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The design and construction of an apparatus suitable for the measurement of the pressure-volume-temperature.. Gattenmeyer, John Leonard 1950

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It To fit CV/9 . ' THE DESIGN AND CONSTRUCTION OF AN APPARATUS SUITABLE FOR THE MEASUREMENT OF THE PRESSURE - VOLUME - TEMPERATURE RELATIONS OF GASES A Thesis submitted i n P a r t i a l Fulfilment of The Requirements for the Degree of MASTER OF APPLIED SCIENCE in CHEMICAL ENGINEERING JOHN LEONARD GATTENMEYER THE UNIVERSITY OF BRITISH COLUMBIA SEPTEMBER, 1950. T H E UNIVERSITY O F BRITISH C O L U M B I A V A N C O U V E R , C A N A D A D E P A R T M E N T O F C H E M I S T R Y October 2, 1950. To Whom It May Concern: This i s to c e r t i f y that the t h e s i s e n t i t l e d "The Design and Construction of an Apparatus Suitable f o r the Measurement of the Pressure-Volume-Temperature Rela tions of Gases" by Mr. John Leonard Gattenmeyer measures up to the required standards of the M a s t e r s th e s i s i n t h i s Department. Yours braiy, -ew ABSTRACT An apparatus designed a f t e r the f a s h i o n of Young and of Kay has been c o n s t r u c t e d and assembled f o r the determina t i o n of the pressure - volume - temperature r e l a t i o n s h i p s of pure compounds up to 200 atmosphere and JbO° C. Pressure measurement depends on the known charac t e r i s t i c s of pure n i t r o g e n , and a u x i l i a r y apparatus has been assembled f o r the p r o d u c t i o n and use of t h i s . Constant temperatures are o b t a i n e d by b o i l i n g under a constant p r e s s u r e the f o l l o w i n g compounds: carbon d i s u l f i d e , chlorobenzene, broraotaenzene, a n i l i n e , methyl s a l i c y l a t e , 1-broraonaphthalene, and mercury. These compounds have a l l been p u r i f i e d and have been used to c a l i b r a t e a thermocouple f o r use i n the apparatus. Normal-butanol has been c a r e f u l l y p u r i f i e d f o r i n s e r t i o n i n t o the. apparatus ahd d e t e r m i n a t i o n of i t s p r e s s u r e - volume - temperature r e l a t i o n s and i t s vapor-pressure. The t h e o r e t i c a l u t i l i z a t i o n of such data has been d i s c u s s e d . ACKNOWLEDGMENTS My sincere appreciation to Dr. Shemilt for his guidance in t h i s research, to the Shell O i l Company of Canada Limited for the Shell O i l Fellowship for 19 k 9 - 1 9 5 0 , and to the National Research Council for f i n a n c i a l assistance. I wish also to thank Mr. William Pye, Mr. Morris Simmons, and Mr. Arthur Werner f o r their valuable advice and material assistance. TABLE OF CONTENTS Page A. Introduction 1 B. Theoretical Discussion 3 ( 1 ) The Pressure - Volume - Temperature Relations of a Real G-as 3 ( 2 ) Vapor - Pressure Concepts 6 ( 3 ) The Extension of Thermodynamic Data. 2> C. Apparatus 1 1 ( 1 ) Types i n General Use 1 1 (a) The Constant Volume Apparatus 1 1 (b) The Constant Temperature Apparatus 1 1 ( 2 ) General Description of the Apparatus.. 1 1 ( 3 ) Construction and Operation of the Apparatus.... 1 2 (a) The Application and Measurement of Pressure » 1 2 (b) The Maintenance and Measurement of Temperature 14- (c) The Measurement of Volume 1 7 (d) Construction and Operation of the S t i r r i n g Device 1 7 D. P u r i f i c a t i o n of Materials..... 1 9 ( 1 ) The Generation and P u r i f i c a t i o n of Nitrogen.... 1 9 (a) Apparatus 1 9 (b) Procedure^. 2 1 ( 2 ) The P u r i f i c a t i o n of Mercury 2 2 ( 3 ) P u r i f i c a t i o n of Organic Compounds 2 3 (a) Apparatus 2 3 (b) Procedure. 2 1 ! TABLE OF CONTENTS (CONT.) Page D. P u r i f i c a t i o n of Materials (Cont.) 2b (!+-) The P u r i f i c a t i o n of Normal - Butanol.. 2b (a) Apparatus 27 (b) Procedure 28" E. Procedure and Results 3° (1) Calibration o f.the'Thick-Walled C a p i l l a r y Tubes 30 (2) Calibration of the Thermel. 33 (3) Loading the Ca p i l l a r y with an A i r Free Sample of Butanol... 33 (i|-) Loading the C a p i l l a r i e s with Pure Nitrogen.... 35 F. Summary and Recommendations..... 3° TABLE OF DIAGRAMS I. The Apparatus. I I . C i r c u i t Diagram of the E l e c t r o n i c Relay. I I I . The Generation and P u r i f i c a t i o n of Nitrogen. IV. C a p i l l a r y F i l l i n g Device. THE DESIGN AND CONSTRUCTION OF AN APPARATUS SUITABLE FOR THE MEASUREMENT OF THE  PRESSURE - VOLUME - TEMPERATURE RELATIONS OF GASES A. INTRODUCTION The volume occupied by a r e a l gas under a given tem perature and pressure has been the subject of investigation since the middle of the nineteenth century. The c a r e f u l studies of Regnault and of Amagat showed that r e a l gases do not obey the c l a s s i c a l equation PV a nRT, the combination of Boyle's and Charles* laws which suitably explains the beha viour of the hypothetical perfect gas. Since the time of Regnault, two general types of apparatus have been developed for the measurement of volumes at high pressures. One type, using a steel bomb to contain the gas, Is suitable f o r measuring pressure changes of tem perature at constant volume. The other type, and the one chosen for t h i s research because of i t s ease and f l e x i b i l i t y of operation, contains the gas sample i n a thick-walled c a p i l l a r y where isothermal pressure - volume changes can be v i s u a l l y observed. Work done i n t h i s f i e l d up to the present time has been l a r g e l y concentrated on the petroleum hydrocarbons. This has been almost necessitated because of the tremendous growth of that industry and the corresponding demand for thermodynamic data on petroleum products for equipment design purposes. The work of Sage and Lacey i n t h i s f i e l d has been p a r t i c u l a r l y outstanding. On the other hand, data on the oxygenated hydro carbons are meagre,! and as these compounds are becoming greater i n importance because of new synthetic processes, the deter mination of t h e i r thermodynamic properties Is desirable. As a consequence, the f i r s t step towards i n i t i a t i n g a program of research along t h i s l i n e , i s to assemble an apparatus suitable for such determinations. This thesis describes i n d e t a i l the design and cons tru c t i o n of apparatus for the determination of pressure - volume - temperature relationships up to 200 atmospheres and 3b0° C. and of vapor-pressures over the same range. In keeping with the programme of the study of the oxygen containing organic compounds, some progress has already been made i n preparing the apparatus for P-V-T determinations on normal-butyl alcohol. B. THEORETICAL DISCUSSION ( l ) The Pressure - Volume - Temperature Relations of a Real Gas. Ever since the studies of Regnault proved that r e a l gases do not ohey the simple gas law, e f f o r t s have been made to develop an universal equation to describe state behaviour. The best that can be done i s to represent the P-V-T data of a single compound with an equation the constants of which must be a r b i t r a r i l y determined. Further, the better the data are represented by d i f f e r e n t equations the more