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UBC Theses and Dissertations

The vapour pressures of the cis and trans isomers of decahydronapthalene Nemetz, Herman 1938

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THE VAPOUR PRESSURES OF THE OIS AND TRANS ISOMERS OF DECAHYDRONAPHTHAL1NE b y Herman Nemetz A T h e s i s S u b m i t t e d f o r the Degree of MASTER OF APPLIED SCIENCE i n the Department o f CHEMISTRY The U n i v e r s i t y of B r i t i s h Columbia A p r i l 1933 TABLE OF CONTENTS. INTRODUCTION Page A. Reasons f o r r e s e a r c h . 1 B. P r e v i o u s i n v e s t i g a t i o n s . 2 PART I S e p a r a t i o n of the C i s and Trans Isomers. A. D e s c r i p t i o n of the apparatus 2 B. E x p e r i m e n t a l procedure 3 C. E x p e r i m e n t a l r e s u l t s 4 D-. Remarks 8 P u r i f i c a t i o n by F r a c t i o n a l C r y s t a l l i z a t i o n . A. Method 3. P u r i t y of the f i n a l p r o d u c t s PART I I D e t e r m i n a t i o n of the Vapour P r e s s u r e s of  the C i s and Trans Isomers. A. D e t a i l s of the apparatus 10 B. E x p e r i m e n t a l procedure 11 C. E x p e r i m e n t a l r e s u l t s 14 CONCLUSION BIBLIOGRAPHY 17 18 DIAGRAMS F a c i n g Page F i g u r e 1. Low P r e s s u r e r e c t i f i c a t i o n column 2 F i g u r e 2. Vapour p r e s s u r e a p p a r a t u s 10 Graph 1. Vapour p r e s s u r e curve f o r the c i s isomer (p. v s . T) Graph 2 . Vapour p r e s s u r e curve f o r t h e t r a n s isomer (P. v s . T) Graph 3. Vapour p r e s s u r e c u r v e s f o r c i s and 14 t r a n s isomers. (P. v s . T) , Graph 4. Log P VS '/-[-£OI> the c i s isomer 15 Graph 5. Log P. VS'/ffor the t r a n s isomer 16 Graph 6. Log Log P VS '/jfor t he c i s and t r a n s i s o m e r s . 17 12 13 THE VAPOUR PRESSURES OF THE GIS AND TRANS ISOMERS OF DECAHYDRONAPHTHALENE INTRODUCTION A. Reasons f o r the r e s e a r c h . Decahydronaphthalene ( C i o H i a ) , o r d e c a l i n , i s a hydrocarbon of the s e r i e s C nHg n..g. A t p r e s e n t , v e r y l i t t l e i s known about the n a t u r e of dina p h t h e n e s . A l t h o u g h d e c a l i n has l i m i t e d use i n the i n d u s t r i a l w o r l d , ( c h i e f l y as a solvent) I t i s of g r e a t t h e o r e t i c a l i n t e r e s t as i t e x i s t s i n i s o m e r i c forms. M o h r 1 f i r s t p o s t u l a t e d the p o s s i b i l i t y o f the e x i s -t e n c e of two s t a b l e forms of decahydronaphthalene, and l a t e r Wight/nan^ showed t h a t t h e r e might be f i v e p o s s i b l e i s o m e r i d e s f o r t h i s h y d r o c a r b o n . I t i s g e n e r a l l y b e l i e v e d t h a t two i s o m e r i c forms e x i s t , i..e. the c i s and the t r a n s . The o b j e c t o f t h i s r e s e a r c h i s , i n p a r t , t o determine some o f the p h y s i c a l p r o p e r t i e s o f the pure c i s and t r a n s i s o m e r s , w i t h the hope t h a t when most of t h e i r p h y s i c a l p r o p e r t i e s have been measured, a d e f i n i t e c o n c l u s i o n may be a r r i v e d a t , t o e i t h e r prove o r d i s