Silanolytic Chain Transfer in Olefin Polymerization with Supported Single-Site Ziegler−Natta Catalysts

Makio, Haruyuki; Koo, Kwangmo; Marks, Tobin J.

doi:10.1021/ma010082r

Cited by 27 publications

(9 citation statements)

References 9 publications

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“…17 Me 2 SiCl 2 end-capped the growing polymer chains following an in-situ ( n BuCp) 2 ZrCl 2 -mediated catalytic cycle that presumably proceeds through concerted bond cleavage and formation via four-centered r-bond metathesis transition states. [83][84][85] See the postulated Scheme 4, which is supported by references cited in this context. This work mentions a case of potential activation of Si2Cl bond thru rbond metathesis using a chlorosilane, particularly applicable to ethylene2a-olefin copolymerization.…”

Section: Polymer Molecular Weight and Chain Transfer Effectsupporting

confidence: 62%

“…Route D: Silanolytic chain transfer in the presence of Me 2 SiCl 2 that simultaneously controls molecular weight and makes silyl-terminated polyethylene backbone. 83,84 The first three routes, with the concerned kinetic rate expressions, have been schematically detailed in one of our recent publications. 17 In pseudo-homogeneous polymerization, Me 2 SiCl 2 -a silane Lewis acid (electron-pair acceptor) with reactive labile Cl ligand-is freely available in the polymerization medium.…”

Section: Polymer Molecular Weight and Chain Transfer Effectmentioning

confidence: 99%

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(ⁿBuCp)₂ZrCl₂‐catalyzed ethylene‐4M1P copolymerization: Copolymer backbone structure, melt behavior, and crystallization

et al. 2016

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The judicious design of methylaluminoxane (MAO) anions expands the scope for developing industrial metallocene catalysts. Therefore, the effects of MAO anion design on the backbone structure, melt behavior, and crystallization of ethylene24-methyl-1-pentene (E24M1P) copolymer were investigated. Ethylene was homopolymerized, as well as copolymerized with 4M1P, using (1) , opposite to the supported analogue, acted as a co-chain transfer agent with 4M1P. The modeling of polyethylene melting and crystallization kinetics, including critical crystallite stability, produced insightful results. This study especially illustrates how branched polyethylene can be prepared from ethylene alone using particularly one metallocene-MAO ion pair, and how a compound, that functionalizes silica as well as terminates the chain, can synthesize ethylene2a-olefin copolymers with novel structures. Hence, it unfolds prospective future research niches in polyethyne systhesis.

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Section: Polymer Molecular Weight and Chain Transfer Effectsupporting

confidence: 62%

Section: Polymer Molecular Weight and Chain Transfer Effectmentioning

confidence: 99%

(ⁿBuCp)₂ZrCl₂‐catalyzed ethylene‐4M1P copolymerization: Copolymer backbone structure, melt behavior, and crystallization

et al. 2016

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“…The presence of silane functionalities during polymerization is not always desirable since silanes are known to be effective chain-transfer agents. 28 The selectivity of both anchoring the fluorene ligand to the silsesquioxane support and introduction of the zirconium is moderate. For silsesquioxanes this synthetic strategy is convenient only because the silsesquioxane-bonded ancillary ligand and the metal complexes thereof can be purified reasonably easy.…”

Section: Discussionmentioning

confidence: 99%

Silsesquioxane-bonded zirconocene complexes; soluble models for silica-tethered olefin polymerization catalysts

et al. 2003

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Silsesquioxane tethered fluorene ligands [R 7 Si 8 O 12 X]-9-Flu(H) (R = c-C 6 H 11 , X = -( 1 and [(c-C 5 H 9 ) 7 Si 8 O 12 CH 2 -9-Flu] 2 ZrCl 2 (9) have been applied as models for silicatethered ancillary ligands and silica tethered-zirconocenes. Immobilization of zirconocenes containing a pendant anchorable functionality, CpЉ[Me 2 (EtO)SiCH 2 Flu]ZrCl 2 (10) and Cp[C 5 Me 4 SiMe 2 OEt]ZrCl 2 (11) was considerably hampered by competitive Zr-Cl and Si-OEt bond splitting. When activated with MAO (methylalumoxane), 6-9 yield active ethylene polymerization systems.

