Selective solvent free oxidation of aldehydes to carboxylic acids over anchored 12-tungstophosphoric acid using different oxidants

The catalysts comprising 12-tungstophosphoric acid anchored to different mesoporous (mobile composition of matter - MCM-41 and MCM-48) and metal oxide (zirconia) supports were synthesized and characterized. Their catalytic activities were evaluated for the solvent free oxidation of aldehydes to carboxylic acids using molecular oxygen and hydrogen peroxide. The influence of various reaction parameters were studied. The effect of oxidants as well as supports were thoroughly investigated. Based on the above studies, 12-tungstophosphoric acid anchored to mesoporous molecular sieves MCM-48 was found to be the best catalyst. All the catalysts were easily regenerated and recycled. Further, the catalytic activity for oxidation of range of aldehyde substituents with different oxidants was also determined in order to ascertain the viability of the best catalyst.