Patent ID: 7041843

Claim:
A method for preparing a sulfide chain-bearing organosilicon compound, comprising the steps of: premixing a sulfide chain-bearing organosilicon compound having the general formula (1): (R 1 O) (3−p) (R 2 ) p Si—R 3 —S m —R 3 —Si(OR 1 ) (3−p) (R 2 ) p (1) wherein R 1 and R 2 each are a monovalent hydrocarbon group of 1 to 4 carbon atoms, R 3 is a divalent hydrocarbon group of 1 to 10 carbon atoms, m has an average value of 3 to 4, and p is 0, 1 or 2, with a halogenoalkyl group-bearing organosilicon compound having the general formula (2): (R 1 O) (3−p) (R 2 ) p Si—R 3 —X (2) wherein R 1 and R 2 each are a monovalent hydrocarbon group of 1 to 4 carbon atoms, R 3 is a divalent hydrocarbon group of 1 to 10 carbon atoms, X is a halogen atom, and p is 0, 1 or 2, and sulfur, adding anhydrous sodium sulfide represented by Na 2 S to the premix, and allowing reaction to take place for thereby forming a sulfide chain-bearing organosilicon compound having the general formula (3): (R 1 O) (3−p) (R 2 ) p Si—R 3 —S n —R 3 —Si(OR 1 ) (3−p) (R 2 ) p (3) wherein R 1 and R 2 each are a monovalent hydrocarbon group of 1 to 4 carbon atoms, R 3 is a divalent hydrocarbon group of 1 to 10 carbon atoms, n has an average value 2 to 3, exclusive of m=n=3, and p is 0, 1 or 2, while minimizing formation of a monosulfide-bearing organosilicon compound with n=1 to a level of at most 1 mol %.