MXPA98000021A - Metalocene with bridges replaced with cirilo and its use for polymerization of olef - Google Patents

Abstract

The present invention relates to metallocenes of the formula I, wherein M is a metal group of the group of Ti, Zr, Hf, V, Nb and Ta, or an element of the group of the lanthanides; X1 and X2 represent an alkyl group , alkoxy, aryl, aryloxy, alkenyl, arylalkyl, alkylaryl or arylalkenyl, hydrogen or halogen; L1 and L2, represent a hydrocarbon, which can form a structure walled with M; R represents C, Si, Ge or Sn; and A and B represent a trimethylsilyl radical, B optionally for an alkyl or aryl radical

Description

METALOCENE WITH BRIDGES SUBSTITUTED WITH SILYLIDE AND ITS USE FOR POLYMERIZATION OF OLEFIN D IS CR1PCJ O N L DE L A J N VEN. C I O N The invention relates to novel metallocenes and their use as catalysts in the polymerization of olefins. The metallocenes of the metals of the transition group IV of the Periodic Table of the Elements are highly active catalysts for the polymerization of olefins. The resulting polyolefins have new combinations of properties and supplement the product scale of the polyolefins prepared therefrom using conventional known Ziegler-Natta catalysts. It is known that catalysts based on substituted and unsubstituted bisciclopentadienyl metallocenes without bridging, in combination with aluminoxanes as a co-catalyst, can be used for the preparation of the polyethylene and ethylenelefin copolymers (EXXON EPA 128046). It is also known that stereoregular polyolefins can be prepared using chiral, bridged metallocenes. For bridging the ligand systems, use is made of dimethylsilandiyl groups (CHISSO EPA 316 155), methylphenylalkyl groups (HOECHST EPA 320 762), ethylene groups (Brintzinger et al., J. Organomet. Chem., 288 (1985 ) 63-67), and isopropylidene bridges (Mitsui Toatsu EPA 459 264). Depending on the type of ligand and the substituents, it is possible to prepare isotactic, syndiotactic, hemi-isotactic, stereoblock and atactic homopolymers and copolymers having aliphatic or cyclic structures. As ligands, preference is given to the use of substituted and unsubstituted cyclopentadienyl units (CHISSO EPA 316 155), substituted and unsubstituted indenyl units (Hoechst EPA 302 424, Hoechst EPA 485 823) and also substituted and unsubstituted cyclopentadienyl units. substituted in combination with unsubstituted fluorenyl groups (Mitsui Toatsu EPA 412416). It is also known that bridge metallocenes can be used having a cyclopentadnenyl system and a heterogeneous atom ligand (restricted geometry catalyst) for the polymerization of olefins (EXXON US 5 096867). Among these various types of metallocenes, substituted chiral, bridged bisindenyl systems have attained particular importance. In this way, they were able to show that the type of substituents and the position of the substituents on the metallocene ligand have a significant influence on the reactivity of the catalyst system and the stereoregular structure of the obtained polyolefins. Two possible substitution patterns in particular, have been found to be advantageous. The first possibility results in the substitution of indenyl ligand at position 2, 4 and / or 6 (Hoechst EPA 485823; Angew, Chem., 10 (1992) 1373), while the second possibility is a fusion on the benzene ring of the benzene ring. indenyl ligand (Organometallics 1994, 13, 964-970). Both types of catalyst can be used to prepare isotactic propylene and ethylene-α-olefin copolymers. A multitude of substituted indenyl ligands can be prepared only at a considerable expense. Relatively simple systems having good activity and containing indenyl, 2-methylindenyl or 2-methylbenz [e] indenyl ligands give products, in particular polypropylene, which have relatively low molecular weight masses, which are too low for many applications and they represent the lower limit of industrial use. Therefore, it is an object of the present invention to find additional structural variants of bridged metallocenes as catalysts for the polymerization of olefins, which give polyolefins, in particular polypropylene, having relatively high molar masses.

It has now been surprisingly found that metallocene systems with diol bridges, substituted with lily, are suitable catalysts for the preparation of polyolefins and in particular of polypropylenes having relatively high molar masses. The present invention therefore provides metallocenes of the formula I.

