Effects of double promoters on direct synthesis of triethoxysilane in gas-solid stirred fluidized bed

The reaction of silicon with ethanol was carried out in a gas-solid stirred fluidized bed, with cuprous chloride prepared by a wet process as the catalyst. The effect of hydrogen fluoride and ethyl chloride addition on formation of triethoxysilane in the direct process was described and discussed. The catalytic activity was evaluated using online gas chromatography, X-ray diffraction and scanning electron microscopy to study the contact mass. The results show that the promoters hydrogen fluoride and ethyl chloride not only supplemented anions, but also depressed the catalytic activity of metallic copper. The comparison of technical-grade silicon and polycrystalline silicon showed many differences in reactivity, reaction rate and induction period. Furthermore, the yield, selectivity of triethoxysilane and reaction rate were improved significantly with additions of hydrogen fluoride and ethyl chloride.