Patent ID: 7528273

Claim:
A process for the preparation of thiocarboxylate silane represented by the formula: G 1 [-Y—S-G 2 (SiX 3 ) c ] a (2) which comprises reacting an aqueous solution of salt of thiocarboxylic acid represented by the formula: G 1 (-Y—S − M 30 ) a (4) with a haloalkyl silane represented by the formula: L f G 2 (-SiX 3 ) c (5) with continuous agitation, at a temperature of between 40° C. and 95° C. and in the presence of a catalytically effective amount ranging from 1 part per million to 3 weight percent of alkylguanidinium salt phase transfer catalyst represented by the formula: to provide thiocarboxylate silane containing less than 12 weight percent of siloxane-type by-product(s), wherein G 1 is R wherein R is chosen independently from the set of groups comprising hydrogen, alkyl groups that may or may not contain unsaturation, alkenyl groups, alkynyl groups, aryl groups, and aralkyl groups, with each R containing from 0 to 30 carbon atoms; G 2 is chosen from the group consisting of —CH 2 —, —CH 2 CH 2 —, —CH 2 CH 2 CH 2 — and —CH 2 CH(CH 3 )CH 2 —; Y is carbonyl, C(═O): each occurrence of X is independently a member selected from the group consisting of RO—, and —R, with the proviso that at least one X is not —R; L is a halogen; each R 1 , R 2 , R 3 , R 4 , R 5 and R 6 is a primary alkyl radical containing 1 to 6 carbon atoms; X − is chosen from the group consisting of chloride and bromide; M + is an alkali metal cation; the subscript a is 1; the subscript c is 1; the subscript f is 1; and the subscript n is 1.