(I) wherein M is a metal selected from the group consisting of Ti, Zr, Hf, V, Nb and Ta, or an element selected from the group consisting of the lanthanides, X- | and X2 are the same or different and each is an alkyl group C-j -C- | or »an alkoxy group C- | -C- | or, an aryl group Cg-Ci or »an aryloxy group Ce-C? or, a C2-C-J alkenyl group 0. a C7-C20 alkyl ary group. an alkylaryl group C7-C20 - a C8-C20 arylalkenyl group »hydrogen or a halogen atom. and L2, a) are the same or different and each is an unsubstituted, monosubstituted or polysubstituted monocyclic or polycyclic hydrocarbon radical containing at least one cyclopentadienyl unit, which can form a sandwich structure with M, or b) Li is a unsubstituted, mono-substituted or polysubstituted monocyclic or polycyclic hydrocarbon radical containing at least one cyclopentadienyl unit, which can form a sandwich structure with M, and L2 is an amido, phosphido or arsenide radical of the formula.

E D where D is nitrogen, phosphorus or arsenic and E is as defined for X- | and X2, R is carbon, silicon, germanium or tin, A and B are the same or different and each are a trimethylsilyl radical of the formula -Si (CH3) 3, wherein B may also be an alkyl radical CJ-CIQ » preferably a C 1 -C 4 alkyl radical, or an aryl radical Cg-C-jo- The preferred ligands Lj and / or L 2 are substituted or unsubstituted cyclopentadienyl, indenyl or fluorenyl radicals. Particular preference is given to cyclopentadienyl, tetramethylcyclopentadienyl, indenyl, 2-methylindenyl, 2-methyl-4-phenyl indenyl, 2-methyl-4,5-benzindenyl and fluorenyl units and also units substituted with ferrocene and ruthenocene as described, for example in EP-A-673946. According to the invention, the following metallocenes are particularly preferred: bis (trimethylsilyl) silandyldicyclopentadienyl zirconium dichloride, bis (trimethylsilyl) silandiyldiindenyl zirconium dichloride, bis (tri methylsi MI) silandiylbis (2-methylindenyl) zirconium dichloride, bi-dichloride ( tri meti t if I i I) silandiylbis (2-methyl-4,5-benzindenyl) zirconium, bis (trimethylsilyl) silandiylbis (2-methyl-4-phenylindenyl) zirconium dichloride, bis (trimethylsilyl) silandiylbis (2-) dichloride methyl-4-naphthindenyl) zirconium, bis (tri-methyllifluoride) dichloride, silyldifluorenyl-zirconium dichloride, bis (trimethylsilyl) silandyl (fluorenyl) (cyclopentadienyl) zirconium dichloride, bis (trimethylsilyl) silandyl (fluorenyl) dichloride (indenyl) ) zirconium and bis (trimethylsilyl) silandiil dichloride (tetra methylo cyclopentadienyl) (indenyl) zirconium, Methyl (trimethylsilyl silandyl-dicyclopentadienylzirconium dichloride, Methyl (trimethylsilyl) silandyl-diindenylzirconium dichloride, Methyl (trimethylsilyl) silanylisobis (2-methylindenyl) zirconium dichloride, Methyl (trimethylsilyl) dichloride silandiylbis (2-methyl-4,5-benzindenyl) zirconium, Methyl (trimethylsilyl) silandylbis (2-methyl-4-phenylindenyl) zirconium dichloride, Methyl (trimethylsilyl) silandylbis (2-methyl-4-naphthindenyl) zirconium dichloride, Methyl (trimethylsilyl) silandiildifluorenylzirconium dichloride, Methyl (trimethylsilyl) silandyl dichloride (fluorenyl) (cyclopentadienyl) zirconium, methyl (trimethylsilyl) silandyl (fluorenyl) (indenyl) zirconium dichloride and methyl (trimethylsilyl) silandyl (tetramethylcyclopentadienyl) (indenyl) zirconium dichloride. The invention further provides a method for preparing metallocenes I, which comprises reacting a compound of formula II wherein L- |, L2, A, B and R are as defined for formula I and M 'is an alkali metal, preferably lithium, with a compound of formula III M (X ') 2 * 1X2 (MI), where M, X- | and X2 is as defined for formula I and X 'is a halogen atom, preferably chlorine. The metallocenes I can be prepared, for example, according to the following reaction scheme: X-R-? ? H 1 I i Butyl Li - * - H- LiLi B »H- L, -R ~ X H ^ .L2 + Butyl Ll - H- 2 Li A M 1 H-L, -R- H- L2 Li H - Li- R- L, -H I B B TO I H - L - | - R-L2 - H * 2ButylLi «- Li L? -R-L2- B B L - X = F; Cl; Br; J X = F; Cl; Br; I X-j, X2, Li and L2 are as defined above. In addition, amido, phosphide and arsenide radicals can be used as L2 ligands, wherein the substituents of these ligands are as defined for X- | and X2 or while others are fused or substituted with ferrocenyl or ruthenocenyl. The reaction of the dimethallylated compound of the formula II with the metal halide of the formula III in the last step of the process of the invention can be carried out, for example, as described in EPA 659756. However, the reaction of the dimethalated compound of the formula II with the metal halide of the formula III in the last step of the process of the invention is advantageously carried out in solvent mixtures of aromatic and / or aliphatic hydrocarbons, which can also be halogenated, with dialkyl ethers, preferably mixtures of alkane / ether, such as, for example, mixtures of hexane / ether. The solvent mixtures preferably have transition energies Ey (30) (empirical parameter as a measure of the polarity of the solvents) in the range from 35.5 to 31.5 kcal / moles, particularly preferably from 34.5 to 32.5 kcal / moles. According to Chemical