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分别研究了硅胶、γ-Al2O3和5分子筛负载聚乙二醇络合铂催化剂催化苯乙烯与甲基二氯硅烷的硅氢加成反应,发现这三种催化剂对β-加成产物的选择性为100%,不生成α-加成产物。而用Speier催化剂对β-加成产物的选择性为55%,产生α-加成产物。在这三种催化剂中,分子筛作载体的催化剂重复使用性较差,Al2O3作载体的催化剂诱导期较长,而硅胶作载体的催化剂比其它两种催化剂重复使用性好,且诱导期也较短,因此具有明显的优越性。文中还初步探讨了这三种催化剂出现高选择性的原因。
The hydrosilylation reaction of styrene with methyldichlorosilane catalyzed by polyethylene glycol complexed with silica gel, γ-Al2O3 and 5 zeolite was studied respectively. The selectivity of β-adducts Is 100%, no α-addition product is formed. While the Speier catalyst was 55% selective for the β-adduct, producing an α-adduct. Among the three catalysts, the molecular sieve as a catalyst has poor reusability and the catalyst for Al 2 O 3 carrier has a longer induction period. However, silica as a carrier has better reusability than the other two catalysts and has a shorter induction period , So has obvious advantages. The article also tentatively explored the reasons for the high selectivity of these three catalysts.