Patent ID: 6858561

Claim:
The method of preparing a vanadium phosphorus mixed oxide catalyst which comprises forming an admixture of a +5 vanadium compound and an anhydrous phosphoric acid in an organic alcohol solvent, said admixture optionally also comprised of promoter compounds, heating the admixture to reflux in less than 3 hours, refluxing the admixture for 0.5-24 hours, cooling the resulting refluxed admixture without removal of solvent by distillation, recovering catalyst precursor particles having the formula (VO)HPO 4 aH 2 OM m P p O y wherein M is at least one promoter element selected from the group consisting of elements form Group IA, IB, IIA, IIB, IIIA, IIIB, IVA, IVB, VA, VB, VIA, VIB, and VIIIA of the Periodic Table of Elements, and mixtures thereof, a is a number of at least about 0.3, m is a number of from about 0 to about 0.3, and y corresponds to the amount of oxygen necessary to satisfy the valence requirements of all elements present from the cooled admixture by filtration, drying and calcining the recovered particles without solvent washing for use as catalyst.