Ethylene linear 1-alkene production

Either triphenylarsonium benzoylylide or dibenzoylylide form complexes with bis(l,5-cyclo-octadiene)nickel these oligomerise ethylene under mild conditions . The dibenzoyl derivative is the more effective catalyst of the two, this being ascribed to the greater stabilization provided by the second benzoyl group the monobenzoyl derivative provides largely linear alkenes, but the dibenzoyl derivative leads to decreased linearity in the products. 

Ethylene Oligomerization Processes for Linear l-Alkene Production 749... 

Scheme 6.16.1 Ethylene oligomerization is the method of choice to produce 1-alkenes (= linear ct-olefins). The worldwide capacity for 1-alkene production was above 3 Mio tons in 2010.

The major product of ethylene oligomerization in the presence of Ni-ylide-aluminum alcoxides are linear 1-alkenes with even carbon atom numbers, from C4 to 40- In addition to 1-alkenes, linear alkenes with internal double bonds (trans and cis) are always present in the reaction product. 

Linear Alkenes.—Addition of Nucleophiles. Nucleophilic attack on co-ordinated olefins generally occurs only with strong nucleophiles or if the complex is activated, e.g. if it is positively charged. However, malonate ester anions readily add to an olefinic carbon atom of [Fe(CO)4olefin] (olefin=ethylene or methylacrylate). Acidic work-up affords alkene addition products in good yield, equation (4), and a... 

The treatment of equivalent amounts of two different alkenes with a metathesis catalyst generally leads to the formation of complex product mixtures [925,926]. There are, however, several ways in which cross metathesis can be rendered synthetically useful. One example of an industrial application of cross metathesis is the ethenolysis of internal alkenes. In this process cyclic or linear olefins are treated with ethylene at 50 bar/20 80 °C in the presence of a heterogeneous metathesis catalyst. The reverse reaction of ADMET/RCM occurs, and terminal alkenes are obtained. 

Due to the regular branched structure of this isomer, linear 1-alkenes heavier than 1-heptene are not present and the relative amount of propyl and butyl radicals is significantly different too. In other words, the lumped H-abstraction reaction of a single model component loses the variety of primary products obtained from the previous lumped A0C15. It seems relevant to observe that to improve ethylene selectivity prediction, alkene components heavier than hexenes can be conveniently described with two different species, respectively corresponding to the true component 1-C H2 and to a lumped mixture of the remaining normal and branched isomers. 

The nickel concentration in the catalyst system is in the range 0.001-0.005 mol% (approx. 10-50 ppm). The oligomerization is carried out in a series of reactors at temperatures of 80-140°C and pressures of 7-14 MPa. The rate of the reaction is controlled by the rate of catalyst addition [19]. A high partial pressure of ethylene is required to obtain good reaction rates and high product linearity [11]. The linear a-alkenes produced are obtained in a Schulz-Flory-type distribution with up to 99% linearity and 96-98% terminal alkenes over the whole range from C4 to C+ (cf. Table 2) [23]. 

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