y equation of state f o r mixtures using only.the properties of the pure components.  I f , however, the equation of state f o r the pure  components i s used d i r e c t l y with the fugacity rule to calculate mixture f u g a c i t i e s , large errors r e s u l t . A c t i v i t y c o e f f i c i e n t s calculated i n terms of deviations from Raoult's law are i n v a l i d because of the assumptions made i n the derivation of the Raoult's law expression.  The vapor phase of a non-ideal solution i s not a  perfect gas mixture, and the e f f e c t of pressure on the l i q u i d phase i s not negligible. Cause of apparent inconsistencies i n a c t i v i t y c o e f f i c i e n t s calculated by Black's method. i  While the value of the i n t e g r a l  J In Y,/X d^i u  was  small f o r the  6 a c t i v i t y c o e f f i c i e n t s calculated from the experimental data by Black's  method,  i t was not equal to zero as required by the Redlich and K i s t e r ^ test, nor even n e g l i g i b l y small at the higher temperatures.  Part of the inconsistency i s , of  course, due to errors i n the a c t i v i t y c o e f f i c i e n t s : errors caused by inaccuracies  6 in the experimental data and errors caused by the i n a b i l i t y of Black's of state to represent the system studied exactly.  equation  (Black^ has noted that f o r  some mixtures i n which special "chemical" e f f e c t s are present, e.g. strong interassociation or compound formation between unlike molecules, one or more of which i s nonassociated i n the pure vapor state, i n d i v i d u a l binary c o e f f i p ients may be required.  These binary c o e f f i c i e n t s are not r e a d i l y predicted from  the data f o r the pure components.)  Part of the inconsistency, however, i s  101. almost c e r t a i n l y caused by the use of a constant-pressure,  constant-temperature  form of the consistency test equation. The complete form of the equation used to check the thermodynamic consistency of isothermal data i s  f In A  d%, =  In order to estimate the importance the quantity  A  v  avg  w a  f  4£  (64)  (6k),  of the right hand side of equation  s defined where  RT The value of  dP  dp  (65)  £ i V avg required i n order to make equation (6k)  f i t the experimental  data exactly, was calculated, and i t was found that f o r each of the temperatures f o r which a c t i v i t y c o e f f i c i e n t s were determined  (125°,  150°, 175°, 200°,  and 225° C.) the value was a constant f r a c t i o n (constant within + k percent) of the average of the saturated volumes of methanol and toluene at the same temperature.  While the author makes no claim f o r the accuracy of the numerical  value obtained f o r  avg by t h i s method, the constancy.of the value ( i n  terms of the average volume of the pure components) does indicate that a change in volume .of mixing which r e s u l t s i n a n e g l i g i b l e value of the r i g h t hand side of equation (6k)  at 125° C  the same quantity at 225  o  (.006 , C. (-057  u n i t s ) can result i n a substantial value f o r . units).  A c t i v i t y C o e f f i c i e n t Correlation A c t i v i t y c o e f f i c i e n t s calculated from the four-constant Redlich and Kister'' c o r r e l a t i o n equation agree reasonably well with the experimental o values at temperatures  of 125  o and 150  C  At these two temperatures,  the  maximum difference between the experimental and the calculated values i s 7  102. percent, and most differences are considerably l e s s .  At 175°C the maximum  difference increases to 10 percent but most differences are less than 5 percent. At 200° and 2 2 5 ° C , the c o r r e l a t i o n r e s u l t s i n values considerably higher than those calculated from the experimental data.  The values agree i n the 10 to  90 percent composition range to within 10 percent but differences of hO percent occur f o r the d i l u t e solutions. The cause of the r e l a t i v e l y poor agreement f o r the values of the experimental a c t i v i t y c o e f f i c i e n t s and those calculated from the Redlich and K i s t e r ^ c o r r e l a t i o n at elevated temperatures  i s the fact that t h i s equation  applies exactly only under conditions of constant temperature; and pressure. Considering that the r e s t r i c t i o n of constant pressure i s not v a l i d f o r the a c t i v i t y c o e f f i c i e n t s reported i n t h i s work, the agreement between experimental and calculated a c t i v i t y c o e f f i c i e n t i s not unreasonable, except, perhaps, f o r d i l u t e solutions at the highest  temperatures.  Correlation of equilibrium r a t i o s with data reported by Rao et a l 80 An attempt has been made by Shemilt  to correlate the equilibrium  r a t i o s measured i n t h i s work f o r the methanol-toluene  system with those  52 obtained by Rao et a l  f o r the c l o s e l y related methanol benzene system.  To date a s a t i s f a c t o r y c o r r e l a t i o n has not been obtained.  IO3.  CONCLUSIONS AND RECOMMENDATIONS  Vapor Pressure Measurements Excellent agreement i s found between the vapor pressure of benzene measured i n t h i s work and the value calculated from the vapor pressure equation 57 given by Bender et a l at each temperature  f o r which a value was measured.  2 The present values also agree well with those reported by v. Huhn . The 58 59 values of Gornowski et a l and of Young , which agree well with one  57 another, are lower than those measured i n t h i s work; however,•Bender et a l  59 have noted that Young's  values may be shown to be consistently, low.  Vapor pressures calculated from the Antoine equation proposed i n  2 t h i s work f o r toluene agree well with values reported by v. Huhn  and by  63 Zmaczynski  .  Since vapor pressures calculated from t h i s equation d i f f e r  62 widely from values proposed by Krase and Goodman  f  and since the accuracy  2 of the equation i s supported by the values ,of v. Huhn  63 and Zmaczynski  , it  62 appears that Krase and Goodman's  values are' i n error.  At least one of the  3 values reported f o r the vapor pressure of toluene by Griswold et a l almost  i s also  certainly•invalid. Good agreement i s found between the vapor pressure of methanol  measured i n t h i s work and the vapor pressure interpolated from the data of  65 Kay and Donham f o r each temperature at which measurements were made, over the common temperature region. Since the accuracy of the values measured i n  65 t h i s work i s supported by the modern measurements of Kay and Donham  the  59 methanol vapor pressures reported by Young  appear to be s l i g h t l y low, and  52 those of Rao et a l Benzene-toluene  very low.  System  The vapor-liquid equilibrium values measured i n t h i s work f o r the o benzene-toluene  system at 200  C. show only f a i r agreement with those reported  for the same temperature by v. Huhn  2  3  and by Griswold et a l .  The equilibrium  104. 3 compositions of t h i s work agree reasonably well with those of Griswold et a l , but the agreement between the two sets of pressure measurements i s poor. was found, however, that at some temperatures of Griswold et a l  It  the vapor pressure measurements  f o r benzene and f o r toluene did not agree well with those  of other workers, and therefore t h e i r pressure measurements are probably i n 2 error.  The pressure measurements of v. Huhn  showed good agreement with those  obtained i n t h i s work, but the equilibrium composition measurements f o r the two sets of values were s i g n i f i c a n t l y d i f f e r e n t .  The cause of this difference  i s not known. Although the agreement between the values obtained i n t h i s work and 3 2 those obtained by Griswold et a l  and v. Huhn  i s only f a i r , the measurements  of these l a s t two sets of workers do not agree with one another as well as they agree with the values from t h i s work.  The fact that an excellent thermodynamic  consistency check was obtained f o r the present data gives further i n d i c a t i o n of accuracy of the measurements. Methanol-toluene  System  An azeotrope was found f o r the methanol-toluene  system at  temperatures  of 125°, 150°, and 175° 0. with i t s composition a l i n e a r function of temperature f o r these three temperatures. Extrapolation of t h i s l i n e a r relationship to calculate the azeotropic composition at 63.6° C. gives a 54 value of composition i d e n t i c a l to that measured by Benedict et a l . The 70 71 azeotropic composition reported by Berg and Harrison and by Robinson et a l would therefore appear to be i n error. A consistency check of a c t i v i t y c o e f f i c i e n t s calculated from the experimental data f o r t h i s system by s i x approximate methods shows that f i v e of the methods lead to incorrect values.  Of the methods of c a l c u l a t i o n used,  105-  6 only that proposed by Black  gives thermodynamically  c o e f f i c i e n t s , even at temperatures  as low as 125°C  consistent a c t i v i t y The method of t e s t i n g  5 consistency, that of Redlich and K i s t e r , indicated the most accurate a c t i v i t y o c o e f f i c i e n t s at 125 C , with the accuracy decreasing as the temperature increased.  The Redlich and K i s t e r ^ method i s s t r i c t l y v a l i d , however, only at  constant temperature and pressure, and much of apparent inconsistency at the higher temperatures  i s probably due to the fact that the r e s t r i c t i o n of  constant pressure does not apply. Since the experimental data were shown by Black^'s method to be thermodynomically  consistent, the thermodynamic consistency test has been used  to evaluate several approximate methods of c a l c u l a t i n g a c t i v i t y c o e f f i c i e n t s and thus of the solution theory on which the approximate methods are based. On the basis of t h i s t e s t , the Raoult's law expression, the Lewis and Randall fugacity rule, the fugacity equation of Joffe  , and the Redlich and Kurony  mixture equation are inadequate to describe the methanol-toluene  system at  elevated pressures. The four-constant Redlich and Kister-' equation used to correlate a c t i v i t y c o e f f i c i e n t s from Black's method allows, at the lower temperatures,  the  c a l c u l a t i o n of c o e f f i c i e n t s i n good agreement with those on which the equation i s based.  With increasing temperatures  for d i l u t e solutions.  the agreement becomes poorer, p a r t i c u l a r l y  This lack of agreement at the high temperatures  i s due  to the fact that the assumption of constant pressure, on which the equation i s based, becomes less and less v a l i d as the temperature increases. Recommendations f o r Future Work The approximate methods of c a l c u l a t i n g a c t i v i t y c o e f f i c i e n t s used in t h i s work were checked by an i n d i r e c t method, i . e . , by t e s t i n g the thermodynamic consistency of the calculated c o e f f i c i e n t s .  I f the a c t i v i t y c o e f f i c i e n t s  io6. had f i r s t been calculated by an exact method, a d i r e c t check would have been possible.  It i s therefore suggested that i n future work of the type presented  in t h i s project, the pressure-vblume-temperature  properties (the properties  necessary f o r the c a l c u l a t i o n of a c t i v i t y c o e f f i c i e n t s by exact methods) of the mixtures studied be measured as well as the phase equilibrium properties. The assumption  of constant pressure i n the thermodynamic consistency  check of a c t i v i t y c o e f f i c i e n t s introduces an error of unknown magnitude.  If  data on the isothermal volume change on mixing as a function, of composition were available f o r the l i q u i d phase, t h i s assumption  could be eliminated, and  a more accurate measure of the thermodynamic consistency of the experimental data could be obtained.  These data could be obtained from the volume  measurements suggested above, but i f i n future work complete temperature  pressure-volume-  data are not measured, i t i s suggested that at least the volume  change on mixing f o r the l i q u i d phase be  determined.  TABLE OF SYMBOLS A  constant i n Black's equation of state  A  terra i n Redlich and K i s t e r ' s fugacity equation  a  activity  a  a t t r a c t i o n constant i n Black's equation of state  a  constant i n Redlich and Kister's equation of state  B  constant i n Black's equation of state  B  c o e f f i c i e n t i n Redlich and Kister's correlations  B  term i n Redlich and K i s t e r ' s fugacity equation  .b  covolume constant i n Black's equation of state  b  constant i n Redlich and K i s t e r ' s equation of state  C  constant i n Black's equation of state  C  c o e f f i c i e n t i n Redlich and K i s t e r ' s correlations  c  number of components  c  constant i n reduced density equation  D  constant i n Black's equation of state  D  c o e f f i c i e n t i n Redlich and Kister's correlations  D  degrees of freedom  d  constant i n reduced density equation  E  constant i n Black's equation of state  E  c o e f f i c i e n t i n Redlich and Kister's correlations  F  free energy  F  constant i n Black's equation of, state  &F  excess free energy of mixing  f  fugac i t y  f°  standard state fugacity  107.  f f  fugacity of a component i n a mixture y a  p fugacity of saturated vapor  G  constant i n Black's equation of state  G°  non-polar term i n Black's fugacity equation  G°  polar term i n Black's fugacity equation  H  enthalpy  H°  enthalpy of i d e a l gas  £H  change of enthalpy on mixing  H  constant i n Black's equation of state  K  constant i n Black's equation of state  m  constant i n Black's equation of state  N  number of phases  P  pressure  Pc  c r i t i c a l pressure  Pr  reduced pressure  P p saturated vapor pressure y a  R  gas constant  S  entropy  T  temperature  Tc  critical  Tr  reduced  t  temperature  - °K.  temperature temperature - °C.  109V  ,volume  Vc  c r i t i c a l volume  V. . l i q u i d volume 'liq u  AV  volume change on mixing  V  p a r t i a l molal volume  •x  mole f r a c t i o n i n l i q u i d  y  mole f r a c t i o n i n vapor  Z  compressibility  Zc  critical  )g  activity coefficient  !•  a t t r a c t i o n c o e f f i c i e n t i n Black's equation of state  ^°  a t t r a c t i o n c o e f f i c i e n t at zero pressure  |"  non-polar part of a t t r a c t i o n  §  polar part of a t t r a c t i o n  coefficient  u  term i n Black's fugacity  equation  chemical /i°  compressibility  potential  chemical p o t e n t i a l i n standard  p.  excess chemical  J  reduced density  E  r  coefficient  Subscripts 1  state 1  1  component 1  2  state 2  potential  state  110. 2  component 2  i  component i  j  component j  k  component'k  P  constant pressure  T  constant temperature  avg  average  mix  mixture  LITERATURE CITED  111.  1.  Sage, B.H. and Lacey, W.N.  2.  von Huhn, W.  3.  Griswold, J . , Andres, D., and Klein,V.A.  4.  Lewis, G-N. and Randall, M.  174:102, 1948,  Trans. A.I.M.E.,  Forsctu Gebiete Ingenieurw., A2:129, 1931* Trans A.I.Ch.E.,  39:223, 1943.  Thermo dynamics and the Free Energy of  Chemical Substances , New York, McGraw-Hill Book Company Inc., 1923.  5.  Redlich,  0 and Kister,  6.  Black, C  7.  Robinson, C S . and G i l l i l a n d , E.R. Elements of F r a c t i o n a l D i s t i l l a t i o n .  A.T.  40:34l, 345, 19^8.  Ind. Eng. Chem.,  50:391, 1958.  Ind. Eng. Chem., (  4th Ed., New York', McGraw-Hill Book Co. Inc., 1950.  8.  Aroyan, H.J. and Katz, D.L. Ind. Eng. Chem.,  9.  Bahlke, W.H. and Kay, W.B.  Ind. Eng. Chem.,  10.  Kay, W.B.  28:1015, 1936.  11.  Kay, W.B. and Rambosek, G.M. Ind. Eng. Chem.,  12.  Sage, B.H. and Lacey, W.N.  13.  Whittle, D.J. M-A.Sc Thesis i n Chemical Engineering.  14.  Reid, R.C and Sherwood, T.K. The Properties of Gases and Liquids.  Ind. Eng. Chem.,  Trans A.I.M.E.,  43:185, 1951.  24:291, 19.38.  54:221, 1953-  136:136, 1940. U.B.C, 1958.  New York, McGraw-Hill Book Co. Inc., 1958. 15.  Guggenheim, E.A. Thermodynamics.  4th Ed., Amsterdam, North-Holland  Publishing Co., 1959-  16.  Van Ness, H.C  17-  Carlson, R.C, and Colburn, A.P. Ind. Eng. Chem.., 34:58l, 1942. E l l i s , S.R.M. and Bourne, J.R. Brighton International Symposium on Distillation, p-62, i960, preprint. Dodge,-B.F., Chemical Engineering Thermodynamics. New York, McGrawH i l l Book Co. Inc., 1944.  