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Physical constants of some long-chain normal paraffin hydrocarbons Buckland, John Alexander Channing 1947

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111?An $ PHYSICAL CONSTANTS OP SOME LONG-CHAIN NORMAL PARAFFIN HYDROCARBONS by JOHN ALEXANDER CHANNING BUCKL1ND A Thesis Submitted i n P a r t i a l F u l f i l l m e n t of the Requirements f o r the Degree of MASTER OF APPLIED SCIENCE i n the Department of CHEMICAL ENGINEERING The U n i v e r s i t y of B r i t i s h Columbia March 1947 ifyA ^^U^^ ACET0WI3DGEMBHT I wish to acknowledge the h e l p f u l advioe of Dr. W. F. Seyer, under whose d i r e c t i o n t h i s work was c a r r i e d out. CONTENTS In t r o d u c t i o n 1 M a t e r i a l s used ( Synthesis '2 P u r i f i c a t i o n 2 Standard of P u r i t y . . . . . 2 Experimental Procedure Constant Temperature Bath 4 Bath L i q u i d s 6 De n s i t y Determinations • 8 Surface Tension Determinations 10 V i s c o s i t y Determinations 13 Re s u l t s and General D i s c u s s i o n D e n s i t y R e s u l t s . 16 Temperature C o e f f i c i e n t s of Density 20 Surface Tension R e s u l t s 21 The Parachors 26 V i s c o s i t y R e s u l t s 27 Nissan's Viscosity-Temperature Equations . . . 30 V i s c o s i t y - S u r f a c e Tension R e l a t i o n s h i p s . . . . 32 Other R e l a t i o n s h i p s 37 Summary 39 B i b l i o g r a p h y 41 Appendix: Recommendations f o r Future Work . . . . . 43 PHYSICAL CONSTANTS OF SOME LONG-CHAIN NORMAL PARAFFIN HYDROCARBONS. INTRODUCTION The object of t h i s research was to i n v e s t i g a t e the d e n s i t y , surface tension, and v i s c o s i t y of some long-chain n - p a r a f f i n hydrocarbons over as great a l i q u i d range as p o s s i b l e ; and t o attempt to f i n d r e l a t i o n s h i p s between the p h y s i c a l constants h o l d i n g f o r lar g e p a r t s of the hom-ologous s e r i e s or ju s t f o r i n d i v i d u a l members of the s e r i e s . To f i n d r e l a t i o n s h i p s h o l d i n g f o r p a r t s of an homologous s e r i e s , i t i s o b v i o u s l y d e s i r a b l e t o measure the p h y s i c a l constants of as many of i t s members as p o s s i b l e . Time permitted the i n v e s t i g a t i o n of o n l y three hydrocarbons, however, so the r e s u l t s found could only be compared to known r e l a t i o n s h i p s e x i s t i n g f o r the lower members of the s e r i e s . The three hydrocarbons i n v e s t i g a t e d were Hexacosane ^Q«^Hcii)i Tetraeosane (C H ), and Octadecane ( C _ 0 H _ 0 ) . • 26 04 24 50 1 8 Density and surface tension measurements were taken f o r a l l three, but v i s c o s i t y measurements were taken f o r only the f i r s t and the l a s t , because of an i n s u f f i c i e n t supply of pure tetraeosane* - 2 ~ Apparatus f o r the measurements was set up; and various methods were t e s t e d and t h e i r l i m i t a t i o n s were de-termined. Work i n t h i s l a b o r a t o r y can thus proceed on these measurements f o r f u r t h e r members of the s e r i e s with a m i n i -mum o f experimentation. MATERIALS USED Synt h e s i s : M a t e r i a l s used were prepared and p u r i f i e d i n t h i s l a b o r a t o r y . Octadecane was synthesized by the Peterson 1 e l e c t r o l y t i c method from Eastman Kodak Company caprio a c i d . ' 2 Tetracosane was. synthesized by the S o r a b j i m o d i f i c a t i o n of the K r a f f t method from Kodak l a u r y l a l c o h o l . Hexacosane was synthesized by the Peterson e l e c t r o l y t i c method from Kodak 3 m y r i s t i c a c i d . P u r i f i c a t i o n : Tetracosane and hexacosane were both t r e a t e d w i t h small q u a n t i t i e s of concentrated s u l u h u r i e a c i d , f o l l o w -4 i n g the method o f P i p e r , et a l . A l l three were f i n a l l y p u r i f i e d by repeated r e c r y s t a l l i z a t i o n from d i s t i l l e d a c e t i e 3 a c i d u n t i l the samples gave constant m e l t i n g p o i n t s . Standard of P u r i t y : Samples were considered of s u f f i c i e n t p u r i t y i f o t h e i r melting p o i n t s and s e t t i n g points were w i t h i n 0 . 1 of the accepted v a l u e s . Determinations were made by the s t a n -1 dard method: a s m a l l sample being h e l d i n a f i n e c a p i l l a r y next to a thermometer bulb, and the two being immersed i n con-centrated s u l p h u r i c a c i d i n a long-necked f l a s k . M e l t i n g p o i n t s and s e t t i n g p o i n t s used were those observed by Seyer, 5 et a l , whose r e s u l t s checked c l o s e l y with those of P i p e r , 4 6 et a l , and Hildebrand and Waehter. There was some doubt about the exact p u r i t y o f the samples used, since they had a l l been stored i n g l a s s -stoppered b o t t l e s f o r a t l e a s t three years s i n c e t h e i r p u r i -f i c a t i o n . There may have been some change to isomers of s i m i l a r melting points to those of the normal p a r a f f i n s . This seems p o s s i b l e i n that the d e n s i t i e s determined near the m e l t i n g p o i n t s were a l l s l i g h t l y higher than those that 3 had been determined by Keays when the samples had been 7 f r e s h l y p u r i f i e d . Seansley and Carle ton , i n c r i t i c a l l y ex-amining d e n s i t i e s of the normal p a r a f f i n s up to hexadecane, found that contaminants are i n almost every case of h i g h e r d e n s i t y , and that lower d e n s i t i e s are i n h e r e n t l y more pro-bable. The values f o r the p h y s i c a l constants found may thus not be absolute values; but they w i l l be c l o s e a p p r o x i -mations to the absolute v a l u e s . In any event, t h e i r tempera-ture, c o e f f i c i e n t s should be almost i d e n t i c a l w i t h the tem-perature c o e f f i c i e n t s o f samples of the highest p u r i t y ; and the v a r i o u s p h y s i c a l constants w i l l be r e l a t e d to each other i n a normal manner f o r the s e r i e s . -4-EXPSRIMEHTAL PROCEDURE Constant Temperature Bath: The equipment f o r measuring the d e n s i t y , s u r f a c e tension, and v i s c o s i t y was a l l immersed i n the same constant temperature hath* Readings of a l l three were taken at the same temperature each time; and i n one run the three constants were found over the complete range f o r a sample* Readings were taken e x a c t l y at each 10 degrees, i n s t e a d of at odd temperatures, f o r ease of h a n d l i n g the r e s u l t s * The hath wasf a c y l i n d r i c a l pyrex j a r of 11 l i t r e s c a p a c i t y . (20 cm diameter and 45 cm deep) (See Figures I , I I , I I I , and I V ) . I t was h e a v i l y lagged w i t h asbestos and f e l t , and eneiosed i n a metal p a i l . The p a l l was fastened f i r m l y , to a bench; but, i n order to cut v i b r a t i o n to a minimum, the j a r was allowed to r e s t on a t h i c k f e l t pad w i t h i n i t . The bath had a heavy wood-and-asbestos-board cover which f i t t e d t i g h t l y , and from which a l l the apparatus w i t h i n the bath, except the s t i r r e r s , was suspended. This, again, was an e f f o r t to reduce any e x t e r n a l v i b r a t i o n s . Small windows were cut i n the l a g g i n g to view, the apparatus and to admit l i g h t * Care was taken to see that the g l a s s was f l a w l e s s at the windows. The bath was heated by one 500-watt and two 250-watt Cenco immersion heaters d i s t r i b u t e d through the bath* The l a r g e heater was connected through s e v e r a l v a r i a b l e r e s i s -tances to a single-tube Ceneo-DeEhotinsky mercury thermo-PLAN OF CONSTANT TEMPERATURE BATH Scale: approx. half sfze B - upn'ohf brass rods Surf.-ten. W<nd< Viscosity Window G^piHah meter atfached to brass upriaht by device •for- tilting it .-fro** Hie outside.