p r o v e the e x i s t e n c e o f more than two isomers f o r t h i s h y d r o c a r b o n . The t a s k o f c o r r e l a t i n g a l l these p h y s i c a l c o n s t a n t s has been undertaken by Dr, 7/.F. Seyer, of the U n i v e r s i t y of B r i t i s h Columbia, who has s u p e r v i s e d the I Mohr, J . p r . Chem. 98, 315 (1918) ; 103, 316 (192S) Wightman,. J . Chem. Soc. 127, 1421 (1925). ^X^/lfiSloN //a MANOM£TOl UNIT low PzESsuef RECTIFICATION COLUMN. fVto. ins Fi&l - 2 -f o l l o w i n g work. B. P r e v i o u s i n v e s t i g a t i o n s . Dr. W . F . Seyer and R.D. W a l k e r 5 s e p a r a t e d the pure c i s and t r a n s isomers and then measured t h e i r r e f r a c t i v e i n d i c e s , d e n s i t i e s , f r e e z i n g p o i n t s and b o i l i n g p o i n t s . T h e i r r e s u l t s are g i v e n i n Table I . T a b l e I D g 0 N^ Q F.P. °C B.P. °G C i s form 0.8963 1.48115 - 43.19*0.2 194.6 Trans form 0.8699 1.46968 - 31.29+0.2 185.5 R e s u l t s of o t h e r i n v e s t i g a t i o n s and t h e i r i n v e s t i g a t o r s may be found i n the r e s e a r c h of R.D. W a l k e r 3 . PART I / S e p a r a t i o n o f the Q i s and Trans. Isomers. A. D e s c r i p t i o n o f the a p p a r a t u s . The a p p a r a t u s , shown i n F i g . 1, used t o s e p a r a t e the cis. and t r a n s i s o m e r s , was d e s i g n e d by Dr. W . F . Seyer and was the same as used by R.D. Walker i n h i s r e s e a r c h . The column i s 95 in c h e s i n l e n g t h and the d i s t i l l i n g b u l b has a c a p a c i t y of 3000 C.G.'s. I n s t e a d o f a gas burner, a h e a t i n g element was used f o r d i s t i l l a t i o n p u r p o s e s , 3 Walker, R.D. M.A.Sc.. T h e s i s , U.B.C. (1937) - 3 -B. E x p e r i m e n t a l p r o c e d u r e . The d e c a l i n used was s y n t h e s i z e d by the Eastman Kodak Go. , — i t s c o m p o s i t i o n was IZfo t r a n s , as determined by r e f r a c t i v e index and d e n s i t y measurements. The s t i l l was charged and s e t i n t o o p e r a t i o n w i t h .2000 c.c. of t h i s m i x t u r e , which h a d been washed w i t h c o n c e n t r a t e d HgS0 4 and n e u t r a l i z e d w i t h NaOH and water, and then d r i e d * The v o l t a g e on the h e a t i n g c o i l around the g l a s s column was a d j u s t e d to 14 v o l t s , then g r a d u a l l y r a i s e d , to 16 v o l t s — t h i s h e a t i n g c o u n t e r a c t e d heat l o s s due t o r a d i a t i o n . The c u r r e n t through the e l e c t r i c h e a t e r was ke p t between 4.25-5 amperes; the p r e s s u r e as c l o s e to.10 m i l l i m e t r e s as p o s s i b l e , and the temperature between the range o f 6G°C - 70 ° C . The s t i l l was run c o n t i n u o u s l y u n t i l about 200 c.c's of "bottoms" were l e f t * — ZL — C. E x p e r i m e n t a l r e s u l t s . Each, o f the f i v e f r a c t i o n s o f each r e c t i f i c a t i o n was a n a l y z e d , and the f o l l o w i n g r e s u l t s were o b t a i n e d . R e c t i f i c a t i o n #1 CHARGE. 