Wacker oxidation of ethylene over vanadia nanotube supported Pd catalysts

The selective oxidation of olefins to aldehydes and ketones by O-2 using PdCl2/CuCl2 catalyst system in hydrochloric acid solution is known as Wacker process. Because of the advantages of heterogeneous catalytic systems there is great industrial interest in the development of solid Wacker catalyst. The present paper relates to the preparation and properties of novel Pd/vanadia nanotube catalysts and their activity in the Wacker oxidation of ethylene. The VOx nanotubes, having coil structure, were shown to be stabilized by interlayer cations. The as-synthesized VOx nanotubes had diameter of about 70-120 nm and contained exchangable interlayer alkylammonium (AA) cations. By ion exchange VO2+ and Cu2+ cationic forms were obtained. All three forms were tested as catalyst support. Palladium nanoparticles of 8-12 nm sizes were generated on the Surface of the VOx tubes. The best acetaldehyde selectivity was achieved with the Pd/AA-VOx catalyst. (C) 2012 Elsevier Ltd. All rights reserved.