STRUCTURAL EFFECTS ON PROPANE MILD OXIDATION FROM COMPARATIVE PERFORMANCES OF MOLYBDENUM AND VANADIUM PHOSPHATE MODEL CATALYSTS

Thirty well-defined catalysts AMPO (A alkaline, alkaline earth metal, Cd, Pb, Ag; M = Mo, V) with different compositions and structures were tested for propane mild oxidation in the same conditions (C3H8/O-2/N- 2 = 60/20/20, W/F = 3.5 g h L-1 at 450 degrees C). Comparisons of thei r catalytic performances allowed us to conclude that if sodium should be left out from catalytic formulations, cadmium and silver are quite promising cations. The best performances are obtained with a lattice i nvolving polynuclear limited size units (two, three, or four transitio n metal atoms). This configuration makes easier electronic exchanges o ccurring during the reaction.