Hydrogenation of succinic acid to 1,4-butanediol over Re-Ru bimetallic catalysts supported on mesoporous carbon

A series of Re-Ru bimetallic catalysts supported on mesoporous carbon (denoted as (0.6 x)Re-xRu/MC) were prepared by a single-step surfactant-templating method and a subsequent incipient wetness impregnation method with a variation of ruthenium loading (x, mol%), and they were applied to the liquid-phase hydrogenation of succinic acid to 1,4-butanediol (Boo). The effect of metal content on the catalytic activities and physicochemical properties 01 (0.6 x)Re-xRu/MC catalysts was investigated. It was found that a Re-Ru miscible phase was formed in the catalysts during the reduction process, and it was responsible for strong interaction between rhenium and ruthenium. It was also revealed that reducibility, metal dispersion, and oxidation state 01 (0.6 x)Re-xRu/MC catalysts were affected by Re:Ru molar ratio. In particular, the oxidation state was closely related to the hydrogen adsorption behavior of the catalysts. The amount of weak hydrogen-binding sites increased with increasing the ratios of metallic rhenium (Re) and ruthenium (Ru) with respect to total metallic species in the reduced (0.6 x)Re-xRu/MC catalysts. Catalytic performance in the hydrogenation of succinic acid to BDO over (0.6 x)Re-xRu/MC showed a volcano-shaped trend with respect to Re:Ru molar ratio. This result was well correlated with the amount of weak hydrogen-binding sites of the catalysts. Among the catalysts tested, 0.3Re-0.3Ru/MC with the largest amount of weak hydrogen-binding sites showed the best catalytic performance in the BDO production by hydrogenation of succinic acid. (C) 2014 Elsevier B.V. All rights reserved.