Conjugation effects in ethane oxidation under the conditions of oxidative coupling of methane

Abstract

Ethane conversion under the conditions of oxidative coupling of methane (OCM) has been investigated. In an empty reactor above 800°C, ethane oxidation occurs at a higher rate, and its main product is carbon monoxide. In the presence of NaWMn/SiO2 catalyst the rate of ethane oxidation noticeably decreases, and ethylene becomes the main product of the reaction. Thus, it is demonstrated that the catalyst, on one hand, is an effective inhibitor of unselective gas phase oxidation processes, and on the other hand, it substantially changes the hydrocarbon conversion routes. The complex kinetic conjugation during ethane oxidation in the presence of an excess of methane in the reaction mixture is observed. In the case of homogeneous ethane oxidation, methane acts as the gas-phase oxidation inhibitor, presumably by reducing chain reactions contribution to the overall reaction rate. On the contrary, during the oxidation of a methane-ethane mixture over NaWMn/SiO2 catalyst, a strong mutual effect of the hydrocarbon components on the rate and direction of their transformation is observed.

Keywords

• oxidative coupling of methane, с₁-с₂ hydrocarbon oxidation, kinetic, heterogeneous-homogeneous processes, conjugation effects.