The selective oxidative activation of light alkanes.From supported vanadia to multicomponent bulk V-containing catalysts

摘要

V-containing materials have been proposed as active and selective catalysts in the selective oxidative transformation of C_2-C_4 alkanes to the corresponding olefins,oxygenates and nitriles.Although vanadium ions are generally assumed as the active sites in the oxidative activation of short chain alkanes,the coordination,the oxidation state and the environment of V atoms strongly influence both the catalytic activity and the nature of the reaction products.A comparative study on the catalytic behaviour of V-containing catalysts,i.e.metal vanadates,supported vanadium oxides,V-containing microporous/mesoporous materials and multicomponent bulk Mo-V-Te(Sb)-Nb mixed metal oxides,on the alkane oxidation is presented.The influence of the structure (including the V-coordination and V-environment) and the physico-chemical properties (especially redox and acid-base characteristics) of the catalysts on their behaviour in the selective oxidation of paraffins and alkenes is discussed.