Oxidative Conversion of Methane of Natural Gas to Oxygen Containing Compounds

Abstract

The search of new compositions of catalysts on carriers on the base of heteropoly compounds of molybdenum for oxidative conversion of methane, the identification of optimal conditions for the partial oxidation of methane to formaldehyde, as well as study the surface properties of catalysts by complex methods and their relation to catalytic properties were the aim of work. Physico-chemical properties of bulk and supported heteropoly compounds were investigated by complex methods. The optimum composition of thermal stable catalyst over carrier on the base of molybdenum heteropoly compounds for process of methane oxidation into formaldehyde was developed. It has been shown that the water vapor has a positive influence on the yield and selectivity by formaldehyde. Probably, the catalyst does not change the structure at the production stage of formaldehyde from methane at the abovementioned temperatures; only the transition of Mo⁶⁺ into Mo⁵⁺ is observed. Re-oxidation of this catalyst by oxygen of gas-phase or by oxygen with water vapor leads to the disappearance of Mo⁵⁺ signals in EPR spectra and return of parameters specific to Keggin structure of HPA (773-873 K) (XRD, IRS, TPR).