A Study of the Bromination of Paracresol in Water Solution and in Hydrochloric Acid Citation Jenkins, Grant Vincent (1924) A Study of the Bromination of Paracresol in Water Solution and in Hydrochloric Acid. Bachelor's thesis, California Institute of Technology. doi:10.7907/V00G-WY31. https://resolver.caltech.edu/CaltechETD:etd-04262004-140048 Abstract No Abstract. Item Type: Thesis (Bachelor's thesis) Subject Keywords: General Course ; Chemistry Degree Grantor: California Institute of Technology Division: Chemistry and Chemical Engineering Major Option: Chemistry Thesis Availability: Public (worldwide access) Research Advisor(s): Unknown, Unknown Thesis Committee: None, None Defense Date: 1 January 1924 Record Number: CaltechETD:etd-04262004-140048 Persistent URL: https://resolver.caltech.edu/CaltechETD:etd-04262004-140048 DOI: 10.7907/V00G-WY31 Default Usage Policy: No commercial reproduction, distribution, display or performance rights in this work are provided. ID Code: 1506 Collection: CaltechTHESIS Deposited By: Imported from ETD-db Deposited On: 29 Apr 2004 Last Modified: 03 Oct 2019 23:08 Thesis Files Preview PDF (Jenkins_gv_1924.pdf) - Final Version See Usage Policy. 697kB Repository Staff Only: item control page

the of BROMIEJATION of PARA-CRESOL IN WATER SOLUTION and in HYDROCHLORIC .ACID Thesis by Grant V . Jenkins I n p a r t i a l f u l f i l l m e n t of t h e requirements f o r t h e degree o f Bachelor of Science i n General Science C A L I F O ~ I AINSTITUTE OF TECHNQLOGY Pasadena, California Pap-e One A STU3Y OF THE B R O M I N A T I X V O F PARA-CRESOL I N TATER S O L U T I O N AKD I N HYCROCHLORIC ACIC . ALSO C I S C T J S S I O N O F THY E R O L U E A T I O Y OF FXENOL IN WkLTER SOLUTION. References: +:..--g- No r e f e r e n c e s were a v a i l a b l e on t h e bromination o f phenol snd c r e s o l i n Any c r e d i t f o r t h e water s o l u t i o n . e-onception of t h i s p r o c e s s , and i t e f u t u r e value must go t o M r . H. J . Lucas, of t h e C a l i f o r n i a I n s t i t u t e of Technology. The d e s i g,.-n of t h s c p p z r a t u s , and t h e msthods used i n overcoming d i f i ' i c ~t~i el s , a r e products of t h i s laboratory. On the t h e o r y o f e l e c t r o n displacement, and t h e e f f e c t of s i d e groups on t h e brornination of the benzene r i n g , i t was proposed t o s t u d y the bromination of p a r a - c r e s o l i n f i e u t r a l , and i n s c i J s o l u t i o n . Pre- l i m i n a r y m r k was f i r s t done on the brornination of phenol i n water s o l u t i o n , mainly t o master t h e t e c h n l c and overcome d i f f i c u l t i e s encountered. The f i r s t c o n s i d e r a t i o n of i n t e r e s t was t o determine whether t h e presence of c o n c e n t r a t i o n of H+ a f f e c t e d t h e @ large I n benzene, C6H6, we have t h i r t y e l e c t r o n s which have t o be arranged i n o c t e t s around t h e s i x carbon atoms. Ths s i m p l e s t a r r a n g e - ment seems t o be a r i n g with t h e s i x carbon atoms i n c o n t a c t mith a t r i p l e e l e c t r o n c o n t a c t betl.!?sn each two. Armstrong andBayer c e n t r a l theory T h i s arrangement seems t o i n t r o d u c e the l e a s t s t r s i n i n the molecule, and g i v e s a symmetrical placemsnt of t h e e l e c t r o n s , Kekules ' conception o f t h e molecule c o n s i ~ t soP t h r e e s e t s of p a i r s of carbon a t o r - s , t h e c e l l s i n e a c h p a i r h a v i n g four- f o l d c o n t a c t with ezch o t h e r , b u t only double c o n t a c t with the neighb o r i n g pa ips. The r a t e of s ~ b s tt u i t i o n , ranging Kekule Ring from s t r o n g l y ( + ) t o s t r o n g l y (-1 i s : OH, NH2, NO f o l l o w o r precede CH3. 