WO1997042147A1

WO1997042147A1 - Cyclopentadiene compound substituted by aralkyl groups

Info

Publication number: WO1997042147A1
Application number: PCT/NL1997/000198
Authority: WO
Inventors: Gerardus Johannes Maria Gruter; Johannes Antonius Maria Van Beek
Original assignee: Dsm N.V.
Priority date: 1996-05-03
Filing date: 1997-04-16
Publication date: 1997-11-13
Also published as: NL1003012C2; AU2311097A

Abstract

Disubstituted or polysubstituted cyclopentadiene compound in which as least one substituent is of the form -RDR'n, where R is a bonding group between the cyclopentadiene and the DR'n group, D is a hetero atom chosen from group 15 or 16 of the Periodic System of the Elements, R' is a substituent and n is the number of R' groups bonded to D, and in which at least one of the other substituents is an aralkyl group. Metal complexes in which at least one of these cyclopentadiene compounds is present as a ligand are useful as catalysts for the polymerisation of alpha-olefins.

Description

CYCLOPENTADIENE COMPOUND SUBSTITUTED BY ARALKYL GROUPS

The invention relates to a di- or poly- substituted cyclopentadiene compound. Cyclopentadiene compounds, both substituted and unsubstituted, are used widely as a starting material for preparing ligands in metal complexes having catalytic activity. In the great majority of cases, either unsubstituted cyclopentadiene or cyclopentadiene substituted with one to five methyl groups is used. The metals used in these complexes are transition metals and lanthanides.

In J. of Organomet. Chem., 479 (1994), 1-29 an overview is provided of the influence of the substituents on cyclopentadiene as a ligand in metal complexes. Here it is observed, on the one hand, that the chemical and physical properties of metal complexes can be varied over a wide range by adapting the substituents on the cyclopentadiene ring. On the other hand, it is stated that no predictions can be made concerning the effect to be expected of specific substituents.

Hereinafter, cyclopentadiene will be abbreviated as Cp. The same abbreviation will be used for a cyclopentadienyl group if it is clear, from the context, whether cyclopentadiene itself or its anion is meant.

A drawback of the known substituted Cp compounds is that when used as a ligand, they form a metal complex which, when applied as catalyst component in the polymerization of olefins, a considerable amount of cocatalyst, in particular of the widely and successfully used methylaluminooxane compounds, is required in order to obtain a sufficiently active catalyst.

The term olefins here and hereinafter refers to α-olefins, diolefins and other ethylenically unsaturated monomers. Where the term 'polymerization of olefins' is used, this refers both to the polymerization of a single type of olefinic monomer and to the copolymerization of two or more olefins.

The object of the invention is to provide substituted Cp compounds whose presence as a ligand in a metal complex results in such complex, when used as catalyst component, requiring a smaller amount of cocatalyst, in particular a methylaluminooxane (MAO) compound, to be added than in the case of presence of a known substituted Cp compound in order yet to obtain a catalyst system of the same activity. This object is achieved according to the invention in that a di- or polysubstituted Cp is used as a ligand in which a group of the form -RDR'_n, where R is a bonding group between the Cp and the DR'_n group, D is a hetero atom chosen from group 15 or 16 of the Periodic System of the Elements, R' is a substituent and n is the number of R' groups bonded to D, is present as a substituent and in which at least one of the other substituents is an aralkyl group.

The presence of a Cp ligand with a group of the form - RDR'_n and at least one aralkyl group instead of methyl groups in a metal complex appears to give a more favourable relation between activity and amount of added cocatalyst, in particular MAO, than the known Cp compounds. From Synthesis, 1993, 684-686, tetramethylcyclopentadiene with ethyldimethylamine as fifth substituent is known. Not known or suggested is the favourable effect of its use in metal complexes, nor the amount of cocatalyst that is required to give these metal complexes a good catalytic effect. A further advantage of the use of di- or polysubstituted Cp's according to the invention as a ligand in a metal complex is that this results in a catalyst component offering enhanced activity in polyolefin polymerisation. In addition to the advantage of the aralkyl- substituted Cp compound as described in the foregoing, enhanced activity in the polymerization of olefins is found if such a polysubstituted Cp compound is present as the only Cp ligand in a metal complex in which the metal is not in its highest valency state.

