Direct synthesis of silicon compounds from metallic silicon

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Based on the reaction mechanism proposed by the head investigator and coworkers for the direct synthesis of trimethoxysilane from metallic silicon and methanol using copper (I) chloride as the catalyst, the reaction of metallic silicon with hydrogen chloride was carried out. When this reaction was conducted in the presence of propene, organosilicon compounds were formed. By examining the reaction factors such as amount of catalyst, reaction temperature, and molar ratio of propene to hydrogen chloride, optimum reaction conditions were obtained.For example, physical mixture of metallic silicon and copper (I) chloride powders (Cu= 5wt.%) was loaded in a fixed-bed flow reactor operating under the atmospheric pressure, and was heat-treated at 723 K for 10 min in a helium stream. Then, hydrogen chloride (10 mmol h^<-1>) and propene (5 mmol h^<-1>) were fed to the reactcr. The reaction for 5 h gave isopropyldichlorosilane and propyldichlorosilane with selectivity of 13 and 3%, respectively, the conversion of metallic silicon being 87%. Other silicon-containing compounds were trichlorosilane, dichlorosilane, and tetrachlorosilane.Just as same as the direct synthesis of trimethoxysilane from metallic silicon and methanol, the reaction proceeds via surface silylene formed on the silicon surface : silylene reacts with propene to finally form organosilicon ccmpounds