Metal Octoates as Lewis Acid Catalysts for the Hydrolytic Depolymerization of PET in Tetrahydrofuran
4 affiliations
- 1Scientific and Educational Center “Materials”, Don State Technical University, 1 Gagarin Square, 344003 Rostov-on-Don, Russia
- 2LLC “Himpostavshchik-Don”, 346720 Aksai, Russia
- 3Research Institute “Nanotechnologies and New Materials”, Platov South-Russian State Polytechnic University, 346428 Novocherkassk, Russia
- 4Laboratory of Polymer Materials and Composites Technology, Tula State University, 92 Lenin Ave, 300012 Tula, Russia
Abstract
Chemical recycling of polyethylene terephthalate (PET) with decomposition into monomers suitable for resynthesizing primary polymer is a critical task for achieving carbon neutrality in the polyester industry. This paper presents a study comparing PET depolymerization solvolysis in tetrahydrofuran medium using a series of metal octoates (Co, Mn, Zn, Ca, Ba, Li, Zr, Cu, Pb). The resulting terephthalic acid (TPA) was characterized using a combination of methods (1H NMR, thermogravimetric analysis, differential scanning calorimetry, and Raman spectroscopy). In an aprotic tetrahydrofuran (THF) medium, a comparative performance of commercial metal octoates under fixed metal-mass loading was conducted for the first time: the leadership of Co (83.7%) and Pb (78.4%) is explained by the lability of their coordination sphere, while the anomalously low activity of Zr (17.5%) is associated with steric blocking of the metal active center. In the present work, the influence of technological parameters on the depolymerization process using the most active catalyst, cobalt octoate, was studied. It was found that increasing the reaction time from 1 to 6 h leads to an increase in PET conversion from 27% to ~85%, and in TPA yield from 14% to ~84%. A study of the influence of water content in the reaction mixture showed that increasing the water concentration to 20 wt.% intensifies hydrolysis, promoting an increase in the yield of TPA to ~80%; however, a further increase in the water content (up to 30 wt.%) does not lead to a significant change in the yield, which indicates the achievement of conditions providing the highest observed isolated TPA yield within the tested range for the reaction in this system. The obtained results create a scientific basis for the rational design of catalytic systems for the depolymerization of PET, adapted to the different qualities of secondary raw materials and the technological requirements of industrial chemical recycling.
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BibTeX
@article{zubkov2026metal,
title = {{Metal Octoates as Lewis Acid Catalysts for the Hydrolytic Depolymerization of PET in Tetrahydrofuran}},
author = {Ivan N. Zubkov and Sergey A. Lavrenov and Yuri V. Korolev and Ekaterina A. Korsunova and Alina A. Petrenko and Dmitry S. Petrenko and Evgeniy V. Sadyrin and Alexey N. Saliev and Olga P. Papeta and Daniil V. Telegin and Victor A. Klushin},
journal = {Catalysts},
year = {2026},
month = oct,
doi = {10.3390/catal16100914},
url = {https://www.mdpi.com/2073-4344/16/10/914},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Metal Octoates as Lewis Acid Catalysts for the Hydrolytic Depolymerization of PET in Tetrahydrofuran
AU - Ivan N. Zubkov
AU - Sergey A. Lavrenov
AU - Yuri V. Korolev
AU - Ekaterina A. Korsunova
AU - Alina A. Petrenko
AU - Dmitry S. Petrenko
AU - Evgeniy V. Sadyrin
AU - Alexey N. Saliev
AU - Olga P. Papeta
AU - Daniil V. Telegin
AU - Victor A. Klushin
PY - 2026
DA - 2026/10/16
JO - Catalysts
DO - 10.3390/catal16100914
UR - https://www.mdpi.com/2073-4344/16/10/914
AB - Chemical recycling of polyethylene terephthalate (PET) with decomposition into monomers suitable for resynthesizing primary polymer is a critical task for achieving carbon neutrality in the polyester industry. This paper presents a study comparing PET depolymerization solvolysis in tetrahydrofuran medium using a series of metal octoates (Co, Mn, Zn, Ca, Ba, Li, Zr, Cu, Pb). The resulting terephthalic acid (TPA) was characterized using a combination of methods (1H NMR, thermogravimetric analysis, differential scanning calorimetry, and Raman spectroscopy). In an aprotic tetrahydrofuran (THF) medium, a comparative performance of commercial metal octoates under fixed metal-mass loading was conducted for the first time: the leadership of Co (83.7%) and Pb (78.4%) is explained by the lability of their coordination sphere, while the anomalously low activity of Zr (17.5%) is associated with steric blocking of the metal active center. In the present work, the influence of technological parameters on the depolymerization process using the most active catalyst, cobalt octoate, was studied. It was found that increasing the reaction time from 1 to 6 h leads to an increase in PET conversion from 27% to ~85%, and in TPA yield from 14% to ~84%. A study of the influence of water content in the reaction mixture showed that increasing the water concentration to 20 wt.% intensifies hydrolysis, promoting an increase in the yield of TPA to ~80%; however, a further increase in the water content (up to 30 wt.%) does not lead to a significant change in the yield, which indicates the achievement of conditions providing the highest observed isolated TPA yield within the tested range for the reaction in this system. The obtained results create a scientific basis for the rational design of catalytic systems for the depolymerization of PET, adapted to the different qualities of secondary raw materials and the technological requirements of industrial chemical recycling.
SN - 2073-4344
ER -