硅和四氯化硅耦合加氢反应体系的热力学分析

摘要

Based on the principle of Gibbs free energy minimization, the thermodynamic analysis on the chemical reaction system of the co-hydrogenation of silicon tetrachloride and silicon was carried out.Through the analysis on the composition distribution of chemical equilibrium products,the main products of the reaction system were confirmed as HSiCl3 (TCS), H2SiCl2(DCS) , and HCl,and three independent reactions were constructed at the same time.The relations of heat of reaction (ΔHθm),free energy (Δ rCθm), and equilibrium constant (Kθp) versus temperature were discussed.The calculation was made under the conditions of temperature at 673~923 K,pressure range at 101.325~2 026.5 kPa,and raw material amount-of-substance ratio (H2/SiCl4) at 1 ~5.Results showed the equilibrium conversions of SiCLt and SiHCl3 yield reduced with the increasing temperature of reactions of producing TCS and DCS;high pressure and proper raw material mix ratio(amount-of-substance ratio of H2 to SiCl4) were favorable for the enhancement of S1CI4 conversions and SiHCl3 yield.%基于Gibbs自由能最小原理,对硅和四氯化硅(SiCl4,STC)耦合加氢反应体系进行了热力学分析.通过化学平衡产物组成分布的分析,确定了反应体系主要产物为三氯硅烷(HSiCl3,TCS)、二氯硅烷(H2SiCl2,DCS)、盐酸(HCI),并构造了3个相应的独立反应,讨论了对应的反应热(△HHmθ)、自由能(△rGmθ)和平衡常数(kpθ)与温度的关系.计算所采用的温度为673～923 K,压力为101.325～2 026.5 kPa,原料H2与SiCl4物质的量比为1～5.结果表明,生成TCS和DCS的反应为体系随着温度升高,四氯化硅平衡转化率及三氯硅烷产率降低；高压和适中的原料配比(H2与SiCl4物质的量比)有利于四氯化硅转化率及三氯硅烷产率的提高.