Development of an acid-resistant solid-base catalyst for polycarbonate phenolysis

Abstract

Abstract The phenolysis of polycarbonate using solid-base catalysts results in the depolymerization of polycarbonate into its precursors, i.e., bisphenol A and diphenyl carbonate, giving it potential applications in chemical recycling. Owing to the high acidity of phenol, solid-base catalysts must exhibit acid resistance. We evaluated the catalytic activity and leaching resistance of solid-base catalysts in the phenolysis of polycarbonate. The results indicated a tendency for increased leaching with larger metal ion radii among the synthesized solid-base catalysts. Nonetheless, MgO, which had a small metal ion radius, exhibited excellent leaching resistance. However, owing to the acidic nature of phenol, MgO was deactivated by the adsorption of phenol on its basic sites. Immobilizing MgO on an acidic support reduced its basic strength, inhibiting phenol adsorption and mitigating deactivation. Notably, MgO/Al2O3 was identified as a catalyst with an optimal basic strength for both catalytic activity and deactivation suppression.