Recycling Polyethylene terephthalate (PET) in milder and greener conditions by inserting the 2,5-dihydroxyterephthalate repeating unit.

Recycling of Polyethylene terephthalate (PET) has attracted extensive attention in recent years due to the growing utilization of single-use plastic products and subsequent accumulation in the environment. Physical recycling of PET is used industrially; however, only so much recycled material can be utilized and the number of times plastic is recycled has a significant impact on the performance. In this study, the insertion of diethyl 2,5-dihydroxyterephthalate into the backbone of PET during polymerization allows for selective and facile degradation of the produced material. By use of a 1% ZnCl2 aqueous solution, the metal ions coordinate with the functional groups ( hydroxy and ester) and allow for selective hydrolytic deconstruction of the polymer. Heating the polymer suspended in the salt solution to 180-200 °C for 2 hours allows for nearly complete (98%) deconstruction of the polymer. Following the deconstruction, the monomers (terephthalic acid and 2,5-dihydroxyterephthalic acid) and the bis(2-Hydroxyethyl) terephthalate dimer were reclaimed. This methodology demonstrates a facile, cost-effective procedure for recovering virgin monomeric units that could open the door to more efficiently recycled plastics and significantly less environmental waste.