SYNTHESIS, CHARACTERIZATION AND CATALYTIC PROPERTIES OF MICROPOROUS MGVAPO-5

Vanadium- and magnesium-containing aluminophosphates with AFI structur e (MgVAPO-5) have been prepared by hydrothermal synthesis using trieth ylamine as template. XRD patterns of AFI structure were observed on bo th as-synthesized and calcined materials, although their crystalliniti es depend on the preparation conditions. FTIR of pyridine adsorbed and TPD of NH, indicate the presence of acid sites, related to the incorp oration of Mg2+ cations into the framework of AFI structure. However, EDX and SEM results indicate a different incorporation of vanadium and magnesium depending on the crystal size. These results indicate some heterogeneity of Mg- and/or V-containing materials. MgVAPO-5 catalysts are active and selective in the oxidative dehydrogenation of ethane. Isolated vanadium species are the active sites while the selectivity t o ethene is also related to the presence of acid sites.