Catalytic performances of homogeneous systems based on alpha-nitroacetophenonate-nickel(II) complexes and organoaluminium compounds in ethylene oligomerisation
C. Carlini et al., Catalytic performances of homogeneous systems based on alpha-nitroacetophenonate-nickel(II) complexes and organoaluminium compounds in ethylene oligomerisation, APP CATAL A, 216(1-2), 2001, pp. 1-8
The catalytic behaviour of novel alpha -nitroacetophenonate-nickel(II) comp
lexes has been investigated as a function of reaction conditions, type and
relative amount of the organoaluminium co-catalyst, as well as nature of th
e ancillary phosphine ligand, in order to orientate ethylene oligomerisatio
n process towards specific target products. The reported data allowed to in
dicate that it is possible to shift the products distribution towards highe
r oligomers by increasing the Lewis acidity of the organoaluminium co-catal
yst and by using a basic and bulky ancillary ligand such as tricyclohexylph
osphine (PCy3). The catalyst productivity may be also readily modulated by
choosing the proper organoaluminium co-catalyst and the suitable phosphine
ancillary ligand. Under proper reaction conditions, a very high linearity (
more than 80% of n-hexenes) of the C-6 cut was obtained. On the other side,
the mixture of the higher oligomeric components was found to have a relati
vely high degree of branching. This is likely due to the ability of the cat
alytic system to co-oligomerise ethylene with the produced dimeric and trim
eric alpha -olefins, thus, affording more branched higher oligomers. (C) 20
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