Journal of Molecular Catalysis A-Chemical, Vol.380, 90-93, 2013
Decarbonylation of water insoluble carboxaldehydes in aqueous microemulsions by some sol-gel entrapped catalysts
In the course of our attempts to replace harmful solvents in organic processes by environmentally favored media, we investigated the use of aqueous microemulsions for catalytic decarbonylation of different kinds of aldehydes. The aldehydes were solubilized in the microemulsions with the aid of the cationic surfactant, cetyltrimethylammonium bromide. The aldehydes were transferred into CO-free products by sal gel entrapped catalysts. The best results were obtained in the presence of nanoparticles of Pd(0). The heterogenized catalyst could usually be recycled 7-8 times without loss of catalytic activity. At relatively low temperatures (140 degrees C) the decarbonylation proceeds stepwise. Initially a mixture of saturated and unsaturated products is formed. At 180 degrees C however, fast hydrogenation of the unsaturated compounds takes place. These investigations may be regarded as model studies for the conversion of biomass derived intermediates to fuels and chemicals. (C) 2013 Elsevier B.V. All rights reserved.
Keywords:Aldehyde decarbonylation;Heterogeneous catalysis;Microemulsion;Palladium nanoparticles;Sustainable chemistry