18. 19-  Chem. Eng. S c i . , 10:225,  1959-  20.  Herington, E.F.C Nature,  160:610, 1947.  21.  Coulson, E.A., Hales, J.F., and Herington, E.F.G.  Trans. Faraday Soc.,  44:629, 19^8. 22.  Tunell, G.  23.  Newton, R.H.  24.  Gamson, B.W. and Watson, K.M.  J . Phys. Chem.,  35:2885, 1931.  Ind. Eng. Chem.,  27:302, 1935. Natl. Pet. NPWS, Tech. S e c ,  36:R623, 1944-  112. 25-  Lyderson, A.L., Greenkorn, R.A., and Hougen, O.A. Generalized Thermodynamic Properties of Pure Fluids. Univ. Wisconsin Eng. Exp. Sta., Report 4, Oct., 1955-  26.  Pitzer, K.S., Lippman, D.Z., Curl, R.F., Higgins, CM., and Peterson, D.E. J. Am. Chem. S o c , 77:3433, 1955-  27-  . Biedel, L. Chem. Ing. Tech.,  26:83, 257, 679, 1954.  28.  Redlich, 0. and Kwong, J.N.S.  Chem. Revs., 39:333, 1946.  29.  Hirschfelder,.J.O., Buehler, R.J., McGee, H.A., and Sutton, J.R. Ind. Eng. Chem.,  50:375, 386, 1958.  30.  van der Waals, J.D. Kon. Ak. Amsterdam, 1880.  31.  Keyes, F.G. Proc. Nat. Acad. Sci., 3:323^1917 .  32.  Beattie, J.A. and Bridgeman, 0.C  33.  Benedict, M., Webb, G.W., and Rubin, L.C. J. Chem. Phys.., 8:334, 1940.  34.  Hirschfelder, J.O., Curtiss, CF., and Bird, R.B. Molecular Theory of Gases and Liquids.  35. 36. 3738. 39-  J. Am. Chem. S o c , 49:1665 1927".  New York, John Wiley and Sons Inc., 1954.  Beattie, J.A. Chem. Revs., 44:l4l, 1949Hougen, CA., Watson, K.M., and Ragatz, R.A. Chemical Process Principles- Part II, 2nd Ed., New York, John Wiley and Sons Inc., 1959Lewis, G.N., and Randall, M. Thermodynamics. 2nd Ed. New York, McGraw-Hill Book Co. Inc., 1961T Joffe, J. Ind. Eng. Chem., 40:1738, 1948. 7  Ju Chin Chu, Getty, R.J., Brennecke, L.F., and Paul, R. Distillation Equilibrium Data. New York. Reinhold Publishing Co., 19507  40.  Hala, E-, Pick, J., Fried, V., and Vilim, 0. Vapor Liquid Equilibrium. New York, Pergamon Press, 1958.  41.  Timmermans, J. The Physcio-Chemical Constants of Binary Systems i n Concentrated Solutions. I-IV, New York, Interscienic Publishers, Inc., 1959-  42.  Comings, E.W.  43.  Smith, J.M.  44.  Newitt, D.M. High Pressure Plants and Fluids at High Pressure. New York, Oxford University Press, 1940.  45-  Carol, M.M.  46.  Ind. Eng. Chem., Ind. Eng. Chem.,  39=948, 1947.  45:963, 1953.  B.A.Sc. Thesis in Chemical Engineering.  Drymose, L. B.A.Sc Thesis in Chemical Engineering.  U.B.C, 1952. U.B.C. 1957-  113hi.  Emerson, H-L. and C u n d i l l , T.G. B.A.Sc. T h e s i s i n C h e m i c a l E n g i n e e r i n g . U.B.C, 1951.  48.  Hamburg, A.  B.A.Sc. T h e s i s i n C h e m i c a l E n g i n e e r i n g .  U B . C , 1952.  49.  Howey, G.R.  M.A.Sc. T h e s i s i n C h e m i c a l E n g i n e e r i n g .  U.B.C, 1951.  50.  W a l d i c h u c k , M.  51.  McCracken,  52.  Rao, V.N.K., Sarma, K.J.R., Swami, D.R., and Rao, M.N.  M.A. T h e s i s i n A r t s and S c i e n c e .  U.B.C, 1950.  P.G., and Smith, J.M. A.I.Ch.E J o u r n a l ,  2:498, 1956J . S c i . Ind.  Res., l6B:4, 195753.  K r i c h e v s k i , I.R., Khazanova,  N.E., and L i n s h i t s , L.R. Z u r . F i z . Khim.,  31:2711, 195754.  B e n e d i c t , M., Johnson, C A . , Solomon, E., and R u b i n , L . C  Trans  A-I.Ch.E., 41:371, 1945. 55.  C r o i l , T.  56.  R i d d i c k , J.A., and Toops, E.E. Organic S o l v e n t s . 2nd Ed New York, I n t e r s c i e n c e P u b l i s h e r s , I n c . , 1955Bender, P., Furukawa, G.T., and Hyndman, J.R. Ind. Eng. Chem.,  57-  M.A.Sc. T h e s i s i n C h e m i c a l E n g i n e e r i n g .  U.B.C, 1959v  44:387, 1952. 58.  Gornowski, E . J . , Amick, E.H., and H i x s o n , A.N. Ind. Eng. Chem.,  59-  Young, S-  60.  P o y n t i n g , J.H. P h i l . Mag.,  61.  J e p s o n , W.B. and R o w l i n s o n , J.S. J . Chem. Phys., 23:1599, 1955-  62.  K r a s e , N.W. and Goodman, J.B. Ind. Eng. Chem., 22:13, 1930-  63.  Zmaczynski, M.A.  64.  American P e t r o l e u m I n s t i t u t e . S e l e c t e d V a l u e s o f P h y s i c a l and Thermodynamic P r o p e r t i e s o f Hydrocarbons and R e l a t e d Compounds. P r o j e c t 44, C a r n e g i e P r e s s , P i t t s b u r g , 1953-  65.  Kay, W.B. and Donham, W.E.  66.  Kay, W.B.  67.  Ambrose, D. and Grant, D.C  68.  O r g a n i c k , E . I . and S t u d h a l t e r , W.R.  69.  D r i e s b a c h , R.P. P h y s i c a l P r o p e r t i e s o f C h e m i c a l Compounds. i n C h e m i s t r y S e r i e s , 15, 1955-  39:1348, 1942.  P r o c . Roy. Soc. Dublin,.12:374, 1910. 12:32, 1881.  J . Chim. Phys., 27:503, 1930.  Chem. Eng. S c i . , 4:1, 1955-  Ind. Eng. Chem., 28:10l4, 1936. Trans. Faraday Soc. , 53:771, 1957Chem. Eng. P r o g . ,  44:847(1948). Advances  114. 70.  Berg, L. and Harrison, J.M.  Chem. Eng. Progr.,  71.  Robinson, E., Wright, W.A., and Bennett, G-W.  43:487, 1947-  J . Phys. Chem.,  36:658, 1932. 72.  Smith, J.M.  Chem. Eng. Progr.,  73.  Guggenheim, E.A.  74. 75-  Storvick, T.S., and Smith, J.M. J . Chem. Eng. Data., 6:28, 1961. Hougen, 0-A. and Watson, K.M. Chemical Process P r i n c i p l e s . Part 2., New York, McGraw-Hill Book Co. Inc., 1943.  76.  American Instrument Co. Inc. Superpressure Catalog 407Spring, Maryland, 1961.  77-  Perry, J.H. Chemical Engineers Handbook. McGraw-Hill Book Co. Inc., 1950.  78.  Sanderson, R.T. Vacuum Manipulation of V o l a t i l e Substances. York, John Wiley and Sons Inc., 1948.  79-  Hodgeman, C.D. Handbook of Chemistry and Physics. Cleveland, Chemical Rubber Publishing Co., 1949-  80.  Shemilt, L.W.  J . Chem. Phys.,  44:521, 1948. 13:253, 1945-  Silver  3 l Ed., New York, r(  New  31st Ed.,  Letter to the writer, February 6, 1962.  APPENDIX I - APPARATUS  I-l  Equilibrium C e l l The equilibrium c e l l (part number l ) * was machined from 304 stainless steel bar stock.  The c e l l chamber was 2 i n . i n diameter and  9 3/8-in. deep and therefore had a volume of about 480 c c The'top of the c e l l was sealed with a l i d (3), gasket (l4), and cap (2).  An assembly, drawing ©f t h i s seal i s shown i n Figure 1-8. The  gasket was a F l e x i t a l l i c  Gaske,t Company "Special Style R" stainless steel-and/  >  t e f l o n gasket, formed of alternate rings of V-shaped stainless steel and teflon. It was f i t t e d into a groove :ipi the top of the bomb and trapped there by a spiggot on the l i d . /  The lid'was forced against the gasket by s i x flat-bottom  set screws (32) which were held by the cap and acted through a 304 stainless i,  s t e e l protecting r i n g (4). • The cap i t s e l f was f i t t e d to the bomb by means of a thread which matched a similar one on the top outside surface of the bomb. When the set screws were tightened (torque-750 inch-pounds), s u f f i c i e n t pressure was exerted through the protecting ring on the l i d and gasket to seal the bomb against an i n t e r n a l pressure of 5000 p . s . i . a . Volume Compensating C e l l The volume compensating c e l l (43) was also machined from 304 stainless steel bar stock.  The c e l l c a v i t y was 7 3/^-in. high and-\ i n . i n diameter and  therefore had a volume of about 25 cc.  *The number which follows each part refers to the part number on the assembly and d e t a i l drawings shown i n Figures 1-8 to 1^27 included at the end of the text.  1-2 Relative Location of the C e l l s and Method of Clamping The two c e l l s were mounted so that the equilibrium c e l l was d i r e c t l y above the volume compensating one and were oriented so that the packing gland i n the end of the equilibrium c e l l and the one i n the end of the volume compensating c e l l were facing each other. The top bomb (or equilibrium c e l l ) was clamped on a cradle (53) located inside a constant temperature bath (104).  This cradle was formed from  two lengths of 2-in. channel i r o n held together with cross braces so as to l i e with the webs facing each other. to give a f l a t surface.  The top web of each channel was m i l l e d so as  The cradle was bolted at each end to the bath and was  positioned to l i e above the bath center.  A ^--in. thick mild s t e e l ground plate  (9) was bolted to the m i l l e d top of the cradle.  This plate had a hole machined  through i t s center, and the hole was of such a size that when the bottom two sections of the bomb were lowered through i t , the base of the top section was caught and rested on the plate. The bomb was clamped to the mild steel plate i n the manner shown i n Figure 1-8.  A 5-in. wide s p l i t r i n g clamp (lO) was f i t t e d into a -5-in. by £-in.  groove machined into the outer surface of the bomb.  Since the r i n g was wider  than the groove was deep, i t extended i^-in. beyond the outside surface of the bomb.  A r i n g cover was slipped over the ring, holding i t f i r m l y i n placejand  was bolted to the ground s t e e l plate.  When these b o l t s were tightened, the bomb  was held f i r m l y i n place and could not be moved either upwards or downwards. I t was held from rotating by two dog-point set screws (3*0The height of the channel-iron cradle above the bottom of the bath was  f i x e d so that the upper edge of the 2^-in. outside diameter section of the  bomb was l e v e l with the top of a packing gland (8) bolted to the bath bottom. This gland was sealed to the bath with a lead gasket.  Considerable  care was  1-3 t a k e n when l o c a t i n g t h e b a t h g l a n d t o ensure t h a t i t s c e n t e r l i n e and t h a t o f the bomb s u p p o r t p l a t e were t r u l y c o - i n c i d e n t a l and t h u s t h a t no s t r e s s was p l a c e d on t h e t h i n neck o f t h e bomb when i t was clamped i n p l a c e . The of 3 i -  n  constant  temperature b a t h was h e l d on a frame formed from l e n g t h s  a n g l e i r o n welded t o g e t h e r .  S i n c e t h e b a t h and frame were b o l t e d  t o g e t h e r , t h e upper bomb, b a t h , and frame formed a s i n g l e u n i t .  Also bolted  t o t h e frame, and t h u s f o r m i n g p a r t o f t h i s u n i t , was a s u p p o r t assembly f o r t h e bottom bomb.  (ho)  T h i s assembly was l o c a t e d so t h a t t h e bottom bomb was h e l d  v e r t i c a l w i t h i t s c e n t e r l i n e c o - i n c i d e n t w i t h t h a t o f t h e t o p bomb.  The b o t t o m  bomb was h e l d t o t h e s u p p o r t assembly w i t h a r i n g and c o v e r shown assembled i n Figure  I-ll.  M e a s u r i n g Head A d r a w i n g o f t h e assembled m e a s u r i n g head i s shown i n F i g u r e  1-10.  A 22-gauge copper w i r e , i n s u l a t e d w i t h a g l a s s wool s l e e v e , e n t e r e d a t t h e bottom o f t h e 3/8-in. b y l / 8 - i n . t u b i n g (l6) c a r r y i n g t h e m e a s u r i n g head and was pushed up t h e tube t o t h e base o f t h e head.  A t t h i s p o i n t , t h e w i r e was h a r d  t o t h e two i n t e r n a l w i r e s o f a Conax C o r p o r a t i o n  soldered  "Con-O-Clad" s t a i n l e s s s t e e l -  sheathed, m i n e r a l - i n s u l a t e d , chrome1-alumel thermocouple ( T l ) -  T h i s thermocouple,  w h i c h had a s h e a t h d i a m e t e r o f .062 i n . and c o n t a i n e d two 30-gSUge w i r e s , p a s s e d t h r o u g h a s e a l (92) i n t h e head and t h e n o u t o f t h e t o p o f t h e measuring head into the e q u i l i b r i u m c e l l .  The d e s i g n o f t h e s e a l was b a s e d on t h a t used b y  Conax C o r p o r a t i o n f o r t h e i r " T G - l U - A l  M  thermocouple g l a n d .  Leakage from around  the o u t s i d e o f t h e thermocouple was p r e v e n t e d b y c o m p r e s s i n g t h e s e a l a n t p l u g (92),  machined f r o m n a t u r a l magnesium s i l i c a t e , between a ceramic i n s u l a t o r (66)  s e t i n t o t h e head below t h e s e a l , and a g l a n d f o l l o w e r (67), c o n t a i n i n g a n o t h e r p o r c e l a i n i n s u l a t o r (68), s e t i n t o t h e head above t h e s e a l .  P r e s s u r e was a p p l i e d  t o t h e g l a n d f o l l o w e r b y t i g h t e n i n g a cap t h r e a d e d on t o t h e end o f t h e head.  i-h The follower was held from rotating, as the cap was turned, hy a small key ( 7 3 ) The insulators, sealant, and gland follower were standard units supplied 'by Conax Corporation f o r t h e i r T G - l 4 - A l " thermocouple gland.  With the use of  n  these standard pieces, a seal was made which was found to be s a t i s f a c t o r y f o r pressure varying from high vacuum to 5000 p . s . i . a . Since the head, when i n use, was often completely immersed i n mercury, the  p o s s i b i l i t y of a mercury short between the wire passing through the eenter  of the head and the enclosing walls had to be eliminated. sheathed conductor rather than a s o l i d one was used. -  For t h i s reason, a  A single sheathed wire  would have, of course, been quite as satisfactory,as the double one that was used, but sheathed wire p a i r s , designed f o r use as thermocouples, were more r e a d i l y available. The .005-in. diameter nichrome detecting wire was held below the measuring head by three pins ( 1 7 , 1 8 , 19) set into the cap.  The f i r s t p i n ( 1 7 )  was insulated from the cap by a t e f l o n sleeve ( 2 3 ) and was held i n place by a nut  ( 2 l ) screwed on to i t s upper end, and a small screw threaded into the side  of the cap so as to pinch the t e f l o n sleeve.  The two leads from the sheathed'  thermocouple were attached to the upper end of t h i s p i n and" h e l d there by a second nut ( 2 l ) , thus making t h i s p i n part of the c i r c u i t formed by the wire coming up the inside of the measuring head tube. to the p i n at a point . 05 i n . from i t s lower end.  The nichrome wire was connected The wire was slipped through  a small hole d r i l l e d through the p i n and the end t i e d around the p i n to give a strong connection.  The loose end was then passed through a small hook at the  bottom of a nichrome spring (70) held by the second p i n ( l 8 ) .  This p i n was also  insulated from the head with a t e f l o n sleeve and was held i n place i n the same manner as the f i r s t one. pin  The wire was then connected to the base of the t h i r d  ( 1 9 ) which was threaded into the measuring head cap.  The wire was connected  by passing i t through a hole i n the base of the p i n and tying the free end.  1-5 Since t h i s t h i r d p i n was not insulated from the head but i n good e l e c t r i c a l contact with i t , the measuring head tube could be used as a second lead from the detecting wire, and the problems associated with bringing two wires up the measuring head tube were eliminated. After the detecting wire was connected to the three pins,, the v e r t i c a l p o s i t i o n of each p i n was adjusted so that the nichrome wire was l e v e l . The p i n carrying the c o i l spring was then rotated u n t i l the wire was under a s l i g h t tension.  When the wire was heated,,either by the current being c a r r i e d  or by heating the c e l l as a whole, the wire expanded s l i g h t l y , but t h i s expansion was taken up by the spring, and the wire remained horizontal. ( O r i g i n a l l y a . 0 0 3 - i n . diameter platinum wire was used as the detecting element i n accordance with the recommendations of Sage and Lacy^.l However, t h i s wire had such a short operating l i f e that i t proved to be quite unsatisfactory.  Because of either solvent or mercury attack, the wire quickly  formed a spongy layer on i t s surface^and t h i s layer continued to grow u n t i l the wire-broke.  When the broken wire was removed and heated i n an open flame, the  spongy layer was very much reduced i n thickness.  Examination under a microscope  of a length of wire which had been previously heated, -showed the presence of wide " f i n s " l y i n g along what appeared to be die marks on the wire.)  Measuring Head Bridge  The l e v e l s of the interfaces i n the equilibrium c e l l were detected, as was described e a r l i e r , by noting a sudden change i n resistance of the detecting wire as i t was raised or lowered.  This change of resistance was  determined by making the nichrome wire and connecting leads one arm of a Wheatstone Bridge.  Since the absolute value of the resistance' change was not  important, the bridge was not c a l i b r a t e d . A diagram of the bridge i s given i n Figure I - l .  