THE SYNTHESIS AND BROMINATION OF BETA BETA DIPHENYL GLUTARIC ACID BY WILLIAM ROBERT REICH THESIS FOR THE DEGREE OK BACHELOR OF SCIENCE IN CHEMISTRY COLLEGE OF LIBEHAL ARTS AND SCIENCES UNIVERSITY OF ILLINOIS 1922 . UNIVERSITY OF ILLINOIS p .192 lay THIS IS TO CERTIFY THAT THE THESIS PREPARED UNDER MY SUPERVISION BY ^ 1 1 1 X '31™ f>Y\, ENTITLED JC’S.-P.xsnajLa 3_p_ 1 £ ri~_ RL cTig CA-Tj-L'i.z'i _ IS APPROVED BY ME AS FULFILLING THIS PART OF THE REQUIREMENTS FOR THE DEGREE OF __JSach.sulo.r--- o£— Science. j_T 3 Qh e> j g 3 [* y Instructor in Charge Approved : ^C.AKA f* 0 Y 'SA. T*_3^_ HEAD OF DEPARTMENT OF The author wishes to acknowledge the helpful guidance and suggestions given by Dr. B.L. Souther in the pursuit of these investigations. Digitized by the Internet Archive in 2015 https://archive.org/details/synthesisbrominaOOreic TABLE OF CONTENTS Page Theoretical 1 Historical 4 Experimental 9 Summary 21 Bibliography 22 THEORETICAL The object of this work was the preparation of a cyclopropene in order to study its reactions. Very few substitut- ed cyclopropenes have been prepared. Feist 1 prepared methyl /C-COOH cyclopropene dicarboxylic acid, CH^ - CH'^ and Jones studied some of its reactions. Perkin and Thorpe-' 1 prepared ethyl dibromo- y 3 - dimethyl glutarate in the expectation that the elimination of two molecules of hydrogen bromide would give di- methyl cyclopropene dicarboxylic acid. However, they did not obtain any of the unsaturated acid and concluded that it was so active that it united with the alcohol present as soon as it was formed according to this equation C-COOH (OH,) 2 o'll > - C-COOH + C 0 H c OH = (CH,) 2 C( 2 5 * ^ CH- ^OCoHp c '"-COOH COOH Ingold and Thorpe 4 have performed the latest invest- igations upon cyclopropenes. They prepared cyclopropene-dicar- boxylic acid but from its reactions it could not be ascertained whether its formula was this ch ^q_pqok or " tills CH 2 v c COOH It was supposed that the two forms were in equilibrium with each other. If -diphenyl-glutar ic acid is brominated and then two molecules of hydrobromic acid are split out it will in all probability gi ,r e a substituted cyclopropene. / .CHBr-COOH . ... (C^Hc)p c' = 2H Br + (CgHc) 2 c -s p o CHBr-COOH 0 p c “ .C-COOH C-COOH . I ' ' - 2 - From this equation it is obvious that the only other possibility would be for a hydrogen atom to split from the phenyl group but this would be contrary to the ordinary reactions of that group. Accordingly the problem resolves itself into the preparation and bromination of y^.^-diphenyl glutaric acid. The first method that was tried was by the action of sodium malonic ester on benzophenone chloride? (C 6 H 5 ) 2 C 01 2 + 2Na [CHCCOOC^gj = (C 6 H 5 ) 2 < qh ^000^ /-COOE p ^ n "COOH - tG 6 h 5 j 2 ^COOH j COOC2H5 /CHgCOOH = (C^r) 2 C ^ CH2 C00H COOH Since this reaction gave a non-crystalline resin- ous mass which was a mixture of acids it was given up in favor of other methods. 5 Ethyl y£,/?-diphenyl-/9- hydroxy propionate was pre- pared by the following reactions: Br BrCHg-COOEt + Mg = Br JlgBr Mg( " + (C6 Hc) 2 c-0 = (c 6 hJ 2 C CH 2 C00Et ^ 3 /0 -MgBr (°6 H 5) 2 C ^CH 2 -C00Et + H0H = ^ C 6 H 5^2 Cv CH 2 -C00Et + Mg OH Br "CH 2 C00Et OH Bromine was substituted for the hydroxyl group by means of phosphorus tribromide but it was found that the ethyl - p > p- diphenyl- p - bromo-propionate thus formed was unstable since it gave off hydrobromic acid and formed ethyl - y^./^aiphenyl acrylate. This compound was therefore too unstable to work with. . i u; J&jlpi - 3 - Ethyl diphenyl acrylate was also prepared by the dehydration of ^^-diphenylyS' hydroxy propionic acid by means of acetic anhydride and then esterifying. Malonic ester reacted very smoothly with this compound in the presence of sodium ethylate and the complete absence of water, according to the following scheme. ^CQOEt yCOOEt v ^/° MN COOEt (CgH 5 ) 2 C = CH-COOEt + H 2 Cs C00Et - IC&h C n CH 2 “ COOEt Upon the saponification of this compound and sub- sequent heating it should lose carbon dioxide and form J3 , ^-di- phenyl glutaric acid. 