Synthesis of formaldehyde from dimethyl ether on alumina-supported molybdenum oxide catalyst

The selective oxidation of DME to formaldehyde over alumina-supported MoOx catalyst (prepared by dry impregnation) is studied in this work. The activity and stability of the catalyst were evaluated in a fixed-bed continuous reactor at different temperatures and reactant concentrations. The influence of the main operating conditions, (DME, O-2, CO2 and CO feed concentrations; reaction temperature) on reaction rate and product selectivity was experimentally determined. Thus, DME conversion decreases on increasing DME feed concentration and increases on increasing 02 feed concentration. Formaldehyde selectivity remained almost unaffected. A reaction mechanism, based on a Mars-van-Krevelen redox cycle representing DME oxidation to formaldehyde was used as a basis to develop a kinetic model for the reaction. The resulting simplified model suggests power law dependences for the reaction rate of 0.2 for the O-2 and 0.5 for the DME. (C) 2016 Elsevier B.V. All rights reserved.