Formation of Acrylaldehyde by Vapor-Phase Aldol Condensation II. Phosphate Catalysts

Article abstract of DOI:10.1246/bcsj.64.1346

Vapor-phase aldol condensation of formaldehyde with acetaldehyde to form acrylaldehyde was studied with various oxide and phosphate catalysts using 35percent formalin as the source of formaldehyde.Almost all of the tested oxides exhibited a certain activity as the catalysts.Acidic oxides, such as MoO3 and WO3 showed a relatively high selectivity to acrylaldehyde, though the activities were low.V2O5 and amphoteric oxides exhibited a much higher activity, but they promoted also the formation of CO2 and methanol.The catalytic performance was improved, to a certain extent, by combination of an acidic oxide with an amphoteric oxide.Further, the combination of phosphorus with V2O5 or an amphoteric oxide induced a large increase in the selectivity to acrylaldehyde.A good performance was obtained with the Ni-P, Mn-P, Fe-P, and V-P systems.The yield of acrylaldehyde reached 86 molpercent on the AcH basis with a very slow formation of CO2 and methanol.