Mechanistic Insights into Zinc Acetate Dihydrate–Catalyzed Depolymerization of Recycled PET for Polyol Production: A Combined Experimental and DFT Study
Abstract
Transforming recycled polyethylene terephthalate (rPET) waste into high-value polyols offers a promising approach for sustainable polymer production. In this study, rPET/PEG-containing oligomeric polyols were synthesized through the glycolysis of rPET using polyethylene glycol 400 (PEG400) as the depolymerizing agent at an rPET:PEG400 molar ratio of 1:2. Zinc acetate dihydrate (Zn(OAc)2·2H2O) served as a transesterification catalyst, with its concentration (0.00–2.00 wt% of rPET) systematically varied to assess its effect on depolymerization efficiency and physicochemical properties. Without a catalyst, glycolysis led to incomplete rPET depolymerization. However, only 0.20 wt% Zn(OAc)2·2H2O enabled complete depolymerization, achieving a 100% conversion and a turnover frequency (TOF) of 19.89 h-1. The optimized rPET-based polyol mixture showed a hydroxyl value of 137.17 mg KOH g-1, acid value of 1.74 mg KOH g-1, and average functionality of 3.51, indicating suitability as a reactive precursor. The polyol also exhibited a broad operational temperature range (8.17–222.67°C), facilitating mixing and processing. Furthermore, DFT calculations revealed two possible glycolysis pathways and theoretically supported that Zn(OAc)2·2H2O lowers the activation energy (Ea) of the rate-determining step. These results suggest an effective catalytic route for converting rPET into oligomeric PET/PEG-containing polyol mixtures as potential precursors for polyurethane and related polymer synthesis.
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BibTeX
@article{thusanaphoom2026mechanistic,
title = {{Mechanistic Insights into Zinc Acetate Dihydrate–Catalyzed Depolymerization of Recycled PET for Polyol Production: A Combined Experimental and DFT Study}},
author = {Panachai Thusanaphoom and Nismar Parneam and Sineenard Songsri and Wichain Chailad and Yutthana Wongnongwa and Narongrit Sosa and Jennifer Rodon-Fores and Fouzia Boulmedais and Nathapong Sukhawipat},
journal = {Journal of Molecular Structure},
year = {2026},
month = sep,
doi = {10.1016/j.molstruc.2026.147752},
url = {https://hal.science/hal-05772442v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Mechanistic Insights into Zinc Acetate Dihydrate–Catalyzed Depolymerization of Recycled PET for Polyol Production: A Combined Experimental and DFT Study
AU - Panachai Thusanaphoom
AU - Nismar Parneam
AU - Sineenard Songsri
AU - Wichain Chailad
AU - Yutthana Wongnongwa
AU - Narongrit Sosa
AU - Jennifer Rodon-Fores
AU - Fouzia Boulmedais
AU - Nathapong Sukhawipat
PY - 2026
DA - 2026/09/29
JO - Journal of Molecular Structure
DO - 10.1016/j.molstruc.2026.147752
UR - https://hal.science/hal-05772442v1
AB - Transforming recycled polyethylene terephthalate (rPET) waste into high-value polyols offers a promising approach for sustainable polymer production. In this study, rPET/PEG-containing oligomeric polyols were synthesized through the glycolysis of rPET using polyethylene glycol 400 (PEG400) as the depolymerizing agent at an rPET:PEG400 molar ratio of 1:2. Zinc acetate dihydrate (Zn(OAc)2·2H2O) served as a transesterification catalyst, with its concentration (0.00–2.00 wt% of rPET) systematically varied to assess its effect on depolymerization efficiency and physicochemical properties. Without a catalyst, glycolysis led to incomplete rPET depolymerization. However, only 0.20 wt% Zn(OAc)2·2H2O enabled complete depolymerization, achieving a 100% conversion and a turnover frequency (TOF) of 19.89 h-1. The optimized rPET-based polyol mixture showed a hydroxyl value of 137.17 mg KOH g-1, acid value of 1.74 mg KOH g-1, and average functionality of 3.51, indicating suitability as a reactive precursor. The polyol also exhibited a broad operational temperature range (8.17–222.67°C), facilitating mixing and processing. Furthermore, DFT calculations revealed two possible glycolysis pathways and theoretically supported that Zn(OAc)2·2H2O lowers the activation energy (Ea) of the rate-determining step. These results suggest an effective catalytic route for converting rPET into oligomeric PET/PEG-containing polyol mixtures as potential precursors for polyurethane and related polymer synthesis.
SN - 0022-2860
SN - 0022-2860
ER -