Reviews 1994, Vol. 94, No. 8, 2319 ff., The transition energy Ej (30) is defined as the dependence of the band position and intensity of the betaine of pyridinium N-phenoxide of chromophore in the selected solvent. When such charge transfer complexes dissolve, the maximum absorption of longer wavelength suffers a shift that increases with the polarity of the solvent. The transition energy Ej (30) in kcal / moles is calculated from the measured frequency v of this maximum. Suitable hydrocarbons and dialkyl ethers are, in particular, those listed, for example, in II Chemical Reviews 1994, Vol. 94, No. 8, pp. 2337-2340. Examples of suitable aromatic hydrocarbons are compounds such as toluene, benzene or p-xylene. The aliphatic hydrocarbons can be, for example, all C5-C-J2 alkanes. Preference is given to n-pentane, n-hexane, n-heptane or cyclohexane. n-Hexane is of particular utility. Among the dialkyl ethers, preference is given to all C2-C4 dialkylethers, for example diethyl ether, di-n-propyl ether, diisopropyl ether, and di-n-butyl ether or tert-butyl methyl ether. Examples of suitable halogenated hydrocarbons are all C1-C4 chloroalkanes. Particular preference is given to dichloromethane. The invention further provides the use of the metallocenes of the invention as polymerization catalysts in the polymerization of olefins, and also provides an olefin polymerization process wherein the metallocenes of the invention are used as catalysts. In the olefin polymerization, preference is given to the use of a cocatalyst, for example, an aluminoxane of the formula IV for the linear type: (IV) and / or formula V for the cyclic type, wherein in formulas IV and V, the radicals may be the same or different and each is a C- | -Cß alkyl group and n is an integer of 1-50. Preferably, the radicals are identical and are methyl, isobutyl, phenyl or benzyl; Particular preference is given to methyl. Aluminoxane can be prepared in various ways by known methods. One possibility is, for example, to react aluminum alkyls with aluminum sulphate containing water of crystallization (Hoeschst EP 302424). In the present invention, commercial MAO (methylaluminoxane, from Witco, Germany) is used. It is also possible to mix the metallocene of the formula I with an aluminoxane of the formula IV and / or V before being used in the polymerization reaction. The mixture is preferably made in solution. Preference is given to dissolving the metallocene in an inert hydrocarbon and subsequently mixing it with the aluminoxane solution. Suitable inert hydrocarbons are aliphatic or aromatic hydrocarbons. Preference is given to the use of toluene. The concentration of aluminoxane in the solution is p on the scale of 5-30% by mass, based on the total solution. The metallocene is preferably used in an amount of 10 mol-1 mol per mol of aluminoxane The mixing time is from about 5 minutes to 24 hours, preferably from 5 to 60 minutes The mixing is generally carried out at a temperature of - 10 to + 70 ° C, in particular from 10 to 40 ° C. The matalocene can also be applied to a support The suitable supports are, for example, the inorganic oxides of the metals of the main groups II-IV of the Table Periodic preference is given to the oxides of the metals magnesium, calcium, aluminum, silicon, boron and their mixtures, for example the commercially available aluminum oxides "Alumina Typ C" (Degussa) and silicon oxides of the type "Silica Davison Grade 952-957"or of the type" Aerosil "(Degussa) and also mixtures AI2O3 and Si? 2- Particular preference is given to catalyst supports as described in EP-A 685494. Polymerization can be carried out in solution process , suspension or phase of gas, continuously or intermittently at a temperature of -10 to + 200 ° C, preferably of +20 to + 80 ° C. The olefins of the formula Ra-CH = CH-RD are polymerized or copolymerized. In this formula, Ra and RD are the same or different and each is a hydrogen atom or an alkyl radical having from 1 to 20 carbon atoms. However, Ra and Rb together with the carbon atoms connected to them can also form a ring. For example, olefins such as ethylene, propylene, 1-butene, -hexene, 4-methyl-1-pentene, 1-octene, cyclopentene, norbornene or norbornadiene are polymerized or polymerized. In particular, ethylene, propylene and 1-butene are polymerized or copolymerized. If necessary, hydrogen is added as a molar mass regulator. The total pressure in the polymerization is 0.5-150 bar. Preference is given to carrying out the polymerization at a pressure scale of 1-40 bar. It has been found to be advantageous to carry out the reaction of the monomers of the presence of the metallocene catalyst system at an aluminum molar ratio of the oligomeric aluminoxane compound to the transition metal of the matalocene compound of 10 ^: 1 to 10 ^: 1, preferably from 10 ^: 1 to 1? 2; l. If the polymerization is carried out as a suspension or solution polymerization, use is made of an inert solvent. It is possible to use, for example, aliphatic or cycloaliphatic hydrocarbons such as pentene, hexane or cyclohexane. You can also use toluene. Preference is given to carrying out the polymerization in the liquid monomer.

