PET glycolysis in the presence of solid CoMnAlO_x

PET glycolysis corresponds to a highly efficient Chemical recycling process, which offers some advantages over physical recycling. The main product is the Bis(2-hydroxyethyl) terephthalate – BHET, the PET monomer, which provides high-quality recycled PET, such as the one used in food packaging. BHET can also be used in the production in the production of new copolymers. PET glycolysis has its efficiency improved in the presence of a catalyst. Therefore, in the present work, Co, Mn, and Al-based oxide catalysts were synthesized by coprecipitation followed by calcining at 400 °C. These catalysts are poorly crystallized, hydrotalcite-like structured, with surface areas of 114 m².g^-1 and 103 m².g^-1, for CoMnAl and CoAl, respectively. Both catalysts were applied in the conversion of PET to BHET through glycolysis. Best results were obtained in the optimized parameters of 0.5% catalyst/PET, EG/PET = 5, reacting at 200°C in 60 minutes, which resulted in PET conversion of 96.7 and 40.2% in the presence of CoMnAl.c and CoAl.c, respectively. Both catalysts were still advantageous when compared to the non-catalysed PET glycolysis, which led to 0% PET conversion in the same optimized parameters. The results show that Mn promoted the performance of CoAl.c, which led to CoMnAl.c with a higher efficiency on PET conversion.