UBC Theses and Dissertations

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UBC Theses and Dissertations

The determination of physical properties of the cis and trans isomers of decahydronaphthalene Davenport, Charles Henry 1939

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o f the C i s and Trans Isomers of Decahyd ronaph tha l ene . " by C h a r l e s H. Davenpor t A T h e s i s Subm i t t ed i n P a r t i a l F u l f i l l m e n t of the Degree of Ma s t e r o f A p p l i e d S c i e n c e i n Chem ica l E n g i n e e r i n g The U n i v e r s i t y of B r i t i s h Co lumb ia 1938 - 1939. Table of Contents, Part 1 Page General Summary of Previous Investigation . 1 1. P u r i f i c a t i o n of Technical D e c a l i n ' U s e d . 4 2. The R e c t i f i c a t i o n Apparatus. .......................... ^ . . 5 'a) The Rectifying C o l u m n . 6 ;b) The Condensing Unit. 7 c ) The Receiving Unit 7 d) The Pressure Manometers............................. 7 3. The Separation of Gis and Trans Decalin................... 8 'a) The Experimental Prodecure. 8 ^b) The Experimental Results....,..'..................... 9 4. The P i n a l P u r i f i c a t i o n of Gis and Trans Decalin by Fractional C r y s t a l l i z a t i o n . . . . . . . . . . . . . . . . . . . . . . . . . . 14 (a) The Apparatus and Experimental Procedure............ 14 (b) Experimental Results for Gis Decalin,............... 15 (c) Experimental Results for Trans Decalin....- 16 5. Results of the 2nd Series of Rectifications and C r y s t a l l i z a t i o n s of Trans Decalin................... 17 Part 11 Section. a ;b Section a ;b Section I V a r i a t i Observati Observati II V a r i a t i Observati Observati m V a r i a t i Observati Observati on with Temperature of Density.....". 1 .,»-.„, 21 ons and Calculations for Cis Decalin.,..,,. 22 ons and Calculations for Trans Decalin,..., 24 on With Temperature of Viscosity........... 25 ons and Calculations for Cis Decalin...,,., 25 ons and Calculations for Trans Decalin..,.. 27 on With Temperature of Surface Tension 28 ons and Calculations for Cis Decalin....... 29 ons and Calculation?, for Trans Decalin. . . . , 30 P a r t 111 Page The M a t h e m a t i c a l T reatment of the E x p e r i m e n t a l R e s u l t s . . . . . . . 31 1. A S tudy of t he P l o t t e d R e s u l t s f o r the P h y s i c a l p r o p e r t i e s 2. A Study of the P l o t t e d R e s u l t s for t he P h y s i c a l P r o p e r t i e s 3 . The V a r i a t i o n w i t h Temperature of D e n s i t y . . . 35 4 . The V a r i a t i o n w i t h Temperature of Su r f a c e T e n s i o n . 38 5„ D e t e r m i n a t i o n o f P a r a cho r s 41 6. The T o t a l and M o l e c u l a r S u r f a c e E n e r g i e s 45 7. The L a t e n t Hea ts o f V a p o r i z a t i o n and F u s i o n . . . . . . . . . . . . . . . 47 8 . The V a r i a t i o n w i t h Temperature of V i s c o s i t y 49 P a r t IV I n f o r m a t i o n Ob ta i ned f rom F u r t h e r R e c t i f i c a t i o n and C r y s t a l l i z a t i o n 52 1. R e s u l t s o f the R e c t i f i c a t i o n of C i s and Trans D e c a l i n 52 2. The F i n a l P u r i f i c a t i o n of C i s and T rans - "Deca l i 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 57 ( a )Appa ra tu s and E x p e r i m e n t a l P ro cedu re 57 ( b J E x p e r i m e n t a l R e s u l t s f o r C i s D e c a l i n . 57 ( c J E xpe r imen t a l R e s u l t s f o r Trans D e c a l i n . . . . 58 P a r t V A Study o f the E f f e c t of Heat on the Decompos i t i on of C i s and Trans D e c a l i n 60 (a) The E x p e r i m e n t a l P ro cedu re 61 (b) R e s u l t s o f the Heat T r e a tmen t . . 63 Table of Diagrams 1. Graph Showing Volts Across Heating Coils for Adiabatic Operation of the Rectifying Column ..... 6 2. Apparatus for Vacuum, Fractional D i s t i l l a t i o n of Decalin, 7 3. Graph Showing Variation of Index of Refraction with Composition. 9 4. Apparatus f o r P u r i f i c a t i o n by Recrystallization of the Isomers of Decalin.................................. 14 5. Apparatus for Determination of Density, V i s c o s i t y and Surface Tension of the Isomers of Decalin........... 21 6„ Graph Showing Variation with Temperature of Surface" """ Tension, Density and Viscos i t y of Gis Decalin....... 31 7 . Graph Showing Variation with Temperature of Surface Tensions Density and Viscos i t y of Trans Decalin..... 34 3. Graph Showing Application of Law of C a i l l e t e t and llathias to Isomers of Decalin. , . . 37 9. Graph Showing Ferguson's Equation Applied to the Isomers of Decalin.................................. . 42 10. Graph Showing Variation with Temperature of Molecular Surface Energy of Isomers of Decalin..,......,.'.,... 47 11. Graph Showing Batschinski's Equation Applied to the Isomers of Decalin. 51 { 1. P a r t l._ D u r i n g t he l a s t few yea r s c o n s i d e r a b l e r e s e a r c h has been done on the h yd r o c a r bon , decahyd ronaph tha l ene , ( C i 6 ^ 1 8 - - a b b r e v i a t e d e c a l i n ) , as i t has been e s t a b l i s h e d t h a t t h i s compound e x i s t s i n a t l e a s t two i s o m e r i c f o rms ; the c i s and the t r a n s . The g r ea t "drawback to a l l i n v e s t i g a t i o n i n t h i s f i e l d r e g a r d i n g the i s o m e r i c s t r u c t u r e l i e s i n the f a c t t h a t the two forms a r e v e r y d i f f i c u l t to s epa r a t e f r om one ano the r i n the pure s t a t e . The s e p a r a t i o n appears to be a l l the more c o m p l i c a t e d when we c o n s i d e r t h a t t h e r e i s a lways a p o s s i b i l i t y of p a r t i a l c o n v e r s i o n of one fo rm to the o t h e r , and a l s o t h a t t h e r e i s a p o s s i b i l i t y of t h e r e b e i n g more t h an two i somers p r e s e n t . S i n c e the u l t i m a t e a im of the f o l l o w i n g r e s e a r c h i s to de te rm ine the v a r i a t i o n w i t h tempera tu re of t h r e e of the p h y s i c a l p r o p e r t i e s o f the c i s and t r a n s , a b r i e f summary o f p r e v i o u s i n v e s t i g a t i o n i n t h i s f i e l d w i l l now be p r e s e n t e d . •• The f i r s t p r e d i c t i o n of the e x i s t e n c e o f i somers o f d e c a l i n was t h a t of M o h r 1 , who p o s t u l a t e d the p o s s i b i l i t y of two s t a b l e f o rms . The e x i s t e n c e o f t h e s e , the c i s and t r a n s , has now been d e f i n i t e l y e s t a b l i s h e d , bu t no agreement has y e t been reached by d i f f e r e n t i n v e s t i g a t o r s as to the p h y s i c a l and chem i ca l p r o p e r t i e s 2 of each . A s h o r t t ime l a t e r , Wightman showed t h a t f i v e i somers were p o s s i b l e f o r d e c a l i n . I n 1924, r e s e a r c h on the s u b j e c t was advanced by W i l l s t a t t e r 3 and S e i t z who r e p o r t e d t h a t they had p repa red the c i s fo rm i n 1. Mohr, J . •, pfy. Chem., 98, 315, (1918) 103 , 316, (1922) 2. Wightman, J . Chem. S o c . , 1 2 7 , 1421 ( 1925 ) . 3 . W i l l s t a t t e r and S e i t z , B e r i c h t e , 57B . , 683-4 ( 1924 ) . s i x d i f f e r e n t ways a t t empera tu res r a n g i n g f r om 20-80°G. T h e i r p r oduc t i n a l l c a ses d i d no t show v a r i a t i o n s g r e a t e r t han a few , u n i t s i n t he 4 t h d e c ima l p l a c e f o r e i t h e r the d e n s i t i e s or r e f r a c  t i v e i n d i c e s . I n the same y e a r , N . 0 . Z e l i n s k y 1 announced t h a t he had i s o l a t e d a 3 rd i somer ; t h a t i s , one d i s t i n c t f rom e i t h e r c i s or t r a n s . F u r t h e r r e s e a r c h by Z e l i n s k y and M. B. Tu rova - P o l l o k 1 i n 1925, showed t h a t a t 100°C. i n the p resence of a c a t a l y s t of a luminum b rom ide , c i s c o u l d be t rans fo rmed i n t o the t r a n s f o rm . A l s o they c l a imed t h a t o t he r i somers of d e c a l i n were formed d u r i n g the t r a n s f o r m a t i o n p r o c e s s . As p r e v i o u s l y s t a t e d , d i f f e r e n t i n v e s t i g a t o r s do not agree as to the p h y s i c a l and chem i c a l p r o p e r t i e s o f the i s ome r s . F o r d e n s i t y , i ndex o f r e f r a c t i o n and f r e e z i n g p o i n t , W . Hucke l p r e s en t s the f o l l o w i n g v a l u e s J Trans d e c a l i n d | ° » 0 8695 ,_20 i r D . s 1.46958 F , P . B ^36°0 C i s d e c a l i n &2 * .8940 2 0 % " 1.47950 P . P . * -51°C A c c o r d i n g to Hucke l . , He r z ° appears to have been the f i r s t to a t tempt t he s e p a r a t i o n of t h e i somers by f r a c t i o n a l d i s t i l l a t i o n . A l t h ough Herz was u n s u c c e s s f u l , h i s methods sugges ted p o s s i b i l i t i e s wh i c h were l a t e r r e a l i z e d i n the r e s e a r c h work c a r r i e d on a t the U n i v e r s i t y of B r i t i s h Co l umb i a . A t t h i s U n i v e r s i t y , the f i r s t work on t h i s compound was c a r r i e d on by L. M. K i r k 4 , who, u s i n g d e c a l i n p repa red by 1. Z e l i n s k y , N. 0 . and T u r o v a - P o l l a k , M. B . , B e r i c h t e , 58B . , 1292-98 2. H u c k e l , W . , Anna l en der Chemie; 441 , 1 (1925) (1925) , 3 . He r z , Z . P h y s i c s , Chem. 101, 269 ( 1922 ) . 4 . K i r k , L. M . , B. A . S c . , T he s i s (1935) 3. on D. M a n l e y 1 by r e d u c t i o n of t e t r a l i n , o b t a i n ed a p a r t i a l s e p a r a t i o n o f the c i s and t r a n s i s ome r s . The method used was r e c t i f i c a t i o n a t 100 mms. p r e s s u r e , bu t i t was l a t e r thought t h a t i f t he r e c t i f i c a t i o n were a t 10 mms. p r e s s u r e , a b e t t e r s e p a r a t i wou ld be o b t a i n ed s i n c e the d i f f e r e n c e i n b o i l i n g p o i n t of the two i somers wou ld be much i n c r e a s e d . A l s o i t was r e a l i z e d t h a t a t the h i g h e r p r e s s u r e s , the h i g h e r t empera tu res se t up i n the co lumn, a re ap t to b r i n g about de compos i t i o n o r p o s s i b l y r e a r r ange ment i n s i d e the d e c a l i n m o l e c u l e . K i r k ' s work was supp lemented i n the same yea r by t h a t o f W. P. C o r n e t t who c a r r i e d out t e s t s i n v a r i o u s m i x t u r e s of the c i s and t r a n s i somers a t t empe ra tu re s of 20°C and 100°C, w i t h ou t the p re sence of a c a t a l y s t . T h i s work i n d i c a t e d w i t h ou t doubt t h a t c i s was changed i n t o t r a n s , the r a t e of change b e i n g much g r e a t e r a t 100°C t han a t 20°C. However, no c o n c l u s i v e ev idence was o b t a i n ed f o r the r e v e r s e a c t i o n , the chang ing of t r a n s i n t o CIS, The i d e a c o n c e r n i n g t he e f f e c t of l ower p r e s s u r e was now expe r imen ted w i t h by R. D. W a l k e r 3 i n c o n j u n c t i o n w i t h P r o f . W. P. S e y e r 4 , T h e i r method c o n s i s t e d i n r e c t i f i c a t i o n a t 10 rams, p r e s s u r e , of t e c h n i c a l d e c a l i n . I n a l l , t en r e c t i f i c a t i o n s were made. S e l e c t e d f r a c t i o n s o f h i g h pe r cen tage c i s and t r a n s were then r e c r y s t a l l i z e d u n t i l no f u r t h e r change i n f r e e z i n g p o i n t « • • « • 1, Manley, U., B.A. Sc,, T h e s i s "(1934) 2. C o r n e t t , W. P., B. A. Sc., T h e s i s (1935) 3, Walker, R. D . , Iff. A. Sc., T h e s i s (1937)' ~ ; 4. S.eyer, W. P., Assoc. P r o f , i n Ghem. Eng., U n i v e r s i t y of B. C. 4. c o u l d "be d e t e c t e d , the r e s u l t of t h i s b e i n g about 150 c . c . of each i somer i n what was thought to be a f a i r l y h i g h s t a t e of p u r i t y . .The v a l u e s t hey o b t a i n ed f o r the p h y s i c a l c on s t an t s a r e t a b u l a t e d thuss C i s D e c a l i n Trans D e c a l i n F r e e z i n g P o i n t (°C) -43.19-0.2 —31.29- 0 O2 D e n s i t y (Dg 0 ) .8963 .8699. Index' of R e f r a c t i o n (N^Q) 1.48113 1.46968 D e t e r m i n a t i o n s o f f r e e z i n g p o i n t s were made' f o r v a r i o u s m i x t u r e s of the two i s ome r s , the r e s u l t s i n d i c a t i n g t h a t the e u t e c t i c t empe ra tu re l i e s between - 60° and - 70 °C . A l s o f o r these s ame 'm i x t u r e s j measurements were made o f \ d e n s i t y and r e f r a c t i v e i n d e x . ' • The above has been a p r e s e n t a t i o n of the main a v a i l a b l e da ta on these i somers up to the p r e s en t t ime . The f o l l o w i n g w i l l show • how we o b t a i n e d s u b s t a n t i a l amounts of each pure i somer by f o l l o w i n g the Wa l k e r - S e y e r method, and f i n a l l y my d e t e r m i n a t i o n of d e n s i t y , v i s c o s i t y and s u r f a c e t e n s i o n over a t empera tu re r ange . 1. P u r i f i c a t i o n o f the T e c h n i c a l D e c a l i n _ U s e d . The sample of d e c a l i n r e c e i v e d f rom the Eastman Kodak L a b o r a t o r i e s was y e l l o w - o r a n g e i n c o l o r , and c on t a i n ed v a r i o u s i m p u r i t i e s of an a r oma t i c n a t u r e . To remove these o b j e c t i o n a b l e components, such a method as the f o l l o w i n g was u s ed . 