Oxidation of methane to methanol on the surface of FeZSM-5 zeolite

• Published in: Journal of catalysis 2013-04, Vol.300, p.47-54
• Main Authors: Starokon, Eugeny V., Parfenov, Mikhail V., Arzumanov, Sergey S., Pirutko, Larisa V., Stepanov, Alexander G., Panov, Gennady I.
• Format: Article
• Language: English
• Subjects: 13C MAS NMR; acetaldehyde; ambient temperature; Catalysis; desorption; FeZSM-5; gases; hydrogen; IR spectroscopy; Methane; Methane oxidation; Methanol; Methanol from methane; Nitrous oxide; Oxidation; oxygen; Product extraction; Quasicatalytic reaction mode; Spillover; zeolites; α-Oxygen
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2012.12.030

Methane oxidation by N2O was studied at 160°C on the FeZSM-5 surface with increased concentration of α-sites (100μmol/g). The reaction was shown to lead directly to methanol. Spillover of methanol from α-sites provides a “quasicatalytic” mode of the reaction with TON>3. [Display omitted] ► Methane oxidation by N2O on FeZSM-5 α-sites at 160°C leads directly to methanol. ► Methanol spillovers from α-sites providing “quasicatalytic” mode of reaction (TON>3). ► A part of methanol is converted to DME and non-extractable products. In our previous work using FeZSM-5 zeolite with increased concentration of α-sites (100μmol/g), the oxidation of methane by α-oxygen predeposited from nitrous oxide was studied at room temperature. The reaction proceeded by hydrogen abstraction mechanism yielding methoxy and hydroxy groups bound to α-sites. The present work conducted with the same zeolite is devoted to methane oxidation by N2O in the process of α-oxygen deposition at 160°С. Under these conditions, the reaction was shown to proceed at a stoichiometric ratio СН4:N2O=1:1 yielding directly methanol. Spillover of methanol from α-sites liberates them for further events of α-oxygen deposition, thus converting the reaction to a “quasicatalytic” mode that runs up to turnover number exceeding 3 with no product desorption into the gas phase. A part of methanol is converted to dimethyl ether, traces of acetaldehyde, and some amount of non-extractable products. Mechanism of the reaction is discussed.