Você está no menu de acessibilidade

Utilize este identificador para citar ou criar um link para este item: http://acervodigital.unesp.br/handle/11449/36019
Título: 
Titanium and zirconium complexes containing sterically hindered hydrotris(pyrazolyl)borate ligands: synthesis, structural characterization, and ethylene polymerization studies
Autor(es): 
Instituição: 
  • Universidade Federal do Rio Grande do Sul (UFRGS)
  • Universidade Estadual Paulista (UNESP)
ISSN: 
0022-328X
Resumo: 
The synthesis, characterization and ethylene polymerization behavior of a set of Tp'MCl3 complexes (4, M = Ti, Tp' HB(3-neopentyl-pyrazolyl)(3)(-) (Tp(NP)); 5, M = Ti, Tp'= HB(3-tert-butyl-pyrazolyl)(3)(-) (Tp(tBu)); 6, M = Ti, Tp' = HB(3-phenyl-pyrazolyl)(3)(-) (Tp(Ph)); 7, M = Zr, Tp' = HB(3-phenyl-pyrazolyl)(3)(-) (Tp(ph)); 8, M = Zr, Tp' = HB(3-tert-butyl-pyrazolyl)(3)(-) (Tp(tBu))) is described. Treatment of these tris(pyrazolyl)borate Group IV compounds with methylalumoxane (MAO) generates active catalysts for ethylene polymerization. For the polymerization reactions performed in toluene at 60 degreesC and 3 atm of ethylene pressure, the activities varied between 1.3 and 5.1 X 10(3) g of PE/mol[M](.)h. The highest activity is reached using more sterically open catalyst precursor 4. The viscosity-average molecular weights ((M-v) over bar) of the PE's produced with these catalyst precursors varying from 3.57 to 20.23 x 10(5) gmol(-1) with melting temperatures in the range of 127-134 degreesC. Further polymerization studies employing 7 varying Al/Zr molar ratio and temperature of polymerization showed that the activity as well as the polymer properties are dependent on these parameters. In that case, higher activity was attained at 60 degreesC. The viscosity-average molecular weights of the polyethylene's decreases with increasing AI/Zr molar ratio. (C) 2003 Elsevier B.V. All rights reserved.
Data de publicação: 
15-Jan-2004
Citação: 
Journal of Organometallic Chemistry. Lausanne: Elsevier B.V. Sa, v. 689, n. 2, p. 286-292, 2004.
Duração: 
286-292
Publicador: 
Elsevier B.V.
Palavras-chaves: 
  • tris(pyrazolyl)borate ligands
  • titanium and zirconium
  • ethylene
  • polymerization
Fonte: 
http://dx.doi.org/10.1016/j.jorganchem.2003.10.013
Endereço permanente: 
Direitos de acesso: 
Acesso restrito
Tipo: 
outro
Fonte completa:
http://repositorio.unesp.br/handle/11449/36019
Aparece nas coleções:Artigos, TCCs, Teses e Dissertações da Unesp

Não há nenhum arquivo associado com este item.
 

Itens do Acervo digital da UNESP são protegidos por direitos autorais reservados a menos que seja expresso o contrário.