View in EDS HTML Full Text PDF Full Text

α-Olefin Oligomerization Mediated by Group 4 Metallocene Catalysts: An Extreme Manifestation of the Multisite Nature of Methylaluminoxane.

Saved in:
Bibliographic Details
Title: α-Olefin Oligomerization Mediated by Group 4 Metallocene Catalysts: An Extreme Manifestation of the Multisite Nature of Methylaluminoxane.
Authors: Zaccaria, Francesco1 (AUTHOR) francesco.zaccaria@unina.it, Vittoria, Antonio1 (AUTHOR), Antinucci, Giuseppe1 (AUTHOR) giuseppe.antinucci@unina.it, Cipullo, Roberta1 (AUTHOR) giuseppe.antinucci@unina.it, Busico, Vincenzo1 (AUTHOR)
Source: Polymers (20734360). Jan2025, Vol. 17 Issue 1, p46. 11p.
Subjects: High performance liquid chromatography, Metallocene catalysts, Lewis acidity, Molecular weights, Metallocenes
Abstract: Group 4 metallocenes are competent catalysts for the oligomerization of higher α-olefins. Among the many chemical and physical variables of importance in the process, one is the choice of cocatalyst (activator). The impact of various activators on the performance of a representative catalyst, (nBuCp)2ZrCl2, in the oligomerization of 1-octene was thoroughly investigated; in particular, the molecular weight distribution (MWD) of the oligomers was determined by means of high-resolution high performance liquid chromatography (HR-HPLC). Unexpectedly, a bimodal MWD was highlighted when the precatalyst was activated with methylaluminoxane (MAO), whereas a single Schulz–Flory (SF) MWD was observed with borate salts. The presence of Al centers with different Lewis acidity in the complex and ill-defined structure of MAO is well known, and the broadening effects on the MWD of olefin polymerization products made with metallocene/MAO catalyst systems have been reported before. However, to the best of our knowledge, clear HR-HPLC evidence of two active species resulting from activation with MAO of one single zirconocene precursor, yielding two discrete SF product distributions, is unprecedented. By varying the polarity of the reaction medium, we managed to modulate the MWD of the oligomers from bimodal to monomodal, even with MAO, thus demonstrating that ion pairing effects are behind these unusual findings. [ABSTRACT FROM AUTHOR]
Copyright of Polymers (20734360) is the property of MDPI and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
Full text is not displayed to guests.
FullText Links:
  – Type: pdflink
Text:
  Availability: 1
Header DbId: egs
DbLabel: Engineering Source
An: 182433090
AccessLevel: 6
PubType: Academic Journal
PubTypeId: academicJournal
PreciseRelevancyScore: 0
IllustrationInfo
Items – Name: Title
  Label: Title
  Group: Ti
  Data: α-Olefin Oligomerization Mediated by Group 4 Metallocene Catalysts: An Extreme Manifestation of the Multisite Nature of Methylaluminoxane.
– Name: Author
  Label: Authors
  Group: Au
  Data: <searchLink fieldCode="AR" term="%22Zaccaria%2C+Francesco%22">Zaccaria, Francesco</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> francesco.zaccaria@unina.it</i><br /><searchLink fieldCode="AR" term="%22Vittoria%2C+Antonio%22">Vittoria, Antonio</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Antinucci%2C+Giuseppe%22">Antinucci, Giuseppe</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> giuseppe.antinucci@unina.it</i><br /><searchLink fieldCode="AR" term="%22Cipullo%2C+Roberta%22">Cipullo, Roberta</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> giuseppe.antinucci@unina.it</i><br /><searchLink fieldCode="AR" term="%22Busico%2C+Vincenzo%22">Busico, Vincenzo</searchLink><relatesTo>1</relatesTo> (AUTHOR)
– Name: TitleSource
  Label: Source
  Group: Src
  Data: <searchLink fieldCode="JN" term="%22Polymers+%2820734360%29%22">Polymers (20734360)</searchLink>. Jan2025, Vol. 17 Issue 1, p46. 11p.