'COOH .CH^COOH = (c^) P c; ‘CH 2 - COOH p> ,J3 -diphenyl glutaric acid can probably be brominated directly with bromine and phosphorus and by then re- moving two molecules of hydrobromic acid, the desired substituted cyclopropane can be obtained* pu^COOH .CH o C00H <*V 8 = ( ^ >2 C ^cooh + C ° 2 - 4 - HISTORICAL In order to obtain an idea of a method of prepara- tion and the properties of p, /3-diphenyl glutaric acid, the liter- ature was searched for compounds of similar structure, namely, /3 -substituted glutaric acids. The methods of preparation are given below and the properties and references are recorded later in tabular form. 1 I. Darbishire and Thorpe prepared p- methyl glutaric acid by the action of ethyl cyanacetate on the ethyl ester of p>- methyl acrylate. The ethyl- cx -cyano - p -methyl glu- tarate formed is hydrolizea by means of dilute sulfuric acid. The p>- methyl glutario acid is recrystallized from concentrated hydrochloric acid. II. Blaise and Zault prepared Jl substituted glu- taric acids by converting r substituted c* diketo pimelic R ^QTI PQQW acids " to corres P° nd - in S dioximes, reducing these to the dinitriles and finally hydrolizing the nitriles to acids. methyl, y3-ethyl and^^-hexyl glutaric acids were pre- pared in the same way. III. E. Knovenagel prepared p -methyl and ]3 -iso- propyl — glutaric acids by condensing acetaldehyde and isobutyl aldehyde respectively, with malonic ester in the presence of die- thylamine, and saponifying the resulting product. IV. j3 -acetoglutaric acid was prepared by heating ethyl^yS? -aceto-tricarballylate in the presence of hydrogen 1 References are given in table. * * . - ■ - 5 - chloride. Upon heating p -aceto glutaric acid it is converted into the keto-dilactone which can be reduced by hydroiodic acid in the presence of phosphorus to p -ethyl-glutaric acid. V. Micheal obtained p -phenyl glutaric acid upon reacting sodium malonic ester with ethyl cinnamate and subsequent- ly saponifying the product. VI. Avery and Bonton prepared benzal malonic ester by reacting benzaldehyde and malonic ester. This benzalraalonic ester was then reacted with sodium malonic ester and a good yield of /2> -phenyl glutaric acid was obtained upon the saponification and heating of this product. VII. JS , p -dimethyl glutaric acid was prepared by Perkin by saponifying and heating the product obtained from the reaction of pp -dimethyl acrylic ester and sodium malonic ester. VIII. If two molecules of cyanacetic ester and one molecule of acetone are allowed to react for one month in the presence of a few drops of diethylamine, a ten percent yield of dimethyl-methylene-dicyanacetic ester is obtained. This ester can be hydrolyzed to p,f 3 -dimethyl glutaric acid by means of di- lute sulfuric acid. IX. Awers obtained a 35 percent yield of p> > [3 - dimethyl glutaric acid by the reaction of potassium malonic ester on p, [2 -dimethyl acrylic ester. X. Kommpa prepared Jfi t J3 -dimethyl glutaric acid in a unique manner. He condensed mesityl oxide with sodium malon- ic ester and upon treating the product of this reaction with hot barium hydroxide solution he obtained dimethyl hydroresorcin. . . * . « . - 6 - This is oxidized almost quantitatively to -dimethyl glutaric by sodium hypobromite. XI. Thole and Thorpe prepared ^3- substituted glutar- ic acids by condensing various ketones with cyanacetaraide and sub- sequently hydrolyzing by means of sulfuric acid. The ketones used were ethyl methyl ketone, acetone and cyclohexanone. XII. Meerwein condensed benzaldehyde and malonic est- er in the presence of a small amount of sodium ethylate and upon saponification he obtained phenyl glutaric acid. p>- o-nitro phenyl glutaric acid was made in the same way using o-nitro ben- zaldehyde in place of benzaldehyde. It was also made by nitrating -phenyl glutaric acid. Following is a table of the properties of the above