Reactions of Unsaturated Compounds

Kaminsky, Werner; Arndt, Michael; Bhm, L. L.; Vogt, Dominik Walter; Chauvin, Yves; Olivier, Hélène; Henkelmann, Jochem; Taube, Roswitha; Sylvester, Gerd; Mol, J.C.; Drent, Eite; Broekhoven, J. A. M. van; Budzelaar, Peter H. M.; Yoshimura, N.; Wilke, Günther; Eckerle, Anette

doi:10.1002/9783527619351.ch2c

Cited by 14 publications

(6 citation statements)

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“…The iPP/oxide nanocomposite masterbatches were prepared by in situ polymerization under the action of a metallocene/MAO system . The co‐catalyst MAO is reactive towards the hydroxyl groups present on the surface of the fillers; methane is evolved and covalent Al&bond;O bonds are formed . Further MAO will interact with the new surface and will be preferentially located on that surface, i.e.…”

Section: Resultsmentioning

confidence: 99%

“…Nanocomposites may be realized using various methods, including melt compounding, solution and dispersion blending or in situ polymerization . Melt compounding, where a mixture of polymer and filler is contacted above the glass transition temperature and mechanically mixed, often leads to an unsatisfactory dispersion on account of difficulties in sufficiently agitating the typically highly viscous polymer melts.…”

Section: Introductionmentioning

confidence: 99%

“…These oxidic nanofillers were chosen for reasons of modifying the dielectric properties of PP . It is known that only small amounts of nanofiller are necessary to observe a significant impact on mechanical, thermal or dielectric properties . A constraint of this research was to avoid the addition of dispersing agents or functionalized polyolefins as compatibilizers as normally used for polar fillers.…”

Section: Introductionmentioning

confidence: 99%

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Isotactic polypropylene metal oxide and silica nanocomposites by a two‐step process comprising in situ olefin polymerization and melt compounding

Käselau

Scheel

Petersson

et al. 2019

Polymer International

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Nanocomposites of isotactic polypropylene (iPP) with 0.5 wt% filler of MgO@Mg(OH)2 (35 nm) or silicon dioxide (20–60 nm) or barium titanate (50 nm) nanoparticles were obtained from melt compounding of filler masterbatches with commercial iPP. The masterbatches with 5 wt% nanofiller were prepared in an in situ polymerization procedure using a metallocene/methylaluminoxane (MAO) catalyst system that was supported on the respective oxides. The original agglomerates of the nanoparticles were broken up by treatment with dibutylmagnesium for MgO@Mg(OH)2, and with ultrasound in the presence of MAO for SiO2 and BaTiO3. The tacticity (98% mmmm) of the in situ formed PP was not influenced by the presence of the nanofillers. Scanning electron microscopy and energy‐dispersive X‐ray spectroscopy mapping show a fine dispersion of single particles and small clouds or clusters. The primary nanoparticles appear to be surrounded by polymer. The elongation at break was decreased to 50, 17 and 9% for MgO@Mg(OH)2), SiO2 and BaTiO3, respectively. After melt compounding with iPP, a homogeneous single‐particle distribution of the oxidic nanoparticles was found in the resulting composites with 0.5 wt% filler content. © 2019 Society of Chemical Industry

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Isotactic polypropylene metal oxide and silica nanocomposites by a two‐step process comprising in situ olefin polymerization and melt compounding

Käselau

Scheel

Petersson

et al. 2019

Polymer International

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“…Trifluoromethyl substitution ( 20 ) was also tolerated. Primary alkyl chloride ( 21 and 22 ) and bromide ( 23 ) substrates performed well, demonstrating remarkable selectivity of this catalyst for Si–Cl over C–halide activation and allowing further reactivity such as substitution and cross-coupling reactions. , In contrast to our previously published silyl-Negishi reaction, synthetically useful terminal alkenes ( 24 ) also progressed without incident. Aryl substitution such as pentafluoroaryl ( 25 ), biphenyl ( 26 ), and phenyl ether ( 27 ) substrates were well-tolerated.…”

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confidence: 84%

Palladium-Catalyzed Cross-Coupling of Monochlorosilanes and Grignard Reagents

2017

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Using a palladium catalyst supported by DrewPhos, the alkylation of monochlorosilanes with primary and secondary alkyl-magnesium halides is now possible. Arylation with sterically demanding aromatic magnesium halides is also enabled. This transformation overcomes the high bond strength of the Si–Cl bond (113 kcal/mol) and is a rare example of a transition-metal catalyzed process involving its activation. Due to the availability of both chlorosilanes and organomagnesium halide reagents, this method allows for the preparation of a wide range of alkyl and aryl silanes.

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“…Additionally, the design of catalysts can still offer access to new advanced materials via their ability to copolymerize olefins and/or enable further macromolecular engineering . Among the family of catalysts developed for the polymerization of conjugated dienes, rare-earth metal catalysts are attractive and have provided a large range of polymer microstructures and in particular cis -1,4 polydienes. − More specifically, multicomponent catalysts have been developed industrially to produce butadiene rubber with very high cis -1,4 contents. These catalysts are generally based on a soluble rare-earth salt combined with an alkylaluminum and a halogenating agent such as alkylaluminum halides. , Though highly efficient, the structure of the catalytically active species of these catalytic systems remains unknown.…”

Section: Introductionmentioning

confidence: 99%

Cationic Phenoxyimine Complexes of Yttrium: Synthesis, Characterization, and Living Polymerization of Isoprene

et al. 2022

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The phenoxyimine cationic complex [L 1 Y(CH 2 SiMe 2 Ph)-(THF) 3 ][BArF] (L 1 = (3-t Bu)-(O)−C 6 H 3 −CH�N-(2,6-i Pr-C 6 H 3 )) was prepared starting from the homoleptic [Y(CH 2 SiMe 2 Ph) 3 (THF) 2 ] yttrium complex and the phenoxyimine ligand HL 1 and the subsequent cationization by the anilinium borate salt. The resulting complex was characterized by different techniques such as elemental analysis, NMR ( 1 H, 13 C, and 89 Y), and more specifically by the 1 H-coupled 89 Y INEPT. The reactivity of the cationic complex toward isoprene polymerization was evaluated in the presence of trialkylaluminum. This catalyst enables the living cis-1,4 polymerization of isoprene selectively. The influence and the role played by alkylaluminum are discussed based on the screening of a set of aluminum reagents. By means of a computational mechanistic investigation performed at the DFT level, a cationic complex that accounts for the cis/trans/3,4 selectivities experimentally observed is identified. Additionally, the in silico speciation of complexes resulting from the precatalytic mixture revealed the formation of stable Y/Al heterobimetallic complexes. Finally, for comparison purposes, the cationic amidinate yttrium complex [L 2 Y(CH 2 SiMe 2 Ph)(THF) 3 ][B(C 6 F 5 ) 4 ] (L 2 = PhC(N-2,6-i Pr 2 C 6 H 3 ) 2 ) was synthesized and evaluated toward isoprene polymerization under similar conditions. This complex turned out to be active and selective toward the formation of 3,4-units.

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Reactions of Unsaturated Compounds

Cited by 14 publications

References 345 publications

Isotactic polypropylene metal oxide and silica nanocomposites by a two‐step process comprising in situ olefin polymerization and melt compounding

Isotactic polypropylene metal oxide and silica nanocomposites by a two‐step process comprising in situ olefin polymerization and melt compounding

Palladium-Catalyzed Cross-Coupling of Monochlorosilanes and Grignard Reagents

Cationic Phenoxyimine Complexes of Yttrium: Synthesis, Characterization, and Living Polymerization of Isoprene

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