Study on selective oxidation of isobutylene catalyzed by heteropoly compound membrane

A catalytic membrane, supported on porous titanium plate, composed of heter opoly compound (HxCu1.2PAs0.6Mo12Oy, abbreviated to HCPAMO) and Sb2O4 with oxygen spillover effect was prepared. Selective oxidation of isobutylene wa s carried out in a catalytic membrane reactor. The results showed that the HCPAMO-Sb2O4 membrane has high catalytic activity. Under the optimum reacti on conditions, i. e. n (i-C-4(=)): n(O-2): n(H2O) = 1.0:2.3:5.0, q(V)(feed) = 1.158 L/h, theta = 360 degreesC, the yield of methacrylic acid is 26.3%, the yield of methacrolein is 22.4%, and the total yield of liquid products (methacrylic acid, methacrolein, acetic acid and acetone) reaches 67.4%. I t is suggested that the Sb2O4 increases the transferring velocity of the ox ygen-species during the redox process owing to its oxygen-spillover effect.