Influence of the catalytic system on the methanolysis of polyethylene terephthalate at mild conditions: A systematic investigation

Tollini, Flavio; Brivio, Lorenzo; Innocenti, Paolo; Sponchioni, Mattia; Moscatelli, Davide

doi:10.1016/j.ces.2022.117875

Cited by 18 publications

(15 citation statements)

References 32 publications

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“…Strongly nucleophilic alkoxides, such as methoxide for methanolysis, have been found to be effective and enable methanolysis depolymerization at low temperatures. 93,107,108 Heterogeneous catalysts have been considered, but we expect them to be unfavorable in most cases. It is difficult for an ester site on a solid polymer to access catalytic sites on a solid catalyst.…”

Section: Summary Of Experimental Findings 311 Stoichiometrymentioning

confidence: 99%

“…There is considerable evidence of mass-transfer limitation of the depolymerization reaction rates, particularly when PET is in the solid phase. The particle size of PET was demonstrated to affect reaction rates by several studies. ,,,− Non-reactive cosolvents have also been demonstrated to improve reaction rates. ,,,,− Phase-transfer catalysts (PTCs) are a type of cosolvent used in low concentrations to improve alkaline hydrolysis reaction rates. ,,, The PTCs are salts with lipophilic tails that allow hydroxide anions to access ester sites more easily on PET, improving reaction rates. Mass-transfer transport limitations can limit how effective a catalyst can be, if reaction rates are limited by mass-transfer effects rather than reaction kinetics.…”

Section: Depolymerization Process Chemistrymentioning

confidence: 99%

“…Hydrolysis reactions typically utilize strongly electrophilic acids or nucleophilic bases. Strongly nucleophilic alkoxides, such as methoxide for methanolysis, have been found to be effective and enable methanolysis depolymerization at low temperatures. ,, …”

Section: Depolymerization Process Chemistrymentioning

confidence: 99%

“…Low-temperature methanolysis reactions are relatively new to the literature. The recent studies by Pham and Cho and Tollini et al are likely inspired by the Loop Industries process, which published patents as early as 2019. − Reaction temperatures have been demonstrated below 100 °C, enabling the reactor to operate at or close to ambient pressure. The catalysts are strong nucleophiles, such as methoxide, or weaker nucleophiles, such as potassium carbonate.…”

Section: Depolymerization Process Chemistrymentioning

confidence: 99%

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Assessment of PET Depolymerization Processes for Circular Economy. 1. Thermodynamics, Chemistry, Purification, and Process Design

McNeeley,

Liu

2024

Ind. Eng. Chem. Res.

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Poly(ethylene terephthalate) (PET) is the most widely produced thermoplastic and is used in drink bottles, packaging, and textiles. Chemical depolymerization represents a way to recycle PET that is robust to the low purity and quality of some waste PET sources. This work investigates the three primary routes to depolymerize PET into feedstocks used to produce the PET polymer: methanolysis, glycolysis, and hydrolysis. This work is unique in providing a thorough review of the depolymerization thermodynamics, chemistry, purification strategies, and design of PET depolymerization processes from an industrial perspective. This work provides detailed descriptions of different variants of PET depolymerization processes. We summarize available data necessary to design a PET depolymerization process and indicate where gaps in data exist. We demonstrate the importance of separation and purification sections of the process, which are rarely addressed in academic literature. We also demonstrate different designs and strategies that industrial technologies employ to address challenges.

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Section: Summary Of Experimental Findings 311 Stoichiometrymentioning

confidence: 99%

Section: Depolymerization Process Chemistrymentioning

confidence: 99%

Section: Depolymerization Process Chemistrymentioning

confidence: 99%

Section: Depolymerization Process Chemistrymentioning

confidence: 99%

See 2 more Smart Citations

Assessment of PET Depolymerization Processes for Circular Economy. 1. Thermodynamics, Chemistry, Purification, and Process Design

McNeeley,

Liu

2024

Ind. Eng. Chem. Res.

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“…158 Mild methanolysis conditions have been reported with respectable yields of DMT (71−86%) attainable at 70 °C using MeOK, K 2 CO 3 , or TBD as catalyst. 159 In turn, the reaction time was 20 h. Pham and Cho obtained 93.1% DMT yields at 25 °C after 24 h, by including DCM cosolvent. 160 Dependence on halogenated solvents like DCM is not environmentally preferable.…”

Section: Methanolysismentioning

confidence: 99%

Depolymerization within a Circular Plastics System

Clark,

Shaver

2024

Chem. Rev.

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The societal importance of plastics contrasts with the carelessness with which they are disposed. Their superlative properties lead to economic and environmental efficiency, but the linearity of plastics puts the climate, human health, and global ecosystems at risk. Recycling is fundamental to transitioning this linear model into a more sustainable, circular economy. Among recycling technologies, chemical depolymerization offers a route to virgin quality recycled plastics, especially when valorizing complex waste streams poorly served by mechanical methods. However, chemical depolymerization exists in a complex and interlinked system of end-of-life fates, with the complementarity of each approach key to environmental, economic, and societal sustainability. This review explores the recent progress made into the depolymerization of five commercial polymers: poly(ethylene terephthalate), polycarbonates, polyamides, aliphatic polyesters, and polyurethanes. Attention is paid not only to the catalytic technologies used to enhance depolymerization efficiencies but also to the interrelationship with other recycling technologies and to the systemic constraints imposed by a global economy. Novel polymers, designed for chemical depolymerization, are also concisely reviewed in terms of their underlying chemistry and potential for integration with current plastic systems.

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Circular Economy and Chemical Conversion for Polyester Wastes

Cao,

Qiu,

Zhang

et al. 2024

ChemSusChem

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Polyester waste in the environment threatens public health and environmental ecosystems. Chemical recycling of polyester waste offers a dual solution to ensure resource sustainability and ecological restoration. This minireview highlights the traditional recycling methods and novel recycling strategies of polyester plastics. The conventional strategy includes pyrolysis, carbonation, and solvolysis of polyesters for degradation and recycling. Furthermore, the review delves into exploring emerging technologies including hydrogenolysis, electrocatalysis, photothermal, photoreforming, and enzymatic for upcycling polyesters. It emphasizes the selectivity of products during the polyester conversion process and elucidates conversion pathways. More importantly, the separation and purification of the products, the life cycle assessment, and the economic analysis of the overall recycling process are essential for evaluating the environmental and economic viability of chemical recycling of waste polyester plastics. Finally, the review offers perspective into the future challenges and developments of chemical recycling in the polyester economy.

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Influence of the catalytic system on the methanolysis of polyethylene terephthalate at mild conditions: A systematic investigation

Cited by 18 publications

References 32 publications

Assessment of PET Depolymerization Processes for Circular Economy. 1. Thermodynamics, Chemistry, Purification, and Process Design

Assessment of PET Depolymerization Processes for Circular Economy. 1. Thermodynamics, Chemistry, Purification, and Process Design

Depolymerization within a Circular Plastics System

Circular Economy and Chemical Conversion for Polyester Wastes

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