I t was designed so  Figure I - l  H  i  that each arm had approximately  the same resistance, and so that while two arms  were f i x e d a t h i r d would he varied i n order to achieve a balance.  Coarse  adjustment of the bridge was made with a 5-ohm variable r e s i s t o r and fine adjustment with the 50-ohm one connected i n p a r a l l e l with the smaller r e s i s t o r . When the instrument was resistor:].I was  i n use, i t was found that one setting of the coarse  satisfactory f o r a l l operating conditions.  A  50-0-50  micro-  ammeter was used as the sensing device for the bridge. The voltage source f o r the bridge was a 6-volt lead storage battery. This battery was connected through a variable r e s i s t o r by means of which the voltage supply to the bridge could be varied.  A second f i x e d r e s i s t o r i n the  connecting l i n e was normally l e f t i n the c i r c u i t when determining the mercury interface and was  shorted by means of a shorting switch, f o r a d d i t i o n a l  s e n s i t i v i t y , when determining the liquid-vapor interface.  Measuring Head Rod Assembly The measuring head rod assembly, carrying the l e v e l detector at i t s upper end, extended from one bomb into %he other. composed of s i x sections, the tubing (l6)  This assembly was  which supported the measuring head,  a universal j o i n t (shown assembled i n Figure I - l l ) j o i n i n g the f i r s t and t h i r d sections, a 5/8-i - diameter splined shaft, a l/Q-ln. n  diameter, 6-TPI, square-  threaded screw, and a length of 3/8-in. diameter stainless s t e e l rod. three sections are shown as a u n i t  The  last  (4l).  Measuring Head Rod Seal Both bombs were i s o l a t e d from the' atmosphere by glands which were tight to  5000  p.s.i.a.  given i n Figure 1-9  An assembly drawing of the seal on the top bomb i s  and. one showing the seal on the bottom bomb i n Figure I - l l .  The seal on the lower bomb was made using a linen-laminated b a k e l i t e p l a s t i c  1-8 packing stop (75) and several turns of •5--in. square-braided, t e f l o n - f i b r e packing. (hk).  Pressure was applied to the packing with a gland nut (I+5) and follower  This seal proved-satisfactory and o r i g i n a l l y the gland i n the top bomb  was designed f o r the same packing.  However, i t was l a t e r found that the long  length of packing required f o r a seal caused large f r i c t i o n loads inside the gland^and d i f f i c u l t y was experienced i n r a i s i n g and lowering the upper rod. (The corresponding d i f f i c u l t y was not experienced with the lower rod, perhaps because of the great r i g i d i t y of the lower bomb support.)  For t h i s reason, the  gland i n the upper bomb was shortened by i n s e r t i n g a monel-metal bushing (36) and was then packed with a tj--in. t h i c k , s o l i d t e f l o n ring.  The packing was  compressed, as i n the lower bomb, with a gland (6) and follower (5). ( \  Measuring Head Rod Drive An assembly drawing of the measuring head rod drive i s shown i n Figure 1-12 and i n d i v i d u a l assembly drawings of the two major components of the drive (reduction gear and universal j o i n t ) i n Figure 1-11. The squarethreaded lead screw, which formed part of the measuring head rod assembly, passed through a threaded bronze disk which was bolted to the frame (ho) carrying the lower bomb.  Thus,,if the lead screw-were rotated, i t also moved  v e r t i c a l l y , the d i r e c t i o n of movement depending upon the d i r e c t i o n of rotation of the screw. The lead screw could be rotated by means of a worm gear (93) and worm (92) combination having a 30 to 1 r a t i o .  The worm gear was f i t t e d over  the splined part of the measuring head rod and was held i n a gear case which i n turn was bolted to the lower bomb support assembly.  The gear was keyed to  the shaft with a r e l a t i v e l y l o o s e - f i t t i n g trapped key (9*0also f i t t e d into the gear case.  The worm was  This gear was held by two journal bearings  (90 and 87) and was keyed to a drive shaft (86).  The worm assembly (shaft,  1-9  worm, spacers, and bearings) was designed so that i t could be i n s t a l l e d or removed as a unit. The worm shaft was  driven by a l/6-horsepower A.C  reversing  induction motor through a 5 0 to 1 commercial reduction gear unit.  Since one  turn of the rod assembly raised the rod l / 6 i n . , and since the 1 7 2 5 r.p.m. motor was  connected to the rod through a 5 0 to 1 reduction gear and 3 0 to 1  worm and worm-gear set, the rate of v e r t i c a l movement of the rod was  . l 8 0 in.  per minute. As was  described e a r l i e r , the copper lead from the nichrome  detecting wire passed down the center of the measuring head tube and out from the tube to.a Wheatstone Bridge.  In order that the tube, and thus the copper  lead, would not rotate along with the lower part of the measuring head rod assembly, the two sections were joined by means of a u n i v e r s a l j o i n t (Figure I-ll).  An SKF  " 2 3 0 5 "  s e l f - a l i g n i n g b a l l bearing  ( 8 l )  wasl'held i n a mild  s t e e l case ( 5 1 ) which i n turn was  threaded on to the upper end of the  splined lead screw.  locked i n p o s i t i o n with a -j-in. flat-headed  screw ( 8 2 ) .  The case was  The bearing was  whose outside diameter was diameter of the case. diameter of 1 ^ i n .  trapped i n the case by a mild s t e e l l i d ( 5 3 )  such that i t extended \ i n . beyond the outside  The center of the l i d was  d r i l l e d out to an inside  Since the diameter of the center shaft ( 7 9 ) carrying the  bearing was only 1 . 2 6 i n . at the point where i t passed through the l i d , ample freedom of movement was  available to allow the s e l f - a l i g n i n g bearing to  help compensate f o r any s l i g h t misalignment of the two shafts. l/8-in.  The 3 / 8 - i n . by  diameter tubing which formed the upper end of the rod was  into the bearing center shaft ( 5 0 ) head p i n ( 7 9 ) .  a n  threaded  d was pinned i n place by a £-in.  The thread f o r the tubing was  socket-  at the base of a c a r e f u l l y  ground hole and was machined s l i g h t l y oversize so that the tubing center l i n e was  f i x e d by the ground sides of the hole,and not by the thread i t s e l f .  This  I-10  design was used to a l i g n the two shafts as i t was found to be impossible to make the tubing and shaft centerlines co-incident when the thread i t s e l f was used as the l o c a t i n g device.  Measuring Head Rod Drive C i r c u i t  A diagram of the measuring head rod drive c i r c u i t i s given i n Figure 1-2.  A four-pole, double-throw switch was used to c o n t r o l the d i r e c t i o n  of rotation o f the motor.  When t h i s switch was reversed, the p o l a r i t y of the  s t a r t i n g c o i l with that of the f i e l d c o i l was reversed, and therefore the d i r e c t i o n i n which the motor would start was also reversed. Four microBwitches, which were actuated by the l i p on the u n i v e r s a l j o i n t assembly, were used to -limit the t r a v e l of the measuring head. The four switches acted i n two p a i r s and, since the p a i r s were symmetrical, the operation of the upper l i m i t i n g switches w i l l be described.  only  A Minneapolis  Honeywell Regulator Company'"ISLI" two-circuit microswitch was wired i n combination  with a double-pole, double-throw relay i n such a manner that the  two were equivalent to one double-pole, double-throw switch.  ^  When the rod  assembly was raised t o such a p o s i t i o n that t h i s switch was opened, the l i n e s to both the f i e l d and s t a r t i n g c o i l s of the motor were broken, and a p i l o t l i g h t was turned on.  The rod could then be raised no further, but reversing  the p o s i t i o n of the four-pole switch took the actuated microswitch out of the c i r c u i t , and the rod could be lowered.  A second microswitch, a "BZ-2RW82"  single-pole, double-throw switch, was mounted a few hundredths of an inch above the f i r s t to guard against the p o s s i b i l i t y of f a i l u r e of the f i r s t This second switch, when actuated, opened the voltage supply l i n e .  switch.  When  t h i s switch was opened, no power could be supplied to the motor regardless of the p o s i t i o n of the four-pole motor switch, and the motor had to be turned by hand u n t i l the switch was closed again.  MEASURING HEAD  F i g u r e 1-2  1-12 Bomb Tubing Connection The d e t a i l s of the ^--in. diameter tubing connections on the upper and lower bombs i s given i n Figure 1-10.  These connections were based on  the standard design used by the American Instrument Company^  and were made  so as to meet-Perry's^ recommendation of having at least four f u l l threads engage on the gland nut (60) when sealing against pressure of up to 2000 atmospheres. A l l other tubing connections shown i n Figure I ( i . e .  connections on  valves, , tees, cmsses, couplings, etc.) were made according to the s p e c i f i c a t i o n of the manufacturer  of each item.  In every case the unit and connections were  s p e c i f i e d as being suitable f o r pressures of 10,000 p . s . i . a . or greater.  Equilibrium C e l l S t i r r e r A magnetically driven s t i r r e r was used to agitate the contents of the equilibrium c e l l .  An assembly drawing of the s t i r r e r i s given i n Figure  I-10.  A small well was machined i n the underside of the l i d used to seal the  cell.  A General E l e c t r i c "22U18B" A l n i c o II magnet (28) was placed i n t h i s  well and supported there on the end of a shaft passing through two s t e e l b a l l journals (48).  stainless  The journals were f i t t e d into a stainless steel bar  (26) held on the underside of the l i d by two screws (30 and 38)-  When the  supporting bar and magnet were i n s t a l l e d , the magnet's p o s i t i o n was adjusted by s l i d i n g the magnet shaft through the two bearings, u n t i l i t was as high i n the bomb as was possible without touching the under-surface of the l i d . stirrer (25),  A  consisting of a l / 8 - i n . thick bar carrying two long l4-gauge  nichrome wire vanes, was held on the magnet shaft below the support bar by two nuts (29 and 3 l ) -  The length of the nichrome vanes was  such that under operating  conditions they extended into the l i q u i d solvent but not the mercury phase. r i n g formed from 20-gauge nichrome wire was welded to the vanes near the bottom to act as a s t i f f e n e r .  A  1-13 When the s t i r r e r was allowed to rotate f r e e l y , i t would follow the driving magnet up to a l i m i t i n g speed and would then drop out. No external indication was available to show whether or not the s t i r r e r was operating. The c e l l s t i r r e r was therefore designed so that one of the screws ( 3 0 ) holding the support bar ( 4 4 ) extended down below the l i d and prevented the s t i r r e r from making a complete revolution.  With t h i s design, a d i s t i n c t  "ping" could be heard through a rod placed against any part of the equilibrium c e l l every time the s t i r r e r h i t the screw.  The o s c i l l a t i n g motion of the  s t i r r e r , r e s u l t i n g from the s t i r r e r h i t t i n g the screw and bouncing back, seemed, i n a test made outside of the bomb, to s t i r very e f f e c t i v e l y . The s t i r r e r was driven with an externally mounted " U 5 3 0 4 " horseshoe type Alnico V General E l e c t r i c magnet ( 1 5 ) f i t t e d into the inside of the protecting ring ( 4 ) on the upper bomb.  A small brass nut ( 1 2 ) threaded into  the bomb cap ( 2 ) acted as a bearing f o r the shaft used to rotate the magnet. This nut also acted as a stop f o r a c o l l a r ( 1 3 ) which was f i t t e d over the magnet shaft and which was used to adjust the v e r t i c a l p o s i t i o n of the magnet. The d r i v i n g magnet was rotated by a variable-speed s t i r r e r motor.  This gear-  driven u n i t , i n which the speed could be varied by changing the supply voltage, was coupled to the magnet shaft through a very loose f i t t i n g two-pin coupling and was mounted on one of the plates forming the l i d of the bath. The upper bomb, i t s l i d ,  and i t s protecting r i n g were a l l made of  3 0 4 s t a i n l e s s s t e e l i n order to keep f l u x losses between the two magnets to a minimum.  I t was found that when the thickness of the l i d at the bottom of  the well ( i . e . the minimum distance by which the two magnets were separated) was 0 . 5 in., as required f o r a safe design f o r 5 0 0 0 p . s . i . a . i n t e r n a l pressure, the maximum v e l o c i t y at which the s t i r r e r would respond to the d r i v i n g magnet was very low.  Since the maximum pressure at which i t was planned to use the  equipment i n i t i a l l y was not 5 0 0 0 p . s - i . a . , but 1 5 0 0 p . s . i . a . , the thickness of the material at the bottom of the l i d was reduced to 0 . 2 5  i n  -  With t h i s  I -Ik  thickness separating the 'two magnets, the highest v e l o c i t y at which the s t i r r e r would follow the d r i v i n g magnet was raised to approximately with the range 100 to 150 r.p.m. being the most satisfactory.  200 r.p.m.  ?  This change i n  thickness of the l i d meant that the equipment as discussed above i s suitable only to 1500 p . s . i . a . i n t e r n a l pressure; however^if t h i s l i d were replaced by one whose minimum thickness were \ in., as was done f o r t e s t i n g purposes, the equipment could be used safely at pressures up to 5000 p . s . i . a . Sampling Tube Assembly The sampling tube assembly was constructed from 316 stainless steel pressure tubing 9/l6 i n . i n outside diameter and 5/l6 i n . i n inside diameter-. The assembly was divided i n two sections, joined by a 9/16-in. by 9/16-in. by •5--in. tubing tee, and the two ends of the joined sections terminated i n 9/l6-in. by -5-in. by.^-in. tubing tees.  The assembly had an o v e r a l l length  of 19 i n . and was connected to the equilibrium c e l l through valves at three points.  One length of -5-in. tubing connected the top of the sampling assembly  to a point on the c e l l 1-5- i n . below the l i d .  Since the bomb cap extended  below t h i s point on the bomb, a hole was d r i l l e d through the cap to allow the tubing and gland nut to pass through.  A second length of i j - i n . tubing  connected the middle tee (located 12 i n . from the top of the assembly) to a point on the c e l l 5/8 in- from the top.  A t h i r d length of tubing connected  the bottom of the assembly to,a point 3/8 i n . above the bottom of the equilibrium cell.  The valve i n each l i n e was positioned so that i t lay. below the  corresponding bomb connection, and therefore, i f the tubing connecting the valve to the bomb was once f i l l e d with mercury, i t would remain f u l l as long as the valve was not opened. High Pressure Equipment Company Model "30-11HFV' t e f l o n packed, nonrotating-stem valves were used i n the three £-in.  tubing l i n e s connecting the  1-15  c e l l to the bath.  Since the valves were located i n the bath, they were opened  or closed by means of extensions on the valve stems.  Constant Temperature Bath  The constant temperature bath i n which the equilibrium c e l l was immersed was 28 i n . i n diameter, 30-in. high and constructed from 12-gauge, 3l6 s t a i n l e s s s t e e l sheet metal.  In order to reduce heat losses from the  bath, the top, bottom, and sides were a l l insulated. with a 4-in.  The sides were covered  thick layer of glass wool which i n turn was covered with a ^ - i n .  thick layer of a powdered asbestos and portland cement mixture.  A f i n a l layer  of cotton canvas was glued to the asbestos and then painted to give an o i l resistant f i n i s h .  The bottom of the bath was also covered with a k-ln.  thick layer of glass wool, and.this layer was held i n place with a plywood frame.  At those-locations i n the sides and bottom where tubing passed through  the bath wall,to the equilibrium c e l l , small sections were cut from the i n s u l a t i o n and packing glands were f i t t e d into the wall. The top of the bath was covered with an insulated l i d .  This l i d  was used both to support the i n s u l a t i o n and to prevent fumes from the hot o i l escaping into the room.  