Selective oxidation of alcohols to aldehydes using inorganic–organic hybrid catalyst based on zinc substituted polyoxometalate and ionic liquid

Abstract

Various organic–inorganic hybrid compounds, [bmim] _x [PW₁₁MO₃₉] · 3H₂O {(bmim: 1-n-butyl-3-methylimidazolium) and [M = V(IV), Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II)]}, were prepared and characterized by elemental analysis, UV-Vis, FT-IR, and TGA. The synthesized hybrid compounds were used as catalysts in oxidation of various alcohols with hydrogen peroxide in acetonitrile. The effect of the transition metal on the catalytic activity was in the order, Zn > Fe > Ni > Cr > Co > V > Mn > Cu. In this catalytic system, the effects of other parameters such as the type of solvent, amount of oxidant and catalyst, and the temperature were also investigated. [bmim]₅[PW₁₁ZnO₃₉] · 3H₂O was reused several times without loss of catalytic activity.

Keywords:

• Hybrid catalyst
• Polyoxometalate
• Ionic liquid
• Oxidation
• Alcohol
• Aldehyde

Acknowledgments

The support of this work by Center of Excellence of Chemistry of University of Isfahan (CECUI) is acknowledged.