Nanosize Gold Promoted Vanadium Oxide Catalysts for Ammoxidation of 2-Methylpyrazine to 2-Cyanopyrazine

Ammoxidation of 2-methylpyrazine to 2-cyanopyrazine has been carried out using nano sized gold promoted vanadia catalysts in the temperature range from 360 to 400 degrees C at atmospheric pressure. Three different types of metal oxides [e.g. CaO, Al2O3 and TiO2 (anatase)] with varying surface areas were used as catalyst supports. The catalysts were prepared by three-step impregnation method and characterised by various techniques. Characterisation results showed the formation of nano-sized gold particles in the range from 2 to 5 nm. However, their size and morphology strongly depends upon the nature of support applied. Catalytic results revealed that Au is an efficient promoter for vanadia catalysts in improving the yield of the desired product, 2-cyanopyrazine, due to synergistic effect between the Au and VOx species. Among all, V2O5-Au/TiO2 exhibited the best performance giving over 75 % conversion of 2-methylpyrazine and close to 50 % yield of CP.