-Density onfl Thermontfer H/inefo*/ Viscometer i*iHi cfamp on brass upright. Heafers thermometer ihern\ofeguhtort and brass uprights he/d by asbestos-wood cover fitY&d on pyrex jar. FiGuae I S t i r r i n g Motor Switchboard 'Constant Bath Temperature L i q u i d Bath Pump General View of Equipment F I G U R E I I Close-up view of Constant Temperature Bath L FIGURE I I I LA YOUT OF £ Wl TCHBOARD FI60RE ISO r e g u l a t o r w i t h a p r e c i s i o n c o n t r o l of 0,01 degrees from room o temperature to approximately 150 C. I t was found t h a t above o 150 Qf thermoregulators d i d not f u n c t i o n w e l l , and manual c o n t r o l of the r e s i s t a n c e s was more s a t i s f a c t o r y . The thermo-r e g u l a t o r was used w i t h an Aminco Su p e r s e n s i t i v e Mercury Belay. A l l e l e c t r i c a l apparatus was c o n t r o l l e d from a s i n g l e switchboard w e l l removed from the bath. (See Figure I I ) . The bath was equipped w i t h two s t i r r e r s , each w i t h three u p l i f t p r o p e l l e r s . For use on long runs, one s t i r r e r was run by a £-hp motor fastened to a nearby w a l l . The other s t i r r e r was operated by a s m a l l , smooth-running, l a b o r a t o r y motor, and was used f o r minimum v i b r a t i o n when t a k i n g readings. The bath was l i g h t e d by long, low-wattage l i g h t s s h i n i n g through a s l o t up i t s complete h e i g h t . I n t h i s manner i t was evenly l i g h t e d throughout w i t h a minimum i n f l u e n c e on the heat e q u i l i b r i u m w i t h i n the bath. Temperatures were measured by a s e r i e s of mercury thermometers graduated i n tenths of a degree. A l l thermo-meters were used completely immersed, and were p r e v i o u s l y c a l i b r a t e d a g a i n s t a Leeds and l o r t h r u p Platinum Resistance Thermometer tes t e d by the Bureau of Standards. Temperatures o were accurate to w i t h i n 0.1 degree i n the range from 20 C to 200°C, and were accurate to w i t h i n approximately 0.2 degree o o from 200 C t o 280 C. The bath was t e s t e d f o r temperature s t r a t a or other temperature d i f f e r e n c e s by means of a Beckmann -6-D i f f e r e n t i a l Thermometer, At 50°G i t d i d not vary more than z O . O l 0 at any p o i n t , and the r e g u l a t o r h e l d the temperature to w i t h i n ±0.05° over a p e r i o d of time. At 100°C and 150°C i t d i d not vary more than+ 0.03° at any p o i n t , and the regu-l a t o r h e l d the temperature to wi t h i n - i . 0 . 1 0 . This showed that the hath l i q u i d , the s t i r r i n g , and the temperature regu-l a t i o n were s a t i s f a c t o r y . A d e t a i l e d sketch with photographs o f the hath and a n c i l l a r y apparatus i s given i n Figures I , I I , I I I , and 17* Bath L i q u i d : The choiee of a s u i t a b l e hath l i q u i d was d i f f i c u l t ; and the c h a r a c t e r i s t i c s of the various hath l i q u i d s proved to he the l i m i t i n g f a c t o r s , determining the temperature range over which measurements could he a c c u r a t e l y taken. The f i n a l choice was Stanolax (a medium petroleum o i l made by Imperi a l O i l Company) f o r tne range up t o 60°C, and high-rmelting (128°-132°F) p a r a f f i n wax i n the range 60°C to 280°C. Readings o could not be taken above 280 0, A mere s u i t a b l e choice i n the range up to 90°G * would have been water, since i t s thermal c o n d u c t i v i t y i s 3£ times that of the petroleum o i l s , and i t s s p e c i f i c heat i s at l e a s t twice that of o i l s or p a r a f f i n . Thus i t would make accurate temperature c o n t r o l much e a s i e r i n i t s range. I t was not used, however, sinoe i t was found impossible to com-p l e t e l y dry the bath when changing over from the lower range l i q u i d to the p a r a f f i n wax; and i t was found that the water -7-formed numerous small "bubbles through the paraffin at the higher temperatures. The disadvantages of paraffin wax as a high tem-perature bath l iquid are that i t rapidly chars and beeomes opaque above 250°C, and that i t flashes on hot spots, such as the immersion heaters or wires wound outside the glass, between 260°C and 280°C. To part ia l ly prevent the flashing, the bath was as t ightly closed as possible at the top by means of asbestos plugged into a l l cracks, and the bath was very slowly heated i n this range; but the flashing was im-o possible to prevent even in this way above 280 C Because the paraffin'wax charred when exposed over long periods to high temperatures, i t was necessary to change the l iquid several times during a run. To f a c i l i t a t e the change, a small gear pump driven by a i - h p motor was used to draw the hot l iquid quickly out of the bath through glass tubes and steel pipes. (See Figures III and IV). Fresh, preheated wax could then be poured in , and the previous tem-perature could be quickly attained once more. Numerous organic bath liquids are mentioned in the l i terature , and several were tested, but a l l have the same drawbacks as paraffin wax, and none was found to be superior to i t . Christensen and King mention a mixture of ortho-o and meta-phosphoric acid suitable up to 250 C. It was tried above 250°C, but was found to slowly turn to the meta state above 280°C. It has the advantage of high heat capacity and -8-no f i r e hazard; hut i t has the disadvantage that no metal or wooden f i x t u r e s oan he used i n i t . Various molten s a l t s were a l s o tested as hath l i q u i d s , hut a l l the s a l t s t e s t e d o were opaque around 300 0. Stanolax and p a r a f f i n wax were thus chosen as the-best compromises f o r bath l i q u i d s ; and the temperature of operation was l i m i t e d a c c o r d i n g l y . To overcome t h e i r poor heat t r a n s f e r and heat c a p a c i t y q u a l i t i e s i t was decided to use heavy i n s u l a t i o n on the bath. Slow heat l o s s was a l s o obtained by balancing the heat input and outflow f a i r l y c l o s e l y , and using a minimum of r e g u l a t i o n . D e n s i t y Determinations: D e n s i t i e s were determined by the d i l a t o m e t r i c method. The dila t o m e t e r s used consisted of 1-mm c a p i l l a r y about 35 cm l o n g . A bulb about 1.5 cc i n volume was blown onto one end. A l a r g e r bulb was then blown onto the top end to aid i n f i l l i n g . A s m a l l mark was etched near the l o v e r end f o r reference. A sketch o f the di l a t o m e t e r used i s given i n Figure V. Three such dilatometers were r e q u i r e d to cover the temperature range i n v e s t i g a t e d . A l l c a p i l l a r i e s used were c a r e f u l l y s e l e c t e d pyrex tubing examined f o r constant c r o s s - s e c t i o n throughout t h e i r l e n g t h . They were examined by i n t r o d u c i n g a s m a l l column of mercury and measuring i t s l e n g t h at centimeter i n t e r v a l s along the tube by means of a Cenco Measuring M i c r o -scope reading to 0.001 cm. A thermometer clamped to the tube was read at i n t e r v a l s to check on constant temperature. Th/cfc-wa/fee/ tubing for ttfacAinp to vacuum Large bulb o#se/for-ease of f///ny DESIGN or DILATOMETER FIGURE X Carefully se/ecfed f-/n/7i Pyr-ex Cap'lfar-y -fu6*'^y 3S~ crn /ony Etch mark Bulb blown about /.Sec. -9-The completed d i l a t o m e t e r was c a l i b r a t e d by d i s -t i l l i n g p u r i f i e d mercury i n t o i t under vacuum, weighing the mercury added, and measuring i t s p o s i t i o n with regards to the etched reference mark. The p o s i t i o n was measured f o r s e v e r a l d i f f e r e n t temperatures.' I t was then a simple matter to c a l -c u l a t e the volume of the b u l b and the c r o s s - s e c t i o n a l area o f the c a p i l l a r y , s i n c e the s p e c i f i c volume of mercury and i t s temperature c o e f f i c i e n t of expansion are a c c u r a t e l y known. Meniscus c o r r e c t i o n s and c o r r e c t i o n s f o r expansion of the glass were i n c l u d e d i n t h i s and a l l subsequent c a l c u l a t i o n s . A d i l a t o m e t e r was f i l l e d w i t h a p a r a f f i n sample by p l a c i n g the sample i n the upper bulb i n the s o l i d s t a t e . A h i g h vacuum was then a p p l i e d , and the sample was r e p e a t e d l y melted and s o l i d i f i e d u n t i l no d i s s o l v e d gases remained. The whole d i l a t o m e t e r was then heated, and the sample was allowed to run down to the lower bulb. With p r a c t i c e , l i t t l e a d j u s t -ment of volume was then necessary. I f there was an excess, however, i t was removed by heating the d i l a t o m e t e r i n a small bath (a very long-necked f l a s k ) t o the highest temperature to be a t t a i n e d w i t h that sample, then catching the excess i n the upper bulb. Any p a