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Investigation of the specific heat of cis decahydornaphthalene Davies, George Francis 1939

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( i n # 7 INVESTIGATION OF THE SPECIFIC HEAT 0? CIS SECAHYDRONAPHTHALENE "by George Francis Davies, 3.A.Sc. Thesis submitted for the Degree of MASTER OF APPLIED SCIENCE in the Department of CHEMICAL ENGINEERING THE UNIVERSITY OF BRITISH COLUMBIA APRIL, 19.39 CONTENTS I . S e p a r a t i o n of the Pure C i s and Trans Isomers of De cahydronaphtha lene Page 1, I n t r o d u c t i o n /. 2 . P r e p a r a t i o n /• I I . S p e c i f i c Heat C a l o r i m e t e r 1 . Appara tus Page 4-2, P rocedure / / . I I I . S p e c i f i c Heat D e t e r m i n a t i o n Page 1. Ob se r va t i on s /6-2 . C on c l u s i o n s 22. ILLUSTRATIONS Page Diagram of C a l o r i m e t e r . . . SI Heater 7- ' Battery Cir c u i t ................ ....... ?. S p e c i f i c -Hea t -Tempe ra tu r e Graph . . . . . . . 2.1. .^Separation of the P u r e . C i s and Trans  Isomers of Decahyd ronaph tha l ene . I n t r o d u c t i o n . Under the d i r e c t i o n of D r . W.P. Seyer c o n s i d e r a b l e work has been done on the prob lem of s e p a r a t i n g and d e t e r -m i n i n g the p r o p e r t i e s of the i s ome r i c fo rms of decahyd ro -naph tha l ene . I t i s thought t h a t decahydronaphtha lene e x i s t s i n 5 s t e r e o - i s o m e r i c f o rms , the c i s and t r a n s forms b e i n g the l i m i t i n g p o s i t i o n s of the o the r t h r e e and t h e r e f o r e of g r e a t e r s t a b i l i t y . The f i r s t s u c c e s s f u l s e p a r a t i o n was a c comp l i shed i n 1936-37 b y . D r . W.P. Seyer and R.D. Wa l k e r . In 1937-38 ano the r s u c c e s s f u l s e p a r a t i o n was c a r r i e d out by L. Gou ld , , -(2) PI. Neraetz, C. Davenpo r t , and J . H e n n i k e r . The o b j e c t of the f o l l o w i n g r e s e a r c h was t o s epa r a t e more c i s and t r a n s decahydronaphtha lene and to c o n s t r u c t an appa ra tus f o r the d e t e r m i n a t i o n of the tempera tu re c o e f f i c i e n t s of the s p e c i f i c hea t s of the c i s and t r a n s i s ome r s . P r e p a r a t i o n . Commerc ia l d e c a l i n f rom the Eastman Kodak Co. was (1) Wa l ke r , R .D. M .A .S c . T h e s i s , 1937. (2) Gou l d , L .R . M .A .Sc . T h e s i s , 1938. used. The two isomers were separated hy repeated r e c t i f i -cation followed hy f r a c t i o n c r y s t a l l i z a t i o n . The apparatus and method used was that used hy R.D. Walker. The results of the 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 are as follows. R e c t i f i c a t i o n #1. Charge 2000 c.c. E.K. decalin D 4 0.8875 IT 1.48734 Comp. 24.5 Results. Bulh 1. Bulh 2. Bulh 3. Bulh 4. Bulb 5. Vol. 200 c.c. 227 c.c. 331 c.c. 225 c.c. 528 c.c. N 1.46983 1.46993 1.47255 1.47975 1.48118 Comp. 98.1% T 97.8% T 25.6% C 88.1% C 100% C Bottoms 400 c.c, , Re c t i f i c a t i o n # 2. Charge 1475 c.c. E.K. dec. as of 1. & 400 c.c. bottoms from 1. & 173 c.c. bulb 4. run l( a ) Trans last yr. & 330 c.c. of R.l. B.3 this y r . N 1.47849 D 0.886 Comp. 23% T. Results. Bulb 1. Bulb 2. Bulb 3. Bulb 4. Bulb 5. Vol. 370 c.c. 500 c.c. 345 c.c. 405 c.c. 280 c.c. ¥ 1.46988 1.47081 1.47804 1.48123 1.48121 Comp. 98% T 88.8% T 73,7% C 100% C 100% C Bottoms 44 0 c.c. Rec t i f i c a t i o n #3. Charge 2053 c.c. high c i s R . l , B.5.; R.2. B.4. & 5. & 840 c.c, of last year. ST 1.48118 D 0.8965 Comp. 100% C Results. Bulb 1. Bulb 2. Bulb 3. Bulb 4. Bulh 5. Vol. 100 c.c. 330 c.c. 725 c.c. 370 c.c. 160 c c . N 1.48044 1.48108 1.48108 1.48108 1.48108 Comp. 93% C 100% C 100% C 100% C 100% C Bottoms 240 c.c. R e c t i f i c a t i o n # 4 . H i gh T r an s . Charge R . l . 