mathematically cumbersome and a r b i t r a r y do they become. One of the f i r s t t h e o r e t i c a l l y derived equations of state was that of Van der Waals. Its derivation Is based on two general concepts not applicable to the perfect gas. The f i r s t of these i s the f a c t that gas molecules occupy f i n i t e volume whereas no such condition i s stipulated for the perfect gas. The volume available f o r free movement accordingly i s not V the t o t a l volume, but V-b, where b i s representative of the volume of the molecules. The second concept recognizes the forces of a t t r a c  t i o n and repulsion between molecules which i s not applicable to the molecules of a perfect gas. Because the molecules on the boundaries of a vessel are attracted inwards by a force proportional to the square of the number of molecules present per unit volume, the r e a l pressure i n a gas exceeds the measured pressure P by a term a/V which i s proportional to the square of the density. The new volume and pressure factors when substituted in the perfect gas equation give, <P 4- a/V2) (v - b) 3 RT The Van der Waals equation has been found more accurate than the simple gas equation, but nevertheless devia tions of large magnitude occur f o r most gases to which the equation has been f i t t e d . Two other equations, both similar to the Van der Waals equation In t h e i r general form and i n the number of constants they contain, are the D i e t e r l c i ( 2 l ) . v RT ~ K§V and the Berthelot, P „ RT _ a V - b W H Although the D i e t e r i c i i s somewhat arb i t r a r y , the Berthelot recognizes the v a r i a t i o n of intermolecular forces with temperature with the term a/TV^. Although either equation may represent given data better than does the Van der Waals, i t cannot be said that they are better than the Van der Waals, The three equations so f a r mentioned are of further t h e o r e t i c a l interest because they can be put i n what i s known as the reduced form. Such a reduced equation contains no a r b i t r a r y constants, but instead three constants c h a r a c t e r i s t i c of a given substance, namely the c r i t i c a l volume, temperature and pressure. The a r b i t r a r y constants "a" and "b" may be found i n the terras of the c r i t i c a l constants from the following i d e n t i t i e s , OP) (g\T) T - 0 (DV2) T = 0 which hold at the c r i t i c a l point. Theoretically a reduced equation w i l l represent the data of any substance, and a l l that i s required to be known about the substance are i t s c r i t i c a l constants. Although the three reduced equations of state cannot represent data any better than the equations of state themselves, they have been found extremely useful for approximate calculations where no other data are av a i l a b l e . An equation which, according to the calculations of i t s originator represents data exceedingly well over wide ranges, i s the Wohl equation (22), P = RT a V - b ~ V(V - b) T v5 It i s of further Interest because i t contains only three constants x-rtiich can a l l be expressed in terms of the c r i t i c a l constants, - The Keyee equation ( 2 3 ) , V - B ; e--^ V • (V - 172 contains four constants and represents data well over wide ranges. The Beattie-Brldgeman equation (24-), c ) P S RTj l - g T 5 l _ J y 4. B 0 ( l - b) ) - Ao(l - #) V2 ( v) ) y2 V ) contains f i v e constants and i s rather cumbersome. I t repre sents data within experimental accuracy, but has been found - 6 - unsatisfactory for extrapolation,, Many more equations have been proposed but as these have not been successful in the representation of data, or as they are ar b i t r a r y in t h e i r derivation, there i s l i t t l e point in discussing them. (2) Vapor-Pressure Concepts, According to the phase ru l e , when two phases are present i n a one component system, there i s one degree of freedom. Vapor-pressure i s then dependent upon the tempera ture as i s the volume, and s t i p u l a t i o n of the volume i s not necessary when presenting sucn data. The basis of most vapor-pressure equations i s the Clapeyron d i f f e r e n t i a l equation, dp_ m AH • - dT T A V where AH a enthalpy of change of state aV : volume change of state Integration depends upon expressing aH and <aV i n terms of the other two variables and in order to integrate, three assumptions are usually made; (l ) that the latent heat remains constant with temperature, (2) that the l i q u i d volume i s n e g l i g i b l e compared to the vapor volume, and (3) that the perfect gas law i s obeyed i n the gas phase. Integration then yields', i n P = - 4| 1 K RT - 7 - I f an a r b i t r a r y constant i s substituted for AH i t has been found that the equation i s sati s f a c t o r y f o r many compounds from the t r i p l e point to the c r i t i c a l point despite the many approximations i n i t s derivation. For closer representation of experimental data other equations must be resorted t o . If i t i s assumed that the heat of vaporization i s l i n e a r l y dependent upon temperature the following equation, o r i g i n a l l y derived by Rankine ( 2 6 ) , i s obtained, i n P = - f I b log T 4- 0, I t s accuracy i s better than the f i r s t equation as wou^d, be expected. The empirically derived Antoine equation (27) has been f^ound by Thomson (25) to f i t vapor-pressure data of many l i q u i d s extremely well up to reduced temperatures of 0 .05 • The Antoine equation i s , log P = A ^ /•' Although A, B/and C are empirical constants, It has j ' been found that C equals 230 for a large number of organic compounds and that r a r e l y does C equal more than 24b or l e s s than 220. " t " i s the temperature on the centigrade scale. I t i s seen then, that the pressure - temperature relations of a r e a l gas i n equilibrium with i t s l i q u i d are best expressed by empirical equations based on t h e o r e t i c a l considerations, as are the P - V - T re l a t i o n s of a r e a l gas. (.3) The Extension of Thermodynamic Data, Pressure - volume - temperature data has found a p r a c t i c a l use i n applied Chemical Engineering. Not only i s t h i s data of value i n i t s e l f for such things as the c a l c u l a  tion of the dimensions of a gas storage vessel, hut i t i s the foundation of the thermodynamic network r e l a t i n g the f a m i l i a r energy quantities enthalpy, entropy and Internal energy to pressure and temperature. Once the volume has been defined at given temperatures and pressures, i t should be t h e o r e t i c a l l y possible to define a l l other thermodynamic properties, for the s t i p u l a t i o n of only three variables defines any one phase system of constant composition. Variables i n the two phase region may be determined from vapor-pressure data. The various heat quantities are a l l related to pressure, temperature, and volume by r e a d i l y derived thermo dynamic i d e n t i t i e s . Such data when derived are usually tabu lated, or plotted graphically. Three types of graphs are commonly used; these are the pressure - enthalpy (P - H) diagram, the temperature - entropy (T - S) diagram, and the enthalpy - entropy (H - S) or M o l l i e r diagram. The Pressure - Enthalpy Diagram Qu a l i t a t i v e l y the enthalpy usually increases with tem perature and decreases with pressure. The basic equation f o r r e l a t i n g enthalpy changes to other variables i s , AH ^ C p d T + - T (|V) p ) dP This gives the enthalpy change for a given pressure and temperature change. I f the s p e c i f i c heat and P - V - T data are expressed in an equation i t may he possible to i n t e  grate the equation a n a l y t i c a l l y . I f i t i s desired to obtain the isothermal change of enthalpy, the equation s i m p l i f i e s to, P_ AH = 7 }V - T ) dP 4>J OT)P ) Po If P - V - T data can be f i t t e d accurately to a volume-explicit equation the above equation may be integrated. An excellent means of carrying out such an integration was used by Kvalnes and Gaddy (2g). Robinson and B l i s s (29) i l l u s t r a t e d how isothermal enthalpy changes may be evaluated with such pres s u r e - e x p l i c i t equations of state as those of Van der Waals, Wohl, and Beattie and Brldgeman. With Joule-Thompson measurements and s p e c i f i c heat data, use can be made of the following equation for enthalpy changes (30)* OH) - _ Cn ( a T ) QP)T P (SP)H Enthalpy changes in the two phase region can be determined from the Clapeyron equation. The best values are obtained by using the unintegrated form and determining dP as I T accurately as possible either graphically or from a d i f f e r e n  t i a t e d vapor pressure equation accurately representing the data. Thompson (28>) recommends the d i f f e r e n t i a t e d Antoine equation for t h i s purpose* Experimental liquid-and vapor- yolume data up to the c r i t i c a l point<tjfe also required. The Temperature - Entropy Diagram The entropy for the saturated l i q u i d can he obtained from the following equation, where enthalpy values are determined as described i n the l a s t section. The entropy of the saturated vapor i s determined by adding to the saturated l i q u i d value, the entropy of vaporiza tion whioh i s calculated by d i v i d i n g the latent heat by the temperature. Isotherms may be extended into the superheated region by means of the following i d e n t i t y , ("28) . (2>V) (2>P)T " (5T)P. which i s similar to-the enthalpy equation already described. The M o l l i e r Diagram The-Mollier diagram, a p l o t of enthalpy vs. entropy, may be e a s i l y constructed from values determined i n the pre vious sections. - 11 - C. APPARATUS ( 1) Types i n General Use. There are e s s e n t i a l l y two types of apparatus f o r the measurement of pressure - volume - temperature r e l a t i o n s a t hi g h p r e s s u r e : one a constant volume d e v i c e , the other a constant temperature device.' (a) The Constant Volume Apparatus. V a r i a t i o n o f p r e s s u r e w i t h temperature can be measured by the apparatus developed by Keyes ( l ) . I t c o n s i s t s of a s t e e l bomb i n which the sample i s contained over mercury. Pressure Is measured w i t h a dead weight p i s t o n gage, and tem perature Is maintained by a thermostat. Pressure determina t i o n s are made a t v a r i o u s temperatures. T h i s type of apparatus was used by B e a t t i e ( 2 ) and by Sage (3) and i s capable of measuring p r e s s u r e s up to 1 0 , 0 0 0 p . s . i . (4-). (b) The Constant Temperature Apparatus. Pressure - volume isotherms may be determined by an apparatus o r i g i n a l l y used by Andrews ( 5 ) . I t was e x t e n s i v e l y developed by Young (6) and was used by Kay ( 7 ) , Sage (g), and others ( 9 , 1 0 ) . (2) General D e s c r i p t i o n o f the Apparatus. In b r i e f , the apparatus c o n s i s t s o f a compressor, b o l t e d i n a h o r i z o n t a l p o s i t i o n , w i t h three v e r t i c a l branches each c o n t a i n i n g a t h i c k - w a l l e d c a p i l l a r y tube sealed at the - 12 - top. Contained i n one c a p i l l a r y over mercury, i s a sample of the substance under i n v e s t i g a t i o n . The p r e s s u r e i s a p p l i e d by means of a threaded p i s t o n manually operated, and measured by means of the two other c a p i l l a r i e s c o n t a i n i n g a r e f e r e n c e standard f o r which the pr e s s u r e - volume data are known at a give n temperature. Temperature i s maintained constant on the t e s t sample by means of the vapor of a pure o r g a n i c compound b o i l i n g under a constant, reduced p r e s s u r e . E q u i l i b r i u m between l i q u i d and vapor i s brought about by a m a g n e t i c a l l y operated s t i r r e r when making d e t e r m i n a t i o n s i n the two phase r e g i o n . The volume occupied by the sample i s determined by measuring the height of mercury i n the p r e v i o u s l y c a l i b r a t e d c a p i l l a r y by means of a cathetometer. The method i s thus not o n l y a p p r o p r i a t e f o r the mea surement of pressure - volume r e l a t i o n s at constant temperature but f o r the d e t e r m i n a t i o n of vapor-pressures, o r t h o b a r l c d e n s i  t i e s , and c r i t i c a l c o nstants of one or more component systems. (3) C o n s t r u c t i o n and Operation of the Apparatus. (a) The A p p l i c a t i o n and Measurement of Pre s s u r e . The apparatus Is i l l u s t r a t e d i n F i g . I. S t e e l compressor b l o c k A was c o n s t r u c t e d from a p i e c e of 4- i n . by 4- in., bar stock, 13 i n . l o n g . Pressure may be a p p l i e d to the mercury c o n t a i n e d i n A by screwing threaded pi s t l o n< 5 f i r i f o j f e b l o c k . Leakage a l o n g the p i s t o n i s avoided by means of gland E, which was packed at L w i t h g r a p h i t e -THE A P P A R A T U S - 1 3 - impregnated twine (Johns-Manville Mogul C o i l Packing) held In place by nut M bearing on a loose f i t t i n g s t e e l sleeve. Rubber washers backed by an aluminum washer served to keep Joint F leak-proof. Three pressure c e l l s , consisting of three t h i c k - walled, "true-bore" c a p i l l a r i e s are designated by 1, 2 and 3 . Each c a p i l l a r y was 2 mm. i n inside diameter, 8" mm. i n outside diameter, and 3 5 i n . long. C a p i l l a r y 1 contained the sample under investigation, while 2 and 3 contained pure nitrogen, the reference standard. C a p i l l a r y 3 * s used for low pressure measurements, while 2, which has an enlargement at the bottom to contain nitrogen at low pressures serves as a high pressure gage. Ca p i l l a r y 3 was c a l i b r a t e d for pressure measurement by means of a mercury manometer i n position 2 , and c a p i l l a r y 2 was c a l i b r a t e d for high pressure: A by not i c i n g the mercury l e v e l i n 3 and 2 simultaneously at some suitable Intermediate pressure. Both nitrogen-containing c a p i l l a r i e s are maintained at 0° C. by means of an ice-water bath (D) surrounding them, and deviations of nitrogen from the gas law are corrected for by using the data of Smith and Taylor ( l l ) f i t t e d to the Keyes equation. This data agrees well within the accuracy required, with the data