Vanadium catalysts for oxidation of alcohols

Abstract

In this thesis, some vanadium containing oxides and vanadium complexes were prepared. They are n-Bu[subscript 4]NVO[subscript 3] (A), [NBu[subscript 4]][V(cat)[subscript 3]]) (B), V-L-valine (C), V-EDTA (D), V-PCA (E), (VO)[subscript 2]P[subscript 2]O[subscript 7] (F), VO(PO[subscript 4])(H[subscript 2]O)[subscript 2] (G), VO(HPO[subscript 4])(H[subscript 2]O)[subscript 4] (H)). These were characterized by XRD, FT-IR, UV-Vis and melting point. They were used to catalyze the oxidation of alcohols at 70 ํC, 24 h using alcohol/oxidant mole ratio = 2, alcohol/catalyst mole ratio = 60. The reaction products were analyzed by GC technique. The experimental results show that all vanadium catalysts catalyze the oxidation of alcohols to aldehyde or ketone with high yield. In the case of benzyl alcohol oxidation, the product depended on the solvent used, in toluene, benzaldehyde was obtained. But in acetonitrile, the reaction showed selectivity to benzoic acid (70% selectivity). The oxidation of 1-phenylethanol yielded acetophenone while cyclohexanol gave cyclohexanone . The reactivity of alcohol demonstrated by all the catalysts is: benzyl alcohol > 1- phenylethanol > cyclohexanol. The reactivity order of the catalysts found in this work revealed that the vanadium complexes containing chelating ligand are better than the vanadium containing oxide catalysts, and the reactivity is comparable to the commercial V[subscript 2]O[subscript 5].