Transition metal complexes in which the metal is not in the highest valency state, but in which the Cp ligand does not comprise a group of the form RDR'_n, as a rule are not active at all in olefin polymerizations. In the above-mentioned overview article in the J. of

Organomet. Chem. from 1994 it is even observed that 'An important feature of these catalyst systems is that tetravalent Ti centres are required for catalytic activity'. In this context it should be kept in mind that Ti is exemplary of the metals that are suitable as metal in the commonly used cyclopentadienyl-substituted metal complexes.

Corresponding complexes in which the Cp compound has not been substituted as described in the foregoing, appear to be unstable or, if they have been stabilized in another way, to yield less active catalysts than the complexes with substituted Cp compounds according to the invention, in particular in the polymerization of α-olefins. Further it appears that the Cp compounds according to the invention can stabilize highly reactive intermediates such as organometal hydrides, organometal boron hydrides, organometal alkyls and organometal cations. Moreover, they appear to be suitable as stable and volatile precursors for use in metal chemical deposition. The substituted Cp compound can also comprise several aralkyl groups as substituents.

The Cp compound preferably comprises at least two aralkyl groups as substituents. It has been found that with an increasing number of aralkyl substituents on the Cp compound, a metal complex in which the Cp compound is present as a ligand shows increasing activity as a catalyst component. These substituents may be identical as well as different. Besides the aralkyl group, whose presence as a substituent is required in the compound according to the invention, the Cp compound may contain further substituents on the other positions. Examples of these are alkyl groups, linear as well as branched and cyclic ones, and alkenyl and aralkyl groups. It is also possible for these to contain, apart from carbon and hydrogen, one or more hetero atoms from groups 14-17 of the Periodic System of the Elements, for example 0, N, Si or F, a hetero atom not being bound directly to the Cp. Examples of suitable groups are methyl, ethyl, (iso)propyl, sec- butyl, -pentyl, -hexyl and -octyl, (tert-)butyl and higher homologues, cyclohexyl.

The Cp compound may also be a heterocyclopentadiene compound. Here and hereinafter the term heterocyclopentadiene compound refers to a compound which is derived from cyclopentadiene but in which at least one of the C atoms in the 5-ring thereof has been replaced by a hetero atom, while the hetero atom can be selected from group 14, 15 or 16 of the Periodic System of the Elements. If more than one hetero atom is present in the 5-ring, these hetero atoms can be either identical or different. More preferably, the hetero atom is selected from group 15, especially preferably the hetero atom is phosphorus.

Metal complexes which are catalytically active if one of their ligands is a compound according to the invention are complexes of metals from groups 4- 10 of the Periodic System of the Elements and rare earths. For the Periodic System, see the new IUPAC notation to be found on the inside of the cover of the Handbook of Chemistry and Physics, 70th edition, 1989/1990. In this context, complexes of metals from groups 4 and 5 are preferably used as a catalyst component for polymerizing olefins, complexes of metals from groups 6 and 7 in addition also for metathesis and ring-opening metathesis polymerizations, and complexes of metals from groups 8-10 for olefin copolymerizations with polar comonomers, hydrogenations and carbonylations.

Substituted Cp compounds can, for instance, be prepared by reacting a halide of the substituting compound in a mixture of Cp compound and an aqueous solution of a base in the presence of a phase transfer catalyst. The term Cp compounds here refers to Cp itself and Cp already substituted in 1 to 3 positions, with the option of two substituents forming a closed ring. By means of the method according to the invention to be described in the following it is thus possible to convert unsubstituted compounds into singly or multiply substituted ones, but it is also possible for mono- or polysubstituted compounds derived from Cp to be substituted further, ring closure also being included in the options. Preferably, a virtually equivalent quantity of the halogenated substituting compound with respect to the Cp-compund is used. An equivalent quantity is understood as a quantity in moles which corresponds to the desired substitution multiplicity, for example 2 mol per mole of Cp compound, if disubsti- tution with the substituent in question is intended. Depending on the size and the associated steric hindrance of the substituting compounds it is possible to obtain trisubstituted to pentasubstituted Cp compounds. If a reaction with a tertiary halide of a substituting compound is carried out, as a rule only trisubstituted Cp compounds can be obtained, whereas with a primary and secondary halide of a substituting compound it is generally possible to achieve tetra- and often even pentasubstitution.

