The reaction mechanism of ethane and ethene oxidation was studied under the OCM reaction conditions over MnxOy-Na2WO4/SiO2. The consecutive reaction of C-2 components is observed to be the main route to the formation of COX under the applied reaction conditions here. The homogeneous or heterogeneous nature of these unselective reactions was investigated in more details. For this purpose, the temperature programmed surface reaction (TPSR) technique was applied. The results of these experiments indicate that the consecutive reaction of ethane is mainly occurring in the gas phase of the reactor. This point was confirmed when the activation energy of ethane both, in the presence of the catalyst and silicon carbide, as the inert surface, was shown to be at the same level. The concentration profile of the effluent obtained by simulating the reaction of C-2 components using the Dooley mechanism in ChemkinPro was also in good agreement with this proposal. The reason for the low influence of the catalyst on conversion of ethane was ascribed to the film diffusion limitation that is occurring under the OCM reaction conditions applied in these studies. Finally, a set of experiments were performed with (CH4)-C-13 to study the effect of methane on the consecutive reaction of ethane in the OCM reactor. [GRAPHICS] .