Improved heterogenized catalysts for selective propylene oligomerization to 2,3-dimethylbutenes prepared by oxidative addition of polymer-anchored beta-dithioacetylacetonate ligands to nickel(0) complexes
C. Carlini et al., Improved heterogenized catalysts for selective propylene oligomerization to 2,3-dimethylbutenes prepared by oxidative addition of polymer-anchored beta-dithioacetylacetonate ligands to nickel(0) complexes, APP CATAL A, 207(1-2), 2001, pp. 387-395
A novel approach for obtaining heterogenized catalysts, via oxidative addit
ion of polymer-bound beta -dithioacetylacetonate (sacsac) ligands to nickel
(0) complexes was reported and their performances were investigated in the
propylene oligomerization, in terms of activity and selectivity to 2,3-dime
thylbutenes (DMB). In particular, the effect of the nature of the ancillary
phosphine ligand as well as of the organoaluminium co-catalyst was studied
. The influence of the addition to the reaction medium of chlorinated promo
ters was also checked. The results indicated that the catalysts prepared by
this route were more active and selective towards DMB as compared with tho
se previously prepared by an exchange reaction method. When basic alkyl pho
sphines, such as tricyclohexylphosphine (PCy3) and triisopropylphosphine ((
PPr3)-Pr-i), and organoaluminium co-catalysts with suitable Lewis acidity,
such as Et2AlCl, were used, the resulting catalysts displayed a very high s
electivity to DMB (similar to 80%) and an extremely high productivity (turn
over frequency equal to 74,000 h(-1)), the latter being much higher as comp
ared with that previously obtained with the homogeneous counterparts. (C) 2
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