Promotive Effect of Hydrogen Sulfide on the Catalytic Activities of Metal Ions Exchanged Y Zeolites for Cumene Cracking

Abstract

For cumene cracking, the catalytic activity of zeolite, exchanged with various metal ions, MeY (Me=Cd²⁺, Cu", Ni", Co", Ag+, and Zn²⁺), was enhanced by the pretreatment with hydrogen sulfide. An increase in catalytic activity was dependent on the affinity of metal ions in MeY toward hydrogen sulfide. The IR spectra of CdY treated with hydrogen sulfide indicated the formation of new hydroxyl groups on the surface. An increase in BrOnsted acidity of CdY was also observed after the pretreatment with hydrogen sulfide in the IR spectra of chemisorbed pyridine on CdY. Thus, it was considered that an increase in catalytic activity of MeY by the pretreatment with hydrogen sulfide was attributed to the formation of new acidic hydroxyl groups, i. e., BrOnsted acid sites, in terms of irreversibly adsorbed hydrogen sulfide on metal ions in MeY.