PREPARATION OF MONOMERIC ALKYL

Patented Apr. 19, 1949 UNITED 2,467,926 S;TA.TE.;S‘j PATENT OFFICE). 2,467,926 PREPARATION OF MONOMERIC ALKYL ALPI-IA- CYANO —ACRYLATES A1an.E. Ardis, Akron, Ohio, assignor to The B. F. Goodrich Company, New York, N. .Y., a corpo- ration of New York No Drawing. Application March 1, 1947,‘ Serial‘No. 731,863‘ 9 Claims. I This invention relates to alkyl esters of alpha- cyano acrylic acid and to a method of preparing them. Alkyl esters ;of alpha-cyano acrylic acid h9«Ve': heretofore -been ob»tained»in=the polymeric form by pyrolysis of-the cyanhydrinracetates of’ acetyl fattyiacidi esters. It has now been found that alkyl: esters of. alphacyanoacrylic acid may be obtained :by reacting an I alkyl -cyanoeacetate first with-an.a1kali'meta1.a1coho1ate and thenwwith. a compound of’ the general structure: R——O——CH2—X in which Rt‘ is an organic radical having. its..con-, nectingvalence on a carbon.atom.and.contain- ing.no reactive hydrogen atoms: (1. e.‘, havingall its hydrogen attached-. to carbon),.and-X: iS"‘«‘al1‘ halogen- atom. . Compounds illustrative » of. the. above general structure include the halo-methyl esters- of -mono- carboxylic acids (wherein R is an- acyl group): such. as chloro—methy-1- acetate, chloro-methyl . propi-onate, bromo-methyl acetate, chloro-methyl‘ benzoate, chloro-methyl chloroacetate, and other halo-Vmethylsesters of substituted orfunsubstituted ‘ aliphatic or cyclic monocarboxgylic acids; the halo-methylethers (Wherein.R, is ahydrocarbon» radical) such as chloro-methyl ether, chloro-~ methyl ethyl ether; chloro-methyl propyl ether, chloro-methyl triphenylmethyl ether andvothers,» as well as- any other compoundof the above gen‘- eral_ structure in-which Ruhas vario.us inertsube» stituent. groups such as halogen atoms, ether groups» and hydrocarbon groups.’ Preferably R is an -:alkyl; ar»y1’or. acyl radical containing from 1 tov»8 carbon-atoms-... According. tothe present invention an alkyl cyanoacetate -is reacted firstwith analkali metal. a1co.holate"and; then with; a; compound of the,- above structure, the reaction proceeding asuin-» dicatedin .the.. following equations: (1) H I A‘1k'—‘—0—-(!'T‘—(EH + M'—O——A]k ‘-——> O ' CN H I Alk——-0—C—C——M + Alk—OH.. I I o CN“ «10 , 15 20 NJ in 30 35 40 45 50 (Cl. 260—465.4) 2. (2) Fl! ~ AIk——0'—(|'|)—-(|J—M'+ X—CH2—OR ——-) ' 0 ON‘ H Alk-—O—?—(]2'—O‘EI7—‘-OR‘+ MK??? 6. in (3) H. A1k+O—.C——-+‘—.CH20’R ' u —-> to cN CH2=Cé——C—0Alk‘=+. »R—“.‘—OH‘;r. éN m'a'i-n -fraction *dis£ti1:ling "over -at -150 to 17'il°- ‘was. ~colleet.ed ‘a receiver immersed in liquid nitrogen. The boiling rpoint ~'ran=ge~'of 4:50 to '1!70.r° C. is not a true boiling point because a higher temperature. is: necessary to vdepolymerize the ester. The resulting monomeric. 'eth.yl~‘a~l.°pha- cyano acrylate polymerized easily when warmed to .50?’ ‘C. ‘or higher. The monomeric ethyl alpha-cyano =ac‘r;yla;te prepared in =Exampl'e= i had a ‘freezing point or —20 to 4-25“ G. -and '-upon "analysis was found to contain 11.21% nitrogen, 57.40% carbon, and 5.64% hydrogen ‘(theoretical for ethyl alpha- cyano acrylate is 11.20% nitrogen, 57.59% car- bon and 5.64% 5h.y'd»roge‘n=)-. "The hard polymer prepared frorn. the monomer --had a softening point or 1iob'c., a'm’e‘1ting p‘o"int.oIf .150 to 160° C. and was soluble in acetone but insoluble in alco- hol and ether. It was -fz0U.!.’1d that a considerable portion of -the dis-t_illa‘t’e in -the distillation -of Example I stuck to ‘thewalls. of-.. the distilling side arm and -in the ad'a"pterfand..»it. was found that this material had polymerized. .-It was -further -found that if a stream ‘of nitric oxide gas was introduced to the distillation ‘flask just above the surface of the distilland the polymerization of the distillate in the side arm and receiver was eliminated and the ester obtained in the monomeric form. Example I I Methyl alpha-cyano acrylate was prepared by a procedure similar to that of Example I using 23 grams of metallic sodium and 500 ml. of abso- lute methanol in the preparation of the sodium alcoholate. 100 grams of methyl cyanoacetate were then added to the sodium-methanol reac- tion mixture and the resulting mixture was heated on a steam bath for an hour and a half. The entire mixture of sodium derivative of methyl cyanoacetate in alcohol was then added to a fiaskcontaining 114 grams of chloro-methyl acetate. The temperature of the reaction mix- ture was maintained below 35° C. by means of an ice-saltbath. The resultant reaction mixture was poured into 700 “ml. of cold water and stirred. 5 -10 15' 20‘ 25 30» so in 45 -50 55 60 65 70 6 The water‘ and -on .,1aye‘rs were _«‘ei':‘traote‘¢1 acetoner. 'U'}'g3oi1«;s’t‘ahdin‘g-, a ‘water layer separated from" ‘the acetone solution was discarded. The acetone solution was then ‘dried and "the acetone *eva"p‘oratea ‘under The acetone extras , was dis “lied “under ‘vac- uum in the preseirce of nitric ='oxi'd'e gas 'an'd the distillate was -collected -in a "receiver imrnersed in a liquid nitrogen bath. The main fraction ‘dis- tillirfg ’