A new layered vanadyl (IV) phosphate with an expanded interlayer

At high H3PO4: V2O5 ratios (>4:1), the reaction of V2O5 with H3PO4: EtOH at reflux for extended times gives rise to a material of formulation (VOHPO4)2·2.5H2O·EtOH. This material is thermally stable, and has a Stage I layered structure with a distance of 13.58 Å between the vanadyl(IV)-phosphate containing planes. Spectroscopic evidence suggests that the EtOH molecule acts as a pillar holding these layers apart and that the stability is due to coordination of the ethanol to in-layer V(IV) atoms. Thermal decomposition of the material gives materials different than those given by the hemihydrate analogue VO(HPO4)20.5H2O. Such decomposition products may - in part at least - be responsible for many of the irreproducible results found during the preparation of precursors for the V-P-O catalysts adopted in the butane maleic anhydride conversion. © 1987.