r a f f i n l e f t i n the c a p i l l a r y or upper bulb a f t e r the volume was adjusted was taken out by heating under vacuum and d i s t i l l i n g i t o f f . -10-The d i l a t o m e t e r was weighed before and a f t e r f i l l i n g . I t was attached to the vacuum system by rubber tubing i n order not to a f f e c t the weight of the g l a s s . Heating was done w i t h an e l e c t r i c heater f o r the same reason. Weighing the long tube was f a i r l y d i f f i c u l t , as i t c o u l d onl y be l a i d f l a t across the s c a l e pan. Weighing was done on a chainomatic balance w i t h accurate weights c a l i b r a t e d to 0.0001 grams. Weighings were repeated u n t i l constant. When f u l l , the d i l a t o m e t e r was f i r m l y elamped to an upright brass r o d i n the c e n t e r of the bath. (See Figure I ) . Headings of meniscus height above the etched mark were taken w i t h a Wm. Gaertner and Co. eathetometer reading to 0.005 em. Surface Tension Determinations: Surface tensions were determined by the d i f f e r e n -9 t i a l c a p i l l a r y r i s e method described by S. Sugden and by 10 Rich a r d s , et a l . The c a p i l l a r i m e t e r c o n sisted of two d i f f e r e n t -s i z e d c a p i l l a r i e s ' joined at the bottom and open to the l i q u i d at the bottom, a l l encased i n a t h i n - w a l l e d tube j u s t l a r g e enough t o take the U-shaped c a p i l l a r i e s . A sketch of the c a p i l l a r i m e t e r used i s given i n Figure V l . DES/GN OE CAP/L L ARI METER ThicJc-trVa/Zed tuS/hy for a/fac/i//iy To tfacuurn JLctiyer Cap/'ffary ( 0 2 2 0 cm <f>) Finer Capil/ary (o07Qo*t4>) Fnve/opirty t~u6e, fes/ed for oph'ca/ defecfs St*/ o/fher^^ NOT£~: Mel/tod o f Siiyden •far ho/diny Capillaries /n -/"he. Hsbe is/as fauna" l~o Se./ otp s/nzSris, and was difficult /-o clean ; b u t // is Me besr way 7*b join the capillaries "lb Hie enve/opt'ny tube. f* s shown . -11-The c a p i l l a r i e s used had Inside diameters of o 0.220 cm and 0.070 cm at 20 C. lubes w i t h Inside diameters of 0.152 cm and 0.020 cm were tested a l s o . They gave l a r g e r d i f f e r e n t i a l r e a d i n g s ; but the f i n e c a p i l l a r y was too f i n e to reach an e q u i l i b r i u m reasonably q u i c k l y because of extreme-l y slow drainage. The c a p i l l a r i e s were c a r e f u l l y s e l e c t e d pyrex tubing examined i n the same manner as t h a t described f o r the d i l a t o m e t e r c a p i l l a r i e s . The enveloping tube was 22-mm t h i n - w a l l pyrex, e a r e f u l l y examined f o r any o p t i c a l d e f e c t s by measuring an object i n s i d e i t from d i f f e r e n t angles by means of a cathetometer. The tubes were c a l i b r a t e d w i t h pure benzene and wi t h c o n d u c t i v i t y water. Before c a l i b r a t i o n , the tubes were c a r e f u l l y cleaned, washed at l e a s t 20 times w i t h c o n d u c t i v i t y water, then d r i e d under vacuum. Pure benzene was then d i s t i l l e d from sodium d i r e c t l y i n t o the tube under vacuum, and the tube was sealed w i t h the vacuum s t i l l on. In the case of the water, i t was put i n the tube a f t e r washing, then sealed under vacuum. The water d i d not stand i n the tubes i n the same reg i o n as the p a r a f f i n s and the benzene d i d , but i t gave a very n i c e check on the c a l i b r a t i o n and the u n i f o r m i t y of the c a p i l l a r i e s . The pure benzene was prepared i n the f o l l o w i n g manner: 500 ce of Baker?s OF Analyzed Benzene (benzo l -thiophene f r e e ) were c r y s t a l l i z e d i n an i c e bath u n t i l a l l but 50 cc were c r y s t a l l i z e d . This residue was discarded. A f t e r f o u r such c r y s t a l l i z a t i o n s a constant f r e e z i n g point o of 5.46 0 was obtained, as measured by a Leeds and Nor thru p Platinum Hesistance Thermometer. The benzene was then kept over sodium i n a stoppered b o t t l e , and used as soon as p o s s i b l e afterwards. The c o n d u c t i v i t y water was prepared i n the s t a n -dard manner. C a r e f u l l y d i s t i l l e d water was allowed to stand f o r a p e r i o d w i t h a l i t t l e KMnO^, a f t e r which i t was again d i s t i l l e d i n an a l l - g l a s s , thoroughly-steamed, Pyrex appa-ratus w i t h ground-glass j o i n t s . For c a l i b r a t i o n purposes a middle f r a c t i o n was used immediately a f t e r d i s t i l l a t i o n . The remaining water prepared i n t h i s way was used f o r washing apparatus. D e n s i t i e s and surface tensions used f o r water and benzene were those given by Richards, et al 1®. The l i n e a r c o e f f i c i e n t of expansion of pyrex g l a s s , 0.32 x 10 , was a p p l i e d to the c a l i b r a t i o n . A l l samples of the p a r a f f i n s were f i l t e r e d f o r dust, and were loaded by means of long funnels. They were sealed i n the c a p i l l a r i m e t e r under vacuum, hence the s u r -face tensions measured were those under the substance's own vapour pressure. -13-D i f f e r e n t i a l height measurements were taken by means of a P r e c i s i o n Tool and Instrument Co. cathetometer reading to 0.001 cm.-V i s c o s i t y Determinations: V i s c o s i t i e s were determined by means of XT-tube viscometers made according to the requirements of the B r i t i s h Standards I n s t i t u t e Standard l o . 188-1937, " B r i t i s h s t a n -dard method f o r the determination of v i s c o s i t y of l i q u i d s i n absolute (C.&.S.) u n i t s " . Three s i z e s of these v i s c o -meters were used, w i t h e a p i l l a r y bores 0.038 cm I.D. f o r the range 0.5 - 1.5 cs, 0.060 cm I.D. f o r the range 1.5 -5.0 cs, and 0.115 cm I.D. f o r the range 5o.O - 7.0 cs. The tubes were f i t t e d w i t h the s p e c i f i e d brass clamps, and were f i r m l y held i n the bath by a clamp a l l o w i n g adjustment f o r the v e r t i c a l . F i t t i n g s were made f o r the tops of the viscometers t o prevent contamination, y e t to f a c i l i t a t e drawing t h e , l i q u i d into the hi g h e r r e s e r v o i r and r e l e a s i n g i t q u i c k l y . The s u c t i o n was attached t o an or d i n a r y water suction pump to allow c a r e f u l adjustment of the s u c t i o n speed. For higher temperatures, the f i t t i n g was ground onto the viscometer. For lower temperatures i t was found more convenient to use rubber connections, and take the excess weight from the top of the viscometer. Bath temperature was c o n t r o l l e d as s p e c i f i e d i n the above standard (see s e c t i o n on Constant Temperature B a t h ) ; and the c a l i b r a t i o n s and observations were c a r r i e d out as -14-s p e e i f i e d . The two f i n e r tubes were c a l i b r a t e d w i t h con-d u c t i v i t y water, prepared as p r e v i o u s l y described. They l a t e r checked w e l l against each other u s i n g the p a r a f f i n s . The l a r g e r tube was c a l i b r a t e d against them u s i n g the para-f f i n s . A.S.T.M. recommended v i s c o s i t i e s f o r water were used • i n the c a l i b r a t i o n . The B r i t i s h Standard viscometer i s w e l l designed .11 and has been proved by S t e i n e r to g i v e accurate r e s u l t s i f c a r e f u l l y handled. I t s check on the l o a d i n g e r r o r i s u s e f u l f o r work over l a r g e temperature ranges, i t each temperature the f i l l was adjusted e a s i l y by means of a long f i n e tube w i t h an eye-dropper bulb at one end. The viscometer was never moved during a run. The o n l y e r r o r t h a t needed watching was the K i n e t i c 12 Energy e r r o r . Cannon and Fenske , i n d i s c u s s i n g v i s c o s i t y measurement e r r o r s , point out that the c o r r e c t i o n f o r the E.E. e r r o r should be kept below 0.2%, as i t i s o n l y accurate to about 20%. The f i n a l e r r o r i s then o n l y 0.04%. Even w i t h i n the s p e c i f i e d ranges, however, the Z.E. e r r o r i n a B r i t i s h Standard viscometer may be as h i g h as 0.5%, which may give a r e s u l t a n t e r r o r of 0.1%. This can be kept down only by changing sooner than recommended to a s m a l l e r - s i z e d viscometer. There was no e r r o r caused by the a b s o r p t i o n of r a d i a n t heat i n these determinations because p a r a f f i n s were -15-being examined, and the bath l i q u i d c o n s i s t e d of s i m i l a r l y -coloured p a r a f f i n wax. I f other bath l i q u i d s were used, t h i s e r r o r could become important a t the h i g h e r temperatures. The deciding e r r o r i n these determinations was i n the t i m i n g . The e f f l u x time was measured by means of a Mey-l a n stopwatch graduated i n 1/5 seconds and checked agai n s t 11 r e l i a b l e timepieces. S t e i n e r has shown by c a r e f u l work that stopwatches are, as a r u l e , not s u f f i c i e n t l y p r e c i s e f o r the p r e c i s i o n measurement of v i s c o s i t y . Above 100 seconds (the range used here) the e r r o r i s probably w i t h i n 0.2%, This e r r o r i s d i r e c t l y r e f l e c t e d i n the c a l c u l a t e d v i s c o s i t y , however, and s i n c e i t i s the l a r g e s t s i n g l e e r r o r i n the determination i t should be reduced i n f u t u r e . I t can o n l y be reduced by the use of some s o r t of e l e c t r o n i c p r e c i s i o n timer accurate to 0.01 seconds, such as described. 