mentioned glutaric acids. The method of preparation is designated by the Roman numeral directly before each description. The follow- ing abbreviations are used: Et OH Me OH pet . sol. ethyl alcohol methyl alcohol petroleum ether soluble slightly soluble. si. sol. = - ■ . . - 7 - Forrnula M.P. M.P.cf Anhy- dride Meth- od Solubility Ref erenoe ch 2 -cooh CH^- 9 -H ^ CH 2 -C00H S 6 ° 06 0 S 6 ° S7° 46° 41° 47° I II III sol. Et OH Me OH hot H 2 0 si. sol. CH Cl^ Ether" benzene pet . eth. J.Chem. Soo . S7 , 1717 Ann. 21 g, 150 Bull.soc . chim.4 1, 75 Ber. 11, 25 S 5 ch 2 cooh G 2 H 5 -C-H CHgCOOH 73° 73° B.P. 15 S 0 (13 ram.) II IV sol. Et OH Me OH si. sol. Ether benzene CH Cl, pet-etnex Bull.soc .chim.4 1,75 Ann. 295,, 103 „ TT CHp-COOH CH -7 1 3CH-C-H ch 3 CH 2 "C00H 97° - III sol. pet. eth Et .OH C S P CH Cl^ si . sol . benzene ether Ber. 11, 25 S 5 CH C%-COOH ^CH-CHg-C-H ch 3 6 h 2 -cooh 4S° - III sol. ether Et OH benzene si. sol. pet . eth, C S P hot H 2 0 ^ Ber. 21, 25S5 ch 2 cooh C^-C-E ch 2 cooh 37° B.P.194 0 (12 mm. ) II sol. ale. eth. benzene si. sol. C.S 2 h 2 o Bull, soc . chim ^ 1, 75 ch 2 cooh g^Hc-Q-h J ch 2 cooh 137° 140° 142. 3 C l 6 S° > V VI XII sol. benzene Et .OH pet . eth si. sol. eth. hot H 2 0 CH Cl^ J.Prakt .C-hem. 2 25, 352 Am. Cham.J. 20, 511— Ann. IbO, 345 - s - Formula M.P. M.P. of An- il yclrieb Meth- ; oa Solubility Reference NO 2 .CH 2 -C 00 H A- C-H N ch 2 -gooh 205 ° - XII sol. pet.eth. benz ene e£ OH si. sol. eth. CH CI 3 Ann. 260, 3^5 CHp-GOOH 1 CH 3 - O—OH 3 ch 2 -cooh 101 ° 100 ° 101 ° 101 ° 101 ° 124° 124° 124° 124° VII VIII IX X XI sol. Et OH Me OH ether benzene pet . ether si. sol. hot HpO H Cl J .Chem. Soc . 6 £, 1457 Ber. H, 3530 Ber. 28, II 30 Ber. 22, 1421 J. Chem. Soc . 23., 429 GHp-COOH 1 c CgH^-C-CH^ D CH 2 “G00H S6° B.P. 1 S 5 0 XI sol. Et OH benzene si. sol hot H 2 0 H Cl J. Chem. Soc .99.429 0 CHp-COOH « 1 GH 3 -O-C-H ch 2 -cooh 48° - IV sol. Me OH Et OH si. sol. ether benzene CH Cl^ Ann. 295. 103 CHp-OBg CHd3 00H / " \ / CH C 'CH 2 -C% ' CH 2 C00H . 181° L 73° XI sol. Et OH Me OH benz ene ether si. sol. hot HpO c^s 2 J . Chem. Soc .99 , 429 - 9 - EXPERIMENTAL Preparation of Benzophenone Chloride by Friedel and Crafts Reaction. 130 c.c. of carbon tetrachloride were mixed with 25 gm. anhydrous aluminum chloride in a 500 c.c. flask with a reflux condenser and hydrochloric acid trap attached. 100 gm. of dry benzene was then added slowly by means of a separatory funnel and the mixture was allowed to react for four hours. The mixture was then poured into cold water and the oily layer quickly separated to prevent the hydrolosis of the benzophenone chloride to benzo- phenone. The excess of carbon tetrachloride was removed on the steam bath and the remainder of the solution was then distilled under 50 m.m. pressure, the fraction from 204°-206° being collect- ed. The yield was 13 gm. or 4 percent of the theoretical yield. 6 Preparation of Benzophenone Chloride from Benzophenone. 100 gm. of benzophenone and 165 gm. of phosphorus pentachloride were heated at 160°~1S0°G for four hours in a flask with a reflux condenser attached. The mixture was then distilled under 50 m.m. pressure, the fraction 200°-210° being collected. This fraction was redistilled under the same pressure and the pure benzophenone chloride was collected between 204°-206°c. The yield is 70 gm. or 60 percent of the theoretical. The benzophenone chloride prepared in this manner is a clear liquid with a bluish fluorescence. 7 Reaction of Benzophenone Chloride and Malonic Ester. 13.6 gm. of pure malonic ester and l.S gm. of sodium were allowed to react to form sodium malonic ester in $0 c.c. of > . . . - . * * * 1 /. ... ■ • • - 10 - anhydrous benzene. 