Methyl bromide synthesis via oxidative bromination of methane

Abstract

The thermodynamic stability of methane is a critical factor for methane utilization. Oxidative bromination of methane (OBM) is one of the reaction pathways to transform methane into more reactive reactant, methyl bromide (CH3Br), which can be used for the productions of higher hydrocarbons and/or other compounds. In the current study, methane was brominated with HBr/H2O, with the flow of oxygen and nitrogen in a fixed-bed continuous-flow reactor at atmospheric pressure. The effect of various parameters including support materials, w t% Rh/SiO2 catalyst, reaction temperature, and %O2 were investigated. Before and after the reaction, the catalysts were also characterized by several techniques—BET, XRD, TPR, H2 Chemisorption, and SEM. The results shows that under the same conditions (20 ml/min of CH4, 5 ml/min of O2, 5 ml/min of N2, 6.5 ml/h of 48 w t% HBr/H2O), high selectivity of CH3Br (100%) could be achieved at reaction temperature of 400 ℃, while at higher temperature partial oxidation of methane to synthesis gas was instead dominant. Moreover, when adding Rh/SiO2 catalyst, the methane conversion increased while the high selectivity to methyl bromide was preferable.