Mechanism-Inspired Upgradation of Phosphonium-Containing Organoboron Catalysts for Epoxide-Involved Copolymerization and Homopolymerization

Macromolecules, Год журнала: 2022, Номер 55(15), С. 6443 - 6452

Опубликована: Июль 14, 2022

The dynamic Lewis multicore system (DLMCS) which integrates the acidic boron center(s) and an ammonium salt in one molecule has shown good catalytic performance polymer synthesis. Inspired by insightful intramolecular cation assisted mechanism, herein, we communicated a superior organoboron replacing nitrogen atom with phosphorus atom. upgraded mono-, di-, trinuclear catalysts show significantly improved heat resistance for versatile epoxide-involved transformations, including ring-opening copolymerization of epoxides cyclic anhydrides, CO2 epoxides, polymerization epoxides. 11B NMR, single-crystal X-ray diffraction, DFT results imply that onium led to effective epoxide activation nucleophilic attack counterion on activated epoxide, remarkably shortened initiation period accelerated chain expansion, resulting obvious improvement activity. phosphonium-containing combined mechanism study understanding would be instructive designing advanced metal-free catalysts.

Язык: Английский

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Highly Selective Preparation and Depolymerization of Chemically Recyclable Poly(cyclopentene carbonate) Enabled by Organoboron Catalysts

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(46)

Опубликована: Сен. 22, 2022

Poly(cyclopentene carbonate) (PCPC) produced by copolymerization of CO2 and cyclopentene oxide (CPO) is a promising but challenging chemical recyclable polymer that has high potential in minimizing plastic pollution maximizing utilization. Currently, problems remain to be solved, include low reactivity toxic metal catalysts, inevitable byproducts, especially the ambiguous mechanism understanding. Herein, we present first metal-free access PCPC using series modular dinuclear organoboron catalysts. was afforded an unprecedented catalytic efficiency 1.0 kg PCPC/g catalyst; while depolymerization abides combination pathway random chain scission unzipping, returning CPO near-quantitative yield (>99 %). The preparation along with depth understanding related mechanisms would helpful for further development advanced catalysts plastics.

Язык: Английский

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Emerging Trends in Closed‐Loop Recycling Polymers: Monomer Design and Catalytic Bulk Depolymerization

Chemistry - A European Journal, Год журнала: 2023, Номер 29(23)

Опубликована: Фев. 4, 2023

Plastics are indispensable materials in modern society; however, their extensive use has contributed to the depletion of finite natural resources and caused severe environmental issues. One end-of-use solution for plastics involves chemical recycling polymers back monomers repolymerization virgin without changing material properties, allowing establishment a circular economy. This concept focuses on critical advantages chemically recyclable terms monomer design, feasibility bulk depolymerization. The recyclability via thermolysis various polyesters, CO2 -based polycarbonates, polyacetals produced ring-opening polymerization is highlighted through discussions regarding rational design efficient catalyst development. An outlook perspective provided delineate future challenges polymer structures that deliver desired performance while being suitable with high (de)polymerization activity selectivity.

Язык: Английский

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Borane catalysis for epoxide (co)polymerization

Polymer Chemistry, Год журнала: 2023, Номер 14(16), С. 1834 - 1862

Опубликована: Янв. 1, 2023

This review discusses the impact of borane catalysis on epoxide homo- and copolymerization, focussing polymerization mechanisms catalyst design.

Язык: Английский

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Ultra-Productive Upcycling CO₂ into Polycarbonate Polyols via Borinane-Based Bifunctional Organocatalysts

Macromolecules, Год журнала: 2023, Номер 56(3), С. 892 - 898

Опубликована: Янв. 23, 2023

We herein report the synthesis of commercially attractive low molar mass polycarbonate polyols obtained through ring-opening copolymerization CO2 and epoxides, using a series borinane-based bifunctional organocatalysts in presence chain transfer agents (CTAs). These catalysts enable CO2/epoxide copolymerizations with high linear vs cyclic selectivity outstanding productivity for both poly(cyclohexane carbonate) (18.2 kg/g catalyst) poly(ether propylene (1.1 catalyst). exhibit all features living processes; resulting polycarbonates could be precisely controlled by varying [monomer]/CTA ratio. The performance these implying loading shows great potential applications large-scale preparation CO2-based polyols.

