Abstract:
Selective hydrogenation of sugars (e.g. sucrose, cellobiose, glucose, fructose, xylose, arabinose) into sugar alcohols (sorbitol, mannitol, xylitol, arabitol) can be achieved by means of supported Raney Ni-based catalysts. Various supporting materials such as the layered structure of clay (e.g. bentonite, taeniolite, smectite), metal oxides (e.g. Nb2O5, ZrO2, Al2O3), and conventional supports (e.g. carbon, silica, zeolite (JRC-SZ1)) were employed to obtain high performance of supported Raney Ni-based catalysts. The conventional Raney Ni, Raney Ni/AlOH, and Ni-NP with relatively high dispersion exhibited superior catalytic activity compared with the various supported Raney Ni catalysts with the conversion of 100% and hexitols selectivity almost ~99%. The H2 treatment of Raney Ni/SMT at a temperature of 473–773 K caused the increase in Ni(111) crystallite sizes as the conversion of sucrose with compromised decreased of hexitols product. The presence of acidic co-catalyst such as SnO, amberlyst-15, JRC-SZ1, JRC-Z5-9OH1 on Raney Ni/AlOH catalyst significantly enhanced the formation of glycerol product even though the conversion of sucrose compromised decreased owing to the partial leaching of Ni metal into the reaction mixture.
