Selective Catalytic Hydrogenation of Reducing and Keto Sugars to the Corresponding Alcohols over Silica‐Supported Nanoscale Nickel Catalyst under Low Hydrogen Pressure

ABSTRACT A fumed silica‐supported nanoscale nickel catalyst (Ni/SiO 2 ) was synthesized via a simple chemical reduction method using NaBH 4 as the reducing agent. The well‐characterized Ni/SiO 2 catalyst exhibited remarkable activity for the hydrogenation of reducing and keto sugars to the corresponding sugar alcohols under mild aqueous conditions and low hydrogen pressure. The crude reaction products were systematically analysed by NMR and HPLC. Notably, the 15% Ni/SiO 2 catalyst achieved excellent lactose conversion (99%) and lactitol selectivity (96%) at 10 bar H 2 . The catalyst retained its activity after two successive recycling runs, maintaining high lactose conversion (99%) and lactitol selectivity (90%). Furthermore, the catalyst demonstrated high conversion (75%–99%) and selectivity (92%–99%) for various reducing and keto sugars under optimized conditions. For comparison, a commercial Raney Ni catalyst afforded only 13% lactose conversion under identical conditions. These results highlight that the well‐dispersed nano‐nickel on silica support is significantly more efficient than conventional nickel‐based catalysts, including the Raney Ni, for sugar hydrogenation.