Highly Efficient Depolymerization of Waste Polyesters Enabled by Transesterification/Hydrogenation Relay Under Mild Conditions

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(45)

Published: Sept. 22, 2023

The efficient depolymerization of polyesters under mild conditions remains a significant challenge. Herein, we demonstrate highly strategy for the degradation diverse array waste as low to 80 °C, 1 bar H2 . key success this transformation relied on initial transesterification macromolecular polyester into more degradable oligomeric fragments in presence CH3 OH and subsequent hydrogenation by use rationally designed quinaldine-based Ru complex. Controlled experiments preliminary mechanistic studies disclosed catalysts could be hydrogenated eventually active species, which has been confirmed X-ray diffraction analysis directly used catalyst hydrogenolysis polyester. strong viability high activity new species protic solvent were explained detail. Besides, crucial role promoting reaction efficiency during whole process was also elucidated. synthetic utility method further illustrated preparing 1,4-cyclohexanedimethanol (CHDM) from polyethylene terephthalate (PET).

Language: Английский

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Diverse Alkyl–Silyl Cross-Coupling via Homolysis of Unactivated C(sp³)–O Bonds with the Cooperation of Gold Nanoparticles and Amphoteric Zirconium Oxides

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(8), P. 4613 - 4625

Published: Feb. 20, 2023

Since C(sp3)–O bonds are a ubiquitous chemical motif in both natural and artificial organic molecules, the universal transformation of will be key technology for achieving carbon neutrality. We report herein that gold nanoparticles supported on amphoteric metal oxides, namely, ZrO2, efficiently generated alkyl radicals via homolysis unactivated bonds, which consequently promoted C(sp3)–Si bond formation to give diverse organosilicon compounds. A wide array esters ethers, either commercially available or easily synthesized from alcohols participated heterogeneous gold-catalyzed silylation by disilanes alkyl-, allyl-, benzyl-, allenyl silanes high yields. In addition, this novel reaction could applied upcycling polyesters, i.e., degradation polyesters synthesis organosilanes were realized concurrently unique catalysis nanoparticles. Mechanistic studies corroborated notion generation is involved coupling cooperation an acid–base pair ZrO2 responsible stable bonds. The reusability air tolerance catalysts as well simple, scalable, green system enabled practical

Language: Английский

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Depolymerization of Polyester Fibers with Dimethyl Carbonate-Aided Methanolysis

ACS Materials Au, Journal Year: 2024, Volume and Issue: 4(3), P. 335 - 345

Published: March 18, 2024

Polyester fibers, comprising mostly poly(ethylene terephthalate) with high crystalline content, represent the most commonly produced plastic for ubiquitous textiles, and approximately 60 million tons are manufactured annually worldwide. Considering social issues of mismanaged waste from used textile products, there is an urgent demand sustainable polyester fiber recycling methods. We developed a low-temperature, rapid, efficient depolymerization method fibers. By utilizing methanolysis dimethyl carbonate as trapping agent ethylene glycol, fibers products proceeded at 50 °C 2 h, affording terephthalate (DMT) in >90% yield. This strategy allowed us to depolymerize even practical textiles blended other selectively isolate DMT yields. was also applicable colored analytically pure isolated via decolorization processes.

Language: Английский

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Closed‐Loop Polymer‐to‐Polymer Upcycling of Waste Poly (Ethylene Terephthalate) into Biodegradable and Programmable Materials

ChemSusChem, Journal Year: 2024, Volume and Issue: 17(13)

Published: Feb. 27, 2024

Abstract Poly(ethylene terephthalate) (PET), extensively employed in bottles, film, and fiber manufacture, has generated persistent environmental contamination due to its non‐degradable nature. The resolution of this issue requires the conversion waste PET into valuable products, often achieved through depolymerization monomers. However, laborious purification procedures involved extraction monomers pose challenges constraints on complete utilization PET. Herein, a strategy is demonstrated for polymer‐to‐polymer upcycling high‐value biodegradable programmable materials named PEXT. This process involves reversible transesterifications dependent ester bonds, wherein commercially available X‐monomers from aliphatic diacids diols are introduced, utilizing existing industrial equipment utilization. PEXT features molecular structure, delivering tailored mechanical, thermal, biodegradation performance. Notably, exhibits superior mechanical performance, with maximal elongation at break 3419.2 % toughness 270.79 MJ m −3 . These characteristics make suitable numerous applications, including shape‐memory materials, transparent films, fracture‐resistant stretchable components. Significantly, allows closed‐loop recycling within specific analogs by reprograming or X‐monomers. not only offers cost‐effective advantages large‐scale advanced but also demonstrates enormous prospect conservation.

