Synthesis And Property Study On Heterogeneous Hydrosilylation Catalyst

The hydrosilylation reaction,the addition of a Si-H unit to a C-C double bond to form an alkylsilane,is one of the most important methods for the syntheses of organosilicon compounds.Generally,the Speier’s catalyst and Karstedt’s catalyst which are all homogeneous are known to be efficient catalysts for the hydrosilylation reactions,but they are difficult to recover.In order to solve the problem of separating the catalyst from the reaction mixture,some solid-supported catalysts were developed quickly.Most of these traditional heterogeneous catalysts are separated by decantation or filtration.however,this way is not an advantage in terms of cost control,particularly for large-viscosity macromolecular system and large-scale industrial production.Based on the above problem,this work aims to design a recyclable catalyst for hydrosilylation reaction using superparamagnetic core-shell NPs,which can be easily separated by magnetic force.In the actual study,two kinds of catalysts were successfully developed.they are as follows.This work designed a solid-supported catalyst with novel structure noted as Pt/SiO2/Fe3O4.It was found that this as-synthesized catalyst is efficient and stable for the hydrosilylation of allyl polyether with low-hydrogen-content silicone oil.The conversion rate towards this reaction can reach 88.70%.It could be separated by magnetic force and reused seven times without any appreciable loss in the catalytic activity.Another solid-supported catalyst noted as Pt/Vinyl/SiO2/Fe3O4 was conveniently prepared in this work.It was found that the complex is an efficient catalyst for the hydrosilylation of allyl polyether with low-hydrogen-content silicone oil and could be separated by magnetic force.The conversion rate towards this reaction can reach 92.2% and no appreciable decrease in activity was observed after four cycles of the catalytic reaction.In this work,PtNi/SiO2/Fe3O4 was synthesized through the method of alloying to further improve the catalytic activity of Pt/SiO2/Fe3O4.The excellent durability and reusable property of these special catalysts were achieved in the present work,which can drastically lower the cost of hydrosilylation reaction in industry.