| abstract |
An olefin oligomerization catalyst comprising a product of the reaction among (A) a nickel compound, (B) an organophosphorus compound, (C) an organoaluminum compound, and (D) a specific compound having a carbon-halogen linkage, a specific oxo-acid or its salt, a specific sulfonic acid or its salt, or a compound represented by any of the general formulae: QX4n, QRn, QR'n, QX4nR'm, QR1R'm, Q1(BR4)p and R"(BR4), wherein Q is an element selected from among Mg, Ti, Zr, B and Sn; Q1 is an element selected from among Li, Na, K, Ca and Zn; X4 is halogen or hydrogen; R is C1-C12 hydrocarbyl; R' is oxygenous C1-C12 hydrocarbyl; R" is C1-C20 hydrocarbyl or ammonium; n is the valency of Q; 1 and m are natural numbers satisfying the relationship: n = 1 + m; and p is the valency of Q1. This catalyst is useful in the preparation of .alpha.-olefin oligomers. |