I t was made from lengths of 1-in. mild s t e e l tee  sections welded together at r i g h t angles, base down, so as to form a web with the same o v e r a l l shape as the bath.  The ends of the tee sections extended  out over the insulated sides of the bath to act as supports.  A 1-in.  deep ring,  7/8 i n . l e s s i n diameter than the inside diameter of the bath, was welded to the underside of the tee sections.  This ring was used.to give r i g i d i t y to the  web and, when wrapped with two lengths of ^--in. braided jute rope, acted as a splash seal f o r the l i d .  The spaces between the uprights of,the tee sections  were f i t t e d with 12-gauge mild s t e e l plates.  These plates were bolted to the  base of the tees and then covered with shaped sections of glass wool i n s u l a t i o n  1-16 h i n . thick. The use of a l i d of t h i s type offered a considerable advantage one formed from a single piece.  over  Access to any p a r t i c u l a r part of the bath was  possible simply by removing the appropriate insulation block and plate.  The  sub-divisions also permitted many d i f f e r e n t pieces of equipment to be i n d i v i d u a l l y f i t t e d and withdrawn. The bath, when i n use, was f i l l e d with a high temperature  lubri-  cating o i l . When t h i s o i l was heated above 200°C very unpleasant fumes were ?  produced, and i t was found necessary to vent the bath.  A vent of 2-in.  galvanized s t e e l drain pipe ran from the bath l i d to the roof of the building. An a i r i n j e c t o r i n the vent was found to provide  ample draft to remove the  fumes. Heat could be supplied to the bath by means of three heaters or v  removed from i t with a cooling c o i l .  Two of the heaters, both rated at 230  v o l t s and 2500 watts, were threaded into the bath from the bottom.  The t h i r d  heater, rated 110 v o l t s and 1000 watts, was hung from one of the plates i n the top of the bath.  The cooling c o i l was formed from a single•length of 3/8-in.  diameter copper tubing which was c o i l e d so as to l i e along the side of the bath over about 2/5 of i t s circumference.  The c o i l was located i n t h i s manner i n  order that the bomb support could be i n s t a l l e d or removed without copper tubing.  removihg^,the  The two ends of the tubing passed out of the bath bottom through  packing glands and then to the water supply and drain.  The c o i l was purposely  formed from a single length of tubing so that there would be no p o s s i b i l i t y of a water leak into the hot o i l with the resultant rapid generation of steam. A ^--horsepower Greey "Lightnin Model S-2" s t i r r e r driving a shaft f i t t e d with two 3-bladed s t i r r e r s provided adequate s t i r r i n g .  1-17  Temperature Control of the Bath  The temperature  of the hath was regulated with a control c i r c u i t  (shown i n Figure 1-3) i n which the sensing element was a Leeds and Northrup 25-ohm platinum "thermohm".  The thermohm was connected to a Leeds and Northrup  •"Model No. 8067" Mueller Bridge, and the resistance that t h i s sensing element would "have had i f the bath were -at the desired temperature bridge d i a l s .  was set on the  The out-of-balance signal r e s u l t i n g from any difference between  the actual and the desired resistance of the thermohm was fed from the bridge to a Leeds and'Northrup D.C. null.detector.  In t h i s c i r c u i t , the n u l l • i n d i c a t o r  was used only as a D.C pre-amplifier and the amplified signal was sent to,a Leeds and Northrup•"model 6000 Speedomax" recorder-controller.  The control  c i r c u i t on the Speedomax was set so that the control point was zero voltage input.  The control switch was thus opened or closed depending upon whether  the input signal was p o s i t i v e or negative.  A lead from a 110-volt l i n e was  fed through t h i s switch to a 110-volt AC, 6-volt DC r e c t i f i e r which i n turn supplied the a c t i v a t i n g current f o r a "heavy duty mercury relay.  The relay  was used to open or close the l i n e from an autotransformer to one of the 220volt,,2500-watt  heaters.  The other two heaters were s u p p l i e d w i t h power  from autotransformers as well, but only the f i r s t one was operated through the relay.  When the c o n t r o l c i r c u i t was operating, one of the '"steady-on" heaters  was adjusted through, the autotransformer so as to supply most of the-heat input, and the "off-on" heater so as to•supply only a small f r a c t i o n of the total,lead. The autotransformers used to adjust the power supplied to the three heaters were mounted on a common panel board.  Included as w e l l on t h i s panel  board were either a voltmeter or an ammeter or"both f o r each heater, i n order that an estimate could be made of the power being supplied, and a panel l i g h t  TEMPERATURE CONTROL CIRCUIT  Figure 1-3  1-19 .to indicate whether or not the control heater was on. It was found possible, with the c i r c u i t described above, to control the bath temperature.at a point near the equilibrium c e l l and about 12 i n . from the sensing thermohm to within +.01°C. of the set point.  However, the  temperature v a r i a t i o n could be kept within these l i m i t s only with very c a r e f u l adjustment of the bath heaters, and therefore variations of up to +.02°C were allowed.  The accuracy of the temperature control was also affected by changes  i n room temperature.  One of the units i n the control c i r c u i t was sensitive to  temperature changes, and over a period of s i x or seven hours, a set point d r i f t of up to .1°C. would sometimes occur.  Because of the p o s s i b i l i t y of  t h i s d r i f t , no phase e q u i l i b r i a measurements were made unless a frequent check chowed that the set point temperature had remained within +.03°C of the desired value f o r at least one hour.  Temperature Measurement The temperature of the bath was measured with a "Model 8l62",  serial  number 16931^ Leeds and Northrup platinum resistance thermometer suspended from the bath l i d at a point about 2 i n . away from the equilibrium c e l l .  A  c a l i b r a t i o n report, issued by the National Research Council of Canada on October 26, 1959,  w a  s used to convert the thermometer resistance, as measured  on a Leeds and Northrup "Model 8067", s e r i a l number 16931^ Mueller Bridge, to a temperature reading i n degrees Centigrade.  (The thermometer was issued with  a report rather than a c e r t i f i c a t e as the p u r i t y of the platinum wire was found, by the National Research Council, to be less than that specified i n the International Temperature Scale of 19^8.)  The value of the-ice point  resistance, used i n the conversion of the thermometer resistance reading to a temperature one, was obtained using d i s t i l l e d water i c e . Since the temperature i n the equilibrium c e l l was determined by  1-20 measuring the bath temperature and not that of the c e l l d i r e c t l y , a check was made to see how c l o s e l y the two agreed.  Eight iron-constantan thermocouples  were strapped to the bomb at the 'locations shown i n Figure I-kA, the bath heated to approximately. 150°C., and the temperature of the bomb measured using the thermocouples.  The bath was then cooled, some of the thermocouple positions  changed to those shown i n Figure I-hB, and the bath reheated to approximately 150 C  Once the thermocouple temperatures lhad been read, the bath was heated  to approximately 200°C,  and the readings repeated.  Further readings were  made .at 250°C. The four sets of readings obtained are given i n Table I - l . The values given i n Table I - l are not quoted to show the range of temperature v a r i a t i o n over a control cycle, as the control device used when they were measured was an e a r l i e r design much i n f e r i o r to that f i n a l l y  used,  but to give the temperature v a r i a t i o n over that part of the bomb occupied by the equilibrium c e l l , and to compare the c e l l temperature to the temperature at the point where the thermometer i s located.  While the thermocouples were  not c a l i b r a t e d , they were a l l cut from the same length of wire, and the junctions were a l l s i m i l a r l y made.  On t h i s basis i t i s u n l i k e l y that the  c a l i b r a t i o n of the eight thermocouples would be very d i f f e r e n t . TABLE I - l RESULTS OF TEMPERATURE SURVEY OF EQUILIBRIUM CELL Bath Temperature approximately 150°C Thermocouple Number  1 2 3  k  5 6 7 8  Thermocouples p o s i t i o n A  Reading  7.8905 7.8886 7.8960 7.8959 7.8960 7.8959 7.8965 7.8970  (millivolts)  - 7-8935 - 7-8916 - 7-8976 - 7.8976 - 7.8981 - 7-8987 - 7.8980 - 7-8995  1-21  8*-  i_jr 8 3C6  !  3X  ><4  3>C  POSITION A  THERMOCOUPLE  POSITION  I  X4  POSITION B  FOR  TEMPERATURE  Figure I-k  SURVEY  1-22 Bath Temperature approximately 150 C. Thermocouple Number 1 2 3 4 5 6 7 8  Thermocouples p o s i t i o n B  Reading ( m i l l i v o l t s ) 7.8855 7.8840 7.89OO 7.8895 7.8905 7.8905 '7.8910 7.8905  ?emperature approximately 200°C Thermocouple Number  - 7.886O - 7-8850 - 7.8912 - 7.892O - 7-8915 - 7.892O - 7.8916 - 7-8915  Thermocouples po  Reading ( m i l l i v o l t s )  IO.969O•-  1 2 3 4 5 6 7 8  IO.968O .10.9795 IO.979O IO.976O IO.9765 IO.976O 10.9765  Bath Temperature 250°C.  Thermocouple p o s i t i o n B  Thermocouple Number  Reading ( m i l l i v o l t s ) 13.5221 13.5230 13.5220 13-5155  5 6 7 8  10.9720 IO.97OO - IO.98IO - IO.9815 - 10.9770 - IO.9785 - IO.9775 - 10-9775  (avg.)  Over the temperature range considered i n Table I - l , .054 m i l l i v o l t s i s equivalent to about 1°C  As can be seen from the tables, the surface  temperature of the bomb atl50°C. was e s s e n t i a l l y uniform from the bottom of the equilibrium cell,and was equal to that of the o i l bath where the platinum thermometer was located.  At 250°C, a temperature gradient of about 0.1°C  existed between the top of the cap and a point just below the top of the equilibrium c e l l , and the temperature was uniform to within 0.02°C. over the  t-23  rest of the c e l l .  As a result of this test, i t was f e l t that i t was unlikely  that measuring the bath rather than the bomb temperature would result in a significant error when reporting the temperature to 0.1° C., as long as the top of the bomb was covered with bath fluid. Measurement of Pressure The pressure in the equilibrium c e l l was measured with one of two Heise Bourdon tube pressure gauges.  The f i r s t gauge, serial number H21870,  was used for the pressure range 0 to>150 p.s.i.g.  It had a 12-in. face, with  0.2 p.s.i- divisions, and was stated by the manufacturer as being accurate to within +.15 p.s.i.  A calibration obtained from the manufacturer for this  gauge i s given in Table 1-2 and a similar one obtainedby the author near the completion of this research,using a Barnett dead weight tester model number MKT serial number 0131^ is given i n Table 1-3. The second gauge, serial number H21869, was used for the pressure range 150 t o l 5 0 0 p.s.i.g.  It was the same  size as the f i r s t gauge, and the face was divided into 2 p.^s.i. intervals. The accuracy was stated by the manufacturer as being + 1.5 p.s.i. and calibrations similar to those for the other gauge are given in Tables I-h and 1-5-  TABLE 1-2 CALIBRATION SUPPLIED BY MANUFACTURER; FOR HEISE PRESSURE GAUGE N0.2187O  Dead Weight or Mercury Column Reading  Gauge Deviation from Dead Weight or Mercury Column  7.5 p.j.t. 15 22-5 30 37-5 45 52.5 60 67.5 75 82.5 90 97-5 105 112.5 120 127-5 135 142. 5 150 Maximum Hysteresis 1-5 p.s.i. Corrections are noted where error i s 1-5 p.s.i. or more  — —  -----—  --  -—  -—  --  --—  --  1-25  TABLE 1-3 CALIBRATION' DETERMINED USING A BARNETT DEAD WEIGHT TESTER MODEL NUMBER MKT SERIAL NUMBER 0131  Dead Weight Reading 11 P.5.U , 21 . 31 • hi  - 51 61 71 81 91 101 111 121 131  lUl  Gauge Deviation from Dead-Weight Reading Increasing - Decreasing 0 - 0.2 0.05 - -3 0.0 - 0.2 0.0 - 0.2 0.0 - 0.3 .0.15 - 0.3 0.2 - 0.3 0 - 0.2 0.05 - 0.2 ,0.3 0.3  IL9  Corrections are indicated where error i s more than  .15 p . s . i .  1-26  TABLE 1-4 CALIBRATION SUPPLIED BY MANUFACTURER?". FOR HEISE PRESSURE GAUGE V  No. 21869 Dead Weight or M =ury Column Reading .  Gauge Reading (Deviation from Dead Weight or' Mercury Column)  erc  75  150 225 300 375 450 525 600 675 750 825 ,900 975 1050 1125 1200 1275 1350 1425 1500  p.s.i.  — ----  — —  --  —  ---  — \  ----  —  --  — —  Maximum Hysteresis 1.5 p.s.i: Corrections are noted where error i s 1.5 p.s.i. or more  1-27  TABLE 1-5 CALIBRATION DETERMINED USING A BARNETT DEAD WEIGHT TESTER MODEL NUMBER MKT SERIAL NUMBER 0131  Dead Weight Reading 200  300 Uoo 500 600 700 800 900 1000 1100 1200 1300 1U00 1500  Gauge Deviation from Dead .Weight Reading  P-S.L.  --  —  --  --  -— — — -—  Corrections are indicated vhere error i s more-than 1.5 p.s.i. Maximum Hysteresis 1.5 p.s.i.  1-28 Associated Glassware  Associated with the equipment described above were f i v e a u x i l l i a r y glassware unite.  The f i r s t of these units was e s s e n t i a l l y a vacuum manifold  which was connected, through a cold trap, to a mercury d i f f u s i o n pump. The pressure i n the manifold could be measured with a mercury-filled McLeod gauge which was connected to the manifold through a high vacuum stopcock. The second of the glassware units, which was based on apparatus described by Kay and Donharn^.^, 'was designed to.remove dissolved gas from •the solvents to be studied'in the equilibrium c e l l .  A diagram of the unit  i s given i n Figure 1-5- I t consisted of seven glass vessels (F 1 to 7), each k.5 cm. i n diameter and 33 cm. long, and each connected•through a-high vacuum stopcock to an 8-mm. tube.  This tube was joined i n turn to ,the  vacuum manifold. The p a i r s of vessels F 2 and F 3, F k and F 5, and F 6 and F 7 are  f u n c t i o n a l l y associated with the 1 - l i t r e round bottom flasks F 10, F 9,  and F 8 respectively.  Each functional group was used f o r one material.  Vessel F 1 was used i n common f o r a l l materials. Solvent was i n i t i a l l y added to a 1 - l i t r e f l a s k ( f o r example, F 10) and the f l a s k was then connected .through a Quickfit and Quartz "CCB19" ground mercury sealed cup cone and socket j o i n t to one of the vessels ( f o r example, F 2).  The l i n e j o i n i n g ,the two pieces contained an 8-turn c o i l , 8 cm. i n  diameter f o r f l e x i b i l i t y ^ a n d a high vacuum stopcock. The t h i r d glassware unit was used to store deaerated material from the  transfer apparatus before, i t was introduced to the equilibrium c e l l . A  diagram of t h i s f l a s k i s given i n Figure 1-6.  I t consisted of a 30-cm. high  • double-walled f l a s k whose outer and inner walls were formed from tubing 7U-mm. and 36-mm. i n diameter respectively.  The annular space was connected at  MERCURY SEALED UNGREASED STOPCOCK  FLASK MERCURY  STORAGE  FLASK  Figure 1-6  1-31  the top, through an ungreased mercury-sealed stopcock S ' 1 3 , to the-common transfer vessel F 1 , and, at the bottom, through a mercury-cut-off S I , to a glass-to-metal kovar seal.  valve  This seal was used to j o i n the glass  l i n e from the storage chamber to a length of -j^-in. metal tubing and the high pressure valve V 4 connected to .the top of the equilibrium c e l l . The fourth of the glass a u x i l l i a r y u n i t s , shown i n Figure 1 - 6 , was used as a mercury storage reservoir f o r the High Pressure Equipment Company Incorporated "model 6 2 - 6 " mercury pressure generator. high glass vessel J made'from 5 1 - ™ i -  I t consisted of a 17-cm.  tubing, connected at the top to the high  pressure side of the mercury d i f f u s i o n pump and at the bottom through a glass c o i l to a glass-to-metal kovar seal. high.pressure  This seal was i n turn connected to a  valve V 4 which could be used to i s o l a t e the reservoir from the  pressure generator.  The glass c o i l was included to prevent any stress being  placed on the kovar seal as the volume, and thus weight, of mercury, i n the reservoir was changed.  Mercury could be added to the r e s e r v o i r through a  glass side arm connected near the top of the reservoir. through a-barometric  The side arm was joined  leg to the bottom of a short length of 22-mm. glass tubing H.  