Equilibrium Concentrations of SiHCl₃ and SiCl₄ in SiCl₄–H₂ System for Hydrogenation of SiCl₄ to SiHCl₃

Abstract

The equilibrium concentrations of SiHCl₃ and SiCl₄ in the SiCl₄–H₂ system are investigated on the basis of thermodynamic data for the corresponding pure compositions under specified thermodynamic parameters. Eight independent reactions in the SiCl₄–H₂ system for hydrogenation of SiCl₄ to SiHCl₃ are obtained. Furthermore, the factors (such as temperature, pressure, and feed mole ratio) influencing the equilibrium concentrations of SiCl₄ and SiHCl₃ are studied. Diagrams of the equilibrium concentrations of SiCl₄ and SiHCl₃ as a function of temperature, pressure, and feed mole ratio are presented. Finally, the optimal thermodynamic conditions in the SiCl₄–H₂ system for hydrogenation of SiCl₄ to SiHCl₃ are determined to be 1,100°C, 0.3 MPa, and a feed molar ratio of 4. Under these conditions, the conversion ratio of SiCl₄ to SiHCl₄ is about 25%, compared to a value of less than 20% in actual production.