Kinetics of hydrolysis of poly(ethylene terephthalate) wastes catalyzed by dual functional phase transfer catalyst: A mechanism of chain-end scission

• Using quantification of ethylene glycol (EG) formed to describe the reaction rate.
• Feasible and accurate kinetic analysis.
• Hydrolysis occurring on the polymer chain end section.
• Reaction rate and activation energy derived.

The dual functional phase transfer catalyst [(CH3)3N(C16H33)]3[PW12O40] was used in the hydrolysis of poly(ethylene terephthalate) (PET) wastes and exhibited outstanding catalytic activity. In this work, the kinetic study about this reaction was carried out. The quantification of ethylene glycol (EG) formed in the hydrolysis was used to describe the reaction rate, which could result in more feasible and accurate kinetic analysis than terephthalic acid (TPA) formation or PET consumption used in traditional method. The results of kinetic analysis showed that the depolymerization reaction rate was first order to PET and catalyst concentration. This indicated that the ester linkages on the surface of the PET sequentially reacted with water to produce products. A mechanism for the reaction occurring on the polymer chain end section was proposed. Also the activation energy value was derived. Kinetic correlations provided a reliable mathematical reaction model for this recycling process, which is in agreement with the principles of sustainable development.

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