10 gm. of benzophenone chloride were then adaed and the mixture was heated on the steam bath for 15 hours. The solution was then washed several times with water and the benzene was evaporated. A yellow viscous liquid resulted. This liquid was saponified by heating at 100° for 12 hours with 13 gms . KOH in 40 c.c. ethyl alcohol. This alcoholic solution was then poured in- to 300 c.c. cold water and the water was extracted with ether to remove any unchanged ester. The clear yellow water solution was acidified with hydrochloric acid and a cloudiness resulted. The acid was extraced with ether and the ether solution was washed with 25 percent sodium carbonate solution and then with water. The solution was dried over anhydrous sodium sulfate and the ether was evaporated by means of a current of dry air. A resinous fluid was obtained which would not crystallize from ethyl alcohol, ether or benzene. It was slightly soluble in hot water. In order to analyze this acid it was exactly neutra- lized with dilute ammonium hydroxide and the silver salt was then precipitated by adding a slight excess of silver nitrate. This precipitate was washed with alcohol and ether and dried in a vacuum dessicator. A weighed amount of the silver salt was then placed in a crucible and ignited to pure metallic silver. Analysis I weight of silver salt I . 170 S II . 076 S weight of silver .06g4 .0311 percent of silver 40.0 fo 40.4 $ Following is given a table of the salts which might have been formed by the above reactions: - 11 w /C00Ag (CgHjr ) 2 C ( ' C00AS b 5 " WCOOAg "COOAg Mol. Wt. soo Percent of s i lv er 54.0$ yCHLCOOAg (c 6 H R ) c d D 2 * CH 2 C00Ag 49 g 43.4 $ /COOAg (c 6 h 5 ) c = C s 0 3 d COOAg 4S2 44 .S$ 4. ^°6 H 5^2 C = CH-COOAg 331 32.4$ From the above data it is obvious that a mixture of two or more of the above acids were obtained by the reaction be- tween benzophenone chloride and malonic ester. g Preparation of Mono-brom Acetic Acid. 250 gm. glacial acetic acid and 13 gm. of sulfur were mixed in a liter flask with a reflux condenser and bromine trap attached. 66 J gm. of bromine was then added slowly by means of a separatory funnel. The mixture was allowed to react on a steam bath until the bromine disappears. It was then distilled under 30 mm. presure, produced by a water pump, and the fraction between 125 °- 135 ° was collected. This was further purified by distilling under atmospheric pressure, the pure bromacetic acid coming over at 207°-209°C. The yield is 59 percent of the theory. A 70 percent yield is obtained by the following meth- od. 300 gm. glacial acetic acid, S 50 gm* bromine and 20 c.c. acetic anhydride were mixed in a liter flask with a reflux condens- - 12 er and hydrobromic acid trap attached. This mixture ms warmed to 50° C and then allowed to react slowly for several days or until no more bromine was present. It was then distilled in the same way as before. This method has the advantage over the other meth- od because no troublesome sulfur by-products are formed as in the first method. Preparation of Ethyl-Brom-acetate. 100 gm. of bromacetic acid and Sp c.c. of absolute ethyl alcohol were mixed and saturated with hydrochloric acid gas. After standing over night the mixture was again saturated and al- lowed to stand for six hours. It was then poured into &00 c.c. ice water, and the ester was extracted with ether. After evaporat- ing the ether the residue was distilled and the following fractions were obtained. 150 0 - 155 0 c 16 gm. 155°- 160 0 c 3 ^ gm. 160 0 - 165° 0 31 gm* 165 0 - 17 o° c 20 gm. Since the ester prepared in this manner had no de- finite boiling point, it may be concluded that the chlorine from the hydrogen chloride replaced some of the bromine in the ester, thereby giving a mixture of chloracetic and bromacetic ester. 9 Demole has found that an equilibrium mixture of monobrom and mono- chlor acetic acids exists when hydrobromic acid is added to mono- chlor acetic acid. Accordingly the following method was used to obtain pure ethyl bromoacetate. 