According to the invention, the copolymerization of ethylene with propylene is carried out in a liquid propylene or in hexane as suspending medium. In the polymerization in liquid propylene, ethylene is preferably introduced in such an amount that a partial pressure ratio Pc2 ^ '3c3 greater than 0.5, in particular greater than 1.0, is established above the liquid phase (Pc2 = partial pressure of ethylene in the gas phase above the suspension, Pc3 = partial pressure of propylene in the gas phase above the suspension). In copolymerization in hexane as the suspending medium, an ethylene / propylene mixture having a propylene content of 1 to 50 mol%, preferably 5 to 30 mol%, is fed. The total pressure is kept constant during the polymerization by dosing additional quantities. The total pressure is from 0.5 to 40 bar, preferably from 1 to 20 bar. The polymerization time is generally from about 10 minutes to 6 hours, preferably from 30 minutes to 2 hours. The catalysts used according to the invention expand the scale of active metallocenes to the polymerization to prepare homopolymers and copolymers of polyolefins. In particular, the metallocenes of the invention produce polymers and copolymers having a molar mass. high, industrially relevant and a narrow molar mass distribution on the industrially important temperature scale from 20 to 80 ° C. A further advantage arises from the preferred metallocene preparation process of the invention, which allows high yields of the pure racemate or pseudoracemate form of the resulting metallocene compound which will be obtained stereoselectively in the reaction of the dimethalated ligand pairs of the formula II with the metal halide of the formula III using the preferred solvent mixtures, in particular ether / alkane mixtures. For the purposes of the present invention pseudoracemates are compounds that have the same three-dimensional arrangement of the ligands as racemates, but are asymmetric due to the way in which the bridge is substituted. The following examples illustrate the invention. In the examples: Mw = weight-average molar mass in g / mol, Mn = number-average molar mass in g / mol, Mw / Mn = molar mass distribution, determined through gel penetration chromatography, MS = spectrometry mass 1H-MNR = "? spectroscopy of) Nuclear magnetic resonance imaging) structure of 1 ^ C-MNR = 13Q spectroscopy of) nuclear magnetic resonance catalyst) EXAMPLE I: Bis (trimethylsilyl) silandiildi-cyclopentadienylzirconium dichloride 5g (16.4 mmoles) of bis (trimethylsilyl) dicyclopentadienylsilane (K. Hassler, K. Schenzel, J. Organomet, Che. 484, C1-C4 (1994)) were dissolved in 20 ml of diethyl ether. The solution is cooled to -78 ° C and mixed with 21 ml of a 1.55 molar solution of n-buty-lithium in n-pentane. The solution is warmed to room temperature, the bis (trimethylsilyl) silandiyldicyclopentadienyldilithium was filtered and dried under reduced pressure. The yield is 3.7 g (71.4% theory). 1.1 g (3.5 mmol) of bis (trimethylsilyl) silandyldicyclopentadienyldilithium in 50 ml of toluene was suspended. The suspension was cooled to -40 ° C and mixed with 1.3 g (3.5 mmoles) of bis (tetrahydrofuran) zirconium tetrachloride. After warming to room temperature, the solution was stirred for 24 hours at room temperature and then filtered. The solvent was removed under reduced pressure, the residue was extracted with n-pentane and the extract was evaporated to dryness, leaving bis (trimethylsilyl) silandiylcyclopentadienylzirconium dichloride). The yield is 600 mg. (37.2% theory).

