| abstract |
An unsaturated aldehyde having three to four carbon atoms is prepared by reacting the corresponding olefin with molecular oxygen in the vapor phase at a temperature of from 350 DEG to 520 DEG C in the presence of a metal oxide catalyst comprising the metallic components: (a) molybdenum; (b) at least one metal selected from the group consisting of niobium and tantalum; and (c) at least one metal selected from the group consisting of tellurium, bismuth, cobalt, tungsten, indium, and titanium. |