WO2001007491A1

WO2001007491A1 - Method for preparing olefin (co)polymers

Info

Publication number: WO2001007491A1
Application number: PCT/EP2000/006559
Authority: WO
Inventors: Gerrit Luinstra; Gerald Werne; Ursula Rief; Marc Oliver Kristen; Joachim Queisser; Michael GEPRÄGS
Original assignee: Basf Aktiengesellschaft
Priority date: 1999-07-27
Filing date: 2000-07-11
Publication date: 2001-02-01

Abstract

The present invention relates to a method for preparing α-olefins homopolymers or copolymers that involves reacting the starting monomer or monomers in the presence of one or more transition metal compounds of the general formula (I) and in the presence of a cocatalyst consisting of a potent neutral Lewis acid, of an ionic compound having a cation consisting of a Lewis acid or of an ionic compound having a Brönsted acid in the form of a cation. In the formula (I), the substituents and indices are as follow: R?1 and R2¿ are C¿4?-C16 heteroaryl or C6-C16 aryl with halogeno, nitro, cyano, sulfonato or trihalogenmethyl substituents in both ortho-positions relative to the binding site between aryl and heteroaryl and N?a and Nb; R3 and R4¿ are hydrogen, C¿1?-C10 alkyl, C3-C10 cycloalkyl, C6-C16 aryl, alkylaryl with 1 to 10 carbon atoms in the alkyl portion and 6 to 14 carbon atoms in the aryl portion or Si(R?8)¿3; R8 is C1-C10 alkyl, C3-C10 cycloalkyl, C6-C16 aryl, alkylaryl with 1 to 10 carbon atoms in the alkyl portion and 6 to 14 carbon atoms in the aryl portion; R?5, R6 and R7¿ are hydrogen, C¿1?-C10 alkyl, C3-C10 cycloalkyl, C6-C16 aryl, alkylaryl with 1 to 10 carbon atoms in the alkyl portion and 6 to 14 carbon atoms in the aryl portion, Si(R?8)¿3 or functional groups selected among the elements from the groups IVA to VIIA of the classification table or R?5 and R6¿ and/or R?6 and R7¿ form together a ringed five-, six- or seven-membered aliphatic or aromatic substituted or non-substituted carbon or hetero cycle; M is Fe, Ru, Co or Rh;; T and Q are neutral or monoanionic monodentate ligands; A is a non-coordinating or hardly coordinating anion; m and p are 0, 1, 2 or 3; and q and n are 1, 2 or 3.

Description

Process for the production of olefin (co) polymers

description

The present invention relates to a process for the production of homopolymers from α-olefins and to a process for the production of copolymers from α-olefins. Furthermore, the invention relates to the copolymers obtainable by the latter method. The invention also relates to transition metal compounds and catalyst systems and their use for olefin (co) polymerization.

Processes for olefin polymerization are known to the person skilled in the art. In addition to polyolefin syntheses using Ziegler / Natta catalysis, polymerisation-active transition metal complexes based on Group IVB metals of the Periodic Table of the Elements in the form of metallocene or half-sandwich complexes have been of increasing interest in research and technology (see also HH Brintzinger, D Fischer, R. Mülhaupt, B. Rieger,

R.M. Waymouth, Angew. Chem. Int. Ed. Engl. 1995, 34, 1143-1170).

Brookhart et al., J. Am. Chem. Soc. 1995, 117, 6414-6415, were able to show that complexes of the late transition metals palladium and nickel are also suitable for the homopolymerization of α-olefins if a bidentate bisiminchelate ligand with sterically demanding phenyl radicals on the imine nitrogen atoms is used. However, high activities could only be achieved for the ethene polymerization with nickel complexes, while the palladium-catalyzed homopolymerizations, on the other hand, provided only moderate activities. With these palladium and nickel compounds chelated with vicinal bisimine ligands, Brookhart et al., J. Am. Chem. Soc. 1996, 118, 267-268 and J. Am. Chem. Soc. 1998, 120, 888-899, also to copolymerize ethene and α-olefins with polar groups such as methyl acrylate, t-butyl acrylate or methyl vinyl ketone. However, the incorporation rates of the polar comonomer and the polymerization activities were very low. Highly active catalysts for the homopolymerization of ethene, which are comparable in their activity to the metallocene systems, are new types with neutral tridentate

2, 6-bis (imine) pyridine ligands represent chelated, five-coordinate iron complexes (see also Gibson et al., Chem. Commun. 1998, 849-850 and Angew. Chem. 1999, 111, 448-468). The effectiveness of this catalyst system in the homopolymerization of ethene in turn essentially depends on the imine nitrogen atoms of the bisimine ligand containing sterically demanding aryl radicals, ie those with bulky substituents in the ortho positions. have (see Brookhart et. al., J. Am. Chem. Soc. 1998, 120, 4049-4050 regarding). The iron compounds chelated with these tridentate bisimine ligands yield high molecular weight linear polyethylene in the presence of ethene, isotactic polypropylene in the presence of propene (see also Gibson et. Al., Chem. Commun. 1998, 849-850 and Pellecchia et al., Macromol. Rapid Commun. 1998, 19, 651-655), where the activity of the propene polymerization drops sharply compared to that of the ethene polymerization (see also WO 98/30612).

WO 98/27124 describes polymerizations of ethene with complexes of iron and cobalt, which are chelated with tridentate bisimine ligand systems as mentioned above. The polymerizations carried out with these iron chelate complexes provide polymer material which is very inhomogeneous in its composition and is characterized by very broad molecular weight distributions. Only very moderate activities are achieved, for example, if appropriate cobalt complexes are used whose tridentate bisiminchelate ligands have aryl residues on the imine nitrogen which are substituted in one of the ortho positions with a halogen such as chlorine.

Information on the homo- or copolymerization of α-olefins other than ethene or propene, i.e. No higher α-olefins have been described so far, although these (co) polymers could be of interest for technical applications.