5 9 About 2 l i t r e s o f sample were measured out and shaken t h o r o u g h l y i n the c o l d w i t h 400 c . c . of c on cen t r a t ed s u l p h u r i c a c i d . A f t e r a l l o w i n g the l a y e r s to s e p a r a t e , the b l a c k a c i d l a y e r was drawn o f f and d i s c a r d e d ; t he upper l a y e r was c o l l e c t e d and s u b j e c t e d to a second, s i m i l a r t r e a tmen t . A t o t a l of t h r e e such -•• a c i d t r e a tmen t s was r e q u i r e d b e f o r e the sample appeared p r a c t i c a l l y c o l o r l e s s . To remove a c i d f rom the sample , i t was now shaken w i t h 100 c . c . o f 10% sodium ca rbona te s o l u t i o n , a p e r s i s t e n t m i l k i n e s s r ema in i ng i n b o t h l a y e r s , even a f t e r s t a n d i n g o v e r n i g h t . The l a y e r s were s e p a r a t e d , and the upper l a y e r was now shaken w i t h 200 c . c . of 3% sodium h y d r o x i d e s o l u t i o n . T h i s a ga i n produced m i l k i n e s s , but gave w e l l - d e f i n e d l a y e r s . A f t e r s e p a r a t i n g a g a i n , the bot tom l a y e r was t e s t e d w i t h 2 drops of p h e n o l p h t h a l e i n , the r e s u l t i n g p i n k c o l o r showing t h a t a l l a c i d had been d e s t r o y e d . l ow i n o rde r to r ende r the sample n e u t r a l , i t was washed seven t imes w i t h 200 c . c . p o r t i o n s of w a t e r . S l i g h t m i l k i n e s s s t i l l p e r s i s t e d a f t e r t h i s t r e a tmen t . The f i n a l s t e p was t o remove a l l t r a c e s of wate r and m i l k i n e s s . T h i s was a c comp l i s hed by f i r s t , f i l t e r i n g t h rough a s i n g l e sheet of heavy f i l t e r paper to remove the b u l k of the wa t e r , and second, by f i l t e r i n g t h r ough a doub le sheet c o n t a i n i n g anhydrous c a l c i um c h l o r i d e . Our sample of d e c a l i n now appeared as a c o l o r l e s s l i q u i d . 2. The R e c t i f i c a t i o n A p p a r a t u s . The appa ra tu s used f o r the r e c t i f i c a t i o n s was e s s e n t i a l l y the same as t h a t employed by R. D. Wa lker and P r o f . W. P. Seye r . 6, The c h i e f improvements c o n s i s t e d i n the f o l l o w i n g j (a ) the use of e l e c t r i c h e a t e r s i n p l a c e of gas bu rne r s f o r h e a t i n g the co lumn. Th i s reduced the danger of h e a t i n g su rge s , w i t h the r e s u l t t h a t we c o u l d he f a i r l y s a f e i n i n t e r p r e t i n g ... *, t empera tu re changes a t t he t op of the column as b e i n g due to changes i n the c ompos i t i o n of the l i q u i d d i s t i l l i n g o ve r . Hence improved s e p a r a t i o n o f f r a c t i o n s c o u l d be e xpec t ed . (b) the mercury manometer was r e c o n s t r u c t e d i n such a manner t h a t an a b s o l u t e vacuum cou l d be ma i n t a i n ed a t a l l t imes above the mercury i n the c l o s e d t ube . ( c ) when i n o p e r a t i o n , the appa ra tu s was run c o n t i n u o u s l y day and n i g h t u n t i l t he c o m p l e t i o n of the r e c t i f i c a t i o n of the d e c a l i n cha rge . The f o l l o w i n g d e s c r i p t i o n , a l o ng w i t h the d i ag ram, g i v e s the d e t a i l s o f the appa ra tu s u s e d . (a ) The R e c t i f y i n g Co l umn- -Th i s c o n s i s t e d o f a g l a s s t ube , 1 i n c h i n d i ame te r and 95 i n che s l o n g , w i t h a. 3000 c . c . g l a s s bu l b b lown on i t s l ower end. A s m a l l i n l e t tube was a t t a c hed to the b u l b . Ex cep t f o r the h e a t i n g s u r f a c e a t the bot tom and f o r a s m a l l peep h o l e i n the; s i d e of the b u l b , b o t h column and bu l b were c omp l e t e l y l agged w i t h a s b e s t o s . A l s o , i n o rde r to compensate f o r hea t l o s s e s to the a tmosphere , two h e a t i n g c o i l s of n ichrome w i r e were wound i n p a r a l l e l about the column nex t to the g l a s s , one c o i l c o v e r i n g the t o p , and the o the r the bo t tom h a l f o f the co lumn. The accompany ing g r aph , r ep roduced f rom the r e s u l t s o f • • •* R. D. Wa lke r and P r o f . W. P. Seye r , shows the v o l t s r e q u i r e d a c r o s s H 1 j • i ' i Gr iph Showinq Volfe across \ leafing Coils •for Aciiatx Rec • • • ; ' • • • < ; itic Operator Jrfyina Colurr i of Hie m • . .. | 4 . 70 1 | o f C olu mn  (°  lop  o f I nfe rior  5 - e • '• ' . ,M(| 'I i E ffe ren ce be tw  s C ~ \— 1 ' , . • - . . „• : i em per afu re Dj 1 , 1 1 • • •  • ••: If 10 1 Volls aero ss Heating G ) 2 ills 0 2 1 i -•• :' -. • • } I. • •• i j ! j i 7 . the doub le co i . l i n o rde r to m a i n t a i n a d i a b a t i c o p e r a t i o n . The i n t e r i o r o f the col l l^was packed w i t h No . 18 g a l v a n i z e d - i r o n j a c k c h a i n . (b) The Condens ing Un i t -~BIown on to the s i d e of the column a few i n c he s f rom the t o p , was the condens i ng u n i t . T h i s was made up of two r e f l u x condensers j o i n e d i n p a r a l l e l , and l e a d i n g f r om the f o o t o f t h i s c omb ina t i on was a c a p i l l a r y tube th rough . • » wh i ch the p roduc t was t aken o f f . A l s o , a thermometer was i n s e r t e d i n t o the top o f the co lumn, e x t end i ng down as f a r as the o u t l e t tube to t he condense r s . • . . ( c ) The R e c e i v i n g U n i t - - T h i s a ppa r a t u s , as the d iagram shows, was made up of f i v e r e c e i v i n g b u l b s , a l l j o i n e d s e p a r a t e l y to t he bo t tom of a g l a s s c a s i n g . Runn ing t h r ough the c e n t r e o f t h i s c a s i n g and f u s e d on to i t a t t he t o p , was the p roduc t tube f rom the condense r s , the l ower end of the tube p o s s e s s i n g a sma l l d i s c h a r g e spou t . The spout c o u l d be r o t a t e d f rom one r e c e i v i n g , b u l b to t he nex t by mov ing an e l e c t r omagne t o u t s i d e t he g l a s s c a s i n g , t he r e s u l t b e i n g t h a t the magnet a t t r a c t e d s m a l l i r o n ba r s a t t a c h e d to the d i s c h a r g e t ube , the whole then moving c i r c u l a r l y on a p i v o t . To make su re t h a t d u r i n g d i s t i l l a t i o n t he d i s c h a r g e spout wou ld no t wander out o f p o s i t i o n when once- se t f o r a p a r t i c u l a r b u l b , a permanent magnet was s t r apped to the s i d e of t he c a s i n g . (d) The P r e s s u r e Manometers - -A mercury manometer f o r measu r i ng a b s o l u t e p r e s s u r e i n t he appa r a t u s , and a d i f f e r e n t i a l s u l p h u r i c a c i d manometer f o r d e t e c t i n g s m a l l f l u c t u a t i o n s i n 8. p r e s s u r e , were employed. The l a t t e r was 7.3 t imes as s e n s i t i v e as the f o rme r . The mercu ry manometer was on l y used a t the - beg i nn i ng , of a r un u n t i l p r e s s u r e e q u i l i b r i u m was e s t ab l i s hed - ; then the s t opcock on one l i n k of the a c i d manometer was c l o s e d , and f u t u r e p r e s s u r e changes were obse rved on t h i s s c a l e . 3 , The S e p a r a t i o n o f C i s and T rans D e c a l i n . (a ) The E x p e r i m e n t a l P r o c edu r e - - A s p r e v i o u s l y s t a t e d , each r e c t i f i c a t i o n was made c on t i n uou s ; t h a t i s , f o r each b a t c h of d e c a l i n used i n t he column b u l b , the r e c t i f i c a t i o n was c a r r i e d on day and n i g h t u n t i l a l l bu t a l i t t l e l i q u i d r e s i d u e remained i n the b u l b . Read ings were made e ve r y , hou r of vapour t empera tu re , room t empe ra t u r e , condenser wa te r t empe ra tu re , and a l s o of p r e s s u r e . I n t h i s way we were a b l e to m a i n t a i n a d i a b a t i c o p e r a t i o n of the co lumn, and o b t a i n good s e p a r a t i o n of the v a r i o u s f r a c t i o n s . Moreove r , i t enab led us to keep good check on the p r e s s u r e (wh i ch was kep t as c l o s e as p o s s i b l e to 10 mms. o f me r cu r y ) , bu t l i t t l e d i f f i c u l t y was e xpe r i e n c ed h e r e , f o r once the l e v e l s had come to e q u i l i b r i u m , they u s u a l l y wou ld rema in cons t an t f o r hou r s a t a t ime . S l i g h t v a r i a t i o n s i n p r e s s u r e were c o r r e c t e d f o r by a d j u s t i n g a s t op co ck wh i ch connec ted the appa ra tus t h rough a d r y i n g tube to the a tmosphere . The f o u r W inches t e r b o t t l e s as shown i n the d i ag ram and h a v i n g a t o t a l c a p a c i t y of 10 l i t r e s , s e r ved as p r e s s u r e e q u a l i z e r s , - I t may he re be ment ioned t h a t the r e f l u x r a t i o i n the appa ra tu s c o u l d not be measured bu t c o u l d o n l y be judged by o b s e r v a t i o n o f the amount of vapour c ondens i ng . I t was found that the number of drops per minute overflow through the c a p i l l a r y and discharge tubes had a tendency to decrease s l i g h t l y a s , t h e ' r e c t i f i c a t i o n proceeded. However, the reflux ratio was kept as constant as possible by controlling the temperatures and the amounts of condenser water used. The condenser water was pumped from a large constant-temperature bath. ' - •(b)'The Experimental Results--In the following tabulations w i l l be found the results of our four r e c t i f i c a t i o n s . The f i r s t two, i t w i l l be noted, were run using our washed decalin, the purpose being to obtain s u f f i c i e n t quantities of the particular fractions which were high in cis or trans content. Then, using these high percentage fractions, we combined them in the t h i r d and fourth r e c t i f i c a t i o n s respectively, i n order to obtain our f i n a l high cis and trans fractions. The r e f r a c t i v e index at 20°C. and for D-sodium l i g h t was recorded for each f r a c t i o n , use being made of a P u l f r i c h refractometer. Then, employing the refractive indices of pure cis and trans as determined by R. D. Walker and W. E. Seyer and assuming a linear relationship between the indices and composition, the accompanying graph was constructed. Prom this graph, the approximate composition of each fraction could be read off. - ' Other data and general information concerning the r e c t i f i c a t i o n s , appears i n the following results. Characteristics of Charge; (a) 2000 c.c. of washed decalin (Eastman Kodak) (b) D| 0 = .8920 (c) = 1.47965 (d) approximate composition - 87% cis Bulb 1 Bulb 2 Bulb 3 Bulb 4 Bulb 5 ' Boi l i n g Point of Fraction (°C) 60.8-64.0 63.9-64.2: 64.2-67.8 67.8-69.2 69.2-63.0 Volume of Fraction (c.c.) 121 - 332 743 .352 290 Time for Fraction (hrs.) 3.75 12.0 34,0 20.5 15.5 Rate of Fractionation (c.c./hr,) 32.3 27.7 21.9 17:. 2 : l$ i 7 ; -Index of Refraction -1 : " :(^| 0) 1.47081 1.47170 1.47975 1.48113 1.48229 Approximate Composition {% of cis) . ' 9 , . 18 88 99 >100 F i n a l residue i n column bulb = 40 c.c 0 Hence t o t a l loss during r e c t i f i c a t i o n **B JL 2 2 o 9 o The fact that the f i r s t fractions (that i s , those with the lower b o i l i n g points) were high in trans content, indicated that of the two isomers, trans has the lower b o i l i n g point. The analysis of Bulb 5 shows the presence of impurities of high b o i l i n g point, they being such that their indices of refraction had considerable influence on the index of pure c i s . Evidently, these impurities were not affected by the i n i t i a l washing treatment. 11 . Oc tobe r 2 3 - - 0 c t o b e r S8 T 1937. R e c t i f i c a t i o n No. 2 C h a r a c t e r i s t i c s of ChargR: (a)^ 2025 c . c . of washed d e c a l i n (Eastman Kodak) (b) D 20 .8920 ( c ) « 1.47965 (d) app rox ima te c ompo s i t i o n = Qn% c i s Bu l b 1 Bu l b 2 B o i l i n g P o i n t o f F r a c t i o n ( °C) Volume of F r a c t i o n .57. 0 -62 ,4 \A f^J 62 . 4 - 64 , 4 X) U J_ u o 64 . 4 - 67 . 4 -tSulb 4 6 7 . 4 - 7 3 . 2 Bu l b 5 ( c . c . ) Time f o r F r a c t i o n 225 - 240 745 " 403 ( h r s . ) , Ra te o f F r a c t i o n a t i o n ( c ; c . / h r . ) Index o f R e f r a c t i o n Approx imate Compos i t i o n {% of C i s ) 10.-5 14 .5 56 .0 30 .0 - - - - - - - 21.4 '"16.6 13 ,3 13 ,4 1.47076 8 1.47455 ", 43 1.48098 97 1.48283 > 100 — [ F i n a l r e s i d u e i n column b u l b a 97 c . c . Hence t o t a l l o s s d u r i n g r e c t i f i c a t i o n = 315 c . c . A l t h o u g h the same t ype o f d e c a l i n was used f o r t h i s r e c t i f i c a t i o n as was used f o r t h e f i r s t , i t was found t h i s t ime t h a t f o u r main f r a c t i o n s , i n s t e a d of f i v e , c o u l d be o b t a i n e d . T h i s was p r obab l y due to b e t t e r c o n t r o l and s e p a r a t i o n d u r i n g t h i s r e c t i f i c a t i o n , s i n c e we used a s m a l l e r r a t e of p roduc t d i s c h a r g e . The h i g h b o i l i n g p o i n t i m p u r i t i e s a g a i n appear i n our l a s t f r a c t i o n . C h a r a c t e r i s t i c s o f Charge ; (a) 1725 c , c . o f h i g h c i s d e c a l i n , c omp r i s i n g b u l b s 4 and 5 o f R e c t i f i c a t i o n No . 