2 C1, I , B r , CH3, C02H, $03H, w i t h some q u e s t i o n whether I should I n n e u t r a l s s o l u t i o n , and beczuse of the comparative ini'luences of t h e CH3 and the OH, when p a r a - c r e s o l i s brominated xit'n o n l y t h e required m o u n t of bromine f o r one s u b s t i t i l t i o n i n t h e r i n g , i t i s faun$ that Faye Three p r a c t i c a l l y a l l of t h e r e p l a c e m e n t i s i n t h e 3- p o s i t i o n . I n o t h e r words, t h e combined e f f e c t o f t h e OH i n E t t r a c t i o n , , and t h e CH3 i n r e p u l s i o n , c a u s e s t h e PR t o s u b s t i t u t e Tor H i n t h e 3- p o s i t i o n . Due t o t h s tenc?eccy of t h e phsnolz t o form s a l t s i n s t r o n g a c i d s o l u t i o n b y a d d i n ,g- H' t o t h e OH, i t was t h o u g h t p o s s i b l e t h a t a b r o m i n a t i o n c a r r i e d on i n 1 2 N . H C 1 would g i v e d i f f e r e n t r 4 s u l t s t h a n a bromination i n n e u t r a l ~ o l u t i o n . With a d 2 i t i o n a l H+ a4d3d on t h e OH i t s e f f e c t of a t t r a c t i o n should be l z s s e n e d , and more F r wo.llC g o t o t h e 2- p o s i t i o n . para-cresol The r e s u l t ? w i l l be d i s - cussed l a t e r . A f t e r t h e t e c h n i c was n . a s t e r e 8 , and a n a p p a r a t u s "signed t h a t would make c o n t i n u o u s e x t r a c t i o n w i t h a soIver,t p o s s i b l e , f o u r b r o m i n a t i o n s wew ca-pied o u t . I n e a c h cslse 50 grams of p a r a - c r e s o l was used. TWO of t h e brorriinztions wer3 c a r r i e d o u t i n n e ~ . t r a ls o l u t i o n of w z t e r ; the o t h e r two were done i n 1 2 N . h y d r o c h l o r i c a c i d . I n each the c a s e ei? s o l u t i o n of the k r ~ n i n tse d pl3oc7ucts in e t h e r w3re r2risd o v e r anhydrous sodium s u l f a t e and d i s t i l l e r ' i n vacuo. The amounts o f n 4 a t e r i a l s u s e d , t i m e , t s m p 2 r a t u r n , lei2gth of e x t r a c t i o n , and t h e r e s u l t s of t h e c i i s t i l l a t i o n a r e g i v e n a t t h e back p m t of t h i s p a p e r . Fage Four KO C e f i n i t e r e s u l t s can be ?.educed from t h i s experiment. I n t h e f i r s t p l a c e consic'erable d i f f i c u l t y w 2 s experienced i n g 2 t t i n g good s e p e r a t i o n s . V i t h the bulk of t h e brominated Sroduct d i s t i l l i n g a t 104O a t 20 mm, and ~ 5 t ho n l y a snlall f r a c t i o n p r e s e n t a t a t h e h i g h e r b o i l i n g p o i n t s , i t would be unwise t o ?raw c o n c l ~ sojn s on t h e bromination i n the 2- p o s i t i o n which i s r5presented & . b y the h i g h e r b o i l i n g products, rrom the 3 a t z a t hand. &any more b r o ~ i n e t i o n sw i l l h a v e t o be c a r r i e d on b e f o r e a conclusion can be drawn. Also, u n t i l a method of a n a l y s i s of t h s b r o r c r e s o l compounds is found, no a c c u r a t e d a t a c a p be o b t a i n 5 d . A l s o , u n t i l a preceedure i s found b y which t h e brom-crescl compoumds can be changed i n t o o t h e r d e r i v a t i v e s , such a s the a c e t a t e , b e n z o a t e , e t c . , w i t h b o i l i n g points o r o t h e r p h y s i c a l p r o p e r t i e s t h a t w i l l