It would therefore be desirable to be able to use a transition metal compound or a catalyst system which homo- and copolymerizes α-olefins with high activity to form a uniform product. It would also be desirable to easily obtain olefin copolymers in good yields that can be easily processed and are suitable for toughening.

The present invention was therefore based on the object of providing processes for the production of olefin (co) polymers which also convert higher α-olefins in satisfactory yields or with high polymerization activity into homopolymeric products with a narrow molecular weight distribution. Furthermore, the invention was based on the object of making accessible olefin copolymers which can be easily processed and which also have a very high degree of uniformity, ie a very narrow molecular weight distribution. Accordingly, we have found a process for the preparation of homopolymers from α-olefins, in which the starting monomer is present in the presence of a transition metal compound (I) of the general formula

in which the substituents and indices have the following meaning:

R ¹ , R ² C ₆ to C ₆ aryl with halogen, nitro, cyano, sulfonato or trihalomethyl substituents in the two ortho positions to the N ^a and N ^b aryl bond,

R ³ , R ^{4 are} hydrogen, Ci- to Cio-alkyl, C ₃ - to -CC ₀ cycloalkyl, C ₆ - to Ci ₆ ~ aryl, alkylaryl with 1 to 10 carbon atoms in the

Alkyl and 6 to 14 carbon atoms in the aryl part or Si (R ⁸ ) ₃ with

R ^Ö Cι ~ to Cio-alkyl, C - to -Cι ₀ -cycloalkyl, C ₆ - to Ci ₆ -aryl, alkylaryl with 1 to 10 carbon atoms in the alkyl and 6 to 14 carbon atoms in the aryl part,

R ^5, R ^6, R ⁷ are hydrogen, Cι ~ to ₀ alkyl, C ₃ - to Cι ₀ cycloalkyl, C ₆ - to C _ß -aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl and 6 to 14 carbon atoms in the aryl part or Si (R ⁸ ) ₃ or functional groups based on the elements of groups IVA to VIIA of the periodic table of the elements or R ⁵ and R ⁶ and / or R ⁶ and R ⁷ together form a fused five -, six- or seven-membered aliphatic or aromatic, substituted or unsubstituted carbo- or heterocycle,

M Fe, Ru, Co or Rh,

T, Q neutral or monoanionic monodentate ligands,

a non or poorly coordinating anion, m, p 0, 1, 2 or 3,

q 1, 2 or 3 and

n 1, 2 or 3

and a strong neutral Lewis acid, an ionic compound with a Lewis acidic cation or an ionic compound with a Bronsted acid as a cation is polymerized as a cocatalyst.

Furthermore, it was found that α-olefins can be copolymerized in the presence of the transition metal compound (I) and the aforementioned cocatalyst.

In addition, the transition metal compound (I) and a catalyst system containing the essential constituents of the transition metal compound (I) and a strong neutral Lewis acid, an ionic compound with a Lewis acid cation or an ionic compound with a Bronsted acid as a cation were found as cocatalysts , Finally, the use of the aforementioned transition metal compounds or catalyst systems for the (co) polymerization of α-olefins was found.

Linear or branched hydrocarbons having two to 26 carbon atoms are suitable as α-olefins in the context of the present invention. In addition to the terminal double bond, these α-olefins can have one, two or more further double and / or triple bonds. Suitable α-olefins are, for example, ethene, propene, 1-butene, i-butene, 1, 3-butadiene, 1-pentene, 3-methyl- or 4-methyl-1-pentene, 1-hexene, 3- , 4- or 5-methyl-l-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-dodecadecene, 1-hexadecene or 1-eicosen.

For the homopolymerization of α-olefins according to the process according to the invention, preference is given to using ethene and propene and also preferably 1-butene, i-butene, 1-pentene, 1-hexene or 1-octene.

In the copolymerization of α-olefins according to the invention, any binary, ternary or higher mixtures of the aforementioned α-olefins can be used. Binary polymerization mixtures can contain, for example, ethene and propene, i-butene, i-butene, 1-pentene, 1-hexene or 1-octene as starting monomers. Binary mixtures based on Propene and i-butene, i-butene, 1-pentene or 1-hexene and mixtures of i-butene with i-butene, 1-pentene or 1-hexene.

Particularly suitable among the binary starting mixtures are ethene / propene, ethene / 1-butene, ethene / 1-pentene and ethene / 1-hexene. A binary mixture of ethene and 1-hexene is preferred.

Suitable ternary starting mixtures are composed, for example, of ethene and propene and also i-butene, i-butene, 1-pentene, 1-hexene or 1-octene. Mixtures of ethene and 1-butene and, as a third comonomer, 1-pentene, 1-hexene or 1-octene are also suitable. Preferred among the ternary α-olefin mixtures are those of ethene, propene and 1-butene and of ethene, propene and 1-hexene.

The starting monomers mentioned are transition-metal catalyzed by the processes according to the invention in the presence of one or more complex compounds of the general formula (I)

converted to homo- or copolymers.

The radicals R ¹ and R ² in (I) represent C ₆ - to -C ₆ aryl groups, which are each substituted in their two ortho positions N and N _& with electron-withdrawing radicals such as halogeno, cyano, nitro, sulfonato or trihalomethyl.