100 c.c. ethyl alcohol, 2^0 gm. brom- - - 13 - acetic acid and 30 gm. concentrated sulfuric acid were mixed to- gether and allowed to stand for six hours. The mixture was then poured into £00 c.c. of cold water and the ester layer was separat- ed. The water was extracted with ether to remove the remainder of the ester. After evaporating the ether the residue was distilled, the fraction 159°- l60° being collected. A ninety percent yield was obtained. Preparation of E^hyl y&/3 -diphenyl- -hydroxy propionate. 3 gm. of zinc which had been purified by boiling with dilute potassium hydroxide and then with dilute hydrochloric acid and finally washed with alcohol and ether, were added to a solution of IS. 2 gm. of . benzophenone and 20 c.c. of bromacetic ester in 90 c.c. of dry benzene. The mixture was refluxed for three hours but the reaction did not take place as recorded by Rupe and Busolt. 10 The same amounts of benzophenone and bromacetic ester were then dissolved in benzene, which was dried over phosphorus pentoxide, and the solution was refluxed with £ gm. of a zinc cop- per couple for twenty four hours. The solution was then poured into cold dilute sulfuric acid and after mixing thoroughly the re- action products were extracted from this acid solution with ether. The thick brown liquid which was left upon evaporating the ether was dissolved in alcohol and after standing for several hours a small yield of ethyl- -phenyl- [3 - hy do rxy-hydrocinnamat e crystall- ized out. Upon further crystallization benzophenone wns obtained* The zinc copper couple 11 which was used was made by covering some pure granulated zinc with a two percent solution of copper sulfate and allowing to remain until the solution was decolorized. This * . * ■ • • . . -14- was repeated and the couple was then washed with alcohol and ether and dried. Since the yield was so small by the above method the following modification was tried which gave very good results. 10.4- gm. magnesium, 55*6 gm. benzophencne and 60 gm. of ethyl bromacetate were mixed with J>00 c.c. of absolute ethyl ether in a 500 c.c. flask with a long reflux condenser attached. Upon warming to about 25° C a vigorous reaction soon begam which was cooled from time to time in order to keep it under control. Af- ter the reaction had subsided the mixture was allowed to remain ov- er night and was then poured into cold dilute sulfuric acid to hy- drolyze the magnesium compound which was formed. After complete hydrolysis the -phenyl- -hydroxy- hydro cinnamic ester was extracted from the acid solution with ether, the ether was evapora- ted and the ester was purified by crystallization from ethyl alco- hol. It separated as fine white needles which melted sharply at 34° C. The yield was S5 percent of the theory. Bromination of ethyl -diphenyl - ^ -hydroxy-propionate. 5 gm. of the ester were dissolved in dry benzene and 5 gm. of phosphorus tribrornide was then added slowly. The mixture was refluxed gently for an hour, hydrobromic acid being given off. After washing the benzene solution with dilute sodium carbonate the benzene was evaporated and a yellow viscous liquid remained which could not be crystallized from alcohol or ether and which gave no Beilstein test for halogen. The absence of bromine was probably due to the splitting out of hydrogen bromide to form the unsaturated compound ethyl- B.B -diphenyl-acrylate. - 15 - The same reaction was repeated using anhydrous ether as a solvent instead of benzene. Aout one gram of a crystalline substance melting at l6^°C was obtained which was probably di- phenyl acrylic acid. Also an amber colored liquid was obtained upon evaporating the ether which gave a positive Beilstein halogen test. This compound which was probably -diphenyl- ft - brom propionic ester gives off hydrogen bromide upon gentle warming. The Action of Sodium Malonic ester on Ethyl -diphenyl' 1 3 -brom-propionate. The ester made by the preceding reaction was dissolved in 30 c.c. of absolute ether and to this was added some sodium malonic ester solution which was made by disolving .33 gm. of sod- ium in a solution of 2.5 c.c. of malonic ester in 20 c.c. of ab- solute ether. The materials were allowed to remain a room tempera- ture for several