Aralkyl groups that are suitable as substituents are for instance benzyl, 2-phenylethyl , diphenylmethyl , triphenylmethyl, naphthalenemethyl , 3- phenylpropyl , l-phenyl-2-propyl , 4-tert-butylbenzyl , 2- and 3-paratolypropyl , but others can also be used. The Cp compound according to the invention is preferably substituted with 1, 2 of 3 aralkyl groups. The substituents are preferably used in the process in the form of their halides, by preference in the form of their bromides. When bromides are used it appears that a smaller amount of phase transfer catalyst suffices and that a greater yield of the desired compound is achieved.

By means of this process it is also possible, without intermediate isolation or purification, to obtain Cp compounds which are substituted with specific combinations of substituents. Thus, for example, disubstitution with the aid of a certain halide of a substituting compound can first be carried out and in the same reaction mixture a third substitution with a different substituent, by adding a second, different halide of a substituting compound to the mixture after a certain time. This can be repeated, so that it is also possible to prepare Cp derivatives having three or more different substituents.

The substitution takes place in a mixture of the Cp compound and an aqueous solution of a base. The concentration of the base in the solution is in the range between 20 and 80 wt.%. Hydroxides of an alkali metal, for example K or Na are highly suitable as a base. The base is present in an amount of 5-60, preferably 6-30 mol per mole of Cp compound. It has appeared that a substantial reduction of the reaction time can be achieved if the solution of the base is refreshed during the reaction for instance by first mixing the solution with the other components of the reaction mixture and after some time isolating the aqueous phase and replacing it by a fresh portion of solution of the base.

The substitution takes place at atmospheric or elevated pressure, for instance up to 100 MPa, which higher level is applied in particular if volatile components are present. The temperature at which the reaction takes place may vary within wide limits, for instance from -20 to 120°C, preferably between 10 and 50°C. Starting up the reaction at room temperature is usually a suitable step, after which the temperature of the reaction mixture can rise due to the heat released in the reaction.

The substitution takes place in the presence of a phase transfer catalyst which is able to transfer OH-ions from the aqueous phase to the organic phase containing Cp compound and substituting compound, the OH-ions reacting in the organic phase with a H-atom which can be split off from the Cp compound. Possible phase transfer catalysts to be used are quaternary ammonium, phosphonium, arsonium, stibonium, bismuthonium, and tertiary sulphonium salts. More preferably, ammonium and phosphonium salts are used, for example tricaprylmethylammonium chloride, commercially available under the name Aliquat 336 (Fluka AG, Switzerland; General Mills Co. , USA) and Adogen 464 (Aldrich Chemical Co., USA). Compounds such as benzyltriethylammonium chloride (TEBA) or benzyltriethylammonium bromide (TEBA-Br), benzyltrimethylammonium chloride, benzyltrimethylammonium bromide or benzyltrimethyl¬ ammonium hydroxide (Triton B), tetra-n-butylammonium chloride, tetra-n-butylammonium bromide, tetra-n-butyl¬ ammonium iodide, tetra-n-butylammonium hydrogen sulphate or tetra-n-butylammonium hydroxide and cetyltrimethylammonium bromide or cetyltrimethylammonium chloride, benzyltributyl-, tetra-n-pentyl-, tetra-n-hexyl- and trioctylpropylammonium chlorides and their bromides are likewise suitable. Usable phosphonium salts include, for example, tributylhexadecylphosphonium bromide, ethyltriphenylphosphonium bromide, tetraphenylphosphonium chloride, benzyltriphenylphosphonium iodide and tetrabutyl- phosphonium chloride. Crown ethers and cryptands can also be used as a phase transfer catalyst, for example 15-crown-5, 18-crown-6, dibenzo-18-crown-6, dicyclohexano-18-crown-6, 4,7,13,16,21-pentaoxa-l, 10- diazabicyclo[8.8.5]tricosane (Kryptofix 221), 4,7,13,18-tetraoxa-l,10-diazabicyclo[8.5.5]eicosane (Kryptofix 211) and 4,7,13,16,21,24-hexaoxa-l,10- diazabicyclo[8.8.8]-hexacosane ("[2.2.2]") and its benzo derivative Kryptofix 222 B. Polyethers such as ethers of ethylene glycols can also be used as a phase transfer catalyst. Quaternary ammonium salts, phosphonium salts, phosphoric acid triamides, crown ethers, polyethers and cryptands can also be used on supports such as, for example, on a crosslinked poly¬ styrene or another polymer. The phase transfer catalyst is used in an amount of 0.01 - 2 equivalents on the basis of the amount of Cp-compound.

