Solvent-free selective hydrogenation of D-glucose to D-sorbitol using different metal-supported on mesoporous titanium dioxide catalysts

Se, Bi, and Sn particles were incorporated into mesoporous TiO₂ using a conventional impregnation technique. The obtained materials were analyzed through various characterization methods, including X-ray diffraction, Fourier Transform Infrared Spectroscopy, N₂ adsorption-desorption analysis, scanning electron microscopy, transmission electron microscopy, NH₃-temperature-programmed desorption, and thermogravimetric analysis. The prepared catalyst was used to hydrogenate D-glucose into D-sorbitol under solvent-free conditions at 80°C and 10 bar for a reaction time of 2 hours. The (5 wt%)Se/TiO₂ catalyst was tested for its effectiveness in the hydrogenation of D-glucose. Hydrogenation experiments were conducted in a batch reactor to evaluate its selectivity in producing D-sorbitol. Kinetic studies were performed to analyze the hydrogenation process using this catalyst. Within the studied operating conditions, the reaction rate exhibited first-order dependence on both D-glucose and hydrogen concentrations. To achieve the highest possible D-glucose conversion, as well as optimal selectivity and yield of D-sorbitol, reaction conditions were carefully optimized. During the recycling experiments, the Se/TiO₂ catalyst was filtered and washed with isopropyl alcohol (IPA), then dried before being reused in subsequent catalytic cycles. Notably, the Se/TiO₂ catalyst demonstrated outstanding catalytic performance, achieving over 99.5 wt% conversion with more than 100% selectivity under mild temperature and pressure conditions.