Über die Wirkungsweise löslicher Nickel-/Aluminium-Bimetallkatalysatoren auf der Basis von π-Cyclobutadien-Nickel-(II)-Verbindungen beider Niederdruck-Oligomerisation von Mono-Olefinen

Mixtures of π-cyclobutadiene-nickeldihalides and LEWIS acids such as Al(R)_nCl_3-n,, n = 1–2, represent very active homogeneous catalysts for dimerization of mono-olefins. As active cocatalyst may be used LEWIS bases, in particular compounds containing three-coordinated phosselectivity of the catalytic system has been investigated. The kinetics of the dimerization-reaction is outlined. The mechanisms of the olefin-dimerization is best characterized as a «double-cis-insertionreaction». The main catalytic activity is thought to be connected either to free positively charged nickel cations or to bimetallic nickel-aluminium-complexes, depending on theconditions of reaction, in particular the amount and chemical nature of the cocatalyst.     

Niederdruck-Oligomerisation von Mono-Olefinen mit löslichen Nickel/Aluminium-Bimetallkatalysatoren Teil III. Reaktionskinetische Untersuchungen über die Dimerisation und Trimerisation des Áthylens

The kinetics of the di- and trimerization of ethylen in organic solvents under the influence of a homogeneous catalyst containing π-tetramethylcyclobutadiene-nickeldichloride and a prereacted mixture of ethylaluminiumdichloride and tri-n-butylphosphine are reported. The primary reaction product is 1-butene, which is isomerized to 2-butene (cis/trans) during the reaction. The C₆-Olefins are formed by the reaction of ethylene with 1-butene and with the 2-butenes. The following primary reaction products are obtained: 3-hexene (cis/trans), 1-hexene, 2-ethyl-1-butene, 3-methyl-1-pentene and 3-methyl-2-pentene (cis/trans). The effect of other phosphines on the reaction was also studied. The relative composition of the reaction product is strongly dependent upon the amount and the LEWIS base strength of the phosphine present. The results are in accordance with a coordinative mechanism on nickel.     

Niederdruck-Oligomerisation von Mono-Olefinen mit löslichen Nickel/Aluminium-Bimetallkatalysatoren,Teil II Reaktionskinetische Untersuchungen über die Dimerisation von Propen

The kinetics of the dimerization of propene in organic solvents under the influence of a homogeneous catalyst containing π-tetramethylcyclobutadiene-nickel dichloride and a prereacted mixture of ethylaluminiumdichloride and tri-n-butylphosphin are reported. The primary reaction products are: 2-methyl-1-pentene, 4-methyl-2-pentene (cis/trans), 2,3-dimethyl-1-butene and 2-Hexene (cis/trans) The results are in accordance with a coordinative mechanism on nickel. New results on the reaction between ethylaluminiumdichloride and O, N and P containing electrondonors are also discussed.     

Niederdruck-Oligomerisation von Mono-Olefinen mit löslichen Nickel/Aluminium-Bimetallkatalysatoren,Teil I Entwicklung neuer Katalysatorsysteme auf der Basis von π-Cyclobutadien-Nickel(II)-Verbindungen

Mixtures of π-tetramethylcyclobutadiene-nickeldihalides and LEWIS acids such as alkylaluminiumhalides in organic solvents represent new highly active homogeneous catalysts for the dimerization of ethylen, propene and butene under mild conditions. As a cocatalyst LEWIS bases may be used, in particular those containing trivalent phosphorous.     

Niederdruck-Oligomerisation von Mono-Olefinen mit löslichen Nickel/Aluminium-Bimetallkatalysatoren,Teil IV. Reaktionskinetische Untesuchungen über die Codimerisation von Áthylen und Propen

The kinetics of the condimerization of ethylene and propene in organic solvents under the influence of a homogeneous catalyst containing π-tetramethylcyclobutadiene-nickeldichloride and a prereacted mixture of ethylaluminiumdichloride and tri-n-butylphosphine are reported. The primary reaction products are: 1-pentene, 2-pentene (cis/trans), 2-methyl-1-butene and 3-methyl-1-butene. The effect of other phosphines was also studied. The activity as well as the selectivity of the catalyst are strongly dependent upon the amount and the LEWIS base strength of the phosphine present. The results are in accordance with a coordinative mechanism on nickel.