Ethylene oligomerization method, and ethylene oligomer thereof

A method for oligomerization of ethylene, comprising a step of producing an ethylene oligomer by reacting ethylene with a catalyst, a cocatalyst, and a chain transfer agent in the presence of an organic compound,

• wherein the ethylene oligomer contains an amount of polyethylene that is 0.1 wt % or less;
• and
• wherein the catalyst is a chromium complex represented by Formula 1 below, the cocatalyst is an organoaluminum compound represented by Formula 2 below, and the chain transfer agent is a compound represented by Formula 3 below:
• Al(R11)3 [Formula 2]
• Zn(R22)2 [Formula 3]
• wherein
• R is a C1-C60 alkyl, a C6-C60 aryl, or a C2-C60 heteroaryl containing at least one heteroatom selected from the group consisting of O, N, S, Si and P;
• R1 to R4 are each independently C1-C60 alkyl, C6-C60 aryl, or C2-C60 heteroaryl containing at least one heteroatom selected from the group consisting of O, N, S, Si and P;
• X1 and X2 are each independently halogen, C1-C30 alkyl, C1-C30 alkylcarboxylate, acetylacetonate, or C1-C30 hydrocarbyl containing at least one selected from among ether and amino;
• A is boron or aluminum;
• Y1 to Y4 are each independently fluorine-substituted C6-C60 aryl, fluorine-substituted C6-C60 heteroaryl containing at least one heteroatom selected from the group consisting of O, N, S, Si and P, fluorine-substituted C6-C60 aryloxy, or fluorine-substituted C6-C60 alkoxy;
• R11 is C4-C8 alkyl;
• and
• R22 is C1-C8 alkyl,
• wherein the alkyl, aryl or heteroaryl in R, R1 to R4, X1, X2, Y1 to Y4, R11, and R22 are optionally further substituted with at least one selected from among C1-C30 alkyl, C6-C30 aryl, C1-C30 alkoxy, mono(C1-C30)alkylamino, di(C1-C30)alkylamino, tri(C1-C30)alkylamino, mono(C6-C30)arylamino, di(C6-C30)arylamino, tri(C6-C30)arylamino, mono(C1-C30)alkylsilyl, di(C1-C30)alkylsilyl, tri(C1-C30)alkylsilyl, mono(C6-C30)arylsilyl, di(C6-C30)arylsilyl, and tri(C6-C30)arylsilyl.