1 and b u l b s 3 and 4 of R e c t i f i  c a t i o n No. 2. (b) - 1.48166 ( c ) app rox ima te c ompo s i t i o n s >100% c i s Bu l b 1 Bu l b 2 Bu l b 3 Bu l b 4 Bu l b "W ' ' . B o i l i n g P o i n t o f •' • -—:— F r a c t i o n ( ° c ) Volume of F r a c t i o n 6 0 . 4 - 6 3 . 5 63 . 5 - 66 . 7 64 . 5 - 67 . 8 •67 .8-66 .9 66 . 9 - 64 . 6 ( c . c . ) Time f o r F r a c t i o n 162 423 540 203 114 ( h r s . ) Ra te o f F r a c t i o n a t i o n 18 .0 42 . 0 38 .5 13 .5 13 .0 ( c . c . / h r . ) Index o f R e f r a c t i o n 9 .0 10 .0 14 .0 15.. 0, 8 .8 j Appr ox imat %UCompo s i t i o n 1.48024 1.48108 1.48113 1.48118 1.48118 ; {% o f c i s ) 92 .5 100 100 100 100 F i n a l r e s i d u e i n column bu l b = 95 c . c . Hence t o t a l l o s s d u r i n g r e c t i f i c a t i o n s 188 c . c . Bu l b s 3,4 and 5 were o b t a i n ed w i t h the r e c t i f i c a t i o n p r e s s u r e • s l i g h t l y l e s s than t h a t used f o r b u l b s 1 and 2. Our h i g h c i s d e c a l i n was now c on c en t r a t e d i n the l a s t f o u r b u l b s , the c h i e f i m p u r i t i e s be ing i n the b u l b 1. B e f o r e p r o c e e d i n g w i t h the t r a n s , the column was now washed t h o r ough l y by r e f l u x i n g i n i t f o r 7 hours a charge of d e c a l i n wh i ch .had an app rox ima te c o m p o s i t i o n o f 37% t r a n s . T h i s wash ing charge was - made up of t h r e e f r a c t i o n s ob t a i n ed f rom the R. B. Wa lker - W. F. Seyer r e c t i f i c a t i o n s . 13. R e c t i f i c a t i o n JNb. 4 Nov.emberT6 V - November 19, 193'7!, C h a r a c t e r i s t i c s o f Cha rge : • •.. . (a) 1490 c . c . o f h i g h t r a n s d e c a l i n , c omp r i s i n g b u l b s 1 and- * 2 o f R e c t i f i c a t i o n No. 1; b u l b 1 of R e c t i f i c a t i o n No. -2; \ and 3 .washed, h i g h t r a n s f r a c t i o n s f rom the R. D. Wa lke r - ¥ . F. Seyer r e c t i f i c a t i o n s . (b) N^ Q = 1.46987 ( c ) app rox ima te c o m p o s i t i o n - 100% t r a n s . B o i l i n g P o i n t o f F r a c t i o n (°C) Volume o f F r a c t i o n ( c . c . ) Time f o r F r a c t i o n ( h r s . ) Ra te o f F r a c t i o n a t i o n . fc..c./hr.) Index of R e f r a c t i o n Approx imate Compos i t i o n {% t r a n s ) F i n a l r e s i d u e i n column b u l b * 165 c . c . Hence t o t a l l o s s d u r i n g r e c t i f i c a t i o n = 29 c . c . From the i ndex g r aph , i t appears t h a t the i ndex f o r the f r a c t i o n i n b u l b 1 i s v e r y much s m a l l e r than the accep ted index f o r pure t r a n s . Thus b u l b 1 must have c on t a i n ed a g r ea t dea l , o f some T o w - b o i l i n g i n p u r i t y . Bu l b 1 5 0 . 5 - 6 4 . 0 •* Bu lb: 2 6 4 , 0 - 6 0 . 2 Bu l b 3 60. 2^59.5 Bu l b 4 59,5-»60.9 BuTb~5~^~"! : 60 . 9 - 61 . 8 230 490 240 195 141 f 8 ,0 ' 23 .5 13 « 5 11 ,5 • ij ; 8 ' ? . 5 • 1 28.7 : . 20 . 9 : 17.8 17 .0 -16.6..' .| 1.46192 1.46918 1.46958 : 1,46968 1.47100 >100 >100 100' 100 89 i 4 . The F i n a l P u r i f i c a t i o n of Cis and Trans Decalin__by_ ij . , _ - p r a c - t j o n a i c r y s t a l l i z a t i o n . jj This method of p u r i f i c a t i o n i s based on the formation of a . |j eutectic When a mixture of c i s and trans decalin i s frozen. Thus, u i f we have decalin containing a certain percentage of trans, and » we cool i t slowly, there w i l l be a certain temperature at which • Jj trans crystals commence to separate out. This separation of trans j- crystals w i l l continue with further cooling u n t i l we reach the jj eutectic temperature, at which point a l l remaining l i q u i d w i l l freeze J to give the eutectic mixture. Since the. eutectic mixture w i l l be of no use to us, then, i n order to obtain the high trans by this method,, i t w i l l be necessary to stop cooling before reaching the eutectic temperature and to pour off the remaining l i q u i d . T h e < * trans crystals obtained, along with a l i t t l e of the clinging liquid**; w i l l consequently be of higher trans content than the o r i g i n a l decalin ^.mixture. If we. repeat the process now with the crystal mixture - obtained, we w i l l remove a l i t t l e more l i q u i d , and f i n a l l y , after- • t- . doing many of these c r y s t a l l i z a t i o n s , w i l l arrive at the stage where the removal of a portion of l i q u i d w i l l not lower the temperature at which crystals f i r s t separate out. This condition w i l l then indicate that the l i q u i d i s pure, and the constant temperature w i l l be the true freezing point. (a) The Apparatus and Experimental Procedure--The accompanying diagram shows the set-up of apparatus employed, and very l i t t l e additional explanation i s required. It may be mentioned that a v e r t i c a l line-image was formed on the graduated 1 glass scale, and when ,the bridge was balanced, this l i n e was at the centre of the 15. scale. Resistance readings could be converted to temperatures by application of Callendar's formulae. The l i q u i d to be pu r i f i e d was placed in a large glass tube i n the Dewar, and was cooled by the surrounding medium of solid, carbon dioxide. During the f i r s t few c r y s t a l l i z a t i o n s , mechanical s t i r r i n g was employed, but this had the disadvantage of leaving- • a thick crust of crystals around the periphery of the Dewar, with the result that the heat transfer was lowered and the thermometer could not be kept surrounded with l i q u i d at a l l times. Hence, toward the end of pu r i f i c a t i o n s , hand s t i r r i n g was employed for each run. In carrying through a c r y s t a l l i z a t i o n , the l i q u i d was cooled slowly u n t i l a constancy was obtained in the resistance readings,• > .this corresponded to cis (or trans, as the case may be) c r y s t a l l i z i n g out, and the times of constancy could be used for judging r e l a t i v e purities of successive c r y s t a l l i z a t i o n s . When pure, there was no eutectic, and the temperature was constant for the greatest time. When the temperature started to drop again, i t was in each case observed for several minutes, and then the remaining l i q u i d was . decanted off. Supercooling was one of the chief d i f f i c u l t i e s experienced. We.found that this could be minimized usually by vigorous hand s t i r r i n g and by using a slow rate of heat transfer; when these methods f a i l e d , seeding was always successful. .(b) Experimental Results for Cis Decalin--The fractions selected for the p u r i f i c a t i o n were bulbs 2,3,4 and 5 of Re c t i f i c a t i o n No. 3. It required about twenty separate c r y s t a l l i z a t i o n s to obtain 16. the pure isomer, the f i n a l volumetric y i e l d being 313 c.c. An appreciable amount of water was absorbed from the atmosphere during the' p u r i f i c a t i o n , but this was easily removed by treat ment with metallic sodium, and then by f i l t r a t i o n . In order to give a low rate of heat transfer i n the f i n a l stages, the l i q u i d was placed in a large glass tube possessing a hollow wall (resembling a Dewar), the hollow space containing a i r . Also, at the same time, the dry ice medium was replaced by one of methyl alcohol containing.dry ice, The temperature of this medium was maintained at -55°C., and was measured with a pentane thermometer. For cis decalin our f i n a l r e s u l t i s : F.P. s - 4 3 . 2 6 t . 04 °C. and s 1 . 48113 R. D c Walker and W. F. Sever gave. F . P . = - 4 3 . 1 9 i .2 °C. and 1^0 = 1 . 48113 (c) Experimental Results for Trans Decalin--The p u r i f i c a t i o n of this isomer gave considerable trouble. From a large number of c r y s t a l l i z a t i o n s based, f i r s t , on bulb 2 , and second, on bulbs 3 and 4 , a l l of R e c t i f i c a t i o n No. 4 , i t was discovered that no constancy in freezing point could be obtained. This fact appeared to indicate the presence of some impurity whose index of re f r a c t i o n , freezing point and b o i l i n g point, are very close to that of trans decalin. The presence of such a substance appears a l l the more remarkable- when we consider that i t did "• not give trouble at this stage in the research of R. D. Walker • - and W. IP. Seyer. Since these investigators used unwashed decalin in their r e c t i f i c a t i o n s , i t seems possible that the presence of other impurities (that are removed by washing) must i n some way help to cause the removal of this Impurity encountered i n our high trans fract i o n s . To avoid further loss of time, we considered i t advisable to fractionate a quantity of unwashed decalin. The results obtained are now presented. 5. Results of the 2nd Series of Rectifications, and  Cry s t a l l i z a t i o n s of Trans Decalin. (Over) 18. ; R e c t i f i e a t i on N o ^ _ l _ l a l January 6—January 8, 1938. Characteristics of Charge; (a) 2000 c.c. of unwashed decalin (Eastman Kodak) (h) D (c) W 20 •D 20 s .8890 s 1.47829 (d) approximate: composition s.,23% trans Boi l i n g Point of * Fraction (°C) Volume of Fraction (c,c.) Time for Fraction (hrs.) Rate of Fractionation (c.c./hr,) Index of Refraction ( * 2 0 } Approximate Composition {% trans) Bulh 1 70.7-72.2 288 17.0 16.9 1.46938 >100 Bulh 2 72.2-69.0 135 9.0 15 .0 1.46958 100 Bulh 3 69.0-68.0 140 8.0 17.5 . 1.46983 100 Bulh 4 68.0-69.9 173 12.0 14.4 1.47150 84 Bulh-5 69.9-73.1 , 92 8.0 11.5 1.47760 31 ' The pressure was s l i g h t l y greater in this r e c t i f i c a t i o n than- in previous ones. It w i l l he noted from the. compositions obtained that very good r e c t i f i c a t i o n was accomplished. This was due to . our maintenance of a slow rate of discharge, and also to the fact that we d i s t i l l e d over less than half of the bulb charge, since we were not concerned now with the cis isomer (which has the higher b o i l i n g point). The fractions obtained were spread over the 5 bulbs to give better separation. 19. g ^ c t r f i c a t i o n ^ ^ ^ a l January 12 - January 15. 'Characteristics of; Charges ••(a) 1330 c.c. of Sastraan Kodak decalin (unwashed) as used i n R e c t i f i c a t i o n ITo„ l(a) plus bulbs 2, 3 and . 4 of Rect Bulb 1 i f i cation Bn lb P No,. 4. Boil i n g Point of Fraction (°C) Volume of Fraction (c.c.) :Time for Fraction v;.:'.:.." : 'thrs;.") Rate of Fractionation (c,c'./hr.) Index of Refraction ApproximatguCompo s i t i on {%~ trans) 59.8-62.0 325 18.5 17.6; 1.46898, >100 KA. JL V (Zj 62.0- 62.4 180 10,0 ""18.0 1.46968 ' 100 -DUJ.D o . -62.4-61.6 361 19.0 19.0 1.46968 100 Bulb 4 61.6Y61.5 380 27,0 14.1 .1.46987 99.5 Bulb 5 • ' J ...... j- The high quality of fractions 2 and 3 as ir idicated "oy r index measurements suggested the p o s s i b i l i t y of further p u r i f i c a t i o n by r e c r y s t a l l i z a t i o n . This was attempted, but i t was found that a constant freezing point could not be obtained, A th i r d r e c t i f i c a t i o n was therefore necessary, 20. R e c t i f i c a t i o n No. 3 (a) January 26 - - J anua r y 28, 1938. C h a r a c t e r i s t i c s of Charge:. (a) 820 c . c , c o m p r i s i n g b u l b s 2,3 and 4 of •-'. R e c t i f i c a t i o n No . 2 ( a ) . B o i l i n g Po in t'Of F r a c t i o n (°C) Volume of F r a c t i o n ( c . c . ) Time f o r F r a c t i o n ( h r s . ) Rate of F r a c t i o n a t i o n ( c . c . / h r . ) . Index of R e f r a c t i o n Approx imate Compos i t i o n {% t r a n s ) B u l b 1 Bu l b 2 Bu l b 3 Bu l b 4 Bu l b 5 6 5 . 8 - 6 6 , 9 6 6 . 9 - 6 7 , 3 6 7 . 3 - 6 9 . 2 69 . 2 - 69 , 3 6 9 . 3 - 6 8 , 1 76 252 167 238 76 4 .5 14 .0 9 . 0 13 .0 6.0 . 17 .0 : 18 .0 1 8 . 5 / ' 18 ,3 1 2 , 6 " 1.46908 1,46953 1.46958 1.46953 1.45953 >100 100 100 100 100 The above r e p r e s e n t s our f i n a l r e c t i f i c a t i o n . The p r e s su r e was m a i n t a i n e d h i g h e r than p r e v i o u s l y , b e i n g kept a t about 18 rams. Bu l b s 2 , 3 , 4 and 5 were now combined t o g e t h e r and s ub j e c t e d to the c r y s t a l l i z a t i o n t r e a tmen t . I t was found t h a t about e i g h t c r y s t a l l i z a t i o n s were r e q u i r e d i n o rde r to o b t a i n the cons tan t f r e e z i n g p o i n t , and t h a t the v o l u m e t r i c y i e l d of the pure i somer was 165 c . c . E v i d e n t l y , t he e f f e c t o f the h i g h e r p r e s s u r e was a b e n e f i c i a l f a c t o r i n the remova l of the c o n f l i c t i n g i m p u r i t i e s . F o r t r a n s d e c a l i n , our f i n a l r e s u l t i s : F . P. = - 3 1 , 4 9 ± .2 °C. and 1 ^ 0 1.46953 R. D. Wa lke r and ¥ , E . Seyer gave: F . P. = - 3 1 . 2 9 — . 