Selective ammoximation of ketones and aldehydes catalyzed by a trivanadium-substituted polyoxometalate with H2O2 and ammonia

The ammoximation of different ketones and aldehydes to their corresponding oximes catalyzed by K6[PW9V3O40]·4H2O was carried out with hydrogen peroxide and ammonia in isopropanol at room temperature. High yields of oximes were obtained in this catalytic system. This catalytic system was proved to be heterogeneous by the ammoximation activity of removal of catalyst and the elemental analysis of the filtrate after reaction. A possible procedure for the ammoximation catalyzed by K6[PW9V3O40]·4H2O with H2O2 and NH3·H2O was proposed. The fresh and used catalysts were characterized by IR and 31P MAS NMR, which revealed the good stability of the catalyst.

Graphic abstractA tri-vanadium-substituted polyoxometalate K6PW9V3O40·4H2O, was used to catalyze the ammoximation of different ketones and aldehydes to their corresponding oximes in the presence of hydrogen peroxide and ammonia with high yield and selectivity.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A vanadium-substituted polyoxometalate K6PW9V3O40·4H2O was prepared. ► It efficiently catalyzed ammoximation of ketones and aldehydes using H2O2 and NH3·H2O. ► High yields of oximes were obtained at room temperature. ► This catalyst proved to be heterogeneous in isopropanol and was recyclable.