Transition metal compounds having a donor-acceptor interaction and a specific substitution pattern
The present invention relates to compounds in which a transition metal is complexed by at least two ligand systems and at least two of the systems are reversibly joined to one another by at least one bridge comprising a donor and an acceptor, wherein at least one fluorenyl ligand is present and at least one substituent on the acceptor group is an alkyl or aryl radical. The invention further relates to the use of these compounds having a donor-acceptor interaction as polymerization catalysts for preparing high molecular weight elastomers.
1. A process for the homopolymerization or copolymerization of one or more olefins, cycloolefins, isoolefins, alkynes or diolefins monomers comprising the step of admixing one or more monomer in the presence of at least one transition metal compounds having at least two ligands and at least one donor-acceptor interaction between the ligands, wherein at least one ligand is a fluorenyl ligand and the transition metal compound has at least one alkyl or aryl group on at least one acceptor atom and optionally one or more cocatalyst, wherein the process is carried out at a temperature from about −60 to about +250° C., wherein the process produces polymers having a mean viscosity molar mass M η greater than 500 kg/mol.
2. Process according to claim 1 , wherein the transition metal compounds are applied to a support material.
3. Process according to claim 1 , wherein the polymerization is carried out in the temperature range from 10° C. to 100° C.
4. Process according to claim 3 , wherein the polymerisation is carried out in the temperature range 20° to 90° C.
5. Process according to claim 4 wherein the polymerisation is carried out in the temperature range from 30° C. to 80° C.
6. Process according to claim 1 , wherein the ratio of cocatalyst to transition metal compound is in the range ≦100,000:1.
7. Process according to claim 6 , wherein the ratio of cocatalyst to transition metal compound is in the range ≦10,000:1.
8. Process according to claim 7 , wherein the ratio of cocatalyst to transition metal compound is in the range ≦1,000:1.
9. Process according to claim 8 , wherein the ratio of cocatalyst to transition metal compound is in the range ≦300:1.
10. A process for preparing an elastomer comprising the step of admixing one or more monomer in the presence of at least one transition metal compound having at least two ligands and at least one donor-acceptor interaction between the ligands, wherein at least one ligand is a fluorenyl ligand and the transition metal compound has at least one alkyl or aryl group on at least one acceptor atom and optionally one or more cocatalyst, wherein the process is carded out at a temperature from about −60 to about +250° C., wherein the process produces polymers having a mean viscosity molar mass Mη greater than 500 kg/mol.
11. A process for preparing a polyolefin comprising the step of admixing one or more monomer in the presence of at least one transition metal compound having at least two ligands and at least one donor-acceptor interaction between the ligands, wherein at least one ligand is a fluorenyl ligand and the transition metal compound has at least one alkyl or aryl group on at least one acceptor atom and optionally one or more cocatalyst, wherein the process is carried out at a temperature from about −60 to about +250° C., wherein the process produces polymers having a mean viscosity molar mass M η greeter than 500 kg/mol.
12. The process according to claim 10 , wherein the elastomer is an elastomeric polypropylene.
13. The process according to claim 10 , wherein the elastomer prepared is selected from the group consisting of ethylene-propylene-diene copolymers, ethylene-butene-diene copolymers, ethylene-hexene-diene copolymers, ethylene-octene-diene copolymers or mixtures thereof.
14. The process according to claim 10 , wherein the elastomer has long-chain branching.
15. The process according to claim 10 , wherein the elastomer prepared has bimodal or multimodal molecular weight distribution.
16. The process according to claim 11 , wherein the polyolefin has long-chain branching.
17. The process according to claim 11 , wherein the polyolefin has bimodal or multimodal molecular weight distribution.