Rapid Polyolefin Plastic Hydrogenolysis Mediated by Single-Site Heterogeneous Electrophilic/Cationic Organo-group IV Catalysts DOI

Wilson C. Edenfield,

Alexander H. Mason, Qingheng Lai

et al.

ACS Catalysis, Journal Year: 2023, Volume and Issue: 14(1), P. 554 - 565

Published: Dec. 26, 2023

A homologous series of cationic electrophilic group IV metal hydrides (M = Ti, Zr, Hf) created by chemisorption the corresponding MNp4 precursors on highly Brønsted acidic sulfated alumina (AlS) to yield loosely coordinated surface AlS/MNp2 (Np neopentyl) species are systematically characterized ICP, EXAFS/XANES, DRIFTS, and solid-state high-resolution multidimensional NMR spectroscopy (SSNMR), as well energy span DFT computation. With effective stirring, these complexes readily undergo reaction with H2 AlS/M(alkyl)H species, which active for hydrogenolysis diverse commercial polyethylenes, α-olefin-ethylene copolymers, isotactic polypropylene, postconsumer polyolefins including high-density yielding medium small linear branched hydrocarbons at turnover frequencies high 36,300 h–1 200 °C/17 atm M Zr. For given polyolefin conditions, scale approximately Zr > Hf whereas catalyst thermal stability scales ≈ trends qualitatively understandable from analysis. These catalytic results reveal that AlS/Hf(R)H-mediated favors wax-like liquid products, AlS/Zr(R)H-mediated can be tuned between gases liquids. analysis identifies β-alkyl elimination turnover-limiting C–C scission process, is particularly facile in d0 but not so neutrally charged analogues.

Language: Английский

Temperature-Dependent NiFeAl catalysts for efficient microwave-assisted catalytic pyrolysis of polyethylene into value-added hydrogen and carbon nanotubes DOI
Zhe Zhang, Huan Chen,

Wenheng Hu

et al.

Fuel, Journal Year: 2024, Volume and Issue: 366, P. 131390 - 131390

Published: March 5, 2024

Language: Английский

Citations

4
Mild Catalytic Degradation of Crystalline Polyethylene Units in a Solid State Assisted by Carboxylic Acid Groups DOI
Bin Lü, Kohei Takahashi, Jian Zhou

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(28), P. 19599 - 19608

Published: July 2, 2024

Crystalline polyethylenes bearing carboxylic acid groups in the main chain were successfully degraded with a Ce catalyst and visible light. The reaction proceeds crystalline solid state without swelling acetonitrile or water at temperature as low 60 80 °C, employing dioxygen air only stoichiometric reactant nearly quantitative recovery of carbon atoms. Heterogeneous features allowed us to reveal dynamic morphological change polymer crystals during degradation.

Language: Английский

Citations

4
Pyrolytic Depolymerization of Polyolefins Catalyzed by Zirconium‐based UiO‐66 Metal‐Organic Frameworks DOI Open Access
Jerry Zhi Xiong Heng, Tristan Tsai Yuan Tan, Xin Li

et al.

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(44)

Published: Aug. 1, 2024

Abstract Polyolefins such as polyethylenes and polypropylenes are the most‐produced plastic waste globally, yet difficult to convert into useful products due their unreactivity. Pyrolysis is a practical method for large‐scale treatment of mixed, contaminated plastic, allowing conversion industrially‐relevant petrochemicals. Metal–organic frameworks (MOFs), despite tremendous utility in heterogeneous catalysis, have been overlooked polyolefin depolymerization perceived thermal instabilities inability penetrate pores. Herein, we demonstrate viability UiO‐66 MOFs containing coordinatively‐unsaturated zirconium nodes, effective catalysts pyrolysis that significantly enhances yields valuable liquid gas hydrocarbons, whilst halving amounts residual solids produced. Reactions occur on Lewis‐acidic without need noble metals, yield aliphatic product distributions distinctly different from aromatic‐rich hydrocarbons can be obtained zeolite catalysis. We also first unambiguous characterization penetration pores at pyrolytic temperatures, access abundant Zr‐oxo nodes within MOF interior efficient C−C cleavage. Our work highlights potential highly‐designable depolymerisation plastics, which complement conventional reactivity.

Language: Английский

Citations

4
Microwave‐Powered Liquid Metal Degradation of Polyolefins DOI Open Access
Jianye Gao,

Jun Zhao,

Zerong Xing

et al.

Advanced Materials, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 18, 2024

Abstract Upcycling waste plastics is highly promising to tackle global white pollution while achieving sustainable development. However, prevailing approaches often encounter challenges in scalable engineering practices due either insufficient plastic upcycling capability or arduousness the separation, recovery, and purification of catalysts, which inevitably augments cost upcycling. Here, microwave‐powered liquid metal synergetic depolymerization presented facilitate low‐cost By leveraging fluidity metals their exceptional chemical‐bond activation ability under microwave field, this method efficiently converts various polyolefins into narrowband hydrocarbon oil (Oil yield: 81 wt.% for polypropylene (PP), 85.9 polyethylene (PE)) high‐value olefin monomers (C 2‐4  selectivity: 50% PE, 65.3% PP) over 30 successive cycles, resulting a high turnover frequency 2.83 kg Plastic mL Liquid −1 . These captivating advantages offered by electromagnetically‐powered are also supported self‐separation features, thereby paving way large‐scale solutions

Language: Английский

Citations

4
Rapid Polyolefin Plastic Hydrogenolysis Mediated by Single-Site Heterogeneous Electrophilic/Cationic Organo-group IV Catalysts DOI

Wilson C. Edenfield,

Alexander H. Mason, Qingheng Lai

et al.

ACS Catalysis, Journal Year: 2023, Volume and Issue: 14(1), P. 554 - 565

Published: Dec. 26, 2023

A homologous series of cationic electrophilic group IV metal hydrides (M = Ti, Zr, Hf) created by chemisorption the corresponding MNp4 precursors on highly Brønsted acidic sulfated alumina (AlS) to yield loosely coordinated surface AlS/MNp2 (Np neopentyl) species are systematically characterized ICP, EXAFS/XANES, DRIFTS, and solid-state high-resolution multidimensional NMR spectroscopy (SSNMR), as well energy span DFT computation. With effective stirring, these complexes readily undergo reaction with H2 AlS/M(alkyl)H species, which active for hydrogenolysis diverse commercial polyethylenes, α-olefin-ethylene copolymers, isotactic polypropylene, postconsumer polyolefins including high-density yielding medium small linear branched hydrocarbons at turnover frequencies high 36,300 h–1 200 °C/17 atm M Zr. For given polyolefin conditions, scale approximately Zr > Hf whereas catalyst thermal stability scales ≈ trends qualitatively understandable from analysis. These catalytic results reveal that AlS/Hf(R)H-mediated favors wax-like liquid products, AlS/Zr(R)H-mediated can be tuned between gases liquids. analysis identifies β-alkyl elimination turnover-limiting C–C scission process, is particularly facile in d0 but not so neutrally charged analogues.

Language: Английский

Citations

10