3 . 1 . & 2 . & f r a c t i o n s f rom l a s t y e a r . V o l . 1950 c ST 1.47008 D 0.8700 R e s u l t s . B u l h 1. Bu l h 2 . Bu l h 3 . Bu l h 4 . B u l h 5. V o l . 85 c . c . 378 c . c . 460 c . c . 220 c . c . 360 c . c . N * 1.46933 1.46938 1.46933 1.46943 Bottoms 390 c . c . C r y s t a l l i z a t i o n s . C i s . Bu l b 2 . & 4 . & h a l f of 5 . o 9 c r y s t a l l i z a t i o n s - f r e e z i n g p o i n t -43 .29 C. Bu l b s 3 . & h a l f of 5 . 6 c r y s t a l l i z a t i o n s - H i gh F . P . a l l o w e d t o s t a nd s e v e r a l months t o e f f e c t s t r u c t u r a l changes Re - run F . P . a f t e r -43 .14 C. Trans 20 c r y s t a l l i z a t i o n s - f r e e z i n g p o i n t -31.16°C . Summary of R e s u l t s . Isomer F r e e z i n g P o i n t °C D 0 C i s -43 .29°C 0.2 1.48113 Trans -31 .16°C 0.2 1.46968 S p e c i f i c Heat C a l o r i m e t e r . S i n ce i t was d e s i r e d not on l y t o de te rm ine the s p e c i f i c hea t of decahydronaphtha lene hut a l s o the tempera-t u r e c o e f f i c i e n t of the s p e c i f i c heat i t was ne ce s sa r y t o use a method of measu r i ng the a b s o r p t i o n o f hea t ove r a s m a l l t empe ra tu re r a nge . The a d i a b a t i c method of R i c h a r d s ^ and of (2) W i l l i a m s and D a n i e l l s v ' was c o n s i d e r e d the be s t f o r the pu r po s e . A s t r i c t l y a d i a b a t i c method was ne ce s sa r y i n o r d e r t o p r even t e v a p o r a t i o n o f the l i q u i d and t o p reven t a l l t r a n s f e r e n c e o f hea t t o the c o l d room. A c a l o r i m e t e r ( was b u i l t a c c o r d i n g t o the s p e c i f i c a t i o n s o f W i l l i a m s and D a n i e l l s . In b r i e f the method e n t a i l s the measurement of the quan t i t y - of e l e c t r i c i t y and the t ime ^requ i red t o r a i s e the t empe ra tu re of a known we i gh t of l i q u i d t h r o u g h a g i v e n tempera tu re i n t e r v a l® A p p a r a t u s . The appa ra tu s used i s i l l u s t r a t e d i n F i g . 1. -- The l i q u i d t o be measured was c on t a i n ed i n a c y l i n d r i c a l copper v e s s e l (A) 8 cm. h i g h and 6 cm. i n (1) R i c h a r d s : J". Am. Chem. Soc . . 3 1 , 1275 (1909 ) . (2 ) J . W . W i l l i a m s & F. D a n i e l l s : J . Am. Chem. Soc . 46 , 904 (1924 ) . 2_ diameter held in place by i n s u l a t e d suppo r t s i n an e n c l o s i n g vessel w i t h an a i r gap of 7 mm* between the two. The e n c l o s i n g v e s s e l (B) was also of copper 12 cm. h i g h and 8 em. in diameter f i t t e d w i t h a threaded cover of b r o n z e . A f l a t r ubbe r r i n g was .used as a gaske t between the c o v e r and the v e s s e l t o prevent leakage . A l i t t l e g rease was a l s o a p p l i e d t o the t h r e a d s . The cove r was p r o v i d e d w i t h an u p r i g h t tube f o r the s t i r r e r and w i t h s t u f f i n g boxes f o r the admission of the h e a t e r (C) and the thermocoup le (D) . The i n n e r s t i r r e r was . o f b r a s