Ethylene oligomerization using nickel-β-diimine hybrid xerogels produced by the sol–gel process

Authors: Enéderson Rossetto, Marcela Caovilla, Daniel Thiele, Roberto F. de Souza, Katia Bernardo-Gusmão

Abstract:
Nickel--diimine complexes have been used as homogeneous- and heterogeneous-phase oligomerization catalysts. The following complexes have also been heterogenized on silica using the sol–gel method: 1,5-bis(phenyl)-pentanediimine-dibromonickel(II) (A), 1,5-bis(2,6- dimethylphenyl)-2,4-pentanediimine-dibromonickel(II) (B) and 1,5-bis(2,4,6-trimethylphenyl)-2, 4-pentanediimine-dibromonickel(II) (C). The synthesis of the xerogels was performed employing 3-chloropropyltrimethoxysilane (CPTMS), tetraethylorthosilicate (TEOS) and HF. The hybrid - diimine/silica materials are used in combination with ethylaluminum sesquichloride (EASC) and have been shown to be outstanding ethylene oligomerization catalyst systems. Under mild reactions conditions, the homogeneous and heterogenized catalysts had high turnover frequencies (between 1800 and 210,000 h−1). The best selectivities were obtained with the heterogenized catalysts, which give 100% of C4 fraction with 1-butene selectivities of up to 91%.

Keywords:
Oligomerization
Ethylene
β-Diimine
Xerogel
Sol–gel process
Organic–inorganic hybrid materials

Published in: Applied catalysis A: General  (Volume 454, Pages 1-172, 15 March 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

Ethylene oligomerization using nickel-β-diimine hybrid xerogels produced by the sol–gel process

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