A facile approach toward the synthesis of terephthalic acid via aminolytic depolymerization of PET waste and studies on the kinetics of depolymerization

Abstract

AbstractIn this polymer‐governing era, polyethylene terephthalate (PET) has become one of the most demanding consumables. This growing interest in the production and consumption of plastic products results in an increase in the volume of post‐consumer plastic waste. However, due to the growing concern for environmental protection, recycling PET waste to the valuable ones has become one of the hot topics in contemporary research. In this study, PET waste was depolymerized using ethanolamine as a depolymerizing agent. N,N′‐Bis(2‐hydroxyethyl)terephthaldiamide (BHETA) (yield 77%) was obtained after depolymerization of PET via ethanolamine. The characterization of the monomer BHETA was done using FTIR, 1H NMR, and FE‐SEM. The thermal stability of PET and BHETA was done using TGA analysis. To avoid the extreme reaction condition (high temperature and high pressure) of conventional way to form terephthalic acid (TPA) via hydrolysis of PET waste, in this study, a facile way is performed. The monomer BHETA was converted to a main building block of PET (TPA) (yield 67%) using strong oxidizing agent KMnO4 in mild reaction conditions at room temperature and pressure. The synthesized TPA was characterized using FTIR and 1H NMR. This work also focuses on the anticipation of the reaction progress of aminolysis of PET using simple analytical tools namely, FTIR and TGA.