pzrmit e a s y s e p & r tt i o n i t w i l l be d i f f i c u l t t o dravu conclusions f r o m the r e s u l t s of t h e oromina t i o n . I cannot suggest ariy m o d i f i c a t i o n i n the a p r a r - atus. I t worked wel.1 f o r th2 purpose d e s i r e d . i t s c o n s t r u c t i o n a r e f'ou-ncl i n t l i i s . p a p s r . &tails of The p r e p a r a t i o n of brom-para-eresol i n water s o l u t i o n . C e s c r i p t i o n of a rwn, an? method used f o r e x t r s c t i o n . +f-;,L - ++St F i f t y grams of p z r a - c r e s o l were d i s s o l v e d 4 l i t e r s of water i n t h e 1 2 l i t e r Pyrex f l a s k . ifi Twenty- t h r e e c c ' s of b r a n i n e , d i s s o l v e d I n 6 l i t e r s of water, was slowly introduced through t h e s e p a r a t o r y funnel; the complete i n t r o d u c t i o n timed t o about one and one-half hows . The s o l u t i o n of p a r a - c r e s o l was v i a o r o u s l y s t i r r z d t h r u o u t t h e r e a c t i o n t o m i n i ~ i z ethe Tormatiori of d i - and A tri-brom c o ~ ~ o b n ddus s t o a l o c a l excess of brwmine. f l o c c u l e n t p r e c i p i t z t e of brom-para-cresol forEed i n t h e water s o l u t i o n . i s immediately Vhen a l l t h e bromine i s i n t r o - duced i n t o the r e a c t i o n f l a s k and the r e a c t i o n i s c o m p l e t e d , s a l t i s tidced t o excess t o lower the s o l ~ b i l i t yof e t h e r i n the s o l u t i o n . A f t e r the a d d i t i o n of the s a l t one l i t e r oi' e t h e r i s ar?ded, e ~ ~t h ed mixture s t i r r e d . of e t h e r i s added, about two of A t o t a l of t'nree l i t e r s the^ i n the e x t r a c t i o n f l a s k , and th* o t h e r i n t h e 3 l i t e r P y r e x r e c e i v i n g f l a s k . Enough i c e cold water i s added t h r o u ~ hthe c o i l condenser t r a p t o b r i n g t h s l a y e r of t h e s o l u t i o n i n t h e e x t r a c t i o n f l a s k up t o the overflow i n t o t h e r e c s i v i n g f l a s k . The s t i r s e r s must be a d j u s t e d s o t h a t when they are running, about t h r e e i n c h e s of e t h e r layer remains i n t h e upper p a r t of t h e e x t r a c t i o n f l a s k . THIS I S IMPORTANT; OTHERSISE WATER WILL BE CARRIED OVER I N T O THI? RRECEIVING Fage S i x The h o t water h e a t e r must be a d j u s t e d f o r e l e c t r i c i t y and water flow a t a , temperature of' ~ O - E J ~ ~ C . The cold water con3ensers must have a good flow of water, f o r t h e e t h e r vapor comes over a t a r a p i d r a t e , and must be condensed. With t h e h o t water a t t h e proper tempsrature, about 20 c c ' s of e t h e r should be d i s t i l l e d over por minuts. The s o l u t i o n i n the e x t r a c t i o n f l a s k g r a d u a l l y changes c o l o r due t o t h e i n t r o d u c t i o n of f r e s h e t h s r , a n d t h e c o l l e c t i o n of t h e brom-compounds i n the r 3 c s i v i n g f l a s k . The s x t r a c t i o n should continue f o r at least 2 4 hours. A t %he end of t h ~ extraction the s t i r r e r s a r e stopped, and cold water i s introduced i n t o t h e e x t r a c t i o n f l a s k (slowly!) u n t i l all the e t h s r l a y e r hzs flowed i n t o the receiving f l a s k . The stop-cock of t h e s e p a r a t o r y funnel i s then c l o s e d , and t h e "Tn connection from the weter cond e n s e r to t'ne sepwatory funnel can ba connr3cteP c?i;-sctly t o a 3 l i t e r boZXle f o r t h e r e c s p t i c ; ~3f t h e excess e t h e r now p r e s e n t i n the rnceivina flask. 