Synthesis, Characterization and Ethylene Oligomerization Studies of Chromium Complexes Bearing Imino-Furfural Ligands

• Autor(a) principal: Ulbrich,Ana H. D. P. S.
• Data de Publicação: 2014
• Outros Autores: Milani,Jorge L. S., Livotto,Paolo R., Carpentier,Jean-François, Casagrande Jr.,Osvaldo L.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532014001202466
• topic: imino-fufural ligands; chromium complexes; ethylene oligomerization

A series of chromium(III) complexes bearing imino-furfural ligands (Cr1-Cr4) were synthesized and characterized by high-resolution mass spectrometry (HRMS). All chromium precatalysts, activated with methylaluminoxane (MAO), exhibited moderate to high activities for ethylene oligomerization [turnover frequency (TOF) = 11,008-23,200 mol(ethylene) mol(Cr)-1 h-1)] producing oligomers in the range C4-C12+ with good selectivity for α-olefins. The in situ chromium precatalysts formed by mixing imino-furfural ligand L1 with [CrCl3(THF)3] or [Cr(acac)3] showed low activities, producing oligomers together with varying amounts of polyethylene. The use of different chromium sources and cocatalysts influences the activity as well as the selectivities toward α-olefin production, which suggests that different active species are formed.