S0 ₃ R ⁶ , S0 ₃ Si (R ⁶ ) and S0 ₃ ⁺ (HN (R ⁵ ) ₃ ) ^_ are particularly suitable among the sulfonate residues. S0 ₃ Me, S0 ₃ SiMe ₃ and S0 ₃ ^_ (HNEt ₃ ) ⁺ are particularly suitable among these. Among the trihalomethyl residues, trifluor, trichlor and tribromomethyl, in particular trifluoromethyl, are particularly suitable. Particularly suitable ortho substituents are halogen radicals such as the fluorine, chlorine, bromine or iodine radical. Chlorine or bromine residues are preferably used as ortho substituents. Furthermore, the respective ortho positions are preferably occupied by identical residues. In addition to the ortho radicals, the aryl radicals R ¹ and R ² can have one or more further substituents. Examples of such substituents are functional groups based on the elements from groups IVA, VA, VIA and VIIA of the Periodic Table of the Elements. Suitable are, for example, straight or branched C ± - to Cio-alkyl, preferably Cι ~ to C ₆ alkyl, such as methyl, ethyl, n- or i-propyl, n-, i- or t-butyl, partially or perhalogenated Cι ~ to -C ₀ alkyl, preferably C ~ ~ to Cβ-alkyl, such as trifluoro or trichloromethyl or 2, 2, 2-trifluoro-ethyl, triorganosilyl, such as trimethyl, triethyl, tri-t-butyl, triphenyl or t -Butyl-diphenylsilyl, the nitro, cyano or sulfonato group, amino, for example NH ₂ , dimethylamino, di-i-propylamino, di-n-butylamino, diphenylamino or dibenzylamino, Cι ~ to Cio-alkoxy, preferably Cι ~ to C ₆ -alkoxy, such as methoxy, ethoxy, i-propoxy or t-butoxy, or halogen, such as fluoride, chloride, bromide or iodide.

Preferred among the ortho-substituted aryl radicals are phenyl, naphthyl and anthracenyl groups, phenyl and naphthyl groups are particularly preferred and the phenyl group is particularly preferred. These ortho-substituted aryl radicals can also be substituted in the positions which are not ortho-permanent with functional groups based on the elements from groups IVA, VA, VIA and VIIA of the periodic table of the elements, as described above , An ortho-substituted phenyl radical R ¹ , R ² is preferably an additional substitution in the para position, for example with a methyl, t-butyl, chlorine or bromine radical. Preferred aryl radicals R ¹ , R ² are 2,6-dibromo, 2,6-dichloro, 2,6-dibromo-4-methyl- or 2,6-dichloro-4-methylphenyl.

The radicals R ³ and R ⁴ in (I), are hydrogen, Cι ~ to ₀ alkyl, C ₃ - to Cio-cycloalkyl, C ₆ - to C ₆ ~ aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl and 6 to 14 carbon atoms in the aryl part or a silyl radical (Si (R ⁸ ) ₃ ). Among the radicals R ³ and R ⁴ are hydrogen, methyl, ethyl, i-propyl, t-butyl, trifluoromethyl, phenyl, naphthyl , Tolyl, 2-i-propylphenyl, 2-t-butylphenyl, 2, 6-di-i-propylphenyl, 2-trifluoromethylphenyl, 4-methoxyphenyl, pyridyl or benzyl and especially hydrogen, methyl, ethyl, i-propyl or t- Preferred butyl.

The radicals R ⁵ , R ⁵ , R ^{7 are} independently hydrogen, Ci- to Cio-alkyl, C ₃ - to Cio-cycloalkyl, Cs ~ to -C ₆ aryl, alkylaryl with 1 to 10 carbon atoms in the alkyl and 6 to 14 carbon atoms an aryl part or a silyl radical (Si (R ⁸ ) ₃ ) or a functional group based on the elements of the groups VA to VIIA of the periodic table of the elements. Suitable functional groups are for example amino, such as NH ₂ , dimethylamino, di-i-propylamino, di-n-butylamino, diphenylamino or dibenzylamino, Cι ~ to Cio-alkoxy, preferably Cι ~ to C _δ alkoxy, for example methoxy, ethoxy, n- or i-propoxy, n-, i- or t-butoxy, or halogen such as fluoride, chloride, bromide or iodide.

R ⁵ and R ⁶ or / and R ⁶ and R ⁷ can also, together with the pyridyl system, form a fused five-, six- or seven-membered aliphatic or aromatic, substituted or unsubstituted carbo- or heterocycle, for example a substituted or unsubstituted one Isoquinoline system.

The radicals R ⁵ , R ⁶ , R ⁷ are preferably hydrogen or methyl, in particular hydrogen.

The radicals R ⁸ are C 1 -C 10 -alkyl, preferably C 1 -C 6 -alkyl, C ₆ -C 1 -C ₆ aryl, preferably C ₆ -C 10 -aryl, or alkylaryl with 1 to 10, preferably 1 to 6 C. -Atoms in alkyl and 6 to 14, before - adds 6 to 10 carbon atoms in question. Suitable residues are, for example, triorganosilyl residues such as trimethyl, triethyl, triphenyl or t-butyldiphenylsilyl.

Unless expressly stated otherwise elsewhere, the radicals R ³ to R ⁸ include the following alkyl, cycloalkyl, aryl and alkylaryl groups:

C 1 -C 10 -alkyl radicals preferably include, for example, the methyl, ethyl, n- or i-propyl, n-, i- or t-butyl group and the pentyl, hexyl or heptyl group in straight-chain and branched form. C 1 -C 1 -alkyl radicals also include those which are substituted by functional groups based on the elements of groups IVA, VA, VIA or VIIA of the periodic table, for example partially or perhalogenated alkyl radicals such as trichloromethyl, trifluoromethyl, 2, 2 , 2-trifluoroethyl, pentafluoroethyl or pentachloroethyl as well as alkyl radicals carrying one or more epoxy groups, for example propenoxy. Among the C ~ ~ to Cio-alkyl radicals, the C ~ ~ C ₆ alkyl radicals are regularly preferred.