'This e x c e s s e t h e r i s b o i l 4 off until o n l y 400-500 c c ' s a r e l ? f t i n t h e r 5 c s i v i n g flash. The brom-para-cresol cornpuncl.~a r e sol.uble i n this avount. The brom-para-cresol compounds i n eth,*r a r e cooled, and d r i e d f o r s e v e r a l weehz over a n h y d r o u s s o d i m s u l f a ts . To s t o p t h e e x t r a c t i o n a t any time a l i t h a t i s n e c e s s a r y i s t o s t o p t h e motor, r. 13 s t o p t h e wster h e a t e r , which a u t o m t i c a l l j surrounds t h e e t h e r i n t h e r e c e i v i n g f l a s k with cold water and the v~ho1.eprocess c ? n ? s s . J Vhesl the p a r a - c r e s o l was bronlinated i n 1 2 Eu'. hydrochloric a c l d t h e f cllowing m o d i f i c a t i o n s of the proceedure i n water s o l u t i o n ~ 2 necessary: ~ 4 E t h e r i s s o l u b l e i n concentrated hyclrochloric an? a c i d s o l u t i o n , due t o t h e formation of s a l t ~orr~pounds, t h e r e r o r e the a c i d ha6 t o be n e u t r a l i z e d , o r nea-l-y s o , bef0i.e t h e e t h e r was indlroduced. NaHC05 was used, and was s l o ~ i l y(CAUTION!) added t o t h e a c i d i m ~ e d i a t e l ya f t e r t h e cresol K;S mas used. brominatsd. A s l u d e e o f b i c a r b o n a t e a ~ dwater Considerable d i f f ul t y was enountsred t o p r e v s n t foaming, a n d consequent l o s s of sons of t h e products or t h e a* reaction. B e c a u ~ eof the f o m z t l - o n of PTaCl b y tke r e a c t i o n of t h e bi-carbonate an6 t h e a c i d , no a d d i t i o n a l s a l t was needed. The s a l t c r y s t a l s formed i n a very f i n e s t a t e t h r u o u t t h e s o l u t i o n , allnost l i k s a f i n e p r e c i p i t r t e , b u t upon s t e n d i n g they w r e transformed i n t o l z r g e c r y s t a l s . Page E i g h t The vacuum d i s t i l l a t i o n a p p z r a t u s :firas a r e g u l a r s e t - , ~ p , c o n s i s t i n g of Claysen f l a s k , condznser, r e c e i v i n g flask with f i v e c o n t a i n e r s , which psrmi t t e d f r a c t i o n a t i o n without stopping d i s t i l l a t i o n , d r y i n g tube c o n t a i n i n g C a C 1 2 , mercury manometer, water t r a p , three-way stop-cock, end A vacuum as low as 16 mm ivns o b t a i n e d . water vacuum pump. A c e r e s i r i b a t h was used t o r a i s s t h e terLlpsrature up t o 150°C, and f o r h i g h e r temperatures t h e d i r e c t Eunsen flame was used. A small c o i l of g l a s s t u b i n g was ussC? with the Claysen flask,"and acted as a f r a c t i o n a t 5 n g column. Some of t h e minor p o i n t s of the problem vrhlch d e s e r v e mention are: The e t h e r had a bsd e f f e c t on a l l rubber p a r t s ; t h e a l t e r n a t e s w e l l i n g and d r y i n g caused t h e rv.3Ser t o crack badly, and i t was soon rendersd w o r t h l e s s . was found No r e m e d y . The e t h e r recovery was only about 50 p e r c e n t , due no doubt t o t h e low temperature a t which i t b o i l s , a n d the cousequvont dir'i'ul t y of w o r k i n g ad. t 3 i t a t room tsnjperature . The sodium s u l f a t e used f o p d r y i n g nus st be finely divided. About 200 grams was used t o d r y 500 c c of' t h e e t h e r s o l u t i o n c ? t h e ' c r o m cor~~pounds. Ths s x t r a c t i o n appara t u s was simple t o o p e r a t e , and should be of value i n a n y p r o c e s s i s d e s i r e d without much hand l a b o r . here long e t t r a c t i o n RESULT OF TIME RUN FOR BR- WHEN ORTHOBROM-PHENOL WAS KFPT IN THE FPZSFXCE OF RATER. 