Language: Английский

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Alcoholysis of oxyphenylene-based super engineering plastics mediated by readily available bases

Polymer Journal, Journal Year: 2024, Volume and Issue: 56(4), P. 369 - 377

Published: Jan. 4, 2024

Language: Английский

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Depolymerization of PET with Ethanol by Homogeneous Iron Catalysts Applied for Exclusive Chemical Recycling of Cloth Waste

Industrial Chemistry and Materials, Journal Year: 2024, Volume and Issue: unknown

Published: Jan. 1, 2024

The acid-, base-free exclusive depolymerization of PET with ethanol catalyzed by FeCl 3 affording DET and EG, the selective from textile waste have been demonstrated.

Language: Английский

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Depolymerization of Polyesters by Transesterification with Ethanol Using (Cyclopentadienyl)titanium Trichlorides

Catalysts, Journal Year: 2023, Volume and Issue: 13(2), P. 421 - 421

Published: Feb. 16, 2023

Exclusive chemical conversions of polyesters [poly(ethylene adipate) (PEA), poly(butylene (PBA), poly(ethylene terephthalate) (PET), (PBT)] to the corresponding monomers (diethyl adipate, diethyl terephthalate, ethylene glycol, 1,4-butane diol) by transesterification with ethanol using Cp’TiCl3 (Cp’ = Cp, Cp*) catalyst have been demonstrated. The present acid-base-free depolymerizations exhibited completed (>99%) PET, PBT afford terephthalate and glycol or diol exclusively (selectivity >99%) without formation any other by-products in NMR spectra (150–170 °C, Ti 1.0, 2.0 mol%). resultant reaction mixture after depolymerization PBA via CpTiCl3 (1.0 mol%, 150 3 h), consisting adipate diol, was heated at °C vacuo for 24 h high molecular weight recycled unimodal distribution (Mn 11,800, Mw/Mn 1.6), strongly demonstrating a possibility one-pot (acid-base-free) closed-loop recycling.

Language: Английский

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Exclusive Catalytic Chemical Recycling, Upcycling of Polyesters

Kobunshi, Journal Year: 2025, Volume and Issue: 74(5), P. 217 - 219

Published: Jan. 1, 2025

Language: Английский

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Depolymerization of PET with n-Hexylamine, n-Octylamine, and 3-Amino-1-Propanol, Affording Terephthalamides

Catalysts, Journal Year: 2025, Volume and Issue: 15(2), P. 129 - 129

Published: Jan. 29, 2025

The chemical conversion of plastic waste has been considered an important subject in terms the circular economy, and recycling upcycling poly(ethylene terephthalate) (PET) one most subjects. In this study, depolymerization PET with n-hexylamine, n-octylamine, 3-amino-1-propanol explored presence Cp*TiCl3 (Cp* = C5Me5). reactions n-hexylamine n-octylamine at 130 °C afforded corresponding N,N′-di(n-alkyl) terephthalamides high yields (>90%), plays a role as catalyst to facilitate exclusive selectivity. reaction proceeded 100 even absence Ti catalyst, affording N,N′-bis(3-hydroxy) yields. A unique contrast demonstrated between by transesterification alcohol aminolysis; depolymerizations these amines without aid catalyst.

Language: Английский

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Efficient catalytic upcycling of polyester and polycarbonate plastics using NNN-based iron catalyst

Research Square (Research Square), Journal Year: 2025, Volume and Issue: unknown

Published: April 24, 2025

The development of efficient, eco-friendly recycling methods for mitigating the environmental impact polyester waste remains a significant challenge. Herein, we establish an efficient catalytic system based on NNN-based iron pincer catalyst, which can facilitate hydrogenative depolymerization plastics using two methods. first method is to depolymerize into ester monomers via methanolysis and subsequent transfer hydrogenation ammonia borane as hydrogen source obtain diol products under mild conditions. second use molecular direct hydrogenolysis plastic products. catalyst [Fe(NNHN)Cl₂]₂ demonstrates high efficiency in degradation polycarbonate plastics, including when from daily life raw materials.

Language: Английский

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