In the implementation of the process the components can be added to the reactor in various sequences. After the reaction is complete, the aqueous phase and the organic phase which contains the Cp compound are separated. When necessary, the Cp compound is recovered from the organic phase by fractional distillation.

The di- or polysubstituted Cp-compounds according to the invention also comprise a substituent of the form -RDR'_n. The R group constitutes the bond between the Cp-compound and the DR'_n group. The length of the shortest bond between the Cp and D is critical in that, if the Cp compound is used as a ligand in a metal complex, it determines the accessibility of the metal to the DR'_n group, a factor which facilitates the desired intramolecular coordination. If the R group (or bridge) is too short, the DR'_n group may not be able to coordinate properly owing to ring tension. R is at least one atom long. The R' groups can each separately be a hydrocarbon radical with 1-20 carbon atoms (such as alkyl, aryl, aralkyl, etc.). Examples of such hydrocarbon radicals are methyl, ethyl, propyl, butyl, hexyl, decyl, phenyl, benzyl and p-tolyl. R' can also be a substituent which, in addition to or instead of carbon and/or hydrogen, comprises one or more hetero atoms from groups 14-16 of the Periodic System of the Elements. Thus a substituent can be a group comprising N, 0 and/or Si. R' should not be a cyclopentadienyl or a cyclopentadienyl-based group.

The R group can be a hydrocarbon group with 1-20 carbon atoms (such as alkylidene, arylidene, arylalkylidene, etc.). Examples of such groups are methylene, ethylene, propylene, butylene, phenylene, with or without a substituted side chain. The R group preferably has the following structure:

(-ER² ₂-)_p

where p = 1-4 and E represents an atom from group 14 of the Periodic System. The R² groups can each be H or a group as defined for R'. Thus the main chain of the R group can also comprise silicon or germanium besides carbon. Examples of such R groups are: dialkyl silylene, dialkyl germylene, tetra-alkyl disilylene or dialkyl silaethylene (-(SiR² ₂) (CH₂)-) . The alkyl groups (R²) in such a group preferably have 1 to 4 carbon atoms and more preferably are a methyl or ethyl group.

The DR'_n group comprises a hetero atom D chosen from group 15 or 16 of the Periodic System of the Elements and one or more substituents R' bound to D. The number of R' groups (n) is coupled to the nature of the hetero atom D, in the sense that n = 2 if D originates from group 15 and that n = 1 if D originates from group 16. Preferably, the hetero atom D is chosen from the group comprising nitrogen (N) , oxygen (0), phosphorus (P) or sulphur (S); more prefer¬ ably, the hetero atom is nitrogen (N) . The R' group is also preferably an alkyl, more preferably an n-alkyl group containing 1 - 20 C atoms. More preferably, the R' group is an n-alkyl containing 1 - 10 C atoms.

Another possibility is that two R' groups in the DR'_n group are joined to each other to form a ring-type structure (so that the DR'_n group may be a pyrrolidinyl group). The DR'_n group may bond coordinatively to a metal.

A Cp compound substituted with a group of the form RDR'_n as well as with at least one aralkyl group can be prepared by substituting a group of the form - RDR'_n on the substituted Cp compound described above, for instance via the following synthesis route.

