Methylene bridged metallocenes as olefin-polymerization catalyst components
View Patent ↗A new class of methylene-bridged metallocenes of formula (I), wherein M is a transition metal of group 3, 4, 5, 6, lanthanide or actinide; X is a monoanionic sigma ligand; R 1 can be alkyl, cycloalkyl, aryl, alkylaryl or arylalkyl radicals; R 2 can be halogen, alkyl, cycloalkyl, aryl, alkylaryl or arylalkyl radical; p is 0-3; m is 0-2; and n is 0-4. Furthermore, the corresponding ligands, a new process for their preparation and catalysts systems containing said methylene-bridged metallocenes are described.
1. A ligand of formula (II):
wherein the substituents R 1 and R 2 , the same or different from each other, are selected from the group consisting of linear or branched, C 1 -C 20 aliphatic hydrocarbon, C 3 -C 20 cycloalkyl, C 6 -C 20 aryl, C 7 -C 20 alkylaryl and C 7 -C 20 arylalkyl radicals, optionally containing one or more atoms belonging to groups 13-17 of the Periodic Table of the Elements, —OR, —SR, —NR 2 , N-pyrrolyl, N-indolyl, —PR 2 , —BR 2 and —SiR 3 groups; m is an integer ranging from 0 to 2; n is an integer ranging from 0 to 4; with the proviso that, when m is 0, then n is different from 0.
2. A process for the preparation of a ligand as described in claim 1 , comprising reacting formaldehyde or a derivative thereof with an indene of formula (III):
wherein R 1 , R 2 and n have the meaning reported in claim 1 , and q is 0 or 1, in the presence of a Brønsted acid, the molar ratio between said compound (III) and formaldehyde of a derivative thereof being ≧1.
3. The process according to claim 2 , characterized by being carried out in an aprotic solvent.
4. The process according to claim 3 , wherein said aprotic solvent is toluene or n-decane and said acid is selected from the group consisting of p-toluensulphonic acid, acetic acid, methanesulphonic acid, HCl, H 2 SO 4 , HBF 4 and mixtures thereof.
5. The process according to claim 2 , wherein said formaldehyde or a derivative thereof is selected from formalin, paraformaldehyde, 1,3-dioxolane and trioxane.
6. The process according to claim 2 , wherein the molar ratio between said indene of formula (III) and formaldehyde or a derivative thereof is about 2.