Analysis of the catalytic effects of silver and copper in the hydrogenation of dimethyl oxalate from a product perspective.

As we advocate green chemistry, more and more environmental problems have been concerned. Considering the conditions of scarcity of oil and plenty of coal, we need to find out a feasible and efficient route in coal chemical industry rather than oil. For instance, many studies have pointed out that dimethyl oxalate produced by the gas-phase CO coupling reaction can be selectively hydrogenated to methyl glycolate (MG), deeply hydrogenated to ethylene glycol (EG) and ethanol (EtOH). The reviews that currently exist mainly focus on the structural design of catalysts and lack a systematic classification of catalysts along the lines of reaction pathways. This work provides readers with a new perspective by focusing on reaction pathways. Silver-based catalysts are the best catalysts for catalyzing the generation of MG from DMO due to their moderate activity, while copper-based catalysts are more inclined to generate EG or EtOH due to their higher catalytic activity. Secondly, this article also discusses several factors that affect product selectivity, such as temperature (MG: 180–200 ℃, EG: 200–230 ℃, EtOH: 230–280 ℃), element doping (Au, Ni, B, etc.), supports (SiO 2 , activated carbon, TiO 2 , ZrO 2 , etc.), etc. In addition, this article proposes for the first time a discussion on the active sites of silver-based catalysts in the hydrogenation of dimethyl oxalate. [Display omitted] • Summarizing Ag-based catalysts applied in dimethyl oxalate hydrogenation for the first time. • Explanation of the controversial issue of the adsorption strength of Ag⁺ and Ag⁰. • Summarizing Cu-based catalysts to maximize the expected different products. [ABSTRACT FROM AUTHOR]