Effect of heat treatment on the catalytic activity and selectivity of action of high-silica zeolites in transformations of xylenes

In studying the isomerization and disproportionation of xylenes, the temperature range of the formation and destruction of active centers in zeolites of the pentasil and mordenite type was established. Active centers resistant to heat treatment at 973–1073 K are present on the surface of zeolites prepared by direct synthesis.