Organo-poly:silane(s) for silicon-carbide fibres and ceramics prodn. - by reaction of organo-di:silane(s) with organo-mono:silane(s) in presence of alkali metal alkoxide catalyst

摘要

Organopolysilanes (I) are produced by reaction of a disilane of formula R3Si2(OR1)3 (II), opt. mixed with a cpd. of formula R6-nSi2(OR1)n (III), with cpd(s). of formula (R3)4-mSi( OR1)m (IV) in the presence of cpd(s). of formula MOR2 (V); R = H or hydrocarbyl; R1 = alkyl; R2, R3 = hydrocarbyl; M = alkali metal; n = 4, 5 or 6; m = 1, 2, 3 or 4. Pref. disilanes of formula (III) are used, pref. R2Si2(OR1)4; mol. ratio (II):(III) is (30:70)-(90:10); amt. of silane (IV) is 5-40 wt.% and amt. of catalyst is 0.03-2.5 wt.%, w.r.t. total disilane. USE/ADVANTAGE - (I) are useful for prodn. of SiC fibres and ceramics, photoresist coatings, etc. The claims include: (a) a process for the prodn. of SiC fibres by spinning (I), pref. with addn. of a cpd. of formula R5O((R5O)2TiO)pTi(OR5)3 (with R5 = alkyl; p = 0-1000) and heating at 800-1400 deg.C under inert gas or vacuum and (b) a process for the prodn. of porous SiC ceramics, by mixing (I) with SiC powder, moulding and heating at 700-2200 deg.C under inert gas or vacuum. The invention provides a simple 1-stage process for the prodn. of (I) with mol. wt. 1000-2000, contg. no Si-bonded halogen and with functional gps. as required.