s and a t t a c h e d t o the main s h a f t by a sbe s t o s board t o p r e ven t t h e r m a l - c o n t a c t between the l i q u i d and the ou te r b a t h . A cap a t t a c h e d t o the upper s h a f t r o t a t e d i n the i l i q u i d of - the o u t e r b a t h so as to •make'-a s e a l and to- p reven t the movement of a i r . Such a p r e c a u t i o n was nece s sa r y t o p r e ven t the-- e v a p o r a t i o n of some of t he l i q u i d due to a i r currents. The mult iple thermal of 5 copper-constantan thermocouples was enclosed in a thin glass tube and con-nected w i t h a s e n s i t i v e ga l v anome te r . O i l i n the tube gave quicker response to temperature changes in the bath. The thermal was constructed as follows: "The pairs of wires were cut o f f and bared of insulation f o r 2 or 3 mm. at each end and soldered together. The wire used was size 32. Each j u n c t i o n was t hen i n s u l a t e d by -.' dipping separately into a f a i r l y thick rubber solution consisting of pure gum rubber dissolved in a mixture of benzene and ca rbon d i s u l p h i d e . The rubbe r was t h en a l l o w e d o t o s e t by h e a t i n g mode ra t e l y (about 1 0 0 ) , Two s e t s of f i v e the rmocoup les were made and the w i r e s were j o i n e d t o g e t h e r i n two h a l v e s w i t h f o u r l e a d w i r e s , by means o f wh i c h t he two h a l v e s may be connec ted e i t h e r i n s e r i e s o r i n o p p o s i t i o n . Hence t o t e s t the t hern ia ls no d e f l e c t i o n shou l d occu r when they a r e i n o p p o s i t i o n w i t h one end a t room tempera tu re and the o the r i n i c e w a t e r . The w i r e s were made i n t o a compact bund le by b i n d i n g w i t h s i l k t h r e a d and t hen e n c l o s e d i n the g l a s s t u b e . E n c l o s i n g the t h e rmocoup l e s - p r e s en t ed d i f f i c u l t i e s . I t - w a s found a lmos t i m p o s s i b l e t o I n s e r t t he t h e rma l i n a , S Y B - t u b e w i t h ou t b r e a k i n g the l e a d w i r e s . An " h " tube, was t hen t r i e d but usage caused e i t h e r breakage of t he w i r e o r g l a s s . The t ype shown i n the d i ag ram proved s a t i s f a c t o r y . The tubes were c o m p l e t e l y - f i l l e d w i t h o i l so t h a t r a p i d hea t t r a n s f e r f r om the g l y c e r i n e t o the t he rma l w i r e s would p reven t c on -d u c t i o n o f hea t f r om the i n n e r l i q u i d a l o n g the w i r e s . The h e a t e r was c o n s t r u c t e d by w i nd i n g r e s i s t a n c e w i r e a round a f l a t p i e c e of m ica as shown be l ow . TA/5 W/StZ The r e s i s t a n c e of t he h e a t e r was ahout 20 ohms f o r the wo r k i ng c o n d i t i o n s f o l l o w e d * - : I t was found ne ce s sa r y t o use rubbe r i n s u l a t e d w i r e s f o r the h e a t e r l e a d s t o p r even t s h o r t - c i r c u i t t h r ough t he copper t u b i n g . Cf cou r se any p a r t of the w i r e : t h a t was immersed i n the o r g an i c l i q u i d had " t o be f r e e o f i n s u l a t i o n . A l s o comple te immers ion of the h e a t i n g e lement was r e q u i r e d . The t empera tu re s were measured w i t h a p l a t i n u m r e s i s t a n c e thermometer and a h i g h p r e c i s i o n b r i d g e . W i l l i a m s and D a n i e l l s f ound t h a t the t r a n s f e r e n c e of hea t a l o n g a p l a t i n u