Catalytic Upcycling of Polyolefins

Chemical Reviews, Journal Year: 2024, Volume and Issue: 124(16), P. 9457 - 9579

Published: Aug. 16, 2024

The large production volumes of commodity polyolefins (specifically, polyethylene, polypropylene, polystyrene, and poly(vinyl chloride)), in conjunction with their low unit values multitude short-term uses, have resulted a significant pressing waste management challenge. Only small fraction these is currently mechanically recycled, the rest being incinerated, accumulating landfills, or leaking into natural environment. Since are energy-rich materials, there considerable interest recouping some chemical value while simultaneously motivating more responsible end-of-life management. An emerging strategy catalytic depolymerization, which portion C-C bonds polyolefin backbone broken assistance catalyst and, cases, additional molecule reagents. When products molecules materials higher own right, as feedstocks, process called upcycling. This review summarizes recent progress for four major upcycling strategies: hydrogenolysis, (hydro)cracking, tandem processes involving metathesis, selective oxidation. Key considerations include macromolecular reaction mechanisms relative to mechanisms, design transformations, effect conditions on product selectivity. Metrics describing critically evaluated, an outlook future advances described.

Language: Английский

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Unlocking naphtha from polyolefins using Ni-based hydrocracking catalysts

Chemical Engineering Journal, Journal Year: 2024, Volume and Issue: 487, P. 150468 - 150468

Published: March 15, 2024

Language: Английский

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Catalytic and engineering strategies for enhanced hydrogenation reactions: A review of heterogeneous catalysts and process optimization

Results in Engineering, Journal Year: 2025, Volume and Issue: unknown, P. 103958 - 103958

Published: Jan. 1, 2025

Language: Английский

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Co-upcycling of polyethylene terephthalate and polyoxymethylene into valuable chemicals

Chem Catalysis, Journal Year: 2025, Volume and Issue: unknown, P. 101232 - 101232

Published: Jan. 1, 2025

Language: Английский

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Coupled conversion of polyethylene and carbon dioxide catalyzed by a zeolite–metal oxide system

Science Advances, Journal Year: 2024, Volume and Issue: 10(15)

Published: April 12, 2024

Zeolite-catalyzed polyethylene (PE) aromatization achieves reduction of the aromatic yield via hydrogenation and hydrogenolysis reactions. The hydrogen required for CO 2 can be provided by H radicals formed during aromatization. In this study, we efficiently convert PE into aromatics using a zeolite–metal oxide catalyst (HZSM-5 + CuZnZrO x ) at 380°C under hydrogen- solvent-free reaction conditions. Hydrogen, derived from over HZSM-5, diffuses through Brønsted acidic sites zeolite to adjacent , where it is captured in situ produce bicarbonate further hydrogenated CO. This favors while inhibiting secondary An 62.5 wt % achieved, which 60% consisted benzene, toluene, xylene (BTX). conversion reaches values as high 0.55 mmol g −1 . aromatization–hydrogen capture pathway provides feasible scheme comprehensive utilization waste plastics

Language: Английский

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Hierarchical FAU Zeolites Boosting the Hydrocracking of Polyolefin Waste into Liquid Fuels

ACS Sustainable Chemistry & Engineering, Journal Year: 2024, Volume and Issue: 12(15), P. 6013 - 6022

Published: April 3, 2024

Conventional metal-zeolite catalysts struggle with hydrocracking polyolefin wastes due to a significant mismatch between the size of large polymer molecules and micropores zeolites. This severely constrains diffusion site accessibility, resulting in low efficiency. Here, we unveil simple hydrothermal treatment commercial Y zeolite that creates hierarchical (Y–H), which possesses substantial layers mesoporous nanoflakes on its surface, constructing unique pore architecture. network integrates (ca. 13 nm) medium 4 mesopores original (<1 critically without altering zeolite's topology, crystallinity, or acidity. Compared Pt/Al2O3, Y–H Pt/Al2O3 exhibit remarkable 4-fold increase activity, is attributed enhanced accessibility acid sites, providing sufficient cascade cracking space for macromolecular polyolefins be efficiently converted into small, branched alkanes. Notably, catalyst achieves an impressive 96.8% PE conversion 90.8% selectivity toward value-added gasoline diesel fuels (C5–20) within h at 280 °C. work not only demonstrates pivotal role networks but also highlights their broader applicability plastic waste upcycling.

Language: Английский

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Catalytic chemical recycling and upcycling of polyolefin plastics

Giant, Journal Year: 2024, Volume and Issue: 19, P. 100307 - 100307

Published: June 14, 2024

Polyolefins are the most produced and widely used polymeric materials. However, chemically inert nature of polyolefins has led to severe environmental pollution, posing a threat human sustenance development. Managing recycling polyolefin plastic waste is crucial for transition from linear sustainable circular economy. Catalytic chemical includes traditional techniques like pyrolysis photolysis, innovative methods that introduce cleavable bonds into chain closed-loop recycling. post-functionalization post-consumer materials another strategy tackle waste, aiming upgrade materials' utility contribute sustainability. Overall, developing catalytic deconstructing upcycling plastics essential encourage better reclamation practices reduce impact waste.

Language: Английский

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Improving hydrogen production via ex-situ catalytic fast pyrolysis of non-thermal plasma pretreated HDPE with 1Fe1Ni/γ-Al2O3 catalyst

Applied Catalysis B Environment and Energy, Journal Year: 2025, Volume and Issue: unknown, P. 125129 - 125129

Published: Feb. 1, 2025

Language: Английский

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Persulfate-Based Advanced Oxidation Reforming of Polyethylene Terephthalate Fiber into Formate via Singlet Oxygen Activation

Advanced Fiber Materials, Journal Year: 2025, Volume and Issue: unknown

Published: March 10, 2025

Language: Английский

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Polystyrene Hydrogenolysis to High-Quality Lubricants Using Ni/SiO₂

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(7), P. 5389 - 5402

Published: March 27, 2024

Pyrolytic and light-activated oxidation processes are leading technologies for utilizing polystyrene (PS) wastes. These approaches exhibit poor selectivities, use complex reactors, require solvents. Hydrogenolysis is effective deconstructing polyolefins, but its application to PS feedstocks has been limited. Herein, we demonstrate Ni/SiO2 catalysts facilitate (Mw ≈ 97 kDa) hydrogenolysis produce lubricant base oils possessing group IV properties, achieving maximum yields of 70% within 6 h at 300 °C 70 bar H2. Gas, liquid, oil product stable across reaction conditions, whereas hydrogenation the aromaticity reduction molecular weight benefit from higher temperatures H2 pressures. Time-dependent experiments underscore importance elevated pressure, revealing that occurs sequentially, with aromatic ring preceding degradation C–C backbone. Kinetic measurements 1,2-diphenylethane as a probe molecule pis 3 orders magnitude faster than internal bond cleavage over Ni/SiO2. proves be in heavier polymers rigid commercial products. Conversely, flexibility foam feeds result deactivation, attributed performance additives. Unlike process produces very little methane other light hydrocarbons. findings expand applicability feedstocks, offering versatile solution broadening range high-value products include oils.

Language: Английский

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