Under suitable C ₃ - to Cio-cycloalkyl carbonyl fall as well as heterocycles, that is, for example, substituted and unsubstituted cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclo octyl, pyrrolyl, pyrrolidonyl or piperidinyl. Examples of substituted cycloaliphatic radicals include 1-methylcyclohexyl, 4-t-butylcyclohexyl and 2,3-dimethylcyclopropyl. Suitable C ₆ - to Ciβ-aryl groups generally include substituted and unsubstituted aryl radicals. Among the unsubstituted aryl radicals, the C 1 -C 10 -aryl groups such as phenyl and naphthyl are preferred. Phenyl is particularly preferred. In the case of the unsubstituted as well as the substituted C _δ ~ to Cig aryl groups, the indication of the carbon atoms (for example C ₆ -, Cχo or Ci ₆ ~) indicates the number of carbon atoms which form the aromatic system. Carbon atoms from possible alkyl and / or aryl substituents are not yet covered by this information. The statement C ₆ - to C ₆ aryl should therefore also include, for example, substituted C ₆ to C ₆ aryl residues such as substituted anthracenyl. C ₆ to C ₆ aryl radicals accordingly also include those radicals which are single, multiple or per-substituted with functional groups based on the elements from groups IVA, VA, VIA and VIIA of the periodic table of the elements. Suitable functional groups are -C ~ to Cio-alkyl, preferably Cι ~ to C _δ- alkyl, C _δ ~ to Cie-aryl, preferably Cδ ~ to Cio-aryl, triorganosilyl such as trimethyl, triethyl, triphenyl or t -Butyl-diphenylsilyl and amino, for example NH, dimethylamino, di-i-propylamino, di-n-butylamino, diphenylamino or dibenzylamino, Cι ~ to Cio-alkoxy, preferably Cι ~ to C ₆ -alkoxy, for example methoxy, Ethoxy, n- or i-propoxy, n-, i- or t-butoxy, or halogen such as fluoride, chloride, bromide or iodide.

C ₆ - to Ci _δ- aryl radicals are also to be understood as meaning substituted and unsubstituted heteroaryl radicals with respect to the substituents R ³ to R ⁸ , for example C - to C ₃ heteroaryl, preferably C ₄ - to Cg heteroaryl, such as pyridyl, pyrimidyl, quinolyl or isoquinylyl.

Suitable alkylaryl radicals R ³ to R ⁸ generally include those having 1 to 10, preferably 1 to 6, carbon atoms in the alkyl and 6 to 14, preferably 6 to 10, carbon atoms in the aryl part, in particular the benzyl group.

The metals M in (I) are the elements iron, cobalt, ruthenium or rhodium. In the transition metal compounds (I), iron, cobalt and ruthenium are generally formally charged twice or three times positively, and rhodium is usually given a formally single or triple positive charge. Preferred among the

Metals M are cobalt and iron, iron is particularly preferred.

T and Q represent neutral and / or monoanionic ligands. Lewis bases are suitable as neutral ligands, for example acetonitrile, benzonitrile, diethyl ether, tetrahydrofuran, amines, phosphines, ethyl acetate, dimethyl sulfoxide, dimethylformamide or hexamethylphosphoric acid triamide. As a Lewis basic Neutral ligand is also suitable for ethene. Monoanionic ligands are, for example, carbanions based on substituted or unsubstituted alkyl, aryl or acyl radicals or halide ions.

The radical T in (I) preferably denotes chloride, bromide, iodide, methyl, phenyl, benzyl or a C 1 to C 1 alkyl which has no hydrogen atoms in the β position to the metal center M and has a C 1 -C 4 -alkyl ester- or has a nitrile end group. Chloride and bromide are particularly preferred as halides and methyl as the alkyl radical.

The radical Q preferably represents acetonitrile, benzonitrile, ethene, tri-phenylphosphine as monodentate phosphorus compound, pyridine as monodentate aromatic nitrogen compound, acetate, propionate or butyrate, in particular acetate as a suitable carboxylate, a linear alkyl ether, for example a linear di-C - to C _δ Alkyl ethers such as diethyl ether or di-i-propyl ether, preferably diethyl ether, a cyclic alkyl ether such as tetrahydrofuran or dioxane, preferably tetrahydrofuran, a linear C 1 -C 4 -alkyl ester, for example ethyl acetate, dimethyl sulfoxide, dimethylformamide, hexamethylphosphoric acid triamide or an imide In the case of iron complexes (I) (M = Fe), Q is preferably a halide, for example a chloride or bromide, in the case of cobalt complexes (M = Co), Q is preferably chloride.

A non-coordinating or poorly coordinating anion A is to be understood according to the invention to mean those anions whose charge density at the anionic center is reduced due to electronegative residues and / or whose residues sterically shield the anionic center. Suitable anions A include antimonates, sulfates, sulfonates, borates, phosphates or perchlorates such as B [C ₆ H ₃ (CF ₃ ) ₂ ] ₄ ^~ (tetrakis (3, 5-bis (trifluoromethyl) phenyDborate), B [C _δ F ₅ ] ₄ - or BF ₄ - and SbF ₆ ", A1F ₄ -, AsF ₆ ^~ , PF ₆ " or trifluoroacetate (CF ₃ SO ₃ -). B [C _δ H ₃ (CF ₃ ) ₂ ] ₄ are preferred "SbF ₆ ^~ and PF ₆ ^~ . Borates, in particular B [C _δ H ₃ (CF)] ₄ -, are particularly preferred. Suitable non-coordinating or poorly coordinating anions and their preparation are described, for example, by SH Strauss, Chem. Rev. 1993, 93, pp. 927-942, as well as with W. Beck and K. Sünkel, Chem. Rev. 1988, 88, pp. 1405 - 1421.

Preferred transition metal compounds (I) are, for example: 2,6-bis [1- (2,6-dichlorophenylimino) ethyl] pyridine-iron (II) chloride, 2,6-bis [1- (2,6-dichloro- 4-methylphenylimino) ethyl] pyridine-iron (II) chloride, 2,6-bis [1- (2,6-dibromophenylimino) ethyl] yridine-iron (II) chloride, 2,6-bis [1- (2,6-dibromo-4-methylphenylimino) ethyl] pyridine-iron (II) chloride and the corresponding iron (II) bromide and cobalt (II) chloride complexes.

