Sulfonated graphitic carbon nitride as a highly selective and efficient heterogeneous catalyst for the conversion of biomass-derived saccharides to 5-hydroxymethylfurfural in green solvents

Abstract

The catalytic conversion of biomass-derived chemicals to value added products is currently a topic of high importance, as it addresses the problems pertaining to both energy and the environment. In this regard, it is pertinent to design and develop catalysts using low cost and Earth abundant materials, which could perform these biomass conversion reactions in environment friendly green solvents. Keeping these aspects in mind, we have designed and developed a heterogeneous catalyst, sulfonated graphitic carbon nitride (S-GCN), which possesses amphoteric properties by having both Brønsted base and Brønsted acid sites. Subsequently, we have used this catalyst for the conversion of different biomass-derived saccharides (glucose, fructose, cellobiose, sucrose and starch) to a highly selective value added product, 5-hydroxymethylfurfural (5-HMF), which is a platform chemical for biodiesel and other fuels. All the reactions have been performed in green solvents, such as water, ethanol, isopropyl alcohol and dimethyl carbonate, and good yields have been obtained. The detailed optimization of the reaction conditions (temperature, time and catalyst amount) has also been performed, in addition to the calculation of green metric parameters. Furthermore, the synthesized 5-HMF can also be transformed to various other value added products, such as 2,5-bis(hydroxymethyl)furan, 5-(chloromethyl)furfural and 5-(bromomethyl)furfural. Moreover, the catalyst showed easy separation and good recyclability and also maintained structural integrity, which makes it a sustainable catalyst with high efficiency for the conversion of biomass-derived chemicals to value added products.