Patent ID: 7772349

Claim:
A process for preparing alkylpolyether-substituted mercaptosilanes of the general formula I, (X) m (X′) n (X″) o Si(—R 1 —SR 2 ) p (I) wherein p is 1, 2 or 3, m is 1, 2 or 3, n and o are 0, 1 or 2, and m+p+n+o is 4, the groups X are the same or different and X is an alkylpolyether group O—((CR 3 2 ) w —O—) v Alk, where v=1-40, w=1-40, R 3 independently at each occurrence is H, a phenyl group or an unbranched or branched alkyl group, Alk is a branched or unbranched, saturated or unsaturated, substituted or unsubstituted, aliphatic, aromatic or mixed aliphatic/aromatic monovalent C 1 -C 35 hydrocarbon group, the groups X′ are the same or different and X′ is a branched or unbranched alkoxy group, a branched or unbranched C 2 -C 25 alkenyloxy group, a C 6 -C 35 aryloxy group, a branched or unbranched C 7 -C 35 alkylaryloxy group, a branched or unbranched C 7 -C 35 aralkyloxy group, or a hydroxyl group (—OH), the groups X″ are the same or different and X″ indepedently at each occurance is a branched or unbranched alkyl group, R 1 is a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic/aromatic divalent C 1 -C 30 hydrocarbon group which is unsubstituted or substituted by heteroatoms, R 2 is CN, H or —C(Het)-Alk, where Het is a doubly bonded heteroatom O, S or NAlk and Alk has the definition given above, having a Hazen colour number of ≦250 mg Pt—Co/L, comprising reacting compounds of the general formula II, (X′) m+n (X″) o Si(—R 1 —SR 2 ) p (II) wherein X′, X″, R 1 , R 2 , m, n, o and p have the definitions given above, with m equivalents of the compounds of the general formula III, H—O—((CR 3 2 ) w —O—) v Alk (III) wherein R 3 , Alk, v and w have the definitions given above, in the presence of a proton-donating co-catalyst and a catalyst, and separating off liberated X′—H from the reaction mixture; wherein the proton-donating co-catalyst comprises an acidic ion exchange resin.