Direct synthesis of silicon compounds from metallic silicon

根据带头人和同事提出的以氯化铜为催化剂，由金属硅和甲醇直接合成三甲氧基硅烷的反应机理，进行了金属硅与氯化氢的反应。当该反应在丙烯存在下进行时，生成有机硅化合物。通过考察催化剂用量、反应温度、丙烯与氯化氢的摩尔比等因素，得到了最佳反应条件。例如，将金属硅和氯化铜(I)粉末的物理混合物(铜=5wt.%)加载到常压下运行的固定床流动反应器中，并在723K下在氦气中热处理10min。然后，向反应物中加入氯化氢(10 mmolh^-1)和丙烯(5 mmolh^-1)。反应5h得到异丙基二氯硅烷和丙基二氯硅烷，选择性分别为13%和3%，金属硅的转化率为87%。其他含硅化合物有三氯硅烷、二氯硅烷和四氯硅烷。就像由金属硅和甲醇直接合成三甲氧基硅烷一样，反应通过在硅表面形成的表面硅烯进行：硅烯与丙烯反应，最终形成有机硅化合物

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