To produce the subject straight-chain low polymer with an excellent catalyst efficiency in high yield and high selectivity without requiring strict operation control by using a nickel compound and an organoaluminum compound subjected to a specific pretreatment in combination and thereby using an oligomerization reactional catalyst system excellent in operating efficiency.
When a raw olefin (preferably butenes) is subjected to an oligomerizing reaction, (A) a nickel compound and (B) an organoaluminum compound subjected to a mixing pretreatment with a chelate compound are used as a catalyst. Bis(1,1,1,5,5,5-hexafluoro-2, 4-pentanedionato)nickel is preferably used as the component A and a trialkylaluminum subjected to the mixing pretreatment with 1,1,1,5,5,5-hexafluoro-2,4-pentanedione is preferably used as the component B. At the time of the oligomerizing reaction, the components A and B are preferably brought into contact each other in the presence of an olefin as a stabilizer.
AOSHIMA NORIYUKI
TANAKA YOSHIYUKI
URATA HISAO
