乙炔和甲基二氯硅烷的硅氢加成反应研究——Ⅰ. 金属铂胶体的制备及其催化性能

STUDY ON HYDROSILYLATION OF ACETYLENE AND METHYLDICHLOROSILANE——PREPARATION OF PLATINUM MATAL COLLOID AND ITS CATALYTIC BEHAVIOR

通过直接水解的方法合成了聚甲基乙烯基硅氧烷，首次以此作为保护剂，加热二甲苯溶剂下的氯铂酸，得到了稳定的金属铂胶体。通过观察形成时及进行硅氢加成反应４ｈ后的胶体粒子的ＴＥＭ，考察了它和原位氧化还原法得到的铂胶体的稳定性，并对比考察了他们的硅氢加成反应活性和一次加成选择性。结果表明，此保护剂存在下的铂胶体对乙炔和甲基二氯硅烷的硅氢加成反应具有良好的反应活性和稳定性。

Polymethylvinylsiloxane is synthesized from the hydrolytic polycondensation reaction of methylvinyldichlorosilane.Its IR spectrum is given.With the polysiloxane as colloid protective agent,the platinum metal colloid(B) is prepared by the thermal decomposition of chloroplatinic acid in xylene solvent at 383 K.The same process can only get platinum metal precipitate(A) without the pressence of polysiloxane.The platinum colloid(C) can also be prepared by reduction in situ in hydrosilylation.Precipitate A,colloid B and colloid C have been used as catalyst for hydrosilylation of acetylene and methyldichlorosilane.The conversion of methyldichlorosilane is 27.8%,100% and 100%,respectively.And the selectivity for the first additive reaction is 45.1%,97.3% and 97.5%,respectively.TEM photographs of colloid B and colloid C for hydrosilylation in different time have been given.TEM results show that colloid B is stable and the colloid particle size has not changed obviously in the reaction.The colloid C is not so stable as colloid B for its particle size gets larger in the reaction.