hydrophobising finely divided oxide(s) of metals or silicon - by treatment with organo-silicon cpds. and ammonia gas

摘要

The completely dry oxide is treated with an organosilicon cpd. (I) in a fluidised bed at 700-1000 deg.C for up to 60 sec. in an inert gas stream, and before, during or after this treatment, the material is treated with dry NH3 gas for at most 60 sec. (I) is e.g. a cpd. Rn(SiOR')4-n, with R=1-12C alkyl or aryl and R'=1-8C alkyl and n=1-3; a cpd. R2Si(OR')2 where R=1-8C alkyl or aryl and R'=1-8C alkyl; a cpd. RSi(OR')3 where R=1-12C alkyl or aryl and R'=1-8C alkyl; a cpd. R-Si(X)(Y)- (O-Si(R)(Y)-)n O-Si(X)(Y)-R in which X is R or OR', Y is R or OR', R is 1-8C alkyl or aryl and R' is 1-8C alkyl, and n=0 or 1; cpds. R-Si(OR') (R) -O(-Si(R)(R)-O)n-Si(OR')(R)(R) where R and R' are as above and n=0-2; cpd. R-Si(OR')(OR') -O-(Si (OR')(R)-O)n-Si(OR')(OR')(R) in which R=1-12C alkyl or aryl, R'= 1-8C alkyl and n=0 or 1; cpd. of formula (II) where R is 1-12C alkyl or aryl and n=3 or 4; cpds. (R)3Si(-O-Si(R)2)n-O-Si(R)3 where R=methyl, 2-4C alkyl or aryl and n=0-8; or cpds. of formula (III) where R=(m)ethyl and n=3-5. The process is carried out at moderate temps. and pressures so that relatively cheap appts. can be used, and a hydrophobe prod. is obtd. which is largely free from volatile reaction prods. The prods. are useful e.g. as fillers in silicone rubbers.