m r e s i s t a n c e thermometer f rom the i n n e r c a l o r i m e t e r t o the room amounted t o as much as 0.35 c a l o r i e s per- 'minute-when the c a l o r i m e t e r was 15° above the , t empera tu re o f the room even though t he whole upper p a r t of the thermometer was immersed i n : the o u t e r - b a t h - a t t h e - same temper a t a r e as the i n n e r . : TM-s ; d i f f i c u l t y was e l i m i n a t e d by -p l a c i n g t he thermometer i n the ou t e r b a t h where no measured hea t l o s s e s can occur* The r e ad i n g s on the r e s i s t a n c e thermometer were t a ken on l y when the t h e rma l ga lvanometer :• r e g i s t e r e d - z e r o ' 1 . "--The t a n k f o r the ou t e r b a t h was c o n s t r u c t e d of sheet c oppe r . I t was packed i n a sbe s t o s c on t a i n ed i n a s t i l l l a r g e r c a n . The b a t h c o n t a i n e d 9 l i t r e s of g l y c e r o l i n wh i c h was d i s s o l v e d 20g . o f f e r r i c c h l o r i d e t o make i t an e l e c t r o -l y t i c c o n d u c t o r . I t was hea ted e x t e r n a l l y w i t h r e s i s t a n c e w i r e wound around the t ank and i n t e r n a l l y by passage of an a l t e r n a t i n g c u r r e n t d i r e c t l y t h r ough the l i q u i d b a t h f rom 2. st/c/A/r BOX I -3/l7~7E/fr C/ftC(//7~-the insulated calorimeter to the tank, A rheostat in the external heating c i r c u i t allowed e f f i c i e n t temperature control. The alternating current aided hy a motor driven s t i r r e r provided adequate agitation of the glycerine. Although the copper sides of the hath were being heated externally the temperature of the glycerine was only about one half a degree less than that of the wall. The current for t he inner heater was supplied by a 6 volt storage battery. The e l e c t r i c a l c i r c u i t i s shown in F i g . 2 . The potential difference across the heater was measured with a sensitive potentiometer, the voltage being reduced through a shunt box to a convenient quantity for measurement. The current through the heater was measured by the potential drop across a 1 ohm standard resistance, Procedure« A g i v en volume (155 c . c . ) of the l i q u i d to he i n -v e s t i g a t e d was a c c u r a t e l y weighed and i n t r o d u c e d i n t o the c a l o r i m e t e r . Measured amounts of e l e c t r i c a l energy were passed t h r ough the h e a t e r f o r d e f i n i t e t ime i n t e r v a l s . The h e a t i n g of the ou t e r h a t h was r e g u l a t e d so as t o keep the t h e rme l a lways on ze ro thus e n s u r i n g a d i a b a t i c c o n t r o l . A s i n g l e sample of l i q u i d was used f o r the e n t i r e t empera tu re r a nge . The f o l l o w i n g p rocedure f o r the r e c o r d i n g of obser v a t i o n s was ne ce s sa r y i n o rde r t h a t the appa ra tus c ou l d be c o n t r o l l e d by one p e r s o n . 1. The h e a t i n g c i r c u i t was c l o s e d w i t h the dummy "hea te r i n the c i r c u i t , t h i s b e i n g l e f t i n f o r 20 t o 30 m i n s . t o a l l o w the i n i t i a l h i g h E .M .P . f r om the b a t t e r y t o come t o e q u i l i b r i u m . 2 . The c u r r e n t was then d i v e r t e d i n t o the r e a l h e a t e r and the s t op wa t ch s t a r t e d . A d i a b a t i c c o n t r o l was then commenced by o b s e r v i n g the t he rme l and p u t t i n g i n or p u l l i n g out the two ba t h h e a t i n g sw i t c he s as r e q u i r e d t o keep the t he rme l on z e r o . U s u a l l y the e l e c t r o l y t i c h ea t e r ' c o u l d be l e f t i n and the o u t s i d e h e a t e r on l y o p e r a t e d . 