Olefin oligomerization by novel catalysts prepared by oxidative addition of carboxylic acids to nickel(0) precursors and modified by phosphine ancillary ligands and organoaluminum compounds
C. Carlini et al., Olefin oligomerization by novel catalysts prepared by oxidative addition of carboxylic acids to nickel(0) precursors and modified by phosphine ancillary ligands and organoaluminum compounds, J MOL CAT A, 169(1-2), 2001, pp. 79-88
Novel Ziegler-Natta-type catalysts, prepared in situ by oxidative addition
of carboxylic acids to bis(cyclooctadiene)nickel(0) [Ni(cod)(2)]/phosphine
adducts and activated by different organoaluminum compounds, are described.
These catalysts resulted very active in olefin oligomerization. When 2-nit
robenzoic acid (NBA), tricyclohexylphosphine (PCy3) and MAO were employed i
n combination with Ni(cod)(2) for propylene oligomerization. a regioselecti
vity to 2,3-dimethylbutenes (DMB) within the C-6 cut very close to 90% was
achieved with a high productivity (turnover frequency (TOF) values up to 16
,400 h(-1)). Similar results in terms of regioselectivity to DMB were obtai
ned when trifluoroacetic acid (TFA) was adopted. However, although with a l
ower productivity, a higher value of overall yield to DMB (62.7%) was achie
ved. When these catalysts were used for ethylene oligomerization they resul
ted very active (TOF values up to 65,000 h(-1)). the nature of the phosphin
e ligand allowing to strongly affect the chemoselectivity of the process, s
hifting the oligomeric composition towards specific fractions. (C) 2001 Els
evier Science B.V. All rights reserved.