2 °C. and N? = 1.46968 -•I 21. PART -II The JDe t e rm i na t i o n o f _^hy_sJjoaIjConstants | o f C i s and Trans D e c a l i n S e c t i o n 1— V a r i a t i o n w i t h Temperature of D e n s i t y The method employed f o r t h i s purpose was an a p p l i c a t i o n of A r ch imedes ' P r i n c i p l e ( see accompany ing d i a g r am) . The f o rmu lae employed may he d e r i v e d as f o l l o w s : . L e t : T t r u e mass o f plummet i n vacuum Wa i r a mass o f plummet i n d ry a i r ) mass o f plummet i n pure wa te r ) Wwa m W l i s mass o f plummet i n d e c a l i n P a i r s d e n s i t y of d ry a i r Pwa s d e n s i t y of pure wa te r P l i = d e n s i t y of d e c a l i n V B volume of plummet at t ° C . Assume a n e g l i b l e buoyant e f f e c t o f l i q u i d s on immersed p o r t i o n of w i r e . . T - Wa i r « V P a i r and T - Wwa . V Pwa . . V E Wair. - Wwa Pwa - Pair To obtain P l i we again use this formula, substituting Pair by P l i . ". P l i - Pwa 4 - Wwa ~ Wli V The standard value of t employed i n my determinations was 2 0 . 0 0 ° C . and the values of WwagQ and ^wago w e r e used as equation constants. Hence: P l i * 4 a p o + W w a 2 0 ~ ^ l i t ° .0 •wa20 YV APPARATUS FOR DETERMINATION OF  DENSITY, SURFACE TENSION & VISCOSITY  OF ISOMERS OF DFCAI IN OVERHEAD PLATFORM - LEADS TO THERMOSTATIC CONTROL"" SLASS CONTAINER , LASS-ED, AMD EXTERNALLY LINED WITH HEATING COIL WIRE HEATER FOR CLOSE TEMPERATURE CONTROL SURFACE TENSION APPARATUS SENSITIVE LIQUID TUBE FOR AUTOMATIC THERMOSTAT iinufiiiiH'l ii.iiiiiiiiiiiiiiiiuii.iiuu milium BATH LI&UID (OIL, WATER OR ALCOHOL) 22. Having got V 2 Q from air-water measurements, Vt° could be calculated from - . y t ° = V 2 Q -4- ( V 2 0 ) ( t - 2 0 . 00) (.000038) where ,000038 = coe f f i c i e n t of cubical expansion of ) quartz glass plummet j from *- ^ 4 2 0 _ s I n t e r n a t i o n a l i ^waon s .99823 • ^ a i r o n * ,00120 l n ... , „ , 2 0 ) C r i t i c a l Tables ( a ) ^l£iali2£s_an_d Calculations for Cis Decalin Mass of suspension (constant) - o1219 gr. Mass of suspension 4 - plummet i n pure water at 20.00°C. = 22,6381 gr. .*. Mass of plummet i n pure water at 20,00°C. = 22.5162 gr. Mass of plummet i n dry a i r at 20.00°C.. - 31.0059 gr. .°. Volume of plummet at 20.00°C. (from formula) = 8.5150 c.c. 23. Temperature Mass o f su spens i o (T°C . ) 4 Plummet ( g r ) - 4 0 , 0 0 - 3 0 . 0 0 - 2 0 . 0 0 - 1 0 . 0 0 0.00 10 ,00 20.00 30 .00 40 .00 50 .00 60 ,00 70 ,00 80 .00 90 .00 100.00 110.00 120,00 130,00 140 ,00 150.00 160,00 170.00 180,00 23.1751 23.2402 23.3068 23,3715 23,4366 23,5020 23.5665 23.6311 23,6955 23,7599 23,8243 23.8873 23.9527 24.0169 24.0804 24.1460 24.2101 24.2773 24.3467 24.4154 24.4857 24,5551 Mass of plummet (g r ) 23,0532 23.1183 23.1849 23.2496 23,3147 23,3801 23.4446 23.5092 23.5736 23.6380 23.7024 23.7654 23.8308 23.8950 23,9585 24,0241 24.0882 24.1554 24.2248 . 24.2935 24,3638 24.4332 Volume of plummet (Vt c . c 8 .4988 8.5020 8,5053 8.5085 8.5117 8.5150 8.5182 8.5215 8.5247 8.5279. 8 ,5312 8.5344 8.5376 8.5409 8.5441 8.5473 8,5506 8.5538 8.5570 8.5603 8.5635 8.5668 D e n s i t y ( D p . of d e c a l i n ,9350 .9274 .9196 .9120 .9044 .8967 .8892 ,8817 ,8742 .8667 « 3 5 0 2 ,8519 .8442 .8368 .8294 ,8218 .8144 ,8066 .7986 .7906 .7825 .7745 24. (°) QbserTations and Calculations for Trans Decali Temperature :-v, t i ° C ) . 5 Mass of susTJensioi -4- Plummet \gv) i Mass of plummet (gr Volume of ) plummet (Vt c.c.' Density of decalin j --.-40. GO , v-.3Q.-dO.' ' ' 23.4114 23,2895 8,4988 .9072 23.4757 23.3538 8.5020. .8997.. . , - 1 0 . 00 23.5396 23.4177 8.5053 .8922 0.00 ' 23.6027 23.4808 8.5085 .3849. 10.00 23.6658 23.5439 8.5117 .8775 20.00 23.7296 23.6077 .8.5150 .8700 /; ; 30.00 : 23.7927 23.6703 8.5182 .8627 ,.40.00- 23.8559 23,7340 8.5215 - .8553 50.00 23.9190 23.7971 8.5247 ,8480. 60.00 23.9831 23.8612 3.5279 .3405 70.00 v 24.0472 23.9253 8.5312 .8331 [ 80.00 24.1120 23.9901 8.5344 , .8255 ;  90.00 24.1781 24,0562 3.5376 .8178 :! • V J 100.00 24.2424 24,1205 8.5409 .8104 !| 110.00 24.3106 .,' 24.1887 8.5441 ..8025 1 120.00 24,3736 24.2517 .8.5473 .7952 1 130.00 24.4390 24.3171 8.5506 ,. • .7876 t 140,00 . . '.' 24.5063 24.3844 8.5538 . .7798 150.00 24.5764 -.. 24.4545 8.5570 .7717 . i 160.00 .24.6448. 24.5229 8.5603 .7638 170.00 -./' 24.7164 .24.5945 8.5635. .7555 180.00 ; r ; 24.7865 24.6546 8.56-68 .7474 ; Eo r v i s c o s i t y measurements, an Os twa ld v i s c ome t e r was employed, ' T h i s was s u i t a b l y suspended, a l ong w i t h the s u r f a c e • t e n s i o n and d e n s i t y - m e a s u r i n g appa r a t u s , i n a c on s t an t - t empe r a t u r e b a t h , t h e r m o s t a t i c a l l y c o n t r o l l e d . ( see accompanying d i ag r am) . The ma thema t i c a l r e l a t i o n employed was the w e l l known equa t i on , f o r r e l a t i v e v i s c o s i t i e s i . e . U]_ . d-^ t-j U 2 d 2 t 2 i n w h i c h , f o r two l i q u i d s 1 and 2, " U " , " d " and " t " a r e r e s p e c t i v e l y abso l u t e , v i s c o s i t y , d e n s i t y and t ime to f l o w th rough the c a p i l l a r y employed. Hence, by knowing the v a l u e s o f " U " and M d " a t some s t a t e d t empe ra tu re f o r a p a r t i c u l a r l i q u i d , one may measure " t " a t t h a t t empe ra t u r e , and t h en , u s i n g these v a l u e s , o b t a i n a cons t an t i n the above e q u a t i o n . Th i s c on s t an t w i l l be s a t i s f a c t o r y f o r • o t h e r t empe r a t u r e s , however , o n l y when we assume the absence of - = changes i n the d imens ions of the c a p i l l a r y . The s t a n d a r d i z i n g l i q u i d used i n my expe r imen t s was pure benzene , and the s t a n d a r d i z i n g t empera tu re was 20°C. (a ) O b s e r v a t i o n s and C a l c u l a t i o n s f o r C i s D e c a l i n D e n s i t y of benzene a t 20°C = .8787 g r / c . c . ) f rom . )- I n t e r n a t i o n a l A b s o l u t e v i s c o s i t y of benzene a t 20°C <= .00649 , ) C r i t i c a l Tab l e s Observed t ime f o r benzene to run down c a p i l l a r y = 78 .3 s e c . V . Cons tan t < = « 0 0 6 4 9 - .00009433 d 2 t 2 ( 7 8 . 3 ) ( . 8 7 8 7 ) . * . Work ing E q u a t i o n i s : U s ( t ) ( d ) ( . 0 0 0 0 9 4 3 3 ) 26 Temperature (T°C) Time to f l o w th rough c a p i l l a r y ( t s e c . ) - 4 0 . 0 0 - 3 0 . 0 0 - 2 0 . 00 - 1 0 , 0 0 :• . 0 ,00 10 .00 20,00 30 .00 .40.00 V; 50 ,00 60 .00 ?oeoo;- 80 ,00 - 90 ,00 100,00 110,00 ' 120 ,00 130,00 140.00 150,00 160.00 170.00 180,00 .9350 .9274 .9196 .9120 . 9044 .8967 .8892 .8817 .8742 .8667 ,8592 ,8519 ,8442 .8368 ,8294 .8218 .8144 .8066 .7986 .7906 .7825 .7745 1730.0 1240,0 851 „0 636 . 0 489.5 392,8 319.4 266.0 224.5 192 ,2 167,5 149.5 132.5 117.4 105,6 95.7 87 .8 80 .4 74 .5 69 .0 64 .5 60 .2 A b s o l u t e v i s c o s i t y of d e c a l i n (D!) .15259 ,10848 .07382 .05472 ,04176 .03323 .02679 .02212 ,01851 ,01571 .01358 .01201 .01055 ,00927 .00826 ,00742 .00674 .00612 .00561 .00515 ! .00476 .00440 27, ( t ) g ^ T - I ^ ^ f o r Trans w u r , |Temperature (T°C) -=40.00 - 3 0 , 0 0 - 2 0 , 0 0 - 1 0 , 0 0 0.00 10 ,00 20.00 30.00" 4 0 e 00 50 ,00 60,00 70 ,00 80 ,00 90 ,00 100.00 110.00 120,00 130 c 00 140.00 150.00 160.00 170,00 180,00 D e n s i t y (4) .9072 .8997 .8922 .8849 ,8775 ,8700 ,3627 ,8553 ,8480 ,8405 ,8331 .8255 ,8178 ,8104 .8025 .7952 .7876 .7798 .7717 ,7638 ,7555 .7474 Time to f l o w th rough Ah s o l u t e v i s c o s i t y of" c a p i l l a r y ( t s e c . ) d e c a l i n (u|) 853,0 629,8 484,9 383.5 310,6 •258.3 219.4 187,0 161.3 141 .1 125.5 112.6 102 .0 92 .5 84 .2 77 .0 72 ,1 66.6 . 63 .0 58.6 54.. 5 51 .2 .07300 .05345 ,04081 .03201 .02571 .02120 ,01785 ,01509 ,01290 ,01119 ,00986 ,00877 . 00787 .00707 .00637 ,00578 ,00536 .00490 • .00459 .00422 .00388 .00361 28 Section 111--variation with Temperature of Surface Tension. Determinations of surface tension were carried out employing the method of Richards, Speyers and Carver 1 (see accompanying diagram). -Their equation i s of the form whe're Y surface tension d •» density of l i q u i d used K t constant H •& difference In levels in the two tubes, corrected for the meniscuses. The value of H i s given by the equation ; H s ( h x -• h 2) - V ( r l " r2) - 3 where h^ and hg a observed heights of c a p i l l a r y in the two tubes above plane surface, r^ and r 2 - r a d i i of the two tubes. Since the l a s t term i s neglible in this work, the equation becomes H' s (h-L - h 2) - ( r2 " r l ) 3 : ;• \ The constants K, r 1 and r g for the apparatus used in my measure- 2 ments were determined by R. Bennett by calibration with pure , benzene.• Their values ares i K = 23.63 dynes, cms./gr. (corrected for meniscuses) • r-^  r .033 cms. r 2 - ,121 cms. ' 1. Richards, Speyers and Carver; J. Am. Chem. Soc., 46, 1196 (1924) 2. Bennett, R., B. A. Sc., Thesis (1935). . 29, (a) O b s e r v a t i o n s and Calculations f n r p.i«, Decalin Temperature :: v(T°C) - Difference i n levels , (jti^ - .tig cms. \ Corrected Difference i n levels (H cms.) i Density (4) Surface Tension • of Decalin (0^ dynes/cm)r : ; -40.00 ; -30.00 1.750 1.7 21 ,9350 38.02 ; / -=20. 00 1,710 1.681 ,9274 . 36.83/ / / -10.,00; 1.670 i;64i .9196 35.65 ' • • j ;?v.;^.a.ob- 1,630 1.601 ,9120 34.50 I 10.00 1.590 ' 1.-561 .9044 : 33,36 ' j 20.00 1.548 . • 1.519 " .8967; 32.18 • ' . j V; 30.00 1.505 1.476 • . 4 •. .8892 31.01 ' j ;>:;:\4o,.oo . 1.460 1 © 431 ,8817 29.81 • ' | 50.00 l Q 4 l 5 1.386 .8742 28.63 60, 00 ~ 1,380 1 © 3 5 X .8667 27.67 ; 1/7/0.00 1,350 1«3 2IL ,8592 26.82 ; >80.Q0 , 1,315 1.286 .8519 25.88 . || 90,00 1.280 1.251 .8442 24.95 ;| ; >;ioo-.oo : 1.245 1.216 .8368 24.04 r i i o .oo 1.210 1.181 '/ .8294 23.14 /jt2Q,.0O 1.175 1.146 : .8218 22e 25 rt •130.00 - 1.140 IL * *L JL 1 .8144 21.38 : 140.00 "1.108 1.079 .8066 20.56 ' 150.00 1.07 6 1,047 .7986 19.76 , 160. :qo^ 1.040 1.011 .7906 18.89 . : 170.00 1.005 •'• .976 .7825 18.04 >:i8o:.oo _ .968 - .939 .7745 17.18 |'j •  ; 1 W - P f t s e r v a t l o n a ^ ^ f o r T r a r m Temperature (T ° C ) 2 Difference i n levels (hj - hg cms. Corrected Differenc in levels (H cms. ) e Densit] 7 Surface Tension - of Decalin Qt dynes/cm) -40.00 V -30.00, 1.675 1,646 .9072 '35,29 20,00; 1,635' 1.606 .8997 34.14 ,-io,ob 1.592 1.563 ,8922 3 2 e 9 5 p'- 0.00 19 5 5 5 1.526 .8849 31.91 ' 10,00 : : 1.518 1.439 .8775 30.87 .'' 20.00 1.483 1.454 •' . .87 00 29.89 "I: 30.00 ' 1.445 1.416 ..8627 28,87 4O.O0 " 1.405 1.376- , .8553 27,81 50.00 ' 1.365 1.336 ,8480 26.77 ] 60.00 1.329 1.300 \ .8405 25.82 . •70,00 1.290 1.261 . 8331 24.82. 80,0,0 :- ' 1.257 1.228 .8255 23.95 9 0 . 0 0 c 1.220 1.191 .8178 23.02 :;10/0^00 •.; : 1.179 1,150 .8104 22,02 : 110.00 1.139 1.110 .8025 21.05 1-20.00 " . 1.105 1.076 .7952 20.22 130.00 1.071 1.042 .7876 19.39 T40.00 1.041 1.012 .7798 18.65 150.00 .1.008 ,979 .7717'. : 17.85 160.00; .970 .941 ,7638' 16.98 170.00 .i .935 .906 ,7555 16.17 180,00 .903 .874 .7474 15,44 31 PART III The Mathematical Treatment of the ^ P T - S ^ + S I Results The following work represents an extensive study of the results obtained for the three physical properties of c i s and trans decalin, Por the most part i t involves the application of well-known formulae, the main object being to secure values for various theoretical quantities and constants, and to note 1 the effect of temperature on these values. By this means, several conclusions are drawn regarding transitions in the structure of • • decalin. Also, in this work, values for such quantities as latent heats of vaporization and fusion, c r i t i c a l temperature, etc. were calculated, the object being to have these calculated quantities as guides i n further research to be done on the decalin. 1, A Study of the Plotted Results for the Physical Properties of Cis Decalin. The accompanying graph shows the effect of temperature on the physical properties of c i s decalin. Close examination of ' these curves shows that each i s marked by characteristic breaks', indicating possible transitions. It w i l l be noticed that the curve for surface tension i s linear but shows a break at 50° - 60°- and another at 120° - 130° C.; the curve for logarithm of v i s c o s i t y i s linear but shows four breaks at approximate-temperatures of -5° - 0° C.j 35° - 40° C.| 60°- 70° C ; 120° - 130° C. After the cooling down to -30° C., the physical properties were remeasured at 20° C. Since no changes were observed the following conclusions may be drawn: I E o cn CD o «*3 += 00 <U u a glco . o CO IT «7 <D E -I. 4 - 4 — • o o 0> T f ! I co CO U0I9U9J^ SDDjJflg f I § i K|I90D9I^ JO LULJ|UD6O-|' I 3 I 3 2 (!) i f a tran s i t i o n from one form to another does take place on lowering the temperature, then the f orm 'produced must "be very unstable at 20° C. (2) i f a transition to a form stable at 20° C does occur on lowering the temperature, then the tran s i t i o n must be a time • reaction, requiring a much longer time than was used i n these experiments. Similarly, after the heating to 180° C., the physical ' _ . • .. . . . . . . .... .. j properties were remeasured at 20° C. Considerable changes were [ discovered, as the following record shows s ii (1) in surface tension apparatus, H had increased to 1.551 cms.,' corresponding to XgQ = 32.92. This i s an increase of 2.30% over jf the true value $20 " 32.18 for c i s decalin. • i!j f2) in density apparatus, the mass of suspension -\- plummet \;j had decreased to 23.4902 gr., corresponding to s ,8982. This 'p i s an increase of ,17% over the true value IK = .8967 for 4| c i s decalin. . 