Mercury could be poured into t h i s tubing, through a funnel formed from a ground glass socket, and then transferred through the barometric  leg to the mercury  reservoir by atmospheric pressure. The f i n a l glassware u n i t , shown i n Figure 1 - 7 , was used to c o l l e c t samples from the pressure sampling tube assembly D i n the bath. of three small f l a s k s connected i n p a r a l l e l .  I t consisted  The l i n e j o i n i n g the f l a s k s was  connected through a kovar glass-to-metal seal and valve V 1 3 to the sampling tube assembly and, through a mercury c u t - o f f valve S 1 2 , to the vacuum manifold. Each of the f l a s k s was joined to the common l i n e through a Q u i c k f i t and Quartz mercury sealed " C C B 1 9 " cup cone and B19 socket j o i n t i d e n t i c a l to those used on the o n e - l i t r e solvent f l a s k s described e a r l i e r .  The nature of these greaseless  1-32  S 12 ACUUMI MERCURY CUT-OFF VALVE  M MERCURYSEALED GROUND GLASS JOINT  TO PRESSURE SAMPLING TUBE rh  GLASS TO  L-H  METAL SEAL  LIQUID SAMPLE COLLECTION TUBE VAPOR SAMPLE COLLECTION TUBE K  SAMPLE  COLLECTION  TUBE MERCURY  Figure 1-7  TRAP  1-33 vacuum t i g h t j o i n t s allowed each f l a s k to be e a s i l y removed or replaced and, since the j o i n t was not lubricated,  there was no p o s s i b i l i t y of the samples  becoming contaminated with stopcock grease. The f i r s t of the-three flasks, Flask K, was used as a mercury trap. It was made from 17-mm. tubing approximately 5 i n - long and was located d i r e c t l y below the kovar seal. The second of the f l a s k s , Flask L, was used to c o l l e c t vapor samples. It was approximately 10§- i n . long and was formed from two sizes of tubing. The top k i n . were of 19-mm. tubing and the'bottom 5? i n - of either 6-mm.,^8-irkrrr,; or 10-mm. tubing, depending upon the size of vapor sample to be  collected.  The t h i r d f l a s k , Flask M, was used to c o l l e c t l i q u i d samples. similar i n shape but longer than the second.  It was  The top portion was of 19-mm.  tubing 5 i n - long and the bottom of 10-mm. tubing 8 i n . long.  1-3^  Figure 1-8  1-35  Figure 1-9  Figure I-10  Figure 1-11  1-38  Figure 1-12  1-39  Figure 1 - 1 3  MILD  S T E E L - ONE PART  NUMBER  REQ D 7  0 0 2 5 , - 0037  —5-°  \  - 3 7 7 " + 0 0 2 + 004  J  H-i-h  R-4 •FLATS  N F THREAD  FOR  _l£ , !2 TPt  WRENCH  air i 304  STAINLESS ONE  DETAIL PARTS  DRAWING  NUMBER  NUMBER  b, 6, a 7  2  PART  STEEL -«4-  REQ'D NUMBER  5  MILD  S T E E L - ONE R E Q ' D PART  NUMBER ALL  iCALE  » i.'LL r  SIZE  DW  6  DIMENSIONS  IN  INCHFS  8/6/61  Figure I-lk  I o  J- N C T A P - 6 SPACED  NC ON  ON  CIRCLE  HOLES  EQUALLY  SPACED  CIRCLE  CENTRE  DIAMETER  OF THESE  THROUGH HOLES  EQUALLY  TAP - 2  3 INCH  LINE  HOLES 4-JflNCH  CENTRE  ON P A R T  HOLES  MUST  LINE NUMBER  OF  PASS  LOCATING  I  \--Z3i .-y 003, - 0 0 0 —^ a  i_  T  - 2 5 0 " . + 003,- 0 0 0 -  Y77ZZZA  / 3 MILD  STEEL  PART  -  ONE  NUMBER  STEEL  PART  DRAWING  PARTS  i-ti-E  - FJI.L  NUMBER  SIZE  NUMBER  8  DW  8  THREAD  9 MILD  DETAIL  N F  REQ ' D  -  ONE  NUMBER  REQ  0  8  3  9  9/6/61  Figure 1-15 !  t— 1  CUT  WIDTH  LESS  THAN  ^  -CLEARANCE BOLT - 6 SPACED  i  BREAK  BOTH  INNER  SPLIT MILO  AND OUTER  RING  CORNERS  CLAMP  S T E E L - ONE R E Q ' D PART  NUMBER  TO  1, Jr --1*7 — t 7 1 ,. 1 .BREAK  ON 4 ^  TO  STEEL  ^-INCH  J  1  PART  FOR  EQUALLY PDC  4  CORNER  MILD  HOLE  HOLES  ^  - ONE R E Q 'D  NUMBER  II  10  DETAIL PARTS SCALE  DRAWING NUMBER  •  FULL  SIZE  10,  NUMBER II, 12, DW  8  5 13  22/6/61  I  SECTION  A  |  »  C  THREAD  l°-  •J  1 ° -  ^1  oso!  STAINLESS  V VTS O  STAINLESS ONE PART  STAINLESS ONE PART  ONE  STEEL  PART  REQ'D  NUMBER  STEEL  REQ'D NUMBER 18  17  STEEL  REQ'D NUMBER 16  A  1-  JJ.iL  -J U  075  STAINLESS ONE  TEFLON-ONE  STEEL  PART  REQ'D  REQ'D  NUMBER 22  PART NUMBER 19  k—2~H 8  PART NUMBER  23  '  T  LU • a  H  1  STAINLESS ONE  ALL PARTS PART  DIMENSIONS  IN  16 -  FULL  PART  INCHES  17,18, 19, 2 0 , 2 1 , 2 2 , 2 3 - T W I C E  FULL  4-48  u 1 2 I*  TEFLON - ONE REQ'D  4°  -J  THREAD  t STAINLESS STEEL - THREE REQ D PART  NUMBER 21  1  STEEL  REQ'D  NUMBER 20  DETAIL PARTS  DRAWING NUMBER NUMBER  6  16 - 23  SIZE SCALE  SIZE  Figure 1-18  AS  NOTED  DW  12/6/61  o  ^ L I-7U-  G E ALNICO MAGNEL N O 2 2UI8B F -ORCE FIT  V  GROOVE FOR 020° N C IHROME RN IG CLAMP T W O GROOVES 310 N ICHES APART  16  STAINLESS  STEEL  ONE REQ'O PART  NUMBER 26  -8 - 32 THREAD  ran"  SHAFT  OF STAINLESS  STEEL  -  PART  -HFE  i_  ONE REQ'D  NUMBER  28  STAINLESS ONE PART  STEEL  REQ'D NUMBER  30  F 37S. g STAINLESS  STEEL  ONE REQ'O PART NUMBER  STAINLESS ONE  27  STEEL  REQ'O  PART NUMBER 29 STAINLESS  WR IES SPOT WELDED TO VANES AND TOGETHER PART  ONE PART  STEEL  REQ'D NUMBER  31  NUMBER 25  STAINLESS STEEL - ONE REQ'O STIRRER VANES  ALL DM I ENSO INS IN N ICHES  DETAIL  PARTS 25, 26, 28 - FULL SIZE PARTS 27, 29, 30, 31 - TWC IE FULL SIZE Figure I-19  PARTS  DRAWING NUMBER 7 NUMBER  25 - 31  SCALE AS NOTED D W 13/6/61  Si  Pt-I  j^TAP- 2 HOLES FROM BOTTOM  ft  I  — (! -0016, -0025 HIGH TENSILE STRENGTH ALLOY STEEL ONE  PART NUMBER  STAINLESS STEEL ONE REQ 'D  REQ 'O 62  Jl , ^ 1  — 377 - 0025 - 0037  PART  S3  STAINLESS  MONEL  STEEL  ONE REQ 0 1  L_isaJ  NUMBER 23  5  PART NUMBER 68  METAL  ONE REQ D 1  PART NUMBER 36 DETAIL  ALL DM I ENSO INS N I N ICHES  PARTS 23, 62 • FULL SIZE PARTS 36, 68 - TWC IE FULL SIZE Figure 1-20  DRAWING NUMBER 8  PARTS NUMBER  23, 36, 62, 68  SCALE AS NOTED D W 22/6 SI H i  Figure 1-21  1-49  Figure 1-23  DETAIL  DRAWING NUMBER 12 50, 51, 52. a 53  PARTS NUMBER -CLEARANCE HOLE FOR 10-24 SCREW 6 REQ'D DN 2 j | P D CIRCLE  SCALE  • FULL SIZE  DW  16/6/61  -10-24 TAP - 6 HOLES -|- DEEP 13 SPACED ON 2-j§D  EQUALLY  , 13  CIRCLE  -Hi  2 4409 2 4421  rjzzz  -0591" —  2 165 2 441  2 165  Ha  PART  NUMBER 53  MILO STEEL - ONE REQ'D  COUNTER  ^"f  TT 32 TPI  PART NUMBER 52 MILD STEEL - ONE REQ'D  N C TAP  SINK FOR  FLATHEAD  PART NUMBER 51 MILO STEEL - ONE REQ 'D  SCREW 32 • "  TPI  PART NUMBER 50 MILD S T E E L - ONE REQ D  r-  1ft  MACHINE  KEYWAY  IN  WORM  WORM ONE  REQ'D - MILD STEEL  GEA  GEAR  PART NUMBER  93  PART NUMBER 94  PARTS  84.  88,  94 -  PART  93 - FULL  ALL  DIMENSIONS  TWICE  FULL  DETAIL DRAWING NUMBER  SIZE IN  SIZE  INCHES  PARTS SCALE  13  NUMBER  84, 88, 93, 94  AS N O T E D  D W  I9/6/6I  H I  H  -CLEARANCE \  CLEARANCE 4 HOLES  HOLE  FOR 8-32 TAP  4 - HOLES  HOLE FOR 6-32 TAP  I 850  X^  'i—lit  6 69  I—L  NUMBER 85  t  PART NUMBER 89  MILD STEEL - ONE REQ'D 3936 MIN 3939 MAX  —  1  -1*1PART  1  9056  -  — I 614  MILD STEEL - ONE REQ'D  -  —  i  —  •  _  PART NUMBER 91 MILD STEEL - ONE REQ'D  PART  NUMBER  DETAIL  86  MILD STEEL - ONE REQ ' D  PARTS 8 6 , 91 - TWICE PARTS 85, 89 - FULL  Figure 1-26  FULL SIZE SIZE  DRAWING  PARTS  NUMBER  SCALE  AS NOTED  NUMBER 15  65, 86, 89,8 91 D W  21/6/61  I  vn ro  PART LAMINATED  NUMBER BAKELITE  75 PLASTIC  PART MILD  NUMBER  S T E E L  -  ONE  77 R E Q ' D  PART MILD  NUMBER  S T E E L  -  ONE  7 8 R E Q ' D  SPLINED PART BRONZE  DETAIL PARTS  SCALE  Figure 1 - 2 7  SHAFT  NUMBER -  ONE  49 REQ'D  DRAWING  NUMBER  • FULL  49,  SIZE  NUMBER 75, 7 7 ,  D W  14 8  78  2C/6/6I  M I  VJl V>J  APPENDIX II - DETAILS OF PROCEDURE  Il-i  Cleaning of Equipment  The apparatus was thoroughly cleaned a f t e r i t was assembled and before i t was used.  I n i t i a l l y , at least s i x ^ - - l i t r e volumes of hot water i n which  detergent had been dissolved were forced through each l i n e and f i t t i n g (with the exception of the associated glassware).  These detergent washes were  followed by a thorough tap water rinse. The rinse water was removed with several technical-grade acetone washes, and the equipment was then washed with three l o t s of technical-grade benzene, and f i n a l l y with three l o t s of o n c e - d i s t i l l e d , technical-grade acetone. Following each of the acetone washes, dry nitrogen was blown through the l i n e s . After the f i n a l acetone wash, the entire apparatus was purged with nitrogen, and f i n a l traces of solvent were removed by evacuating the equipment f o r several hours using the d i f f u s i o n pump. The glassware was cleaned before assembly.  Each component was placed  i n a bath of b o i l i n g water and detergent f o r several minutes and then thoroughly rinsed with tap and d i s t i l l e d water.  The rinse water-was removed by oven drying,  and any moisture introduced when the components were joined together was removed by prolonged evacuation of the completed  unit.  Introduction of Mercury and D e f i n i t i o n of Pressure Gauge Zero Once the assembled equipment had.been cleaned, i t was evacuated f o r 2k hours.  The mercury storage f l a s k J (Figure l ) was then f i l l e d with mercury  from the funnel H.  During the transfer of mercury from the funnel to the  f l a s k , the top of the f l a s k was connected to the vacuum pump so that any a i r which had been dissolved i n the mercury would be pumped o f f . When the f l a s k was f u l l , valve V 1 1 was opened and the mercury was allowed to run into the system.  This procedure was repeated u n t i l the entire apparatus, with the  exception of the equilibrium c e l l and the glass units, was f i l l e d .  II-2 Since the pressure gauges F and G were supplied"hy the manufacturer with an undefined zero, i t was necessary to choose a r b i t r a r i l y a value f o r zero pressure.  This a r b i t r a r y zero value was defined i n the following manner.  Mercury was introduced to the equilibrium c e l l A u n t i l the l e v e l was at a point 1 cm. above the lowest tubing connection to the bomb.  The measuring head rod  was then positioned so that the detecting wire was at the l e v e l of the interface, and the height of a graduation on the measuring head rod was read on ; a scale located beside the rod.  This scale reading was found to be 2.4 cm.  c e l l was next opened to atmospheric to read zero.  The  pressure and the pressure gauge scales set  Zero pressure f o r the gauges was therefore defined as that  pressure exerted by a column of mercury i n the equilibrium c e l l which  corresponded  to a reading of 2.4 cm. on the measuring head rod scale when the pressure i n the c e l l above the mercury was the same as that on the outside of the gauge. Since t h i s method of locating the gauge zero required that the c e l l be open to the atmosphere, and since i t was impossible to allow a i r into the c e l l when using the equipment, a secondary c a l i b r a t i o n point was defined which could be used to check the p o s i t i o n of the gauge scale.  The mercury l e v e l i n  the mercury storage f l a s k J was adjusted to an a r b i t r a r y reproducible l e v e l a n d ?  the f l a s k was connected to the gauges through valves V 6, V 7, V 9, V 11. The gauge pressure corresponding to t h i s l e v e l of mercury i n the f l a s k was read and recorded.  The gauge zero could then be checked at any time simply by adjusting  the mercury l e v e l i n the storage f l a s k to the 'correct p o s i t i o n and comparing the gauge reading with the value i n i t i a l l y obtained. made, of course, f o r any change i n atmospheric  A correction had to be  pressure from that at the time  when the i n i t i a l value was obtained. Conversion of Gauge Reading to Absolute Pressure i n the Equilibrium C e l l Three corrections must be applied to the value read on the pressure  H-3 gauges before the pressure i n the equilibrium c e l l can be obtained. 1. Correction f o r atmospheric  pressure  The pressure as read on the gauges was the difference between the gauge i n t e r n a l and external pressures.  Atmospheric pressure therefore had to  be added to the gauge reading to convert i t to an absolute reading. Atmospheric pressure was read from a Precision Thermometer and Instrument Co. "Princo F o r t i n Type" barometer and was corrected.for temperature and gravity, using correction tablesr:supplied by the manufacturer. 2. Correction f o r the v a r i a t i o n of the mercury l e v e l inside the equilibrium cell The gauge reading was a function of the mercury l e v e l i n the equilibrium c e l l , and therefore a correction .had to be made f o r any v a r i a t i o n of t h i s l e v e l from i t s "zero p o s i t i o n " .  I f the mercury l e v e l was above the  zero value of 2-k cm., the pressure corresponding to the extra height of mercury had to be subtracted from the pressure reading, and i f the l e v e l was below-the 2.k cm. l e v e l , the correction term had to be added. ;  3- Correction f o r change of mercury density with temperature The l i n e connecting the gauges to the equilibrium c e l l could be considered to be a mercury U-tube, and since bothtarms of the U-tube were at the same temperature when the gauge zero was defined, a correction term had to be applied i f the temperature,  and thus mercury density, were not the same i n  both arms when a pressure reading was made.  For the purpose" of c a l c u l a t i n g  t h i s correction, the arm on the c e l l side could be divided into three sections: one section 36 cm. long, located inside the bath and therefore at:the bath temperature;  one section 11. h cm. long, enclosed by the bath insulation, and  therefore at a temperature intermediate between that of the bath and the room (this intermediate temperature was assumed to be the average of the room and  II-4 the hath temperature); and a f i n a l section at room temperature.  Since the  f i r s t two of these sections were always hotter than the arm connected to the gauge, the correction f o r the decrease i n mercury, density was added to the gauge reading. The resultant correction was the sum of the three discussed above. Let P ^ a  = absolute pressure i n equilibrium c e l l i n mm.  s  of mercuty P gauge P -k , a  = atmospheric pressure" i n mm. of mercury  m  5  -^bath  5 avg.  = density of mercury at 0° Centigrade  o  5 room  1  gauge reading i n mm. of mercury  =  =  =  over  ^ ^ s ^ y °^ mercury at room temperature  =  (  ^  e n s  ^ y °^ mercury at the bath temperature  density of mercury at the average value of i the  a  t  room and bath temperature  = height of mercury -level i n mm. as measured on the measuring head rod scale  t  h  e  n  P  abs.  =  P  gauge  +  P  atm. + <  + 36O -9 room 5> 0  a  " ^  _ ^ t h  ( l - 5*bath ^ 5>room /  + 114 -P room 5* 0  / 1 - Savg \ J>room/  Introduction of Materials Materials to be studied were introduced to the system through the o n e - l i t r e solvent flasks shown i n Figure 1 and Figure 1-5 • One f l a s k was used for each material.  Since a common procedure was followed with each substance,  only.that used f o r methanol w i l l be described.  A few grams of " D r i e r i t e "  anhydrous calcium sulphate were added to ,flask F 10 and the f l a s k was flushed with dry nitrogen.  A quantity of methanol in.excess of that required was  II-5 added, and the f l a s k was connected.through the ungreased,mercury-sealed cone and socket j o i n t to the l i n e from transfer f l a s k F 2.  The solvent was stored  in the f l a s k f o r at least 2k hours i n order that any moisture picked up during the pouring would be removed.  (Sodium-lead a l l o y was used as the drying agent  for benzene and toluene and the standing time was usually reduced to a few hours.)  The methanol was transferred to f l a s k F 2 by vacuum d i s t i l l a t i o n .  Stopcocks S 3 and S 'U were opened, and the a i r and a small percentage of the methanol pumped out of F 10.  When the a i r had been removed, stopcock S k was  closed and a Dewar f l a s k containing l i q u i d nitrogen was placed around flask F 2.  I f a large amount of methanol were to be transferred, a heating mantle  could be used to warm the methanol f l a s k . After the desired amount of methanol had been transferred (enough methanol was always l e f t i n F 10 to cover completely the drying agent), stopcock S 3 was closed and stopcock S k opened. The space above the frozen methanol was then evacuated u n t i l the pressure, as read at the vacuum manifold, was of the order of 10 the  mm. of mercury.  