SYNTHESIS, CHARACTERIZATION, AND CATALYTIC PROPERTIES OF ALPO4-40, COAPO-40, AND ZNAPO-40

The experimental conditions leading to the synthesis of pure and highl y crystalline AIPO(4)-40, CoAPO-40, and ZnAPO-40 have been optimized. Although the preparation of these phases is favored by the presence of TMA(+) in the synthesis gel, these ions have not been found incorpora ted in the final AFR structures. All materials have been characterized by powder XRD, t.g./d.s.c., SEM, EDX, C-13, Al-27, and P-31 solid-sta te n.m.r., diffuse reflectance u.v.-vis spectroscopy, FT i.r., and cat alytic tests using the m-xylene isomerization as a model: reaction. Th is multitechnique approach provides strong evidence for the framework incorporation of cobalt and zinc. The acid sites generated by the fram ework insertion of cobalt and zinc are stronger than those generated b y the incorporation of silicon. (C) Elsevier Science Inc. 1997.