13 14 15 by P r y and B a l d e s c h w i e l e r , Pen the r and Pompeo , or S t e i n e r . W ith an e l e c t r o n i c timer the l i m i t i n g e r r o r i s 16 the o p t i c a l r e a c t i o n time o f the observer, which Speakman po i n t s out cannot be reduced by p r a c t i c e to l e s s than 0.160 seconds. Since the same e r r o r i s present i n stopping and s t a r t i n g , however, there i s compensation f o r t o t a l time elapsed; and since the i n s t a n t of the passing of the meniscus i s a n t i c i p a t e d , i t i s reasonable t o time to 0.01 seconds. -16-RESULTS AND GENERAL DISCUSSION Density R e s u l t s : Results obtained I n the d e n s i t y determinations are given i n d e t a i l i n Tables I , I I , and I I I . The general equations f o r temperature c o e f f i c i e n t of d e n s i t y were c a l -c u l a t e d i n the ranges i n which the samples were known not to have charred. The equations were c a l c u l a t e d by the method of l e a s t squares, a f t e r assuming the f i r s t constant i n each case f o r s i m p l i f i c a t i o n . The number o f terms necessary i n the power s e r i e s was determined by the method of f i n i t e d i f f e r e n c e s , and was found i n each case t o be three terms 2 (up t o c ( t - t Q ) ). The ac c u r a c i e s of the readings were estimated to be as given f o r the equations. The c o e f f i c i e n t s of expansion are given are simply u s e f u l approximations i n the lower tem-perature ranges. D e n s i t i e s were determined f o r both r i s i n g tem-perature and lowering temperature and both checked c l o s e r than the accuracy given. There was no apparent h y s t e r e s i s i n any sample. The d e n s i t y curves are shown i n Fi g u r e V I I . As would be expected, they are roughly p a r a l l e l w i t h s l i g h t o curvature. Above 200 C the curves are not as regular as below. This i s p a r t l y due to the f a c t that the samples charred s l i g h t l y over a p e r i o d of time above 200°C, and -17-TaBLE I Density of Ootadeeane (Ci8 H38^ General equation calculated over range 30°C to 250°' d t = 0,7833 - 0.674(10"^) ft-30) - 0.075(lO"^ ( tSofl l o " 4 ^ 5 in range m.p, - 200° where A - 8 in range 200° - 250° 10 i n range 250° - 280° t°C Spec Vol (obs) Density - d fobs) d fcalc) Diff A (xl6-4) d Kraf ft d others 28.1 .7846 Dover 19 30 1.2765 .7834 .7833 -1 .77 57 .7790(32°) 40 1.2877 .7766 .7766 0 .7688 50 1.2990 .7698 .7698 0 .7618 .7756(42°) 60 1.3106 .7630 .7630 0 .7550 70 1.3226 .7561 .7502 •*! .7482 80 1.3346 .7493 .7494 ••1 .7416 90 1.3464 .7427 .7426 -1 .7349 100 1.3589 .7359 .7357 -2 . .7284 110 1.3717 .7290 .7289 - a 120 1.3850 .7220 .7220 0 130 1.3982 .7152 .7152 0 140 1.4120 .7082 .7083 + 1 150 1.4257 .7014 .7013 -1 160 1.439 7 .6946 .6944 -2 170 1.4541 .6877 .6875 -2 180 1.4686 .6809 .6805 -4 190 . 1.4839 .6739 .6736 -3 200 1.4997 .6668 .6665 -3: 210 1.5163 .6595 .6595 + 1 220 1.5335 .6521 .6525 + 4 230 1.5501 .6451 .6455 + 4 240 1.5669 .6382 .6385 -f3 250 1.5848 ,6310 .6314 f4 260 1.6028 .6239 .6243 +4 270 1.6205 .6171 .6170 -1 280 1.6391 .6101 .6101 0 Coeff. of Expansion = approx. 0.0115 co/deg/co (range- m.p. to 100°) -18-TABIE I I Density of Tetracosane 1 f C £ 4 H 5 0 ) General equation c a l c u l a t e d over range 60°C to 250°C d t r 0.7749 - 0.646(10-J) f t - 60), - 0.10(10"*) f t - 6of*10~*d inhere A * 5 i n range m.p. - 200° 8 i n range 200° - 250° 10 i n range 250° - 280° t°C Spec Y o l v • l / d (obs) Densi t y d fobs) d f c a l c ) D i f f (xlOT 4) d 3 Keays d others 50.7 .7809 - .7772 Richter2° 60 1.2906 .7748 .7749 -Kl .7713 .791f5i°J 70 1.3012 .7685 .7684 -1 .7651 McEittadck^ 80 1.3125 .7619 .7620 <tl . 7682f70°) 90 1.3238 .7554 .7554 0 22 100 1.3354 .7488 .7489 -fl voxi nuun .764(76°) 110 1.3471 .7423 .7424 +1 Eggloff. 120 1.3594 .7356 .7357 +1 .7628(76°) 130 1.3717 .7290 .7292 42 140 1.3844 .7223 .7226 f-3 150 1.3970 .7158 .7160 42 160 1.4098 .7093 .7093 0 170 1.4226 .7029 .7026 -3 180 1.4363 .6962 .6960 -2 190 1.4505 .6894 .6892 -2 200 1.4649 .6826 .6825 -1 210 1.4792 .6760 .6758 -2 220 1.4940 .6693 .6689 ^4 230 1.5094 .6625 .6622 -3 240 1.5250 .6557 .6554 -3 250 1.5417 .6486 . .6486 0 260 1.5583 .6417 .6417 0 270 1.5755 .6347 .6348 . +1 280 1.5936 .6275 .6276 +1 Coeff. of Expansion = approx. 0.0112 ec/deg/cc (range - m.p. to 100°) TABLE I I I De n s i t y of Hexacosane (CggH^) General equation c a l c u l a t e d over range 60°C to 250°C d t s 0.7788 - 0.640(10'J) ( t - 60) - 0.15(10"6) ( t - 60f"t lo"*4 where 4 s 5 i n range m.p. - 200° 10 i n range 200° - 250° 15 i n r a i ^ e 250° - 280° t ° c Spec v o l v « i / d fobs) D e n s i t y d fobs) d (oalc ) D i f f (xlCT4) d 3 Keays a others 55.8 60 70 80 90 100 1.2840 1.2947 1.3057 1.3170 1.3282 .7788 .7724 .7659 .7593 .7529 .7815 .7788 .7724 .7659 .7595 .7529 0 0 0 42 0 .7796 .7768 .7707 .7642 .7565 Schmidt .7780(70°) .7691(89°) B u e k l e r 2 5 n .7580(84°) 110 120 130 140 150 1.3399 1.3517 1.3639 1.3763 1.3888 .7463 .7398 .7332 .7266 .7200 .7464 .7399 ..7333 .7266 .7200 +1 +1 +1 0 0 160 170 180 190 200 1.4013 1.4144 1.4277 1.4411 1.4575 .7136 .7070 .7004 .6939 .6861 .7133 .7066 .699 8 .6931 .6863 -3 -4 -6 -8 t2 210 220 230 240 250 1.4718 1.4869 1.5030 1.5186 1.5356 .6794 .6725 .6653 .6585 .6512 .6796 .6726 .6657 .6587 .6518 +2 +1 44 +2 +6 260 270 280 1.552 3 1.5698 1.5875 .6442 .6370 .6299 .6448 .63 7 8 .6307 +6 +8 *8 Coeff. of Expansion - approx. 0.0111 cc/deg/cc (range t m.p. to 100°) FIGURE YH -20-p a r t l y to the f a c t that i n t h i s range i t i s . v i r t u a l l y im-p o s s i b l e to prevent c a s u a l movements of the meniscus while taking r e a d i n g s . At t h i s point a t t e n t i o n should again he drawn to the remarks i n the s e c t i o n on M a t e r i a l s Used regarding the p u r i t y of the samples used and the accuracy of the d e n s i t i e s determined. Temperature C o e f f i c i e n t s of Density: 17 C a l i n g a e r t , et a l t c o l l e c t e d s e l e c t e d , smooth values of the temperature c o e f f i c i e n t s of d e n s i t y f o r the lower p a r a f f i n hydrocarbons to G ^ g H g g and found the e m p i r i c a l r e l a t i o n : d t = So"*" a ( t " 2 0 * * f l J / 2 , f t - 2 0 , 2 where a s temp, eo e f f . of d s - 0.0298 t 0.00788N 2.0162+14. 