Organoboron-mediated polymerizations

Chemical Society Reviews, Год журнала: 2024, Номер 53(7), С. 3384 - 3456

Опубликована: Янв. 1, 2024

The scientific community has witnessed extensive developments and applications of organoboron compounds as synthetic elements metal-free catalysts for the construction small molecules, macromolecules, functional materials over last two decades. This review highlights achievements organoboron-mediated polymerizations in past several decades alongside mechanisms underlying these transformations from standpoint polymerization mode. Emphasis is placed on free radical polymerization, Lewis pair ionic (cationic anionic) polyhomologation. Herein, alkylborane/O

Язык: Английский

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High Molar Mass Polycarbonates as Closed-Loop Recyclable Thermoplastics

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(12), С. 8381 - 8393

Опубликована: Март 14, 2024

Using carbon dioxide (CO2) to make recyclable thermoplastics could reduce greenhouse gas emissions associated with polymer manufacturing. CO2/cyclic epoxide ring-opening copolymerization (ROCOP) allows for >30 wt % of the polycarbonate derive from CO2; so far, field has largely focused on oligocarbonates. In contrast, efficient catalysts high molar mass polycarbonates are underinvestigated, and resulting thermoplastic structure–property relationships, processing, recycling need be elucidated. This work describes a new organometallic Mg(II)Co(II) catalyst that combines productivity, low loading tolerance, highest polymerization control yield number average molecular weight (Mn) values 4 130 kg mol–1, narrow, monomodal distributions. It is used in ROCOP CO2 bicyclic epoxides produce series samples, each Mn > 100 poly(cyclohexene carbonate) (PCHC), poly(vinyl-cyclohexene (PvCHC), poly(ethyl-cyclohexene (PeCHC, by hydrogenation PvCHC), poly(cyclopentene (PCPC). All these materials amorphous thermoplastics, glass transition temperatures (85 < Tg 126 °C, differential scanning calorimetry) thermal stability (Td 260 °C). The cyclic ring substituents mediate materials' chain entanglements, viscosity, temperatures. Specifically, PCPC was found have 10× lower entanglement (Me)n 100× zero-shear viscosity compared those PCHC, showing potential as future thermoplastic. polymers fully recyclable, either reprocessing or using highly selective depolymerizations CO2. shows fastest depolymerization rates, achieving an activity 2500 h–1 >99% selectivity cyclopentene oxide

Язык: Английский

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Synergistic effects of core–shell poly(ionic liquids)@ZIF-8 nanocomposites for enhancing additive-free CO2 conversion

Journal of Colloid and Interface Science, Год журнала: 2024, Номер 661, С. 1000 - 1010

Опубликована: Фев. 6, 2024

Язык: Английский

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Quantifying CO₂ Insertion Equilibria for Low-Pressure Propene Oxide and Carbon Dioxide Ring Opening Copolymerization Catalysts

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(15), С. 10451 - 10464

Опубликована: Апрель 8, 2024

While outstanding catalysts are known for the ring-opening copolymerization (ROCOP) of CO2 and propene oxide (PO), few reported at low pressure. Here, a new series Co(III)M(I) heterodinuclear compared. The Co(III)K(I) complex shows best activity (TOF = 1728 h–1) selectivity (>90% polymer, >99% CO2) is highly effective pressures (<10 bar). insertion prerate determining chemical equilibrium step. At pressures, concentration active catalyst depends on pressure; above 12 bar, its saturated, rates independent pressure, allowing constant to be quantified first time (Keq 1.27 M–1). A unified rate law, applicable under all operating conditions, presented. As proof potential, published data leading literature reinterpreted constants estimated, showing that this law applies other systems.

