Catalytic Oxidation of Oleic Acid in Supercritical Carbon Dioxide Media with Molecular Oxygen

Oxidation of oleic acid was performed over various ordered porous catalysts containing transition metal in supercritical carbon dioxide (scCO₂) media with molecular oxygen. Oleic acid was completely decomposed into mono- and dicarboxylic acids over porous catalysts, viz., mesoporous molecular sieves (CrMCM-41, MnMCM-41, CoMCM-41) and microporous molecular sieves (CrAPO-5, CoMFI, MnMFI) using scCO₂ at 353 K for 8 h. Among the different catalysts studied, microporous and mesoporous catalysts containing chromium, in presence of scCO₂ showed high distribution of azelaic and pelargonic acids as compared to their analogs containing cobalt or manganese. The presence of scCO₂ medium with the catalysts increased the distribution of azelaic and pelargonic acids. The effect of CO₂ pressure, reaction temperature and reaction time on oxidation of oleic acid over CrMCM-41 was also investigated. Additionally it is noticed that the catalyst can be recycled with negligible loss of catalytic activity.