0262ET b s temp, c o e f f . of a, and l o g ( - b ) s -5.3 -0.1H They suggested t h i s r e l a t i o n could be e x t r a p o l a t e d at l e a s t as high as Ggg H4 6» I f w e e x t r a p o l a t e i t , assuming i t holds e q u a l l y w e l l f o r the r e l a t i o n : d t = d s •* *(* - *B> + (o / 2 ) ( t - t B ) 8 where t g i s any reasonable temperature, as clo s e to 20°C as p o s s i b l e , we can then compare i t to the values found e x p e r i m e n t a l l y as f o l l o w s i n Table 17. -21-TABLE IV C18 H38 C24 H50 G 2 6 H 5 4 x l O J ±10* d30 x l 0 J x l O 6 -a x l O 7 x l O * observed Calingaert K r a f f t 1 8 0.674 0.674 0.7024 0.075 0.08 -0.395 0.7833 0.7764 0.7757 0.646 0.646 0.10 0.02 0.640 0,640 0.15 0.013 Surface Tension R e s u l t s ; R e s u l t s obtained In the s u r f a c e t e n s i o n determina-t i o n s are g i v e n i n d e t a i l i n Tables V, VI, and V I I . A graph of the r e s u l t s i s shown i n Figure V I I I . Molar s u r f a c e energy was taken as ) ( ( M v ) 2 ^ ergs per sq cm, and the Eotvos constant as - dCV(Mv) g / g J . dT A graph of the molar surface energy against tem-perature (See Figure IX) gives a reasonably s t r a i g h t l i n e over the e n t i r e temperature range measured. I t should be noted here that c h a r r i n g d i d not a f f e c t the surface t e n s i o n r e s u l t s as much as i t d i d the d e n s i t y and v i s c o s i t y r e s u l t s at h i g h temperatures because the l i q u i d s were sealed i n the c a p i l l a r i m e t e r under h i g h vacuum. General equations are given f o r each p a r a f f i n i n the form suggested by Ramsay and S h i e l d s : *(M¥) 2/ 3 = E ( t c - t - <£) -22-TABLE Y Surfaoe Energy of Ootadeoane ( C 1 8 H 3 8 ) General equation In the form o f Ramsay and S h i e l d s : XTMV) J - s . o i . f t 0 - t -4 ) where V * Surface t e n s i o n M » Molecular weight * 254.48 t e - C r i t i c a l temperature » 490.5 ( W i l s o n 2 6 ) - 25 (obtained by g r a p h i c a l means) t° c v - l / d (obs) dyn/cm (obs) ' o ther) Molar surface energy j f M v % Eotvos c oust Ramsay S h i e l d s const. Parachor 0] 30 40 50 1.2765 1.2877 1.2990 28.71 27.70 26.80 Dover 27.58 (32°) 1357 1317 1281 3.8 3.11 3.09 3.08 754 751 753 60 70 80 90 100 1.3106 1.3226 1.3346 1.3464 1,3589 25.86 25.04 24.17 23.38 22.60 1244 1212 1177 1144 1113 3.3 3.07 3.06 3.05 3.05 3.05 753 754 754 754 754 110 120 130 140 150 1.3717 1.3850 1.39 82 1.4120 1,4257 21.84 21.06 20.31 19.70 19.00 1083 1051 1020 996 966 2.9 3.05 3.04-3.04 3.05 3.05 754 754 754 754 755 160 170 180 190 200 1.4397 1.4541 1.4686 1.4839 1.4997 18.18 17.48 16.70 16.01 15.45 931 901 866 836 814 2.9 3.04 3.04 3.03 3.03 3.06 758 7 57 755 755 758 210 220 230 240 250 1.5163 1.5335 1.5501 1.5669 1.5848 14. 76 14.2 6 13.49 12 .75 12.0 782 762 726 690 656 3.1 3.05 3.09 3.07 3.05 . 3.03 757 757 758 758 753 260 270 280 1.6028 1.6205 1.6391 11.4 10.9 10.3 627 604 1 575 2.6 3.04 3.08 3.09 753 752 750 averages - 3.06 755 Accuracy of Y - appro*, to.05 (30°-100°) + 0.08 (100°- 240°) tO,2 (240°-280°) -23-TABIE VI Surface Energy of Tetracosane (^g^gg) General equation i n the form of Bams ay and S h i e l d s : X(Mv)Vjr» 3. 4 4 ( t 0 - t - i ) where V = Surface t e n s i o n M = Molecular weight • 338.64 g r C r i t i c a l temperature * 561.5r.(Texas Co i> = 25 (obtained by g r a p h i c a l means) t°c v - l / d (obs) dyn/cm (obs) Molar surface energy Eotvos const. Bamsay S h i e l d s const. Parachor 0 0 60 1.2906 27.52 1585 3.33 1000 70 1.3012 26.85 1555 3.34 1003 80 1.3125 26.07 1518 3.33 1004 90 1.3238 25.45 1491 3.35 1006 100 1.3354 24.75 1458 3.2 3.34 1008 110 1.3471 23.90 1417 3.33 1008 120 1.3594 23.20 1383 3.33 1008 130 1.3717 22.38 1341 3.31 1007 140 1.3844 21.57 1301 3.29 1008 150 1.3970 20.83 1265 3.8 3.28 1008 160 1.4098 20.14 1230 3.27 1010 170 1.4226 19.42 1193 3.26 1012 180 1.4363 18.71 1157 3.25 1012 190 1.4505 17.87 1113 3.22' 1011 200 1.4649 17.21 1078 3.8 3.24 1011 210 1.4792 16.76 " 1057 3.24 1013 220 1.4940 16.13 1024 3.24 1013 230 1.5094 15.45 988 3.23 1013 240 1.5250 14.85 956 3.23 1013 250 1.5417 14.18 919 3.4 . 3.21 1013 260 1.5583 13. 5 882 3.20 1013 270 1.5755 13.0 855 3.21 1012 280 1.5936 12.4 822 3.0 3.21 1012 t Averages - 3.27 1009 # TSo previous record of X f o r C 2 4H5o found i n the l i t e r a t u r e . Accuracy o f )f - approx-t0.05 (60°-100°) £ 0.08 (100°- 250? i-0.2 (250° - 280°) -24-TABLE V I I Stir face Energy o f Hexacosane f°26H54^ General equation i n . the form o f Ramsay and S h i e l d s : o'fMv)^: 3 . 4 9 ( t c - t ~i ) where % = Surface t e n s i o n M » Molecular weight • 366.69 2 t G= C r i t i c a l temperature - 583.0 (Texas Co. £ s 25 (obtained by g r a p h i c a l means) t°c V=l/d (obs) dyn/cm (obs) V (others) Molar s u r f a c e Eotvos c oris t . Ramsay S h i e l d s const. Parachoi 60 1.2840 27.8 1682 3.38 1081 70 1.2947 27.2 1650 3.39 1082 80 1.3057 26.4 1615 3.38 1084 90 1.3170 25.6 1576 3.37 1086 100 1.3282 24.9 1451 3.5 3.37 1087 110 1.3399 24.4 Schenck 1517 3.38 1101 120 1.3517 23.6 24.79 n 1478 3.37 1092 130 1.3639 22.8 (115.4°) 1438 3.36 1089 140 1.3763 22.0 1395 3.34 1092 150 1.3888 21.3 1359 3.9 3.33 1093 160 1.4013 20.6 1322 3.33 1094 170 1.4144 20.1 1297 3.34 1097 180 1.4277 19.4 1260 3.34 1098 190 1.4411 18.8 1228 3.34 1098 200 1.4575 18,2 1199 3.1 3.34 1102 210 1.4718 17.6 1167 3.35 1104 220 1.4869 17.1 1139 3.37 1111 230 1.5030 16.5 1109 3.38 1109 240 1.5186 15.8 1069 3.36 1110 250 1.5365 15.2 1036 3.3 3.36 1111 260 1.5523 14.6 1002 3.36 1117 270 1.5698 14.0 966 3.36 1110 280 1.5875 13.5 937 3.3 3.37 1108 Averages - 3.36 1094 Accuracy o f $ - approx-tO.l (60° - 100°) 10.2 (100° - 200°) ±0.5 (200° - 280°) . Sur/ace Tension - Temperature Curves for-Hexacosane , Tefracosane . ancf Ocfactecane Soo to iz 14 '6 18 2o ZZ 24- 26 28 So Surface "Tension t dynes/cm FIGURE THE. Mo Jar Surface Energy - 7etnperctfure Curves for Hex a co sane, 7etracosa/ie, and Ocfac/e&me Soo Soo 7oo Soo 1100 Uoo tsioo Afo/or Surface £ner^y J e/ys/ff.cm. FIGURE l£ because i t f i t s the r e s u l t s so w e l l . The constant was obtained by p l o t t i n g the curve on l a r g e - s c a l e graph paper and e x t r a p o l a t i n g to zero molar surface energy. In a l l cases i t was found to be w i t h i n a few degrees of 25 below the c r i t i c a l temperature. Since i t i s not a c r i t i c a l f i g u r e , and s i n c e i t was d i f f i c u l t to determine e x a c t l y , i t was taken as 25 i n a l l three cases. This i s not a t a l l c l o s e to the f i g u r e of 6 found by Ramsay and S h i e l d s f o r many l i q u i d s , but i t f i t s the eases w e l l . The curve . a c t u a l l y f l a t t e n s out before i t reaches t h i s p o i n t , anyway, and becomes tangent to the temperature a x i s at the c r i t i c a l temperature. The constant "k^ was averaged from a l l r e a d ings. Walden discovered an e m p i r i c a l formula f o r k as f o l l o w s : k . 1.90 - COllinVA* where A i s the atomic weight and n i s the number of atoms of each element i n the molecule. The k's c a l c u l a t e d from t h i s formula are compared i n Table V I I I to the observed v a l u e s . TABLE V I I I C18 H38 °24 H50 °26 H54 k (Walden*s equation) 3.01 3.37 3.49 k (observed) 3.06 3.27 3.36 -26-For f i n e r r e s u l t s , tfCtiLv)2/3 should be rep l a c e d byVV M where d 1 i s the d e n s i t y of the vapour. °id-r-dj The vapour pressures f o r the p a r a f f i n s have not been mea-sured over a l l . t h i s range, however. Tapour d e n s i t i e s could be c a l c u l a t e d from the known vapour pressures up to 100°C, but they would be estimates, and since the c o r r e c t i o n i s small i t was not considered worth the time. The Paraehors; The Parachor [P[] i s the constant i n the equation: f p l s M V * L 1 T^dT where the d e n s i t y of the vapour ( d 1 ) may be ne-g l e c t e d i n comparison to t h a t of the l i q u i d . S. Sugden proposed Parachor e q u i v a l e n t s of Cs4.8 and H-17.1 w i t h a CHg increment of 39 i n an homologous se-r i e s . S. A , Mumford and J.W.C.Phillips proposed Parachor equivalents of 0=9.2 and B>15.4 w i t h a CH g increment o f 40 i n an homologous s e r i e s . Table IX compares these c a l c u -l a t e d Paraehors w i t h the observed Paraehors. TABLE IX Ca l c u l a ted Sugden C a l c u l a t e d M & P Observed Obs. bygo Schenck [*] °18 H38 736.2 750.8 755 ••• 1*1 G 2 4 H 5 0 970.2 990.8 1009 0] C26 H54 . 