of B a r t l e t t ( 1 2 ) , Amagat ( 1 3 ) , Holborn (14-), Verschoyle ( 1 5 ) , Onnes (lb) and Michels ( 1 7 ) . The d e t a i l s of the packing for c a p i l l a r i e s 1 and 3 are shown i n the i n s e r t . The c a p i l l a r i e s are secured by - 14- - nut "d", s t e e l washer "c", and rubber washers "h", bearing against enlargement " f " on the c a p i l l a r y . The enlargement i s cushioned i n steel cup "e" with rubber washers "b". Leakage around the cup Is avoided by means of rubber washer "g". (b) The Maintenance and Measurement of Temperature. The temperature i s maintained constant around c a p i l  l a r y 1 with the vapor of a pure organic compound b o i l i n g under a fixed, reduced pressure. The l i q u i d s o r i g i n a l l y used by Young (18") for t h i s purpose are used. The entire range of temperature from 2 5°C. to 3 5 3°C. can be obtained by b o i l i n g the following l i q u i d s under various pressures up to atmos pheric. Compound Lower Temperature °c. Higher Temperature °c. Carbon d i s u l f i d e 2 5 4-6 Ethyl alcohol 4 ? 7 * Chlorobenzene 7 9 1 3 2 Bromobenzene 133 1 5 5 Aniline 1 5 6 134- Methyl s a l i c y l a t e 185 222 1-bromonaphthalene 2 2 3 280 Mercury 231 353 The higher temperature i s the approximate normal b o i l i n g point of the compound. The lower temperature was obtained by reducing the pressure. - 15 - The b a t h i t s e l f c o n s i s t s o f a v a c u u m - J a c k e t t e d d i s t i l  l a t i o n column (H) which i s c o m p l e t e l y s i l v e r e d except f o r two v e r t i c a l o b s e r v a t i o n s t r i p s d i a m e t r i c a l l y opposed . The column i s f o u r f e e t l o n g and one i n c h i n i n t e r n a l d i a m e t e r . E x p a n s i o n b e l l o w s on the upper h a l f o f the column are d e s i g n e d to accommodate a t emperature d i f f e r e n t i a l o f 3^0°C. from the i n n e r to the o u t e r column . The u s e f u l l e n g t h o f the column i s two f e e t . Vapors r i s e i n t o the column from the 500 m l . b o i l i n g f l a s k (G-) and condensate r e t u r n s a t ( K ) . Attachment ( I ) c o n  s i s t i n g o f a f i n e l y drawn out tube i n s e r t e d t h r o u g h a s t a n d a r d t a p e r J o i n t serves to a v o i d bumping i n the b o i l i n g l i q u i d . Heat i s s u p p l i e d to the f l a s k by means o f an a s b e s t o s i n s u l a t e d , n ichrome, h e a t i n g m a n t l e . c o n n e c t e d to. a v a r l a c and capable o f d e l i v e r i n g 300 wat ts a t 110 v o l t s . The upper h a l f o f the f l a s k , and the s i d e arm to the column are hea ted w i t h a nichrome element i n s u l a t e d w i t h a s b e s t o s . The maximum heat i n p u t to t h i s element i s 200 w a t t s . In o r d e r to m a i n t a i n the p r e s s u r e and thus the tem p e r a t u r e c o n s t a n t , a manostat a f t e r t h a t o f M c C o n n e l l (19) was c o n s t r u c t e d . I t c o n s i s t s o f g l a s s hoop ( R ) , c o n s t r u c t e d from 10 mm. d iameter p y r e x t u b i n g , e l ec tromagnet a c t i v a t e d b l e e d v a l v e (U) and an e l e c t r o n i c r e l a y ( F i g , I I ) . Whi le the a p p a r a t u s i s b e i n g evacuated by means o f an a p i r a t o r , the cock (Q) i s c l o s e d at the r e q u i r e d p r e s s u r e . As e v a c u a t i o n c o n t i n u e s , the s u l f u r i c a c i d c o n t a i n e d i n the hoop - l b - r i s e s In the left leg breaking contact at (S). This activates the relay magnet (Fig. II) and causes the electromagnet to p u l l up the plunger covering the 2 mm. opening. When the a i r rushes i n , contact at (S) i s remade and the relay shuts o f f the valve. Sudden pressure pulses are dampened by surge bo t t l e s (V) and the absolute pressure i s indicated by manometer (0). Several improvements upon the o r i g i n a l suggestions of McConnell have been incorporated to give a greater degree < of control and to f a c i l i t a t e the setting of the apparatus. . Sulf u r i c acid of s p e c i f i c gravity 1.71 has been suggested by Morton (20) as being more sensitive than mercury because of i t s lower density. In addition i t i s not contami nated on i t s surface as i s mercury. Although a coarse adjustment can be obtained by closing cock (Q), a f i n e r adjustment was found necessary and was incorporated i n the form of a f l e x i b l e tube (W) and screw adjustment (X) by which the glass hoop could be rotated about the f l e x i b l e tube as centre. In t h i s way extremely small changes i n pressure could be obtained by merely adjusting (X) with (Q) closed. Bleed valve plunger (tf) consists of a brass strap serving as a spring and a lever arm to which i s secured a bolt cojvered with a soft rubber pad. / I t was found necessary to use an electronic relay because the tungsten - s u l f u r i c acid contact resistance was extremely high and because e l e c t r o l y s i s of the s u l f u r i c acid O U T P U T To B L E E D V / ^ L V E 9 ? *1 4 0 y. DC A C T I V A T O R . + ' 1 1 0 v. D.C/ - Fig - 2 CIRCUIT DIAGRAM O F THE ELECTRONIC RELAY • - 17 - would occur at f i n i t e c u r r e n t and d i s t u r b the s e t t i n g o f the hoop. A c i r c u i t diagram of the r e l a y i s shown i n F i g . II. I t s main f e a t u r e s c o n s i s t of the 50L6 GT pentode, and an electromagnet operated c i r c u i t b reaker. F o r t y v o l t d i r e c t c u r r e n t i s made and broken as c o n t a c t i s broken and made by the a o t i v a t o r changing the g r i d b i a s . .The temperature of the vapor bath was measured to the nearest 0.1°C. by means of a copper constantan thermel p r e  v i o u s l y c a l i b r a t e d over the range of use, and a Leeds and Northrup type K -2 potentiometer (see P r o c e d u r e s ) . The thermel was c o n s t r u c t e d from Leeds and Northrup g l a s s i n s u l a t e d thermel wire, and was p r o t e c t e d from the vapor by a pyrex tube (AA) the end of which was blown very t h i n and p r o t e c t e d from condensate by a s h i e l d , (e) The Measurement of Volume. The volume o c c u p i e d by the samples i n the c a p i l l a r y was determined by measuring the l e v e l of the mercury w i t h a cathetometer. T h i s h e i g h t was t r a n s l a t e d : i n t o volume u s i n g the c a l i b r a t i o n data p r e v i o u s l y o b t a i n e d . (d) C o n s t r u c t i o n and O p e r a t i o n of the S t i r r i n g D evice. To b r i n g about speedy e q u i l i b r i u m i n tube 1 i n the two phase r e g i o n , the sample i s s t i r r e d w i t h a p i e c e of s t e e l 2 cms. i n l e n g t h and 1 .5 mm. i n diameter. T h i s p i e c e of s t e e l i s drawn up and down i n s i d e the tube by means of electromagnet fl£). The magnet i s wound on a hollow b r a s s magnet form from lbOO t u r n s of 2 2 gage, double c o t t o n - c o v e r e d magnet wire, and c a r r i e s a c u r r e n t o f 3 » 5 amperes. The magnet i s suspended from two l e n g t h s of 200 pound t e s t n y lon l e a d e r which runs up over two p a i r s of p u l l e y s (not shown) then down to a r