Depolymerization of polyethylene terephthalate with glycol under comparatively mild conditions

Huang, Junjie; Yan, Dongxia; Zhu, Qingqing; Cheng, Xiujie; Tang, Jing; Lü, Xingmei; Xin, Jiayu

doi:10.1016/j.polymdegradstab.2022.110245

Cited by 10 publications

(4 citation statements)

References 28 publications

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“…In addition to the primary monomers highlighted in Figure 9 , Table 2 also identifies secondary products (byproducts) that can form during these chemical reactions. Thus, one may see that glycolysis offers some key benefits, including high monomer yields and purity, short reaction time (20–60 min), milder operating conditions, low volatility of ethylene glycol (EG), and minimal by-product generation [ 112 ]. These attributes make glycolysis well-suited for large-scale applications.…”

Section: Pet Recycling Approachesmentioning

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: Pet Recycling Approachesmentioning

confidence: 99%

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

Enache,

Grecu,

Samoila

2024

Materials

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“…This BHET monomer has been successfully utilized in the synthesis of highperformance materials . [9,10] Literature reports demonstrate the versatility of BHET, derived from PET waste via glycolysis, as a valuable precursor for various polymers and materials. These include alkyd resins, polyurethane dispersions, unsaturated polyesters, textile dyestuffs, polyurethanes, epoxies, etc.…”

Section: Introductionmentioning

confidence: 99%

Chemical recycling of PET waste and utilization of recycled product for synthesis of hybrid unsaturated polyester – urethane coatings

Jamdar,

Kathalewar,

Sane

et al. 2024

Preprint

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Chemical recycling of Polyethylene terephthalate (PET) waste has gained importance in last few decades due to its dramatic consumption through its variety of applications. This study employed conventional heating-mediated glycolysis of PET waste with excess ethylene glycol, catalyzed by zinc acetate, to achieve the monomeric product bis(2-hydroxyethyl terephthalate) (BHET). Further ,three different hybrid unsaturated polyester urethane resins were synthesized using recycled product BHET, urethane diol which was synthesized using non isocyanate route of urethane synthesis, maleic anhydride and varying concentration of dimer fatty acid, citric acid and phthalic anhydride. These synthesized novel resins, Hybrid Unsaturated polyester – urethane possessed the unsaturated ester as well as urethane linkages in their polymer backbone. Comprehensive characterization of the synthesized hybrid resins and monomeric urethane diol was performed using established techniques. This included determination of hydroxyl value, iodine value, and molecular weight via Gel Permeation Chromatography (GPC). Additionally, Fourier-Transform Infrared Spectroscopy (FTIR) and ¹H Nuclear Magnetic Resonance (NMR) spectroscopy were employed for structural elucidation. Subsequently, the formulated hybrid polyester urethane resins were cured at room temperature using a styrene monomer, methyl ethyl ketone peroxide (MEKP) initiator, and cobalt salt accelerator. A rigorous evaluation of the cured coatings was conducted to determine their optical properties, mechanical performance, and chemical resistance. These properties are crucial for understanding the films' potential applications Finally, thermal behavior was investigated using Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA).

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“…[19][20][21] Among the suggested chemical recovery technologies for waste PET, hydrolysis, alcoholysis and ammonolysis appear to be the most promising approaches. [22][23][24] Alcoholysis of waste PET with ethylene glycol, 25 isooctanol, 26 or methanol 27 can provide valuable products, such as 1,4-dihydroxyethyl terephthalate (BHET), 1,4-dioctyl terephthalate (DOTP), or dimethyl terephthalate (DMT), respectively. It has been reported that ionic liquids, 28 sodium carbonate, 29 deep eutec-tic solvents, 30 Fe 3 O 4 31 and nano-sized ZnO 32 are capable of catalyzing the alcoholysis of PET with ethylene glycol to yield BHET.…”

Section: Introductionmentioning

confidence: 99%

Upcycling of waste polyethylene terephthalate to dimethyl terephthalate over solid acids under mild conditions

Ye¹,

Zhou²,

Zhong³

et al. 2023

Green Chem.

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Depolymerization of polyethylene terephthalate with glycol under comparatively mild conditions

Cited by 10 publications

References 28 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

Chemical recycling of PET waste and utilization of recycled product for synthesis of hybrid unsaturated polyester – urethane coatings

Upcycling of waste polyethylene terephthalate to dimethyl terephthalate over solid acids under mild conditions

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