The Study Of Novel Transition Metal Catalysts For Hydrosilylation Reaction Of Alkenes

Organosilicon compounds and organosilicon material are widely used in agricultural industry, emerging technology, national defense. And the hydrosilylation is one of the most important synthetic reactions for the formation of carbon-silicon bonds on a laboratory and an industrial scale. Many organic silicon compounds containing different functional groups can be synthesized vis this reactions. Currently, Speier's catalyst is a kind of homogeneous catalyst widely used in industrial hydrosilylation, but some defects are obvious. Firstly, the recovery of Speier's catalysts is very difficult. Secondly, hydrosilylation reaction catalyzed by platinum catalysts is not effective, in the case of silanes with electron-donating substiuents or olefins with electron-drawing substituents. Thus, the catalytic effects and recycling of hydrosilylation catalysts for silane coupling agent are investigated.To improve the yield of 3-chloropropyltrialkoxysilane, some transition metal catalysts were prepared and choosed. Different transition metal catalysts had a major effect on the yield of 3-chloropropyltrimethoxysilane, especially, the ruthenium catalysts had the better catalytic effect. Meanwhile, different transition metal catalysts had a major effect on the yield of 3-chloropropyltriethoxysilane, a maximum yield had been obtained with H₂IrCl6.6H₂O without the cocatalysts. The effects of process conditions on the yield of 3-chloropropyltrimethoxysilane had been investigated systematically. The optimized parameters were determined to be, temperature of 80oC, Ru quantity of 63μg·g-1, dropwise manner of adding 3-chloropropylene to trimethoxysilane, and the mole ratio of trimethoxysilane to 3-chloropropylene: 1.2¹.4. Under such condition, the hydrosilylation reaction could generate the product of 3-chloropropyltrimethoxysilane at an efficiency of as high as 96.7%.The heterogeneous catalysts (Pt/C) for hydrosilylation reaction was investigated. To improve the dispersion situation of Pt on activated carbon, the activated carbon was pretreated. The pretreatment can change the surface characteristics of activated carbon, increase the quantity of oxygen functional and oxygen concentration. It was found that Pt/CFO had the best catalytic effect on the 3-glycidoxypropyltrimethoxysilane. The effects of process conditions on the yield of 3-glycidoxypropyltrimethoxysilane had been investigated systematically. The optimized parameters were determined to be, reaction temperature 83oC, reaction time 1.5h, adding the trimethoxysilane to the allyl glycidyl ether, the amount of the catalyst 1.44×10-2mmol Pt. Under such condition, the hydrosilylation reaction can generate the product of 3-glycidoxypropyltrimethoxysilane at an efficiency of as high as 97.4%. The Pt/C-3 catalyst had a high stability, which could be reused for three times without loss in the catalytic activity. The Pt/C-3 catalyst had high catalytic activity on the hydrosilylation of aliphatic olefins with trimethoxysilane, but lower with triethoxysilane. Finally, the reaction mechanism for the hydrosilylation of trimethoxysilane with allyl glycidyl ether was discussed.To solve the defect of low activity of Pt/C catalyst on the hydrosilylation of triethoxysilane with olefins, a silica-supported nitrogenous platinum complex for this reaction was investigated. It was found that amino silane reacted with Si-OH of silica surface in the"SiO₂"-NH₂-Pt and"SiO₂"-2N-Pt complex. The effects of process conditions on the yield of 3-glycidoxypropyltriethoxysilane had been investigated systematically. Under the optimized process conditions, the hydrosilylation reaction could generate the product of 3-glycidoxypropyltriethoxysilane at an efficiency of as high as 93.8%. The"SiO₂"-NH₂-Pt and"SiO₂"-2N-Pt catalysts had a high stability, could be reused for four times without loss in the catalytic activity. Finally, the reaction mechanism for the hydrosilylation of triethoxysilane with allyl glycidyl ether catalysted by"SiO₂"-NH₂-Pt complex was discussed.To solve the defect of recycling ability of silica-supported nitrogenous platinum complex on the hydrosilylation of triethoxysilane with olefins, a SBA-15-supported nitrogenous platinum complex for this reaction was investigated for the first time. The major structure of SBA-15 had not been changed after amino functionization and loading Pt. Some functional molecules got into pore structures of SBA-15. The effects of process conditions on the yield of decyltriethoxysilane had been investigated systematically. The hydrosilylation reaction can generate the product of decyltriethoxysilane at an efficiency of as high as 94.1%. The"SBA-15"-NH₂-Pt and"SBA-15"-2N-Pt catalysts had a high stability, could be reused for six times without loss in the catalytic activity. This results was better than"SiO₂"-NH₂-Pt's. Also they had high catalytic activity on the hydrosilylation of aliphatic olefins with triethoxysilane. Finally, the reaction mechanism for the hydrosilylation of triethoxysilane with 1-decene catalysted by"SBA-15"-NH₂-Pt complex was discussed.