| abstract |
The present invention relates to a catalyst composition comprising: (a) a chromium compound; (b) a ligand of the following general structure (A) R1R2P-N(R3)-P(R4)-NR5R6, or (B) R1R2P -N(R3)-P(XR7)R8 or R1R2P-N(R3)-P(XR7)2, wherein X=O or S, wherein R1, R2, R3, R4, R5, R6, R7 and R8 are independently C1-C10-alkyl, C6-C20-aryl, C3-C10-cycloalkyl, aralkyl, alkylaryl or trialkylfluorenyl, or any of the cyclic derivatives of (A) and (B) Wherein at least one of the P or N atoms of the PNPN-unit or the PNP-unit is a member of the ring system, the ring system being formed by one or more constituent compounds of the structure (A) or (B) by substitution And (c) an activator or a secondary catalyst; and a method for tri- and/or tetrapolymerization. |