As an essential structural element, the transition metal compounds (I) have a tridentate bisimine chelate ligand (in formula (I) the structural element which is obtained with the components M, T, Q and A omitted). These tridentate ligands can e.g. can be obtained from 2,6-diacetylpyridine by reaction with primary amines such as 2,6-dibromaniline, 2,6-dichloroaniline, 2,6-dibromo-4-methylphenylamine or 2,6-di-chloro-4-methylphenylamine ( see J. Org. Chem. 1967, 32, 3246).

The transition metal compounds (I) can be according to a Brookhart et al. in Macromolecules 32, 2120-2130 (1999) described methods can be synthesized.

As a further component, the catalyst system according to the invention contains, as cocatalyst, a strong neutral Lewis acid, an ionic compound with Lewis acid cations or an ionic compound with a Bronsted acid as cation.

Suitable ionic compounds with Lewis acid cations fall e.g. under the general formula

G ¹⁺ (TX ¹ X ² X ³ X "(Ha),

in the

G is an element of the 1st or 2nd main group of the periodic table of the elements, such as lithium, sodium, potassium,

Rubidium, cesium, magnesium, calcium, strontium or barium, in particular lithium or sodium, or a silver, carbonium, oxonium, ammonium, sulfonium or 1,1 '-dimethylferrocenyl cation,

T an element of III. Main group of the periodic table of the elements means, in particular boron, aluminum or galium, preferably boron,

X ¹ to X ⁴ independently of one another for hydrogen, linear or branched Ci- to Cio-alkyl, preferably Cι ~ to Cs-alkyl, such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t -Butyl or n-hexyl, mono- or polysubstituted Ci to Cio-alkyl, preferably C ~ to Cg-alkyl, for example with halogen atoms such as fluorine, chlorine,

Bromine or iodine, to Cδ- Ciδ-aryl, preferably C _δ ~ to co-aryl, for example phenyl, which may also be mono- or polysubstituted sub- may be substituted, for example with halogen atoms such as fluorine, chlorine, bromine or iodine, for example pentafluorophenyl, alkylaryl with 1 to 10 C atoms, preferably 1 to 6 C atoms in the alkyl radical and 6 to 14 C atoms, preferably 6 up to 10 carbon atoms in the aryl radical, for example benzyl, fluorine,

Chlorine, bromine, iodine, -C ~ to Cio-alkoxy, preferably Cι ~ to Cβ-alkoxy, such as methoxy, ethoxy or i-propoxy, or Cς, - to Ci _δ aryloxy, preferably C ₆ - to Cι ₀ aryloxy, eg phenoxy, and

1 or 2 means.

The anion (TX ¹ X ² X ³ X ⁴ ) - in a compound of the general formula (Ha) - is preferably a non-coordinating counterion. For example, boron compounds such as those in WO 91/09882, to which express reference is made here, should be emphasized will be called. Particularly suitable cations G are based on the sodium or triphenylmethyl cation and on trialkylammonium cations, such as trimethyl, triethyl or tri-n-butylammonium, or trialkylphosphonium cations such as trimethyl, triethyl or trin-butylphosphonium, and the NN -Dimethylaniliniumion. Preferred compounds (Ha) are, for example, N, N-dimethylanilinium tetrakis (pentafluorophenyDborat or N, N-dimethylanilinium tetrakis [bis (trifluoromethyl) phenyl] borate.

The strong neutral Lewis acids are e.g. Compounds of the general formula

TX ⁵ X ⁶ X ⁷ (Ilb),

in question in the

X ⁵ to X ⁷ independently of one another for hydrogen, linear or branched C 1 -C 1 -alkyl, preferably C 1 -C 6 -alkyl, such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t -Butyl or n-hexyl, mono- or polysubstituted C ~ to Cio-alkyl, preferably Cι ~ to Cβ-alkyl, for example with halogen atoms such as fluorine, chlorine, bromine or iodine, C _ß - to Ciβ-aryl, preferably C ₆ to C o-aryl, for example phenyl, which can also be substituted one or more times, for example with halogen atoms such as fluorine, chlorine, bromine or iodine, for example pentafluorophenyl, alkylaryl with 1 to 10 C atoms, preferably 1 to 6 carbon atoms in the alkyl radical and 6 to 14 carbon atoms, preferably 6 to 10 carbon atoms in the aryl radical, for example benzyl or fluorine, chlorine, bromine or iodine.

Particularly preferred among the radicals X ⁵ to X ⁷ are those which have halogen substituents. Pentafluorophenyl should preferably be mentioned. Particularly preferred are compounds of the general formula (IIb) in which X ⁵ , X ⁶ and X ^{7 are} identical, preferably tris (pentafluorophenyl) borane.

As a strong neutral Lewis acid, alumoxane compounds are further preferred among the cocatalysts. In principle, those compounds which have an Al — C bond are suitable as alumoxane compounds. Open-chain and / or cyclic alumoxane compounds of the general formula (IIc) or (Ild) are particularly suitable as cocatalysts.

R ⁹

in which

R ⁹ independently of one another is a C 1 -C ₄ -alkyl group, preferably a methyl or ethyl group, and k is an integer from 5 to 30, preferably 10 to 25.

These oligomeric alumoxane compounds are usually prepared by reacting a solution of trialkylaluminum with water and include in EP-A 0 284 708 and US-A 4,794,096.

As a rule, the oligomeric alumoxane compounds obtained are mixtures of both linear and cyclic chain molecules of different lengths, so that m is to be regarded as the mean. The alumoxane compounds can also be present in a mixture with other metal alkyls, preferably with aluminum alkyls, such as triisobutyl aluminum or triethyl aluminum. Methylalumoxane (MAO) is preferred, in particular in the form of a solution in Toluene used. The production of .methylalumoxane is described in detail, for example, in EP-A 284 708.

