ADSORPTION OF PYRIDINE ON DEALUMINATED ZEOLITE HY

摘要

Infrared spectra showed that over 80/100 of aluminum atoms on the surface of zeolite HY were extracted by a exposure of SiCl_4 vapor at elevated temperatures. The dealuminaiton of the HY surface resulted in an appreciable change in its acidic properties. Infrared spectra of adsorbed pyridine indicated the formation of various kinds of Lewis acid sites on the delauminated HY surfaces. Although the total number of the surface Bronsted acid site decreased in the SiCl_4-induced dealumination process, the nature of these remaining Bronsted acid sites was unchanged spectroscopically.