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

Abstract

Summary. The kinetics of the di-and trimerization of etliylen in organic solvents under the influence of a homogeneous catalyst containing n-tetramethylcyclobutadiene-nickeldichloride and a prereacted mixture of cthylaluminiumdichloride and tri-n-butylphosphine are reported. The primary reaction product is 1-butene, which is isomerized to 2-butcne (cis/tvuns) during the reaction. The C,-Olefins are formed by the reaction of ethylene with 1-butene and with the 2-butenes. The following primary reaction products are obtained : 3-hcxenc (cis/trans), 1-hexene, 2-ethyl-1-butene, 3-methyl-1-pentene and 3-methyl-2-pentene (cisltrans) .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. 1.Einleitung. -Aus der relativen Bereitwilligkeit der Olefine Athylen, Propen und Buten zur Dimerisation und der Struktur der dabei gebildeten Primarprodukte lassen sich wertvolle Erkenntnisse iiber die Wirkungsweise der verwendeten Katalysatorsysteme gewinnen. Im Anschluss an unsere Arbeit uber die Dimerisation des Propens [l] wird hier iiber die Reaktionskinetik der Di-und Trimerisation des AtIlylens unter dern katalytischen Einfluss einer Mischung von Tetramethylcyclobutadiennickeldichlorid, [TMCBINiCl,, und einem vorreagierten Geniisch von Monoathylaluminiumdichlorid und Tri-%-Butylphosphin berichtet. Versuche mit anderen Phosphinen sollen zu vertieftem Verstandnis der aktivierenden und insbesondere der stereoregulierenden Wirkung der Phosphine im Katalysatorsystem beitragen.

Dimerization of Linear Butenes on Zeolite-Supported Ni2+

“…The reaction orders obtained for the formation of octene and methylheptene (Figure ), with respect to 1-butene, were approximately 2 (Figure S7C,D). This points to the C–C coupling of the two weakly adsorbed butenes as the rate-determining step (rds), in agreement with studies on ethene dimerization. ,− The measured activation energies for the formation of the specific dimers, as well as for the different oligomers, are shown in Table (Arrhenius plots are shown in Figure S7A,B in the Supporting Information). The reaction order and activation energy were not measured for dimethylhexene, since it is a secondary product.…”