3 . The P .D . a c r o s s the hea t e r and the c u r r e n t t h r ough i t , t o g e t h e r w i t h the r e s i s t a n c e of the p l a t i n u m r e s i s t a n c e thermometer were measured and the t ime of measurement n o t e d . In the case o f the tempera tu re the t ime had t o be t o the n ea r e s t second . I t was found b e t t e r t o l e a v e t he l a s t ddsal or 4 t h de c ima l p l a c e of the r e s i s t a n c e b r i d g e on 0 and t o t ake the t ime when a r e s i s t a n c e r e a d i n g i n the 3 rd d e c ima l o c c u r r e d . In t a k i n g t empera tu re s 3 or 4 r e ad i ng s were t a ken as c l o s e t o g e t h e r as p o s s i b l e , t h en a f t e r the l a p s e of the d e s i r e d t ime 3 or 4 more were t aken a l s o as c l o s e t o g e t h e r as p o s s i b l e . Th i s enab led a number of heat i npu t c a l c u l a t i o n s t o be made about the mean t empe r a t u r e . Lag i n r e c o r d i n g the t empera tu re was t hus m i n i m i z e d . The change i n r e s i s t a n c e f o r a d e f i n i t e i n t e r v a l of . t ime was o b t a i n ed by p l o t t i n g R a g a i n s t temp. For a 5 to 10° i n t e r v a l a s t r a i g h t l i n e r e s u l t e d . The r e a d i n g s of the thermometer had t o be c o r r e c t e d ' f o r Itf, R, NZ, and RZ a f t e r the r u n . Fo r the sake of b r e v i t y i t i s i n a d v i s a b l e t o i n -c l ude a l l t he r e ad i n g s of each run i n t h i s p ape r . However, t he f o l l o w i n g i s a t y p i c a l example of the method and r e a d i n g s . Run # 2 2 . 50°C. Time Cu r r en t I . R e s i s t a n c e 22 :47 2 .9620 25 :10 2 .9690 . 26:37 2.9730 28:30 2 .9780 29:00 5.7036 00:00 0.32296 3:15 2.9910 5 :15 2.9970 7 :05 3.0020 11:45 3.0150 12 :30 5.7035 14:39 3.0230 17 :07 3.0300 18:38 1 3 .0340 19 :00 5.7038 20:00 0.32294 /3-The a c c u r a t e d e t e r m i n a t i o n of the wate r e q u i v a l e n t of the c a l o r i m e t e r p r e sen t ed d i f f i c u l t y . • An approx imate va l t i e was ob t a i n ed by we i gh i n g or e s t i m a t i n g the we igh t of the p a r t s of the c a l o r i m e t e r wh i ch abso rbed some of the measured h e a t , and then c a l c u l a t i n g the hea t c a p a c i t y . C a l c u l a t i o n of Water J S g u i v a l e n t Subs tance Wt. Sp . H t . H t . Cap. G . / d eg . Copper 278 .1 .092 107 G l a s s 5.4 ,165 3.7 M i c a 2 .9 .208 2 .5 B r a s s 18 .9 .094 7.4 O i l .6 .5 .12 120.77 Th i s i s on l y an e s t i m a t e . The wate r e q u i v a l e n t was ob t a i n ed by u s i n g pure benzene and t o l u e n e i n the c a l o r i m e t e r u s i n g da t a f rom the I n t e r n a t i o n a l G r i t i c a l Tab l e s f o r the r e s p e c t i v e s p e c i f i c h e a t s . The r e s u l t s a r e as f o l l o w s : Benzene . :Temp. Wt. of l i q u i d Sp . H t . T o t a l Input 3 Input W.E. 30°C 137.26 g.. 1.732 j / d e g . 385 238 147 30 O C 138.7 1.732 386 241 145 30°C 138 .3 1.732 384 240 144 30°C 134.9 1.732 380 234 146 Ave . 145.5 To l uene . Temp. Wt. of l i q u i d Sp . H t . T o t a l Input 3 Input W • IS» 30°C 135.9 1.70 j / d e g . 376 231 145 30°C 135 .0 1.70 \ 373 230 '. 