o t a t i n g wheel d r i v e n through a 3 2:1 r e d u c i n g gear by a 1800 RPM motor. One complete c y c l e i s made i n about one second. - 19 - D. PURIFICATION OF MATERIALS ( l ) The G-eneratlon and P u r i f i c a t i o n of Nitrogen. (a) Apparatus. Because commercial tank nitrogen contains s i g n i f i c a n t quantities of the unreactive gases such as argon, i t cannot hie p u r i f i e d with chemical reagents. However, nitrogen 1chemically produced i s capable of f a i r l y easy chemical p u r i f i c a t i o n by absorption of impurities from i t i n a gas p u r i f i c a t i o n t r a i n . An excellent way i n which nitrogen can be thus generated and p u r i f i e d i s that of Smith and Taylor (31) and a modification of t h e i r apparatus was used and i s shown i n Fig. I I I . The nitrogen i s produced i n f l a s k (A) from the reaction of saturated KNOjg with saturated (NH^igSO^, dropping funnel (B) containing the K N O 2 . Mercury reservoir (C) serves to r e l i e v e excess pressure. Nitrogen passes f i r s t into scrubber (D) which con tains a solution to absorb the oxides of nitrogen. The solution has the following composition (32): 15$ anhydrous FeSO^ 15% H2S0i^ ( 6 W 70% water Although Smith and Taylor did not use a reagent to remove the oxides of nitrogen, i t was noticed that they were produced i n perceptible quantities and provision was made for th e i r removal as i t was i n a sim i l a r apparatus (33)» NITROGEN GENERATION AND PURIFICATION TRAIN From t h i s scrubber the nitrogen passes into a bottle containing Fleser's solution (3^)» an oxygen absorbent having the following composition: Na 2S 20k (g6.7#) 16 gm. NaOH (stick) 1 3 . 3 gm. Anthraquinone-B-sulfonate (35%) 4- gm. H 20 100 gm. This s o l u t i o n i s not only a more e f f i c i e n t absorbent than pyr o g a l l o l but does not give o f f undesirable by-products such as C0 2. Further, the solution Is blood red when fr e s h l y compounded and brown when spent. The nitrogen next passes Into a solution of concen trated H2S0ty, F, which absorbs the bulk of the water vapor present, and then through 10% NaOH, G-, which absorbs C0 2 and further moisture. Remaining quantities of water are removed i n bottle H, containing KOH p e l l e t s , and bottle J , contain ing P2O5. Mercury reservoir K serves to r e l i e v e excess pressure. Liquid a i r trap L cools the nitrogen before i t enters d i s t i l l a t i o n stage M and N. In the f i n a l stage nitrogen i s f i r s t condensed i n the reservoir at M. This i s accomplished by bubbling tank hydrogen into commercial l i q u i d nitrogen contained i n the Dewar f l a s k surrounding the reservoir, and by keeping the pressure i n the reservoir three to four inches of mercury above atmospheric pressure by r a i s i n g mercury r e s e r v o i r K. Next the n i t r o g e n i s g e n t l y b o i l e d and the vapors allowed to escape to the atmosphere f o r a few minutes. The middle f r a c t i o n i s then d i s t i l l e d i n t o bulb N, and the residue i s b o i l e d o f f to the atmosphere, (b) Procedure* Heat i s s u p p l i e d to f l a s k A by means of a 250 watt heat lamp c o n t r o l l e d by a v a r i a c . With valve (a) closed KN02 i s allowed to drop slo w l y from the funnel u n t i l n i t r o g e n bubbles out through the mercury at C. At t h i s point M (a) i s c a r e f u l l y opened to a l l o w passage of nitrogen through the t r a i n . A f t e r the n i t r o g e n bubbles out at K, the d i s t i l l a t i o n procedure begins. Hydrogen i s f i r s t allowed to bubble i n t o f l a s k M co n t a i n i n g l i q u i d n i t r o g e n , while (b) remains c l o s e d . When about 50 ml. of l i q u i d n i t r o g e n has accumulated, the hydrogen i s passed through N, and M i s slowly lowered. With (b) closed and (e) and (c) open, the f i r s t 5 ml, i s l e t out to the atmos phere. Then (e) and (c) are c l o s e d and (b) opened. The middle f r a c t i o n i s b o i l e d over to N and f i n a l l y the l a s t 5 ml, are l e t out i n t o the atmosphere. I t was n o t i c e d that the l i q u i d i n M had a b l u i s h cast and upon c l o s e r i n s p e c t i o n , i t was found t h a t the bottom of the r e s e r v o i r was l i n e d w i t h a blue s o l i d . This s o l i d v aporized i n t o a brown gas when the f i n a l p o r t i o n of the ni t r o g e n was l e t to the atmosphere. The gas was o b v i o u s l y NOg - 2 2 - An inspection of the scrubber bo t t l e D showed that the solution was dark brown i n color where previously i t had been l i g h t green. The solution had obviously become saturated and the oxides had been car r i e d through the t r a i n . Upon a l l subsequent d i s t i l l a t i o n s i t was noticed that the l i q u i d i n the rese r v o i r was water-white i n d i c a t i n g that the d i s t i l l a t i o n procedure had been e f f e c t i v e i n eliminating the colored impurity. The l i q u i d was stored i n reservoir N u n t i l i t was used to f i l l the c a p i l l a r i e s . (2) The P u r i f i c a t i o n of Mercury. Mercury with v i s i b l e scum on the surface was f i r s t f i l t e r e d through a funnel the stem of which was drawn out into a fine c a p i l l a r y . It.was then allowed to f a l l from a similar funnel into a scrubber four feet long containing 10% NaOH, to remove grease. Acid reactive metals and t h e i r oxides were next removed i n a similar scrubber containing 15$ n i t r i c acid. The mercury was f i n a l l y washed i n d i s t i l l e d water. The water was removed from the mercury by decanta- tion and then by vacuum desication. The mercury was d i s t i l l e d three times i n vacuum to remove the heavy metals. The mercury thus obtained was mirror-like i n com plexion, had no v i s i b l e surface impurities, and did not form a scum on the glass container upon prolonged standing. - 23 - The mercury was stored i n narrow-necked, ground glass stoppered bottles i n a dark cupboard, (3) P u r i f i c a t i o n of Organic Compounds. (a) Apparatus. Most of the compounds used were o r i g i n a l l y C,P. and were d i s t i l l e d once. The d i s t i l l a t i o n column used was, vacuum-Jacketted and sil v e r e d . I t was packed for i t s two foot length with 1/3 i n . pyrex he l i c e s , and was equivalent to t h e o r e t i c a l p l a t e s , A stopcock on the product l i n e could be adjusted to vary the take-off and r e f l u x . Drip counters were placed on the r e f l u x l i n e and on the product l i n e and the re f l u x r a t i o could thus be estimated. A vacuum adapter was placed on the product l i n e which made i t possible to remove the product f l a s k at any time without disturbing the vacuum on the system to any great degree. Provision was made to hang a thermometer i n the path of the ascending vapor. The stopcock on the product l i n e was lubricated from the outside with aplezon and did not leak perceptibly. Heat was supplied to the two l i t r e b o i l i n g f l a s k by a zipper heating mantle completely enclosing the f l a s k , supplied with current from a vari a c . - 24- - The