Process for the manufacture of unsaturated aldehydes and acids from the corresponding olefins

A process for the oxidation of propylene and isobutylene to form the corresponding unsaturated aldehydes and unsaturated acids comprising contacting in the vapor phase at a temperature within the range of from about 250.degree. to about 600.degree.C. a mixture of a molecular oxygen-containing gas and either propylene or isobutylene, or mixtures thereof, in a molar ratio of oxygen to olefin within the range from about 0.5 to 10, in the presence of a promoted, reduced, antimony oxide-molybdenum oxide-containing catalyst wherein the catalyst is prepared by combining the following components in any order:

• a. an aqueous slurry of molybdenum trioxide;
• b. a reducing agent selected from the group consisting of finely divided metal, sulfur, sulfur dioxide, hydrogen sulfide, hydrazine hydrate, ammonia, hydroxylamine and an organic reducing agent capable of reducing at least some of the molybdenum to a valence state below +6 in a ratio of from about 0.0001 to 0.2 moles of the reducing agent per mole of molybdenum;
• c. antimony oxide in a ratio of from about 0.1 to 9 moles of antimony oxide per mole of molybdenum;
• and
• d. at least one promoter element in the form of a non-oxidizing compound selected from the group consisting of tellurium, tungsten, titanium, manganese, nickel, iron, copper, lead, rhenium, bismuth, tin, uranium, chromium, phosphorus and boron, said promoter element being added in a ratio of from about 0.0001 to 1.0 moles of promoter element per mole of molybdenum.