143 30°C 130.5 1.70 372 222 j 150 30°C , 1 3 7 . 5 1.70 375 234 ] 141 30°C 137.4 1.70 375 234 141 Ave . 144 These were the p u r e s t l i q u i d s o b t a i n a b l e of known s p e c i f i c h e a t . S i n ce the ob j e c t of the i n v e s t i g a t i o n was p r i m a r i l y t h a t of s t u d y i n g the v a r i a t i o n of s p e c i f i c hea t w i t h t empe ra tu r e r a t h e r t han the a b s o l u t e v a l u e of the s p e c i f i c hea t a r e f e r e n c e wate r e q u i v a l e n t was ob t a i ned f rom these ' f i g u r e s r a t h e r t h an a c o r r e c t water e q u i v a l e n t . F u r t h e r i n v e s t i g a t i o n of t he wa te r e q u i v a l e n t was om i t t ed due to p r e s s u r e o f t ime as i t wou ld have been ne ce s sa r y t o use a pure l i q u i d of l ow vapour p r e s su r e and known s p e c i f i c heat and no such l i q u i d was a v a i l a b l e . The benzene used had been r e c r y s t a l l i z e d and was pu r e r t han the t o l u e n e . The average wate r e q u i v a l e n t found f r om the benzene runs was t a ken as the b a s i c v a l u e . i . e . , 145 .5 j o u l e s pe r degree a t 30°C. Th i s i s n o t i c e a b l y h i g h e r t han the e s t ima t e d wa te r e q u i v a l e n t . The d i f f e r e n c e i s thought t o be due t o heat absorbed by s o l d e r , c o r k , and i n -s u l a t i n g m a t e r i a l wh i ch c ou l d not be e s t i m a t e d . The agreement between benzene and t o l u e n e f a vou r ed the h i g h e r v a l u e . U s i n g a wate r e q u i v a l e n t of 145 .5 j o u l e s / d e g r e e a t 30°C the s p e c i f i c hea t of C P . ca rbon t e t r a c h l o r i d e was i n v e s t i g a t e d . Two ' runs were made a t 30°C. R e s u l t s : 1 . Sp . H t . GC1 4 ~ .868 j o u l e s / d e g . 2. Sp . H t . CC1 4 = .867 j o u l e s / d e g . The v a l u e g i v e n i n the c r i t i c a l t a b l e s = .837 j o u l e s pe r degree a t 30°C. Th i s a g a i n f a vou r ed a water e q u i v a l e n t i n the ne ighbourhood of 145 j o u l e s / d e g . In consequence a b a s i c wate r e q u i v a l e n t 145.5 j o u l e s / d e g . a t 30°C was used i n t he subsequent decahydronaph tha lene i n v e s t i g a t i o n s . The change i n wa te r e q u i v a l e n t w i t h tempera tu re a l s o p r e s en t e d d i f f i c u l t y . The change i n t he c a l c u l a t e d e q u i v a l e n t 120.77 was de te rm ined by c a l c u l a t i n g the i n c r e a s e f o r a 10° r i s e i n t e m p e r a t u r e . T h i s was t hen put on a b a s i s of 1 4 5 . 5 . R e s u l t i n g v a l u e was an i n c r e a s e of .5 j o u l e s per degree f o r each 10 degree r i s e i n t e m p e r a t u r e . T h i s ag reed q u i t e w e l l w i t h the 0 .3 j o u l e s per degree used i n the o r i g i n a l c a l o r i -meter of W i l l i a m s and D a n i e l l s . I t was n o t i c e d t h a t i n c a l i -b r a t i n g the i n s t r umen t the graphs of temp. v s . t ime were p a r a l l e l i r r e s p e c t i v e of the l i q u i d u s e d . T h i s a r i s e s f rom the f a c t t h a t the hea t c a p a c i t y per u n i t volume of most , l i q u i d s i s a c o n s t a n t . App rox ima t e l y the same volume was used i n each c a s e . Water was a l s o t r i e d as a c a l i b r a t i o n l i q u i d but d i d not p rove s a t i s f a c t o r y due t o c o r r o s i o n of the ba re h e a t i n g w i r e . A l s o the h i g h s p e c i f i c heat of water gave o p e r a t i n g c o n d i t i o n s t h a t were not p a r a l l e l w i t h those of the o r g an i c l i q u i d s . /6. Obse r v a t i oris f o r C i s Pe cahyd ronaph tha l ene . Fain # 19 . Wt. of C i s 143.083 g . Temp. Re s . I n t . F a c t o r 1000 s e c . Temp. I n t . P .D. I . Sp . H t . 