Aryloxyalumoxanes, as described in US Pat. No. 5,391,793, and amidoaluminoxanes, as described in US Pat

US Pat. No. 5,371,260, aminoaluminoxane hydrochlorides, as described in EP-A 0 633 264, siloxyaluminoxanes, as described in EP-A 0 621 279, or alumoxane mixtures.

The alumoxanes described are used either as such or in the form of a solution or suspension, for example in aliphatic or aromatic hydrocarbons, such as toluene or xylene, or mixtures thereof.

Ionic compounds with Bronsted acids as cations and preferably also non-coordinating counterions are mentioned in WO 91/09882, to which reference is expressly made here. Preferred as a cation is e.g. N, N-dimethyl.

Mixtures of the aforementioned cocatalysts can of course also be used.

The preparation of the homo- and copolymers according to the processes according to the invention can be carried out in a non-polar aliphatic or aromatic aprotic solvent, e.g. in heptane, i-butane, toluene or benzene, as well as in a polar aprotic solvent. Suitable polar aprotic solvents are e.g. Halogenated hydrocarbons such as dichloromethane, chloroform, carbon tetrachloride or chlorobenzene, linear or cyclic ethers such as diethyl ether or tetrahydrofuran, furthermore acetone, dimethyl sulfoxide, dimethylformamide, hexamethylphosphoric triamide or acetonitrile. Of course, any, preferably homogeneous, mixtures of the abovementioned solvents can also be used. Dichloromethane, toluene, i-butane, chlorobenzene and acetonitrile and mixtures thereof are particularly preferred.

The amount of solvent is usually determined so that the starting compounds are in dissolved form at the start of the reaction. The transition metal-catalyzed polymerization process can also be carried out in bulk or in the gas phase. The transition metal compounds (III) can also be used in supported form in the polymerization in the gas phase. Both inorganic and organic materials are suitable as carrier materials. Suitable inorganic carrier materials are, for example, silica gel, aluminum, magnesium, titanium, zirconium, Boron, calcium or zinc oxides, aluminosilicates, polysiloxanes, talc, layered silicates, zeolites or metal halides such as MgCl ₂ . Organic carrier materials are based, for example, on prepolymers of olefin (co) polymers, as are obtained, for example, using the processes according to the invention. Suitable support processes are known to the person skilled in the art and can be found, inter alia, for supported Ziegler-Natta catalysts in Makromol. Chem. Phys. 1994, 195, 3347, Macromol. Rapid Commun. 1994, 15, 139-143 and Angew. Chem. Int. Ed. Engl. 1995, 34, 1143-1170) and for supported metal ocene catalysts in EP-A-0 308 177 and in US 4,897,455, US 4,912,075 and US 5,240,894.

The process can be carried out either continuously or batchwise.

The (co) polymerization is usually carried out at temperatures in the range from -40 to 160 ° C., preferably in the range from -20 to 100 ° C. and particularly preferably from 0 to 80 ° C. Depending on the reaction conditions chosen, the reaction times are generally between a few minutes, 1 to 2 hours or several days. Gaseous reaction components such as ethene are pressed onto the reaction mixture.

The (co) polymerization generally takes place at a pressure in the range from 0.1 to 3000 bar, preferably from 0.5 to 100 bar and particularly preferably from 1 to 80 bar.

The concentration of transition metal compound (I) is generally set to values in the range from 10 ^{~ 9} to 0.1, preferably in the range from 10 " ⁸ to 10" ² and particularly preferably in the range from 5 x 10 ^-7 to 5 x 10 ^{- 2} mol / 1 set.

The initial concentration of α-olefin is generally in the range from 10 ^-3 to 10 mol / 1, preferably in the range from 10 ^-2 to 5 mol / 1.

The polymerization can be stopped by adding a deactivating reagent such as triphenylphosphine, by adding a low molecular weight alcohol such as methanol or ethanol or a mixture of a mineral acid such as hydrochloric acid and a low molecular weight alcohol such as methanol.

The (co) polymers obtained by the process according to the invention generally have molecular weight distributions M _w / M _n in the range from 1.1 to 5, preferably from 1.1 to 3.5. With the transition metal compounds according to the invention, highly linear polyethene with very low branching numbers is achieved. The number of branches is typically below one alkyl branch per 1000 carbon atoms.

With the method according to the invention, homo- and copolymers can be obtained from α-olefins. The share of in that

Copolymer incorporated longer chain comonomer e.g. 1-hexene, can be varied in a wide range and easily takes on values greater than 4 mol%. Furthermore, e.g. Copolymers of ethene and higher α-olefins such as 1-butene, 1-pentene or 1-hexene, in particular 1-hexene, are obtained which are e.g. in the case of

Obtained copolymerization with 1-hexene in addition to butyl and methyl branches. With the method according to the invention it is therefore possible to directly control the melting point and the glass transition temperature of the synthesized products in the desired manner, i.e. set to lower values. These comonomers are easy to handle and can be incorporated into other polymer mixtures. They are suitable, for example, as an additive to LD polyethene and contribute to the mixtures obtained being easier to process, less brittle and having better toughness.

The transition metal compounds (I) are characterized by extremely high activities, have little or no loss of activity even with a longer polymerization time, and thus ensure high productivity.

The present invention is explained below using examples.

Examples

The gel permeation chromatography was carried out on a Waters (150 C) device with 1, 2, 4-trichlorobenzene as eluent (flow rate: 1 ml / min) against a polyethylene standard at 140 ° C. in accordance with DIN 55 672.

The ¹ H-NMR and ¹³ C-NMR spectra were recorded on a device from Bruker (ARX 300) with CD ₂ CI ₄ as solvent.

The DSC spectra were recorded on a device from Perkin-Elmer (Series 7) at a heating rate of 20 K / min.

