US Patent 7288667 Preparation of sulfide chain-bearing organosilicon compounds

A sulfide chain-bearing organosilicon compound having the average compositional formula:(R1O)(3-p)(R2)pSi—R3—S—(R4—Sm)q—R4—S—R3—Si(OR1)(3-p)(R2)pis prepared at low costs and in high yields by reacting a halogen-terminated organosilicon compound having the formula: (R1O)(3-p)(R2)pSi—R3—S—R4—X, sulfur, and optionally a halide having the formula: X—R4—X with an aqueous solution or dispersion of a sulfide M2S or hydrate thereof in the presence of a phase transfer catalyst. R1 and R2 are monovalent C1-4 hydrocarbon groups, R3 and R4 are divalent C1-10 hydrocarbon groups, m has an average value of 2-6, p is 0, 1 or 2, q is 1, 2 or 3, X is halogen, and M is ammonium or alkali metal.