1048.2 1070.8 1094 1082 CHg Increment 39 40 42 -27-V i s c o s i t y R e s u l t s : R e s u l t s obtained i n the v i s c o s i t y determinations are g i v e n i n d e t a i l i n Tables X and X I . A grapb of the r e -s u l t s i s shown i n Figure X. To f i n d a s t r a i g h t - l i n e r e l a t i o n s h i p between the v i s c o s i t y and temperature, a p l o t was f i r s t made o f Andrade's simple equation: O » Ae~ D/^ (See Figure X I ) . As was to ' 30 be expected, according to Evans , t h i s gave a curve s l i g h t -l y convex to the l/T a x i s . Since i t s t r a i g h t e n e d the curves considerably, however, i t gave a good check on the v a l i d i t y of the readings. I t was i n t e r e s t i n g to note that i t markedly showed the e f f e c t of c h a r r i n g i n the hig h e r temperature range f o r Octadecane. M o d i f i c a t i o n s of various equations as described 30 x by Evans were then p l o t t e d . The equation g i v i n g the best 31 r e s u l t s i n a reasonable form was that of Walther as accepted by the A.S.T.M., and now c a l l e d the A.S.T.M. Equation. This i s an expected r e s u l t , s i n c e the equation has proved very s a t i s f a c t o r y f o r petroleum o i l s . The graph i s shown i n Figure X I I . General equations are ther e f o r e given f o r both the p a r a f f i n s tested i n the form of the A.S.T.M. Equation: l o g l o g (VT + *-) * AlogT-f B where ] ) r i s the kinematic v i s c o s i t y -28-TAB1E 2 V i s o o s i t y of Octadecane ^C^gHgg) General equation In the A.S.T.M. form: l o g l o g (V * 0.8) = -3.60 l o g T - 0.437 where \> i s the kinematic v i s c o s i t y i n c e n t i s t o k e s T i s the absolute temperature (Constants were obtained by method of s e l e c t e d p o i n t s ) t°C Density d Kinematic v i s e . y c s . Dynamic v i s e . Y) =V4cp. (o th ers) 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 0.7834 0.7766 0.7698 0.7630 0.7561 0.7493 0.7427 0.7359 0.7290 0.7220 0.7152 0.7082 0.7014 0.6946 0.6877 0.6809 0.6739 0.6668 0.6595 0.6521 0.6451 0.6382 0.6310 0.6239 0.6171 0.6101 5.079 4.073 3.325 2.806 2.371 2.050 1.807 1.573 1.414 1.272 1.140 1.034 0.946 0.88 0.82 0.76 0.70 0.65 0.61 0.57 0.54 0.49# 0.45# 0.41# 0.38# 0.34# 3.979 3.163 2.560 2.141 1.792 1.536 1.342 1.157 1.031 0.919 0.815 0.732 0.682 0.61 0.56 0.52 0.47 0.44 0.40 0.37 0.35 0.32 0.29# 0.26# 0.23# 0.21# Ubbelohde 3 2 2.86 (40°) 1.92 (60°) 1.34 (80°J 1.06 (100°) Dover „ 3.557 (32 ) 2.790 (42°) Accuracy - approx. -*0.005 i n range 30°* 150° o 10.01 i n range 150°- 250 # These f i g u r e s are u n r e l i a b l e , as the sample c o u l d not be measured without c h a r r i n g . -29-' TABLE H V i s c o s i t y of Hexacosane f^^Hg^) General equation i n the A.S.T.M. form: l o g l o g (V+0.6) B - 3 # 2 4 l o g rp . o . 8 8 3 where V i s the kinematic v i s c o s i t y i n c e n t i s t o k e s T i s the absolute temperature (Constants were obtained by method of s e l e c t e d p o i n t s ) t°c D e n s i t y d Kinemat i c v i s e . V es. Dynamic . v i s e . •7 =>«cp. ? e p . (others) 60 0.7788 6.383 4.971 S c h m i d t 2 5 70 0.7724 5.277 4.076 80 0.7659 4.370 3.346 5.109 (60°) 90 0.7593 3.695 2.843 1.790 (120°) 100 0.7529 3.197 2.407 110 0.7463 2.745 2.048 120 0.7398 2.388 1.767 130 0.7332 2.134 1.564 140 0.7266 1.907 1.385 150. 0.7200 1.699 1.224 160 0.7136 1.53 1.09 170 0.7070 1.41 0.99 180 0.7004 1.28 0.90 190 0.6939 1.19 0.82 200 0.6861 1.10 0.76 210 0.6794 1.02 0.69 220 0.6725 0.95 0.64 230 0.6653 0.87 0.58 240 0.6585' 0.82 0.54 250 0.6512 0.77 0.50. 260 0.6442 • 0.72 0.47 270 0.6370 0.70 0.44 280 0.6299 0.68 0.43 Accuracy - approx. X 0.005 i n range 60 - 150° 2 0.01 i n range 150°- 250° 2 0.02 i n range 250°- 280° O O O ^ O O v> ^ <*> N >c «S FIGURE X F I G U R E 2 E P/ot of A.S.T.M. Equation /of /of (vTt0.e) = A /ogT + d /OK Hexacosane and Ocfaa/ecane FIGURE a r -30-In the A.S.T.M. Equations the "best tbCu was found by experiment i n both cases to be 0.8, which i s , the standard value f o r a l l petroleum o i l s . The constants A and B were determined by the method o f s e l e c t e d p o i n t s , and may be s l i g h t l y d i f f e r e n t than i f determined by l e a s t squares. Nissan's Yiseosity-Temperature R e l a t i o n s h i p s : 33 Nissan showed the r e l a t i o n s h i p between the v i s c o -s i t i e s of a l l l i q u i d s , a s s o c i a t e d and unassociated, i n a very comprehensive a r t i c l e . He points out that the graph of Iff - A e ' ^ / ^ . i s not a s t r a i g h t l i n e s i n c e "b" v a r i e s w i t h temperature. He suggested that T-^p^/T (or Tg^fj i s a funda-mental f u n c t i o n f o r c o n s i d e r i n g dynamic p r o p e r t i e s , and that "b" i n the above equation i s the same f u n c t i o n of T^/T f o r a l l the normal paraffins*. Thus: p l o t t i n g T /T against B l o g l ^ gives a " s p e c i f i c v i s c o s i t y curve" f o r the homologous s e r i e s . He showed that a l l s e r i e s of l i q u i d s or i n d i v i d u a l l i q u i d s would g i v e s i m i l a r curves which could be r e l a t e d i n a simple equation to the " s p e c i f i c curve" of the p a r a f f i n s . He proposed that f o r any l i q u i d , f o r the same Tg/T: .log(r^) » C 4 D l o g (t)f) where XJi - v i s c o s i t y of l i q u i d considered * v i s c o s i t y of the p a r a f f i n s . Thus knowing any two experimental values of fji , the v i s c o s i t y of any l i q u i d can be c a l c u l a t e d over a wide temperature range. He used the p a r a f f i n s as the b a s i s f o r -31-a l l the l i q u i d s s i n c e the values f o r £j» f o r each TB/T are a c c u r a t e l y known over a wide range. Since he used the p a r a f f i n s as a b a s i s , but had data on no higher member i n the s e r i e s than c i 8 H 3 Q f that only to 100°C, i t was thought to be of i n t e r e s t to see how these r e s u l t s over a wide temperature range com-pared w i t h h i s s p e c i f i c curve. A p l o t was therefore made of TB/T against l o g o f v i s c o s i t y i n c e n t i p o i s e s f o r the r e s u l t s f o r hexacosane and octadecane. (See Figure X I I I ) . Then a l l the a v a i l a b l e data f o r the lower members of the 27 s e r i e s , taken from The Texas Company's " P h y s i c a l Constants", were surimposed on the same graph. The r e s u l t s were r e -markably good, as can be seen. Ho attempt was made to t e s t Nissan's equations. The graph (Figure X I I I ) i n d i c a t e s good agreement, and a check on Nissan's values f o r f o r T/T from 0.50 to 0.99 shows clo s e agreement throughout. Since has been de-termined very a c c u r a t e l y f o r the lower p a r a f f i n s , t h i s work would not change the r e s u l t , although i t d e f i n i t e l y s t r e n c h -ens them. The b o i l i n g point of hexacosane at atmospheric pressure was obtained by applying Ramsay and Young's r u l e : Ta s Ta' f o r two substances c h e m i c a l l y r e l a t e d . T B V The f i g u r e s were again taken from The Texas; 27 Company's " P h y s i c a l Constants" , and a c o r r e c t i o n was Plot of log fp against ^*/r for Hexcicosane and Octadecane compared to other members of their homologous series. t7^ 0I4-. XoiJ o lb oib K or/ X -at ** 9 too* "sB-0-8" X CZ6 H i * • c is Use o others as marked (Texas Co.") 0.2 0.3 /.o Z.O 3.0 Viscosity in centipoises (/cy) FIGURE -32-a p p l i e d , since i t was found that i n the normal p a r a f f i n s e r i e s , as the members of the s e r i e s become f u r t h e r removed from the d e s i r e d member, the equation gives a higher and higher b.p. f o r that member. Since the r i s e i n b.p. appeared to progress r e g u l a r l y , the equation was a p p l i e d t o s e v e r a l members than ext r a p o l a t e d to zero d i s t a n c e from hexacosane. This method gave a b o i l i n g point of 41S°C at atmospheric pressure f o r hexacosane. The r e s u l t s appear to have j u s t i f i e d the method. V i s c o s i t y - S u r f a c e Tension R e l a t i o n s h i p s ; An attempt was made to f i n d a s t r a i g h t - l i n e r e -l a t i o n s h i p between the v i s c o s i t y and the surface t e n s i o n of the p a r a f f i n s i n v e s t i g a t e d . 