The present invention provides a catalyst
system for
ethylene oligomerization, its preparation method and application. The catalyst
system includes: a chloro-2-C1-C6 acyl-1,10-
phenanthroline-condensed-2,6-
dimethylaniline iron(II) complex shown in formula (1), an aluminum-containing cocatalyst, water and
cyclohexane; in formula (1), R is selected from C1-C6
alkyl groups; R1-R6 are the same or different and are each independently selected from
hydrogen, C1-C6
alkyl groups, halogens, C1-C6 alkoxy groups and nitro groups. Under the action of this catalyst
system for
ethylene oligomerization, due to the action of the
promoter water, the oligomerization reaction is initiated rapidly, operates stably, has good
repeatability, and the
reaction temperature can be 60-80 °C. The heat removal medium for the reaction can use
condensed water, which reduces
energy consumption compared with
chilled water. Thus, it overcomes the technical prejudice of those skilled in the art and achieves unexpected technical effects.