Aluminum incorporation in mesoporous MCM-41 molecular sieves and their catalytic performance in acid-catalyzed reactions

Abstract

Mesoporous aluminosilicate molecular sieves, Al-containing MCM-41, with different Si/Al ratios were synthesized by four different methods: sol–gel, hydrothermal, template cation exchange and grafting. The catalysts prepared by sol–gel, grafting and template cation exchange methods are effective for the incorporation of large amounts of aluminum into the framework of MCM-41. The catalytic activities of the resulting Al-containing MCM-41 samples were tested in the cracking of cumene and the dehydration of 2-propanol, as model acid-catalyzed reactions, and then compared with the results obtained from microporous H-ZSM-5 and HY zeolites. The Al-containing MCM-41 catalysts prepared by different methods behaved differently in acting as acidic catalysts; the catalyst (having almost same Si/Al ratio) prepared by sol–gel method showed higher cracking activity, whereas that prepared by template cation exchange method showed higher dehydration activity. Moreover, these Al-containing MCM-41 catalysts are more catalytically active than microporous HY zeolite for cumene cracking and 2-propanol dehydration reactions.