氯硅烷中甲基二氯硅烷的转化反应工艺

Conversion reaction process of methyldichlorosilane in chlorosilane

为了除去多晶硅原料中主要含碳杂质甲基二氯硅烷,通过催化反应将其转化为高沸点物质甲基三氯硅烷。采用浸渍法制备了Pd/Al2O3催化剂,将其用于催化甲基二氯硅烷的转化。采用XRF、XRD、BET、XPS、H2-脉冲化学吸附技术对催化剂物化性质进行表征。以四氯化碳为氯源,利用固定床反应器,对比了Pd/Al2O3催化剂、树脂A催化剂及Al Cl3/Al2O3催化剂的催化效果。重点考察了反应温度、反应物物质的量比、反应液时空速及催化剂稳定性对甲基二氯硅烷转化率的影响,得到了最佳工艺条件。相比于树脂A催化剂和Al Cl3/Al2O3催化剂,Pd/Al2O3催化剂具有更好的催化效果;在反应温度为140℃、n(甲基二氯硅烷)∶n(四氯化碳)=3∶1、反应液时空速为5.0 h^–1时,甲基二氯硅烷转化率最高可以达到69.76%。

In order to remove the main carbon impurity methyldichlorosilane in the polysilicon raw material, a catalytic reaction was used to convert it into a high boiling point substance, methyltrichlorosilane. Pd/Al2 O3 catalyst was prepared by impregnation method and used to catalyze the conversion of methyldichlorosilane. Its physicochemical properties were characterized by XRF, XRD, BET, XPS, and H2-pulse chemisorption techniques. The catalytic effects of Pd/Al2 O3 catalyst, resin A catalyst, and Al Cl3/Al2 O3 catalyst were compared using carbon tetrachloride as chlorine source in a fixed-bed reactor. The effects of reaction temperature, molar ratio of reactants, liquid hourly space velocity, and catalyst stability on the conversion of methyldichlorosilane were investigated. The results showed that Pd/Al2 O3 catalyst had better catalytic effect than resin A catalyst and AlCl3/Al2 O3 catalyst. Under the optimal process conditions of reaction temperature 140 ℃, n(methyldichlorosilane) : n(carbon tetrachloride)=3 : 1, and liquid hourly space velocity 5.0 h^–1, the maximum conversion of methyldichlorosilane could reach 69.76%.