The viscosity was determined in solution according to DIN 53 728 as an η value (dl / g). Methylalumoxane (MAO) was used as a 30% solution in toluene. It is a commercially available product from Witco.

The preparation of the catalyst complexes as well as the polymerization reactions were carried out in the absence of air and moisture and using protective gas techniques known in organometallic chemistry with nitrogen as the protective gas.

As comparative transition metal compounds VI and V2, 2,6-bis [1- (2,6-dimethylphenylimino) ethyl] pyridine and 2,6-bis [1- (2,6-diisopropylphenylimino) ethyl] pyridine-iron (II) were chloride used. These compounds were synthesized according to a regulation according to WO 99/12981.

A. Preparation of the catalyst complexes

1.) 2,6-bis- [1- (2,6-dibromo-4-methylphenylimine) ethyl] yridine (pybr4):

2,6-Diacetylpyridine (1.63 g), 2,6-dibromo-4-methylaniline (5.3 g) and p-toluenesulfonic acid (170 mg) were refluxed using a water separator in benzene (50 ml) for 2 d heated. The cooled reaction mixture was diluted with diethyl ether (100 ml) and washed with aqueous sodium hydrogen carbonate solution (100 ml) and water (100 ml). The organic phase was dried over sodium sulfate and concentrated in vacuo. The residue obtained was washed with hot methanol (80 ml) and crystallized from 1-butanol. Filtering, washing with pentane and drying in vacuo provided a yellow-brown solid (2.94 g).

2nd ) Fe (pybr4) Cl ₂ (catalyst A2):

2, 6-bis [1- (2, 6-dibromo-4-methylphenylimin) ethyl] pyridine (540 mg) and FeCl ₂ -4 H ₂ 0 (164 mg) were added for 30 min. stirred in 1-butanol (30 ml) at 75 ° C. The volatile components were removed in vacuo and the residue extracted three times with dichloromethane (25 ml). After removal of the solvent in vacuo, washing of the residue with ether and pentane and removal of the last solvent residues in a high vacuum, a blue powder (550 mg) was obtained.

3.) 2,6-bis- [1- (2,6-dichlorophenylimino) ethyl] pyridine (pycl4): 2,6-diacetylpyridine (4.1 g), 2,6-dichloroaniline (8.1 g) and p-Toluenesulfonic acid (500 mg) was heated under reflux in toluene (150 ml) using a water separator for 24 h. The cooled reaction mixture was hydrolyzed with sodium bicarbonate, the organic phase separated, twice with water washed, dried over sodium sulfate, filtered and evaporated to dryness. The crude product was crystallized twice from 1-butanol (40 ml each), the precipitate was filtered, washed with pentane and concentrated in vacuo. Chromatography on silica gel gave pure product.

4.) Fe (pycl4) Cl ₂ • THF (catalyst A4):

2,6-bis- [1- (2,6-dichlorophenylimino) ethyl] pyridine (477 mg) and FeCl ₂ • 4 H ₂ 0 (200 mg) were stirred in tetrahydrofuran (20 ml) for 20 h at room temperature. After addition of diethyl ether (10 ml) and stirring for 30 min, the blue solid was separated off by filtration and the last solvent residues were removed in vacuo (yield: 480 mg).

B. Polymerization reactions

1.) Polymerization in the stirring flask:

Toluene (250 ml) and a 30% solution of methylalumoxane (MAO) in toluene (10 mmol) were placed in a reaction flask with a mechanical stirrer and an ether line. In the homopolymerizations, ethene was used as the α-olefin; in the copolymerizations, ethene and 1-hexene (25 ml) were used as comonomer. The catalyst complex (100 μmol) obtained according to A. 4.) was added to the reaction mixture and ethene was passed through the polymerization mixture at a temperature of 30 ° C. and at a flow rate of 40 l / h while stirring. After 1 h the reaction was stopped by adding a mixture of conc. Hydrochloric acid (15 ml) and methanol (50 ml) stopped. If the polymer product was already in the form of a precipitate, it was washed with methanol, filtered and the last solvent residues removed in vacuo. If no precipitate had yet separated, the aqueous phase was separated off and extracted with toluene. The combined organic phases were freed from the solvent in vacuo.

Under the conditions according to B1), corresponding comparative (co) polymerizations were carried out using VI or V2 as the catalyst complex instead of Fe [pycl4] C1 ₂ -THF.

Table 1 below explains the reaction parameters of the polymerizations carried out in accordance with B.l.) and the properties of the products obtained.

2.) Polymerization in an autoclave: Depending on the amount of solvent, the polymerization was carried out in a 10 ml, 500 ml or 1 l autoclave. A 30% solution of MAO in toluene was saturated with ethene (1 bar) and thermostated. The catalyst complex, dissolved in toluene, was added to the reaction mixture and the desired reaction pressure was set immediately with ethene. The polymerization was stopped by releasing the ethene pressure, the reaction mixture was poured into methanol / HCl (10: 3) and collected by filtration. Washing with methanol and drying under high vacuum provided the polymeric product.

Under the polymerization conditions according to B.2.), Iron complexes containing 2, 6-bis- [1- (2, 6-dimethyl-phenyl-imine) ethyl] pyridine or 2,6-bis- [1- (2, 6-diisopropyl-phenylimine) ethyl] pyridine were chelated (VI and V2), corresponding comparative polymerizations were carried out.

Tables 2 and 3 below explain the reaction parameters of the polymerizations carried out in accordance with B. 2.) and the properties of the products obtained.

Table 1: (Co) polymerizations at an ethene pressure of 1 bar according to B. 1.)

a) determined by DSC; b) determined according to DIN 53728; c) determined by means of gel permeation chromatography; d) determined by means of IR spectroscopy; e) determined by means of ¹³ C-NMR spectroscopy; f) no comonomer incorporation was observed.