In a first step of this route a substituted Cp compound is deprotonated by reaction with a base, sodium or potassium.

As base can be applied for instance organolithium compounds (R³Li) or organomagnesium compounds (R³MgX) , where R³ is an alkyl, aryl, or aralkyl group and X is a halide, for instance n-butyl lithium or i-propylmagnesium chloride. Potassium hydride, sodium hydride, inorganic bases, such as NaOH and KOH, and alcoholates of Li, K and Na can also be used as base. Mixtures of the above-mentioned compounds can also be used.

This reaction can be carried out in a polar dispersing agent, for instance an ether. Examples of ethers are tetrahydrofuran (THF) and dibutyl ether. Nonpolar solvents, such as for instance toluene, can also be used.

Next, in a second step of the synthesis route the cyclopentadienyl anion obtained reacts with a compound of the formula (R'_nD-R-Y) or (X-R-Sul), where D, R, R' and n are as defined in the foregoing. Y is a halogen atom (X) or a sulphonyl group (Sul). The halogen atom X may be for instance chlorine, bromine and iodine. The halogen atom X preferably is a chlorine or bromine atom. The sulphonyl group has the form - OS0₂R⁶, wherein R⁶ is a hydrocarbon radical containing 1 - 20 carbon atoms, such as alkyl, aryl, aralkyl. Examples of such hydrocarbon radicals are butane, pentane, hexane, benzene and naphthalene. R⁶ may also contain one or more hetero atoms from groups 14 - 17 of the Periodic System of the Elements, such as N, 0, Si or F, in addition to or instead of carbon and/or hydrogen. Examples of sulphonyl groups are: phenylmethanesulphonyl , benzenesulphonyl , 1-butanesulphonyl , 2 , 5-dichlorobenzenesulphonyl , 5-dimethylamino-l-naphthalenesulphonyl , pentafluoro- benzenesulphonyl , p-toluenesulphonyl , trichloromethane- sulphonyl, trifluoromethanesulphonyl , 2,4,6- triisopropylbenzenesulphonyl , 2,4,6- trimethylbenzenesulphonyl , 2-mesitylenesulphonyl , methanesulphonyl , 4-methoxybenzenesulphonyl , 1- naphthalenesulphonyl , 2-naphthalenesulphonyl , ethane- sulphonyl, 4-fluorobenzenesulphonyl and 1-hexadecane- sulphonyl. Preferably, the sulphonyl group is p- toluenesulphonyl or trifluoromethanesulphonyl.

If D is a nitrogen atom and Y is a sulphonyl group, the compound according to the formula (R'_nD-R-Y) is formed in situ by reacting an aminoalcohol compound (R'₂NR-OH) consecutively with a base (such as described above), potassium or sodium and a sulphonyl halide (Sul-X) .

The second reaction step can also be carried out in a polar solvent as described for the first step. The temperature at which the reaction is carried out is -60 to 80°C. Reactions with X-R-Sul and with R'_nD-R-Y in which Y is Br or I are usually carried out at a temperature between -20 and 20°C. Reactions with DR'_n-R-Y in which Y is CI are usually carried out at a higher temperature (10 to 80°C). The upper limit for the temperature at which the reactions are carried out is determined in part by the boiling point of the compound DR'_n-R-Y and that of the solvent used. After the reaction with a compound of the formula (X-R-Sul) another reaction is carried out with LiDR'_n or HDR'_n in order to replace X by a DR'_n functionality. This reaction is carried out at 20 to 80°C, optionally in the same dispersant as mentioned in the foregoing.

During the synthesis process according to the invention, geminal products may in part be formed. A geminal substitution is a substitution in which the number of substituents increases by 1, but in which the number of substituted carbon atoms does not increase. The amount of geminal products formed is low if the synthesis is carried out starting from a substituted Cp compound containing 1 substituent and increases as the substituted Cp compound contains more substituents. If sterically large substituents are present on the substituted Cp compound, geminal products are not, or are scarcely, formed. Examples of sterically large substituents are secondary or tertiary alkyl substituents. The amount of geminal product formed is also low if the second step of the reaction is carried out under the influence of a Lewis base whose conjugated acid has a dissociation constant for which pK_a is less than or equal to -2.5. The pK_a values are based on D. D. Perrin: Dissociation Constants of Organic Bases in Aqueous Solution, International Union of Pure and Applied Chemistry, Butterworths , London 1965. The values have been determined in an aqueous H₂S0₄ solution. Ethers can be mentioned as examples of suitable weak Lewis bases.

