Dual catalyst bed system was introduced into the conversion of methane in one reactor simultaneously to ethylene and syngas with appropriate concentrations, which could be used for further production of propanal via hydroformylation. To avoid the over consumption of O-2 on the first catalyst bed, the moderately active catalyst Co/gamma Al2O3 for methane partial oxidation was employed, followed by Na2WO4/Mn/SiO2 catalyst, which was one of the most effective catalysts for the oxidative coupling of methane. The distribution of products could be tuned by controlling the relative dosages of the two catalysts and the reaction conditions. A mixture with the desired composition of CO/H-2/C2H4 = 1.1/1/1.2 was achieved, with the total yield of CO and C2H4 Of about 18.5%, under the following optimized conditions: F = 150 cm(3)/min, CH4/O-2 = 3, M-1:M-2 = 0.01 g:0.16 g (1: Co/gamma-Al2O3; 2: Na2WO4/Mn/SiO2). (C) 2007 American Institute of Chemical Engineers.