IR-SPECTRA OF CATALYSTS AND ADSORBED MOLECULES .39. ACID AND CATALYTIC PROPERTIES OF PENTASILS MODIFIED WITH PLATINUM, CHROMIUM, AND ZINC

It was shown that when platinum is incorporated in pentasil (HZSM), the concentration of L sites increases by approximately 2 times With no change in the number of B sites; in Pt-Cr-containing catalysts, the concentration of L sites passes through a maximum with a 0.72% concentration of Cr, and the number of OH groups and B sites decreases. The concentration of B sites decreases and the concentration of L sites increases in samples simultaneously promoted with Pt, Cr, and Zn. In conditions of aromatization of lower alkanes on Pt-Cr-containing catalysts, the concentration of OH groups and B sites decreases, while the concentration of L sites increases. Incorporation of platinum in HZSM increases the aromatizing activity with respect to methane, and additional incorporation of chromium and zinc increases the yield of aromatic hydrocarbons from ethane and propane also.