2000 c.c. Eastman Kodak d e c a l i n , a c i d washed then n e u t r a l i z e d and d r i e d . N g Q - 1 . 4 7 9 65 ( 1 3 $ t r a n s ) "D^Q 0 . 8 9 20 PRESSURE I N APPARATUS - 10 mm. CONDENSER WATER - a p p r o x i m a t e l y c o n s t a n t a t 20°G. RESULTS: F r a c t i o n 1 2 3 4 5 Volume ( c . c . ) 1 2 1 3 3 2 7 4 3 3 5 2 290 N^Q . . 1 . 4 7 0 8 1 1 . 4 7 1 7 0 1 . 4 7 9 7 5 1 . 4 8 1 1 3 1 . 4 8 2 2 9 fo C o m p o s i t i o n ( t r a n s ) 9 1 8 2 1 2 0 — % C o m p o s i t i o n ( c i s ) 9 1 8 8 8 100 R e c t i f i c a t i o n $ 2 CHARGE - 2 0 2 5 c.c. Eastman Kodak d e c a l i n — a c i d washed, n e u t r a l i z e d and d r i e d . NgQ = 1 . 4 7 6 9 5 ( 1 3 $ t r a n s ) D^Q Z 0 . 8 9 2 0 PRESSURE IN APPARATUS + 10 mm. CONDENSER WATER - c o n s t a n t a t 20°C. • RESULTS; F r a c t i o n 1 2 3 4 i 5 Volume ( c . c . ) 2 2 5 240 74*5 4 0 3 Residue • H g 0 1 . 4 7 0 7 6 1 . 4 7 4 5 5 1 . 4 8 0 9 8 1 . 4 8 2 8 3 fo Composition ( t r a n s ) 92 57 3 - — » fo Gomposition ( c i s ) 8 4 5 9 7 ____ - 5 -R e c t i f i c a t i o n #5 CHARGE - 1755 c.c, made up of f r a c t i o n s #4 and #5 of r e c t i f i c a t i o n #1, and f r a c t i o n s #3 and #4 of r e c t i f i c a t i o n §Z. • •M^ Q = 1.48166 PRESSURE IN APPARATUS -CONDENSER WATER ' -10 mm. c o n s t a n t a t 20°C RESULTS; F r a c t i o n "Volume ( c . c . ) 1 162 N D 20 2 .423 3 540 4 203 5 114 1.48024 1.48108 1.48113 1.48118 1.48113 % C o m p o s i t i o n ( t r a n s ) 7.5 0 0 0 fo C o m p o s i t i o n ( c i s ) 92.5 100 100 100 0 100 R e c t i f i c a t i o n f4 CHARGE TD 1490 c.c. made up of f r a c t i o n s 1 and 2 of r e c t i f i c a t i o n §1; f r a c t i o n s 1 and 2 o f r e c t i f i c a t i o n #2; 572 c.c. o f h i g h t r a n s c o n t e n t , a c i d washed (R.D. Walker) N g 0 = 1.46883 PRESSURE IN APPARATUS CONDENSER WATER 10 mm* co n s t a n t a t 20°0 RESULTS: F r a c t i o n Volume ( c . c . ) 1 230 D •go 1.46192 % Co m p o s i t i o n ( t r a n s ) — $ Co m p o s i t i o n ( c i s ) 2 3 4 5 490 240 195 141 1.46918 1,46958 1.46968 1.47100 100 100 100 0 0 . 0 - 6 R e c t i f i c a t i o n CHARGE - 2000 c.c. unwashed Eastman Kodak Co. d e c a l i n . PRESSURE IN APPARATUS - 10 mm. CONDENSER WATER - c o n s t a n t a t 20°C RESULTS: F r a c t i o n Volume (cc.) 1 2 . 3 4 5 283 135 140 173 92 «20 1.46958 1.46953 1.46933 1.47150 1.47760 °/o C o m p o s i t i o n ( t r a n s ) — - 100 98 84 31 fo C o m p o s i t i o n ( c i s ) . 0 2 16 69 R e c t i f i c a t i o n .$6 CHARGE - 1380 c.c. Eastman Kodak Co. d e c a l i n and 900 c.c. t r a n s f r o m r e c t i f i c a t i o n $5. PRESSURE IN APPARATUS CONDENSER WATER RESULTS: 10 mm. c o n s t a n t a t 20°0 F r a c t i o n Volume ( c . c . ) If D 1 2 3 4 5 325 180 , 320 41 330 • 2 0 1.46893 1,46968 1.46968 1.469 63 1.46987 f0 Composition ( t r a n s ) — 100 100 % Co m p o s i t i o n , ( c i s ) — 0 0 100 0 99 1 - 7 -R e c t i f i c a t i o n $7 CHARGE - from r e c r y s t a l l i z a t i o n s of r e c t i f i c a t i o n s #5 and #6. PRESSURE IN APPARATUS - 10 mm. CONDENSER WATER - oon s t a n t a t 20°C 1 2 3 4 5 1.46903 1.46953 1.46958 1.46953 1.46953 - a l l over 100 % t r a n s . RESULTS: F r a c t i o n ' N D 30 Composition - 8 -D. Remarks. The samples of d e c a l i n from Eastman Kodak Go. were h i g h i n c i s c o n t e n t , whereas the samples used by R, D, Walker were h i g h i n t r a n s . Thus i t was an e a s i e r t a s k to s e p a r a t e the c i s form i n t h i s case, than was the t r a n s * A c a p i l l a r y tube was i n s e r t e d i n the l i n e l e a d i n g to the r e c e i v i n g u n i t to r e t a r d the r a t e o f d i s t i l l a t i o n * I n t h i s way a b e t t e r s e p a r a t i o n by r e c t i f i c a t i o n was o b t a i n e d . P u r i f i c a t i o n by F r a c t i o n a l R e o r y s t a l l i z a t i o n . A. Method. F r a c t i o n s c o n t a i n i n g h i g h percentage of the c i s isomer were mixed t o g e t h e r i n a dewar f l a s k , which i n t u r n , was p l a c e d i n a l a r g e r dewar and s u r r o u n d e d by s o l i d c arbon d i o x i d e . A p l a t i n u m r e s i s t a n c e thermometer and a s t i r r e r were p l a c e d i n the l i q u i d , and as soon as a c o n s t a n t f r e e z i n g p o i n t was reached, the l i q u i d was decanted f r o m the c r y s t a l s . The c r y s t a l s were m e l t e d , and the o p e r a t i o n was r e p e a t e d many times u n t i l a c o n s t a n t f r e e z i n g p o i n t was reached. C o n s i s t e n t r e s u l t s and the l e n g t h o f time the temperature remained c o n s t a n t a t the f r e e z i n g p o i n t i n d i c a t e d the p u r i t y o f the c i s i s o m e r . The h i g h t r a n s f r a c t i o n s were t r e a t e d i n a s i m i l a r manner u n t i l a c o n s t a n t f r e e z i n g p o i n t was o b t a i n e d . More d i f f i c u l t i e s were encountered w i t h t h i s isomer t h a n w i t h the t r a n s , but c o n s t a n t and c o n s i s t e n t r e s u l t s were f i n a l l y o b t a i n e d . A m e c h a n i c a l s t i r r e r was f i r s t used, but was. r e p l a c e d by a hand s t i r r e r when a c o n s t a n t temperature was approached. F o r the f i n a l r e s u l t of the f r e e z i n g p o i n t , the s o l i d carbon d i o x i d e was r e p l a c e d by an a l c o h o l and d r y i o e bat h , kept c o n s t a n t a t a p p r o x i m a t e l y 10 degrees below the f r e e z i n g p o i n t o f the isomer. B. P u r i t y of the f i n a l p r o d u c t s . Table I I shows the p h y s i c a l c o n s t a n t s of the isomers o b t a i n e d * TABLE I I P . ° 0 3 .P. °G (from Graph #5) C i s f o r m - 43.25*0.2 1.48113 193 Trans form - 3 1 . 4 9 * 0 . 2 1.469 68 185 There can be v e r y l i t t l e doubt as to the p u r i t y o f these i s o m e r s , as the v a l u e s found a r e p r a c t i c a l l y i d e n t i c a l w i t h those of R.D* Walker — who s t a r t e d w i t h a m i x t u r e of d i f f e r e n t c o m p o s i t i o n * The temperature a t the f r e e z i n g p o i n t remained c o n s t a n t f o r over one hour and the r e s u l t s were e a s i l y r e p e a t e d a f t e r l e t t i n g the pure'isomer remain i n c o n t a c t w i t h sodium w i r e f o r over two weeks. These