helices were added to the column one at a time, a l l incomplete and chained heli c e s being discarded. Only i n this manner can the most e f f i c i e n t use be made of the packing, (b) Procedure. Most of the compounds used were C.P, and a l l were fractionated once with the exception of bromonaphthalene. In an e f f o r t to obtain constant pressure d i s t i l l a t i o n two d i f f e r e n t types of manostat were used but were found unsatisfactory, for they gave too sudden pressure surges. It was decided, therefore, to use a vacuum pump d i r e c t l y f o r d i s t i l l a t i o n of the high b o i l i n g compounds such as methyl s a l i c y l a t e and higher, and to use the aspirator for the rest except carbon d i s u l f i d e which was d i s t i l l e d at i t s normal b o i l i n g point. It was noticed that the pressure slowly f e l l as the d i s t i l l a t i o n proceeded making i t impossible to assign a d i s  t i l l a t i o n temperature but at the same time not being sudden enough to disturb the equilibrium. In each d i s t i l l a t i o n , the d i s t i l l a t e upon f i r s t being condensed was allowed to run into the product b o t t l e . The stopcock was then closed and the column operated at t o t a l r e f l u x for one half hour a f t e r which the d i s t i l l a t e was run to the product bottle at f i n i t e r e f l u x r a t i o . When approximately 25$ of the o r i g i n a l charge had been collected, the product b o t t l e was removed, and a clean bottle put in i t s place. As the d i s t i l l a t i o n proceeded, the reflu x r a t i o was raised to make up for the changing - 25 - composition of the material i n the b o i l e r . A b r i e f summary of the conditions of d i s t i l l a t i o n and physical properties of the substances are given below with references. The bracketed Indices are taken from the Handbook of Chemistry and Physics, Carbon d i s u l f i d e (technical grade) (35, 36) Pressure: atmospheric Temperature: 4-b".0°to 4-b.l°C. Properties: water-white Chlorobenzene (C.P.) (37) Pressure:. 24- mm. Temperature: 58.0°to 59.0°C. Properties: N D 20- m 1.5243 (1.524.7), water-white Bromobenzene (C.P,) (33) Pressure: 24- mm. Temperature: 58.0°to 59.0°C. Properties: N D 2 0 . m 1 # 5 5 9 3 ( 1 # 55977) Aniline (reagent grade) ( 3 9 - ^ 2 ) Pressure: 6 mm. Temperature: 62.0°to bJ.0oC. Properties: ND20 = i.5gb4- (1.5863) Color: dark red, v i s i b l e water. D i s t i l l e d from zinc dust. The pure a n i l i n e was stored over activated alumina. Methyl s a l i c y l a t e (U.S.P.) Pressure: 3 i m » Temperature: 73°to 76°C. Properties: ND20 = l.b369 (1.5369) water-white In each d i s t i l l a t i o n the charge equalled about one l i t r e and the middle 50 to 60% was coll e c t e d . The r e f l u x r a t i o went from 4-: 1 to 6:1 . 1-bromonaphthlene (C.P.) was not p u r i f i e d f o r i t s index of r e f r a c t i o n agreed with the accepted value of N D 2 0 » 1 . 6 5 8 2 . The r e f r a c t i v e indices were taken by means of an Abbe refractometer c a l i b r a t e d with reference standards. The i n s t r u  ment was maintained within the temperature l i m i t s of . 1 ° C . by means of c i r c u l a t i o n from a constant temperature bath. A l l the compounds are stable and e a s i l y stored, with the exception of a n i l i n e which i s not only hygroscopic, but unstable i n sunlight and a i r . The a n i l i n e was stored In a dark, narrow-necked, ground glass stoppered bottle over activated alumina. The bottle was placed i n a dark cupboard. (4-) The P u r i f i c a t i o n of Normal - Butanol. Although the e f f e c t of pu r i t y on P - V - T measure ments i s comparable with i t s e f f e c t on the determination of most physical properties, the accurate determination of the c r i t i c a l temperature and pressure i s considerably effected by the p u r i t y of the sample. For t h i s reason i t was necessary to carry out a careful and thorough p u r i f i c a t i o n . From twenty l i t e r a t u r e references, seven were chosen as a guide because of t h e i r thorough description and the con sistency of the physical constants used as a c r i t e r i o n of purity (4-3 - 4-9). The a r t i c l e of Brunei, Crenshaw and Tobin was exceedingly valuable f o r i t discussed several methods the authors t r i e d , and compared the products of each method. - • 2 7 - The p u r i f i c a t i o n can he broken into two steps; eliminating the organic impurities, and eliminating water. As water i s e a s i l y picked up from the a i r , i t was decided to remove i t l a s t . Complicated procedures involving contacting the alcohol with several reagents such as sodium hydrogen s u l f i t e , hydrochloric acid, sodium hydroxide, as well as desiccants, as was c a r r i e d out by Harkins, by Webb, and by Ernst, were d i s  carded in favor of the more straightforward procedure of Brunei et a l , involving several fractionations, and contact with desiccants, « The work of Brunei showed that calcium oxide was the best desiccant compared to abdium, barium oxide and calcium. In addition i t was decided r>o use magnesium (which had been used i n most of the other references) and activated alumina, i^iot only does activated alumina absorb water better than phosphorous pentoxide and s u l f u r i c acid, but i t absorbs trace organic impurities. The apparatus and procedure are described below, (a) Apparatus. The d i s t i l l a t i o n apparatus consisted of a vacuum- jacketed, silvered, d i s t i l l a t i o n column, packed for i t s four- foot length with 1/8 i n . pyrex h e l i c e s . Its f r a c t i o n a t i n g power i s equivalent to 2 0 t h e o r e t i c a l plates. Reflux and take-off could be adjusted by means of one stopcock on each of two product l i n e s and use could be - 28 - made of both product bottles during a single d i s t i l l a t i o n , one for primary overhead and the other for the main product. A thermometer reading i n tenths of a degree c e n t i  grade was suspended i n the path of the vapor. The two-litre b o i l i n g f l a s k was heated with a G-las- col mantle controlled by a va r i a c . The s t i l l was used only f o r the p u r i f i c a t i o n of normal - butanol to eliminate any p r o b a b i l i t y of contamination, (b) Procedure. Two l i t r e s of chemically pure butanol, f a i n t l y amber i n color were d i s t i l l e d at 60 mm. of mercury pressure and one l i t r e c o l l e c t e d . The d i s t i l l a t e was water-white i n color; the residue amber. The d i s t i l l a t e was refluxed with 100 gm. of calcium oxide for eight hours and d i s t i l l e d at atmospheric pressure with a high r e f l u x r a t i o . The middle 60$ was c o l l e c t e d . This was refluxed with two grams of reagent grade magnesium f o r eight hours and d i s t i l l e d at high r e f l u x at atmospheric pressure. The middle 75$ was c o l l e c t e d i n the range l i b . 