days, a white precipitate separating out in the meantime. It was then poured into 100 c.c. of cold water and the ether layer was separated. The water was extracted with ether to remove the remainder of the reaction products. Upon evaporating the ether a light brown liquid was obtained which would not cry- stallize from alcohol, ether or benzene. Since thie liquid was an ester it was saponified with a slight excess of alcoholic po- tassium hydroxide solution without heating. After reacting for twenty four hours, the solution was acidified with hydrochloric acid and the white precipitate was filtered. The precipitate was dissolved in hot absolute alcohol and upon cooling beautiful white plates separate, which have a melting point of lol°- l62°c. This acid might have been any one of the three listed below: - ■ . ■ - 16 - Formula Molecular Neutral Weight Equivalent (C6H 5 ) 2 C = CH COOH 224 224 CHoCOOH (c 6 h 5 ) 2 c £ CH 2 C00H 284 142 COOH (c 6 h 5 ) 2 c CH COOH 446 148 CH 2 COOH Since the neutral equivalents of the above acids di- ffer considerably, that of the acid obtained was determined* Results I. .099^ gni. of acid was neutralized by 4.6 c.c. of .1006 N. sodium hydroxide solution giving a neutral equivalent of 217 • II. *1835 of acid was neutralized by 8*5 c.c. of .1006 N sodium hydroxide solution giving a neutral equivalent of 219 • These results identify the acid as being y#/foiphenyl acrylic acid which was formed merely by the ethyl'/3,y0 -diphenyl - p - -brom-propionate splitting out hydrobromic acid this reaction being hastened by the presence of alkaline sodium malonic ester* Preparation of p, p> -dipheny 1-Acrylic Acid. 40 gm. of p> - diphenyl- JS> -hydroxy propionic ester was saponified by heating with one and one half times the theoreti- cal amount of 25 percent alcoholic potassium hydroxide for twenty four hours. It was then diluted with water and acidified with hy- drochloric acid after removing any unchanged ester with ether. 30 gm. of acid was obtained upon filtering the acidified solution. This acid is dissolved in 20. 3 gm* of acetic anhydride and heated to 150°C for three hours in the presence of 2 gm. of - 17 - anhydrous sodium acetate. It is then poured into cold water where the acid was precipitated and the acetic anhydride was decomposed* The acid was filtered, redissolved in dilute sodium carbonate and this solution was boiled with bone black to remove the coloring matter. Upon removing the boneblack and reacidifying this solution the acid was precipitated as a white powder which melted at l60°- 162° C. Esterification of .p -diphenyl-acrylic acid. 7 gm. of the acid were dissolved in 25 c.c. of abso- lute ethyl alcohol and S c.c. of concentrated sulfuric acid was add- ed and the whole refluxed for three hours. The solution was poured in 200 c.c. cold water and the ester was extracted with ether and the ether was washed with dilute sodium carbonate. The residue left after the evaporation of the ether would not crystallize from alco- hol, benzene or petroleum ether. Because a crystalline product was not obtained by the preceding method this method was tried. 7 gm- of the acid were dissolved in dilute ammonia, care was taken to use no excess of ammonia. An excess of silver nitrate was then added and a white heavy precipitate was formed. This precipitate was washed with al- cohol and ether and then dried. It was placed in a flask with 90 c.c. of absolute ether and 14 c.c. of ethyl iodide was then added* Upon refluxing this mixture for two hours a yellow precipitate of silver iodide separated. This precipitate was filtered off and the ether was evaporated. The ester was then recrystallized from abso- lute alcohol. The crystals separated as white plates with a melt- ing point of 114° C. . - 18 - Analysis of this Ester. I II Weight of sample .1451 gm. .1901 gm. Weight of carbon dioxide .4310 gm. .5617 gm. Percent of carbon gi.i $ SO. 69 io Weight of water .0821 gm. .1094 gm. Percent of hydrogen 6 . 