p r o d u c t s were used i n the vapour p r e s s u r e d e t e r m i n a t i o n s . PART I I D e t e r m i n a t i o n o f the Vapour P r e s s u r e s of the G i s and Trans  Isomers. A. D e t a i l s of the a p p a r a t u s . The p r o c e d u r e f o r measuring the vapour p r e s s u r e s i n t h i s r e s e a r c h was a m o d i f i c a t i o n o f t h e s t a t i c method, de s i g n e d t o e l i m i n a t e the c h i e f source of e r r o r — i . e . presence of d i s s o l v e d substance* The g e n e r a l arrangement of the apparatus i s shown i n P i g . 2. Much the same ap p a r a t u s was used by B e l l 4 and Armstrong i n t h e i r vapour p r e s s u r e measurements of normal decane. To e l i m i n a t e any p o s s i b l e l e a k s i n t h e i r c a s t i r o n mercury r e s e r v o i r , i t was found a d v i s a b l e t o s u b s t i t u t e a s t e e l mercury r e s e r v o i r . The two upper v a l v e s were of b r a s s , whereas t h e two lower ones were o f s t e e l — t o p r e v e n t any amalgamation w i t h the mercury. A l l j o i n s were welded w i t h the e x c e p t i o n of t h a t j o i n i n g the d r y i n g tube and t h a t j o i n i n g t h e p r e s s u r e gauge. These were s e a l e d w i t h d e k h o t i n s k y cement, then p a i n t e d w i t h s h e l l a c . T h i s arrangement proved s a t i s f a c -t o r y , as i t c o u l d w i t h s t a n d a t l e a s t 100 -pounds p r e s s u r e and -4-c o u l d m a i n t a i n a vacuum o f 1 x 10 cms. The squared paper a t t a c h e d to the support P, was c a l i b r a t e d by means of a cat h e t o m e t e r . • Bulb, M, was s e a l e d on t o p r e v e n t mercury from goi n g over to the vacuum l i n e s i n case o f a l e a k , o r sudden i n c r e a s e i n vapour p r e s s u r e . 4 _ B e l l , N. and Armstrong, J.H. B.A.Sc. T h e s i s , U.B.G. (1937) - 11 -B. E x p e r i m e n t a l procedure The a p p a r a t u s was washed t h o r o u g h l y w i t h d i l u t e n i t r i c a c i d and d i s t i l l e d water, then d r i e d w i t h a c u r r e n t of dr y a i r . The mercury t o be used was p u r i f i e d by washing w i t h d i l u t e n i t r i c a c i d , then sodium carbonate s o l u t i o n and f i n a l l y w i t h water. I t was then d r i e d i n an oven a t 110°G. The apparatus was t e s t e d f o r l e a k s , then 250 c.c. of pure mercury were a d m i t t e d to the r e s e r v o i r through the lower v a l v e . The manometer, N, was used to t e s t f o r l e a k s b e f o r e the b u l b s were s e a l e d on — then the McLeod gauge was used. The appara-t u s was evacuated t o 1 x 10 cms, p r e s s u r e , and mercury was a d m i t t e d t o the gauge t h r o u g h v a l v e k, u n t i l i t s t o o d a t about 6 inches i n U. These l e g s were th e n f r o z e n w i t h s o l i d carbon d i o x i d e . With s t o p c o c k S c l o s e d , b u l b E, c o n t a i n i n g the f r o z e n pure c i s isomer was s e a l e d on t o the a p p a r a t u s . The c o n t e n t s of E were kept f r o z e n by s u r r o u n d i n g the bulb w i t h l i q u i d a