2 (3) i n v i s c o s i t y apparatus, the time had increased to. 403.5 see.,:! corresponding to 1J s .03419. This i s an increase of 2,89% over || ' If HI; the true value U20 ~ .03323'for cis decalin. (| This evidence, then, along with that obtained from the graph, i s ''j su f f i c i e n t to show that changes occur on heating, and that these | changes are accompanied, by a certain amount of i r r e v e r s i b i l i t y . ;| To investigate further the effect of heat, fresh samples of :;| pure c i s decalin were employed and treated by the following scheme; !l 1. Apparatus heated to 70°G. _ Readings checked with previous readings at this temperature.> Apparatus cooled to 20°G, Readings checked with previous » , readings at this temperature'. - 2. Apparatus heated to 100°C. Readings checked with previous readings at this temperature. Apparatus cooled to 20° C. Readings checked with previous readings at this temperature,. | 3. Apparatus heated to 120°C. Readings checked with previous ; readings at this temperature.. •• <•. f Apparatus cooled to 70° C. Readings "for density'and viscosity;) checked with previous' readings I; hut i n surface tension apparatus • H had increased to 1,326 cms-, jj 4. Apparatus heated to 130°C, Readings checked with previous | readings at this temperature, - • |: ' ' . . . . . . . . . . ||! Apparatus cooled to 70° C. Readings for density and viscosity!; checked with previous readings f hut in surface tension apparatus '- H had increased to 1,336 cms. 5. Apparatus heated to 140°G. Readings checked with previous readings at this temperature. Apparatus heated to 160°C. Readings checked with previous readings at this temperature. . <- Apparatus cooled to 70° C. Readings for density and v i s c o s i t y checked with previous readings hut i n surface tension"apparatus H remained at 1,536. cms. Apparatus cooled to 20° C. Readings for density and vi s c o s i t y checked"wlth"previous :'readings btit in" surface" tension apparatus I-I had changed to 1.534 cms. With respect to the above results, i t w i l l be noted that no changes in surface tension (which appears to be more sensitive than either density or viscosity) were observed u n t i l after the decalin - had been subjected to 120° C. Now the graph indicates that a radic a l 34. change occurs i n the region 50° - 60° C. Since no changes were observed on cooling to 20° C. even after the heating to 100° C , we are thus led to the conclusion that whatever happens around 50° - 60° .0. i s reversible. The ease of r e v e r s i b i l i t y i s apparently great, as the cooling was accomplished quickly. The p o s s i b i l i t y that the abrupt change at 50° - 60° C. may have been due to some change i n the apparatus, may be discredited, as a l l readings made in the heating to 70°, 100°, 120°, 130°, 140°and 160° i n the above check test (using fresh decalin) duplicated the previous readings. The heat treatment at 120° and 130° produced a change i n the- surface tension at 70°C. and 20°C., no further change being effected by higher heating. This apparently indicates t r a n s i t i o n i n the - region 120° - 130° C. Since the readings at 120°, 130° and higher temperatures checked with previous readings, and since the time of heating was f a i r l y short, i t may be concluded that the forward action of this t r a n s i t i o n i s rapid. The backward action, as the cooling shows, i s incomplete, for at 20° C. H now possessed the value of 1,534 cms which corresponds to K » 32.50, or an increase of .99% over the true value for c i s decalin. The increase at 20°C. i n the previous readings was, as stated, 2.30%. However, since the check test was done in much shorter time than were the previous observations, i t would appear that the longer the heat treatment, the greater i s the tendency to produce i r r e v e r s i b i l i t y . II. A Study of the Plotted Results for the Physical Properties of Trans Decalin., The accompanying graph shows the effect of temperature on the physical properties of trans decalin. As In the case of the cis form, examination of the curves reveals characteristic breaks, again . « 3 =^ 3 CO C D o o a CO a o Q CO j-. C_3 ^7 S ¥UdQ "I- I a sa. s I I indicating possible transitions. I t w i l l be noticed that the curve for surface tension i s linear but shows breaks at -10° - 0-° C. , 50° - 60° C.s and 120° - 130° C.; the curve for density i s linear . but f a l l s "off rapidly beyond 80° C. ; the curve for logarithm of • • ^ '. v i s c o s i t y i s linear but shows four breaks at approximate temperatures of -10° to -15° C . | 10° - 20° C f 60° - 70° G. ; 120° - 130° C. . ¥o change was observed i n the physical properties of trans o o decalin at 20 C. after the cooling down to -30 C. Hence, regarding the cooling treatment, the same conclusions may be drawn for trans as for c i s , Following the heat treatment to 180° C., the physical properties were again measured at 20° C, However, unlike the case for cis decalin no changes were observed for trans, This would then point to .the fact that any transitions in structure produced by heating trans decalin ( the graph's show that such transitions must occur) are t o t a l l y unstable at lower temperatures? that i s , the reactions are reversible. As a b r i e f summary we may now say that: (1) between -10° and 0°G,, a completely reversible reaction occurs for, both isomers. (2) between 50° and 60°C., a completely reversible reaction occurs for both isomers, (3) between'120° and 130°C., a reaction occurs, completely reversible for trans, but not so for c i s . IIL The Variation with Temperature of Density. The effect of temperature on the linear characteristics of the 4 o D v.s. t relationship has been previously mentioned. For •' 36 c i s d e c a l i n , the l i n e a r s e c t i o n . r a n g e s f r om -30°C.. t o 130°C. and i s g i v en f a i r l y w e l l by = .9120 - .000752 t D e v i a t i o n s from, t h i s equa t i on do no t exceed, . 02% . "... * * "For .trans d e c a l i n , the l i n e a r , r e l a t i o n s h i p ranges f r o m - 3 0 ° C . to 80°0 and i s w e l l r e p r e s e n t e d hy K t s .8849 - .000742 t 1 ' • • D e v i a t i o n s f r om t h i s equa t i on do not exceed .01%. The i n c l u s i o n c square terms i n an a t tempt to extend these equa t i ons over the whole t empera tu re range s t u d i e d , was found to he u n s a t i s f a c t o r y . As a means o f g e t t i n g approx imate v a l u e s f o r t he c r i t i c a l d e n s i t i e of the two i s ome r s , the l aw of C a i l l e t e t and Ma t h i a s was i n v e s t i g a t e d . The accompany ing t a b l e and graphs i l l u s t r a t e the manner of p r o cedu r e . V a l u e s o f " d " ( s a t u r a t e d vapor d e n s i t y ) were c a l c u l a t e d from., the; i d e a l gas law,, u s i n g vapor p r e s s u r e s p r e v i o u s l y determined- by- Nemetz and- . Henniker-*-. On p l o t t i n g average d e n s i t y a g a i n s t t empe ra tu re , t h e - u s u a l s t r a i gh t - " l i n e s were o b t a i n e d . F o r c i s , the l i n e i s w e l l g i v en by _±_ _-___L_ = .4560 - .000376. t D e v i a t i o n s from, t h i s equa t i on do not exceed ,02% and f o r t r a n s by — £ - = .4424 - .000368 t . . . 2 .. .. D e v i a t i o n s f r om t h i s e qua t i o n do no t exceed .01% ,. ... From the work on s u r f a c e t e n s i o n ( see page 39) we may take the c r i t i c a t empera tu res o f c i s and t r a n s as 428°C, and 410°C. r e s p e c t i v e l y . ; On - , s u b s t i t u t i n g i n t he above equa t i on s ( o r e x t r a p o l a t i n g ) , we thus o b t a i n a c r i t i c a l d e n s i t y o f ,2950 f o r c i s and .2915 f o r t r a n s . S i n c e . t h e da t a show the l i n e f o r t r a n s to f a l l o f f g r a d u a l l y a t the h i g h e r t empe ra t u r e s , i t i s p r obab l e t h a t the c r i t i c a l d e n s i t y o f t r an s i s l owe r than , 2915 , p o s s i b l y around .2880 . 1. Eemetz , H. and Henn i k e r , C . , M.A. S c . and B .A . S c . r e s p e c t i v e l y The s i s ( 1938 ) . for c i s Temperature ( eC) - 5 0 - 2 0 - 1 0 0 1 0 20 3 0 4 0 5 0 60 70 8 0 9 0 1 0 0 1 1 0 1 2 0 1 3 0 140 150 1 6 0 170 180 D; . 9 3 5 0 . 9 2 7 4 . 9 1 9 6 . 9 1 2 0 . 9 0 4 4 . 8 9 6 7 . 8 8 9 2 ; 8 8 1 7 . 8 7 4 2 . 8 6 6 7 , 8 5 9 2 . 8 5 1 9 . 8 4 4 2 . 8 3 6 8 . 8 2 9 4 . 8 2 1 8 . 8 1 4 4 . 8 0 6 6 . 7 9 8 6 . 7 9 0 6 . 7 8 2 5 . 7 7 4 5 D : 4 d t o . 0 0 0 0 0 . 0 0 0 1 . 0 0 0 1 . 0 0 0 1 . 0 0 0 1 . 0 0 0 1 . 0 0 0 2 . 0 0 0 3 . 0 0 0 3 . 0 0 0 5 . 0 0 0 7 . 0 0 0 8 . 0 0 1 1 . 0 0 1 4 . 0 0 1 8 . 0 0 2 2 . 0028 . 4 6 7 5 . 4 6 3 7 . 4 5 9 8 . 4 5 6 0 . 4 5 2 2 . 4 4 8 3 . 4 4 4 6 . 4 4 0 9 .4371 . 4 3 3 4 . 4 2 9 6 . 4 2 6 0 . 4 2 2 2 . 4 1 8 5 . 4 1 4 9 . 4 1 1 2 . 4 0 7 6 . 4 0 3 8 . 4 0 0 0 . 3 9 6 2 . 3 9 2 3 . 3 8 8 6 for trans 74~ . 9 0 7 2 . 8 9 9 7 . 8 9 2 2 . 8 8 4 9 . 8 7 7 5 . 8 7 0 0 . 8 6 2 7 . 8 5 5 3 . 8 4 8 0 . 8 4 0 5 . 8 3 3 1 . 8 2 5 5 , 8 1 7 8 . 8 1 0 4 . 8 0 2 5 . 7 9 5 2 . 7 8 7 6 . 7 7 9 8 . 7 7 1 7 . 7 6 3 8 . 7 5 5 5 . 7 4 7 4 0 0 0 0 0 0 , 0 0 0 1 . 0 0 0 1 . 0 0 0 1 . 0003 . 0 0 0 4 . 0 0 0 6 . 0 0 0 8 . 0 0 0 9 . 0 0 1 1 . 0 0 1 2 . 0 0 1 6 . 0018 . 0 0 2 2 . 0 0 2 6 . 0 0 2 9 . 0 0 3 5 2 Z£- t t . 4 5 3 6 . 4 4 9 3 .4461 . . 4 4 2 4 . 4 3 8 7 . 4 3 5 0 . 4 3 1 4 . 4 2 7 7 , 4 2 4 0 . 4 2 0 4 . 4 1 6 7 . 4 1 3 0 . 4 0 9 3 . 4 0 5 6 . 4 0 1 8 . 3 9 8 2 . 3 9 4 6 . 3 9 0 8 , 3 8 6 9 . 3 8 3 2 . 3 7 9 2 . 3 7 5 4 .38. As a means o f g e t t i n g app rox ima te v a l u e s f o r the c r i t i c a l p r e s s u r e s , we cannot use the i d e a l gas l aw due to the h i g h p r e s su re s \ i n v o l v e d , bu t we may make use of the equa t i on o f c o r r e s pond i ng s t a t e s ( ^ + p ) ( ^ • " 1 } * 8 0 P t _ » fa * < V t _ = dc and 8 - T t . Yc d t • T V - In t h i s e qua t i o n TT - P t _ , (J) - V t _ - dc P c Vc . t . T C . . • Emp loy i ng the v a l u e s o f dc = .2950 f o r c i s and dc - .2880 f o r t r a n s - p a r t i a l p r e s s u r e s a t 100°C. of P 1 0 Q = 5.821 cms. f o r c i s and. ^100 = 1 6 ' 0 4 1 cms. f o r t r a n s ; and c a l c u a l t i n g d 1 0 Q f rom the i d e a l gas law,, we f i n d t h a t Pc i s equa l to 4 6 . 1 and 45 . 0 atmospheres f o r c i s and t r a n s r e s p e c t i v e l y . I V . The V a r i a t i o n w i t h Temperature o f S u r f a c e T e n s i o n . ; As p r e v i o u s l y s t a t e d t he cu rves f o r s u r f a c e t e n s i o n a r e l i n e a r ' - b u t show c h a r a c t e r i s t i c b r e a k s . Eo r c i s d e c a l i n , the c o n d i t i o n s a re w e l l r e p r e s e n t e d b y : (a) = 3 4 . 5 0 - .1162 t wh i ch ho l d s f r om -30°C . to 50°C. (b) K.s 33 ,24 - ,0920 t wh i ch h o l d s from. 6O?Cy«$Q-%%.0°0.. ( c ) ft = 32 .24 - .0835 t wh i ch h o l d s f r om 130°0. to 130°C. «r:, D e v i a t i o n s i n e qua t i o n (a) do no t exceed .09% and i n equa t i on s (b) and ( c ) do not exceed .1%. Eo r t r a n s d e c a l i n , we have the f o l l o w i n g : (a ) -fl : 31 ,78 -• .1170 t wh i ch h o l d s f r om - 30 °C . to - 10°C . (b) # = 3 1 . 9 1 - .1020 t wh i ch ho l d s f rom 0°G. to 50°0 . ' (c) 31 .39 - .0930 t wh i c h h o l d s f rom 60°C. to 120°C. • ( d ) if • 30 .33 - .0835 t wh i ch h o l d s f r om 130°C. to 180°C. . . D e v i a t i o n s i n equa t i on s (a) and (b) do not exceed .09% and i n equa t i on s ( c ) and (d) do not exceed .4% and .1% r e s p e c t i v e l y . . As a means of g e t t i n g an approx imate v a l u e f o r the c r i t i c a l t empera tu re o f each of the two i s ome r s , the Ed t vos equa t i on was 3 9« employed? t h i s b e i n g g i v e n by j f(Mvf s k ( t c — t - 6 ) . ' S i n c e t h i s e q u a t i o n c o n t a i n s two unknowns, k and t c , i t was n e c e s s a r y to use p a i r s of temperatures t o e f f e c t a s o l u t i o n . The r e l a t i o n h o l d s s t r i c t l y f o r the h i g h e r temperatures but i n or d e r to show what happens a t lower temperatures, the accompanying t a b l e shows c a l c u a l t i o n s c o v e r i n g the whole temperature range. The f o l l o w i n g i s a b r i e f summaryi 1. f o r c i s d e c a l i n (a) from -30°C. to 50°C., average k = 2.S3 and average t c a 353*3 G e (b) from 60°C. to 180°C., average k « 2.24 and average t c 428.6° C. (c ) assuming Guldberg-Guye law, Tc <= ~ Tb, to h o l d , and t a k i n g b o i l i n g p o i n t of c i s as 193°G., we get t c » | (273 4- 193) -273 ® 426°C. T h i s i s i n good agreement w i t h r e s u l t s g i v e n i n (b) 2, f o r t r a n s d e c a l i n 0 o (a) from -30 C. to 50 G., average k = 2.51 and average t c - 374.5° C. (b) from 60°C„ to 180°G., average k s 2.24 and average t c = 409.5° C. (c ) assuming Guldberg-Gnye law to h o l d and t a k i n g b o i l i n g p o i n t of t r a n s as 185°C; we get t c a | (273 f 185) - 273 s 414°G. ' > T h i s i s i n good agreement w i t h r e s u l t g i v e n i n ( b ) . The v a l u e , k = 2.24, f o r Eotvos c o n s t a n t , i s normal and the same 5 5 f o r b o t h c i s and t r a n s ; s i n c e i t i s not ab n o r m a l l y low, no a s s o c i a t i o n 4 0 , l e u l a t i o n s o f _ C r i t i c a l Temperature and E 5 t r o s flhn«t:»Ti+. - r ~_ ; . ' • :- • .