3 - 3: Bhen work on t h e bromination of phenol and cresol i n water s o l u t i o n was f i r s t proposed i t was thought p o s s i b l e t o remove t h e water t h a t was used f o r the s o l v e n t by b o i l i n g , o r a t l e a s t b y r a i s i n g the t o t h e p o i n t where i t would stezm. t o work i n vacuo. w2 t e r I t was even proposec? A s i s shown i n t h e ctetailed v a l u e a of' the r e s u l t s obkained t h i s mathod of removing t h e excsss wzter was n o t a s u c c e s s . I t was thought that the continued pressnce o f water o r water vapor a t room temperature would s e r i o u s l y affect t h e s t a b i l i t y of t h e brom-phenol molecule, c a u s i n g part of t h e p ~ o d u c tt o break down, g i v i n g R r - . To provs whether t h e r e was t h i s b r e a k i n g up of t h s molecule, two solutions of ortho-brom-pknol i n water, one .IN acid arid t h e other- n e u t r z l , were t e s t e d f o r s e v e r a l d a y s f o r the presence of W- by t h e s t z n d a r e v o l u m e t r i c a n a l y s i s of AgN03 and WH4SCW, using f s r r i c alun, a s ar, iyldi-cator. Aftel> s e v e r s 1 d a y ' s t e s t s , i t was conclude? t h a t t h e r e rvss no i n r J i c a t i o n of the decomposition of' t h e brom-phenol compound. It was found, though, that lnfhora a w a t e r s o l u t f 0i.l of o r t k o - b r o ~ p h e n o l contained a s l i t t l e a s 0.05 mama of Na2C03 t o every .163 grams of brom-pksnol and was heated t o 60°C f o r 1-$h o u r s , enough AgBr was p r s c i p i t ~ t a don t h ? a d d i t i o n of A g B 0 3 t o be visible. Page Ten DETAILED DATA ON BROM-PHENOL and BROM-PARACRESOL MADE I N PATER SOLUTION and i n 12 N . HYDROCHLORIC A C I C SOLUTION. A 10 grams phenol 300 c c water 3 c c bromine 500 c c water To 220C , time: 1 hour Solvent: C C 1 4 - n o t s e p a r a t e d . Tri-brom Yield very imperfect Tried b o i l i n g phenol r e - d i s s o l v e d i n water. e x c e s s m t e r o f T c ~ ed x t r a c t i n g wi t h C C 1 - b u t l o s t much product i n e s c a p i n g steam. N O * a pracLica1 method of removing water. - B To 2Z°C 50 grams phenol 1500 c c water 28 cc brogiine time: 1 hour solvent: CC14 2500 c c water Gross y i e l d o f o , p, d i - , tri-brom-phenol was 34 grams. Not a good s e p w a t i o n of organic prod u c t s from t h e w a t w s o l u t i o n . Tri*brom-phenol ( ? ) forrried brown o i l mass i n water. - C 50 grams phenol 2500 c c water To 23OC time: 1 hour solvent: G C 1 4 28 c c bromine 5000 c c water L e s r s o l i e p r 3 c i p i t 2 t e d11e t o l a r g e r . amount of w a t e r p r e e e n t . I t was found t h a t C C l q was n o t a s u i t a b l e s o l v e n t , and a f t e r t h i s experiment e t h e r was substituted. - D To 2 2 O C 50 grams phenol 2500 cc water 28 c c bromine 5000 cc water time: 1 hour solvent: ztker Continuous e x t r a c t i o n a p p a r a t u s (1922-23 m o d e l ) usec3.. W t r a , c t i o n time approximately one Bay ( 2 4 hours) S a l t added t o water s o l u t i o n b e f o r e e t h e r was added t o lower s o l u b i l i t y of e t h e r i n water. . - E D u p l i c a t e of D. D and E were mixed, and t h e n d i s t i l l e d i n vacuo, and products c a t a l o g e d under Key Number I. Faae E l e v e n D i s t i l l a t i o n Record D and E -A - 86.0' 84.5' 2 1 nun 65 grams 71% e x t r a c t i o n To 20°C 50 grams phenol 2500 c c water 28 cc bromine 5000 cc water