Mechanisms of Palladium Catalyst Poisoning by Unreacted Phenylethyl Alcohol Derivatives and Residual Acetone During Fexofenadine Hydrogenation
Patent literature, including WO2007007347A1, highlights the use of acetone in dehydration steps for Fexofenadine hydrochloride manufacturing. Incomplete removal of acetone introduces a significant risk during subsequent hydrogenation stages. Acetone molecules compete with the substrate for adsorption on palladium catalyst surfaces, effectively reducing the available active sites and slowing reaction kinetics. Furthermore, unreacted phenylethyl alcohol derivatives, which may arise from partial hydrolysis or side reactions, exhibit strong coordination affinity to metal centers. These species can cause irreversible catalyst poisoning, necessitating frequent catalyst replacement and increasing operational downtime. NINGBO INNO PHARMCHEM CO.,LTD. emphasizes the importance of rigorous solvent removal and impurity control in
