In Situ Experimental Study on High‐Temperature Hydrolysis of Polyethylene Terephthalate

ABSTRACT Hydrolysis is a key method for recycling polyethylene terephthalate (PET). In this study, high‐temperature hydrolysis of PET was investigated using in situ observations and Raman spectroscopy in a fused silica capillary reactor (FSCR) at temperatures up to 330°C. When the temperature was increased from room temperature to 250°C, the shape of the sample changed drastically, and accordingly, Raman spectroscopy detected a change in the internal structure of the sample, indicating that the PET sample began to enter a molten state at this temperature. The residual substances in the liquid after the reaction were ethylene glycol (EG) and terephthalic acid (TPA), demonstrating that the experimental process involved a hydrolysis reaction. It was found that the hydrolysis of PET at high temperatures follows a logistic model, with a slow‐fast‐slow trend, where the reaction rate increases with increasing temperature. Based on kinetic analysis, the activation energy for PET hydrolysis at high temperatures is ~135 kJ∙mol −1 . These findings deepen our understanding of PET hydrolysis, offering insights to improve recycling strategies and promote environmental sustainability.