Synthesis, Characterization, and Catalytic Properties of Regioisomeric β‐Ketoimine Titanium Complexes for Ethylene Polymerization

Applied Organometallic Chemistry, Journal Year: 2025, Volume and Issue: 39(2)

Published: Jan. 1, 2025

ABSTRACT Non‐metallocene catalysts have shown great potential for modulating the polymer microstructure by changing ligand structure, but effects of structure and electronic property metal center on their catalytic performance remain underexplored. Herein, we designed synthesized two pairs isomeric tridentate β‐ketoimine complexes TiL a / b c d with methylthioaniline methylthioethylamine side arms, respectively, which exhibited moderate to extremely high activity over 10 6 g (mol Ti) −1 · h ·atm polymerization ethylene copolymerization α‐olefins (1‐hexene, 1‐octene) polar comonomer (9‐decen‐1‐ol) in presence MAO, activities order: > . The regioisomers arm showed significantly higher (co)polymerization than that arm, especially or 9‐decen‐1‐ol, indicating an obvious positive “comonomer effect”. complex highest insertion rate. Structural optimization using density functional theory (DFT) calculations suggested “side arms” properties titanium played key role copolymerization.

Language: Английский

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Ultrahigh Molecular Weight Ethylene–Acrylate Copolymers Synthesized with Highly Active Neutral Nickel Catalysts

Angewandte Chemie International Edition, Journal Year: 2025, Volume and Issue: unknown

Published: March 6, 2025

Molecular weight is a crucial parameter in catalytic olefin polymerization to determine the thermomechanical properties of polymers. Elevating molecular ethylene-acrylate copolymer, typical polar polyolefin has been persistent challenge. This study presents direct synthesis ultrahigh (UHMW) copolymers using highly active, neutral, single-component phosphine-phenolate nickel catalyst under mild conditions. The coordination-insertion copolymerization ethylene and various acrylates, such as methyl acrylate, n-butyl t-butyl can yield with UHMWs (Mn) ranging from 1000 2700 kDa, exceptional activities up 4.03 × 106 g mol-1 h-1. A relatively large-scale (30-50 g) UHMW was notably achieved. these were comprehensively evaluated, demonstrating that retained bulk polyethylene (UHMWPE) while exhibiting improved surface dyeing properties. In particular, tensile strength significantly increased higher weights, reaching 44 MPa (147 after predrawing ratio 3.1), which comparable UHMWPE.

Language: Английский

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Ultrahigh Molecular Weight Ethylene–Acrylate Copolymers Synthesized with Highly Active Neutral Nickel Catalysts

Angewandte Chemie, Journal Year: 2025, Volume and Issue: unknown

Published: March 6, 2025

Abstract Molecular weight is a crucial parameter in catalytic olefin polymerization to determine the thermomechanical properties of polymers. Elevating molecular ethylene–acrylate copolymer, typical polar polyolefin has been persistent challenge. This study presents direct synthesis ultrahigh (UHMW) copolymers using highly active, neutral, single‐component phosphine‐phenolate nickel catalyst under mild conditions. The coordination‐insertion copolymerization ethylene and various acrylates, such as methyl acrylate, n ‐butyl t can yield with UHMWs ( M ) ranging from 1000 2700 kDa, exceptional activities up 4.03 × 10 6 g mol −1 h . A relatively large‐scale (30–50 g) UHMW was notably achieved. these were comprehensively evaluated, demonstrating that retained bulk polyethylene (UHMWPE) while exhibiting improved surface dyeing properties. In particular, tensile strength significantly increased higher weights, reaching 44 MPa (147 after predrawing ratio 3.1), which comparable UHMWPE.

Language: Английский

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Nickel Catalyst With Excellent Thermal Stability for Ethylene Polymerization and Copolymerization

Applied Organometallic Chemistry, Journal Year: 2025, Volume and Issue: 39(3)

Published: Feb. 12, 2025

ABSTRACT Recently, a series of inexpensive nickel‐based phosphine phenol catalysts have been synthesized for catalyzing the copolymerization ethylene and polar monomers to prepare functionalized polyolefins. However, it is still challenging achieve homogeneous nickel that catalyze polymerization or at high temperatures (up 150°C) with activity. This work bulky steric hindrance electron donating groups, which were used coordination temperatures. These exhibited activity excellent thermal stability 150°C, producing polyethylene molecular weight up 102.7 × 10 4 g mol −1 . More importantly, these can range 120°C, improving surface properties

Language: Английский

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Design and Synthesis of Bis-β-ketoimine Binuclear Titanium Complex Isomers to Probe Bimetallic Synergistic Effect for Ethylene Polymerization

Chinese Journal of Polymer Science, Journal Year: 2025, Volume and Issue: unknown

Published: April 7, 2025

Language: Английский

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