Sustainable production of succinic acid (SA) from tartaric acid (TA) is achieved by ReO_x/AC catalyst in water. High TON and SA productivity are obtained, and the reaction is scalable up to the gram-scale. Water promotes the hydrogenation rate by more than one order of magnitude compared to organic solvents (dioxane). In situ-generated Re^IV is presumed to be an active species. Re-sintering and leaching are possible causes of deactivation.

Abstract

The formation of dicarboxylic acid from biomass waste is an important topic for the sustainable production of polymers. Rhenium-catalyzed deoxydehydration (DODH) of aldaric acid to enedioic acid, followed by hydrogenation (HG), is one of the possible routes to form carboxylic acids. However, reliance on organic solvents and noble metals poses a risk to the sustainability of the process. Herein, we demonstrated for the first time the conversion of tartaric acid (TA) to succinic acid (SA) in water in a one-pot reaction using heterogeneous ReO_x/activated carbon (ReO_x/AC) without the addition of noble metals, in which ReO_x/AC catalyzes both DODH and HG. At TA conversion >99%, SA yield of 76% is obtained. TA concentrations as high as 10 wt.% could be employed, and unprecedentedly high turnover number (TON, 144) and SA productivity (0.24 g_SA·g_catalyst ⁻¹·h⁻¹) are obtained. The use of water facilitates the HG of fumaric acid intermediate, showing a 17-fold faster HG step compared to conventional dioxane. The catalyst was reused over four reaction cycles.