Metal-catalysed Poly(Ethylene) terephthalate and polyurethane degradations by glycolysis

The recovery of Polyol from PolyUretane (PU) and Bis(2-HydroxyEthyl) Terephthalate (BHET) from Poly(Ethylene) Terephthalate (PET) from plastic waste by transesterification reactions was achieved, by using a wide scope of simple air-stable metal salts, Lewis acids, mixtures of commercially available phosphine/phosphite ligands with metal salts and low-valent [Ni(COD)(2)] as catalytic precursors, in the presence of ethyleneglycol as a transesterification agent. A kinetic study with cobalt chloride led to the conclusion that the PET degradation with metal salts behaves as a consecutive reaction with an induction period. The use of sigma-donor or sigma-donor/pi-acceptor bidentate phosphine ligands, such as dcype and dppe, along with CoCl2 or [Ni(COD)(2)] improved the PET degradation process. For both rigid and flexible PU, FeCl3 was the most active catalyst precursor. (C) 2019 Elsevier B.V. All rights reserved.