Study On The Direct Synthesis Of Methylchlorosilanes And The Evaluation Of The Catalysts

The direct synthesis of methylchlorosilanes (MCS) was studied by the use of Si powder and CH₃Cl catalyzed in the fluidized bed or fixed bed reactors. The crude methylchlorosilanes obtained was characterized by ¹H-NMR to determine the selectivity.Five types of copper catalysts were used to investigate their effects on the MCS reaction. The results revealed that size of the silicon powder had different effect on the selectivity catalyzed in for methylchlorosilanes under different conditions.When CuCl was used as catalyst, the selectivities for methylchlorosilanes between in fluidized bed reactor and fixed-bed reactor were compared. It is found that in fluidized bed reactor, the selectivity of Di is higher than that in the fixed-bed reactor, but the selectivity of Tri is lower, and the selectivity of MH is similar to that in the fixed-bed reactor.When the commercial catalyst 4 was used, the influence of reaction time on the selectivity of methylchlorosilanes in the fixed-bed reactor was investigated. The results showed that the selectivity of Di reached a maximum at the reaction time of 12h, possibly due to the decomposition of CH₃Cl and formation of by-product carbon.