Formic Acid Production Via Methane Peroxide Oxidation Over Oxalic Acid Activated Fe-MFI Catalysts

Abstract

The process of synthesis of formic acid via partial peroxide oxidation of methane over Fe-MFI zeolites, as well as the influence of the catalyst activation by oxalic acid on the process parameters (conversion and selectivity) was studied. XRD, ICP-OES, SEM, UV–Vis DR, ESR, NH3-TPD, 27Al MAS NMR, N2 adsorption techniques were used for the catalyst characterization. The observed increase in TOF, selectivity to formic acid and efficiency of H2O2 utilization upon the catalyst activation with oxalic acid was accounted for by the formation of oligomeric oxo-clusters of Fe-ions and by an increase in the total acidity of the catalysts. The process of oxidation of main intermediates of the reaction, such as methanol and formic acid, was studied in the presence and in the absence of methane that allowed the mechanism of methane oxidation to formic acid to be suggested.