34 $ 6.44 # Calculated Composition Carbon so. 9 $ Hydrogen 6.4# Oxygen 12-7* A Method for the Preparation of Pure Absolute Alcohol. 4-0 c.c. of alcohol which had been dried over lime was poured over 10 gm. of magnesium. A small piece of sodium was added to start the reaction between the alcohol and magnesium to form magnesium ethylate. 4-50 c.c. of dry alcohol was then added to this magnesium ethylate solution and the whole was refluxed for two hours. It was then distilled without coming into contact with the air. Magnesium ethylate removes the last traces of water from alcohol according to this equation ( c 2 h 5 °) 0 Mg + 2H0H = 2C 2 H 5 0H + Mg(0H ) 2 Action of Malonic Ester on Ethyl- -diphenyl-acrylate. 6 gm. of ethyl- p, y3 -diphenyl acrylate and 4.5 gm. of malonic ester were dissolved in 70 c.c. of absolute alcohol which was prepared by the preceding method. .4 gm. of sodium dissolved in 8 c.c. of absolute alcohol was then added and the mixture was re- * * - * . • . . - 19 - fluxed on the steam bath for twenty four hours and then allowed to remain at room temperature for seven days. At the end of thi3 time it was poured into 200 c.c. of very dilute hydrochloric acid and a white solid separated. This filtered off and the remainder of the ester was removed from the acid solution by extracting with ether. The white precipitate was then dissolved in ether and washed first witha dilute sodium carbonate solution and then with water several times. The ether was then evaporated and the ester was crystalliz- ed from ethyl alcohol. 4- gm. of white leaf like crystals were ob- tained which melted at 15&° C, The compound which was obtained is probably represented by this formula ( c 6 k 5 ) 2 pTjxCOOCpHc vn 'C00C 2 Hg ch 2 cooc 2 h 5 Analysis of this Compound I II Weight of sample ♦3*317 .1376 Weight of carbon dioxide .973^ .3511 Equivalent of carbon .2656 .9577 Percent of carbon 69.6/0 69.6/0 Weight of water .2211 .0632 Equivalent of hydrogen .02476 .OO9S36 Percent of hydrogen 6.7$ 6.5/* Calculated Results Carbon Hydrogen Oxygen 69 .9 /o 6 . 2 % 23 • yfo 20 - Dehydration of Ethyl -diphenyl- -hydroxy-propionate. 5 gm. of -diphenyl- p -hydroxy-propionic ester were heated with S c.c. of acetic anhydride on an oil bath at 150° C. for four hours. At the end of this time it was poured into cold water, which decomposed the acetic anhydride. The white precipit- ate is filtered off and crystallized from hot absolute alcohol. It is found to be identical with the ester made by the preceding method. ♦ . * . 21 - SUMARY c h lor idfc. 1. It was found that benzophenone/\does not react smooth ly with sodium malcnic ester. 2. A new method was devised for the preparation of mono brom-acetic acid using acetic anhydride as a catalyst. This meth- od gave a clean reaction and a good yield. 3» Ethyl mono-bromo-acetate was made in good yield from this acid using sulfuric acid as a catalyst. Hydrogen chloride gives a mixture of esters. 4 -. Ethyl- prfS -diphenyl-/^ - hydroxy-propionate could not be prepared by means of the Reformatsky reaction from mono- brom-acetic ester and benzophenone as given in the literature. However, when magnesium was substituted for zinc the reaction went smoothly. 5 . Ethyl- -diphenyl - -bromo-propionate was found to be unstable, breaking down into ethyl-y?<^ -diphenyl acry- late and hydrogen bromide. 6. Malonic ester reacted with ethyl- fb , -diphenyl acrylate in fair yield to form the tri-ethyl ester of ( -di- l phenyl- - carboxy) ethyl malonic acid. - . - . ■ * * 22 BIBLIOGRAPHY 1. Ber. 26, 750 ( 1 & 93 ) 2. J. Chem. Soc. S7 . 1062 (1905) 3* J. Chem. Soc. 79 , 732 (1901) 4. J. Chem. Soc. 119 > 2001 (1921) 5 . Ber. 40, 453^ (190?) 6 . Ber. 2, 90S (IS 72 ) 7. Ber. 12, 1433 (1*99) S. Bull. Soc. Chim 3 I, 365 (IS 92 9. Ber. 2, 56 I (IS 76 ) 10. Ber. 40, 453S (1907) 11. Organic Chemistry, Perkin and Kipping, page 56 (1917) N.B. The references for the compounds mentioned in the historical section are given in the table at the end of that di- vision.