i r , and S was opened to evacuate the b u l b once more. By g e n t l y h e a t i n g E to about 35°G, w i t h S now c l o s e d , and k e e p i n g F i n l i q u i d a i r , the hydrocarbon was d i s t i l l e d i n t o F; then by the same proce d u r e about 15 c.c, were d i s -t i l l e d i n t o L. The g l a s s between G, a mercury t r a p , and L, and the g l a s s from S to the h o r i z o n t a l t u b i n g was$ surrounded w i t h s o l i d carbon d i o x i d e t o p r e v e n t any o f the hydrocarbon from d i s t i l l i n g i n t o these p a r t s . F i n a l l y bulbs L, G and E were f r o z e n w i t h l i q u i d a i r , S was opened, and any o c c l u d e d a i r was removed. With a l l the sto p c o c k s and v a l v e s now c l o s e d , the apparatus was s e a l e d o f f between L and G, the - 12 -mercury l e t m e l t and a h e a t i n g c o i l wound on the exposed t u b i n g c o n t a i n i n g the vapour o f the hydrocarbon, as shown i n F i g . 2. I n s e r t e d i n a dewar f l a s k which surrounded bu l b L, were a s t i r r e r , an e l e c t r i c h e a t e r and a c a l i b r a t e d thermometer. The l a t t e r was s t a n d a r d i z e d a g a i n s t a p l a t i n u m r e s i s t a n c e thermometer. F o r temperatures below 0°G, a bath of m e t h y l a l c o h o l and s o l i d carbon d i o x i d e was used; about room temperature, the dewar was f i l l e d w i t h a l i g h t o i l which c o u l d w i t h s t a n d h e a t i n g to about 200°C. The temperature a t each p o i n t was kept c o n s t a n t f o r about h a l f an hour, and the d i f f e r e n c e i n the h e i g h t o f the mercury l e g s was read by means of a cathetometer. Above room temperature, the h e a t i n g c o i l on the g l a s s was used. The heat g i v e n out by the c o i l was a d j u s t e d to heat the vapour i n the t u b i n g to about the same temperature as the b a t h , a f t e r c o r r e c t i n g f o r r a d i a t i o n l o s s e s . F o r h i g h e r p r e s s u r e s more mercury was a d m i t t e d . A t v e r y h i g h temperatures, p r e s s u r e was a p p l i e d to f o r c e more mercury i n t o the column. The above procedure was a l s o f o l l o w e d f o r the t r a n s isomer. I n the m a n i p u l a t i o n o f the a p p a r a t u s , c a r e must be t a k e n i n a d j u s t i n g the o u t s i d e h e a t i n g c o i l , e l s e the vapour i n the g l a s s t u b i n g may be a t a d i f f e r e n t temperature than the vapour i n the b u l b . To check the temperature of the c o i l , a thermometer was i n s e r t e d i n a g l a s s tube- f i l l e d w i t h mercury -- the tube b e i n g a l s o wound w i t h the h e a t i n g c o i l . - 13 -Readings must be checked and the temperatures of both bath and c o i l must remain c o n s t a n t w h i l e r e a d i n g s are t a k e n . To overcome t h i s chance o f e r r o r , i t i s suggested that the d e s i g n of the apparatus be so a l t e r e d so as to a l l o w a minimum of vapour t o be i n the t u b i n g not heated by the b a t h . 