When  evacuation was completed, the stopcock connecting the transfer f l a s k s to  the vacuum manifold was shut, and the l i q u i d nitrogen.Dewar f l a s k was placed around f l a s k F 3-  The solvent i n F 10 was allowed to melt and then d i s t i l l e d  through stopcocks S k and S 5 "to Flask F 3-  The frozen solvent i n F 3  w  a  s  again evacuated to remove any a i r that might have been trapped i n the solvent during the f i r s t evacuation and was then allowed to melt and vacuum d i s t i l l e d through stopcocks S 5 and S 2 to f l a s k F 1. Once the methanol was present i n F 1, toluene was d i s t i l l e d from F 5 to give a mixture of approximately the desired concentration and with a volume of between 100" and 150 cc.  The frozen solvent mixture was evacuated through -k  S 2 u n t i l the pressure, as measured at the manifold, was less than 10 mercury and stopcock S 2 was then shut.  mm. of  After the mixture had melted, i t was  d i s t i l l e d through the ungreased stopcock S '13 to the intermediate storage f l a s k T.  II-6 This d i s t i l l a t i o n was accomplished by keeping f l a s k F 1 at room temperature and f i l l i n g the centre tube of the intermediate storage f l a s k with l i q u i d nitrogen.  When the d i s t i l l a t i o n was almost completed,  stopcock S 13 was  closed, stopcock S lh opened, and the l a s t small percentage of the mixture rejected.  Stopcock S 13 was then opened and any l a s t traces of a i r removed  from above the solvent mixture. The mixture was transferred'from the intermediate storage f l a s k to the equilibrium c e l l using the mixture vapor pressure as the d r i v i n g force. Stopcock S 13 was shut and the centre tube of the storage f l a s k f i l l e d with hot water.  When the mercury cut-off valve S 1 and valve V k were opened, the  solvent mixture was forced, by the pressure of the vapor above the l i q u i d , into the previously evacuated equilibrium c e l l . The design of the solvent transfer apparatus allowed neither the composition nor the weight of the solvent added to the c e l l to be known. I f the equipment were to be used f o r s p e c i f i c volume measurements, the design would have to be modified.  However, the design used was found e f f e c t i v e f o r  t r a n s f e r r i n g an approximate amount of solvent i n an a i r - f r e e condition. Preparation f o r Measurements Once a solvent mixture was present i n the equilibrium c e l l , valve V k was shut and valves V 6, V 7>  a n  d V 8 opened.  except when used f o r testing^purposes.)  (Valve V 5 a s always open w  F u l l power was supplied to each of  the three bath heaters u n t i l the bath temperature  had reached the desired  value and the 1000-watt heater was then turned o f f .  At t h i s point the o f f -  on heater was switched o f f and the power supplied to the steady-on heater reduced u n t i l the bath temperature  slowly f e l l .  turned on and adjusted so that the temperature c i r c u i t was then turned on.  The off-on heater was then slowly rose again.  The control  II-7 The pressure i n the equilibrium c e l l was noted next, valve V 8 was shut, and the sampling tube assembly was c a r e f u l l y evacuated through valve V 13 and stopcock S 12 u n t i l the pressure as read on the McLeod gauge  -1+ was less then 10  mm. of mercury.  Valve V 13 was then closed, valves V 9 and  V 10 opened, and the assembly f i l l e d with mercury from the pressure generator IJto a pressure of 100 p . s . i . greater than that i n the c e l l .  Valve V ' l was  then opened and 5 cc. of mercury were pumped through the l i n e between V, 1 and the c e l l , i n order to clear i t of solvent and leave the l i n e f u l l of mercury. Valve V 1 was then closed again, the pressure i n the assembly raised to i t s previous value, and V 2 opened.  The l i n e from valve V 2 to the c e l l was purged  i n the same manner as the f i r s t one and V '2 closed.  After both l i n e s had been  purged, valve V 13 was opened to connect the assembly to the vacuum pump, and any solvent which had escaped from the c e l l was removed.  At the conclusion of  the pumping, valve V.13 was closed and the assembly f i l l e d with mercury to the same pressure as existed i n the c e l l .  Valve V 10 was then closed, valve V 3  opened, and the sampling tube, assembly l e f t f u l l of mercury and connected to the c e l l through V 3 u n t i l a sample was taken. The l e v e l of the mercury interface i n the equilibrium c e l l was next adjusted, by the removal or addition of mercury through Valves V 8 and V 9> u n t i l i t lay at least 1 cm. below the l i q u i d sampling port, and at least 1 cm. above the lowest port. generally chosen.  In practice, a l e v e l 1 cm. below the sample port was  When t h i s adjustment was completed, a check was made to see  that the vapor-liquid interface lay between the l i q u i d and the vapor sampling ports.  I f i t was found that t h i s interface d i d n o t . l i e between these two ports,  then either the mercury l e v e l was readjusted or solvent was removed from the cell.  II-8 When b o t h i n t e r f a c e s were a t t h e d e s i r e d l e v e l , t h e magnetic s t i r r e r was t u r n e d on, and a check was made t o see t h a t t h e s t i r r e r was operating.  The c e l l c o n t e n t s were then a l l o w e d a t l e a s t one hour t o come  t o phase e q u i l i b r i a .  Frequent checks were made d u r i n g t h i s time t o see t h a t  the b a t h temperature d i d n o t d r i f t from t h e d e s i r e d v a l u e .  Measurements and T a k i n g o f Samples A f t e r t h e c o n t e n t s o f t h e e q u i l i b r i u m c e l l had been h e l d a t a c o n s t a n t temperature f o r one hour, t h e p r e s s u r e and temperature were d e t e r m i n e d , and samples were t a k e n o f b o t h t h e l i q u i d and v a p o r phases. r e s i s t a n c e o f t h e p l a t i n u m thermometer was measured f i r s t .  The  The gauge p r e s s u r e ,  e q u i l i b r i u m c e l l mercury l e v e l , atmosphere p r e s s u r e , and room temperature were then recorded. When t h e above measurements had been made, a vapor phase sample was t a k e n .  I n o r d e r t o t a k e t h i s sample, t h e sample c o l l e c t i o n tubes were  f i r s t e v a c u a t e d t h r o u g h t h e mercury c u t - o f f v a l v e S 1 2 , and t h i s v a l v e was then closed.  V a l v e V 1 was opened, a l l o w i n g t h e m e r c u r y i n t h e s a m p l i n g tube  assembly t o be r e p l a c e d b y an e q u i v a l e n t volume o f vapor from t h e c e l l , and v a l v e s V.1 and V 3 were t h e n b o t h c l o s e d , . i s o l a t i n g t h e sample i n t h e s a m p l i n g tube assembly.  A Dewar f l a s k o f l i q u i d n i t r o g e n was p l a c e d around  f l a s k L and v a l v e V 13  w  a  s opened.  collection  When t h e sample had d i s t i l l e d from t h e  s a m p l i n g tube assembly and been c o l l e c t e d  i n f l a s k L, t h e l i q u i d was removed  and t h e sample a l l o w e d t o r u n down i n t o t h e end o f t h e c o l l e c t i o n tube.  It  was t h e n r e f r o z e n and t h e tube s e a l e d o f f , w h i l e s t i l l under vacuum, and s t o r e d for later analysis. The c o l l e c t i o n f l a s k s and s a m p l i n g tube were r e - e v a c u a t e d b e f o r e a l i q u i d sample was t a k e n .  V a l v e V 13 was t h e n closed, and v a l v e V 2 opened f o r  a f r a c t i o n of a second,allowing a  little  o f t h e l i q u i d phase t o b l e e d i n t o  II-9  the sampling tube assembly.  Once 'the liquid phase sample had been isolated in  ,the assembly, i t was collected:in flask M, sealed off under vacuum, and stored for later analysis. Further Measurements When one set of equilibrium measurements had been completed, preparations were made for the next. three categories.  These preparations f e l l into one of  If noLfurther measurements were desired.from the material  that was in the c e l l , or i f insufficient material remained, the bomb was evacuated through the sampling tube assembly and the bath was cooled. If, however, additional measurements were required at compositions near to that of the material in the c e l l , the•composition could be changed by bleeding off some of the vapor phase.  The amount of change that could Ibe achieved by  •this method was a function of the shape of the equilibrium.curve for'the materials present and the amount of material in the c e l l , but in the case of the toluene-benzene system,,changes of up to 15 percent' were possible. When equilibrium values were required at more than one temperature from material of the same composition, as was the case with the toluenemethanol system, the f i r s t set of readings were taken at the lowest temperature at which measurements were to be made, and further sets taken simply by raising the temperature.  It was found to be possible, with this latter system, to  introduce initially- enough material to the c e l l to take two sets of readings at each,25° interval from 125 to 250° C. Temperature Limits for the Use of the Equipment *  The equipment was found to be satisfactory, when used with either the benzene-toluene or toluene-methanol system for continuous use at temperatures up to 200° C ; however, i t could not be used, at least with the  11-10 toluene-methanol system, at temperatures higher than t h i s f o r more than a few hours. 250° C  When equilibrium measurements were made at 25° intervals up to  and the equipment coaled immediately after the l a s t reading, no  problem was encountered.  However, at the conclusion of thisJproject, an  attempt was made .to obtain several measurements from one f i l l i n g at 250° C. After the bath had been at t h i s temperature f o r a few hours and a sample of the vapor phase was taken, i t was found that the sample contained enough permanent gas (a gas which was not condensible i n a l i q u i d nitrogen trap) to prevent i t s c o l l e c t i o n by vacuum d i s t i l l a t i o n . resulted  i n the same d i f f i c u l t y .  Sampling of the l i q u i d phase  Whether t h i s gas was produced by the  •decomposition of the solvent material being studied, or of the t e f l o n seals in the equilibrium c e l l ,  i s not known.  However, the f a c t that i t was  produced, presented a d e f i n i t e upper l i m i t f o r the temperature at which measurements could be made, and severely l i m i t e d the number of readings which could be made from one f i l l i n g at temperatures just below t h i s l i m i t .  APPENDIX I I I  III-l  CHROMATOGRAPHIC ANALYSIS OF PURIFIED METHANOL  M e t h a n o l , which h a d been d i s t i l l e d and d r i e d as d e s c r i b e d e a r l i e r , was a n a l y s e d f o r i m p u r i t i e s w i t h a Beckman ."GC2" gas chromatograph.  The  a l c o h o l was t e s t e d u s i n g a s i x - f o o t column o f "8N8 F l e x o l P l a s t i c i z e r " £ 2 - 2 - ( 2 - e t h y l h e x a n a m i d o ) - d i e t h y l d i 2-ethylhexoate_^] on f i r e - b r i c k a t 70° C. No i m p u r i t i e s , w i t h t h e e x c e p t i o n o f one p o s s i b l e t r a c e , were found.  This  column, however, was n o t c o m p l e t e l y s a t i s f a c t o r y f o r d e t e r m i n i n g methanol p u r i t y as i t would n o t s e p a r a t e methanol f r o m w a t e r , a v e r y l i k e l y  impurity.  A s i x - f o o t column o f 2,2,methoxy, e t h o x y - e t h y l e t h e r on f i r e - b r i c k o was t h e n t e s t e d a t 70 methanol and w a t e r .  C ^ a n d i t was f o u n d t h a t t h i s column would s e p a r a t e  When a sample o f p u r i f i e d methanol was used, one i m p u r i t y ,  w a t e r , was f o u n d , b u t t h e water-methanol s e p a r a t i o n was n o t adequate t o e s t i m a t e the  amount o f w a t e r p r e s e n t . A s i x - f o o t , column o f "Carbowax 1000" ( p o l y e t h y l e n e g l y c o l ) on t e f l o n  was u s e d f i n a l l y .  T h i s column gave e x c e l l e n t s e p a r a t i o n , a t 70° C , o f t h e  components i n p r e p a r e d m i x t u r e s o f water, and m e t h a n o l , and o f w a t e r , methanol, and formaldehyde.  Two t e s t s were made w i t h p u r i f i e d methanol u s i n g t h i s  column,  and i n each case t h e o n l y d e t e c t a b l e - i m p u r i t y was w a t e r ; no t r a c e o f formaldehyde was found.  I n t h e ' f i r s t t e s t t h e methanol a n d ' " D r i e r i t e " o v e r w h i c h i t was  afoored were s e p a r a t e d , n o t t o o s u c c e s s f u l l y , b y d e c a n t i n g , and a w a t e r c o n t e n t of  about 0.15 mole p e r c e n t was f o u n d .  I n t h e second t e s t t h e methanol and  " D r i e r i t e " were s e p a r a t e d b y vacuum d i s t i l l a t i o n mole p e r c e n t was found.  and a w a t e r c o n t e n t o f 0.08  S i n c e methanol u s e d i n t h e phase e q u i l i b r i u m s t u d i e s  was  s e p a r a t e d from t h e " D r i e r i t e " b y vacuum d i s t i l l a t i o n , t h e w a t e r c o n t e n t i n  the  methanol u s e d - was \'0 l e s s t h a n 0.1 mole p e r c e n t .  IV-1  APPENDIX IV ANALYSIS OF BENZENE-TOLUENE AND METHANOL-TOLUENE MIXTURES Benzene-Toluene Mixtures  Benzene-toluene  mixtures obtained during the phase equilibrium studies  were analysed using a Beckman "G02"  gas chromatograph.  The chromatograph was  f i t t e d with a six-foot column of "8N8 Flexol P l a s t i c i z e r " ^2-2  -(2-ethylhexan-  amido)-diethyl d i 2-ethylhexoate^ oh f i r e - b r i c k , which had previously been shown to give excellent separation of these two  substances.  Mixtures of known composition were used to c a l i b r a t e the chromatograph and column.  These mixtures were prepared i n four-ml. t e f l o n stoppered glass  weighing b o t t l e s .  A clean dry stoppered b o t t l e was f i r s t weighed on an F.  Mettler "Gram-atic" e l e c t r i c a l balance, then removed from the and p a r t l y f i l l e d with benzene from a hypodermic syringe.  balance,,unstoppered,  After the stopper was  replaced i n the b o t t l e , the weight of the b o t t l e and benzene was measured. Toluene was added to the b o t t l e i n a similar manner,'using a clean syringe, and the weight of the mixture was  determined.  At least three samples from each standard mixture were used to calibrate the chromatograph.  The height of the benzene and of the toluene  peaks were measured on the chromatographic  traces obtained from each sample and  .the r a t i o of the peak heights was calculated.  }  The averaged values of the  results obtained i n t h i s manner f o r each sample were plotted on two For mixtures of more than 50 mole percent benzene, the log  graphs.  of the r a t i o of  moles toluene to moles benzene was plotted versus the log of the r a t i o of the peak height toluene to peak height benzene, and f o r mixtures of less than 50 mole percent benzene, the log of the r a t i o of moles benzene to moles toluene was p l o t t e d versus the log of the r a t i o of peak height benzene to peak height toluene. It was found that the relationship between the peak height r a t i o and  IV-2 the concentration r a t i o d i d not remain constant'but changed s i g n i f i c a n t l y over a period of a few weeks.  For t h i s reason, a check was made of the  c a l i b r a t i o n with a f r e s h l y prepared standard solution before each group of samples was analysed, and i f a s i g n i f i c a n t change-had occurred, a new c a l i b r a t i o n was prepared.  The results from a t y p i c a l c a l i b r a t i o n are given i n Table IV-1  and •shown p l o t t e d i n Figures IV-1 and IV-2. An estimate of the accuracy of the chromatographic given i n Table IV-2.  analysis i s  The r e s u l t s of the • i n d i v i d u a l peak height measurements  are given f o r two solutions, solutions lhA, f o r -which the v a r i a t i o n i n i n d i v i d u a l peak height measurements was larger than with any other standard solutioniased, and solution hA f o r which the v a r i a t i o n i n i n d i v i d u a l measurements was larger than with any other standard solution i n the kO to 60 percent composition range.  