8 - .9°C./750 mm. The d i s t i l l a t e was refluxed for eight hours with activated alumina heated overnight at 175°C. for a c t i v a t i o n . The temperature of d i s t i l l a t i o n was 117.2°C. and the middle 60$, or 300 c c . was c o l l e c t e d . The butanol was stored over alumina i n the product f l a s k . The index of r e f r a c t i o n at 20°C. was 1.3992, the l i t e r a t u r e values being 1.3990 (4b), 1.39929 (51), 1.3998 (52), 1.3992 (53, 55), 1.3994-•(540. The Index of r e f r a c t i o n at 25°G. was 1 .397 4 , the l i t e r a t u r e values being 1.397^ (^3, 4-7). and 1.3975 ( ^ , 56). - 30 - E. PROCEDURES AiMD RESULTS (l ) Calibration of the Thick-Walled C a p i l l a r y Tubes. The pressure c e l l s bore the trade mark "true-bore" and were the product of the Fischer and Porter Company. The purpose of the c a l i b r a t i o n was to determine the Internal volume of the c a p i l l a r y between fix e d points along i t s length. The method consisted of weighing the quantity of pure mercury required to f i l l the tube between two points whose distance apart was measured with a cathetometer. To the end of the tube which would be l a t e r sealed was attached a straight-bore stopcock, the free arm of which was drawn out to a f i n e t i p . The tube was then clamped in a v e r t i c a l p o sition with the cock on the bottom. The top of the tube was attached to a vacuum pump. Before the operation was started, the tube was cleaned by running through i t in succession, chromic acid, d i s t i l l e d water, ethyl alcohol, and carbon t e t r a c h l o r i d e . The stopcock core was then c a r e f u l l y greased only at Its extremities, and not close to the centre. The core was placed in p o s i t i o n and worked well in by rotating i t . As the grease spread out, carbon tetrachloride was run through the tube and the stopcock rotated quickly. This was repeated several times u n t i l there was l e f t only a thin coating of grease at the extremities which did not spread towards the centre upon pro longed turning. The carbon tetrachloride was evaporated with - 3 1 - a stream of tank nitrogen. The actual c a l i b r a t i o n was carr i e d out by pla c i n g beneath the cock a previously weighed weighing bottle contain ing about bO gms. of p u r i f i e d mercury. With the cock closed, the pump was started and then turned o f f , the cock opened to allow the mercury to r i s e Just above i t , the cock closed, and a i r admitted to above the mercury. With the cathetometer a reading was taken of the bot tom of the meniscus to 0.01 mm., and of the height of the meniscus to ,005 mm. by means of the micrometer. The height reading was referred to a glass marker attached to the c a p i l  l a r y . The bottle was now weighed and placed beneath the cock, the cock opened to allow the mercury to f a l l s l i g h t l y , and the pump turned on u n t i l the mercury rose to a new p o s i t i o n roughly one centimeter above i t s former l e v e l . The process of drawing the mercury up and weighing the bottle was continued u n t i l the mercury l e v e l reached the top of the tube. The volume of the tube from the f i r s t l e v e l to each higher l e v e l was then computed. This was done by determining the net weight of mercury required to f i l l the tube between the two le v e l s , or the difference i n the weight of the bottle when the mercury stood at the lowest l e v e l and i t s weight when the mercury stood at a higher l e v e l . The net weight was corrected for a i r buoyancy. This net weight of mercury represented the volume occupied between the two le v e l s concerned, plus the volume occupied by the meniscus at the higher l e v e l , minus the volume of the meniscus at the base or f i r s t l e v e l (a constant amount). To f i n d the true value of the volume of the c y l i n d r i c a l sec tio n , the volume occupied by the two menisci were computed from data in the International C r i t i c a l Tables (,50)-.- This data was plotted graphically and the volume corresponding to a given meniscus height was read from the graph. The volume of mercury was corrected to the tempera ture recorded by a thermometer placed i n the mercury from time to time. The c a p i l l a r y a f t e r being calib r a t e d was sealed o f f at the end containing the stopcock, and the volume of the t i p was determined by pouring through a h a i r l i k e tube to the bottom of the c a p i l l a r y , a weighed amount of mercury. Three determinations were made and the mean taken. {It i s estimated that the absolute volume of a l l sections ten centimeters or longer i s known within 0,1% or l e s s . . - 33 - (2) Calibration of the Thermel. The thermel was c a l i b r a t e d i n p o s i t i o n i n the bath against a platinum resistance thermometer the head of which was located- d i r e c t l y beneath the thermel. "T>vfe. 2.5 ohm p l a t i  num thermometer used - S e r i a l No. 317863 - was c a l i b r a t e d i n 1939 by the National Bureau of Standards. I t checked at the ice point to within o.OOOl ohm of the value recorded on the N.B.S. c e r t i f i c a t e ; . During c a l i b r a t i o n the cold Junction was submerged in a Dewar f l a s k containing melting i c e . The c a l i b r a t i o n s were carried out at four widely spaced groups of temperatures; 0°C., 25°C., 14-0 and 150°, and 190, 200, 210 and 220°C. and a graph was plotted of the devia tions of the values from the accepted values given In the Wheelco b u l l e t i n (57). The points f e l l on a smooth curve, the general shape of which i s t y p i c a l of thermel deviations. The deviations i n the operating range go from 31 to 38 micro v o l t s , a spread of ,l4-°C. The temperature of the bath was within the l i m i t s of 0.01°C. during a l l c a l i b r a t i o n s . (3) Loading the C a p i l l a r y with an A i r Free Sample of Butanol. The method was a modification of Young's (b). ; In Fi g . IV the c a p i l l a r y i s attached by means of a mercury seal to the neck of a round-bottomed f l a s k containing mercury. A small test-tube containing the sample of butanol i s attached by means of a standard taper Joint to a tube sealed to the - 3^ - top of the f l a s k . To f i l l the c a p i l l a r y with the butanol, the f l a s k was f i r s t clamped with the bent part of the neck In a v e r t i c a l p o s i t i o n pointing downward. The c a p i l l a r y , which contained the previously cleaned and polished hard s t e e l s t i r r e r , was put i n place and the mercury seal assembled. Clean mercury was then poured through the stopcock and the cock greased with apiezon. The f l a s k was Joined to a high vacuum l i n e and with the small test tube i n place, evacuated at 10"^ mm. f o r eight hours. The tube was then removed, f i l l e d with butanol, and replaced. Evacuation was continued and large bubbles could be seen r i s i n g from the butanol f o r about ten minutes, a f t e r which no bubbles were seen to r i s e even though the butanol was at Its b o i l i n g point. This indicated that surface evacua tion was taking place and that the sample was a i r free. A Dewar tube f u l l of dry ice was next placed at the t i p of the c a p i l l a r y and the butanol allowed to d i s t i l over. After a small amount had