2.5° 2 .7770 2 .7323 1.02 4 .54° 5.536 - .3160 1.677 30° 2 .8403 2 .7961 1.02 4 .51 5.5362 .3159 1.683 36° ' 2 . 8873 2.8427 1.02 4 . 55 5.537 .3158 1.667 . 40° ; 2 .9365 2 .8921 1.02 4 .53 5.537 .3157 1.675 ; 45° ! 2 . 9795 2 .9353 1.02 . 4 . 51 5.538 .3156 1.687 50° 3 .0155 2 .9715 1.02 4 .49 5.5377 .3155 1.689 Wt. of C i s 143.038 g . 1 Temp. Re s . I n t . F a c t o r 1000 s e c . Temp. I n t . P .D. I . Sp. H t . 30° 2.8385 2,7910 1.02 4 .845 5.7435 .32805 1.702 35° 2 .8861 2 .8385 1.02 4 .855 5.7443 , .3280 1.694 40° 2,9429 2.8957 1.02 4.814 5.7440 .32797 1.715 45° 2 .9841 2,9363 1.02 4.886 5.7443 .32794 1.673 50° 3.0230 2.9753 1.02 4 .865 5.7446 .32790 1.683 55° 3.0857 3 ,0393 1.02 4 .733 5.7443 .32780; 1.750 i: "0 ' 60 3.1331 3.0873 1.03 4 .717 5,7440 .32767 1.762 ;65° : 3.1867 3 .1411 1.03 4 .697 5.7435 .32760! 1.771 170° 3.2312 3.1860 1.04 4 ,701 5.744 1.766 75° . , 3.2852 3.2410 1.04 4 .597 5.7435 .3275 1.828 80° \ 3 .3290 3 .2851 1.04 4.566 5.743 .3274 1.844 Run # 21 Wt. of C i s 141.934 g . Temp, Re s . I n t . F a c t o r 1000 s e c . Temp. I n t . P.I). I . Sp. H t . 30° 2.8414 2 .8221 •1.02 1.969 (400 s . ) 5.725 .3243 1.632 35° 2 .8920 2.8438 1.02 4 .916 5.7267 .32435 1.635 40° 2 .9390 2.8915 1.02 4 .845 5.7268 .32435 1.673 45° 2.9767 2.9302 1.02 4 .743 5,7260 .32425 1.737 , 50° 3,0119 2 .9650 1.02 4.784 5.7250 .32420 1.701 ; 55° 3.0892 . ,3 .0431 1.02 4 .702 5.7240 ; .32415 1.746 : 60° 3.1354 3 .0900 1.03 4.676 5.7230 .32410 1.760 j - _o i DO 3.1893 3.1439 1.03 4.676 59722o ,32400 1.758 70° 3,2266 3.1818 1.04 4 .660 5.7210 .32387 ; 1.762 75° 3.2859 3 .2420 1.04 4 .566 5.7204 .32385 1.818 80° o»32 32 3.2798 1.04 4.514 5.7185 .32385 1,847 Run # 2 2 wt . of C i s 141.934 g . Temp. Re s . I n t . F a c t o r 1000 s e c . Temp. • I n t . P.D„ I . -Sp. H t . 35° 2.8996 2.8518 1,02 4.876 5.705 .3232 1.637. 0 40 2.9371 2,8903 1.02 4.774 5.704 .3230 1.691 45° 2.9841 2.9372 1.02 4.784 5.704 .3230 1.683 50° 3.0180 2.9713 1.02 4 .763 5.704 © 3*2 3 0 1.693 55° 3.0851 3.0396 1.02 4 .671 5,704 .3229 1.750 60° 3.1244 3.0792 1.03 4 .656 5.704 .3229 1.751 65° 3 .1881 3.1429 1.03 4.6 56 5.703 .3229 1.750 Run # 23 Wt. of C i s 141.934 g . 25° 2.7953 2.7483 1.02 4.794 5 .663 .3206 1.645 30° 2.8432 2 .7960 1.02 4.814 5 .663 .3206 1.702 35° 2 ,8880 2 .8415 •1.02 4 .743 5 .663 .3206 1.685 4 0° 2.9440 2.8971 1.02 4.784 5,664 .3205 1.645 45° 2.9767 2.9302 1.02 4 .743 5.664 .3205 1.666 50° 3.0141 2 .9681 1.02 4 .692 5.664 .3205 1.694 S p e c i f i c Heat i n J o u l e s per degree per gram, 20. Temp. Run #19 #20 #21 #22 #23 Ave . 25° : 1,677 1.645 1,661 30°- 1.683 1.702 1.632 1.702 1.680 35° 1.667 1.694 1.635 1.637 1.685 1.663 4 0 ° 1.675 1.715 1.673 1.691 1 . 6 4 5 X 1.689 45° 1.687 1.673 ...1,737 x 1,683 1 . 6 6 6 X 1.681 ; 50°; 1.689 1.683 1.701 1.693 1.694 1.692 ; 55° 1.750 1.746 1.750 1.749. 60° 1.762 1.760 1.751 • 1.758 65° 1.771 1.758 1.750 1.762 70° 1.766 1.762 1.764 75° 1.828 1.818 I«823 80° 1.844 1.847 1.846 i 1 i 1 < • - l s .' " 1 • • > C o n c l u s i o n s . Prom the d a t a i t w i l l be n o t i c e d t h a t the v a r i a t i o n i n the v a l u e s of the s p e c i f i c hea t be low 45°C i s much g r e a t e r t han the v a r i a t i o n above . Th i s may be due t o sharp changes i n the v i s c o s i t y a t low t empe ra tu re s .