Synthesis of bis-quaternary ammonium peroxotungstates (peroxomolybdates) and their catalytic activity in oxidation of alcohols by aqueous H2O2

Abstract

Three kinds of bis-quaternary ammonium salts of peroxotungstate and peroxomolybdate, such as PhCH₂N-(CH₂)₆NCH₂Ph[W(O₂)₄] ° 2H₂O, PhCH₂N(CH₂)₆NCH₂Ph[WO(O₂)₂(C₂O₄)] and PhCH₂N(CH₂)₆NCH₂Ph [MoO(O₂)₂(C₂O₄)], have been synthesized and characterized. Their catalytic activity in the oxidation of cyclohexanol and benzyl alcohol was investigated with only aqueous 30% hydrogen peroxide. The results show that the bis-quaternary ammonium peroxotungstates are excellent catalysts in the oxidation of benzyl alcohol and cyclohexanol under moderate conditions. However, the catalytic ability of bis-quaternary ammonium peroxomolybadates is relatively poor. The yields of benzyl acid, benzaldehyde, and cyclohexanone reached up to 93.0%, 93.6%, and 91.7%, respectively.

Keywords

peroxotungstate, peroxomolybadate, bis-quaternary phosphonium, hydrogen peroxide