Study of Catalytic Conversion of Organosilicon Compounds

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Both in laboratories and industries, reactions of organosilane are usually performed in a homogeneous liquid phase using metal halides and transition metal complexes. The development of fundamental chemistries of Si compounds in heterogeneous catalysis is quite attractive and important challenge. Hence the activation process and the catalytic conversion of alkylsilanes were examined.1. On the initiation step of alkylsilane activation as a model of hydrocarbon activationCatalytic conversion of hydrocarbons in superacidic media is initiated by proton addition yielding a 3c-2e or 5-coordinated intermediate, which decomposes to carbenium ion and hydrogen or alkanes such as methane. NMR and XPS have directly evidenced the existences of such intermediates and the following process. On solid surface like solid acid, it is hard to obtain them since superacidic solid acid is rare to activate saturated hydrocarbons under mild condition. Si-H in organosilane is more active than C-H bond in alkane … More s. Thus We examined the initiation step of alkylsilanes from the hydrogen evolution and the HD content when the silane was contact With deuterated solid acid. As a result, we found (1) hydrogen evolution occurs around room temperature, (2) amount of hydrogen molecule was in the order of μmol g-1, and (3) there are two types of hydrogen evolution process, one is ionic and the other is non- ionic.2. Catalytic hydrosilylation of aliphatic ketonesTitle reaction was examined by using triethylsilane (E3) and diethylsilane (E2) with diethylketone and cyclohexanone at room temperature in a glass batch type reactor. The catalyst was CaO and Al2O3. We obtained silylether from E2 and ketones as a single product in 70-90 % yield after 20-40 h reaction. By-products were the products of aldol condensation of ketone itself. By decreasing the E2/ketone ratio, the yield decreased which indicates a strong interaction of ketones with the catalyst surface. E3 was totally inactive, probably because of the steric hindrance on solid surface.These results are the first finding of the heterogeneous catalytic conversion of organosilicone compounds in the world. Less