Studies On The Catalytic Cleavage Of The High-boiling Residue Over AlCl₃-grafted MCM-41 And The Catalytic Hydrodechlorination Of Silicon Tetrachloride Over (Co,Mo)/C

In the first part of this thesis, Mesoporous MCM-41 silica immobilized aluminum chloride was employed as a new catalyst for cleaving high-boiling residue to monosilanes. The parent and AlCl3-grafted MCM-41 samples were characterized by X-ray powder diffraction, N2 sorption and EDAX. The nature and concentration of the acid sites of AlCl3-grafted MCM-41 samples were monitored by in situ IR using pyridine as a probe molecule. The result of catalytic cleavage reveals that the as-synthesized catalysts possess considerable activity in the catalytic decomposition reaction and high selectivity to monosilanes. The AlCl3-grafted MCM-41 catalyst can be used for the cleavage of high-boiling residue under atmospheric pressure. The influence of reaction time on the performance of the catalyst was also investigated. The conversion of high-boiling residue and yield to monosilanes can reach 70.5% and 63.4% over the AlCl3-grafted MCM-41 catalyst, respectively.In the second part of this thesis, Co/C, Mo/C, and Co-Mo/C were prepared by impregnation method for hydrodechlorination of silicon tetrachloride to trichlorosilane under atmospheric pressure. All the catalysts were characterized by X-ray powder diffraction, N2 sorption, TPR. The influence of reaction temperature, content of active component, the ratio of H2:SiCl4 on the performance of the catalyst was also investigated. At last, the comparison of catalytic activity among such three catalysts was investigated; the results revealed that the catalytic activity of Co/C for hydrodechlorination of silicon tetrachloride to trichlorosilane was the highest. The conversion of silicon tetrachloride to trichlorosilane can reach 5.2% over the Co/C catalyst.