MS (El, _70__ey, _200? CJi m / e = 464 (100%), molecular peak; 354 (95%), cation of 1-methylsilyl-3-silyl-2-silandyl-2-dicyclopentadienylzirconium chloride radical; 318 (49%), radical cation of 1-methylsilyl-3-silyl-2-silandyl-d-cyclope ntad i eni I zirconium. N-MNR CgDe): 0.14 ppm (18 H, d); 5.87 ppm (4 H, t); 6.75 ppm (4 H, t) HC-MNR .. THF.-_ D8ll 0.19 ppm; 103.97 ppm; 118.30 ppm; 125.90 ppm; 128.35 ppm.

EXAMPLE II: Bis (trimethylsilyl) silyueldifronitrile dichloride (mixture of diastereomer).

Initially 5 g (20.4 mmoles) of 2,2-dichlorohexamethyltrisilane (G. Kolliger, Thesis 1993, Technical University of Graz) were charged in 50 ml of n-pentane. The solution was cooled to -78 ° C and mixed with 5 g (40.8 mmol) of indenyl lithium. After warming to room temperature, the solution was stirred for 24 hours, subsequently it was filtered, again cooled to -78 ° C and 21 ml of a 1.58 molar solution of n-butyllithium were added dropwise in n. -pentano. After warming to room temperature, the reaction mixture was filtered and the b.sub.s (tr.methylsilyl) silandiidiindenylldjthio obtained as filter cake was dried under reduced pressure. The yield is 3.5 g (40.9% theory). A solution of 3.5 g (8.4 mmol) of bis (trimethylsilyl) silandiyldiindenyldilithium in 50 ml of toluene was cooled to -30 ° C. 3.1 g (8.3 mmol) of bis (tetrahydrofuran) zirconium tetrachloride was added to the suspension. After warming to room temperature, the reaction mixture was heated at 50 ° C for 5 hours in a water bath and subsequently filtered. The solvent was removed under reduced pressure, the residue was taken up in n-pentane and the solution was filtered. Removal of the solvent under reduced pressure leaves the bis (trimethylsilyl) silandiyldiindenylzirconium dichloride. The yield is 1.2 g (25.5% theory).

MS (EI, 70. ey, _2_00_ßC) L m / e = 564 (100%), molecular peak; 453 (29%), cation of 1-trimethylsilyl-2-silandyl-2-diindenylzirconium chloride radical; 389 (36%), cation of radical 1-methylsilyl-2-silandyl-2-diindenyl zirconium; 289 (58%), cation of 1-methylsilyl-2-silandyl-2-diindenyl radical. H-MNR ITHF-dß)! -0.0917 ppm (18 H, t); 565 ppm (2 H, d); 6.73 ppm (2 H, d); 7.13 ppm (8 H, m) EXAMPLE III Bis (trimethylsilyl) silandylbis (2-methylindenyl) zirconium dichloride.

A solution of 3 g (20 mmol) of 2-methylidene (CF Koelsch, PR Johnsen, J. Am. Chem. Soc. 65, 567, (1943)) in 50 ml of diethyl ether was cooled to -78 ° C. and mixed with 14.6 ml of a 1.58 molar solution of n-butyllithium in n-pentane. The solution was warmed to room temperature and the formed 2-methylindenyl-lithium was filtered and dried under reduced pressure. The yield is 2.5 g (91.9% theory).