34 The equation of Sharma , as reported i n Chemical A b s t r a c t s : l o g )( = M log^X+ C di d not h o l d f o r e i t h e r kinematie v i s c o s i t y fj/) or dynamic v i s c o s i t y (r7 ), S i m i l a r l y , the equation of S i l -35 verm an and Roseveare : X * - (A/y) + B did not give a s t r a i g h t l i n e . The equation of _ 36 B u e l l e r -33-or w i t h a d j u s t a b l e constants as reported i n the Chemical 37 A b s t r a c t s as recommended by T r i p a t h i : l o g l o g £7 = m f l * + C was then p l o t t e d . (Figure XV). I t did not give a s t r a i g h t l i n e over the whole range, but d e f i n i t e l y showed p o s s i b i l i t i e s . To i n v e s t i g a t e i t f u r t h e r , i t was 38 f i r s t necessary to c o n s i d e r the v a l i d i t y of Souder 1s v i s c o s i t y - d e n s i t y . r e l a t i o n s h i p s on which i t was based. . Souder p l o t t e d the l o g l o g of «7 i n m i l l i -e10 e10 ' poises at constant pressure a g a i n s t the d e n s i t y i n grams per cc of a great many l i q u i d s , and obtained a l i n e a r r e l a t i o n s h i p over the intermediate ranges, w i t h i n c r e a s i n g curvature near the m.p. and b.p. I n the s t r a i g h t - l i n e r e g i o n s , t h e r e f o r e : l o g l o g ( r ? m p ) . - md 4 C He found the two constants to be the same f o r most of the l i q u i d s , w i t h "Mi" approximately 3.95 and C * -£.9 He then formed a " v i s c o s i t y - c o n s t i t u t i o n a l index" I « m M (where M i s the molecular weight), and found i t could be treated i n the same manner as the Para-chor, and be b u i l t up w i t h good accuracy from equivalents and increments. His equations were t e s t e d , and found to h o l d w e l l i n ranges up to 100°C (Figure XIV); but the values obtained f o r " k n were i n both cases l a r g e r than those expected. These values also increased markedly w i t h -34-temperature, u n l i k e the values for the lower homologs which Souder considered. Again, the comparison of the ob-served v i s c o s i t y - c o n s t i t u t i o n a l index " I " w i t h h i s c a l -c u l a t e d " I " was good only as l o n g as we stay i n the r e -s t r i c t e d range. This agrees w i t h h i s work i n one sense; hut i t 41 also agrees w i t h S r i n i v a s a n and Prasad , who s t a t e t h a t Souder's equation does not apply a c c u r a t e l y even to un-a s s o c i a t e d organic l i q u i d s f o r the e n t i r e range f o r which measurements have been made. Since a comprehensive equa-t i o n was d e s i r e d to r e l a t e f7 and ^ , i t was decided to modify Souder 1 s equation to give a l i n e a r r e l a t i o n s h i p , and see what r e s u l t s eould be obtained. The m o d i f i c a t i o n was not d i f f i c u l t , since the log of a l o g i s a v e r y power-f u l method of graphing, and a s t r a i g h t l i n e can be f o r c e d i n many d i f f e r e n t Ways. Care must be taken, however, to see that the term that i s logged twice be greater than 1.0 over a l l p r a c t i c a l ranges, s i n c e i f i t i s between 0 and 1.0 a complex number r e s u l t s . The f i r s t attempt was to form an equation o f the type: l o g l o g ((] m_+<*0 » md + B S t r a i g h t l i n e s were obtained w i t h l o g l o g (|7mp -1*2) s 3.58 d - 2.56 f o r hexaeosame, and l o g l o g ( H -0.2) » 3.54 d - 2.57 f o r octadecane. / mp This type of equation shows d e f i n i t e p o s s i b i l i t i e s -35-hecause of the s i m i l a r i t y of the two constants m and B; hut i t i s awkward having a v a r i a t i o n - i n noC n. and m i l l i -poises are not the u n i t s used p r a c t i c a l l y . Therefore c e n t i -poises were s u b s t i t u t e d , and s t r a i g h t l i n e s were obtained w i t h l o g l o g (r7 +• 0,8) « 6.46 d - 5.15 f o r hexacosane, ' ep and , l o g l o g ( l ^ 0 p + 0.8) - 7.55 d - 6.07 f o r octadecane. (See F i g u r e XIV). These showed more promise because o f the constancy 0f «^»»t so B u e l l e r ' s work was then i n v e s t i g a t e d w i t h t h i s i n mind. B u e l l e r u t i l i z e d the f a c t s that the Parachor, fpf = M& 4 . i s constant over a wide range, and that Sender's v i s c o s i t y - c o n s t i t u t i o n a l index, I = m M i s a l s o constant; and he combined them to form the equation: l o S l O l o S l O 7mp - A J T * * B This equation n a t u r a l l y f a l l s down where Souder's work f a l l s down, and i s hence only a p p l i c a b l e to the lower homologs and t o p a r t i c u l a r temperature ranges. For example, he found that i / P * 1.2, but suggested there was a tendency f o r i / P to increase as the carbon chain lengthens. I n both cases observed, i / P was found to have a value of approximate-l y 1.3, which i s somewhat h i g h e r . e ® ® ^ Q> 5 S .5s o cr \ 0 + 3 ^0* N N oo _• • * 0 ^ o II (t (I 1 1 Vj v) V V. V v£ £ i£ flOURE Ail -36-. B u e l l e r ' s equation when p l o t t e d was found, as expected, t o hold f o r o n l y part of the r e g i o n i n v e s t i g a t e d . (See Figure XV). An adjustment was therefore made s i m i l a r to the one made on Souder's equation, and s t r a i g h t l i n e r e l a t i o n s h i p s were obtained as f o l l o w s : l o g l o g ( r 7 m p - 1.2) r 1.41o /* - 3.02 f o r hexacosane, and l o g l o g ItJ ^0.2) • l . E o J f * - 2.59 f o r octadecane. These were corsidered to be too awkward f o r any use, having three v a r i a b l e constants, so c e n t i p o i s e s were again s u b s t i t u t e d , and the r e s u l t s were l o g l o g frt - 0.8) = 2.49 if ^  - 5.86 f o r / cp hexacosane, and l o g l o g (p o p - 0.8) = 2.55 0^" - 6.09 f o r octadecane. fSee Figure XV). A l l constants were obtained by the method of s e l e c t e d p o i n t s . Three constant equations are o r d i n a r i l y u n d e s i r -able as too cumbersome f o r p r a c t i c a l use; but the s i m i l a r i t y of the constants i n these two equations, and the f a c t that they hold over such a wide range of temperature f o r two normal unassociated l i q u i d s warrant t h e i r c o n s i d e r a t i o n . -37-The equation: 1 0 S l o l o 6 l 0 (Pep**» - °*** D may w e l l be the best e x i s t i n g equation r e l a t i n g v i s c o s i t y and surface tension at equal temperatures. F u r t h e r i n v e s t i g a t i o n i n the homologous s e r i e s may i n d i c a t e there i s a simple r e l a t i o n s h i p between the constants. The closeness of the slope of the two equations and the i d e n t i c a l constants [o£- 0.8) cannot be chance. I t a l s o should be noted that Nissan's work, p r e v i o u s l y discussed, shows that the v i s c o s i t y of a l l the normal para-f f i n s at t h e i r b.p. at atmospheric pressure, i s 0.21 cp. Thus 1 o 6 I Q l 0S20 ( 9 * ^ never be a complex value f o r the p a r a f f i n s , s i n c e cCm 0.8, and (9+^) w i l l always be greater than 1.0 f o r the e n t i r e ranges at atmospheric pressure. This may be of fundamental s i g n i f i c a n c e . Other R e l a t i o n s h i p s : No attempt was made to r e l a t e v i s c o s i t y and vapour pressure w i t h the observed r e s u l t s . Since most of . 39 the e x i s t i n g r e l a t i o n s h i p s , such as those of Othmer and 40 Madge , depend on the Arrhenius equation: ( 1/? ) = A e B/HT and s i n c e i n the p l o t of logr? against l/T as suggested by Andrade (Figure XI) the r e s u l t s were as to be expected ( s l i g h t convexity to the JL/T a x i s ) , f u r t h e r i n v e s t i g a t i o n would probably only have s u b s t a n t i a t e d the e x i s t i n g r e l a t i o n s h i p s without adding t o them. -38-Higher homologs of a s e r i e s u s u a l l y f o l l o w two curves, one f o r the even and one f o r the odd; and there may he p e r i o d i c d i s c o n t i n u i t i e s . Since only three even members of t h i s s e r i e s were i n v e s t i g a t e d , l i t t l e comparison can be 5 made i n t h i s r e s p e c t . Seyer, et a l , found C H d e f i n i t e l y 529 60 i n a d i f f e r e n t s e r i e s than the evens with respect to beha-v i o u r .neiar=: the melting p o i n t . Nissan's r e l a t i o n s h i p s , however, (See Figure X I I and d i s c u s s i o n ) , d e f i n i t e l y show the lower odd members up to C^Hgg to be i n step w i t h the evens. Whether the value given f o r C^yHgg i s In e r r o r , or whether i t i s the s t a r t of a new odd s e r i e s through C29 H60 * s a < i a e s * i o n f° r f u r t h e r i n v e s t i g a t i o n . 