Oxidative dehydrogenation of isobutyric acid by heteropolycompounds: effect of alkali containing supports

Heteropolyacid catalysts such as H 3+n PV n Mo 12−n O 40 (n = 0, 1, 2, 3) and its alkali salts are active and selective in the oxidative dehydrogenation of isobutyric acid, but their stability under working conditions is still not reached. As it has been reported in literature [1, 2, 3] the thermal stability of H 3 PMo 12 O 40 is enhanced in the presence of large amounts of its alkali salt K 3 PMo 12 O 40 . Our trials [5] to improve heteropolyanion stability led us to support this compound on crystalline silica containing potassium. The obtained results were quite encouraging. Thus, alkali salts X 3 PMo 12 O 40 (X = K, Cs) and silica containing alkali ions were used as supports for the active phase H 4 PVMo 11 O 40 and the evolution of catalytic performances was studied