A solution of 2.5 g (18.4 mmol) of 2-methylindenyl-lithium in 50 ml of diethyl ether was added at -78 ° C to 2.2 g (9.2 mmol) of 2., 2-dichlorohexamethyltrisilane in 50 ml of n-pentane. After warming to room temperature, the reaction mixture was heated at 50 ° C for 4 hours in a water bath, subsequently filtered by heating, cooled again to -78 ° C and mixed with 11.6 ml of a solution 1.58 molar of n-butyl lithium in n-pentane. After warming to room temperature, the solution was filtered and the bjs (trimethylsilyl) silandiylbis (2-methylindenyl) di I ti or obtained as filter cake was dried under reduced pressure. The yield is 2.6 g (63.4% theory). 1.8 g (4.9 mmol) of bis (tetrahydrofuran) zirconium tetrachloride was added at -30 ° to 2.2 g (4.9 mmol) of bis (trimethylsilyl) silandylbis (2-methylindenyl) dilithium in 50 ml of toluene. After warming to room temperature, the reaction mixture was heated at 50 ° for 4 hours in a water bath, subsequently filtered and the toluene was removed under reduced pressure. The residue was washed with n-pentane. After decanting the n-pentane, the bis (trimethylsilyl) silandylbis (2-methylindenyl) zirconium dichloride was dried under reduced pressure. The yield is 800 mg (27.6% theory). MS (El. 70 eV. 200 ° C: m / e 596 (0.5%), molecular peak; 483 (4.7%), cation of 1-trimethylsilyl-3-silyl-2-silandyl-2-bis- (2-methylindenyl) zirconium radical cation; 441 (10.6%), of cation of radical 1-methylsilyl-3-silyl-2-silandyl-2-bis (2-methylindenyl) zirconium; 383 (62.4%), cation of 1-trimethylsilyl-3-silyl-2-silandyl-2-bis (2-methylindenyl) radical; 348 (26%), cation of 1-dimethylsilyl-2-bis (2-methylindenyl) silyl radical; 129 (100%), cation of radical bis (2-methylindenyl); 115 (61.3%), cation of 2-methylindenyl radical. H-MNR _i HF d8) _L -0.0621 ppm (18 H, t); 2.26 ppm (6 H, s); 5,878 ppm (2 H, s); 6.4069 ppm (2 H, d); 7.1-7.2 ppm (8 H, m).

EXAMPLE IV: Methyl (trimethylsilyl) silandiylbis (2-methylindenyl) zirconium dichloride .6 ml of a 1 molar solution of methyl lithium (25.6 mmol) under argon at -80 ° C was added to a solution of 4.35 g (11.6 mmol) of 1,1,1,2-tetramethylbis (2-methyl). twenty-one tilindenyl) disilane (M. Kumada, T. Kondo, K. Mimura, M. Ishikawa, K. Yamamoto, S. Ikeda, M. Kondo, J. Organomet, Chem. 43 (1982) 293), in 50 ml of diethyl ether absolute. The reaction mixture was brought to room temperature over a period of 5 hours and further stirred for 13 hours at room temperature. After extracting the solvent in a high vacuum, a white residue was obtained. This was mixed with 100 ml of absolute n-hexane, the resulting suspension was filtered under argon and the residue of the filtration was washed 5 times in absolute n-hexane. After drying for 2 hours in a high vacuum, 4.43 g of the corresponding dilithium salt (yield 98.7%) were obtained as a white pyrophoric powder, which was used without further purification for the synthesis of zirconocene dichloride. A suspension of 2.68 g of zirconium tetrachloride (11.5 mmole) in 50 ml of absolute n-hexane was added at -85 ° C to a solution of 4.43 g of the dilithium salt (11.5 mmole) in 50 ml of absolute diethyl ether. After warming to room temperature, the mixture was stirred for 52 hours at room temperature. After extracting the solvent in a high vacuum, the solid residue was washed once with absolute n-hexane and twice with a little absolute diethyl ether, 50 ml of absolute methylene dichloride was collected, filtered under argon and the filtrate was filtered. evaporated in a high vacuum until the formation of the precipitate began. After 2 days at -20 ° C, the formed precipitate was filtered, washed a number of times with a little absolute n-hexane and dried in a high vacuum. This gives 5.18 g of methyl (trimethylsilyl) silandylbis (2-methylindenyl) zirconium dichloride (84.4% yield, rae: meso = 20) as a yellow, microcrystalline powder. c24H28Si2ZrC, 2 (534 79 g / rnol) MS (EI 30 eV (m / e (%)): M +: 534 (100), M + -Me: 519 (8), M + -CI: 499 (8), M + -CI-Me: 484 ( 12), M + SiM3: 461 (100), M + SiMe3-CI-2H: 424 (31), M + SiMe3-CI-Me-2H: 409 (18); 1H-MNR (CD2Cl2 (ppm): 0.57 (9H, s, Si (CH3) 3), 1.44 (3H, s, Si (CH3)), 2.20 and 2.27 (6H, each s, (CH3) -nd); 6.65 to 7.82 (10H, m, Ind).

