The Research And Design For Green Synthesis Of Tetraethoxy Silane

Tetraethoxysilane, commonly known as TEOS, is an important silicone compounds. At present, the process widely used in industrial production is silicon tetrachloride.However, due to byproduct hydrogen chloride gas, this process can easily cause environmental pollution. Meanwhile, affected by the resource reduction, price increasing of silicon tetrachloride. It is a trend that the process will be replaced by new technology.In this paper, new process with silicon powder as a raw material for methoxylation, and transesterification is proposed. It is a green synthesis of tetraethoxysilane with no produce byproducts, and no poison.Firstly, the Silicon powder was synthesized directly by methoxy tetramethoxysilane with sodium methylate as catalyst According to the study of kinetic model, we explored the effect of different catalyst ratio, methanol flow, silicon particle size, temperature and other conditions on the reaction. Research shows the volume of sodium methylate and the methanol flow in catalyst:The flow of methanol is3.3; Methanol can not only participate in the reaction, but the excess methanol was also entrained tetramethoxysilane to maintain the continuity of the reaction system. Small particles of Silicon powder are carried out to facilitate the reaction.Secondly, in a certain temperature range, the reaction kinetics were established and we can see that higher temperatures are carried out to facilitate the reaction. k=1.38x1016·e(-19964)/T。This article has simulated for the formation and accumulationuses of tetramethoxysilane with the model.The result laid the design of process.Thirdly, the balance test of transesterification reaction was conducted. Studies have shown that high temperature and sodium methoxide catalyst can promote the transesterification reaction. The transesterification reaction equilibrium is the key factor.The fourth, the equilibrium constant is analyzed and calculated by changing the ratio of ethanol in the transesterification. The comparison table between the methanol content of tower reactor and product quality standards is obtained and the relationship between product quality standards and the number of trays tower of transesterification is simulated.The Fifth, relationship of methanol content of the top of transesterification tower and the flow of ethanol and plate numbers has been calculated for theoretical basis of the whole process.Finally, foundation design of the annual yield of5,000tons’ tetraethoxysilane has been conducted. And the process flow diagram with the control point, material balance diagram and layout chart are completed according to material balance and energy balance.