Cyclohexane oxidation using transition metal-containing aluminophosphates (MAPO-VFI)

The preparation of Co-, Cr-, Fe-, Mn-, Ti-, and V-containing aluminophosphates (MAPO) with VFI structure is described. Physico-chemical techniques were used to characterize the solids synthesized. The MAPO-VFI were compared to AIPO-VFI impregnated with the various metals confirming the isomorphous substitution of Co, Cr, Fe, and Ti into the structure. V is coordinated to defect sites and Mn probably precipitated as oxide on the crystal surface. V- and CrAPO-VFI are active catalysts for the oxidation of cyclohexane with tert-butyl hydroperoxide producing cyclohexanone with some cyclohexanol and cyclohexene. CrAPO-VFI was recycled twice without significant loss of activity. On the other hand, VAPO-VFI showed significant metal leaching.