Catalytic systems made of a complex of rare earths for stereospecific polymerisation of conjugated dienes

1. A catalytic polymerization system comprising:

(i) a rare-earth complex of Formula (II) Ln(A) 3 (B) n , in which

Ln is a rare-earth metal from the family of lanthanides or yttrium or scandium,

A is a ligand chosen from the family of organophosphates, the family of alcoholates, the family of amides, the family of alkyls, aryls or benzyls or the family of borohydrides,

B is a Lewis base selected from the group consisting of ethers, amines, phosphates, and thioethers, and

n is a number ranging from 1 to 3;

(ii) an alkylating agent;

(iii) a compound based on an aromatic ring and having at least two heteroatoms chosen from the elements O, N, S, P, and corresponding to the Formula (III):

wherein

the R groups are identical to or different from one another, and each represent either:

a hydrogen atom,

an aliphatic, cycloaliphatic or aromatic alkyl radical, optionally comprising one or several heteroatoms (N, O, P, S, Si) or one or more halogen atoms,

a halogen atom,

a group based on one or more heteroatoms (N, O, P, S, Si);

x and y are integers from 0 to 6;

D is a group having a chemical function, one of the atoms of which has a non-bonding pair;

L being an atom from column 1 of the Periodic Table.

2. The catalytic polymerization system according to claim 1 , wherein in Formula (II), Ln represents yttrium or gadolinium.

3. The catalytic polymerization system according to claim 1 , wherein the alkylating agent is chosen from triisobutylaluminium or diisobutylaluminium hydride.

4. The catalytic polymerization system according to claim 1 , wherein in Formula (III), L is an atom from column 1 of the Periodic Table chosen from hydrogen, lithium, sodium, or potassium.

5. The catalytic polymerization system according to claim 1 , wherein in Formula (III), D is a group having a function chosen from alcohol, amine, ether, imine, phosphine, thioether, or thiol functions.

6. The catalytic polymerization system according to claim 5 , wherein the compound of Formula (III) is chosen from those represented by Formula (IV):

wherein:

the R groups are identical to or different from one another, and each represent either:

a hydrogen atom,

an aliphatic, cycloaliphatic or aromatic alkyl radical, optionally comprising one or several heteroatoms (N, O, P, S, Si) or one or more halogen atoms,

a halogen atom,

a group based on one or more heteroatoms (N, O, P, S, Si);

x and y are integers from 0 to 6; and

wherein R 1 and R 2 , which are identical or different, are each a hydrogen atom or a C 1 -C 20 aliphatic, C 5 -C 20 cycloaliphatic or C 6 -C 20 aromatic alkyl radical.

7. The catalytic polymerization system according to claim 6 , wherein in Formula (IV), x and y are equal and have a value of 0.

8. The catalytic polymerization system according to claim 7 , wherein the compound of Formula (IV) is chosen from phenoxyimines of Formula (V):

in which R 1 and R 2 which are identical or different, are each a hydrogen atom or a C 1 -C 20 aliphatic, C 5 -C 20 cycloaliphatic or C 6 -C 20 aromatic alkyl radical and R 3 to R 6 are identical to or different from one another, and each represent either:

a hydrogen atom,

an aliphatic, cycloaliphatic or aromatic alkyl radical, optionally comprising one or several heteroatoms (N, O, P, S, Si) or one or more halogen atoms,

a halogen atom,

a group based on one or more heteroatoms (N, O, P, S, Si).

9. The catalytic polymerization system according to claim 8 , wherein the phenoxyimine of Formula (V) is chosen from N-phenyl-3,5-di-tert-butylsalicylaldimine or N-(2,6-diisopropyl)phenyl-3,5-di-tert-butylsalicylaldimine.

10. The catalytic polymerization system according to claim 1 , further comprising a preforming amount of a conjugated diene, thereby obtaining a preformed catalyst.

11. The catalytic polymerization system according to claim 1 , wherein a molar ratio of compound of Formula III to rare-earth metal has a value between 0 and 3.

12. The catalytic polymerization system according to claim 1 , wherein a molar ratio of alkylating agent to rare-earth metal has a value ranging from 2 to 40.

13. A process for preparing a catalytic system according to claim 1 , comprising:

reacting in situ in an inert hydrocarbon-based solvent comprising a monomer to be polymerized by the catalytic system:

the rare-earth complex,

the compound of Formula (III),

the alkylating agent, and also, where appropriate,

a halogen donor,

thereby providing said catalytic system.

14. A process for preparing a catalytic system according claim 1 , comprising:

directly premixing, in an inert hydrocarbon based solvent prior to contacting the monomer to be polymerized by the catalytic system:

the rare-earth complex,

the compound of Formula (III),

the alkylating agent, and also, where appropriate,

a halogen donor,

thereby obtaining said catalytic system.

