Improvement of the preparation method of ship-in-the-bottle type 12-molybdophosphoric acid encaged Y-type zeolite catalysts

In this work, efforts were made to improve the preparation method of ship-in-the-bottle type 12-molybdophosphoric acid (PMo12) encaged Y-type zeolite catalysts. First, the possibilities of modifying other popular heteropoly acid synthesis methods to prepare encaged catalysts were examined. It was found that only the conventional method, which uses MoO3 and H3PO4 for PMo12 synthesis, led to a significant amount of PMo12 encaging. Next, using this conventional method, the influences of temperature and solvent addition during synthesis on the amount of PMo12 encaging and the stability of the resulting encaged catalyst were investigated. It was found that by adjusting the reaction temperature, the stability of the resulting encaged catalyst could be enhanced to higher levels. Moreover, it was found that by adding t-butyl alcohol (TBA) to the solution used for catalyst synthesis, an active and stable encaged catalyst can be prepared even at low synthesis temperatures. (C) 2003 Elsevier B.V. All rights reserved.