Efficient catalytic upcycling of polyester and polycarbonate plastics using an NNN-based iron catalyst

The development of efficient, eco-friendly recycling methods for mitigating the environmental impact of polyester waste remains a significant challenge. Herein, we establish an efficient catalytic system based on an NNN-based iron pincer catalyst, which can facilitate the hydrogenative depolymerization of polyester plastics using two methods. The first method is to depolymerize the polyester into ester monomers via methanolysis and facilitate subsequent transfer hydrogenation using ammonia borane as a hydrogen source to obtain diol products under mild conditions. The second method is to use molecular hydrogen as a hydrogen source for the direct catalytic hydrogenolysis of the plastic to obtain diol products. The catalyst [Fe(NNHN)Cl₂] demonstrates high catalytic efficiency in the degradation of polyester and polycarbonate plastics, including when using plastic waste from daily life as raw materials.