For example, polymerization E j e m p I o 1: After rendering inert, a stirred reactor of 21 was charged at room temperature with 6.6 g of MAO with 10% strength and 300 g of purified, liquid propylene and the mixture was stirred for 15 minutes. mg of bis (trimethylsilyl) silandyldicyclopentadienyl zirconium dichloride were dissolved in 2.4 ml of toluene and mixed with 6.6 g. of MAO with a resistance to 10%. The catalyst solution was subsequently injected into the reactor with an additional 200 g of propylene and the mixture was heated to the polymerization temperature of 70 ° C, which was kept constant for a period of 2 hours. The reaction was stopped after 1 hour by vaporization of propylene. This gave 106.3 g of propylene having a molar mass Mw = 25,000 g / moles and a polydispersity Mw / Mn = 2.9.

Example 2 After becoming inert, a stirred 2 I reactor was charged under nitrogen with 3.9 g of MAO with 10% strength and 1 dm ^ of n-hexane and the mixture was stirred for 15 minutes. After degassing the suspension medium and heating the reactor to the reaction temperature of 70 ° C, the polymerization was started by injecting the catalyst solution together with an ethylene / propylene mixture containing 11.3 mol% propylene.

The catalyst solution was prepared by dissolving 3 mg of dichloride of bi s (tri meti I if I i) if land i i I-dicyclopentadienyl zirconium in 1.4 ml of toluene and mixing with 4.0 g of MAO with 10% strength.

The pressure in the reactor was kept constant at 2 bar throughout the polymerization time by dosing additional quantities of the gas mixture. The agitator speed is 700 revolutions per minute and the polymerization time is 2 hours.

This gave 14.8 g of the ethylene-propylene copolymer having a molar mass Mw = 134,000 g / mol and a polydispersity Mw / Mn = 6.3. The propylene content is 2.7 mol%.

Example 3 The experiment was carried out using a method similar to Example 1. MAO was not included in the initial charge in the reactor. The catalyst solution was prepared by dissolving 5 mg of bis (trimethylsilyl) silandyldiindenylcyiinium dichloride in 3.6 ml of toluene and mixing with 9.2 g of MAO with 30% strength.

This gave 45.7 g of polypropylene having a molar mass Mw = 42,000 g / moles and a polydispersity Mw / Mn = 2.0.

Example 4 After becoming inert, a stirred 2 I reactor was charged under nitrogen with 1 dm3 of purified n-hexane. After degassing the suspension medium and heating the reactor to the reaction temperature of 70 ° C, the polymerization was initiated by injecting the catalyst solution together with ethylene.

The catalyst solution was prepared by dissolving 2 mg of bis (trimethylsilyl) silandiyldiindenylzirconium dichloride in 1.7 ml of toluene and mixing with 3.7 g of MAO with 30% strength.

The pressure in the reactor was kept constant at 2 bar throughout the polymerization time by dosing additional amounts of the monomer. The agitator speed is 700 revolutions per minute and the polymerization time is 1 hour.

This gave 25.4 g of polyethylene having a molar mass Mw = 445,000 g / mol and polydispersity Mw / Mn = 5.8.

Example 5 The experiment was carried out using a method similar to Example 1. MAO was not included in the initial charge in the reactor. The catalyst solution was prepared by dissolving 6 mg of bis (trimethylsilyl) silandylbis (2-methylindenyl) zirconium dichloride in 3.2 ml of toluene and mixing with 10.5 g of MAO with 30% strength. The reaction time is 2 hours.

This gave 48.3 g of polypropylene having a molar mass Mw = 336,000 g / moles and a polydispersity Mw / Mn = 2. 2.

Example 6 The experiment was carried out using a method similar to Example 1. MAO was not included in the initial charge of the reactor. The catalyst solution was prepared by dissolving 5 mg of bis (trimethylsilyl) silandi i bis (2-methylindenyl) zirconium dichloride in 26.2 g of MAO with 30% strength. The reaction time is 2 hours.

This gave 92 g of polypropylene having a molar mass of Mw = 248,000 g / moles and a polydispersity Mw / Mn = 2.0.

