搅拌床中甲基氯化铝法甲基三氯硅烷转化反应

针对“直接法”合成二甲基二氯硅烷过程中产生的副产物甲基三氯硅烷（M₁），在搅拌床反应器中，对甲基氯化铝法甲基三氯硅烷气固相转化反应进行了系统研究.结果表明，该反应经历了约100 min的诱导期后，产物组成趋于稳定.机械搅拌促进了铝粉表面氧化膜的去除和表面更新，使得转化反应无须外加催化剂.提高搅拌速度和反应温度有利于转化反应程度的提高，但存在一个最佳值.原料组成MeCl/M₁摩尔比（m）对转化反应的进行程度和产物组成影响较大，当m＜2.0时，M₁转化率较低，转化产物主要为二甲基二氯硅烷（M₂）和三甲基氯硅烷（M₃）;当m＝2.0时，产物主要为M₃;当m＞2.0时，M₁转化率较高，主要产物为四甲基硅烷（M₄）.采用SEM对反应前后Al粉粒子表面形态进行了表征，探讨了该气固相转化反应的机理和历程.

Conversion of methyltrichlorosilane in stirred bed reactor by methylalumminumchloride method

This paper focuses on the reaction technique of converting methyltrichlorosilane, the main by-product in the direct synthesis of dimethyldichlorosilane, to more valuable methylchlorosilanes.The conversion reaction of methyltrichlorosilane in a stirred bed reactor by the methylaluminumchloride method with aluminum powder and methylchloride as raw materials was systematically investigated.It was found that after an introduction period of about 100 min, the reaction reached a steady state with good activity in the absence of catalysts by the aid of mechanical stirring in the reactor which promoted the elimination of oxidized layer on the surface of the aluminum powder and speeded up the surface renewal process.Increasing the stirring speed and raising the reaction temperature to the optimum levels were favorable to the conversion reaction.The molar proportion of methyl chloride to methyltricholrosilane (m) in the feed had great effect on the reaction conversion and product composition.The concentrations of dimethyldichlorosilane and trimethylchlorosilane in the product were relatively higher while the reaction conversion of methyltrichlorosilane was lower when m<2.0,the trimethylchlorosilane was the main conversion product when m=2.0, and tetramethylsilane became the main product at a higher reaction conversion of methyltrichlorosilane when m>2.0.The reaction mechanism was discussed by analysing the SEM surface morphology of the aluminum powder before and after reaction.