Hydrogenation of 5-hydroxymethylfurfural to 2,5 dimethylfuran over nickel supported tungsten oxide nanostructured catalyst

Abstract

2,5 Dimethylfuran (DMF) can be considered as a promising new generation alternative fuel, which has the potential to solve the fossil fuel shortage and also the ongoing global warming issues. Although there are several reports in the literature on the production of DMF from 5-hydroxymethylfurfural, in most of the cases, the operating pressure is very high and expensive metals, such as Pd, Pt, and Rh, have been used in the presence of organic solvents. Herein, we report the preparation of nickel oxide nanoparticles supported on nanostructured tungsten oxide and the use of this catalyst as a heterogeneous catalyst for the selective hydrogenation of the biomass-derived platform molecule 5-hydroxymethylfurfural (HMF) to 2,5-dimethylfuran (DMF), a liquid fuel, at 10 bar H₂ pressure and 180 °C temperature in an aqueous medium. The catalyst was characterized using XRD, TEM, SEM, XPS, Raman and FTIR spectroscopies, TGA, and ICP-AES techniques. The catalyst showed >99% conversion of HMF with 95% selectivity of DMF without the use of any additives under optimized reaction conditions. The effect of reaction parameters, such as temperature, pressure of H₂, and the loadings of Ni, was investigated and has been discussed in detail. The reusability of the catalyst was tested by conducting repeat experiments with the spent catalyst, where it was found that the catalyst displayed no changes in its activity and selectivity even after 5 successive runs. Based on the experimental results, a possible reaction pathway has been proposed.