GB1231521A - - Google Patents

Abstract

1,231,521. Cyanoacetic acid preparation. CHRIS-CRAFT INDUSTRIES Inc. 30 April, 1969 [5 Aug., 1968], No. 22062/69. Heading C2C. In a process for the production of cyanoacetic acid, in which an aqueous solution of chloroacetic acid is neutralized with sodium carbonate to form sodium chloroacetate which in turn is reacted in a nucleophilic substitution with an alkali metal cyanide and the resultant cyanoacetate is then acidified to form an aqueous reaction mixture comprising cyanoacetic acid and the respective salts formed in such reaction sequence, improvements are made which comprise conducting the nucleophilic substitution reaction in the presence of a 3-12 C alkanol and at a temperature in excess of 80‹ C. to accelerate the reaction while substantially precluding undesirable side reactions, thereby increasing the yield of the cyanoacetate and decreasing the tendency of the reaction to form colour bodies, and extracting the acidified, aqueous reaction mixture with an alkanol which contains from not less than 3 to 12 carbon atoms and which is substantially insoluble in saturated brine, using the aqueous reaction mixture in such a manner that the amount of salts in such reaction mixture substantially saturate the amount of water present, thereby permitting substantially all of the cyanoacetic acid to be extracted by the alkanol. The neutralization may be carried out by using less than the stoichiometric amount of Na 2 CO 3 to achieve a pH of 4-5 and removing substantially all the residual CO 2 from the partially neutralized mixture under vacuum, and then completing the neutralization with NaOH before using the CICOONa in the nucleophilic substitution. The cyanoacetic acid may be esterified or converted into its amide by conventional procedures.