Organo-fn,d0-mediated synthesis of amine-capped polyethylenes. Scope and mechanism

Smruti B. Amin, SungYong Seo, Tobin J Marks

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Amines of varying Brønsted acidity and steric encumberance are investigated as chain-transfer agents to functionalize polyolefins via organolanthanide-mediated olefin polymerization processes. Ethylene homopolymerizations are carried out with activated Cp′ 2LnCH(Si(CH3)3)2 (Cp′ = η5-Me5C5; Ln = La, Sm, Y, Lu) precatalysts in the presence of aniline, n-propylamine, N,N-bis(trimethylsilyl)amine, di-sec-butylamine, N-tert-butyl(trimethylsilyl)amine, di-isopropylamine, and dicyclohexylamine. In the presence of these amines, polymerization activities up to 104 g polymer/(mol of Ln · atm ethylene · h) and narrow product polymer polydispersities are observed, consistent with single-site polymerization processes. Amine chain-transfer efficiency follows the trend C6H5NH2nC 3H7NH2 3) 3]2NH ≈ secBu2NH <N- tBu[Si(CH3)3]NH ≈ iPr 2NH <Cy2NH to yield polyethylenes of the structure H(CH2CH2)nNRR′, where an efficient chain-transfer agent is defined as a reagent that both terminates polymer chain growth and facilitates reinitiation of polymer chain growth. Under the conditions investigated, primary amines are found to be the most inert toward Cp′2La-mediated polymerizations, affording no detectable insertion products, while di-sec-butylamine and N,N-bis(trimethylsilyl)amine are marginally efficient and produce monoethylene insertion products. In contrast, N-tert-butyl(trimethylsilyl)amine and di-isopropylamine afford amine-capped oligoethylenes, while dicyclohexylamine is the most efficient chain-transfer agent investigated, producing high molecular weight amine-terminated polyethylenes. For these Ln catalysts, dicyclohexylamine chain transfer exhibits a linear relationship between product Mn and [dicyclohexyl-amine] -1, consistent with a well-behaved aminolysis chain termination pathway. In all of the above systems, protonolysis appears to be the dominant chain-transfer pathway. Organotitanium-mediated ethylene and propylene polymerizations in the presence of secondary amines result in modest polymerization rates with activities of 104 g polymer/(mol of Ti · atm ethylene · h).

Original languageEnglish
Pages (from-to)2411-2420
Number of pages10
JournalOrganometallics
Volume27
Issue number11
DOIs
Publication statusPublished - Jun 9 2008

Fingerprint

Polyethylenes
Amines
polyethylenes
amines
synthesis
polymerization
Polymerization
Polymers
ethylene
Butylamines
polymers
products
insertion
Propylamines
Polydispersity
Alkenes
aniline
Homopolymerization
propylene

ASJC Scopus subject areas

  • Inorganic Chemistry
  • Organic Chemistry

Cite this

Organo-fn,d0-mediated synthesis of amine-capped polyethylenes. Scope and mechanism. / Amin, Smruti B.; Seo, SungYong; Marks, Tobin J.

In: Organometallics, Vol. 27, No. 11, 09.06.2008, p. 2411-2420.

Research output: Contribution to journalArticle

Amin, Smruti B. ; Seo, SungYong ; Marks, Tobin J. / Organo-fn,d0-mediated synthesis of amine-capped polyethylenes. Scope and mechanism. In: Organometallics. 2008 ; Vol. 27, No. 11. pp. 2411-2420.
@article{a753c781d1ee42448d0f7ba9171a3938,
title = "Organo-fn,d0-mediated synthesis of amine-capped polyethylenes. Scope and mechanism",
abstract = "Amines of varying Br{\o}nsted acidity and steric encumberance are investigated as chain-transfer agents to functionalize polyolefins via organolanthanide-mediated olefin polymerization processes. Ethylene homopolymerizations are carried out with activated Cp′ 2LnCH(Si(CH3)3)2 (Cp′ = η5-Me5C5; Ln = La, Sm, Y, Lu) precatalysts in the presence of aniline, n-propylamine, N,N-bis(trimethylsilyl)amine, di-sec-butylamine, N-tert-butyl(trimethylsilyl)amine, di-isopropylamine, and dicyclohexylamine. In the presence of these amines, polymerization activities up to 104 g polymer/(mol of Ln · atm ethylene · h) and narrow product polymer polydispersities are observed, consistent with single-site polymerization processes. Amine chain-transfer efficiency follows the trend C6H5NH2 ≈ nC 3H7NH2 3) 3]2NH ≈ secBu2NH <N- tBu[Si(CH3)3]NH ≈ iPr 2NH <Cy2NH to yield polyethylenes of the structure H(CH2CH2)nNRR′, where an efficient chain-transfer agent is defined as a reagent that both terminates polymer chain growth and facilitates reinitiation of polymer chain growth. Under the conditions investigated, primary amines are found to be the most inert toward Cp′2La-mediated polymerizations, affording no detectable insertion products, while di-sec-butylamine and N,N-bis(trimethylsilyl)amine are marginally efficient and produce monoethylene insertion products. In contrast, N-tert-butyl(trimethylsilyl)amine and di-isopropylamine afford amine-capped oligoethylenes, while dicyclohexylamine is the most efficient chain-transfer agent investigated, producing high molecular weight amine-terminated polyethylenes. For these Ln catalysts, dicyclohexylamine chain transfer exhibits a linear relationship between product Mn and [dicyclohexyl-amine] -1, consistent with a well-behaved aminolysis chain termination pathway. In all of the above systems, protonolysis appears to be the dominant chain-transfer pathway. Organotitanium-mediated ethylene and propylene polymerizations in the presence of secondary amines result in modest polymerization rates with activities of 104 g polymer/(mol of Ti · atm ethylene · h).",
author = "Amin, {Smruti B.} and SungYong Seo and Marks, {Tobin J}",
year = "2008",
month = "6",
day = "9",
doi = "10.1021/om700831t",
language = "English",
volume = "27",
pages = "2411--2420",
journal = "Organometallics",
issn = "0276-7333",
publisher = "American Chemical Society",
number = "11",

}

TY - JOUR

T1 - Organo-fn,d0-mediated synthesis of amine-capped polyethylenes. Scope and mechanism

AU - Amin, Smruti B.

