Low-temperature synthesis of dimethyl ether from syngas over CuZno/HZSM-5 catalysts

Abstract

A new dimethyl ether synthesis route from syngas at a low temperature (170℃) has been developed for the first time by the combination of a conventional DME synthesis catalyst (CuZnO/HZSM-5 catalyst) with methanol as a catalytic solvent. The addition of methanol to the reaction system is the key to the success of DME synthesis at this temperature. Indeed, CO conversion of 30.9% and DME selectivity of 72.5% were achieved at 170℃, 4.0 MPa and over a 1 g of catalyst (ratio of CuZnO/H-ZSM-5 = 2:1), when 40 mL of methanol was used as a catalytic solvent. Importantly, no other by-products including methanol and hydrocarbons were observed in the DME product attained, suggesting no significant subsequent purification stages. This process potentially provides a high purity of DME with less energy consumption, and so offers an opportunity of economically viable future sustainable production of DME.