Process for producing unsaturated aldehydes and unsaturated carboxylic acids

In a process for catalytically oxidizing t-butyl alcohol in the gas phase with molecular oxygen at a temperature of 200.degree. to 450.degree. C. to the corresponding aldehyde, and acid, the improvement comprising:

• oxidizing said t-butyl alcohol over a calcined catalyst consisting essentially of:
• Mo.sub.2 Sb.sub.b Bi.sub.c Fe.sub.d Ni.sub.e Co.sub.f Sn.sub.g X.sub.h Y.sub.i O.sub.j
• wherein X is at least one metal selected from the group consisting of potassium, rubidium, cesium and thallium, and Y is at least one metal selected from the group consisting of selenium, tellurium, gallium, vanadium, ruthenium, zinc, niobium, magnesium, chromium, manganese, cadmium and tantalum;
• wherein the subscripts a to J are the atomic ratios of each component and a is 12, b= 0.2 to 20, c= 0.2 to 12, d= 0.2 to 12, e= 0.2 to 12, f= 0 to 20, g= 0 to 20, h= 0.01 to 4, i= 0.01 to 4, and j is a value determined by the valencies of the elements in the catalyst, and when Y is at least one metal selected from the group consisting of chromium, manganese and cadmium, f is 0.