If geminal products have formed during the process according to the invention, said products can easily be separated from the nongeminal products by converting the mixture of geminally and nongeminally substituted products into a salt by reaction with potassium, sodium or a base, after which the salt is washed with a dispersant in which the salt of the nongeminal products is insoluble or sparingly soluble. The compounds mentioned above may be used as base.

Suitable dispersants are nonpolar dispersants, such as alkanes. Examples of suitable alkanes are: heptane and hexane. The substituted Cp compounds according to the invention are particularly suitable as a ligand in a metal complex, and when used as such they produce the above-described favourable effect that less cocatalyst is required in order to form with the complex a catalyst of a certain activity.

Metal complexes comprising as least one substituted cyclopentadiene compound as defined above appear to exhibit improved stability compared with similar complexes in which other Cp compounds are present as ligands, in particular if the metal in the complex is not in its highest valency state. Moreover, such complexes require less cocatalyst, as described in the foregoing. The invention therefore also relates to said metal complexes and to the use thereof as catalyst component for the polymerization of olefins.

Metal complexes which are catalytically active if one of their ligands is a compound according to the invention have already been specified in the foregoing.

The synthesis of metal complexes with the above-described specific Cp compounds as a ligand can take place according to the methods known per se for this purpose. The use of these Cp compounds does not require any adaptations of said known methods.

The polymerization of α-olefins, for example ethene, propene, butene, hexene, octene and mixtures thereof and combinations with dienes, can be carried out in the presence of the metal complexes with the Cp compounds according to the invention as ligand. Suitable in particular for this purpose are the complexes of transition metals which are not in their highest valency state, in which just one of the cyclopentadienyl compounds according to the invention is present as ligand and in which the metal is cationic during the polymerization. Said polymerizations can be carried out in the manner known for the purpose and the use of the metal complexes as catalyst component does not make any essential adaptation of these processes necessary. The known polymerizations are carried out in suspension, solution, emulsion, gas phase or as bulk polymerization. The cocatalyst usually applied is an organometal compound, the metal being chosen from Groups 1, 2, 12 or 13 of the Periodic System of the Elements. To be mentioned are for instance trialkylaluminium, alkylaluminium halides, alkylaluminooxanes (such as methylaluminoxanes) , tris(pentafluorophenyl ) borate, dimethylanilinium tetra(pentafluorophenyl ) borate or mixtures thereof. The polymerizations are carried out at temperatures between -50°C and +350°C, more particularly between 25 and 250°C. The pressures used are generally between atmospheric pressure and 250 MPa, for bulk polymerizations more particularly between 50 and 250 MPa, and for the other polymerization processes between 0.5 and 25 MPa. As dispersants and solvents, use may be made of, for example, hydrocarbons, such as pentane, heptane and mixtures thereof. Aromatic, optionally perfluorinated hydrocarbons, are also suitable. The monomer applied in the polymerization can also be used as dispersant or solvent.

The invention will be elucidated by means of the following examples, without being restricted thereto. For characterization of the products obtained the following analysis methods were used:

Gas chromatography was performed on a Hewlett Packard 5890 Series II with an HP Crosslinked Methyl Silicon Gum (25 m x 0.32 mm x 1.05 μm. ) column. Gas chromatography combined with mass spectrometry (GC-MS) was performed with a Fisons MD800, equipped with a quadrupole mass detector, autoinjector Fisons AS800 and CPSilδ column (30 m x -0.25 mm x 1 μm , low bleed). NMR was performed with a Bruker ACP200 (^XH = 200 MHz; ¹³C = 50 MHz) or Bruker ARX400 NMR (^XH = 400 MHz; ¹³C = 100

MHz). Metal complexes were characterized using a Kratos MS80 mass spectrometer or a Finnigan Mat 4610 mass spectrometer.