– Name: Subject
  Label: Subjects
  Group: Su
  Data: <searchLink fieldCode="DE" term="%22High+performance+liquid+chromatography%22">High performance liquid chromatography</searchLink><br /><searchLink fieldCode="DE" term="%22Metallocene+catalysts%22">Metallocene catalysts</searchLink><br /><searchLink fieldCode="DE" term="%22Lewis+acidity%22">Lewis acidity</searchLink><br /><searchLink fieldCode="DE" term="%22Molecular+weights%22">Molecular weights</searchLink><br /><searchLink fieldCode="DE" term="%22Metallocenes%22">Metallocenes</searchLink>
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: Group 4 metallocenes are competent catalysts for the oligomerization of higher α-olefins. Among the many chemical and physical variables of importance in the process, one is the choice of cocatalyst (activator). The impact of various activators on the performance of a representative catalyst, (nBuCp)2ZrCl2, in the oligomerization of 1-octene was thoroughly investigated; in particular, the molecular weight distribution (MWD) of the oligomers was determined by means of high-resolution high performance liquid chromatography (HR-HPLC). Unexpectedly, a bimodal MWD was highlighted when the precatalyst was activated with methylaluminoxane (MAO), whereas a single Schulz–Flory (SF) MWD was observed with borate salts. The presence of Al centers with different Lewis acidity in the complex and ill-defined structure of MAO is well known, and the broadening effects on the MWD of olefin polymerization products made with metallocene/MAO catalyst systems have been reported before. However, to the best of our knowledge, clear HR-HPLC evidence of two active species resulting from activation with MAO of one single zirconocene precursor, yielding two discrete SF product distributions, is unprecedented. By varying the polarity of the reaction medium, we managed to modulate the MWD of the oligomers from bimodal to monomodal, even with MAO, thus demonstrating that ion pairing effects are behind these unusual findings. [ABSTRACT FROM AUTHOR]
– Name: AbstractSuppliedCopyright
  Label:
  Group: Ab
  Data: <i>Copyright of Polymers (20734360) is the property of MDPI and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.)
PLink https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=182433090
RecordInfo BibRecord:
  BibEntity:
    Identifiers:
      – Type: doi
        Value: 10.3390/polym17010046
    Languages:
      – Code: eng
        Text: English
    PhysicalDescription:
      Pagination:
        PageCount: 11
        StartPage: 46
    Subjects:
      – SubjectFull: High performance liquid chromatography
        Type: general
      – SubjectFull: Metallocene catalysts
        Type: general
      – SubjectFull: Lewis acidity
        Type: general
      – SubjectFull: Molecular weights
        Type: general
      – SubjectFull: Metallocenes
        Type: general
    Titles:
      – TitleFull: α-Olefin Oligomerization Mediated by Group 4 Metallocene Catalysts: An Extreme Manifestation of the Multisite Nature of Methylaluminoxane.
        Type: main
  BibRelationships:
    HasContributorRelationships:
      – PersonEntity:
          Name:
            NameFull: Zaccaria, Francesco
      – PersonEntity:
          Name:
            NameFull: Vittoria, Antonio
      – PersonEntity:
          Name:
            NameFull: Antinucci, Giuseppe
      – PersonEntity:
          Name:
            NameFull: Cipullo, Roberta
      – PersonEntity:
          Name:
            NameFull: Busico, Vincenzo
    IsPartOfRelationships:
      – BibEntity:
          Dates:
            – D: 01
              M: 01
              Text: Jan2025
              Type: published
              Y: 2025
          Identifiers:
            – Type: issn-print
              Value: 20734360
          Numbering:
            – Type: volume
              Value: 17
            – Type: issue
              Value: 1
          Titles:
            – TitleFull: Polymers (20734360)
              Type: main
ResultId 1