AU - Seo, SungYong

AU - Marks, Tobin J

PY - 2008/6/9

Y1 - 2008/6/9

N2 - Amines of varying Brønsted acidity and steric encumberance are investigated as chain-transfer agents to functionalize polyolefins via organolanthanide-mediated olefin polymerization processes. Ethylene homopolymerizations are carried out with activated Cp′ 2LnCH(Si(CH3)3)2 (Cp′ = η5-Me5C5; Ln = La, Sm, Y, Lu) precatalysts in the presence of aniline, n-propylamine, N,N-bis(trimethylsilyl)amine, di-sec-butylamine, N-tert-butyl(trimethylsilyl)amine, di-isopropylamine, and dicyclohexylamine. In the presence of these amines, polymerization activities up to 104 g polymer/(mol of Ln · atm ethylene · h) and narrow product polymer polydispersities are observed, consistent with single-site polymerization processes. Amine chain-transfer efficiency follows the trend C6H5NH2 ≈ nC 3H7NH2 3) 3]2NH ≈ secBu2NH <N- tBu[Si(CH3)3]NH ≈ iPr 2NH <Cy2NH to yield polyethylenes of the structure H(CH2CH2)nNRR′, where an efficient chain-transfer agent is defined as a reagent that both terminates polymer chain growth and facilitates reinitiation of polymer chain growth. Under the conditions investigated, primary amines are found to be the most inert toward Cp′2La-mediated polymerizations, affording no detectable insertion products, while di-sec-butylamine and N,N-bis(trimethylsilyl)amine are marginally efficient and produce monoethylene insertion products. In contrast, N-tert-butyl(trimethylsilyl)amine and di-isopropylamine afford amine-capped oligoethylenes, while dicyclohexylamine is the most efficient chain-transfer agent investigated, producing high molecular weight amine-terminated polyethylenes. For these Ln catalysts, dicyclohexylamine chain transfer exhibits a linear relationship between product Mn and [dicyclohexyl-amine] -1, consistent with a well-behaved aminolysis chain termination pathway. In all of the above systems, protonolysis appears to be the dominant chain-transfer pathway. Organotitanium-mediated ethylene and propylene polymerizations in the presence of secondary amines result in modest polymerization rates with activities of 104 g polymer/(mol of Ti · atm ethylene · h).

AB - Amines of varying Brønsted acidity and steric encumberance are investigated as chain-transfer agents to functionalize polyolefins via organolanthanide-mediated olefin polymerization processes. Ethylene homopolymerizations are carried out with activated Cp′ 2LnCH(Si(CH3)3)2 (Cp′ = η5-Me5C5; Ln = La, Sm, Y, Lu) precatalysts in the presence of aniline, n-propylamine, N,N-bis(trimethylsilyl)amine, di-sec-butylamine, N-tert-butyl(trimethylsilyl)amine, di-isopropylamine, and dicyclohexylamine. In the presence of these amines, polymerization activities up to 104 g polymer/(mol of Ln · atm ethylene · h) and narrow product polymer polydispersities are observed, consistent with single-site polymerization processes. Amine chain-transfer efficiency follows the trend C6H5NH2 ≈ nC 3H7NH2 3) 3]2NH ≈ secBu2NH <N- tBu[Si(CH3)3]NH ≈ iPr 2NH <Cy2NH to yield polyethylenes of the structure H(CH2CH2)nNRR′, where an efficient chain-transfer agent is defined as a reagent that both terminates polymer chain growth and facilitates reinitiation of polymer chain growth. Under the conditions investigated, primary amines are found to be the most inert toward Cp′2La-mediated polymerizations, affording no detectable insertion products, while di-sec-butylamine and N,N-bis(trimethylsilyl)amine are marginally efficient and produce monoethylene insertion products. In contrast, N-tert-butyl(trimethylsilyl)amine and di-isopropylamine afford amine-capped oligoethylenes, while dicyclohexylamine is the most efficient chain-transfer agent investigated, producing high molecular weight amine-terminated polyethylenes. For these Ln catalysts, dicyclohexylamine chain transfer exhibits a linear relationship between product Mn and [dicyclohexyl-amine] -1, consistent with a well-behaved aminolysis chain termination pathway. In all of the above systems, protonolysis appears to be the dominant chain-transfer pathway. Organotitanium-mediated ethylene and propylene polymerizations in the presence of secondary amines result in modest polymerization rates with activities of 104 g polymer/(mol of Ti · atm ethylene · h).

UR - http://www.scopus.com/inward/record.url?scp=45449092169&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=45449092169&partnerID=8YFLogxK

U2 - 10.1021/om700831t

DO - 10.1021/om700831t

M3 - Article

VL - 27

SP - 2411

EP - 2420

JO - Organometallics

JF - Organometallics

SN - 0276-7333

IS - 11

ER -