Biochar as a catalytic material for the production of 1,4-butanediol and tetrahydrofuran from furan.

Biomass valorization is emerging as a new trend for the synthesis of materials for various environmental applications. In this connection, a biochar resulting from pyrolysis of rice straw was employed as a catalytic material for the conversion of hemicellulose-derived furan into value-added platform chemicals such as 1,4-butanediol (1,4-BD) and tetrahydrofuran (THF). The biochar was used as catalyst support of bifunctional Ru-Re catalyst. Two different catalysts were prepared: a conventional activated carbon (AC)-supported Ru-Re catalyst (Ru-Re/AC) and a biochar-supported Ru-Re catalyst (Ru-Re/biochar). The Ru-Re/biochar had a different form of Re species from the Ru-Re/AC, resulting in different reducibility. The difference of reducibility between the two was attributed to alkali metal present in the biochar such as potassium. The Ru-Re/biochar had a 17 times lower metal dispersion on the surface than the Ru-Re/AC, ascribed to a lower surface area of the biochar than the AC. Catalytic activities of the catalysts with regard to reaction rate per available surface active site for transforming furan to 1,4-BD and THF were measured. The Ru-Re/AC was 3 times less active than the Ru-Re/biochar. This study not only provides a way to efficiently use biomass both for environmental catalysts and for feedstock of producing value-added platform chemicals, but also shows potential of biochar for the replacement of typical catalysts employed in biorefinery.