Process for preparing acrylonitrile

A process for preparing acrylonitrile which comprises reacting at an elevated temperature in the vapor phase propylene, oxygen and ammonia over a catalyst consisting essentially of a compound defined by the formula:

• USb.sub.3-x A.sub.x O.sub.9-10,
• wherein A is a Group IV B element, x is the number about 0.25 to about 1.50, said catalyst having been prepared by heating a mixture containing (1) oxides or uranium, antimony and an element from Group IV B of the Periodic Table or (2) compounds of said elements that will decompose or be converted to said oxides during said heating, wherein the atomic ratio of antimony to uranium is about 1.35:1 to about 2.75:1, the atomic ratio of the Group IV B element to uranium is about 0.25:1 to about 1.65:1 and the atomic ratio of the sum of antimony and Group IV B element to uranium is about 3.5:1 to about 2.5:1, at a temperature of at least about 850.degree. C. for about 15 minutes to about 24 hours.