Table 2: Polymerization in an autoclave according to B. 2.)

Table 3: Polymer properties of the tests carried out according to B. 2.) (see also Table 2)

a) determined by means of gel permeation chromatography;

b) Comparative experiment.

Claims

claims

1. A process for the preparation of homo- or copolymers of α-olefins, characterized in that the starting monomer or monomers in the presence of one or more transition metal compounds (I) of the general formula (I)

in which the substituents and indices have the following meaning:

R ¹ , R ² C ₆ - to Ci ₆ ~ aryl with halogen, nitro, cyano, sulfonato or trihalomethyl substituents in the two ortho positions to the point of connection between aryl and N ^a or N ^b ,

R ³ , R ^{4 are} hydrogen, C 1 to C ₀ alkyl, C ₃ to Cio-cycloalkyl, C ₆ to C ₆ aryl, alkylaryl having 1 to 10 C atoms in the alkyl and 6 to 14 C atoms in the aryl part or Si (R ⁸ ) ₃ with

R ⁸ Ci to Cio alkyl, C ₃ to C ₀ cycloalkyl, C ₆ to C ₆ ~ aryl, alkylaryl with 1 to 10 C atoms in the alkyl and 6 to 14 C atoms in the aryl part,

R ⁵ , R ⁶ , R ^{7 are} hydrogen, C ₁ -C 8 -alkyl, C ₃ - to Cio-cycloalkyl, C ₆ - to C ₆ -aryl, alkylaryl having 1 to 10 C atoms in the alkyl and 6 to 14 C atoms in the aryl part or Si (R ⁸ ) ₃ or functional groups based on the elements of groups IVA to VIIA of the periodic table of the elements or R ⁵ and R ⁶ and / or R ^δ and R ⁷ together form an annellated five- , six- or seven-membered aliphatic or aromatic, substituted or unsubstituted

Carbo- or heterocycle, M Fe, Ru, Co or Rh,

T, Q neutral or monoanionic monodentate ligands,

A a non or poorly coordinating anion,

m, p 0, 1, 2 or 3,

q 1, 2 or 3 and

n 1, 2 or 3

and a strong neutral Lewis acid, an ionic compound with a Lewis acidic cation or an ionic compound with a Bronsted acid as a cation as a cocatalyst.

2. The method according to claim 1, characterized in that linear and branched hydrocarbons having two to 26 carbon atoms are used as α-olefins.

3. Process according to claims 1 or 2, characterized in that at least two different α-olefins selected from α-olefinically unsaturated linear or branched hydrocarbons having two to 26 carbon atoms are used as starting monomers.

4. Process according to claims 1 to 3, characterized in that M iron (Fe) and R ¹ and R ² independently of one another

2,6-dibromo-, 2, 6-dichloro-, 2, 6-dibromo-4-methyl- or 2,6-dichloro-4-methylphenyl or 2,5-dibromo-, 2,5-dichloro-, 2nd , 5-dibromo-4-methyl- or 2,

5-dichloro-4-methylpyrrolid mean.

Transition metal compound of the general formula

in which the substituents and indices have the following meaning:

R ¹ , R ² or C ₆ ~ to Ci ₆ ~ aryl with halogen, nitro, cyano,

Sulfonato or trihalomethyl substituents in the two ortho positions to the point of attachment between aryl and N ^a or N ^b ,

R ³ , R ⁴ hydrogen, Cι ~ to Cio-alkyl, C ₃ - to Cio-cycloalkyl, C ₆ - to Ci ₆ -aryl, alkylaryl with 1 to 10 carbon atoms in the alkyl and 6 to 14 carbon atoms in Aryl part or Si (R ⁸ ) ₃ with

R ^{8 is} Ci- to Cio-alkyl, C ₃ - to -CC ₀ cycloalkyl, C ₆ - to -CC ₆ aryl, alkylaryl with 1 to 10 C atoms in the alkyl and 6 to 14 C atoms in the aryl part,

R ⁵ , R ⁶ , R ^{7 are} hydrogen, C 1 to C 10 alkyl, C ₃ to C ₀ cycloalkyl, C to C ₆ aryl, alkylaryl having 1 to 10 C

Atoms in the alkyl and 6 to 14 carbon atoms in the aryl part or Si (R ⁸ ) ₃ or functional groups based on the elements of groups IVA to VIIA of the periodic table of the elements or R ⁵ and R ⁶ and / or R ⁶ and R ⁷ each together form an annellated five-, six- or seven-membered aliphatic or aromatic, substituted or unsubstituted carbo- or heterocycle,

M Fe, Ru, Co or Rh,

T, Q neutral or monoanionic monodentate ligands,

a non or poorly coordinating anion,

m, p 0, 1, 2 or 3, q 1, 2 or 3 and

n 1, 2 or 3.

6. transition metal compound according to claim 5, characterized in that R ¹ and R ² independently of one another 2,6-dibromo-, 2, 6-dichloro-, 2, 6-dibromo-4-methyl- or 2, 6-dichloro-4th -methyl-phenyl or 2,5-dibromo-, 2, 5-dichloro-, 2, 5-dibromo-4-methyl- or 2, 5-dichloro-4-methylpyrrolid and that M cobalt (Co) or iron (Fe ) mean.

7. Catalyst system for the (co) polymerization of α-olefins, containing as essential components a transition metal compound according to claims 5 or 6 and as cocatalyst a strong neutral Lewis acid, an ionic compound with a Lewis acid cation or an ionic compound with a Bronsted acid as a cation.

8. Use of the transition metal compound according to claims 5 or 6 or the catalyst system according to claim 7 for the (co) polymerization of α-olefins.

9. copolymers of α-olefins, obtainable according to claims 3 or 4.

10. Copolymers according to claim 9, characterized in that these copolymers have a polydispersity (M _w / M _n ) less than 3.