2tS0. Ii T R A N S ^ / V 0 - 0 - - 0 - & -«0 lio - 14 -0. E x p e r i m e n t a l R e s u l t s . ' RESULTS FOR THE TRANS ISOMER P r e s s u r e ( c m s . ) L o g P _ L x 10 3 T - C o r r e c t e d t °C T 0 ,000 ':. „ 4.1305 -31.0 242.1 0.059 **1 A 2292 3.9698 ™* 21 © 2 251.9 0.172 -0.7645 ' 3.8052 -10.3 262.8 0.250 -0.6021 3*6751 - 1 .0 272.1 0.294 -0.5317 3.5411 9.3 282.4 0.569 -0.2449 3.4083 20.3 293*4 0.852 -0.0799 3.3058 29.4 302*5 -L«4x7 5 0.1688 .3.1990 39.5 312*6 2 o 2 2 5 0.3473 3.1008 49.4 322» 5 4,092 0.6119 3*0021 60.0 333.1 6 . 5 8 0 0*8182 2.9191 70*2 352,8 12.328 1*0910 2.7579 89.5 362.6 15.600 1.1931 2.6889 ,93.8 371.9 19.200 1® 2333 2.6199 103.6 381*7 21.440 X 3 312 2.5471 119.5 392.6 23.630 1.4568' 2.4351 129 » 3 402.4 34.345 1 . 5 3 5 8 2.4149 141*0 414.1 41.870 1.6219 2.3596 150.7 423.8 50.810 1.7059 2.5041 160.9 - 454.0 59.710 1.7760 2 © 2 50 2 171.3 444.4 80.480 1.9057 2*1720 187.3 460.4 113.60 139.64 17 2 * 23 214.53 2.0554 2.1449 2.2360 2.3314 2.1022 2.0580 2,0145 1.9673 202*6 213 « 3 2 23 ft 3 235.2 475.7 485.9 496*4 508.3 RESULTS FOR THE OIS ISOMER P r e s s u r e ( c m s . ) L o g P j L z 1 0 3 r C o r r e c t e d t °C T 0.000 4.1305 -51.0 242.1 0.170 -0.7696 . 3.9714 —21.3 251.8 0.229 -0.6402 3.8270 —11, 8 261.5 0.295 -0.5302 3.6738 -0.9 27 2 © 2 0.400 -0.3979 3.5448 9.0 282*1 0.535 . -0.2716 3.4200 19.3 292.4 0.565 -0.2479 3.4200 19.3 29 2»4L 0.816 -0.8883 3.2798 31.8 304.9 1*031 0.0133 3.2020 39.2 312.3 1.369 0.1364 3.1056 48.9 322*0 1.768 0.2475 3.0057 59.6 332.7 2.203 0.3430 2.9197 69 .4 342.5 3.008 0.4783 2*8377 79.3 352.4 4.740 0.67 58 2.7405 .91.8 364.9 5.688 •• 0.7549 2.5346 99*4 372.8 7.839 0.8943 2.6154 109.1 382 © 2 9.207 0.9 638 2.5866 113.5 386,2 XX e733 1.0693 2.5406 120.5 393.6 14.001 1.1461 2.4907 128.4 401.5 20.316 1.3078 3 a 4:X V 2 140.6 413.7 21.304 1,3286 2 o 3929 144.3 417.9 28.8.29 1.4593 2.3540 151.7 424.8 36.771 1.5655 2.2973 162.2 435.3 45.760 1.6605 2.2505 171.3 444.4 - 16 -P r e s s u r e (cms *) Log P J . X 1 0 3 T C o r r e c t e d t °C 59.236 1*7726 .2.1997 181.5 454.6 74.276 1.8709 3 o X 5X 5 X9 X © 7 464.8 101.47 2.0062 2«- X 0 2 2 202.6 275.7 160.05 2.2041 2.0580 212.8 485.9 1 5 6 . 3 0 2.1931 2.0580 212.8 485*9 223.80 2.3499 2.0145 223.3 496.4 The vapour p r e s s u r e curves p l o t t e d from these r e s u l t s are shown i n graphs #1, 2 and 3. Graphs #4 and 5 show the r e l a t i o n s h i p between l o g p and -X. and graph #6 shows the r e l a t i o n s h i p between l o g l o g P and -L . U s i n g a v e r y c l o s e a p p r o x i m a t i o n t h a t the l a t e n t heat of e v a p o r a t i o n , ^ , i s a l i n e a r f u n c t i o n o f the a b s o l u t e temperature, then f r o m the Cl a p e y r o n e q u a t i o n of d ^ n p a Afl , we a r r i v e a t a vapour u 1 H i p r e s s u r e e q u a t i o n o f the form, l o g 2 - L + B Log T -t- C where A, 3 and C are c o n s t a n t s . T h i s e q u a t i o n was d e r i v e d by Kiccbiiof f , and has been shown to a p p l y w i t h a maximum e r r o r of 3$ t o over s e v e n t y substances up t o t h e i r c r i t i c a l p o i n t . , U s i n g t h i s form of an e q u a t i o n , the f o l l o w i n g