Production of dimethyl carbonate by gas-phase oxidative carbonylation of methanol over Cu/Y zeolite: Mechanism and kinetics

Dimethyl carbonate (DMC) has become into an appealing fuel additive for reducing the formation of pollutants during combustion and, together with the post-combustion treatment, allowing to fulfill the most stringent environmental regulations. Although the production of this chemical is still an open issue, the oxidative carbonylation of methanol catalyzed by solids and with reactants and products in the gas phase has been proposed to replace the homogeneous commercial process (CuCl in aqueous phase). In this work, we propose the use of a Cu/Y zeolite (prepared by solid-state ion exchange with copper (I) chloride) as alternative catalyst for this purpose, optimizing the reaction conditions and proposing a rigorous kinetic model for this reaction. For accomplishing this aim, gas phase reaction was performed in a continuous fixed-bed reactor. Temperature (100-200 C) played a critical role in product distribution, DMC being the main product at 120 C. The influence of different reactant (CH3OH/CO/O-2) concentrations on reaction rate and product distribution was determined at 120 C. The experimental data have been successfully fitted to a kinetic model, derived from the mechanism of the reaction.