Example I

Preparation of di (2-phenylpropyl)cvclopentadiene

A double-walled reactor having a volume of 1 L, provided with baffles, condenser, top stirrer, thermometer and dropping funnel was charged with 600 g of clear 50% strength NaOH (7.5 mol), followed by cooling to 8°C. Then 20 g of Aliquat 336 (49 mmol) and 33 g (0.5 mol) of freshly cracked cyclopentadiene were added. The reaction mixture was stirred turbulently for a few minutes. Then 219 g of l-bromo-2-phenylpropane (1.1 mol) were added at once, cooling with water taking place at the same time. After 2 hours' stirring at room temperature the reaction mixture was heated to 70°C, followed by a further 6 hours' stirring. GC was used to show that at that instant 89% of di(2- phenylpropyl )cyclopentadiene were present. The product was distilled at a low pressure and a high temperature, after which 95.34 g (0.4 mol; 80%) of di(2- phenylpropyl )cyclopentadiene were obtained. Characterization took place with the aid of GC, GC-MS, ¹³C- and ^-H-NMR.

Experiment II

Preparation of 2-(N,N-dimethylamino)ethyl tosylate in situ

A solution of n-butyllithium in hexane (1 equivalent) was added at -10°C (dispensing time: 60 minutes) to a solution of 2-dimethylaminoethanol (1 equivalent) in d; y THF under dry nitrogen in a three- neck round-bottom flask provided with a magnetic stirrer and a dropping funnel. After all the butyllithium had been added, the mixture was brought to room temperature and stirred for 2 hours. The mixture was then cooled (-10°C), after which paratoluenesulphonyl chloride (1 equivalent) was added. The solution was then stirred for 15 minutes at this temperature before it was added to a cyclopentadienyl anion.

Comparable tosylates can be prepared in an analogous way. In a number of the examples below, a tosylate is coupled to alkylated Cp compounds in each case. During this coupling, geminal coupling also takes place in addition to the required substitution reaction. In nearly all cases it was possible to separate the geminal isomers from the nongeminal isomers by converting the nongeminal isomers into their sparingly soluble potassium salt, followed by washing of said salt with a solvent in which said salt is not soluble or is sparingly soluble.

Example III

Preparation of (dimethylaminoethyl )di ( 2- phenylpropyl)cyclopentadiene

12.5 mL of a 1.6M solution of n-butyllithium in hexane was added dropwise to a cooled (0°C) solution of di (2-phenylpropyl )cyclopentadiene (6.05 g; 20.0 mmol) in dry tetrahydrofuran (100 ml) under a nitrogen atmosphere in a 250 ml three-neck round-bottom flask provided with a magnetic stirrer and a dropping funnel. After stirring for 24 hours at room temperature, a solution of the 2-(dimethylaminoethyl )tosylate (20 mmol) in THF/hexane (see example IB) was added. After stirring for 18 hours, the conversion was found to be 90% and water (100 ml) was carefully added dropwise to the reaction mixture, after which the tetrahydrofuran was distilled off. The crude product was extracted with ether, after which the combined organic phase was dried (on sodium sulphate) and evaporated down. The residue was purified by means of a column containing silica gel, resulting in 5.98 g (80%) of

(dimethylaminoethyl )di (2-phenylpropyl )cyclopentadiene.

Example IV

Preparation of ( (dimethylaminoethyl )di (2-phenyl- propyl )cyclopentadienyl )titaniumdichloride

1.87 mL of a 1.6M solution of butyllithium in hexane were added to (dimethylaminoethyl)di (2-phenyl¬ propyl )cyclopentadiene (1.12 g, 3 mmol) dissolved in 20 mL of tetrahydrofuran at 0°C (ice bath). After 15 minutes' stirring this mixture was cooled down further to -78 degrees Celsius and a slurry, also cooled to -78 degrees Celsius, of Ti (III)C1₃ - 3THF (1.11 g, 3 mmol) in — lo —

20 mL of THF was added. The cooling bath was removed and the dark green solution formed was stirred for 72 hours at room temperature. After evaporation, 30 mL of petroleum ether (40-60) was added. Complete evaporation was again carried out, yielding a green powder (1.65 g) containing ( (dimethylaminoethyl)di(2-phenyl¬ propyl)cyclopentadienyl)titaniumdichloride.

