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

At high H/sub 3/PO/sub 4/ : V/sub 2/O/sub 5/ ratios (>4:1), the reaction of V/sub 2/O/sub 5/ with H/sub 3/PO/sub 4/ : EtOH at reflux for extended times gives rise to a material of formulation (VOHPO/sub 4/)/sub 2/ . 2.5H/sub 2/O . EtOH. This material is thermally stable, and has a Stage I layered structure with a distance of 13.58 A 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(HPO/sub 4/)/sub 2/ . 0.5H/sub 2/O. 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