Язык: Английский

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Advances in the Synthesis of Chemically Recyclable Polymers

Chemistry - An Asian Journal, Год журнала: 2023, Номер 18(3)

Опубликована: Янв. 9, 2023

Abstract The development of modern society is closely related to polymer materials. However, the accumulation materials and their evolution in environment causes not only serious environmental problems, but also waste resources. Although physical processing can be used reuse polymers, properties resulting polymers are significantly degraded. Chemically recyclable a type that degrades into monomers, an effective solution degradation caused by recycling polymers. ideal chemical i. e., quantitative conversion monomers at low energy consumption repolymerization formed with comparable original, attractive research goal. In recent years, significant progress has been made design enabling regulation “polymerization‐depolymerization” equilibrium closed‐loop under mild conditions. This review will focus on following aspects poly(sulfur) esters, polycarbonates, polyacetals, polyolefins, poly(disulfide) polymer, illustrate challenges this area, provide outlook future directions.

Язык: Английский

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Understanding catalytic synergy in dinuclear polymerization catalysts for sustainable polymers

Nature Communications, Год журнала: 2023, Номер 14(1)

Опубликована: Авг. 8, 2023

Abstract Understanding the chemistry underpinning intermetallic synergy and discovery of generally applicable structure-performances relationships are major challenges in catalysis. Additionally, high-performance catalysts using earth-abundant, non-toxic inexpensive elements must be prioritised. Here, a series heterodinuclear form Co(III)M(I/II), where M(I/II) = Na(I), K(I), Ca(II), Sr(II), Ba(II) evaluated for three different polymerizations, by assessment rate constants, turn over frequencies, polymer selectivity control. This allows comparisons performances both within between containing Group I II metals CO 2 /propene oxide ring-opening copolymerization (ROCOP), propene oxide/phthalic anhydride ROCOP lactide polymerization (ROP). The data reveal new structure-performance correlations that apply across all polymerizations: featuring s-block lower Lewis acidity show higher rates selectivity. epoxide/heterocumulene ROCOPs exponential activity increases (vs. acidity, measured p K [M(OH ) m ] n+ ), whilst ROP /epoxide linear increases. Such clear structure-activity/selectivity very unusual, yet fully rationalised mechanisms catalytic intermediates. general applicability polymerizations is significant future exploitation provides framework to improve other catalysts.

Язык: Английский

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Multifunctional Zn-N4 Catalysts for the Coupling of CO₂ with Epoxides into Cyclic Carbonates

ACS Catalysis, Год журнала: 2023, Номер 13(15), С. 10386 - 10393

Опубликована: Июль 25, 2023

The catalytic conversion of greenhouse gas CO2 into valuable chemicals is a vital goal toward carbon balance and sustainability. In recent decades, the chemical fixation cyclic carbonates has gained much attention. this work, series zinc complexes bearing tetradentate aminopyridine (N4) ligands have been synthesized characterized. These were applied to coupling with epoxides in excellent yields broad substrate scope under cocatalyst- solvent-free conditions. Moreover, catalysts could be readily recovered reused five times without an obvious loss activity. Based on spectroscopic characterizations experimental results, catalyst Zn-3 (DAP-ZnBr2, DAP = 1,4-bis(2-pyridymethyl)-1,4-diazepane) found multifunctional because presence Lewis acidic center nuclephilic halide anion, one pyridine released for activation during reaction.

Язык: Английский

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Synthesis of Sequence‐specific Poly(ester‐carbonate) Copolymers via Chemoselective Terpolymerization Controlled by the Stoichiometric Ratio of Phosphazene/Triethylborane

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(25)

Опубликована: Апрель 19, 2023

Abstract Chemoselective terpolymerization can produce polymer materials with diverse compositions and sequential structures, thus have attracted considerable attention in the field of synthesis. However, intrinsic complexity three‐component system also brings great chanllenge, regard to reactivity selectivity different monomers. Herein, we report CO 2 /epoxide/anhydride by a binary organocatalytic C 3 N ‐Py‐P /TEB (triethylborane) system. Both activity chemoselectivity were highly dependent upon molar ratio TEB, sequence‐controlled poly(ester‐carbonate) copolymers readily synthesized through one‐pot/one‐step methodology tuning stoichiometric phosphazene/TEB. In particular, 1/0.5 exhibited an unprecedentedly high for ring‐opening alternating copolymerization (ROAC) cyclohexene oxide (CHO) phthalic anhydride (PA) first then ROAC /CHO. Thus, well‐defined triblock polycarbonate‐ b ‐polyester‐ ‐polycarbonate be produced from mixture , CHO PA using bifunctional initiator. With /TEB=1/1, tapered obtained, while random content polycarbonate (PC) further increasing amount TEB. The mechanism unexpected was investigated DFT calculations.

Язык: Английский

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Coordination complexes as catalysts for the coupling reactions of oxiranes and carbon dioxide

Coordination Chemistry Reviews, Год журнала: 2023, Номер 492, С. 215277 - 215277

Опубликована: Июнь 10, 2023

Язык: Английский

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