Example 7 After becoming inert, a 2 I stirred reactor was charged at room temperature with 500 g of purified, liquid propylene and subsequently heated to 70 ° C. 5 mg of bis (trimethylsilyl) silandylbis (2-methylindenyl) zirconium dichloride were dissolved in 2.8 m of toluene and mixed with 8.7 g of MAO with 30% strength. The catalyst solution was injected into the reactor together with ethylene. An ethylene partial pressure of 1 bar was maintained during the reaction time of 2 hours. The reaction was stopped by vaporizing the monomers. This gave 174.4 g of an ethylene / propylene copolymer having a molar mass Mw = 101,000 g / mol and a polydispersity Mw / Mn = 2.7. The propylene content is 16.6 mol%.

Example 8 The experiment was carried out using a method similar to example 1. The reactor was initially charged with 0.76 g of MAO with a resistance of 30%. The catalyst solution was prepared by dissolving 6.4 mg of methyl (trimethylsilyl) silandylbis (2-methylindenyl) zirconium dichloride in 20 ml of toluene. 0.6 ml was mixed with 0.5 g of MAO with 30% strength and introduced into the reactor. The reaction time is 2 hours.

This gave 62.9 g of polypropylene having a molar mass Mw = 249,000 g / moles and a polydispersity Mw / Mn = 2.6.

Claims (9)

) CLAIMS

1. A metallocene of the formula I (I) wherein M is a metal selected from the group consisting of Ti, Zr, Hf, V, Nb and Ta or an element selected from the group consisting of lanthanides, Xj and X2 are the same or different and each is a CJC-JO alkyl, an alkoxy group CJC ^ Q »an aryl group Cg-C- or a aryloxy group Cg-Cio» a C2-C-10 alkenyl group »a group C7-C20 arylalkyl C7-C20 alkylaryl a C8-C20 arylalkenyl group »hydrogen or a halogen atom, and L2 a) They are the same or different and each is a monocyclic or polycyclic unsubstituted, monosubstituted or polysubstituted hydrocarbon radical containing at least one cyclopentadienyl unit, which forms a structure walled with M, or b) L- | is an unsubstituted, mono-substituted or polysubstituted monocyclic or polycyclic hydrocarbon radical containing at least one cyclopentadienyl unit, which can form a sandwich structure with M, and L2 is an amido, phosphido or arsenide radical of the formula D where D is nitrogen, phosphorus or arsenic and E is as defined for X- | and X2, R is carbon, silicon, germanium or tin, A and B are identical or different and each may be a trimethylsilyl radical of the formula -Si (^ 3) 3, wherein B may also be an alkyl radical, preferably a radicall C 1 -C 4 alkyl or an aryl radical Cg- C ^ o.

2. A metallocene according to claim 1, characterized in that the ligands L-j and / or L2 are substituted or unsubstituted cyclopentadienyl, indenyl or fluorenyl radicals.

3. A process for preparing a metallocene of the formula I according to claim 1 or 2, characterized in that it comprises reacting a compound of the formula II with a compound of formula III M (X ') 2X? X2 ("0 wherein L- |, L2, A, B, R, M, X-j, X2 are as defined in claim 1, M 'is an alkali metal and X' is a halogen atom.

4. The process for preparing a metallocene of the formula I according to claim 3, characterized in that the reaction of the compound II with the compound III is carried out in solvent mixtures of aromatic and / or aliphatic hydrocarbons, which can also be halogenated with dialkyl ethers. ?

5. The process according to claim 4, characterized in that the solvent mixtures have transition energies Ej (30) in the scale of 35. 5 to 31.5 kcal / moles, preferably in the range of 34.5 to 32.5 kcal / moles.

6. The process according to claim 4 or 5, further characterized in that a compound of the formula II as a solution in dialkyl ethers are reacted with a compound of the formula III as a suspension in aromatic and / or aliphatic hydrocarbons, which may also be halogenated, wherein the solvent mixture has a transition energy Ej (30) of 35.5 to 31.5 kcal / moles.

7. The use of metallocenes according to any of claims 1 to 6, as polymerization catalysts in the polymerization of olefins.

8. The process for preparing polyolefins through the polymerization of olefins, characterized in that a metallocene is used as the catalyst according to any of claims 1 to 7.

9. The process for preparing polyolefins according to claim 8, characterized in that aluminoxane is used as cocatalyst in addition to the metallocenes.