e q u a t i o n s were developed t o f i t the curves i n graphs #4 and 5. Fo r the c i s isomer; Log P = 1276.67 + 18.722 Log T - 50.7925 T F o r the t r a n s isomer, below 80°C Log P = 4590.97 + 47.2954 Log T - 131,9101 -T - 1 7 -F o r the t r a n s isomer, above 30°G Log P = 1545.15 + 15.6969 Log T - 42.7938 T CONCLUSION Two e q u a t i o n s were n e c e s s a r y to f i t the curve l o g P a g a i n s t JL f o r the t r a n s isomer because of the brea/K i n 7* the curve a t about 30 °C, As can be seen from graph #6, two stra i g h t l i n e f u n c t i o n s a r e o b t a i n e d f o r the t r a n s , whereas o n l y one f o r the c i s when we p l o t l o g l o g P a g a i n s t -3= . Wightman p o s t u l a t e d the p r o b a b i l i t y of the e x i s t e n c e o f more than two isomers f o r d e c a l i n , and C o r n e t t 0 found t h a t around 100°C , a change o c c u r r e d i n the t r a n s isomer. A l t h o u g h no c o n c l u s i v e evidence has y e t been p r e s e n t e d to prove the e x i s t e n c e o f more than two isomers f o r t h i s h y d r o c a r b o n , the i n t e r p r e t a t i o n of the r e s u l t s found i n t h i s r e s e a r c h s t r o n g l y f a v o u r s the f a c t t h a t an i n t e r n a l change occurs i n the t r a n s form a t about 80°G. On measuring the r e f r a c t i v e index o f the t r a n s sample used i n the vapour p r e s s u r e measurement, no change i n the v a l u e of t h i s p h y s i c a l c o n s t a n t c o u l d be f o u n d . S i n c e the c i s form i s g e n e r a l l y the more s t a b l e , i n s t e r e o i s o m e r s such as t h e s e , i t i s to be expected t h a t some change might occur i n the t r a n s , the u n s t a b l e form. 5 C o r n e t t , W.F. B.A. S c . T h e s i s U . B . O . (1935) - 18 -ACKNOWLEDGMENT The a u t h o r wishes to acknowledge w i t h t h a n k s , the h e l p f u l s u g g e s t i o n s g i v e n t o , and the s i n c e r e i n t e r e s t t a ken i n t h i s r e s e a r c h by Dr* W. F. Seyer, a s s o c i a t e p r o f e s s o r of c h e m i s t r y , U n i v e r s i t y of B r i t i s h Columbia. BIBLIOGRAPHY J . H. Armstrong and N. B e l l , B.A.Sc. T h e s i s , (1937) W.F. C o r n e t t , B.A.Sc. T h e s i s , (1935) Mohr, J . p r . Chem. 98, 315 (1918) , 103, 318 (1922) R. D. Walker, M.A.Sc. T h e s i s (1937) Wightman, J. Chem. S o c , 127, 1421 (1925) •' ;- APPENDIX. Heat of Vaporization of the Ois and Trans isomers Prom graph # 3 , i t i s seen that the vapour pressures of "both the eis and trans isomers are lin e a r functions of the temperature up to 40 degrees cent!grade.Thus we can safely apply the Olapeyron equation to determine the heat of vaporization f o r "both isomers. and substituting values of p and T i n t h i s equation,we arrive at the following values: Trans isomer: I - 7364 cal.per gm .mole,.between the range of 3 0 . 3 -» 29.4 deg.cent. Ois isomer: L - 5597 cal.per gnu mole,between the range of 19 .3 - 3 1 . 8 deg.cent.(av.value)• ._ __ oOo Using the integrated form of: d In p —/ I dT 

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