5 Seyer, et a l , also found that Cg^HgQ e x h i b i t e d some anomalous c h a r a c t e r i s t i c s , and p o s s i b l y was the s t a r t 0 of a d i s c o n t i n u i t y i n the even s e r i e s . I t d e f i n i t e l y appears to s t a r t a d i s c o n t i n u i t y i n the behaviour of the even s o l i d s ; but t h i s i n v e s t i g a t i o n has not shown any break i n l i q u i d p r o p e r t i e s between the lower members o f the s e r i e s and Cft/.BL.. Again, f u r t h e r i n v e s t i g a t i o n i s 26 54 necessary. -39-SUMMARY (1) The d e n s i t i e s and surface tensions of C^g, C24» 8 1 1 4 G26 ^ t l i e v i s o o s i t i e s o f a& d G2g ^ere mea-sured from t h e i r m e l t i n g p o i n t s to 280°C. (2) The l i m i t i n taking such measurements was found to he 280 GC, because o f the c h a r a c t e r i s t i c s of a v a i l -able bath l i q u i d s and because of the c h a r r i n g of the samples at t h i s temperature. (3) Equations were c a l c u l a t e d f o r the temperature c o e f f i c i e n t s of the d e n s i t i e s over the observed range. (4) Equations i n the form of Ramsay sad S h i e l d s were c a l c u l a t e d f o r the molar surface energies over the observed range. (5) The values of the Paraehors were found to be reasonably constant and to check c l o s e l y w i t h c a l c u l a t e d values over the observed range. (6) Equations i n the A.S.T.M. form were c a l c u l a t e d f o r the v i s c o s i t i e s over the observed range, and were found to give good, s t r a i g h t - l i n e r e l a t i o n s h i p s . (7) Nissan's r e l a t i o n s h i p of T B/T to l o g £7 was tested over a much l a r g e r range than he p r e v i o u s l y had a v a i l -able to t e s t . I t checked very w e l l . (8) The b o i l i n g point of hexacosane was c a l c u l a t e d to be 413°C at atmospheric pressure. This f i g u r e was checked by applying i t i n Nissan's r e l a t i o n s h i p s . -40-(9) B u e l l e r ' s equation! l o g logrt = was modified to l o g , ^ log_« (lO +0.8) « A + B, and 10 10 / cp T was found to give such e x c e l l e n t r e s u l t s f o r C^Q and C g g that i t s f u r t h e r i n v e s t i g a t i o n i s recommended. 'This modi-f i c a t i o n i s the only known r e l a t i o n s h i p between surface tension and v i s c o s i t y to hold over complete l i q u i d ranges from m.p. to b.p. -41-BIBLTQGRAPHY 1. Peterson. Z e i t . Electrochemie. 12, 141 (1906) 2. S o r a b j i . J. Chem. Soc. 47, 39 (1885) 3. Keays. J. L.. Master's TheBis, U n i v e r s i t y of B r i t i s h Columbia (1941) . 4. P i p e r . S. E. et a l . B i o . J . 25, 2072-2094 (1931) 5. Seyer. W. P.. P a t t e r s o n . R.F.. and Keays. J.L.. J. Am. Chem. Soc. 66, 179 (1944) 6. Hildebrand and Wachter. J . Am, Chem. Soc. 51, 2487 (1929) 7. Deansley. R.M.. and Carle t o n . L.T.. J. Phy. Chem. 45 1104-23 (1941) _ , 8. Christensen. B.E.. and King. A.E.. Ind. Eng. Chem (Anal.Ed.)1 8, 194 (1936) 9* Sugden. S.. Jour. Chem. S o c , 119, 1483 (1921) 10. Richards. T. W.. Speyers. C.L.. and Carver. E.E.. J. Am. Chem. Soc. 46, 1196 (1924) 1 1 • S t e i n e r . L.A.. Petroleum 6, 50 (1943) 12. Cannon. M.R.. and Fenske. M.R.. Ind. Eng. Chem. (A n a l . Ed.) 16, 708 (1944) 13. Fry. E.M.. and Baldesehwieler. E.L.. Ind. Eng. Chem. (An a l . Ed.) 12, 472 (1940) 14. Penther and Pompeo. E l e c t r o n i c s 14, 20-22 (1941) 15. S t e i n e r . L.A.. Nature 150, 345 (1942) 16. Speakman. E.A.. Review of S c i . I n s t r . 8, 502 (1937) 17. C a l i n g a e r t . Beatty, Kuder. and Thompson. Ind. Eng. Chem. 33, 103 (1941) 18. K r a f f t , Reported i n I n t e r n a t i o n a l C r i t i c a l Tables 19. Dover and Hensley. Ind. Eng. Chem. 27, 388 (1935) 20. R i c h t e r . G.H.. "Textbook of Organic Chemistry" 21. M o K l t t r i c k . J . I n s t . Pet. Tech. 23, 630 (1937) ' -42-22. Tan Hook, A. ana S i l v e r . I . . J . Chem. Phys. 10, 686-9 f1942) 23. E g l o f f . " P h y s i c a l Constants of Hydrocarbons* 24. Bnchler. Ind. Eng. Chem. 27, 1425 (1935) 25. Schmidt. A.. S o h o e l l e r . V.. and E b e r l e i n . K.. • B e r 74B 1313-24 (1941) 26. Wilson and Bahlke. Ing. Eng. Chem. 16, 115 (1924) 27. reported by M.P.Doss, The Texas Co., " P h y s i c a l Constants of the P r i n o i p a l Hydrocarbons" 28. Schenck. R.. and K i n t z i n g e r . M.. Rec. t r a v . chim. 42. • 759-64 (192^3) 29. Andrade. E.N.. Nature 125 , 309 (1930) 30. Evans. E.B.. Second World P e t r . Congress, P a r i s , 2 (1937) 3 i » Walther. Petroleum 26, 755 (1930) World P e t r . Congress 2, 419 (1933) 32. Ubbelohde and Agthe. (1912) L a n d o l t - B o r n s t e i n T a b e l l e n , 3rd supp. 3 3 « Nissan. A. H.. P h i l . Mag. 32, 441-56 (1941) 34. Sharma. R.K.. Quart. J . Indian Chem. Soc. 2, 310 (1925) 35. Silverman. P.. and Roseveare. W.. J. Am. Chem. Soc. 54, 4460 (1932) 36. B u e l l e r . C.A.. J. Phys. Chem. 42, 1207 (1938) 37. T r i p a t h i . R.C.. J. Indian Chem. See. 19, 51-54 (1942) 38. Souder. Mptt. J r . . J . Am. Chem. Soc. 60, 154 (1938) 39. Othmer. P.. and C o i w e l l . J . . Ind. Eng. Chem. 37, 1112 (1945) 40. Madge. E.W... Physies 5 , 39 -41 (1939) 41. S r l n i v a s a n . M.E.. and Prasad. B.. P h i l . Mag. 33, 258 (1942) -43-APPEIDIX REDOMMEHDA T10 US FOR FUTURE WORK (1) I n v e s t ! gat cars f o l l o w i n g t h i s work should he warned of the danger of the p a r a f f i n hath i n the r e g i o n o o 250 C to 280 C. I t f l a s h e s v e r y e a s i l y i n t h i s temperature range, and sus t a i n e d burning i s d i f f i c u l t to prevent. The bath should be as completely enclosed at the top as p o s s i b l e , w i t h holes only f o r s t i r r i n g , a d j u s t i n g the viscometer l e v e l , and t i l t i n g the c a p i l l a r i m e t e r * F i r e e x t i n g u i s h i n g equipment, p r e f e r a b l y o f the foam type, should be at hand during a run. Externally-wound heating elements r a t h e r than immersion hea-t i n g was attempted to el i m i n a t e hot spots, but i t did. not help a t a l l . The wax f l a s h e s . (2) In f u t u r e , a l l p a r a f f i n samples i n v e s t i g a t e d should be p u r i f i e d by r e c r y s t a l l i z a t i o n w i t h i n a month before they are used. Only i n t h i s way can t h e i r absolute p u r i t y be guaranteed. Freezing and s e t t i n g p o i n t determina-t i o n s are not s u f f i c i e n t l y accurate c r i t e r i a , because o f the formation of isomers that may behave s i m i l a r l y . (3) A p r e c i s i o n e l e c t r o n i c timer i s a d e f i n i t e n e o e s s i t y f o r accurate v i s c o s i t y determinations^ f o r reasons 15 discussed i n the body of t h i s t h e s i s . S t e i n e r gives the address of an E n g l i s h manufacturer of such timers. American 13 manufacturers also make them. (See F r y and Baldesehweiler 14 and Penther and Pompeo )• I t should be noted that a timer i s needed wi t h a p r e c i s i o n of only l/lOO of a second, but wi t h a c a p a c i t y t o work to 2000 or 3000 seconds f o r g e n e r a l usefulness around the l a b o r a t o r y . E l e c t r o n i c timers are made w i t h a great range of p r e c i s i o n and of t o t a l - t i m e c a p a c i t y . (4) The use of American types of viscometers should 12 be i n v e s t i g a t e d . Cannon and Fenske. r e p o r t very low K i n e t i c Energy er r o r s w i t h t h e i r "master viscometers" and describe many u s e f u l - t y p e s of viscometers i n d e t a i l . I n p a r t i c u l a r , t h e i r micro-viscometer, which r e q u i r e s as l i t t l e as 0.25 ec of the substance f o r accurate work, i s of i n t e r e s t , as the B r i t i s h viscometers r e q u i r e a considerable amount of the sample, and the high temperatures r u i n i t a l l . V i s c o s i t y measurements could not be taken on C g 4 because of the laek o f pure m a t e r i a l , yet there were at l e a s t 2 cc of i t on hand. (5) Water should be used as a bath l i q u i d up to 90^C, and the bath d r i e d as w e l l as p o s s i b l e afterwards. I t s advantages f a r outweigh i t s disadvantages. P o s s i b l y the wood block i n s i d e could be replaced by an a l l - m e t a l block to f a c i l i t a t e d r y i n g the bath out. (6) A small bath made of 70-mm pyrex tubing w i t h 500-watt externally-wound h e a t i n g wires and standard magnesia pipe i n s u l a t i o n around i t was t e s t e d f o r use at v e r y h i g h tem-peratures. I t was found to be not b i g enough f o r tne v i s -cometer or c a p i l l a r i m e t e r , but h e l d a d i l a t o m e t e r n i c e l y . Temperatures i n s i d e can be c o n t r o l l e d reasonably w e l l by s t i r r i n g and by v a r y i n g the r e s i s t a n c e i n the h e a t i n g c i r c u i t . Jtt was p a r t i c u l a r l y good f o r t e s t i n g bath l i q u i d s a t high tern-peratures. -45-(7) Nissan's work appears t o be v e r y fundamental., and f u r t h e r v i s c o s i t y determinations w i t h the normal para-f f i n s should be r e l a t e d to i t . (8) The m o d i f i c a t i o n as described of B u e l l e r ' s equation r e l a t i n g v i s c o s i t y and surface t e n s i o n appears to have enough merit to warrant f u r t h e r i n v e s t i g a t i o n . 

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