Язык: Английский

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Recent progress in CO2-based polyurethanes and polyureas

Progress in Polymer Science, Год журнала: 2023, Номер 149, С. 101780 - 101780

Опубликована: Дек. 29, 2023

Язык: Английский

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Metal-Free Synthesis of Biodegradable CO₂-Based Oligo(carbonate-ester) Diols as Building Blocks for Thermoplastic Polyurethanes

ACS Applied Polymer Materials, Год журнала: 2024, Номер 6(3), С. 1813 - 1822

Опубликована: Янв. 29, 2024

We for the first time synthesize a type of biodegradable CO2-based oligo(carbonate-ester) diol (PPCPDL) with aromatic ester units via one-pot immortal copolymerization using carbon dioxide (CO2)/propylene oxide (PO)/phthalic anhydride (PA) as raw materials and 1, 4-butanediol (BDO) proton exchange agent (PEA), respectively, catalyzed by metal-free triethylborane/triethylamine (TEB/TEA) Lewis pairs. A series PPCPDLs molar mass (Mn) ranging from 1100 to 7100 Da polyester content (PE mol %) between 0 36% were constructed tuning reaction temperature, CO2 pressure, time, feeding ratio. Our strategy adopts PA third monomer incorporate PE blocks into PPCPDLs, affording resulting thermoplastic polyurethanes (TPUs) improved thermal/mechanical properties. TPU-PPCPDL aliphatic carbonate- polyester-units can deliver highest tensile strength 35.2 MPa hardness 97 (Shore A), superior commercial diols-based TPUs. Twenty wt % propylene glycol (PPG) was also introduced second soft segment TPU-PPCPDLs endow obtained TPUs various physical properties, including good thermal stability, light transmittance, mechanical behaviors, which indirectly highlights application value significance such building in TPU production.

Язык: Английский

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From epoxides and carbon dioxide to polycarbonates: synthesis, properties and applications

Russian Chemical Reviews, Год журнала: 2024, Номер 93(2), С. RCR5112 - RCR5112

Опубликована: Янв. 16, 2024

Carbon dioxide (CO₂) plays a vital role in organic and polymer chemistry as source of cheap available raw material for the synthesis many valuable products, including materials with specified set properties, solvent chemical reactions. This review is devoted to synthesis, properties applications polycarbonates obtained by copolymerization CO₂ epoxides, hot topic that has aroused great interest among scientific community industry representatives. The existing data on catalytic systems used are analyzed summarized, depolymerization polycarbonates, which key aspect recycling, discussed, information systematized, prospects development this area considered.<br> Bibliography — 438 references.

Язык: Английский

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Bio-based polycarbonates: progress and prospects

RSC Sustainability, Год журнала: 2023, Номер 1(9), С. 2162 - 2179

Опубликована: Янв. 1, 2023

The review covers the advancements in bio-based polycarbonates with regards to their raw materials, polymerization techniques, and modification strategies.

Язык: Английский

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Facile and direct synthesis of oligocarbonate diols from carbon dioxide and their application as sustainable feedstock for polyurethane

Journal of CO2 Utilization, Год журнала: 2023, Номер 75, С. 102571 - 102571

Опубликована: Авг. 19, 2023

Oligocarbonate diols (PPCDL) with carbonate content higher than 90% were successfully synthesized by the direct copolymerization of propylene oxide (PO) and carbon dioxide (CO2) using metal-free Lewis acid-base catalysts in presence 1,4-butanediol (BDO) as proton exchange agent (PEA). The effects molar ratio PO to BDO, temperature, pressure reaction time on systematically investigated. molecular weight prepared oligocarbonate is good linear relationship PO/BDO feeding can be easily precisely controlled range 1000–4000 g mol−1. detailed structures fully investigated 1H NMR, 13C MALDI-TOF analysis. rheological properties PPCDL also studied a rheometer. Finally, polycarbonate urethanes designed PPCDLs soft segment 4,4′-diphenylmethane diisocyanate (MDI) BDO hard segment. comprehensive evaluation thermal mechanical poly(carbonate urethane)s (PCUs) demonstrates their complete feasibility application polyurethane industry.

Язык: Английский

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Organocatalyzed Copolymerization of CO ₂ with Epoxide Toward Polycarbonate Synthesis

Опубликована: Март 7, 2025

Язык: Английский

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