MORDENITE WITH LONG LIFE AND SELECTIVITY FOR METHANOL CONVERSION TO GASOLINE - MORDENITE MODIFIED BY BARIUM ION-EXCHANGE, DEALUMINATION AND CHEMICAL VAPOR-DEPOSITION OF SILICON METHOXIDE

In order to develop a long-life and selective mordenite catalyst for methanol conversion to gasoline, the physico-chemical properties of mordenite were modified by three methods: dealumination, barium ion exchange and chemical vapor deposition (CVD) of silicon methoxide. Catalyst life was improved significantly by controlling acid properties both by dealumination and barium exchange. Barium ion-exchanged dealuminated mordenite with low acid site density and weak acid site strength showed the longest life amongst the catalyst so far studied by the authors. On the other hand, in order to improve the selectivity, by suppression of the formation of heavy aromatics such as pentamethylbenzene, the pore-opening sizes of dealuminated mordenite and barium ion-exchanged dealuminated mordenite were modified by CVD of silicon methoxide. In dealuminated mordenite, activity was decreased rapidly by the CVD method. In the barium ion-exchanged dealuminated mordenite, however, the formation of heavy aromatics with more than 11 carbon atoms was almost inhibited by the CVD method, while the lifetime was unchanged. © 1990.