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“…Direct introduction of reactive silyl end groups toward telechelic polyolefins was also effectively achieved through direct in situ end-functionalization via the use of silyl-functionalized chain-transfer agents (CTAs) . Lanthanides- , and early transition metals (Ti, Zr) − -catalyzed (co)polymerizations of α-olefins enabled to prepare various silyl-end-capped polyolefins along with the control of the molar mass values. For instance, primary alkylsilanes ( n -BuSiH 3 , PhCH 2 SiH 3 ) and arylsilanes (PhSiH 3 ) CTAs efficiently terminated growing polyethylene chains. , Selective organotitanium-mediated silanolytic (PhSiH 3 , PhMeSiH 2 , Me 2 SiH 2 , Et 2 SiH 2 ) chain transfer in the homogeneous polymerization and copolymerization of a variety of α-olefins (ethylene, propylene, 1-hexene, styrene) afforded silyl-capped and silyl-linked polyolefins. , Also, the possibility of forming silyl-terminated highly branched polyolefins by coupling an α-olefin with a CTA as one comonomer was first established with the polymerization of ethylene using Ti–alkyl precatalysts and a primary alkenylsilane (RSiH 3 ) comonomer/CTA. , …”

Section: Introductionmentioning

confidence: 99%

α-Trialkoxysilyl Functionalized Polycyclooctenes Synthesized by Chain-Transfer Ring-Opening Metathesis Polymerization

Diallo

Michel

Fouquay³

et al. 2015

Macromolecules

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International audienceRing-opening metathesis polymn./cross-metathesis (ROMP/CM) of cyclooctene (COE) or 3-alkyl-substituted COEs (3R-COEs, R = Et, n-hexyl) using several trialkoxysilyl monofunctionalized alkenes as chain-transfer agents (CTAs; vinyl trimethoxysilane (1), allyl trimethoxysilane (2), and 3-(trimethoxysilyl)propyl acrylate (3)) and various Ru-carbene-alkylidene catalysts afforded several trialkoxysilyl mono- and difunctionalized polyolefins. The formation of α-monofunctional (MF), α,ω-difunctional (DF), isomerized α-monofunctional (IMF), linear nonfunctional (LNF), isomerized linear nonfunctional (ILNF), and cyclic nonfunctional (CNF) PCOEs is rationalized by a two-stage mechanism. First, formation of monofunctionalized (MF) and nonfunctionalized (LNF, CNF) macromols. takes place through a ROMP/CM along with RCM (ring-closing metathesis) process. Subsequently, C=C isomerization (ISOM) combined with a second CM process give isomerized (ILNF, IMF) and difunctionalized (DF) macromols. The nonfunctionalized polymers (CNF, LNF, and ILNF) were formed in minor quantities compared to the trialkoxysilyl-functionalized polymers (MF, IMF, and DF), as evidenced by NMR and MALDI-ToF MS analyses and fractionation expts. The rate and selectivity of the reaction varied with the nature of the CTA, COE substituent, catalyst, and to a lesser extent of the solvent. The use of 1,4-benzoquinone (BZQ) as additive allowed inhibiting completely the ISOM process. Alternatively, steric hindrance in 3-RCOEs substituted monomers resulted in an ISOM-free process with selective formation of MF polymers. The reactive Grubbs' second-generation catalyst (G2) afforded the best compromise in terms of productivity, reactivity, and selectivity. Under optimized conditions favoring the formation of MF/DF, i.e., in CH2Cl2 at 40 °C for 24 h with [COE]0/[CTA 3]0/[G2]0/[BZQ]0 = 2000:20-200:1:100, the polymn. was rather well-controlled. While CTAs 1 and 3 selectively gave mixts. of MF and DF, allyl CTA 2 resulted in a mixt. of IMF, MF, and DF

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Silanolytic Chain Transfer in Olefin Polymerization with Supported Single-Site Ziegler−Natta Catalysts

Cited by 27 publications

References 9 publications

(ⁿBuCp)₂ZrCl₂‐catalyzed ethylene‐4M1P copolymerization: Copolymer backbone structure, melt behavior, and crystallization

(ⁿBuCp)₂ZrCl₂‐catalyzed ethylene‐4M1P copolymerization: Copolymer backbone structure, melt behavior, and crystallization

Silsesquioxane-bonded zirconocene complexes; soluble models for silica-tethered olefin polymerization catalysts

α-Trialkoxysilyl Functionalized Polycyclooctenes Synthesized by Chain-Transfer Ring-Opening Metathesis Polymerization

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Silanolytic Chain Transfer in Olefin Polymerization with Supported Single-Site Ziegler−Natta Catalysts

Cited by 27 publications

References 9 publications

(nBuCp)2ZrCl2‐catalyzed ethylene‐4M1P copolymerization: Copolymer backbone structure, melt behavior, and crystallization

(nBuCp)2ZrCl2‐catalyzed ethylene‐4M1P copolymerization: Copolymer backbone structure, melt behavior, and crystallization

Silsesquioxane-bonded zirconocene complexes; soluble models for silica-tethered olefin polymerization catalysts

α-Trialkoxysilyl Functionalized Polycyclooctenes Synthesized by Chain-Transfer Ring-Opening Metathesis Polymerization

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Product

Resources

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(ⁿBuCp)₂ZrCl₂‐catalyzed ethylene‐4M1P copolymerization: Copolymer backbone structure, melt behavior, and crystallization

(ⁿBuCp)₂ZrCl₂‐catalyzed ethylene‐4M1P copolymerization: Copolymer backbone structure, melt behavior, and crystallization