Catalyst composition and process for di-, tri- and/or tetramerization of ethylene

A catalyst composition;

• obtained by combining at least;
• (a) a chromium compound;
• (b) a ligand of the general structure
• R1R2P—N(R3)—P(R4)—N(R5)—PR6R7,
• wherein R1, R2, R3, R4, R5, R6 and R7 are independently selected from halogen, amino, trimethylsilyl, C1-C10-alkyl, phenyl, benzyl, tolyl and xylyl;
• and
• (c) an activator or co-catalyst;
• wherein the concentration of the chromium compound is from 0.1 to 10 mmol/l;
• wherein the chromium compound is CrCl3(THF)3, Cr(III)acetylacetonate, Cr(III)octanoate, chromium hexacarbonyl, Cr(III)-2-ethylhexanoate or (benzene)tricarbonyl-chromium.