^ 1 ^ A l s o the l a g i n the a b s o r p t i o n of heat by the v a r i o u s p a r t s of the c a l o r i m e t e r was p r obab l y g r e a t e r a t lower t empe r a t u r e s . I t was no ted t h a t o the movements of t he thermocoup le were f a s t e r above 45 or 50 t h an t hey were be l ow . The v i s c o s i t y of the g l y c e r i n e i n the b a t h may a l s o have had some e f f e c t on the tempera tu re measure-ment due t o non - un i f o rm h e a t i n g when more v i s c o u s . The s l ope of the curve i n the graph of Sp. H t . v s . temp, f o r c i s decahydronaph tha lene i n d i c a t e s t h a t a t r a n s i t i o n t a ke s p l a c e i n the ne ighbourhood of 50°C. Th i s i s to b e . e x -pec t ed f rom s i m i l a r changes a t 50° i n the s u r f a c e - t e n s i o n -tempera tu re curve f o r the c i s i s ome r . ( "O U n f o r t u n a t e l y the c a l o r i m e t e r i n u s e , a l t h o u g h s u i t a b l e f o r the measurement of the t o t a l heat c a p a c i t y of a l i q u i d , was not s u i t a b l e f o r d i s t i n g u i s h i n g between the a c t u a l s p e c i f i c heat and the l a t e n t heat of t r a n s i t i o n . To do t h i s i t wou ld be nece s sa r y to b u i l d a s i m i l a r a p p a r a t u s , w i t h the tempera tu re of the i nne r l i q u i d measured d i r e c t l y i n s t e a d of by means of the thermocoup le and ba th thermometer . The c o n t r o l of the i n s i d e h e a t e r and ba t h (1) Davenpor t , C H . E . A . S c . T h e s i s , 1938. "heating equipment would also have to he a great deal more sensitive so that discontinuities in the temperature-time curves could he followed without superheating the decalin during t r a n s i t i o n . Actually the tr a n s i t i o n should take place without any r i s e in temperature. When a large volume of l i q u i d , as in the above case, is used i t i s increasingly d i f f i c u l t to effect t r a n s i t i o n without imparting heat to the l i q u i d already transformed. The Sp. Ht.-temperature curve indicates that tran-s i t i o n started at approximately 5 0 ° C and continued to about 70°C. The area between the Sp. Ht. curve and the lines AB, BC is a measure of the heat of t r a n s i t i o n . Prom the graph the value of the heat of t r a n s i t i o n is about 0.85 joules per gram. In regard to the numerical value of the Sp. Ht. the extrapolated value from the curve for 15°-18°C i s 1.661 j oules per degree. This compares favourably with the value 1.653 joules/degree given for c i s decahydronaphthalene at 15°-18°C in the International C r i t i c a l Tables. Note: Mica as a base for winding the heating element wire proved to be unsatisfactory when used with decalin at tempe-o ratures above '80 due to c a p i l l a r i t y effect and spreading of the mica sheets. BIBLIOGRAPHY Wa l k e r , R. D. , M .A .S c . The s i s 1937. Gou l d , L. R . f M .A .S c . The s i s 1938. R i c h a r d s , J . Am. Chem. So c . 3 1 , 1274 ( 1909 ) . J . W. W i l l i a m s & P. D a n i e l l s , J . Am. Chem. Soc . 46 , 904 ( 1924 ) . Davenpo r t , C. H . , B . A . S c . The s i s 1938. 

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