I t can be seen from t h i s table that f o r d i l u t e solutions,  no s i g n i f i c a n t error was introduced by the analysis when the concentration was expressed to the nearest 0.1 mole percent, and that f o r concentrated solutions a maximum error of +0.1 mole percent was introduced by the analysis when the concentration was expressed to the nearest 0.1 percent.  (The actual error was  probably less than +0.1 mole percent f o r concentrated solutions, as at least two samples of every mixture to be analysed were used with the chromatograph and the r e s u l t s obtained averaged.)  Toluene-methanol Mixtures Toluene-methanol mixtures obtained during the phase equilibrium studies were analysed using a Bausch and Lomb "Abbe-3L" refractometer. The temperature  of the refractometer prisms was c o n t r o l l e d with water c i r c u l a t e d  from a Colora Messtechneck Co. Ltd. "Ultra-thermostat". v a r i a t i o n of the water i n the thermostat was  +0.02°  The range of temperature  C.  The refractometer was c a l i b r a t e d with standard solutions prepared i n  TABLE IV-1  IV-3  CHROMATOGRAPH CALIBRATION FOR BENZENE-TOLUENE SYSTEM tfole Percent Benzene  Log Benzene-toluene Mole Ratio  2.7k  -1.5502  4.16  10.33 21-33 3h.lk 41.07  56.55  57-80  58.51  Log Toluene-benzene Mole Ratio  -I.O836 -.6694  •1567  .3094  .1492  -.1492  •3369  -.1366  -.3032 -•3353 -.3369  97-02  -.91U0 -1-5133  98.14  •0637  -.1145  66.73 68.40 68.47  75.01 82.7^ 89.13  -•3110 -.0520  .1145  .1366  Toluene-benzene Peak Height Log Ratio  -r..2644  -I.3629  -.9385 -.5569 -.2853 -.1567  Log Benzene-toluene Peak Height Ratio  -.4774 -.6807  -1.7246  •3261 .4740  -.O636  -•3094 -•3261  -•3369  -.4740 -•5042  -.5060  -•6315 -•8179 -1.0374 -I.6189 -I.8265  TABLE IV-2  IV-4  I ACCURACY OF CALIBRATION OF CHROMATOGRAPH Mixture No.  Mole Percent Benzene  14A i ii iii  97-02 97-02 97.02  kA i  57-80 57-80 57-80 57-80  ii iii iv  Height ' Height Benzene Toluene Peak Peak  ?oluene -benzene eak Height Ratio  Mole Percent Benzene from C a l i b r a t i o n Curve  221.5 i n . 5-3^ in. 222-5 i n . 5-37 i n 220.5 i n . 5-27 i n  .0241 .0239 • 0239  97-02 97-04 97-04  134.4in. 63.2 i n I36.6 i n . 6k.5 i n I37.8 i n .65.O i n 139-2 i n . 65.9 i n  .470 .472 .472 •473  57-9 57-8 57-8 57-7  3  IV-5  -1.8  -1.6  -1.4  -1.2  -1.0 LOG  -0.8 -0.6 Toluana moles Benzene  m n l t t a  F i g u r e IV-1  -0.4  -0.2  0  0.2  iv-6  -1.8  -1.6  -1.4  -1.2 LOG  -1.0  -0JB  -0.6  mglw Benzene moles Toluene Figure IV-2  -0.4  -0.2  0  0.2  IV-7  the same manner as was used f o r the benzene-toluene c a l i b r a t i o n described above. The refractometer prisms were cleaned before each set of readings with benzene and petroleum ether and between each reading with petroleum ether.  A period  of several minutes was allowed after the cleaning before the refractometer was used. ometer.  A hypodermic syringe was used to introduce samples to the r e f r a c t The f i r s t part of the contents of the syringe was rejected and then  just enough material added to the refractometer to f i l l the space between the two prisms.  Two  independent determinations were made f o r each mixture,  and  i f 'these determinations d i f f e r e d by more than one figure i n the fourth decimal place, the readings were rejected. For some unknown reason the c a l i b r a t i o n of the refractometer did not r  remain constant, but changed by three or four u n i t s i n the fourth decimal place p e r i o d i c a l l y .  For t h i s reason, i t was checked with pure toluene and  pure methanol before each set of readings was made, and i f a change had occurred i n the r e f r a c t i v e index of'these substances, the c a l i b r a t i o n redetermined.  was  The r e s u l t s of a t y p i c a l c a l i b r a t i o n are given i n Table  and shown p l o t t e d i n Figure  IV-3  IV-3.  The refractometer could be read to 0 . 0 0 0 1 units and the readings f o r a given substance were reproducible to + 0 . 0 0 0 1 units. which were almost pure toluene could be determined,  Composition  of mixtures  therefore, to ,+0.2 mole  percent, and of mixtures which were almost pure methanol to + 0 . 0 5 mole percent. Two  independent determinations of r e f r a c t i v e index were made on  each unknown sample to be analysed (except f o r a very few vapor samples where i n s u f f i c i e n t material was obtained f o r more than one determination). obtained were averaged and the average value used with r e f r a c t i v e c a l i b r a t i o n curves to obtain the sample concentration.  The values  index  TABLE IV-3  IV-8  TYPICAL REFRACTOMETER CALIBRATION FOR METHANOL-TOLUENE SYSTEM AT 20° C.  Mole Percent Methanol 100 95-79 90.69 87.52 80.56 74.46 69.76 60.86 53-19 42.02 35-75 31-81 24.61 24.49 15-90 6-73 0  Refractive Index 1-3272 1.3445 1.3627 1.3728 1-3923 1.4068 1.4168 1.4329 1.4446 1.4594 1.4663 1.4705 1.4772 l.4774 1-4847 1.4916 l .'4960  APPENDIX V  V-1  PURIFICATION OF MERCURY  Technical-grade mercury was p u r i f i e d f o r use i n the experimental 78 apparatus using procedures recommended by Sanderson  and the Handbook of  79 Chemistry and Physics  .  Surface•impurities were removed from the mercury  by f i l t e r i n g , i t through a chamois leather sealed funnel, and the clean metal was then air-bubbled for. 2k hours.  The surface of the mercury was  kept covered with a frequently changed 1 percent solution of n i t r i c acid during the bubbling i n order to a i d i n the removal of impurities such as dissolved a l k a l i metals, zinc, copper,.or lead.  The mercury,was next  washed three times i n a 110-cm. high, 10 percent sodium hydroxide scrubber, three times i n a similar 10 percent n i t r i c acid scrubber, and f i n a l l y three times i n a d i s t i l l e d water scrubber.  The mercury was introduced to each  scrubber i n the form of very fine droplets obtained by forcing i t through a section of chamois leather.  Mercury from the f i n a l water wash  was dried with clean b l o t t i n g paper and then vacuum d i s t i l l e d to remove traces of the noble metals or t i n .  TABLE 10  VI-1  VAPOR-LIQUID EQUILIBRIUM DATA FOR THE METHANOL-TOLUENE SYSTEM AT A PRESSURE OF ONE ATMOSPHERE (BENEDICT ET AL 5^)  Temp. °C.  100.61 70.25 66.44 65.58 64.47 64.10 63-79 63-67 63.58 63.62 63.95 64.51  Mole Liquid 0.0 13-0 26.6 40.7 59-3 69.2 77-9 84.3 88.2 92.7 96.9 100.0  Methanol Vapor 0.0 74.2 78.2 8O.3 8I.9 82.9 84.5 86.9 88.3 91.1 95-0 100.0  TABLE 11  VI-2  VAPOR-LIQUID EQUILIBRIUM DATA FOR THE METHANOL-TOLUENE  Pressure - mm. of mercury Run Number  -  35-125 36-125 37-125 38-125 39-125 40-125 17-125 42-125 18-125A 18-125B 43-125 23-125A 23-125B 22-125 27-125 41-125A" 41-125B 21-125B 41-125C 41-125D  SYSTEM AT 125°  C  Composition - mole percent methanol  Pressure  Liquid Composition  Vapor Composition  5530 5550 5575 5585 5585 5575 5520 5510 5420 5320 5320 5105 5030 4040 4440 3735 3710 3040 2730 2270 1625 1130  100 99-1  100 98.8 96.9 94.9  97-h  95-3 93-3 90.2 83-6 82.9 74.7 67.8 67.8 53-7 49.5 41.7 29-0 16.8 16.2 9-9 8.2 ^•9 2.0 0  91-5 88.6 88.6 86.2 84.8 84.7 82.4 81.9 80.2 ' 11-1  71.6 71.2 63-7 58.9 50.7 30.4 0  Equilibrium Ratio Methanol  1.00 •997 •995 •996 1.00 1.01 1.06 1.07 1.15 1-25 1.25 1-53 1.66 1.92 2.68 4.26 4.40 6.43 7.18 10.4 15-2  —_  Equilibrium Ratio Toluene  — 1-33 1-19 1.09 .985 .867 .695 .666 .545 .472 .475 .380 .358 • 3^0 • 31^ •3^1 •343 .403 .448 .518 .710 1.00  TABLE 12  VI-3  VAPOR-LIQUID E Q U I L I B R I U M .DATA FOR THE METHANOL-TOLUENE SYSTEM AT 150°.c.  Pressure - mm. Run Number  35-150 31-150 25-150 36-150 37-150 24-150 38-I5O  16-150B 16-150A 39-150 40-150 17-150 42-150 18-150 28-150 43-150  23-150A 23-150B 23-150C 22-150 27-150  41-150A 41-150B  Composition - mole f r a c t i o n Methanol  Pressure  Liquid Composition  Vapor Composition  10465 10520 10480 10530 10530 10500 10520 10500 10400 10450 10450 10290 10260 10090 9770 9400 9260 9080 8640 8590 766O 6155 6035 4845  100 99-1 99-1 97-7  100 99-0 99-0 97-5 97-2 95-4 95-4 94.0 92.4 92.4 92.4 89-3 88.5 87.1 84.9 82.7 82.1 80.1 79-3 79-3 75-1 67-6 66.6 57-7 52:4 42.2 23'.6 15.1 0  21-150  41-150C 41-150D 34-150B  of Mercury  3595 2720 2450 2065  91-h  95-3 95-2 93-2 90.5 90.3 90.1 83-5 82.6 74.7 66.8 55-6 52.6 48.9 4i.o 40.5 28.1 16.5 15-3 9-1 7-7 k.l  1.8  1.0 0  Equilibrium Ratio Methanol 1.00 •999 -.999 .998 .998 1.00 1.00 1.01 1.02 1.02 1.03 1.07 1.07 1-17 1.27 1.49 I.56 1.64 1-93 1.96 2.67 4.10 4-35 6.29 6.81 8.98 13.I 15-1 — —  Equilibrium Ratio Toluene  1.11 1.11 1.09 1.08 •979 .958 .882 .800 •783 .768 .648 .661 .510 .455 •390 •378 •389 •357 • 3^8 • 346 • 388 •394 .465 .516 .607 •778 .858 1.00  TABLE 13  Vl-4  VAPOR-LIQUID EQUILIBRIUM DATA FOR THE METHANOL-TOLUENE SYSTEM AT 175° C Pressure --•mm.'of Mercury Run Number  35-175 25-175 24-175 16-175B 16.175A 40-175 17-175 42-175 18-175 28-175 ^3-175 23-175 22-175 27-175 21-175 41-175 34-175  Composition - mole"percent-Methanol  Pressure  Liquid-' Composition  Vapor Composition  Equilibrium Ratio Methanol  Equilibrium Ratio Toluene  I83OO  100 99-1 97-6 95-2 90.3 90.3 83-3 82.2 74.5 64.9 55-0 49-1 39-2 27-5 15.0 7-4 1-7 •1.0 0  100 99-0 97-7 95.8 92.7 92.7 89.6 89.2 86.9 84.2 .81.8 80.3 77-1 72.0 62.0 44.3 17.2 H-3 0  1.00 •999 1.00 1.01 1.03 . 1.03 1.08 1.09 1.17 1-30 1.49  1.11 .958 • .875 •753 •753 .623 .607 . 514 .450  I836O 183OO 18280 18080 18080 17720 17660 17170 16470 15610 15120 13970 .I2O5O 9250  6495  ' 4290 3985 3525  1.64  1.97 2.62 4.13 5-99 10.1 11.3  —  .404  •387 •376 .386 .447 .602  • 843  .896 1.00  TABLE 14  VI-5  VAPOR-LIQUID EQUILIBRIUM .DATA FOR THE METHANOL-TOLUENE SYSTEM AT 200° C. Pressure- - -mm. of mercury Run Number  35-200 25-200 24-200 16-200A 16-200B  17-200 42-200 18-200 28-200 43-200 23-200 22-200 27-200 21-200 41-200 34-200  Composition - mole percent Methanol  Pressure  Liquid Composition  30220 30250 30140 30010 '29550 29530 28460 27480 25610 24280 22770 20730 17440 13150 9350 6515 6195 5650  100 99-1 97-6 95-1 90.0 90.0 81.4 74.2 61.7 54.0 46.7  37-9 26.3 15.1 6.8 •1-3 1.0 0  Vapor Composition  100 99-2 97-9 96.0 92.8 92.8 88.7 86.2 82.1 79-8 77-3 73-8 . 66.6 55-4 37-7 12.6 8.0 0  Equilibrium Ratio Methanol  1.00 1.00 1.00 1.01 1.03 1.03 1.09 1.16 1-33 1.48  1.66 1.95 2-53 3-67 5-54 9-69 8.00  Equilibrium. Ratio Toluene  — .889 .875 .816 • 720 ".720 .608 •535 .467 .439 .426 .422  •453 •525 .668 .885 •929 1.00  TABLE 15  VI-6  VAPOR-LIQUID EQUILIBRIUM RATIO FOR,THE METHANOL-TOLUENE SYSTEM'AT 225° C. Pressure r- mm. of Mercury Run Number  35-225 25-225 24-225 16-225A 16-225B 17-225 42-225A 42-225C 18-225 28-225 43-225 23-225 22-225 27-225 21-225 41-225 34-225  Composition - .mole percent Methanol  Pressure  Liquid Composition  Vapor Composition  47540 47390 47290 4683O 4567O 4567O 43290 41450 38390  100 99-1 97-5 95-1 89.5 89.2 80.0 73-8 63-3 56.6 52.9 45.2 36.3 25-7 14.6 6.2 1-3 .8 0  100 99-2 97-8 95-9 92.1 91.9 86.9 84.2 ,80.1 77-6 76.2 73-0 68.7 60.7 48.2 30.4 9-1 5.8 0  3638O  35150 32320 28790 23810 17730 12980 9570 9260 8600  Equilibrium Ratio Methanol 1.00 1.00 1.00 1.01 1.03 1.02 1.09 1.14 1.27 1-37 1.44 1.62 I.89 2.36 3-30 4.90 7.00 7-25  —  Equilibrium Ratio Toluene _ _  .889 .880 .837 •752 .750 •655 .603 • 542 .516 .505 .492 .491 •529 .606 • 7^2 • 921 •950 1.00  TABLE 16  VI-7  VAPOR-LIQUID EQUILIBRIUM RATIO FOR THE METHANOL-TOLUENE SYSTEM AT 250° rj.  Pressure - mm. of mercury  Composition - mole-percent  Run Number  Pressure  Liquid Composition  Vapor Composition  42-250B 42-250D 44-250B 44-250C 28-250A 43-250 28-250B 23-250 22-250 27-250 21-250 41-250 34-250 30-250  57680 55^50 54550 52980 4765O 43040 41840 37820 31200 23370 175TO 13700 13310 12600  71.8 67-0 65-3 62.1 52.1 44.0 42.1 35-4 24.9 14.2 6.0 1.1 .6 0  •75-7 74.8 74.2 73-2 69.7 66.1 65.1 61.5 55-6 40.6 24-2 C6 1.1 4.2 0  Equilibrium Ratio Methanol 1.05 1.12 1.14 1.18 1.34 1.50 1.55 -1.74 2.23 2.86 4.03 5-55 7.00 — —  methanol Equilibrium Ratio Toluene :862 .764 .744 .707 •633 .605 .603 .596 .591 " .692 .806 .949 .964 1.000  VI-8 TABLE 18 ACTIVITY COEFFICIENTS FOR METHANOL AT 125° C Columns are numbered to correspond with method of c a l c u l a t i o n discussed i n test.  Mole percent Methanol in Liquid 100 99-1 97-4 95-3 93-3 90.2 83.6 82.9 74.7 67.8 67.8 55-9 53-7 49-5 41.7 29.0 16.8 16.2 9-9 8.2  4-9 2.0  Calculation Method 1  2A  2B  1.000 1.001 1.003 1.006 1.011 1.023 1.058 1.065 1-13 1.20 1.20 I.38 1.42 1.51 1.68 2.15  1.000 1.001 1.003 1.005 1.010 1.022 1.059 1.066  1.000 1.000 1.002 1.004 1.009 1.021 1.058 1.060  1.000 1.000 1.000 1.002 1.008 1.020 1-053 1.060  1U3.  1.13'  1-13H19 1.19  2.88  2-95 3-54 3-55 4.25 4.47  1.21 1.21 1-39 1-43 1-52 1.70 2.19 2-97 3-04 3-63 3.71 4.47 4.76  1.21 1.21 1-39 1-43 1-53 1.72 2.22 3-02 3.10 3.78 3-82  4.66 4.96  3  1-37 l.4l 1.50 1.69 2.16 2.91 2.98 3.61 3-63 4^35 4.63  4  5  1.000 1.000 1.002 1.005 1.010 1.022 1.059 1.066 1-13 1.21 1.21 1.39 1-43 1-52 1.70 2.19 2.96 3.03 3-67 3.70  1.000 1.000 1-003 1.006 1.012 1.025 1-063 1.071 1.14 1.22 1.22  4.46  4.74  1.40 1.44  1.54 1-73 • 2.24 3-06 3-14  3-84 3-88  4.72 5.07  '  TABLE 19  Vl-9  ACTIVITY COEFFICIENTS FOR TOLUENE AT 125° C  Columns are numbered to correspond with methods of c a l c u l a t i o n discussed i n text. Ylole'percent Methanol in Liquid  1  Calculation Method 1  2A  2B  3  6-55 5-88  5.38 4.83 4.40 4.00 3-52 2.79 2.68 2.16 1.85 1.86 1.49  5.26 4.72 4.30 3.90  6.24 5.58 5.08 4.61 4.05 3-20 3.06  99-1 97-4 95-3 93-3 90v2 83.6 82.9 74.7 67.8 67.8  ,5.36 4.87 4.28 3-40 3-25 . 2.62 2.22 2.24  55-9  1-77  53-7 49-5 41-7 29.0 16.8 16.2  9-9 8.2  4-9 2.0 0  1.72 1.60  1.46 1.23 1-13 1.13 1.08 1.08 -1.04 1.023 1.000  1.44 1-34 1.24 1.066 1.006 1.008 ?997 1.007 .991 1.000 1.000  3-^3  2-73 2.62 2.12 1.81 1.82  -1.46 1.41 1.32 1.21 1.049  •99^ •995 .988 1.001 .986 •999 1.000  2.46  2.09 2.11 1.67 1.62 1.51 1.38 1.18 1.086 1.089 1.062 1.056 1.009 1.012 1.000  4 5-67 5.08 4.62 4.19 3-68 2.92 2.80 2.25 1.92 1-93 1-5^ 1.49 1.39 1.28 1.10 l . 028 1.029 1.011 1.020 •999 1.002 1.000  5 , 5-99 5-36 4.87 4.40 3-86 3-05 2.92 2.3^ 1.99 2.01 1.59 1.54  1.44 1.31 1-13 1.047  -1.047 1.024 1.030 I.005 1.005 1.000  TABLE 20  VI-10  ACTIVITY COEFFICIENTS FOR METHANOL AT 150° C  Columns are numbered to correspond with methods of c a l c u l a t i o n described i n text. Mole Percent Methanol in Liquid 100 099H 99-1 97-7 97-4 95-3 95-2 93-2 90.5 90.3 90.1 83.5 82.6 74.7 ,--66.8 55-6 52.6 48.9 4i.o 40.5 28.1 16.5 15-3 9-1 7-7 4.7 1.8 1.0  Calculation Method 1 1.000 1.004 .999 •998 1-003 1.001 1.002 1.009 1.011 1.018 1.021 1-049 1.046 1.12 1.18 1-33 1.38  1.42  1-59 1.60 •1-95 2.40 2.50 2-93 2.82 3-07  3-40 3-52  2A 1.000  1.004  •999 .998 1-003 1.002 1.003 1.010 1.014 1.020 1.022 •1.053 1.050 1-13 1-19 1-35 1.40 1-45  1.64 1.65 2.03 2-55 2.67 3.17 3.07 3-39 3-79 3-95  2B 1.000 1.003 •999 •996 1.002 1.001 1.002 .1009 1.014 1.020 1.022 1.054 1.052 1-13 1.20 1.36 1.41  1.46  1.66 1.67 2.07 2.63 2-75 3-29 3-20 3-55 3-99 4.16  3 1.000 1.000 -1. .999 •996 •999 •998 •999 1.006 1.004 1.010 1.013 1.038 1.039 1.11 1.17 1.32 1-37 l.4l l.6l 1.61 1.97 2.45 2.58 3-04 2.95 3-25 3.61  3-84  4  1.004 1.000 1.003 1-003 1.004 1.007 1.012 1.016 1.022 1.025 1.051 1.049 1.13 1.20 1.36 i.4i 1.45  1.64 1.65 2.03 2-55 2.66 3-16 3-07 3.38 3-78 3-94  5 1.000 1.004 1.001 1.004 1.004 1.007 1.009' -1.015 •1.021 1.027 1.029 1.063 1.063  1.14  1.22 1-38 1-43 -1.48 1.68 1.70 2.11 2.69 2.8l 3-38 3-30 3-67 4.15 4-33  TABLE 21  VI-11  ACTIVITY COEFFICIENTS FOR TOLUENE AT 150° C  Columns are numbered to correspond with methods of c a l c u l a t i o n described i n text. Mole Percent Methanol, i n Liquid 99-1 99-1 97-7 97-4 95.3 95-2 93.2 ' 90.5 90.3 90.1 83.5 82.6 7U.7 66.8 55-6 52.6 1+8.9 4i.o 1+0.5 28.1 16.5 15-3 9-1 7.7 4-7 1.8 1.0 0  Calculation Method 1  5.68 5.65  , 2A  4.03 4.06 5-53 3-97 5.50 3-90 U.98 3-57 3-50 -U.87 3-22 4.49 4.03 2.91 2.86 3-97 3-89 2.79 3-24 2.34 3.28 • • 2.38 2.49 1.82 2.15 1-59 1.77 1-33 1.28 1.69 1.30 1.72 1.47 1.13 1.12 1-45 I.030 1.29 1.16 .985 .987 1-15 1.002 • •;98i 1.085 •993 1.056 •994 1.025 1.000 1.017 1.002 1.000 1.000  2B  3  4  3-95 3-92 .3-84 3-83 3-45 3-38 3-11 2.82 2.76 2.71 2.27 2.31 1.77 1-55 •1.30 1-25 1.27 l.ll 1.099 1.016 •977 • 978 •975 .989 •993 •998 1.002 1.000  5-20 5.18 5-06 5.02 4.54 4.45 4.09 3-66 3-60 3-53 2.92 2-97 2.25 1.95 1.61 1.54 1.56 1-35 1-33 1.19 1.094 1.095 1.050 1.054 1-035 1.015 1-025 1.000  4-43 4.42 4.32 4.28 3-87 3.80 3-49 3-13 3-08 3-02 2-59 . 