Effect of Supercritical CO2 as Reaction Medium for Selective Hydrogenation of Acetophenone to 1-Phenylethanol.

1-Phenylethanol (PhE) is widely employed in the pharmaceutical industry as an anti-inflammatory and analgesic drug, as well as in chewing gums and yogurts as a food additive. In this work, we have investigated the selective synthesis of 1-phenylethanol (PhE) by hydrogenation of acetophenone using supercritical CO₂ as a solvent. Supercritical carbon dioxide (scCO₂) replaces organic solvent because it is inexpensive, nontoxic, nonflammable, inert, and environmentally benign. Polyurea-based encapsulated mono- and bimetallic catalysts were synthesized and characterized using different characterization techniques. The effects of various reaction parameters, such as co-solvent, catalyst loading, hydrogen pressure, total scCO₂ pressure, and temperature, were studied to determine the reaction kinetics.