•".trans • .•--•-•'•-—••> P a i r o f Temperatures (°c) 3 V a l u e of t 3 V a l u e o f i c V a l u e of t< (°C) : V a l u e o f k -•20, -30 356.4 2.79 343.1 2.74 - 1 0 , 0 . 363,0 2.74 376,4 2,50 -10> ; 20 363.1 2.74 383 .1 2.45 -10 , 30 358.6 2. 78 380.8 2 .47 -30 , 50 ..- 352.3 2.82 363.7 2.60 ' : o;5 20 359,3 2,77 383 .1 -2.45 • • " I 0, 30 355.1 2,81 380.8 .2,47 | 1 0 , 20 348 .6 2.87 396,4 / , 2.37 [ 20, 30 348.5 2.87 369.3 2.55 . ' j - 30, 40 340.1 2.95 ' 358.5 2.64 .;! .'• 40, 50 341.7 2.93 359.0 2.63 50, 60 410.8 . 2,56. 388,. 6 2.40 - 60, 80 ; 436.9 2.19 393.7 2.36 -. j ; ; 5-o, i oo 424,5 2,27 385.3 2.42 • ' j - 70,; 90 418.6. 2.31 403.7 2 9 29 I, ,70, 100 418.5 2,31 389.0 2.39 , | SO, 120 420.1 2,30 384.1 II. 2.44 . •. 1 ; n o , i2o 429.0 2.24 411,7 2.20 110, 130 425.8 2.26 413.8 .2.19 90, 140 4 28.4 2 » 25 401.1 2 . 3 i ... ;i . l50»;;no v 449,0 2.09 449 .0 1.94 . ' '• '•'1 ISO,-. 150 120, 170 ;130, 160 130, 180 60, ISO 150, 160 160, 170 441.7 433.7 440,4 432,3 428.9 422.4 426.0 2 © X 5 '. 2.20 2.15 2 ft 2 J. 2.24 2,30 2.27 428.7 415.4 •418.1 420,7 405.8 393,3 414 .1 2,08 2,17 . j ! 2 .15' . '| 2 91 3 [ 2.28 2.39 2 ft 2. Q occurs at the higher temperatures. "With the purpose of obtaining further confirmation of the . above results for c r i t i c a l temperature, Ferguson's equation 1 was next investigated. This i s of the form • I t - U i - » » ) " where "a" and "n» are constants. On d i f f e r e n t i a t i n g , we'obtain the straight l i n e equation y ( dt ) t 1__ hK c\Vt' c n ""an .We would thus expect that at the c r i t i c a l temperature, where Y t 1 i /) + a 0, — - —- ? 0, from which tc = - . a The accompanying table gives the necessary calculations and the graphs show the result of plotting X. ( ) v.s. t. Since the graphs are by no means regular, no attempt was made, to determine tc from any one portion of them. However, i t w i l l be noted that the plot for cis i s approximately li n e a r i n three sections, and the breaks occur i n the previously mentioned ranges of -10° - 0°C., 50° - 60°C., and 120° - 13Q°C. The plot for trans appears a l i t t l e more complex. The characteristic changes at -10° - 0°C., 50° - 60°C, o o and 120 - 130 G. are quite evident, but i n addition there are breaks at 80°C and 100°C. V. Determination of Parachors. " Calculations of parachors were carried out employing Sugden's 2 equation P •_ M Y .25 D t - a t 1. "Surface Tension and Surface Energy" by R. S. Willows & E. Hatschek ' 2. Sucden T ( 3 R D E D « ) 4 3 - 4 4 . g d C n ' J- c^era. Soc., 125, 1177 (.1924). Temperature Range { t » 20°C Da t a and C a l c u l a t i o n s I n v o l v e d c i s t"1 "~ - 3 0 to - 10 - 2 0 t o 0 - 10 to 4 1 0 • 0 to 20 10 t o 30 20 to 2 40 30 t o 50 40 to 60 50 to 70 60 to 80 70 to 90 80 to 100 90 to 110 100 to 120 110 to 130 120 to 140 130 to 150 140 to 160 150 to 170 160 t o 180 Mean (°C) - 2 0 - 1 0 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 A* in) t h i s Rang el 2.37 2.33 2.29 2.32 P 2.37 2.38 2.14 1.81 1.79 1,87 1.84 1.81 1.79 1.76 1.69 1.62 1.67 1.72 1.71 dt dT t. 8.44 8.58 8 ,73 8 .62 8 .50 8.44 8 .40 9.34 11 .05 11.18 10 .70 10 .88 11.05 11 . 18 11 . 35 11.83 12 11.98 11 .62 11 .70 mean t . i n P l o t t i n g F e r g u s o n ' s E q u a t i o n . t r a n s ' - 36 .83 35,65 34 .50 33.36 32.18 , 31 . 01 29.81 28,63 27.67 26 ,82 25.88 24.95 24.04 23.14 21.38 20.56 19.76 18.89 18,04 .311.0 306.0 301.5 287.5 273,5 262.0 250.5 267,5 30G.0 300 .0 277.0 271,5 265.5 258.5 253, o| 253.0 253.5, 236,5| 219.5 211. C A}f i n t h i s Range 2.34 2.23 , 2 . 0 8 2.02 2.00 2.08 2.10 1.99 1,95 1.87 1.80 1,93 1.97 1.80 1.66 1.57 1,54 1.67 1.68 I . 54 dt: mean t 8 .54 8.97 9.61 9,90 10.00 9 ,61 9.53 10.05 10.26 10 .70 11.10 10;. 37 10,15 11.10 12.05 12.74 13 . 00 11,95 11 ,90 13 .00 34.14 32.95 31 .91 30.87 29.89 28.87 27.81 26.77 25.82 24,82 23.95 23.02 22 .02 21,05 20.22 19,39 18.65 17.85 16.98 16.17 291.5 295.5 307 .0 3 05.5 298.9 278 .0 265. 0 269. 0 265.0 265.5 26.6.0 238.5 224,0- 234,00 243,5 247. 0 242.0 1 214.0 202.0 210.0 4 3 , The accompanying table gives the necessary data and calculations. The results show that we may take averages for each isomer over two separate temperature ranges, thus; 1. for cis decalin (a) from -30°C. to 30°C, P - 366.9 (b) from 40°C. to 150°C, P * 365.6 2. for trans decalin (a) from -30°C to 40°C S P - 371*1 (b) from 50°G to 150°C, P = 369.7 Parachor of Double 6-Membered Ring. Prom Sugden's work we have the following parachors: for carbon, P - 4.3; for hydrogen, P = 17.1; and for double bond P s 23.2. Knowing the formula of decalin to be C^O^IS and assuming the additive nature of the parachors, we obtain the following values for the parachor of the double 6-membered ring; 1. from cis decalin (a) from -30°C to 30°G, P = 11.1 (b) from 40°C to 150°C, P = 9.3 2. from trans decalin (a) from -30°C to 40°G, P = 15.3 (b) from 50°C to 150°C, P = 13.9 As a supplement to.this work, the parachor for this structure was worked out from data on naphthalene. Prom International C r i t i c a l . ' Tables we are given the values at 80.2°G. (melting point)s D 4 = .9779, = 32.26, and P = 7,5 mms „ The calculated parachor from this data is 312.1. On subtracting parachors due to carbon, hydrogen and 44. Data and C a l c u l a t i o n s o f Pa r a cho r s t empe ra tu r e (°C) -30,00' -20.00 -10.00 0 . 00 10.00 2 0 , 00 30.00 40,00 50,00 60.00 70,00 80.00 90.00 100.00 110.00 120.00 130.00 140.00 150.00 1.60.00 170.00 130.00 38,02 36.83 35.65 34,50 33.36 32.18 31.01 29.81 28,63 27.67 .26,82 25,88 24,95 24. 04 23,14 22.25 21,38 30.56 19.76 18.89 18.04 17.18 CIS .9350 :.9274 .9196 .9120 .9044 .8967 .8892 ,8817 .8742 .8667 .8592 ,8519 .8442 .8368 .8294 .8218 ,8144 .8066 ,7936 .7906 .7325 .7745 0 0 0 0 0 0 . 0 0 0 1 . 0 0 0 1 . 0 0 0 1 . 0 0 0 1 . 0001, Pa ra cho r .000 . 0003 .0003, .0005 . 0007 ,0008 . 0011 .0014 0018 00221 . 0023 366.9 366.9 367.1 367.1 367,1 366.9 366.6 . 366.1 365,. 6 365.6 365,9 365.8 365.8 365,7 365,5 365.4 365.1 365,2 365.3 365.1 364.9 364.4 35.29 34.14 32,95 31.91 30.87 29.89 28,87 27.81 26.77 25.32 24.82 23 a 95j 23,02 22.02 21.05 20.22 19.39 18.65 17,85 16.98 16.17 15.44 trans. .9072 0 Pa r a cho r .8997 ,8922 .8849 .8775 .8700 .3627 .8553 .8480 .8405 ,8331 .8255 ,8178 .8104 .8025 ,-7952 .7876 .7798 ,7717 .7638 .7555 ,7474 0 0 0 0 0 . 0 0 0 1 , 0 0 0 1 , 0 0 0 1 ., 0003 , 0004 .0006 .0008 .0009 .0011 ,0012 .0016 . 0018 . 0022 .0026 ,0029 .0035 371,1 371.1 371,0 371.0 371.1 371.3 371.2 •370;© 370.6 370.6 370.3 370,5 370.4 369.7 369.2 . 368.9 368,8 369,0 369.0 368.4 363.1 368.1 4 5 „ double bonds we obtain P = 11.3 for that of the double S-membered ring This agrees f a i r l y well with the parachor from c i s decalin from -30°C to 30°C., indicating a s i m i l a r i t y i n configuration. As stated, the value P = 23.2 for the double bond, i s used in the calculations. It may be mentioned, however, that since- a double bond possesses modified properties i n a 6-element ring to what i t possesses i n say ethylene, we may not be j u s t i f i e d i n assuming the parachor the same for both cases, Parachor of Single 6-Membered Ring. For t h i s , Sugden gives the value P = 6.1, Since this was, no doubt, obtained from data on benzene (unsaturated), i t was of interest to see i f the same result would be obtained from data : on Cyclohexane (saturated). Prom International C r i t i c a l Tables we are given the values at 20°C. : D 4 » ,7790, lf = 25.30, and, P = 76.9 rams. The calculated parachor from this data i s 242.2. On subtracting parachors due to carbon and hydrogen we obtain P • 8,2. for that of the single 6-element ring. This d i f f e r s considerably from Sugden1s value, and, as with the double ring, i s probably due to some effect of the double bonds. V I. The Total and Molecular Surface Energies. The accompanying table shows the calculations of t o t a l surface energy, where t o t a l surface energy = K + T ( — ) . The value of dt M ( r e a l l y -AL) was obtained by taking A t = 10°C and getting dt A t corresponding values of . The following i s a b r i e f summary of the results; 1, for cis decalin (a) from -30°C to 50°C, average £l » .117 and average t o t a l dt ' " - - - ~ - surface energy = 66.'44 ergs. 46. Data and. Calculati o Temperatur (°C) - 3 0 . 0 0 - 2 0 , 0 0 - 1 0 . 0 0 ' 0,00 10 .00 20.00 30 ,00 40 ,00 50.00 60 .00 70 .00 80 ,00 90 ,00 100,00 110.00 . 120.00 130,00 140,00 150.00 150.00 170,00 180.00 T t 38 .02 36.83 35 ,65 34 ,50 33.36 32.18 31 ,01 29 .81 23,63 27,67 26 .82 25,88 24,95 24.04 23,14 22,25 21,38 20,56 19.76 13,39 18,04 17.18 ^^JlotaJ^3Ji^ Surface Energies. cis j t r a n s A * 1.19 1.18 1,15 1.14 1,18 1.17 1.2Q 1.18 ,96 .85 .94 .93 ,91 .90 .89 .37 .82 .80 .87 .85 Total Molecular Surface Surface Energy Energy •_.Lergs ) . ( ergs ) 66 .45 1062.6 66.43 1034.9 66 .42 1007.4 980.3 65.44 66,47 66,46 66.46 ' 6 5 . 43 66 .42 56,97 . 57 ,00 56.94 56.89 56,86 56.34 56.83 56,84 56 .90 56.98 56,99 57 ,02 57 .04 953 .2 924.7 396 .2 865,4 836.8 813.4 793 .0 769,6 746,4 723,4 700,5 577.7 655.1 634.1 ' 613,5 590.4 567.7 544.4 T t | ] T o t a T T n Molecular AO Surface Surface Energy Energy (ergs) _(ergsT' 35,29 34,14 32,95 31 ,91 30,87 29,89 28.87 27,81 26.77 25,82 24,821 23.95 23 ,02 22.02 21.05 20 .2 19.39 13,65 17.85 16,98 16*171 15.44 1,15 1.19 1,04 1.04. 98 1.021 1. 06 | 1.04 95 1. 001 .87 .93 1.00 .97 .83 S3 .74 .80 .37 .31 ,73 61.05 60,96 60.83 60.85 60.87 60.95 60.99 50,99 61 .01 57,45 57,40 57,48 57,50 57.45 57.43 51,55 51,63 51.69 51.69 51 .62 51.61 51,68 1006,3 978,9 950 .1 925 .1 900 .0 876.4 851 ,3 824.8 798.5 774.7 749 ,1 727,3 703.4 677 .0 651.4 629,5 607.6 588.3 567 .0 543.0 520,9 501.0 1 4 7 . (b) from 60°C to 180°C, average ^jr - .088 and average t o t a l surface energy = 56.92 ergs. 2. for trans decalin , > . > (a) from -30°C to 50°C, average f f ~ • .106 and average t o t a l surface energy = 60.94 ergs. > (b) from 60°C to 110°C, average - .095 and average t o t a l surface energy » 57.45 ergs.- • • •• (c) from 120°C to 180° C, average M_ _ .080 and average t o t a l dt surface energy = 5 1 . 6 5 ergs. It w i l l be noted that the agreement between values of t o t a l surface energies for different temperatures i n any one temperature range, i s very good. The values of molecular surface energy (the Q(WV) of the Eotvos equation-), are tabulated and the variation with temperature i s shown on the accompanying graph. The curves are linear, and, as might be - expected, are very similar to those for |f v.s. t. The characteristic breaks are again evident, those for both isomers showing up at 50° - 60°C and 120° - 130°C. VII The latent Heats of Vaporization and Fusion. As a means of getting an approximate value for the latent heat of vaporization, the work of Walder?- was investigated. "vYe have the equation: W < ° j > . 3.64 '. K where AET = latent heat of vaporization per gram = density of l i q u i d at b o i l i n g point ^ = surface tension of l i q u i d at "boiling point 1. "Surface Tension and Surface Energy" by R. S. Willows & . E. Hatschek ( 3 r d ed.) 41-42, S6J3 UI : feu^j souj-Jng jDpg|o[Aj' V a l u e s . o f D 4 and ^ were o b t a i n ed by e x t r a p o l a t i o n , and AH, de te rm ined as i n the f o l l o w i n g t a b l e : c i s t r a n s .Kb AH^, i n c a l o r i e s per g r . 1§.»05 ,7638 76 ,5 14 ,99 . • .7433 73.4 These v a l u e s f o r A H T do not seem to be i n good agreement, however , w i t h v a l u e s c a l c u l a t e d f r om the C l a u s i u s - C l a p e y r o n e q u a t i o n . T h i s i s shown i n the f o l l o w i n g t a b l e , and may be due to a b n o r m a l i t i e s i n the v a l u e s o f % and ID a t the b o i l i n g p o i n t , t hus r e n d e r i n g the e x t r a p o l a t i o n an i l l e g i t i m a t e p r o c edu r e . t r a n s Temperature , Vapor P r e s s u r e A H V i n c a l o r i e s per g r . 191 .7 °C . 202 ,6°G . 74.276 cms. 101.47 cms. : 91 .0 17 X # 3 0« 187 .3°C . 59.710 cms. 80,485 cms. 54,9 The equa t i o n g i v e n by Walden, and i n v o l v i n g the l a t e n t heat o f f u s i o n , i s ; ( AH^)(1T) ± - 1 3 . 1 4 , •• • : - T f . • where AH^ = l a t e n t hea t o f f u s i o n pe r gram . IC « m o l e c u l a r we igh t Tj. - a b s o l u t e tempera tu re at f r e e z i n g p o i n t . following table shows the calculated values: CIS trans Freezing point (°C) AH^ . i n calories per gr. •-43.. 26° . 21 .8 - -.31.49° 23.0 VIII The Variation with Temperature of Viscosity. The graph of u v.s. t was drawn for each isomer, and the curves-, obtained appear perfectly regular and normal in shape. However., when * log u i s plotted against — (or, as shown on the accompanying graphs, when log u i s plotted against t--giving a curve form which i s similar to the other but concave to the r i g h t ) , we obtain for each isomer a cufve_ which i s made up'of f i v e different straight l i n e s . The - tran s i t i o n temperatures from one l i n e to another have been mentioned (see sections 1 and 2 ). ITow i t w i l l be recalled that f i v e isomeric forms for decalin have been, postulated by Wightman. It may be possible, then, that these f i v e forms are represented by this simple viscosity-temperature relationship. 