Oxidative Coupling of Methane on MgO-MgSO4 Catalysts in the Presence and Absence of Carbon Tetrachloride

Article abstract of DOI:10.1246/bcsj.69.235

The effect of carbon tetrachloride (CCl₄) on the oxidative coupling of methane on binary catalysts containing MgO and MgSO₄ was studied at 1048 K. With no CCl₄ in the feedstream the conversion of methane increased with increasing content of MgO in the binary catalyst, but was even further enhanced by introducing a small partial pressure of CCl₄. The selectivity to ethylene increased upon the addition of CCl₄, but was not dependent on either the concentration of CCl₄ in the feedstream or the relative amounts of the two components in the catalyst. X-Ray photoelectron spectroscopic analyses of the used catalysts showed that the sulfate is partially transformed into the oxide as well as the formation of Cl species in the near-surface region of the catalysts during the methane conversion process. The addition of CCl₄ enhances the conversion of sulfate to oxide. The oxide formed by the decomposition of the sulfate and the chlorine species plays different roles in improving the catalytic activities by introducing CCl₄.