Conversion And Utilization Of High-boiling And Low-boling Residues From The Direct Synthesis Process Of Methylchlorosilanes

The paper is concerned with the research on treating and reusing the high-boling residue and low-boiling residue ,which formed in the direct process for the synethesis of dimethyldichlorosilane, by converting the high-boiling residue in the presence of hydrogen chloride to monosilane and by converting the high-boiling residue and low-boiling residue through disproportion reaction using A1C13 catalyst. The main object is to find optimal methods and ways to utilize the above by-product and make good economic ,social and ecological benefits.This paper includes two parts.Part one:Pilot investigating of high-boiling cleavaging with hydrogen chloride.In the 500t/a scale set for cleavage reaction, the orthogonal experiments were carried out to study the effects of reaction temperature, stirring rate,flux of HC1 and catalyst quantity and the factors of affecting the high-boiling cleavage ration and monosilane yeild were analyzed. The optimum reaction conditions were obtained:reaction temperature is 130 , stirring rate is 200r/min, catalyst quantity is 1.25~2%, flux of HC1 is 1.00L/h.At this condition, high-boiling cleavage ration is 86.71% and monosilane yeild is 67.81 %.The monosilane yeild can be increased by the recyling of high-boiling adsorbed mixtures.Part two: Disproportion reaction between high-boiling residue with low-boiling residue.AlCl3 is a good catalyst for the disproportion reaction. By investigating, the optimum conditions for the disproportion reaction were obtained: the quantity ration of reaction materials is 5: 1, reaction temperature is 280 , reaction time is 2h, catalyst quantity is 4%, stirring rate is 200~250r/min, The utilization of high-boling residue and low-boiling residue attain 75%, the content of dimethyldichlorosilane attain 49 % .Combining the result and the feature of disproportion reaction, we choose the 316 alloy materials for the design of reactor. Also the assemble project was designed.The composition of high-boiling residue and low-boiling residue have great influence composition of the above by-product.Based on the analysis results,the mechanism ofdisproportion reaction was investigated.We consider that chlorine escaping reaction, redistribution reaction, disproportion reaction and cleavge reaction were occurred between the high-boiling, low-boiling and monosilanes.At the end of the paper, assembled process of cleavage reaction of high-boiling residue and disproportion reaction were investigated.