1 Data for the v i s c o s i t y of benzene were next obtained and were plotted s i m i l a r l y against — . The resulting curve i s made of two linear portions, the change from one to the other being i n the region 30° - 40°G. Since the values of Eotvos constant :are not abnormally low for either benzene, or the isomers of decalin, such changes in slope cannot be attributed to changes i n association, 1. :J.. Phy. Chem. 34. 1599-1606. 50, but apparently are due to alterations in the molecular configuration, To investigate further this evidence from v i s c o s i t y , s.nd to l i n k up the vi s c o s i t y with other physical data, the work of 1 Batschinski was examined. He proposes the relation — s c(v - a) u where a and c are constants and v = spec i f i c volume. Hence 1 _ c — - ii - ac u D a straight l i n e for i v.s. i . u r> The plots for this equation are shown on the accompanying graph. It w i l l be noticed that the curve for cis i s r e a l l y made up of four straight lines separated at temperatures of -10° - 0°, 30° - 40° o o and 80 90 ; the curve fo r trans i s composed of three straight lines separated at temperatures of 0° - 10° and 50° - 60°. These tran s i t i o n temperatures do not agree very well with those previously given, and- no indication i s given of any change near 120°; however, the parallelism of the curves i s quite marked, and the fact that li n e a r characteristics are shown, proves the a p p l i c a b i l i t y of Batschinski' s relation;.,,. © e « © » 1. Batschinski, A., Zeit. physik. Ghem., 84, 643 (1913) 51 . ^ ^ i l M ^ o r _ t h e _ P l o t of B a t s n h i ^ T H . . CIS Temperature 1 2'' ( ° c •)• ; u t 1 , . U t • - 3 0 . 0 0 6.55 1.069 13 .70 1,102 -,•20.0.0' 9 .22 1.078 18.71 1.111 - i o . o o 13.55 1,087 24.50 1.121 0.00 18.28 1.096 31.24 1.130 1 0 . 00 23.95 1.106 38 .90 1.140 20 ,00 30 .09 1.115 47 .17 1.149 30 .00 37 .33 1 © X2 5 56 .02 1 © 159 40 .00 45 ,21 1.134 ': -:-6-6.27 1.169 &o:.oo 54 .02 1.144 77 .52 1.179 : '60.0.0:' 63 .65 1.154 89,37 1.190 70 .00 73,64 1.164 101.42 1.200 s o . o o 83.26 1.173 114.02 -L»2x1 / 90 ,00 94.79 1.184 127,06 1«223 100 .00 107 .91 !•• 195 141.44 1.234 110 .00 121.03 1.206 156.99 1.246 120 .00 134,79 1 © 21 *7 173.01 1.258 130,00 148.26 1.228 186,56 : 1.270 140 ,00 163,48 1.240 204.08 1.282 150 .00 178.19 1 © 25 2 217.87 •1.296 160.00 1 9 4 $ 3 o 1.265• , 236.97 1.309 170.00 210.04 1.273 257.73 1.324 180.00 — - — — ._ 227.38 1.291 277.01 1.338 5 2 . PART IV I n f o r m a t i o n Ob t a i n ed f rom F u r t h e r R e c t i f i c a t i o n and C r y s t a l l i z a t i o n . I n o rde r to s e cu re more o f each pure i somer f o r subsequent . • r e s e a r c h , i t was de c i d ed to f o l l o w aga i n the r e g u l a r p rocedu re o f r e c t i f i c a t i o n and c r y s t a l l i z a t i o n . Commencing w i t h the raw, . ....... unwashed d e c a l i n , the method was p r e c i s e l y the same as p r e v i o u s l y d e s c r i b e d . S i n c e , however , r a t h e r l a r g e y i e l d s were o b t a i n e d , . •. v. c e r t a i n d i f f i c u l t i e s were encounte red ( c h i e f l y i n the c r y s t a l l i z a t i o n t r e a tmen t s ) and i t i s f o r t h i s r e a son , and i n o rde r to p r e sen t s e v e r a l c o n c l u s i o n s t h a t t h i s work has been p r e s en t ed i n some d e t a i l . 1. R e s u l t s o f the R e c t i f i c a t i o n of C i s and Trans D e c a l i n . (ove r ) C h a r a c t e r i s t i c s o f Cha rge : (a) 2000 c . c . of Eastman Kodak d e c a l i n . (b) D|q- .. .8875 ( c ) = 1.47834 (d) app rox ima te c o m p o s i t i o n -r 24.5% t r a n s . " B o i l i n g P o i n t o f F r a c t i o n (°C) Volume of F r a c t i o n . ( c . c . ) Time f o r " F r a c t i o n ( h r s . ) Ra te of F r a c t i o n a t i o n ( c . c . / h r ) Index o f R e f r a c t i o n ( i P ) Approx ima te § o m n o s i t i o n { $ • : C 1ST) Bu l b 1 5 9 . 0 - 5 9 . 5 200 13 .5 14 .8 1.46983 1.9 Bu l b 2 5 9 . 5 - 6 1 . 2 227 14.5 15 .6 1.46993 2.2 Bu l b .3 6 1 . 2 - 64 . 3 . 331 23 .0 14 .4 1.47255 25.6 Bu l b 4 64 . 3 - 66 . 4 . 225 20 .0 • 11.25 1.47975 88 . 1 B u l b 5 6 6 . 4 - 6 7 . 9 528 50 .5 '•> io/5t ,;] 1.48118 >loo i: F i n a l r e s i d u e i n column bu l b =.400 c . c . Hence t o t a l l o s s d u r i n g r e c t i f i c a t i o n - 89 c . c . 54. R e c t i f i c a t i o n No. 2 C h a r a c t e r i s t i c s of Charge; Oc tober 6 - - 0 c t o b e r l 5 , 1958. ( } ItJ'^' •?1 * e C ! * l l n » c omp r i s i n g 1475 c . c . of raw i ^ t ? ? ? ^ ? ^ ^ 6 0 ^ 1 ? f 4 0 0 c ' c - o f bottoms of R e c t i f i c a t i o n No. 1 f 330 c . c . of b u l b ' 3 ' (b) D4 = 20 .8890 ( c ) IT| o = 1.47849 (d) approx imate c ompos i t i o n = 23% t r an s "Bo' i l ' ihg^Pbin ' t o f — F r a c t i o n (°C) Volume o f F r a c t i o n ( c . c . ) Time f o r F r a c t i o n ( h r s . ) Ra t e of F r a c t i o n a t i o n ( c . c . / h r ) Index of R e f r a c t i o n (Hio> Approx ima te Compos i t i on ! {% c i s ) Bu l b 1 Bu l b 2 Bu l b . 3 Bu l b 4 ". ; BM.b a 5"'4;l 5 9 . 5 - 6 0 . 2 6 0 . 2 - 6 2 . 0 62 . 0 - 64 . 9 64 , 9 - 67 . 8 , 67 .8 -68^ 370 500 345 405 • * 280 .] 24 .5 33 .0 3 0 . 5 ; 42 .5 29 ,0 { 15 . 1 ; 15 ,1 11 .3 9 .5 * • X',' , \\. . • • : ' : ; 9 - . * 6 v ' : ' : | 1.46988 1.47081 1.47804 1.48123 1.48128 2. 0 11 .2 73 .2 >100 >100 F i n a l r e s i d u e i n column bu l b » 440 c . c . Hence t o t a l l o s s d u r i n g r e c t i f i c a t i o n - 38 c . c . (a) 2053 c . c . o f h i g h c i s d e c a l i n c omp r i s i n g bu l b 5 of R e c t i f i c a t i o n No. 1; b u l b s 4 and 5 of R e c t i f i c a t i o n Ho.. 2j and 840 c . c . of h i g h c i s d e c a l i n f rom the c r y s t a l l i z a t i o n t r ea tmen t s of 1937-38. (b) D ,4 _ 20 .8965 ( c ) BP = 1.48118 (d) approx imate c ompos i t i o n = 100% c i s B o i l i n g P o i n t o f . F r a c t i o n (°C) Volume of F r a c t i o n ( c . c . ) Time f o r F r a c t i o n ( h r s . ) Ra te of F r a c t i o n a t i o n ( c . c . / h r ) Index o f R e f r a c t i o n App rox ima te Composition (% c i s ) Bu l b 1 67 . 1 - 67 . 6 100 I O . O 10 .0 1.48044 93 .0 Bu l b 2 6 7 . 6 - 6 8 , 0 330 32 .0 10 .3 1.48108 100 Bu l b 3 68 . 0 - 68 . 6 725 74 .5 9 .7 . 1.48108 100 Bu l b 4 68 . 3 - 68 . 8 370 38 .5 9 .6 . 1.48108 100 Bu l b 5 68.5^:68, , 160 17 .0 9. 4. 1.48108 100 F i n a l r e s i d u e i n column b u l b = 240 C . c . Hence t o t a l l o s s d u r i n g r e c t i f i c a t i o n = 128 c . c . I t appears f rom the above t h a t p r a c t i c a l l y a l l t h e i m p u r i t i e s were c o n c e n t r a t e d i n b u l b 1, and t h a t the r ema i n i ng bu l b s c o n t a i n ed c i s d e c a l i n o f v e r y h i g h p u r i t y . B e f o r e p r o c e e d i n g w i t h the t r a n s , t h e column was now washed t h o r ough l y by r e f l u x i n g i n i t f o r 5-6 hou r s a charge of d e c a l i n wh i c h had an app rox ima te c ompos i t i o n of 70% t r a n s . Th i s wash ing charge was made up o f two f r a c t i o n s o b t a i n ed f rom the R. D. Wa lker - -W. F . Seyer r e c t i f i c a t i o n s . 56 . R e c t i f i c a t i o n Uo . 4 November 3--November 9, 1938 C h a r a c t e r i s t i c s o f Charge ; (a) 1950 C . c . o f h i g h t r a n s d e c a l i n , c omp r i s i n g b u l b s 1 and 2 of R e c t i f i c a t i o n No. l j b u l b s 1 and 2 of - • • ' H R e c t i f i c a t i o n Ho. 2; and 653 c , c . of h i g h t r a n s •- ' ' d e c a l i n f rom the c r y s t a l l i z a t i o n t r ea tmen t s o f 1937-38 (b) D | 0 • .8700 ( c ) = 1.47008 (d) app rox ima te c ompos i t i o n = 96,6% t r a n s . B o i l i n g P o i n t o f F r a c t i o n (°C) I volume of F r a c t i o n ( c . c . ) Time f o r F r a c t i o n - ( h r s . ) Ra te of F r a c t i o n a t i o n ' ( c . c . / h r ) Index o f R e f r a c t i o n App rox ima te S O m p o s i t i o n {% t r a n s ) B u l b . 1 5 9 . 0 - 6 1 . 0 . Bu l b 2 •> 61 , 0 - 61 . 7 Bu l b 3 6 1 . 6 - 62 . 3 Bu l b 4 62 . 3 - 61 . 5 , Bu lb. 5. 6 1 . 5 - 5 1 . 0 85 378 460 220 360 6.5 30 .0 '. 43 .0 ' 23.5 34.5, 13 .1 12 .6 10 . 7 . .9.4 10 .4 1.46889 1.46933 1.46938 1.46933 1.46 9.43 >100 100 100 100 100 F i n a l r e s i d u e i n column b u l b => 390 c . c . . Hence t o t a l l o s s d u r i n g r e c t i f i c a t i o n = 57 c . c . The above t a b l e shows t h a t the c h i e f i m p u r i t i e s i n . our t r a n s c o n c e n t r a t e s were of the l o w - b o i l i n g p o i n t t y p e . T h e i r remova l appears to have been done q u i t e e f f i c i e n t l y , f o r b u l b s 2 ,3 ,4 and 5 a r e of the same approx imate c o m p o s i t i o n . 5 7 . 2. The F i n a l P u r i f i c a t i o n of C i s and Trans D e c a l i 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 ) Appa ra tu s and E x p e r i m e n t a l P r o c edu r e . E x c ep t f o r m inor changes , e v e r y t h i n g was the same as i n t he p r e v i o u s work . I n the - case of the c i s , i t was found t h a t the c r y s t a l l i z a t i o n s c ou l d be w e l l done by p l a c i n g our d e c a l i n i n an 800 c . c . g l a s s Dewar ( u s i n g an a i r wa l l ) : , and c o o l i n g the who le w i t h s o l i d carbon d i o x i d e i n a much l a r g e r Dewar. Hand s t i r r i n g was employed th roughout and no t r o u b l e w i t h s u p e r c o o l i n g was encoun te red . However, f o r t r a n s i t was n e c e s s a r y to evacuate the 800 c . c . Dewar i n o rde r to reduce to a minimum the r a t e o f heat ' t r a n s f e r . A l s o , .to reduce heat . .-v •,,'»* t r a n s f e r s t i l l f u r t h e r , i t was n e c e s s a r y to use mechan i c a l s t i r r i n g , s i n c e i t s use a l l o w e d the f o r m a t i o n o f a t h i c k l a y e r of c r y s t a l s * on the s i d e s of the Dewar. Such t rea tment f a v o r e d the phenomenon of s u p e r c o o l i n g , bu t no d i f f i c u l t y was e xpe r i en ced as s eed i ng was employed. . - • • . ' i (b) E x p e r i m e n t a l R e s u l t s f o r C i s D e c a l i n . The f r a c t i o n s • « • j s e l e c t e d f o r the p u r i f i c a t i o n were b u l b s 2 ,3 ,4 and 5 of R e c t i f i c a t i o n • No. 3 . U s i n g a c omb ina t i on of b u l b s 2,4 and o n e - h a l f o f bu l b 5,* • i t was found t h a t e i g h t s epa r a t e c r y s t a l l i z a t i o n s were r e q u i r e d , to o b t a i n the pure i somer and t h a t the v o l u m e t r i c y i e l d was 530 c . c . As b e f o r e the p roduc t was d r i e d u s i n g m e t a l l i c sod ium. Fo r t h i s m a t e r i a l , our f i n a l r e s u l t i s ; : . F . P . = - 4 3 . 2 9 t . 04°C . and NgO * 1.48113. ? The p u r i f i c a t i o n t r ea tmen t as a p p l i e d to a comb ina t i on o f b u l b 3 and the r ema i n i n g h a l f of bu l b 5, gave v e r y i n t e r e s t i n g 58. r e s u l t s . A f t e r f i v e c r y s t a l l i z a t i o n s , the m a t e r i a l c o u l d not be p u r i f i e d f u r t h e r and gave a cons t an t P. P. « - 43 . 08 °C . Th i s r e s u l t was o b t a i n e d a pp r o x ima t e l y t h r e e weeks a f t e r t he f r a c t i o n a t i o n o f the h i g h c i s d e c a l i n by R e c t i f i c a t i o n No. 3 . • Ten days a f t e r the d e t e r m i n a t i o n o f t h i s f r e e z i n g p o i n t , ano the r t e s t was run on t h e same m a t e r i a l . Th i s showed the cons t an t - • - f r e e z i n g p o i n t to have f a l l e n now to - 4 3 . 1 4 ° C . A g a i n , two months l a t e r , ano the r t e s t i n d i c a t e d the f r e e z i n g p o i n t to be s t i l l - 4 3 . 1 4 ° C . The v o l u m e t r i c y i e l d of t h i s m a t e r i a l was 590 c . c . T h i s work on c i s d e c a l i n c l e a r l y sugges t s the p resence o f some u n s t a b l e f o rm of c i s i s ome r . I t s p r e sence , p r edom ina t e l y i n - b u l b 3 , appears q u i t e r ema r kab l e , n o n e - t h e - l e s s f o r t u n a t e , and i t s c o n c e n t r a t i o n may be a t t r i b u t e d t o c a r e f u l r e c t i f i c a t i o n . As >> s t a t e d above, our f i r s t measurement on t h i s sample was made about t h r e e weeks a f t e r R e c t i f i c a t i o n No. 3 . Hence, c on ce r n i ng f u r t h e r - i n v e s t i g a t i o n a l o n g t h i s l i n e , i t seems p l a u s i b l e to suggest t h a t , f o l l o w i n g c a r e f u l r e c t i f i c a t i o n o f c i s d e c a l i n , f r e e z i n g p o i n t d e t e r m i n a t i o n s s h ou l d be commenced as soon as p o s s i b l e w i t h t he s epa r a t e f r a c t i o n s . ( c ) E x p e r i m e n t a l R e s u l t s f o r Trans D e c a l i n . As ment ioned p r e v i o u s l y , s e v e r a l p r e c a u t i o n s had to be taken i n o rde r to o b t a i n • optimum c o n d i t i o n s f o r t he c r y s t a l l i z a t i o n o f t r a n s d e c a l i n . Many t r i a l runs were made to i n v e s t i g a t e d i f f e r e n t e f f e c t s , and i t was f i n a l l y c onc l uded t h a t , when a d ry i c e c o o l i n g medium i s emp loyed , ' the use o f me chan i c a l s t i r r i n g and a w e l l evacuated Dewar (10^ - . 