Selective hydroconversion of 5-hydroxymethylfurfural to 2,5-bis(hydroxymethyl)furan using carbon nanotubes-supported nickel catalysts

2,5-Bis(hydroxymethyl)furan (BHMF) is a high-value, bio-based, rigid diol that resembles aromatic monomers for the production of different polyesters. In this work, a carbon nanotubes (CNTs)-supported nickel catalyst (Ni/CNTs) was prepared and used for the selective hydrogenation of 5-hydroxymethylfurfural (HMF) to BHMF at low hydrogen pressure. The prepared catalyst was analyzed by nitrogen adsorption–desorption isotherms, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). According to kinetic studies, the rate constant for BHMF formation is significantly larger than that for the formation of the byproduct, 5-methyl furfural (MF). At optimal reaction conditions, conversion and selectivity rates of HMF and BHMF were 99.8 % and 95.0 %, respectively. The mechanistic study indicated the coexistence of Ni⁰ and Ni²⁺ species on the catalyst surface affects the catalytic performance. A possible mechanism was proposed to describe the synergetic effects of Ni⁰ and Ni²⁺. Furthermore, the catalyst can be easily separated from the reaction mixture for recycling.