15. A process for preparing a catalytic system according to claim 6 , comprising:

combining, in an inert hydrocarbon-based solvent:

the rare-earth complex,

the compound of Formula (IV),

the alkylating agent, and also, where appropriate,

a halogen donor, and

a preforming amount of a conjugated diene, thereby obtaining a preformed catalytic system.

16. A process for preparing a diene elastomer having a content of cis-1,4 linkages substantially greater than 90%, comprising:

reacting in a continuous or batch reaction a catalytic system in an inert hydrocarbon-based solvent with at least one conjugated diene monomer to be polymerized, wherein said catalytic system is as defined in claim 1 .

17. A process for preparing a polymer according to claim 16 , wherein said monomer is chosen from butadiene or isoprene.

18. A catalytic polymerization system comprising:

(i) a rare-earth complex of Formula (II) Ln(A) 3 (B) n , in which

Ln is a rare-earth metal from the family of lanthanides or yttrium or scandium,

A is a ligand chosen from the family of amides,

B is a Lewis base selected from the group consisting of ethers, amines, phosphates, and thioethers, and

n is a number ranging from 0 to 3;

(ii) an alkylating agent;

(iii) a compound based on an aromatic ring and having at least two heteroatoms chosen from the elements O, N, S, P, and corresponding to the Formula (III):

wherein

the R groups are identical to or different from one another, and each represent either:

a hydrogen atom,

an aliphatic, cycloaliphatic or aromatic alkyl radical, optionally comprising one or several heteroatoms (N, O, P, S, Si) or one or more halogen atoms,

a halogen atom,

a group based on one or more heteroatoms (N, O, P, S, Si);

x and y are integers from 0 to 6;

D is a group having a chemical function, one of the atoms of which has a non-bonding pair;

L being an atom from column 1 of the Periodic Table.

19. The catalytic polymerization system according to claim 18 , wherein in Formula (II), A is a ligand chosen from N,N-bis[(trialkylsilyl)alkyl]amides.

20. The catalytic polymerization system according to claim 18 , wherein in Formula (II), A is N,N-bis(trimethylsilyl)amide.

21. A catalytic polymerization system comprising:

(i) a rare-earth complex of Formula (II) Ln(A) 3 (B) n , in which

Ln is a rare-earth metal from the family of lanthanides or yttrium or scandium,

A is a ligand chosen from the family of organophosphates, the family of alcoholates, the family of amides, the family of alkyls, aryls or benzyls or the family of borohydrides,

B is a Lewis base selected from the group consisting of ethers, amines, phosphates, and thioethers, and

n is a number ranging from 1 to 3;

(ii) an alkylating agent;

(iii) a compound based on an aromatic ring and having at least two heteroatoms chosen from the elements O, N, S, P, and corresponding to the Formula (III):

wherein

the R groups are identical to or different from one another, and each represent either:

a hydrogen atom,

an aliphatic, cycloaliphatic or aromatic alkyl radical, optionally comprising one or several heteroatoms (N, O, P, S, Si) or one or more halogen atoms,

a halogen atom,

a group based on one or more heteroatoms (N, O, P, S, Si);

x and y are integers from 0 to 6;

D is a group having a chemical function, one of the atoms of which has a non-bonding pair;

L being an atom from column 1 of the and Periodic Table further comprising a halogen donor compound.

22. The catalytic polymerization system according to claim 21 , wherein the halogen donor is a dialkylaluminium halide.

23. A catalytic polymerization system comprising:

a rare-earth complex of Formula (II) Ln(A) 3 (B) n , in which

Ln is a rare-earth metal from the family of lanthanides or yttrium or scandium,

A is a ligand chosen from the family of organophosphates, the family of amides, the family of alkyls, aryls or benzyls or the family of borohydrides,

B is a Lewis base selected from the group consisting of ethers, amines, phosphates, and thioethers, and

n is a number ranging from 0 to 3;

(ii) an alkylating agent;

(iii) a compound based on an aromatic ring and having at least two heteroatoms chosen from the elements O, N, S, P, and corresponding to the Formula (III):

wherein

the R groups are identical to or different from one another, and each represent either:

a hydrogen atom,

an aliphatic, cycloaliphatic or aromatic alkyl radical, optionally comprising one or several heteroatoms (N, O, P, S, Si) or one or more halogen atoms,

a halogen atom,

a group based on one or more heteroatoms (N, O, P, S, Si);

x and y are integers from 0 to 6;

D is a group having a chemical function, one of the atoms of which has a non-bonding pair;

L being an atom from column 1 of the Periodic Table.