Modeling of Poly(Ethylene Terephthalate) Homogeneous Glycolysis Kinetics

Kirshanov, Kirill; Томс, Р. В.; Balashov, M. S.; Golubkov, S. S.; Melnikov, Petr; Gervald, A. Yu.

doi:10.3390/polym15143146

Cited by 5 publications

(9 citation statements)

References 47 publications

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“…Their advantages include an elevated monomer yield, robust mechanical strength, high melting points, adaptability for use in fixed and fluidized beds, a regenerability potential, ease of separation, and prolonged durability [127]. As represented in Combining two oxides increases the number of catalytic sites by modifying the electronic structure of active metals, thereby enhancing the interaction between the substrate and catalyst and consequently accelerating the reaction rate [146]. As observed in Table 4, mixing metal oxides has been proved to present different behavior regarding catalytic activity, as compared with pure metal oxides.…”

Section: Oxide-based Catalystsmentioning

confidence: 99%

Polyethylene Terephthalate (PET) Recycled by Catalytic Glycolysis: A Bridge toward Circular Economy Principles

Enache,

Grecu,

Samoila

2024

Materials

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Plastic pollution has escalated into a critical global issue, with production soaring from 2 million metric tons in 1950 to 400.3 million metric tons in 2022. The packaging industry alone accounts for nearly 44% of this production, predominantly utilizing polyethylene terephthalate (PET). Alarmingly, over 90% of the approximately 1 million PET bottles sold every minute end up in landfills or oceans, where they can persist for centuries. This highlights the urgent need for sustainable management and recycling solutions to mitigate the environmental impact of PET waste. To better understand PET’s behavior and promote its management within a circular economy, we examined its chemical and physical properties, current strategies in the circular economy, and the most effective recycling methods available today. Advancing PET management within a circular economy framework by closing industrial loops has demonstrated benefits such as reduced landfill waste, minimized energy consumption, and conserved raw resources. To this end, we identified and examined various strategies based on R-imperatives (ranging from 3R to 10R), focusing on the latest approaches aimed at significantly reducing PET waste by 2040. Additionally, a comparison of PET recycling methods (including primary, secondary, tertiary, and quaternary recycling, along with the concepts of “zero-order” and biological recycling techniques) was envisaged. Particular attention was paid to the heterogeneous catalytic glycolysis, which stands out for its rapid reaction time (20–60 min), high monomer yields (>90%), ease of catalyst recovery and reuse, lower costs, and enhanced durability. Accordingly, the use of highly efficient oxide-based catalysts for PET glycolytic degradation is underscored as a promising solution for large-scale industrial applications.

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Section: Oxide-based Catalystsmentioning

confidence: 99%

Polyethylene Terephthalate (PET) Recycled by Catalytic Glycolysis: A Bridge toward Circular Economy Principles

Enache,

Grecu,

Samoila

2024

Materials

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“…It is worth noting that PLA is singled out among biopolymers because its main valuable qualities are considered to be environmental friendliness, biocompatibility and recyclability; it is non-toxic, as are its degradation products [ 5 , 6 ]. Biodegradability is one of the key advantages of PLA, distinguishing it from other polymers, the disposal of which requires mechanical (physical) [ 7 ] or chemical recycling [ 8 , 9 ] or incineration.…”

Section: Introductionmentioning

confidence: 99%

“…To synthesize pure L-lactide, it is required to use L-lactic acid and sustain the reaction conditions that minimize the production of meso-lactide. Namely, it is the necessary to maintain the temperature and pressure regime and use catalysts that allow the necessary stereospecificity to be achieved [ 8 , 9 ]. Currently, a two-step method consisting of lactic acid oligomerization followed by depolymerization to form lactide is commonly used.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of L-Lactide from Lactic Acid and Production of PLA Pellets: Full-Cycle Laboratory-Scale Technology

Aliev,

Toms,

Melnikov

et al. 2024

Polymers

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Lactide is one of the most popular and promising monomers for the synthesis of biocompatible and biodegradable polylactide and its copolymers. The goal of this work was to carry out a full cycle of polylactide production from lactic acid. Process conditions and ratios of reagents were optimized, and the key properties of the synthesized polymers were investigated. The influence of synthesis conditions and the molecular weight of lactic acid oligomers on the yield of lactide was studied. Lactide polymerization was first carried out in a 500 mL flask and then scaled up and carried out in a 2000 mL laboratory reactor setup with a combined extruder. Initially, the lactic acid solution was concentrated to remove free water; then, the oligomerization and synthesis of lactide were carried out in one flask in the presence of various concentrations of tin octoate catalyst at temperatures from 150 to 210 °C. The yield of lactide was 67–69%. The resulting raw lactide was purified by recrystallization in solvents. The yield of lactide after recrystallization in butyl acetate (selected as the optimal solvent for laboratory purification) was 41.4%. Further, the polymerization of lactide was carried out in a reactor unit at a tin octoate catalyst concentration of 500 ppm. Conversion was 95%; Mw = 228 kDa; and PDI = 1.94. The resulting products were studied by differential scanning calorimetry, NMR spectroscopy and gel permeation chromatography. The resulting polylactide in the form of pellets was obtained using an extruder and a pelletizer.

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“…An alternative method for PET recycling involves chemolysis processes, including hydrolysis, glycolysis, methanolysis, and aminolysis [7][8][9]. These processes promote depolymerization, transforming polymer molecules into monomers or oligomers that are suitable for use as raw materials in the production of new products [10,11].…”

Section: Introductionmentioning

confidence: 99%

Application of Infrared Pyrolysis and Chemical Post-Activation in the Conversion of Polyethylene Terephthalate Waste into Porous Carbons for Water Purification

Efimov,

Vasilev,

Muratov

et al. 2024

Polymers

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In this study, we compared the conversion of polyethylene terephthalate (PET) into porous carbons for water purification using pyrolysis and post-activation with KOH. Pyrolysis was conducted at 400–850 °C, followed by KOH activation at 850 °C for samples pyrolyzed at 400, 650, and 850 °C. Both pyrolyzed and post-activated carbons showed high specific surface areas, up to 504.2 and 617.7 m2 g−1, respectively. As the pyrolysis temperature increases, the crystallite size of the graphite phase rises simultaneously with a decrease in specific surface area. This phenomenon significantly influences the final specific surface area values of the activated samples. Despite their relatively high specific surface areas, pyrolyzed PET-derived carbons prove unsuitable as adsorbents for purifying aqueous media from methylene blue dye. A sample pyrolyzed at 650 °C, with a surface area of 504.2 m2 g−1, exhibited a maximum adsorption value of only 20.4 mg g−1. We propose that the pyrolyzed samples have a surface coating of amorphous carbon poor in oxygen groups, impeding the diffusion of dye molecules. Conversely, post-activated samples emerge as promising adsorbents, exhibiting a maximum adsorption capacity of up to 127.7 mg g−1. This suggests their potential for efficient dye removal in water purification applications.

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Modeling of Poly(Ethylene Terephthalate) Homogeneous Glycolysis Kinetics

Cited by 5 publications

References 47 publications

Polyethylene Terephthalate (PET) Recycled by Catalytic Glycolysis: A Bridge toward Circular Economy Principles

Polyethylene Terephthalate (PET) Recycled by Catalytic Glycolysis: A Bridge toward Circular Economy Principles

Synthesis of L-Lactide from Lactic Acid and Production of PLA Pellets: Full-Cycle Laboratory-Scale Technology

Application of Infrared Pyrolysis and Chemical Post-Activation in the Conversion of Polyethylene Terephthalate Waste into Porous Carbons for Water Purification

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