Process for preparing polymers from 3-methylbut-1-ene

1. A process for preparing at least one copolymer comprising propene as a monomer and 3-methylbut-1-ene as a comonomer, the process comprising:

copolymerizing a reaction mixture comprising propene and 3-methylbut-1-ene in the presence of a catalyst of formula (I)

and aluminum-comprising compound or boron-comprising compound as a cocatalyst, to obtain the copolymer,

wherein a proportion of the 3-methylbut-1-ene in the copolymer is 1 to 10 mol %,

wherein the copolymer has a melting point of 90 to 125° C.,

wherein the copolymer has a molar mass of 6500 to 8500, and

wherein, in the catalyst of formula (I)

Cp* is selected from the group consisting of a substituted cyclopentadienyl, an unsubstituted cyclopentadienyl, a substituted indenyl, an unsubstituted indenyl, a substituted tetrahydroindenyl, an unsubstituted tetrahydroindenyl, a substituted octahydrofluorenyl, an unsubstituted octahydrofluorenyl, a substituted flourenyl, and an unsubstituted fluorenyl group,

Y is selected from the group consisting of a substituted cyclopentadienyl, an unsubstituted cyclopentadienyl, a substituted indenyl, an unsubstituted indenyl, a substituted tetrahydroindenyl, an unsubstituted tetrahydroindenyl, a substituted octahydrofluorenyl, an unsubstituted octahydrofluorenyl, a substituted flourenyl, an unsubstituted fluorenyl group, or an anionic ligand group comprising nitrogen, phosphorus, oxygen, or sulfur, and up to 20 atoms which are not hydrogen,

or Cp* and Y are joined to one another covalently or via a Z group,

wherein Z is boron or a group which comprises an element of group 14 of the Periodic Table of the Elements, and has up to 20 atoms which are not hydrogen atoms,

M is a metal of group 3 to 10, with the exception of scandium, or of the lanthanoids, of the Periodic Table of the Elements,

X is in each case independently a halogen atom, a pseudohalogen, a hydrogen atom, a silyl group, a phosphide, a sulfide, or an organic radical, and

m is a number which is sufficient to saturate the valences of M with the X, an aluminum- or boron-comprising compound as a cocatalyst.

2. The process of claim 1 , wherein the catalyst is a catalyst of formula (Ia)

3. The process of claim 2 , wherein the catalyst comprises a catalyst wherein Z is a CR 2 R 3 group or an SiR 2 R 3 group, wherein R 2 and R 3 are the same or different and are each hydrogen, an aromatic radical, or an aliphatic radical.

4. The process of claim 1 , wherein the aluminum-comprising compound is present, and is methylaluminoxane (MAO).

5. The process of claim 1 , wherein the copolymerizing is performed at a molar ratio of metal of the catalyst of the formula (I) to aluminum or boron of the cocatalyst of 1:0.1 to 1:100 000.

6. The process of claim 1 , wherein the copolymerizing is performed at a molar ratio of monomers to catalyst of formula (I) of 1×10 10 :1 to 100:1.

7. The process of claim 1 , wherein the copolymerizing is performed in a solvent selected from the group consisting of butane, hexane, heptane, toluene, xylene, and ethylbenzene.

8. The process of claim 1 , wherein the copolymerizing is performed at a temperature of −30° C. to 250° C.

9. The process of claim 1 , wherein the copolymerizing is performed at a pressure of 0.1 to 1 MPa.

10. The process of claim 1 , wherein a molar proportion of 3-methylbut-1-ene monomer in the reaction mixture in the sum of monomers of 3-methylbut-1-ene and ethene and propene is at least 20%.

11. The process of claim 1 , wherein a proportion of 3-methylbut-1-ene monomer in the reaction mixture in the sum of monomers of 3-methylbut-1-ene and ethene and propene is 40 to 80%.

12. The process of claim 1 , wherein, in the catalyst of formula (I),

Cp* and Y are the same or different and are each selected from the group consisting of a cyclopentadienyl group, an indenyl group, and a fluorenyl group,

Z is a hydrocarbon group,

M is a metal of group 4 of the Periodic Table of the Elements,

X is a halogen, and

m is two.

13. The process of claim 1 , wherein the catalyst of formula (I) has formula (II)

14. The process of claim 1 , wherein, in the catalyst of formula (I),

Cp* is a cyclopentadienyl group substituted by 1 to 4 methyl groups,

Y is a nitrogen-comprising group,

Z is a silicon-comprising group,

M is a metal of group 4 of the Periodic Table of the Elements,

X is a halogen, and

m is two.

15. The process of claim 14 , wherein, in the catalyst of formula (I) has formula (IV)

16. The process of claim 1 , wherein the 3-methylbut-1-ene is obtained by

a) hydroformylating isobutene to 3-methylbutanal,

b) hydrogenating the 3-methylbutanal to 3-methylbutanol, and

c) eliminating water from 3-methylbutanol,

wherein the 3-methylbut-1-ene obtained from the eliminating c) is added to the reaction mixture directly without performing a chemical purification.

17. The process of claim 1 , wherein the copolymerizing is performed at a temperature of 50° C. to 80° C.

18. The process of claim 1 , wherein the catalyst of formula (I) has formula (III)

19. The process of claim 1 , wherein the catalyst of formula (I) has formula (V)

20. The process of claim 1 , wherein, in the catalyst of formula (I),

Cp* and Y are the same or different and are each selected from the group consisting of a cyclopentadienyl group, an indenyl group, and a fluorenyl group,

Z is a hydrocarbon group,

M is a metal of group 4 of the Periodic Table of the Elements,

X is a chlorine, and

m is two.