Insights into the influence of various impurities on the stability of 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. Involving 1 wt.% dimethyl carbonate or ethylene carbonate impurities in the pure dimethyl oxalate feedstock causes an apparent deactivation of the Cu/SiO₂ catalyst, and the deactivation rate depends on the amount of carbonaceous deposit, especially soft carbon on the catalyst. While introducing 0.1 wt.% NH₄Cl in the catalyst leads to more severe deactivation at the very initial stage, which originates from silicon loss and the changed active surface Cu⁺/Cu⁰ ratio during the reaction. Moreover, the final deactivation extent of the catalyst corresponds to the agglomeration degree of Cu nanoparticles among different situations. This work provides insights into the rarely discussed issue of impurity influence in the industrial application and enhances the comprehension about the improvement of stability for Cu/SiO₂-based catalysts.