Transfer hydrogenation of ketone; an in situ approach toward an eco-friendly reduction

The use of water as a solvent in chemical reactions has recently been brought to public attention, especially in the exploration of eco-friendly procedures. It is readily available, abundantly accessible, non-toxic, non-flammable, and at a low cost. As opposed to the previous limitation of reactant solubilities associated with aqueous media, a hydrogel such as a hydroxypropyl methylcellulose (HPMC) solution can significantly improve the reactant solubility. This investigation employed water and HPMC as the reaction solvent, and the reaction medium viscosity was impressively enhanced. Silica-supported Pd particles (Pd@SiO₂) were synthesized and effectively catalyzed the reduction of acetophenone in the presence of sodium borohydride (NaBH₄) as the hydrogen source. The conversion of acetophenone to 1-phenyl ethanol remained at a very high value of >99.34% with 100% selectivity towards 1-phenyl ethanol.