2.67 1.94 I.69 l.4i 1-35 1.37 1.19 1.18 1.076 1.015 1.015 •998 1.008 1.004 1.002 1.004 1.000  5 4.81 4.79 4.69 4.64 4.18 4.10 3.76 3-37 3.31 3-24 2.69 2-73 2.07 1.80 1.49 1.42 1.44 1-25 1.23 1.12 1.041 1.040 1.014 1.021 1.013 1.006 1.006 1.000  TABLE 22  VI-12  ACTIVITY COEFFICIENTS FOR METHANOL AT 175° C. Columns are numbered to correspond with methods of c a l c u l a t i o n described i n text. Mole Percent Methanol i n Liquid 100  99-1  97-6 95-2  90.3 90.3  83-3  82.2  74.5  64.9 55.O 49.I  39-2  27-5  15.0  7-4  1-7 1.0  Calculation Method  1  1 1.000 1.002 1.001 1.006 1.015 1.015 1.040  1.047 1.093 1.17 1.28  1-35 1.50 1.72 2.09 2.13  2-37 2.46  2B 1.000 1.001 1.001 1.006 1.019 1.019 1.052 •1.059 1.12 1.21 1-34 1.43 1.62 1.92 2.44  2-59 2-99 3-12  3  4  5  1.000  1.000  •997 •999  •999 •999  1.000 1.002 1-003 llOlO 1.025 1.025 I.O63 1.070 1-13 1.22 1-36  •1.002 1.006 1.006 1.027 -1.032 1.080 1.18 1.28  1-35  1.003 1.015 1.015 • 1.047 1.054 1.108 1.19 1-32  1.40  1.51  I.58 1.86  2.19 2.28 2.61 2.70  2-33  1-77  2.44 2.81 2.92  1.46 1.65  1-97 2.51 2.70 3-15 3-29  TABLE 23  Vl-13  ACTIVITY COEFFICIENTS FOR TOLUENE AT 175° C Columns are numbered to correspond with methods of c a l c u l a t i o n described i n text. Mole Percent Methanol i n Liquid  99-1 97-6  95-2 90.3 90.3 83-3 • 82.2  74.5 64.9  55-0  49.I  -39-2 27.5 15-0 7-^ 1-7 1.0 0  Calculation Method  1  2B  3  4  5  5.78 .4:98 4.54 3.86 3.86 3.13 3.04 2.50 2.10 1.80 1.66 1.49 1.32 1.17 1.11 • 1.025 1.013 1.000  3.23 2-79 2.56 2.19 2.19 1.80 1-75  5-04 ^•33 3-9U 3-33 3-33 2.68 2.60  4.42  1.28 1-13 1.069 1.009 •965 .956 •999 .998 •997 1.000  1.82 1.56 1-^5 1-31 1.20 1.098 1.070 1.016 1.002 1.000  •3-91 3-56 3.05 2-59 2.59 2.10 2.05 1.70 1.45 1.27 1.19  1.48  2.14  l.ll  1.033 •99^ 1.015 1.001 •999 1.000  3.78 3-^3 2.90 2.90 2.34 2.28 1.88 1.59 1.38 1.29 . 1.18 ,1.088 1.027 1.032 1.006 1.002 1.000  TABLE 24  VI-14  NATURAL LOGARITHM OF THE,RATIO -OF THE' ACTIVITY COEFFICIENTS FOR METHANOL AND TOLUENE' AT'125° C Columns are numbered-to correspond with methods-of c a l c u l a t i o n described i n text. Mole Percent Methanol i n Liquid 99-1 97-k 95-3 93-3 90.2 83-6 .82.9 74.7 67.8 67.8 55-9  •53-7  L9.5 - 41.7 29.0 16.8 16.2 9-9 8.2 k.9 2.0  •  Calculation Method l  2A  2B  -1.879 -1.769 -1.674 -1-572 -1.431 -1.166 -1.116 -.839 -.614 -.621 -.254 -•193 -.055 .146 .556 •937 .961 -I.183 1.187 1.451 1.476  -1.682 -1-573 -1.479 -1-375 -1.236 -.970 -.921 -.647 -.425 -•433 -.069 -.010 .123 • 322 • 720 ,1.081 1.104 .1.307 - 1-304 1.508 1.561  -II66O -1.550 -1.455 -1.352 -1.212 , -.948 -.898 -.623 -.401 -.408 < • -.045 .016 .148 •348 .748 1.112 1-135 1-342 1-340 •1.548 1.603  3 -I.828 -1.719 -1.623 -1.519 -I.378 -1.112 -1.06l -.784 -.56I' -•569 -.200 -.139 -.007 .200 .604 .988 1.008 1.223 1-235 1.243 ..1.520  4 -1-735 -1.623 -1.526 -1.423 -1.281 -1.015 -.965 --.687 -.463 -.471 -.106 -.046 .087 .288 .690 1.057 ,1.081 1.290 1.288 1.497 1-5,54  5 -1.790 -I.676 -l."576 -1.470 -1-325 -1.053 -1.QO3 -.720 -.492 -499 -.129 -.067 . .068 - 275' .687 ,1.072 1-097 I.322 1.328 1-547 1.619  TABLE 25  vi-15  NATURAL LOGARITHM; OF THE RATIO OF THE ACTIVITY COEFFICIENTS FOR METHANOL AND TOLUENE AT 150° C. Columns are numbered to correspond with methods o f . c a l c u l a t i o n described i n text. Mole Percent Methanol i n Liquid  1  99-1 99-1 97-7 " 97-4 95-3 95-2 93-2 90.5 90.3 90.1 83.5 82.6 74.7 66.8 55-6 52.6 48.9 • 41.0 1+0.5 28.1 I6.5 15-3 9.1 ' 7-7 4.7 1.8 1.0  Calculation Method l  2A  2B  -1-733 -1-733 -1.712 -I.702 -1.604 -I.582 -1.493 -1.383 -1-359 -1-337 -1.126 -1.143 -•799 -.599 -.287 -.207 -.190 .080 .102 .1+17 •731 •775 .986 •954 1.069 1.198 1.242  -1-399 -1.401 -1.381 -1.360 -1.271 -1.249 -1.160 -1.054 -1.029 -1.006 -•779 -.818 -.476 -.281+ .018 •093 .106 .367 •359 .680 •953 •994 •1.174 1.129 1.225 1-333 1-371  -1-370 -I.367 -1.346 -1-340 -1.234 -1.216 -1.127 -1.-22 --997 -•975 -.768 -.786 -.446 -.254 .050 .126 •139 •399 .419 .712 •992 1.033 1.218 1-175 1.274 1-385 1.424  3 -1.649 -1.649 -1.626 -1.615 -1.516 -1.494 -1.403 • -1.294 -1.270 -1.245 -1-036 -1.050 -.708 -.508 -.196 -.118 -.099 •171 .191 .502 .810 •855 1.062 1.029 1.143 I.269 1-320  4 -1.484 -1.485 -1.461 -1.451 -1.350 -1.328 -1.237 -1.126 -1.102 -1.079 -.903 -.933 -.541 -•344 -.038 •039 .056 •317 •337 .636 •923 .965 1.154 1.113 1.215 1.329 1.368  5 -1.566 -1.566 -1.540 -1-530 -1.425 -1.403 -1-309 -1.194 -1.170 -1.148 -•927 -.942 -.594 >-389 -•073 .008 • 030 •299 •319 •637 • 950 •995 1.205 1-172 I.287 1.142 1.460  TABLE 26  VI-16  NATURAL LOGARITHM OF THE RATIO•OF THE ACTIVITY COEFFICIENTS FOR METHANOL AND TOLUENE AT 175° C Columns are numbered to correspond with methods of c a l c u l a t i o n described i n text. Mole Percent Methanol i n Liquid  99-1 97-6 95-2 90-3 90.3 83-3 82.2 7U.5 -64.9 55-0 49.1 39-2 27-5 15.O 7-4 1-7 1.0  Calculation Method  1 -1-753 -1-603 -1-507 -1-337 -1-337 -1.000 -1.066 -.827 -•589 -•345 -.202 .006 .267 •577 .651 •839 .888  • 2B -1-173 -1.024  -.928 -.763 -.763 -•538  -.504  -.279 -.060 .165 .289 .472 .688 .936 •953 1.098 1.141  3 -1.620 -1.467  -1.369 -I.196 -1.196 -•959 -•295 -.686 -.436 -.197 -.069 1138 •••395 •693 •758 -942  -990  4 -1-364 -1.212 -1-111 -•935 --935 -.698 -.663 -.428 -.198 .035 .165 •358 •587 .850 •879 1.030 1.074  5  -1.483 -1-327 -1.222 -1-038 -1.038 -.790 -•754 -.509 -.264 -.017 .122 •335 •592 .895 .961 1.142 1.190  Vl-17  TABLE 27 NATURAL LOGARITHM, OF THE RATIO OF THE ACTIVITY COEFFICIENTS FOR METHANOL AND TOLUENE CALCULATED BY THE METHOD OF BLACK FOR TEMPERATURES OF 200° AND 225° C  200° C Mole Percent Methanol i n Liquid 99-1  97-6  95-1 90.0 90.0 '8l.4 74.2  61.7 54.0 46.7 37-9  26.3  15.1  6.8 1-3 1.0  225° Logarithm Ratio  -I.I36 -1.111 -1.024 -.861 -.861 -.619 -.421 — 145 .022 .164  .330  •512 •715 .868 1.134 .894  Mole Percent Methanol i n Liquid 99.1 97-5 95-1  89-5  89.2 80.0 73-8 63.3  •56.6 52.9 45-2  36.3 25.7  14.6 6.2  1-3 0.8  Logarithm Ratio  -.963 -.941 -873 -•725 -.719  -.511 -.376 -.165 -.038 .029 •159 .306 .432 .482 •765  .888 •893  TABLE 30  Vl-18  COMPARISON OF ACTIVITY COEFFICIENTS CALCULATED FROM EQUATION OF BLACK AND FROM REDLICH AND KISTER CORRELATION FOR METHANOL, AND TOLUENE--AT 125° C  Methanol Mole Percent Methanol i n Liquid  99-1  97-4 95-3 93-3 90.2  83.6 82.9 74.7 67.8 67.8  55-9 53-7 49.5 41.7  29-0 16.8 • 16.2  9-9 8.2  4.9 2.0  Toluene  Black's Equation  Correlation  ^Difference  Black's Equation  1.000  1.000 1.002 1.006 1.012  0 .1 •"0 0 .1 0  5-99  1.003 1.006 1.012 1.025 I.O63 1.071  ,1.14 1.22 1.22  1.40  , 1.44 1-54  1-73 2.24 3-06  3-14  3-84 3.89 4.72 5.07  1.024 I.O63 1.068  1.14  1.22 -1.22 1.39  1.42  1.52 1-71 2.17 2.96 3-01 3-69 3-92 4.44  4.99  •3  0 0 0  •7 •7  1-3  112:  3-1 3-2  4.1  3.9 .8 6.0  1.6  5.36 4.87  4.40 3-86 3-05 2.92 2-35  1-99  2.01 , 1-59 1.54  1.44  I.32 1-13  1.047 1.047 I.023 1.030 1.005 I.005  Correlation 6.00 5.49 4.94 4.50 3-93 3-02  •3.00 2-35 -2.00 2.00 1.60  1.55  - 1.46 1-32 1.16 1-055 1.051 1.020 1.014 1.005 1.001  ^Difference .2  2.4 1.4 2.2  1.8 1.0  '2-7 .0  •5 .5 .6 .6  :ilk  0  2.6 .8  .4 •3  1.6 0  .4  vi-19  TABLE 31 COMPARISON OF ACTIVITY COEFFICIENTS CALCULATED FROM EQUATION OF BLACK AND FROM REDLICH AND KISTER CORRELATION FOR METHANOL AND TOLUENE AT 150° C  Methanol Mole Percent Methanol i n Black's Liquid Equation - "Correlation ;  IOO 99-1 99-1  97-7 97-4 95-3 95-2 93-2 90.5 90.3 90.1  83-5 82.6 , 7U.7 66.8 55-6 52.6 48. 9 41.0 40.5 28.1  16.5 15-3  9-1  7-7 k.l  1.8 1.0  1.004 1.001 1.004 1.004  1.000 1.000 1.001 1.002  1.007 1.009  1.005 1.005  1.015 1.021 1.027 1.029  1.011 1.020 1.021 1.022 I.O57 I.O63  I.O63 I.O63 1.14 1.22  1.38 1-43 1.48  1.68 1.70 2.11  2.69 2.81  3-38 3-30 3-67  4.15  4-33  Toluene ^Difference  •3  4.69  4.76  4.l8  4.27 4.25 3-91 3-52 3-k9  .2 .2 .4 .4 .1  .6 •7 .6  0  1.41 1.48  i:k\ 0  1.65  1:8  2.05 2.65  2.8  1.66 2.74  3-29  5.O8 5.O8  4.81  1.36  1.21  Correlation  .4 .1  •9 .8 l.U  1-13  Black's Equation  2.4  1-5 2-5  2-7  3-kk  3-82  4.2 4.0  4.26 4.40  2.6  1.6  4-79 4.64  4.10  3-76 3-37 3-31 3-24  2.69  2-73 2.07 1.80  1.49 1-43 1.44 1.25 1.23 1.12 1.041 1.040 1.014 1.021 1.013 1.006 1.006  4.69  3-46  2.76 2.69 2.17 1.82 1-51 I.45 I.38 1.26 1.26 1-13  1.047 1.042 1.016 1.011  1.004 1.001 1.000  ^Difference  5-3 5-7 1-5 1.1 2.2  3-5  4.0  4.4 5-U ' 6.8 2-5 " 1-5 4.8 l.l  1-3 1.4 4.2" .8 2.4 •9 .6 .2 .2 1.0  •9 •5 .6  TABLE 32  VI-20  COMPARISON OF ACTIVITY COEFFICIENTS CALCULATED FROM EQUATION OF BLACK AND FROM REDLICH AND KISTER CORRELATION FOR METHANOL AND TOLUENE AT 175° C  Mole Percent Methanol i n Liquid 99-197-6 95-2 90.3 90.3 83-3 82.2 74.5 64.9 55-0 49.1 39-2 27-5 15.0 7-4 1-7 1.0  Black's Equation 1.002 1.003 1.010 1.025 1.025 .1.063 1.070 1-13 1.22 1.36 1.46 1.65 1-97 2.51 2.70 3-15 3-29  Methanol Correlation  ^Difference  1.000 1.001 1.005 1.021 1.021 1.055 1.062 .1.12 1.21 1-32 1.41 1-59 1-91 2.45 2-95 3-44 3-51  .2 .2 •5 .4 .4 .8 .8 •9 .8 2.9 3-4 3-6 330 2.4 9-2 8.4 6.6  Black's Equation 4.42 3.78 3-43 2.90 2.90 2.34 2.28 1.88 1-59 I.38 1.29 1.18 1.088 1.027 1.032 1.006 1.001  Toluene .  Correlation  ^Difference  4.39 3-78 3-67 3-03 3-03 2.42 2.35 1.95 1.64 1.42 1-33 1.21 1.102 1.031 1.008 1.000 1.000  •7 8.2 6-5 4.4 4.4 3-4 3-1 3-6 3-0 2-9 3-1 2-5 1.4 .4 2.4 .6 .1  TABLE 33  VI-21  COMPARISON OF ACTIVITY COEFFICIENTS CALCULATED FROM EQUATION OF BLACK AND FROM REDLICH AND KISTER CORRELATION FOR METHANOL, AND TOLUENE AT 200° C.  Mole Percent Methanol i n Liquid  99-1 97-6 95-1  90.0 90.0 81.4 74.2  61.7  54.0  46.7  37-9  26.3 15-1  6.8 1-3  .1.0 0  Methanol Black's Equation  1.003  1.004 1.011 1.029 1.028  1.070 1.12 "  1.24 1-33 1.43  1.58 I.83 2.13 2.44  3-12 2.46  Correlation 1.000 1.001  1.005 1.020 • 1.020 1.06l 1.11 1.21  ^Difference  •3 •3 .6  •9 •9 .8 .8  2.4  1.28  3.8  1-37  4.2  ,2.21  3.8 3-8 14': 7  1.50 1.76  2.80 3-42 3-U6  5-1  9-6  40.7  Toluene Black's Equation Correlation 3.12 3.O5 2.82 2.43 2.43  1.99 1.71 1.43 1.30 1.22  1.14 1.094 1.043 1.022 1-003 1.007  3-71 3-48  3-14 2.62 2.62 2.06  1-77 1.47 1-35'. , 1.27 ' 1.19 1.101 1-038 1.009 1.000 1.000  ^.Difference  I8.9 14.0 11-3 7.8  7.8 3-5 3-5  2.8  3-8 4.1 4.4  .6  •5 1-3  •3 •7  VI-22  TABLE 3!+ COMPARISON OF-ACTIVITY COEFFICIENTS CALCULATED FROM EQUATION OF BLACK AND FROM REDLICH AND KISTER CORRELATION FOR METHANOL, AND. TOLUENE AT,225° C  Mole Percent Methanol i n Liquid  99-1 97-5  95-1 89.5 89.2 80.0 •73.8  63-3 56.6  52.9  45.2 36.3 25.7  14.6  6.2  1.3 0.8  Methanol Blackss Equation 1.001 1.005 1.010 1.028 1.030 1.071 .1.11 • 1.19 1.26 1.30  1.39  •1.52  1.68  1.90 2.21 2.45 2.46  Correlation 1.000 1.001  1.004  1.017 1.018 I.O58  1.094 1.17 •1.22 1.26 1.34 • 1.46 1.67 2.06 2.6l 3-12  3-19  Toluene 'Black's ^Difference Equation .1 .4  .6  2.62  ,2.57  2.42 2.12 2.11  •l.l l.l 1.2 1.4  •1.6l  1.7  i.4o  '3-1 3-1  3-6  4.0  .6 8.4  18.1  27-3 29.6  1-79  1.31  1.26 •1.19 1.12 1.093  1.048  :  I.028 1.006 I.009  Correlation  3-11  •2.95  2.73 • 2.33  2.31 I.87 • 1.67 1.45 1-35 1.30 1-23 1.16 I.090 1-035 •1.007 •1.000 1.000  ^Difference  I8.7 14.7 12-9 970  9-4 4'. 5 3-7 3-5 3-1 3-1  3-4 3-6 - ~^3 1-3 2.0  .6 •9  APPENDIX VII  VII-1  PROCEDURES USED TO PURIFY BENZENE, TOLUENE, AND METHANOL FOR VAPOR PRESSURE MEASUREMENTS  Benzene  Bender, Furukawa, and HjHLcbman  57  Three samples of benzene were used.  The f i r s t ,  reagent-grade  benzene, was treated with s u l f u r i c acid u n t i l i t gave a negative test f o r thiophene, then washed with water, and next dried over calcium chloride sodium wire.  I t was f i n a l l y d i s t i l l e d over fresh sodium wire.  and  The second  sample, P h i l l i p s Petroleum Company research-grade benzene, was c e r t i f i e d to be  99-93+.03 percent benzene.  The t h i r d sample, thiophene-free, reagent-  grade benzene, was dried over sodium wire and then d i s t i l l e d .  The three  samples gave consistent r e s u l t s . 58 Gornowski, Amick, and Hixson Baker's C P .  thiophene-free'benzene was agitated with concentrated  s u l f u r i c acid and then washed twice with d i s t i l l e d water. next treated twice with 0.1 with d i s t i l l e d water.  The sample was  normal sodium hydroxide and again washed twice  The benzene was f i n a l l y twice p u r i f i e d by f r a c t i o n a l  crystallization.  Young  5 9  Commercial benzene was f i r s t d i s t i l l e d , then twice f r a c t i o n a l l y c r y s t a l l i z e d , and next shaken repeatedly with concentrated s u l f u r i c acid.  The  f i n a l p u r i f i c a t i o n was by f r a c t i o n a l d i s t i l l a t i o n . \  3 Griswold, Andres, and Klein Thiophene-free benzene was p u r i f i e d by f r a c t i o n a l d i s t i l l a t i o n .  VII-2 2 v. Huhn The best grade of benzene commercially available at the time of the measurements was dried by d i s t i l l a t i o n and then stored over sodium wire u n t i l used.  Toluene 62 Krase and Goodman Toluene of an unstated grade was once d i s t i l l e d . 2 v. Huhn The best grade of toluene commercially available at the time o f the measurements was dried by d i s t i l l a t i o n and then stored over sodium wire u n t i l used. 63 Zmaczynski Toluene -supplied by the International Bureau of Physico-chemical Standards was used.  This material was considered to have been p u r i f i e d as  c a r e f u l l y as possible.  3 Griswold,  Andres, and K l e i n Nitration-grade toluene was p u r i f i e d by d i s t i l l a t i o n .  65  Methanol  Kay and Donham A high-purity commercial sample of methanol was d i s t i l l e d over sodium; 200 ml. of each 1500 ml. l o t were retained f o r the measurements.  VII-3 Young  Methanol was prepared by d i s t i l l i n g c r y s t a l l i n e methyl oxalate and ammonia.  The d i s t i l l a t e was r e d i s t i l l e d , then d i s t i l l e d over quioklime, and  f i n a l l y over barium oxide.  I t was then allowed to stand over anhydrous  calcium sulphate f o r a number of weeks, after which i t was d i s t i l l e d s i x times to a constant b o i l i n g point.  Rao, Sarma, Swami, and Rao  52  Methanol free from acetone was d i s t i l l e d before use.  200, AZEOTROPE  COMPOSITION  150  o o I  0>  100  0) Q.  E  K  50  O  This work  ©  Benedict et al  ©  Berg and Harrison  3  Robinson et al  (I  86  88  90 MOLE  3V Xi KJ A> ^  92 PERCENT  94  96  METHANOL  98  100  2.0d  0  1  I  I  10  20  30  I  i  40 50 M O L E PERCENT  I  I  60 70 METHANOL  I  I  80  90  100  -2.0d  0  I  10  I  20  1  30 MOLE  I  40  i  50  PERCENT  1  60  I  70  METHANOL  I  80  I  90  I  100  ' .teh%7 VZ  RATIO  O  10  20  30 MOLE  40  OF  50  PERCENT  ACTIVITY  60  70  COEFFICIENTS  80  90  100  METHANOL  I tea  _  ,  _  ;  -  -f  r  f  c  ^j  1.50  RATIO IN T H E  OF  ACTIVITY  SYSTEM AT  o c o  £ c  COEFFICIENTS  METHANOL-TOLUENE 200°  C.  Q> C  a>  3  -.50O  Experimental  —  Correlation  data and Black's  Equation  -1.50  -2.0CL 0  10  20  30 MOLE  40  50  PERCENT  60  70  80  90  100  METHANOL  fa, 2 8 '  MOLE  PERCENT  METHANOL  *  Mc  SL  4  I RATIO  Curves  i  i  COEFFICIENTS  SYSTEM-METHANOL-TOLUENE AT  -.50  I  OF ACTIVITY  N THE  1.00  I  125° C.  are numbered to  correspond with methods of calculation described in text  -1.00  -1.50  0  10  20  30 .MOLE  40  50  PERCENT  60 METHANOL  70 /£3<S|7  o c o ••— Q)  E  Q> C  o 3  C  30 MOLE  40  50  PERCENT  60  70  METHANOL  100  /,<c3> W L 4 V Z  i  I  1.50 —  .  I  I  I  RATIO OF A C T I V I T Y  IN  1.00  I  THE  SYSTEM AT  I  COEFFICIENTS  METHANOL - TOLUENE 175°  C.  .50  o c a  C  JZ a> a> o E  -.50 — O  Experimental data and Black's Method  ^~^Q  —  — Correlation  c _J  -1.00  -1.50  -2.001  i 10  i 20  i 30 MOLE  1  40  I  50  PERCENT  I  60  1  70  METHANOL  80  I  I  90  100 A<SZ61  I96X A/  NICHROME  DETECTING  WIRE  BRIDGE  /&3 6~7i  MERCURY RELAY  SPE EDOMAX  D. C. N U L L INDICATOR AND  RECORDER CONTROLLER  UO VOLT A.C. 6 VOLT D.C. RECTIFIER  (A)  AMPLIFIER MUELLER  L  BRIDGE  OFF - ON HEATER  IT  AUTOTRANSFORMER 110 V  3  LINE  STEADY- ON  110 V  SWITCH  HEATER  IA TEMPERATURE  CONTROL  CIRCUIT  AUXILLIARY HEATER  oo *t «M AP  8*  7  X.  )(6  l>c I  J>c§  5^<  3>C >C4  THERMOCOUPLE  J  3>C ) ( 4  IX  X )C2  POSITION  !  POSITION  A  POSITION  ±2.  FOR  TEMPERATURE  B  SURVEY  »1  S 12 TO  ACUUMl MERCURY CUT:-OFF VALVE  M  V  J  MERCURYSEALED GROUND GLASS JOINT  TO PRESSURE SAMPLING  \  TUBE  J  GLASS TO  METAL SEAL  LIQUID SAMPLE COLLECTION TUBE VAPOR  SAMPLE  COLLECTION TUBE  K SAMPLE  COLLECTION  TUBE MERCURY  7J1 -5"-^ 5^ ^  H  f  r  \  ^  |so  .fe o&  ^  ^  -^j  TRAP  

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0059061/manifest

Comment

Related Items