Preparation of vanadium phosphate catalyst precursors for the selective oxidation of butane using α,ω-alkanediols

Vanadium phosphate catalyst precursors were prepared from V2O5 and H3PO4 or VOPO4·2H2O using α,ω-alkanediols (1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol) as both the reducing agent and the solvent. A series of layered VOHPO4·HO(CH2)nOH (n = 4–6) materials intercalated with α,ω-alkanediols were obtained. The performance for butane oxidation of the final catalysts formed via the in situ transformation of the VOHPO4·HO(CH2)nOH precursors under reaction conditions is described. The final catalysts derived from the alkanediol intercalated materials were found to exhibit relatively low selectivities to maleic anhydride and comprised of VV (VOPO4) phases with an amorphous VIV phase. However, when a crystalline (VIVO)2P2O7 phase is present, with small amounts of VV phases, as with materials prepared with 1,4-butanediol, the specific and intrinsic catalytic activity are higher.