accumulated, evacuation was continued while the dry i c e was removed. In t h i s way i t was hoped to remove any l a s t traces of a i r . F i n a l l y the dry ice was replaced and the butanol d i s t i l l e d over, i t taking about two days to accumulate two inches of the sample. During t h i s time the cock was opened frequently to sweep out the f l a s k . The fact that the f i l l i n g apparatus was a i r - t i g h t was Indicated when the cock was closed overnight, for upon reopening the cock, no perceptible sound could be heard from the pump* The mercury was s p i l l e d into the c a p i l l a r y by tip p i n g the apparatus, and a i r was allowed i n . The tube was then.loaded into the compressor. (k) Loading the C a p i l l a r i e s with Pure Nltro^f»n. Previously p u r i f i e d nitrogen (see P u r i f i c a t i o n of Nitrogen) was used to f i l l the c a p i l l a r y employing a s i m i l a r apparatus as that used to load the butanol c a p i l l a r y . This apparatus was attached to the end of the nitrogen t r a i n and before nitrogen was f i n a l l y admitted, the c a p i l l a r y was a l t e r  natively evacuated and f i l l e d with nitrogen u n t i l a l l gases were purged out. At t h i s point the mercury was s p i l l e d into the c a p i l  l a r y and the apparatus dismantled. The open end of the tube was placed i n a beaker of mercury and i n order to f i l l the reservoir with nitrogen, a f i n e , h a i r l i k e tube was Inserted,, into the c a p i l l a r y beneath the l e v e l of the mercury, and nitrogen admitted from the p u r i f i c a t i o n t r a i n . The tube was then loaded Into the compressor block. - 36 - F. SUMMARY AND RECOMMENDATIONS The compression apparatus has been constructed as described and I l l u s t r a t e d , and a l l the a u x i l i a r y apparatus has been found successful i n operation. One high pressure tube has been f i l l e d with normal - butanol, as described, and another tube has been f i l l e d with nitrogen generated and p u r i f i e d i n the p u r i f i c a t i o n t r a i n . However, i t has been shown that the method of packing i s as yet unsatisfactory, for breakage of the c a p i l l a r i e s occurred as they were being secured i n p o s i t i o n . The compounds for use i n the constant temperature bath have been adequately p u r i f i e d ; the c r i t e r i o n being that they worked s a t i s f a c t o r i l y i n providing a constant temperature; The bath i t s e l f has proved successful i n operation, f o r the thermel was adequately calibrated, and the degree of control provided by the bath was shown by the platinum resistance thermometer to be constant within the l i m i t s of 0.01°C, The magnetically operated s t i r r e r has been t r i e d and shown to work s a t i s f a c t o r i l y . In preparation for actual experimental determinations, normal - butanol has been c a r e f u l l y p u r i f i e d . The t h e o r e t i c a l and p r a c t i c a l importance of the data when i t i s determined has been i l l u s t r a t e d . I t i s recommended that a dead-weight piston gage be Ins t a l l e d and used i n the place of the nitrogen piezometers. - 37 - Such a gage w i l l eliminate the error in pressure tube c a l i  bration, and i n using the experimentally determined nitrogen data. Some minor modification should be made In the packing arrangement i n order to prevent future breaking of the pressure c e l l s . The inclusion of more soft rubber washers between the cup and the steel washer seems to be the best way of doing t h i s . Any modification should be f i r s t tested on blanks-made up for that purpose, before a c a p i l l a r y tube I t s e l f i s t r i e d . Once such an adequate arrangement has been made, the apparatus as i t stands promises to be f u l l y s a t i s f a c t o r y f o r the determinations planned. 38" BIBLIOG-RAPHY (1) Keyes, Proc. Am. Acad. Arts S c i . b8, 505 (1933) (2) Beattie, Proc. Am. Acad. Arts S c i . 69, 389 (193 )^ (3) Sage, Ind. Eng. Chem. 2b, 1218 (193*0 (4-) Sage, Trans. Am. Inst. Mining Met. Engrs. .136, 136 (194-0) (5) Andrews, P h i l . Trans. Roy. Soc. 159, 575 (1809) (6) Young, "Stoichiometry", pp. 132 f . f . , London, .Longmans, Green & Co., (1908) (7) Bahlke and Kay, Ind. Eng. Chem. 24-, 291 (1932) . (8) Nysewander, Sage, and Lacey, Ind. Eng. Chem. 32, 118 (194-0) (9) Vaughan and Graves, Ind." Eng. Chem. 32, 118 (1940) (10) Gornowski, Amick and Hixson, Ind. Eng. Chem. 39, 134-8(194-7) (11) Smith and Taylor, J . Am. Chem. Soo. 4-5, 2107 (1923) (12) B a r t l e t t , J . Am. Chem. Soc. 4-9, 687 (1927) (13) Amagat, Ann. Chim. Phys. ( b ) , 29, 68 (1893) (14-) Holborn, Ann. Physik, 63, 674- (1920) (15) Verschoyle, Proc. Roy. Soc. 111A, 552 (192b) (16.) Onnes, Comm. Phys. L ab. Leiden, No. I69D C192M-) (17) Mlchels, Wouter and de Boer, Physica, 3. 585 (.19-36) (18) Ramsay and Young, Trans. Chem. Soc, b4-0, (1885) (19) McConnell, Ind. Eng. Chem., Anal. Ed., J, 4-, (1935) (20) Morton, "Physical Methods of Organic Chemistry". (21) D i e t e r l c i , Ann. Phys., 11,700 (1899) t22) Wohl, Z. Physik. Chem., 87, 1 (1914-) (23) Keyes, Proc. Nat. Acad. S c i . , 3, 323 (1917) (24-) Beattie and Brldgeman, Proc. Am. Acad. Arts S c i . , b3, 229 (1928) (25) Thomson, Chem. Revs., 38, 23 (194-b) 31 (2b) Rankine, Edinburgh New P h i l . J . , 94-, 235 (134-9) (27) Antoine, Compt. Rend., 107, 631 (1883) (23) Kvalnes and G-addy, J . Am. Chem. S o c , 53, 397 (1931) (29) Robinson and B l i s s , Ind. Eng. Chem., 32, 396 (19^0) (30) G l l l i l a n d and Lukes, Ind. Eng. Chem., 32, 957 (19*10) (31) Smith and Taylor, J . Am. Chem. S o c , 4-5, 2107 (1923) (32) Mellor, Vol. VIII, p. 4-23 (33) Klnoshita and Oishi, P h i l . Mag. 24-, 52 (1937) (34-) L. F. Fieser, J . Am. Chem. Soc., 4-6, 2639 (1924-) (35) J . Am. Chem. Soc., 4-4-, 108 (1922) (36) J . Am. Chem. S o c , 59, 500 (1937) (37) Tlmmermans and Martin, J . chlm. physique, 23, 74-5 (1926) (33) Audsley and Goss, J . Chem. Soc., 864- (194-1) (39) Ind. Eng. Chem., 12, 331 (l920) (4-0) Anderson and Gilbert, J . Am. Chem. S o c , 64-, 2369 (194-2) (4-1) Waldemar, Ziegler and Andrews, J . Am. Chem. S o c , 64-, 24-83 (19^2) (4-2) Few arid Smith, J . Chem. Soc,, 753 (194-9) (4-3) Brunei, Crenshaw and Tobin, J . Am. Chem. S o c , 4-3, 5bl (1921) (4-4-) Harklns and Wampler, J , Am. Chem. Bop.., 53, 850 (1931) (4-5) Jones and Christian, J . Am. Chem. S o c , 61, 32 (1939) (4-6) Webb and Lindsley, J . Am. Chem. S o c , 56, 371!- (193*0 (4-7) Allen, Lingo and Felsing, J . Phys. Chem., 4-3, 4-25 (1939) (4-3) Williams and Daniels, J . Am. Chem. S o c , ^6, 903 (1924-) (4-9) Ernst, Litkenhous and Spanyer, J . Phys. Chem., 36, 34-2 (1932) (50) Int. C r i t . Tables, 1:72 (51) Vogel, J . Chem. S o c , 1814- (1948) (52) Butler, Ramchandani and Thomson, J . Chem. S o c , 280 U935) (53) Smith and Walls, J . Am. Chem, S o c , 53, 2115 (l93l) (540 Smyth and Engel, J• Am, Chem. S o c , 51, 2646 (1929) (55) Cox, J . Chem. S o c , 119, 152 (1921) (56) Trew and Watkins, Trans. Farad. S o c , 29, 1310 (1933) (57) Wheelco B u l l e t i n T/C 1 

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