将乙烯基三乙氧基硅烷(VTES)改性的纳米SiO2与氯铂酸(H2PtCl6·6H2O)反应,通过乙烯基与Pt的络合作用制备SiO2负载Pt催化剂。对催化剂的Pt负载量和结构进行表征,探究了VTES与纳米SiO2质量比对催化剂Pt负载量的影响,并通过硅氢加成反应考察了催化剂的催化活性和重复利用性。结果表明,通过VTES改性的SiO2可以负载更多、更稳定的Pt催化剂。所制备的Pt/SiO2-Vi5催化剂Pt负载量为0.504%。将其用于二氯甲基硅烷与1-辛烯的硅氢加成反应中,当反应温度为80℃、反应5h时,转化率可达95.22%,β-加成产物的产率为95.11%,且催化剂至少可进行4次循环反应而催化活性无明显损失。
SiO2 supported Pt catalysts were prepared via the reaction of nano-SiO2 modified by vinyltriethoxysilane(VTES) and chloroplatinic acid hexahydrate(H2PtCl6·6H2O) through the complexation between the vinyl groups and Pt.Pt content and structure of the catalysts were characterized.Effect of the mass ratio of VTES to SiO2 on Pt content were investigated,and the catalytic activity and recyclability of the catalyst were examined by a hydrosilylation reaction.Results showed that SiO2 modified by VTES could support more amount and stable Pt catalyst,with Pt content of the Pt/SiO2-Vi5 catalyst reached 0.504%.The Pt/SiO2-Vi5 catalyst displayed high activity in the hydrosilylation of dichloromethylsilane with 1-octene.When the reaction was conducted at 80℃ for 5h,the conversion of the reactant and yield of β-adduct reached 95.22% and 95.11%,respectively.Furthermore,the recovered catalyst could be recycled and reused for at least four times without any significant loss in activity.
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