Spectroscopic and voltametric studies in titanium tris(pyrazolyl)borate catalysts

Autor:	Osvaldo L. Casagrande, J.H.Z. dos Santos, Zênis Novais da Rocha, Marcelo Priebe Gil, Lílian M.T. Simplício
Rok vydání:	2005
Předmět:	Olefin fiber Ethylene Process Chemistry and Technology Inorganic chemistry Solution polymerization Toluene Catalysis Hexane chemistry.chemical_compound chemistry Polymerization Physical and Theoretical Chemistry Solvent effects Nuclear chemistry
Zdroj:	Journal of Molecular Catalysis A: Chemical. 238:96-101
ISSN:	1381-1169
DOI:	10.1016/j.molcata.2005.04.043
Popis:	The ethylene polymerization using TpMs*TiCl3 (1) (TpMs* = HB(3-mesitylpyrazolyl)2(5-mesitylpyrazolyl)−) and TpMsTiCl3 (2) (TpMs = HB(3-mesityl-pyrazolyl)3−) was performed in toluene or hexane at 60 °C in the presence of MAO or TiBA/MAO (1:1) as cocatalysts. Higher activities were found for the polymerization reactions carried out in hexane, and using a combination of TiBA/MAO as cocatalysts. Absorciometric measurements in the UV–vis region and cyclic voltammetric have shown that such complexes when activated by MAO were not stable. Measurements carried out in the presence 1-hexene have demonstrated the necessity to add the cocatalyst in the presence of an olefin, i.e., ethylene or hexene-1 in order to stabilize the active species. Furthermore, these studies have revealed that after the activation process most of Ti remains as TiIV.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::0f19c71e54efc162dd05ef2104bbb37b https://doi.org/10.1016/j.molcata.2005.04.043 Zobrazit plný text záznamu Full Text from ScienceDirect