1,0*1": ; mms.) , a r e n e c e s s a r y . F u r t h e r , i t was demonst ra ted t h a t hand s t i r r i n g ! p roduces the same f r e e z i n g p o i n t as mechan i c a l s t i r r i n g , bu t i n the fo rmer case t he r a t e of c o o l i n g i s much g r e a t e r due to the c r y s t a l s 59 f o r m i n g w i t h i n the h u l k o f the l i q u i d and not b e i n g swept to t he s i d e s o f the f l a s k . U s i n g a comb ina t i on of b u l b s 4 , 5 and o n e - h a l f of bu l b 3 , a l l o f R e c t i f i c a t i o n No. 4 , i t was found t h a t s i x s epa r a t e c r y s t a l l i z a t i o n s were r e q u i r e d to o b t a i n the pure i somer and t h a t t he v o l u m e t r i c y i e l d was 500 c . c . However, u s i n g b u l b 2 and the o t he r h a l f o f b u l b 3 , twenty c r y s t a l l i z a t i o n s were required-, 1 t o o b t a i n the c on s t an t p o i n t , and the v o l u m e t r i c y i e l d was 135 c-. The f r e e z i n g p o i n t s of the. two ba t che s ag reed . F o r t r a n s d e c a l i n our f i n a l r e s u l t i s ? P . P. = - 3 1 . 1 6 + .04°C . and = 1.46954 60. PART V . A S tudy of; the E f f e c t of Heat on the Decompos i t i o n of C i s and Trans D e c a l i n . That hea t p roduced decompos i t i on i n the i somers of d e c a l i n • - seemed appa ren t f r om the d i s c o v e r y of t he p resence of u n s a t u r a t e d s i n the h e a t - t r e a t e d l i q u i d s wh i ch had undergone the measurements . • of d e n s i t y , s u r f a c e t e n s i o n and v i s c o s i t y . In the case of the c i s l i q u i d t he r e d u c t i o n o f a l k a l i n e po t a s s i um permangamate was q u i t e r a p i d ; i n the case of the t r a n s l i q u i d the r e d u c t i o n was a l s o obse rved bu t the t ime r e q u i r e d was much l o n g e r than f o r the c i s . In bo t h c a s e s , the r e f r a c t i v e i ndex remained t h a t of the pure i s ome r—one i n s t a n c e of the f a c t t h a t . r e f r a c t i v e i ndex i s . n o t a s e n s i t i v e p h y s i c a l p rope r t y - of these i s ome r s . I t would appear f rom t h i s , *then, t h a t a t the h i g h e r t empera tu res c i s and t r a n s d e c a l i n t end t o r e v e r t to t he u n s a t u r a t e d compounds f r om wh i ch they were fo rmed; and t h a t the tendency to do so i s much g r e a t e r f o r c i s than f o r t r a n s . S i n ce hydrogen wou ld be g i v e n o f f i n such a r e a c t i o n , i t i s q u i t e p o s s i b l e t h a t vapour p r e s su r e s r ead too h i g h when hydrogen i s p r e s e n t , b u t on the o the r hand i t i s p o s s i b l e t h a t t h i s may be compensated by the l o w e r i n g i n vapour p r e s s u r e f rom the s o l u t i o n of the u n s a t u r a t e d compound i n t h e pure d e c a l i n . A s l i g h t d i v e r g e n c e f r om the t r u e v a l u e s may a l s o be expec ted i n t hose o b t a i n e d f o r d e n s i t y , s u r f a c e t e n s i o n and v i s c o s i t y at the e l e v a t e d t empe r a t u r e s , and i t i s i n t e r e s t i n g to no te t h a t i t ,may - - be. t h i s d i v e r g en c e w h i c h i s r e s p o n s i b l e f o r the s l i g h t f a l l i n g o f f - - i n the cu r ves a t the h i g h e r t empe ra t u r e s . E x p e r i m e n t a l v e r i f i c a t i o n of the f o r m a t i o n of u n s a t u r a t e d s a ga i n i s i n d i c a t e d , t h i s t ime i n 61 the d a t a o b t a i n e d f o r c i s . As the author.? s work shows-, the-heat>>. • *v t r ea tmen t r e s u l t e d i n the c i s l i q u i d h a v i n g a h i g h e r d e n s i t y , s u r f a c e t e n s i o n and v i s c o s i t y , a t 20°C. than the pure c i s . p o s s e s s e s . Th is- - wou ld i n d i c a t e a p a r t i a l change a t l e a s t of the s a t u r a t e d c o n f i g U r a t i of pure c i s to t h a t of an u n s a t u r a t e d , f o r a s t udy of t he da t a o n -the u n s a t u r a t e d doub le r i n g (naph tha l ene ) i n d i c a t e s i t s p h y s i c a l p r o p e r t i to be h i g h e r t han t ho se o f t h e , s a t u r a t e d (as pure c i s o r t r a n s ) . To i n v e s t i g a t e more f u l l y the amount of s t r u c t u r a l change.- undergone, i t was d e c i d ed to f o l l o w the p r o d u c t i o n o f u n s a t u r a t e d s by f o l l o w i n g the change i n i o d i n e number. I t I s q u i t e : po s s i b l e - t h a t the f o l l o w i n g r e s u l t s do not i n d i c a t e u n s a t u r a t i o n on l y , as some s u b s t i t u t i o n may a lways t a k e . p l a c e d u r i n g the a b s o r p t i o n . Th i s s u b s t i t u t i o n wou ld be r e t a r d e d by the use of low t empe ra tu r e s . However, s i n c e d i f f e r e n c e s o n l y were d e s i r e d , a b s o r p t i o n a t 20°C. was deemed s u f f i c i e n t l y a c c u r a t e f o r the pu rpose , and a l l measurements were r e p r o d u c i b l e . (a) The E x p e r i m e n t a l P r o c edu r e . The method employed was e s s e n t i a l l y t h a t due to Hub1 w i t h the impo r t an t m o d i f i c a t i o n sugges ted by W i j s 1 . Two l i t r e s o f g l a c i a l a c e t i c a c i d were d i s t i l l e d tw i c e i n t he p r e sence o f p o t a s s i um permanganate i n o rde r to o x i d i z e any a l c o h o l or a c e t a l d e h y d e . The f i r s t 50 c . c . of each d i s t i l l a t e was r e j e c t e d . T h i s done, about 6.5 grams of pu re i o d i n e were d i s s o l v e d i n the p u r i f i e d a c i d , and' then washed and d r i e d c h l o r i n e . was passed i n t o the s o l u t i o n u n t i l the c o l o r changed f rom da rk brown t o r e d d i s h y e l l o w . That t h i s c o l o r change o c cu r r ed when the t i t e r of the s o l u t i o n was j u s t doub le t h a t of the i n i t i a l i o d i n e s o l u t i o n , 1. S u t t o n , " V o l u m e t r i c A n a l y s i s " , 1.0th e d i t i o n , page 412-415 . 62. was shown by t i t r a t i o n s w i t h s t anda rd sodium t h i o s u l p h a t e on-- - - the i n i t i a l i o d i n e and f i n a l c h l o r i n a t e d - s o l u t i o n s . The s t anda rd t h i o s u l p h a t e was p r epa r ed by V o l h a r d ' s method. Ch l o r o f o rm was used as s o l v e n t f o r the d e c a l i n ; a l s o used i n the t i t r a t i o n s - were ,a 10% s o l u t i o n of po t a s s i um i o d i d e and a f r e s h l y - p r e p a r e d - > - 1% s t a r c h s o l u t i o n . Each t i t r a t i o n was done i n a 250 c . c , c l e a n , P y r e x f l a s k p o s s e s s i n g a w e l l - g r o u n d g l a s s s t o p p e r . I n mak ing a d e t e r m i n a t i o n , a we ighed sample of the d e c a l i n (about .8 grams) was p l a c e d i n the f l a s k , d i s s o l v e d i n 10 • c . c . - o f c h l o r o f o r m , and 20 c . c . of the i o d i n e monoch l o r i de s o l u t i o n added. The f l a s k was co r ked and shaken w e l l and a l l owed to s t and f o r . 2 hours i n t h e da r k , a f t e r wh i ch t ime 10 c . c . of po ta s s i um i o d i d e s o l u t i o n and 100 c . c , o f wa te r were added. In o rde r to p reven t l o s s o f - i o d i n e by v o l a t i l i z a t i o n , the l i q u i d s were a l l o w e d to r un around, the w i d e - l i p p e d neck about the s t o ppe r , wh i ch was p a r t i a l l y removed to a l l o w the s o l u t i o n to en t e r the f l a s k . The excess i o d i n e was t i t r a t e d w i t h sodium t h i o s u l p h a t e , u s i n g s t a r c h i n d i c a t o r a t the end. The p r e p a r a t i o n of the d e c a l i n samples was done i n the f o l l o w i n g manner. About twen ty s m a l l t u be s , each w i t h a 2-3 c . c . b u l b on the end, were p r e p a r e d . A f t e r tho rough c l e a n i n g a s m a l l amount of pure* d r y d e c a l i n was i n t r o d u c e d i n t o each bulb.' The samples were then f r o z e n i n a " d r y i c e " medium and w h i l e i n t h i s c o n d i t i o n the tubes , were b lown on to a s e r i e s of T - tubes e x t end i ng v e r t i c a l l y outwards f r om a mother t ube . By c onne c t i n g one end of the mother tube t o a vacuum pump, the who le c ou l d be evacua t ed . Th i s done, the d e c a l i n was u n f r o z e n under vacuum to remove d i s s o l v e d a i r , and then hydrogen was adm i t t e d to the a ppa r a t u s . F i n a l l y , the d e c a l i n was once aga i n f r o z e n , the who le r e - e v a c u a t e d , and the s e r i e s of tubes s e a l e d o f f under vacuum. The hea t t r ea tmen t of the v a r i o u s samples was done emp loy ing a s m a l l c o n s t a n t - t e m p e r a t u r e h a t h , equ ipped w i t h thermometer, s t i r r e r and t h e r m o s t a t i c mechanism. (b) R e s u l t s of the Heat T rea tmen t s . P r i o r to the h e a t i n g , a n a l y s e s of t he pure c i s and t r a n s i somers p repa red i n 1937-38, i n d i c a t e d f o r each an apparen t i o d i n e number of .08 whereas f o r the pure i somers p r epa red i n 1938-39 the number was . 04 . These s m a l l i o d i n e numbers may be a t t r i b u t e d to s u b s t i t u t i o n . In c o n f i r m a t i o n o f the r e s u l t s o b t a i n ed w i t h a l k a l i n e - p o t a s s i u m • permanganate, a n a l y s i s of the h e a t - t r e a t e d c i s and t r a n s l i q u i d s f r om 1938 i n d i c a t e d appa ren t i o d i n e numbers of .36 and .15 r e s p e c t i v e l y . Heat t r e a tmen t o f t h e d e c a l i n samples i n the evacuated tubes f a i l e d to produce any u n s a t u r a t e d compounds. Thus, u s i n g the- pure d e c a l i n p r epa r ed i n 1937-38 , the i o d i n e number remained .08 even a f t e r 20 hours h e a t i n g a t 170°C. and.6 hours h e a t i n g a t 200°C- • T e s t s were c a r r i e d out a t 170°C. w i t h open tubes and i t was found t h a t a l t h o u g h s m a l l amounts o f u n s a t u r a t i o n were p roduced , the r e s u l t s were not r e p r o d u c i b l e f o r d i f f e r e n t t u be s . S l i g h t d i s c o l o r a t i o n s i n some of the tubes i n d i c a t e d t h a t the change i n i o d i n e number c o u l d be a t t r i b u t e d to m inu te amounts of o i l g e t t i n g i n t o the tubes f rom the ho t o i l b a t h . The aho've work on hea t t r ea tmen t s e r ve s to c l a r i f y s e v e r a l r e s u l t s o b t a i n e d i n t h i s r e s e a r c h on d e c a l i n : lw The i o d i n e numbers found to e x i s t f o r the h e a t - t r e a t e d c i s and t r a n s l i q u i d s of 1938, were p r obab l y due to s l i g h t amounts of o i l vapor g e t t i n g i n t o the open d e n s i t y tube ( v i s c ome t e r and s u r f a c e t e n s i o n tube were c l o s e d ) . O x i d a t i o n may have been r e s p o n s i b l e f o r p a r t o f t he change. , 2 . I r r e v e r s i b l e s t r u c t u r a l changes w i t h ou t the f o r m a t i o n of u n s a t u r a t e d s must occu r f o r c i s d e c a l i n a t e l e v a t e d t empera tu res T h i s ev i dence i s . o b t a i n e d f rom the changes wh i ch occu red i n the- , c l o s e d v i s c o m e t e r and s u r f a c e t e n s i o n t ube . As no ted i n p r e v i o u s c o n c l u s i o n s , such changes f o r t r a n s a r e r e v e r s i b l e . 3 . The r e s u l t s i n d i c a t e t h a t i f u n s a t u r a t ed s a re formed f r om c i s and t r a n s d e c a l i n a t t empera tu res up to 200°C. i n^c l o s ed t ubes , t he r e a c t i o n s a r e r e v e r s i b l e on c o o l i n g . 6,iT 1. Mohr, J , Phy s . Chem., 98, 315 (1918) 103, 316 ( 1922 ) . j 2. - Wightman, J . Chem. S o c . , 127, 1421 ( 1925 ) . I 3 . W i l l s t a t t e r & S e i t z , B e r i c h t e , 57B . , 683-4 (1924) . i 4 . Z e l i n s k y , N. 0 . & T u r o v a - P o l l a k , M. B . , B e r i c h t e , 58B . , I 1292-98 ( 1925 ) . | 5. " H u c k e l , W., Anna l en der Chemie, 441 , 1 ( 1925 ) . I 6. He r z , Z . P h y s i k . Chem. 101, 269 ( 1922 ) . I .-. 7. K i r k , L. M . , B. A . S c . , T he s i s ( 1935 ) . J 8. Man l ey , D . , B. A . S c . , T he s i s ( 1934 ) . | 9 . C o r n e t t , W. P . , B. A . S c . , The s i s ( 1935 ) . j 10 . Wa l ke r , R. D . , M. A . S c . , T he s i s ( 1937 ) . • ; . I 11* Seye r , W. E . , A s s o c i a t e P r o f e s s o r i n Chem i s t r y , U n i v e r s i t y o f ' B . C . | 12 . ' R i c h a r d s , Speyers & C a r v e r ; J . Am. Chem. S o c , 4 6 , 1196 (1924 ) . | 13 . B e n n e t t , R. , B. A . S c . , T h e s i s ( 1935 ) . 1 14 . Nemetz, H. & Henn i k e r , C . , M. A . S c . & B. A . ' S c . , T he s i s . h r e s p e c t i v e l y ( 1938 ) . v'• sj 1 5 . W i l l o w s , R. S. &. Ha t s chek , E.y. " S u r f a c e Tens i on and Su r f a c e Energy 1 ' | j . ( 3 r d e d . ) , 41 -44 . !|| 16 . Sugden, J . Chem. S o c . , 125, 1177 ( 1924 ) . f] 17 . B a t s c h i n s k i , A . , Z . P h y s i k . Chem., 84, 643 ( 1913 ) . jij 18 . S u t t o n , " V o l u m e t r i c A n a l y s i s " , 1 0 t h e d . , p. 412-415 . |j 

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