Insights into the influence of various impurities on the stability of a Cu/SiO2 catalyst for the hydrogenation of dimethyl oxalate to ethylene glycol

Abstract

The impact of common impurities possibly involved in the industrial production process for the hydrogenation of dimethyl oxalate to ethylene glycol on the stability of a commercial Cu/SiO₂ catalyst is investigated. The presence of 1 wt% dimethyl carbonate or ethylene carbonate impurities in the pure dimethyl oxalate feedstock causes the apparent deactivation of the Cu/SiO₂ catalyst, and the deactivation rate depends on the amount of carbonaceous deposit, especially soft carbon, on the catalyst. Introducing 0.1 wt% NH₄Cl to the catalyst leads to more severe deactivation in the very initial stage, which originates from silicon loss and rapid Cu agglomeration. Moreover, the final extent of catalyst deactivation correlates with the degree of agglomeration of Cu nanoparticles under different conditions. This work provides insights into the rarely discussed issue of the influence of impurities on industrial applications and enhances comprehension of the improvement in the stability of Cu/SiO₂-based catalysts.