Patent ID: 6140524
Filing Date: 2000-10-31
Classification: C07F

Abstract:
A method for preparing a mixture of short-chain polysulfide silanes represented by formula (1):(RO).sub.3 SiC.sub.3 H.sub.6 S.sub.n C.sub.3 H.sub.6 Si(OR).sub.3( 1)wherein R is methyl or ethyl and n is a positive number having a distribution, the average of the distribution being 2.2.ltoreq.n.ltoreq.2.8, said method comprising the step of reacting polysulfides represented by the following general formula (2) or (3):M.sub.2 S.sub.n ( 2)NS.sub.n ( 3)wherein M is an alkali metal or ammonium, N is an alkaline earth metal or zinc, and n is as defined above, with a halogenopropyltrialkoxysilane of the following general formula (4):(RO).sub.3 SiC.sub.3 H.sub.6 X (4)wherein X is a halogen atom and R is as defined above, in an alcohol, said polysulfides of formula (2) or (3) being prepared by reacting a metal sulfide represented by M.sub.2 S or NS wherein M and N are as defined above with sulfur in an alcohol, and isolating and adjusting the obtained metal polysulfide mixture so that free sulfur is absent and the average of distribution of n falls in the range of 2.2 to 2.8.