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

---

Characterization of polymer properties and identification of additives in commercially available research plastics

Green Chemistry, Journal Year: 2024, Volume and Issue: 26(12), P. 7067 - 7090

Published: Jan. 1, 2024

This work reports the analysis of 59 commercially available polymers from 20 different polymer classes for thermal properties, macrostructure, molecular mass distribution, and inorganic organic additives, highlighting need to characterize research prior recycling studies.

Language: Английский

---

Hydrodeoxygenation of Oxygen‐Containing Aromatic Plastic Wastes to Liquid Organic Hydrogen Carriers

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(46)

Published: Aug. 3, 2023

To address the global plastic pollution issues and challenges of hydrogen storage transportation, we report a system, based on hydrodeoxygenation (HDO) oxygen-containing aromatic wastes, from which organic carriers (LOHCs) can be derived. We developed catalytic system comprised Ru-ReOx /SiO2 +HZSM-5 for direct HDO polycarbonate (PC), polyethylene terephthalate (PET), polybutylene (PBT), polyphenylene oxide (PPO), their mixtures, to cycloalkanes as LOHCs, with high yields up 99 %, under mild reaction conditions. The theoretical capacity reaches ca. 5.74 wt%. pathway involves depolymerization PC into C15 aromatics monophenols by hydrogenolysis C-O bond between benzene ring ester group, subsequent parallel hydrogenation monophenols. cyclic alcohol is rate-determining step. active site Ru metallic nanoparticles partially covered ReOx species. excellent performance attributed synergetic effect oxophilic species sites hydrogenation, promotion HZSM-5 dehydration alcohol. highly efficient stable dehydrogenation over Pt/γ-Al2 O3 confirms that products act LOHCs.

Language: Английский

---

SMSI-induced charge transfer for selective hydrogenolysis of polyolefins

Applied Catalysis B Environment and Energy, Journal Year: 2023, Volume and Issue: 339, P. 123122 - 123122

Published: July 23, 2023

Language: Английский

---

Entropy Confinement Promotes Hydrogenolysis Activity for Polyethylene Upcycling

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(47)

Published: Oct. 6, 2023

Chemical upcycling that catalyzes waste plastics back to high-purity chemicals holds great promise in end-of-life valorization. One of the main challenges this process is thermodynamic limitations imposed by high intrinsic entropy polymer chains, which makes their adsorption on catalysts unfavorable and transition state unstable. Here, we overcome challenge inducing catalytic reaction inside mesoporous channels, possess a strong confined ability allowing for stabilization state. This approach involves synthesis p-Ru/SBA catalysts, Ru nanoparticles are uniformly distributed within channels an SBA-15 support, using precise impregnation method. The unique design catalyst has demonstrated significant improvements performance conversion polyethylene into high-value liquid fuels, particularly diesel. achieved solid rate 1106 g ⋅ gRu-1 h-1 at 230 °C. Comparatively, activity 4.9 times higher than control catalyst, Ru/SiO2 , 14.0 commercial Ru/C, 240 remarkable opens up immense opportunities chemical plastics.

Language: Английский

---

Boosting Polyethylene Hydrogenolysis Performance of Ru‐CeO₂ Catalysts by Finely Regulating the Ru Sizes

Small, Journal Year: 2023, Volume and Issue: 19(35)

Published: April 25, 2023

Hydrogenolysis is an effective method for converting polyolefins into high-value chemicals. For the supported catalysts commonly used, size of active metals great importance. In this study, it discovered that activity CeO2 -supported Ru single atom, nanocluster, and nanoparticle shows a volcanic trend in low-density polyethylene (LDPE) hydrogenolysis. Compared with atoms nanoparticles, nanoclusters possess highest conversion efficiency, as well best selectivity toward liquid alkanes. Through comprehensive investigations, metal-support interactions (MSI) hydrogen spillover effect are revealed two key factors reaction. On one hand, MSI strongly related to surface states more electronegative centers beneficial activation CH CC bonds. other capability directly affects affinity H atoms, increasing advantageous hydrogenation alkane species. Decreasing sizes can promote MSI, but also reduce effect. Therefore, only when effects achieve balance, case nanoclusters, hydrogenolysis be promoted optimal value.

Language: Английский

---

Ni/HZSM-5 catalysts for hydrodeoxygenation of polycarbonate plastic wastes into cycloalkanes for sustainable aviation fuels

Applied Catalysis B Environment and Energy, Journal Year: 2023, Volume and Issue: 338, P. 123050 - 123050

Published: July 1, 2023

Language: Английский

---

Catalytic Hydrogenolysis of Polyethylene Under Reactive Separation

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(3), P. 2084 - 2094

Published: Jan. 24, 2024

Deconstruction of polyolefins by catalytic hydrogenolysis is typically accompanied the generation undesired light gases. At reaction temperatures, desired liquid products also tend to be volatile. Secondary cleavage these contributes gas formation. The latter process was mitigated reactive separation, continuously separating from catalyst throughout experiment. equivalent conversion, yield and selectivity for oligomeric species are increased under even though carbon–carbon bond rate slower than that in sealed experiments. More formed reactor. Under 1 atm H2 partial pressure, alkenes accompany typical alkane products. alkene higher, with greater valuable α-olefins separation. These results provide mechanistic insight terminal primary during experimental conditions, secondary deconstruction produces

Language: Английский

---

Perspectives on sustainable plastic treatment: A shift from linear to circular economy

TrAC Trends in Analytical Chemistry, Journal Year: 2024, Volume and Issue: 173, P. 117631 - 117631

Published: March 5, 2024

The pervasive presence of plastics in the environment, particularly microplastics, has become a significant global challenge, demanding innovative solutions for their management and upcycling. While traditional methods including landfill incineration face limitations environmental impact, emerging technologies offer promising pathways conversion into valuable chemicals fuels, operating under ambient conditions often utilizing sustainable energy sources. Considering current research progress plastic upgrading, it is necessary to summarize chemical upcycling waste. To this end, review provides an overall examination methodologies treatment, pyrolysis, hydrogenolysis, photocatalysis, electrocatalysis. Existing knowledge gaps future directions are then proposed. Overall, highlights potential these novel approaches aligning with principles circular economy.

Language: Английский

---

Chemical Upcycling of Polyolefin Plastics Using Structurally Well-defined Catalysts

JACS Au, Journal Year: 2024, Volume and Issue: 4(6), P. 2081 - 2098

Published: June 4, 2024

Single-use polyolefins are widely used in our daily life and industrial production due to their light weight, low cost, superior stability, durability. However, the rapid accumulation of plastic waste low-profit recycling methods resulted a global crisis. Catalytic hydrogenolysis is regarded as promising technique, which can effectively selectively convert polyolefin value-added products. In this perspective, we focus on design synthesis structurally well-defined catalysts across mesoscopic, nanoscopic, atomic scales, accompanied by insights into future directions catalyst for further enhancing catalytic performance. These principles also be applied depolymerization other polymers ultimately realize chemical upcycling plastics.

Language: Английский

---