time: 1 hour s o l v e n t : ether S u c c e s s f u l r u n with newly designed a p p a r a t u s (192324). a D i s t i l l a t i o n Record - 82' A - ?go D - 124O up 25 grams 16 mrn - 4 " recovered from flask 53% e x t r a c t i o n To 2G OC 50 grams p a r a - c r e s o l 4000 cc water 23 cc bromine 6000 cc water time: 1% hours solvent: ether Successful r u n of 1922-23. - D i s t i l l a t i o n Record - 101.5O -A 1Ol0 B - 10 4 O -*119.4 120.5O 49% e x t r a c t i o n 18 rnm 42 grams 28 mrn 6 " Page Tv?relve 50 grams p a r a - c r e s o l 4000 cc 1 2 N HC1, corn. 23 cc bromine 3000 c c 1 2 M H C l , corn. To 20°C time: 15 h o u r s solvent: ether e x t r a c t i o n time: 24 hours 1923-24 improved a p p a r a t u s a s shown in d r a w i n g . D i s t i l l a t i o n Record - 105O A - 104O D - " 140° resieue 20 m m 16 decomposition was r a p i d a t t h i s temperature. 20 mm 51 grams - 85% e x t r a c t i o n . a - Duplicate o f V D i s t i l l a t i o n Record 0 19 mrn 3 grams 20 mrr 46 " 140° r e s i d u e same decomposition n o t i c e d a t t h i s To. 97 $ e x t r a c t i o n . 50 grams p a r a - c r e s o l 4000 c c water 2 3 cc b r ~ m i n e 6000 c c water To 2Q°C time: 1s hours solvent: ether e x t r a c t i o n t i r e : 2 4 hours * i n d i c a t e s To where bulk of d i s t i l l a t e cams over. Page T'nir teen BII, continued Distillation record - 102.50 - 19-20 mn: 38 grams A - 1010 %10 40 -C 152O D - residue a 157O 20 rnm 16 " 13 " 70 $ extraction VIII Duplicate of VII - ~ i s t i l l a $ i o n record A - 1Ol0 -*lo 4 O 2 0 - 2 1 mm 50 grams 60 $ extraction IX Number VIII refractionated. Oistillation record 26-27 mm 8 grams a - 80° -87.5O B - 135O 1%' 6-7 CF 11 " gas, vapor, much bubbling i n flask; dscomposition ( ? ) . The peculiar results of this fractionation have not been explained. - . page F o u r t e e n Phenol d i s t i l l s a t 84OC, a t 20 mm. Para-brom-phenol d i s t i l l s a t 124.5O- 125O a t 20 mm. 2Brom-para-cresol (Pomeroy) d i s t i l l s a t 1? s o at 20 rpm. 2Brom-para-cresol, (Scudder) d i s t i l l s a t 136.5 a t 21 mm. 1 - 138.5O Para-cresol d i s t i l l s a t 9 9 O a t 19 mm. 3Erom-papa-cresol (Hough) d i s t i l l s a t 103 19-20 mm:: . Number X. 3 , 5 di-brom-para-cresol made i n C8, - 105.5O a t s o l u t i o n from U bromine and p a r a - c r e s o l . 50 grams c r e s o l 200 c c CS2 46 c c bromine 100 c c CS2 Df s t i l l a t i o n r e c o r d . TO 20°C time: 1 hour Coi.1 of' n i c i ~ ~ o r cwel . m l n miter c o n d e n s e r j a c k e t , P S ~ U ~ E7 Z , by r h e o s t a t below ( 3 1 , and which k e p t m t e ~a t 50°C. w t o r y f ~ m i d 1u s e d t o ir. t r o d i ~ c eand regu?.zte brolrine s o l u t i o n , a n d c l s o c o l l - e c t e d e t h ~ ai r~t s r ext r a c t i o n was f i n f s b s d . T a t e r conder-ser to candense e'Ll?er v a p o r s * mi-i.th ( 6 ) in series with c i t y water malns. Cor,r&eLed Do1 ble a c LLon stlr~err,oL v i s i b l a In f l askJ but pun S r O r rnoLor and s ~ s t e cL' k ~ d . 3- ~ 7 ~ ' I h. o r o u ~ hs t f r r l r , ~i ~s r y 2 e s 2 n -Lw ,, to b e a k ~g e t h e r s-t;.i5eal,a . ~ l dlaj51". Fape S i x t e e n 153 d r a w i n g o f ction flask s t i r r e r and o t h e r p a r t s attached t o cork. S t i r r e r is arranyed t o revolve i n opposite directions. P a g e Seventeen P h y s i c a l Constants -2 Brom-pera-cresol Phenol 3 , 5 di-brorn-para- cresol @ - 56O mp bp 55O 245O bp 136.5O mp bp bp 183O a t $60 mtr' 8 4 > a t 20 mm - 24G0 a t 760 mrn - 138.s0 a t 21 rnm 42,EJ