Surfactant-assisted synthesis of mesoporous hafnium- imidazoledicarboxylic acid hybrids for highly efficient hydrogen transfer of biomass-derived carboxides

Abstract

Catalytic transfer hydrogenations of biomass-derived carbonyl compounds to produce corresponding alcohols are important pathway for biomass transformation. Herein, a facile route was developed to synthesize the surfactant-assisted heterogeneous acid-base bifunctional 4,5-imidazoledicarboxylic acid-hafnium hybrid catalyst (Hf-H3IDC-T) by hydrothermal self-assembly method. The as-prepared Hf-H3IDC-T was characterized by SEM and TEM, FT-IR spectra, N2 adsorption-desorption, X-ray diffraction patterns (XRD), X-ray photoelectron spectroscopy (XPS), Thermogravimetry analysis (TG), NH3/CO2-TPD, NMR, GCMS, ICP-OES and elemental analysis. Hf-H3IDC-T hybrid had mesoporous structure and acid-base couple sites. A quantitative yield (99.2%) of furfuryl alcohol (FFA) was obtained from furfural (FUR) over Hf-H3IDC-T using 2-propanol as the hydrogen source under mild conditions. It's found that the amino groups on the imidazole ring is beneficial to enhance the base sites of catalyst. Meanwhile, the addition of hexadecyl trimethyl ammonium bromide (CTAB) as template agents can improve the specific surface area of the catalyst. Dynamic analysis showed that the apparent activation energy of FUR reduction was as low as 50.89 kJ / mol. The as-prepared catalyst has good stability and can be recycled. Finally, the catalyst also has a good catalytic effect on the hydrogenation reaction of aldehydes and ketones of biomass-derived compounds.