GB851684A - Improvements in the production of acid chlorides - Google Patents

Abstract

Carboxylic acid chlorides are prepared by reacting a compound of formula (R4)(R6)C:C (R5)COOH, where R4, R5 and R6 represents hydrogen, halogen, or aliphatic, araliphatic or aromatic radicals, or, in pairs, common members of a cycloaliphatic ring, with phosgene at temperatures below 150 DEG C and in the presence of a compound of formula R1CO.N(R2)(R3), where R1 represents hydrogen or an alkyl, cycloalkyl, aralkyl, lower alkoxy or lower dialkylamino radical, R2 and R3 represent alkyl, aralkyl, or aryl radicals, and where R1, R2 and R3 may represent, in pairs, common members of a heterocyclic ring containing the carbonamide nitrogen atom. "Lower" means containing up to 4 carbon atoms. When R4 is hydrogen and R5 and R6 are hydrogen, halogen, aliphatic or araliphatic radicals or common constituents of a cycloaliphatic ring, and the reaction temperature is below about 100 DEG C, the products are b -chlorocarboxylic acid chlorides ; if the resulting reaction mixture is heated to above 100 DEG C, an a ,b -unsaturated carboxylic acid chloride is obtained. When R4, R5 and R6 are aliphatic, araliphatic or aromatic radicals, or, in pairs, common constituents of a cycloaliphatic ring, and where R5 may also be hydrogen or chlorine, and where R6 may also be hydrogen when R4 is aromatic, and at a reaction temperature below 100 DEG C, the product is an a ,b -unsaturated carboxylic acid chloride. Suitable compounds of the above two general formulae are listed. Specification 401,643 is referred to.