CONVERSION OF METHANE TO STYRENE OVER THE MIXED CATALYST LA2O3+MOO3 HZSM-5/

The catalytic transformation of CH4 in the presence of O-2 over La2O3, MoO3/HZSM-5 and the mixed catalyst, La2O3 + MoO3/HZSM-5, has been inv estigated and compared. MoO3/HZSM-5, which is known as an active catal yst for the dehydrogenation and aromatization of methane in the absenc e of oxygen, shows very low selectivity towards the formation of aroma tic compounds in the presence of oxygen. However, the combination of M oO3/HZSM-5 with La2O3 which is a very active catalyst for the producti on of ethane, ethylene, CH3 and CH2 species under the reaction conditi ons, provides a catalyst, La2O3 + MoO3/HZSM-5, that is rather active f or transformation of methane to styrene. At 1023 K, a methane conversi on of 18.3% and styrene selectivity of 10.8% are obtained from a CH4/O -2 (6/1 mole ratio) reactant gas in a feed flow rate of 3500 ml/h. Nor mal deuterium isotope effects on both the methane conversion reaction and the styrene formation over the La2O3 + MoO3/HZSM-5 catalyst have b een observed in the reaction.