Efficient Depolymerization of Polyester and Polycarbonate Plastic Waste Catalyzed by Commercially Available Homogeneous and Heterogeneous Manganese Catalysts

This work describes the depolymerization of several polyester and polycarbonate plastic waste in value-added compounds catalyzed by the air stable, cheap and commercially available manganese compounds Mn(OTf)2, Mn2(CO)10, MnBr(CO)5, and MeCpMn(CO)3 using boranes and silanes as the reducing agents with good to excellent yields. Commercial heterogeneous manganese catalyst, manganeses(II) ethyl/butyl phosphonate silica (Si-Mn), has also proven to be very efficient in the reductive depolymerization of a variety of polyesters and the polycarbonate PC.BPA. The use of Mn(OTf)2, Mn2(CO)10 and Si-Mn in consecutive depolymerization of polyesters is also investigated, showing that these catalysts remain their excellent activity after several reactions. New catalytic systems for the efficient depolymerization of plastic waste combining the use of commercially available catalysts containing an earth-abundant metal with mild and easy-to-handle reducing agent.image