Insertion of silicon into the crystal framework of a zeolite

Abstract

Silicon is inserted into the crystal lattice of zeolites containing defect sites by reaction with SiCl 4 in the presence of oxygen. It has been found that by initially dehydrating the starting zeolite and removing the hydroxyl groups existing in the crystal defect sites, the generation of HCl from the SiCl 4 reagent is avoided along with the undesirable aluminum hydrolysis reactions between the HCl thus-generated and the zeolite framework. The prior dehydration and dehydroxylation makes the presence of oxygen essential to the silicon insertion.