负载型铂催化剂催化苯乙烯硅氢加成反应

Hydrosilylation of Styrene Catalyzed by the Supported Platinum Catalyst

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。

Hydrosilylation of styrene with methyldichlorusilane was catalyzed by platinum on silica, T-Al2O3 and 5A- molecular sieve in polyetheneglyeol medium. The selectivity of the β-hydrosilylation product is 100%. As comparison the selectivity of β-hydrusilylation product is 55% if it was catalyzed by Speier catalyst. Among the three catalysts, the reusing of Pt/5A-moleeular sieve is bad and the induction time of Pt/γ-Al2O3 is very long, and both the induction time and the reusing of Pt/silica are very good. The high selectivity of these catalysts was explained.