Ultrapurification of SiCl4 by photochlorination in a bubble column reactor

Abstract

AbstractThe development and performance of a bubble column photoreactor for ultrapurification of SiCl4 is described. Trichlorosilane (SiHCl3), the principle contaminant in SiCl4 commercially available for use in optical fiber manufacture, is converted to SiCl4 and HCl by UV‐initiated photochlorination. Studies of the homogeneous photochlorination kinetics and of Cl2 gas absorption in a bubble column were undertaken. In addition, an extensive set of data was collected from continuous‐flow bubble column reactor (BCR) runs. The rate of photochlorination in the BCR was found to be mass‐transfer‐limited. A simple model of BCR performance, incorporating the effect of Cl2 mass transfer rate enhancement by chemical reaction, was tested that agrees well with the experimental data. The BCR was found to be operable over a wide range of SiHCl3 concentrations and SiCl4 feed rates, and capable of lowering the concentration of SiHCl3 in product to below measurable levels (<1 ppm).