Patent ID: 8008524

Claim:
A process for the preparation of an aqueous solution of a salt of a thiocarboxylic acid which comprises reacting an aqueous solution of a sulfide and/or hydrosulfide with an acid halide and/or acid anhydride in the presence of a phase transfer catalyst to provide the aqueous solution of thiocarboxylic acid salt, wherein the structures of the sulfide, hydrosulfide, acid halide and acid anhydride are represented by the formulae: M2S (6) MSH (7) GI(-Y-L)a (8) wherein each occurrence of M is an alkali metal; ammonium; or a mono-, di-, or tri-substituted ammonium; each occurrence of L is a halogen atom, sulfonate group, sulfinate group, or carboxylate group; Y is carbonyl, C(═O); each occurrence of R is chosen independently from the set of groups comprising hydrogen, alkyl groups, alkenyl groups, alkynyl groups, aryl groups and aralkyl groups with each R containing from 0 to about 30 carbon atoms; each occurrence of G 1 is independently R or a polyvalent group derived from an alkyl, alkenyl, aryl or aralkyl group, containing from 1 to about 40 carbon atoms, each occurrence of the subscript a is independently an integer from 1 to 6 and wherein the phase transfer catalyst is represented by the formula: (R 1 R 2 R 3 R 4 Q + ) n A −n (9) wherein each separate occurrence of R 1 , R 2 , R 3 and R 4 , is, independently, an R, wherein R is a hydrogen, an alkyl, an alkenyl, an alkynyl, an aryl or an aralkyl containing from 0 to about 30 carbon atoms; Q is nitrogen or phosphorus; and A −n is a monovalent or polyvalent anion where the minus sign denotes that the species is an anion, and n denotes the number of negative charges on the anion; and, wherein the subscript n is a positive integer of from 1 to about 6.