Comparative Experiment A Preparation of ( (dimethylaminoethyl^cyclopentadienyl)- titaniumdichloride

The synthesis was carried out as in Example

IV, but now starting from:

1.37 g of (dimethylaminoethyl)cyclopentadiene (10 mmol), 6,2 mL of a 1.6M butyllithium solution in hexane, 3.7 g of TiCl₃.3THF (10 mmol). 2.60 g of powder containing (dimethylaminoethyl)cyclopentadienyl)- titaniumdichloride was obtained.

Examples V-VIII and Comparative Experiments B and C Ethene/octene batch copolymerization experiments

The copolymerization reactions of ethene with octene were carried out as follows:

600 ml of an alkane mixture (pentamethyl heptane or special boiling point solvent) were supplied to a 1.5-litre stainless steel reactor under dry nitrogen as reaction medium. Then the envisaged amount of dry octene (which may also be nil) was introduced into the reactor. Next the reactor was heated to the required temperature with stirring under the required ethene pressure.

25 ml of the alkane mixture as solvent were supplied to a 100-ml catalyst dispensing vessel. In this vessel the required amount of an Al-containing cocatalyst was pre-mixed for 1 minute with the required amount of metal complex.

This mixture was then supplied to the reactor and the polymerization started. The polymerization reaction was carried out isothermally. The ethylene pressure was kept constant at the set pressure. Upon completion of the required reaction time the ethene supply was stopped and the reaction mixture was drained off and quenched with methanol.

The reaction mixture with methanol was washed with water and HCl in order to remove the catalyst residues. Then the mixture was neutralized with NaHC0₃. Next, an antioxidant (Irganox 1076, TM) was added to the organic fraction for the purpose of stabilization of the polymer. The polymer was dried under vacuum at 70°C for 24 hours.

Capable of variation are:

- metal complex

- temperature

The catalyst obtained in example IV was used at two different temperatures and MAO/Ti ratios in polymerization experiments V-VIII. For the purpose of comparison the catalyst obtained in example A was used at the same two temperatures in polymerization experiments B and C. The actual conditions are stated in Table I.

TABLE I

4-. -1

o

10

* MAO: methyialuminoxane from Wltco

O H r s

VO 00

Claims

C L A I M S

1. Disubstituted or polysubstituted cyclopentadiene compound in which at least one substituent is of the form -RDR'_n, where R is a bonding group between the cyclopentadiene and the DR'_n group, D is a hetero atom chosen from group 15 or 16 of the Periodic System of the Elements, R' is a substituent and n is the number of R' groups bonded to D, and in which at least one of the other substituents is an aralkyl group.

2. Di- or polysubstituted cyclopentadiene compound according to claim 1, in which R has the structure (-ER² ₂-)_p where p = 1-4 and E is an atom from group 14 of the Periodic System.

3. Di- or polysubstituted cyclopentadiene compound according to any one of claims 1-2, in which D is chosen from the group comprising nitrogen (N), oxygen (0), phosphorus (P) or sulphur (S).

4. Di- or polysubstituted cyclopentadiene compound according to any one of claims 1-3, in which R' is an n-alkyl group containing 1-20 carbon atoms.

5. Metal complex in which at least one cyclopentadiene compound according to any one of claims 1-4 is present as a ligand.

6. Metal complex in which one cyclopentadiene compound according to any one of claims 1-4 is present as a ligand.

7. Metal complex according to claim 5 or 6, in which the metal is a metal from groups 4-10 of the Periodic System of the Elements and rare earths.

8. Application of the metal complex according to any one of Claims 5-7 as a catalyst component for the polymerization of α-olefins.

9. Application of the metal complex according to any one of Claims 5-7 as a catalyst component for the polymerization of α-olefins, the complex comprising a metal which is not in its highest valency state.