WO2000047586A1 - Metal complexes useful as polymerization catalyst - Google Patents

Abstract

A complex is disclosed having Formula (II), wherein M is vanadium or titanium; X represents an atom or group covalently or ionically bonded to M; T is the oxidation state of M and is [II], [III], [IV] or [V] in the case of vanadium and [II], [III] or [IV] in the case of titanium; b is the valency of the atom or group X; R1 to R7 are each independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl, substituted heterohydrocarbyl or SiR'¿3? where each R' is independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl and substituted heterohydrocarbyl, which is useful as a catalyst for the polymerisation of 1-olefins.

Description

METAL COMPLEXES USEFUL AS POLYMERIZATION CATALYST

The present invention relates to transition metal complex compounds, to polymerisation catalysts based thereon and to their use in the polymerisation and copolymerisation of olefins.

The use of certain transition metal compounds to polymerise 1 -olefins, for example, ethyl ene or propylene, is well established in the prior art. The use of Ziegler- Natta catalysts, for example, those catalysts produced by activating titanium halides with organometallic compounds such as triethylaluminium, is fundamental to many commercial processes for manufacturing polyolefins. Over the last twenty or thirty years, advances in the technology have led to the development of Ziegler-Natta catalysts which have such high activities that olefin polymers and copolymers containing very low concentrations of residual catalyst can be produced directly in commercial polymerisation processes. The quantities of residual catalyst remaining in the produced polymer are so small as to render unnecessary their separation and removal for most commercial applications. Such processes can be operated by polymerising the monomers in the gas phase, or in solution or in suspension in a liquid hydrocarbon diluent. Polymerisation of the monomers can be carried out in the gas phase (the "gas phase process"), for example by fluidising under polymerisation conditions a bed comprising the target polyolefin powder and particles of the desired catalyst using a fluidising gas stream comprising the gaseous monomer. In the so-called "solution process" the (co)polymerisation is conducted by introducing the monomer into a solution or suspension of the catalyst in a liquid hydrocarbon diluent under conditions of temperature and pressure such that the produced polyolefin forms as a solution in the hydrocarbon diluent. In the "slurry process" the temperature, pressure and choice of diluent are such that the produced polymer forms as a suspension in the liquid hydrocarbon diluent. These processes are generally operated at relatively low pressures (for example 10-50 bar) and low temperature (for example 50 to 150°C). In recent years the use of certain metallocene catalysts (for example biscyclopentadienylzirconiumdichloride activated with alumoxane) has provided catalysts with potentially high activity. However, metallocene catalysts of this type suffer from a number of disadvantages, for example, high sensitivity to impurities when used with commercially available monomers, diluents and process gas streams, the need to use large quantities of expensive alumoxanes to achieve high activity, and difficulties in putting the catalyst on to a suitable support.

Patent Application WO98/27124 discloses that ethylene may be polymerised by contacting it with certain iron or cobalt complexes of selected 2,6- pyridinecarboxaldehydebis(imines) and 2,6-diacylpyridinebis(imines). In J. Chem. Soc. (A), 1970, 2964-2966, oxo vanadium (IN) complexes of the general formula NO[2,6-bis- (l-(phenylimino)ethyl)pyridine]X2 where X is Cl or Br are disclosed, but no utility is mentioned.

An object of the present invention is to provide a novel catalyst suitable for polymerising and oligomerising monomers, for example, olefins such as α-olefins containing from 2 to 20 carbon atoms, and especially for polymerising ethylene alone, propylene alone, or for copolymerising ethylene or propylene with other 1 -olefins such as C₂.2o α-olefins. A further object of the invention is to provide an improved process for the polymerisation of olefins, especially of ethylene alone or the copolymerisation of ethylene or propylene with higher 1 -olefins to provide homopolymers and copolymers having controllable molecular weights. For example, using the catalysts of the present invention there can be made a wide variety of products such as, for example, liquid polyolefins, oligomers, linear α-olefins, branched α-olefins, resinous or tacky polyolefins, solid polyolefins suitable for making flexible film and solid polyolefins having high stiffness. The present invention provides a complex having the Formula (II)

Formula (I)

wherein M is vanadium or titanium; X represents an atom or group covalently or ionically bonded to M; T is the oxidation state of M and is [II], [III], [IN] or [N] in the case of vanadium and [II], [HI] or [IN] in the case of titanium; b is the valency of the atom or group X; R¹ to R⁷ are each independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl, substituted heterohydrocarbyl or SiR'₃ where each R' is independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl and substituted heterohydrocarbyl; but excluding NO[2,6-bis-(l-(phenylimino)ethyl)pyridine]X₂ where X is Cl or Br. Preferred are complexes of N[II], N[III] or Ti[HT|. In one embodiment at least one and preferably both of R⁴ and R⁶ is a hydrocarbyl group having at least two carbon atoms. Preferably at least one of R⁴ and R⁶ has from 2 to 12 carbon atoms, and more preferably from 3 to 10 carbon atoms. Preferred such groups for R⁴ and R⁶ are ethyl, isopropyl, t-butyl, phenyl or CH₂CH₂Ph.

R⁵ and R⁷ are preferably independently selected from substituted or unsubstituted alicyclic, heterocyclic or aromatic groups, for example, phenyl, 1-naphthyl, 2-naphthyl, 2-methylphenyl, 2-ethylphenyl, 2,6-diisopropylphenyl, 2,3-diisopropylphenyl,

2,4-diisopropylphenyl, 2,6-di-n-butylphenyl, 2,6-dimethylphenyl, 2,3-dimethylphenyl, 2,4-dimethylphenyl, 2-t-butylphenyl, 2,6-diphenylphenyl, 2,4,6-trimethylphenyl, 2,6- trifluoromethylphenyl, 4-bromo-2,6-dimethylphenyl, 3,5 dichloro2,6-diethylphenyl, and 2,6,bis(2,6-dimethylphenyl)phenyl, cyclohexyl and pyridinyl. In a preferred embodiment R⁵ is represented by the group "P" and R⁷ is represented by the group "Q" as follows:

Group P Group Q

wherein R¹⁹ to R²⁸ are independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl; when any two or more of R¹ to R⁴, R⁶ and R¹⁹ to R²⁸ are hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl, said two or more can be linked to form one or more cyclic substituents. The ring systems P and Q are preferably independently 2,6-hydrocarbylphenyl or fused-ring polyaromatic, for example, 1-naphthyl, 2-naphthyl, 1-phenanthrenyl and 8- quinolinyl.

Preferably at least one of R¹⁹, R²⁰, R²¹ and R²² is hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl. More preferably at least one of R¹⁹ and R²⁰, and at least one of R²¹ and R²², is hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl. Most preferably R¹⁹, R²⁰, R²¹ and R²² are all independently selected from hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl. R , R , R and R are preferably independently selected from methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert- butyl, n-pentyl, neopentyl, n-hexyl, 4-methylpentyl, n-octyl, phenyl and benzyl. R¹, R², R³, R⁴, R⁶, R¹⁹, R²⁰, R²¹, R²², R²³, R²⁵, R²⁶ and R²⁸ are preferably independently selected from hydrogen and Ci to C₈ hydrocarbyl, for example, methyl, ethyl, n-propyl, n-butyl, t-butyl, n-hexyl, n-octyl, phenyl and benzyl.

In one embodiment R²⁴ and R²⁷ are either both halogen or at least one of them has two or more carbon atoms.

In an alternative embodiment R⁵ is a group having the formula -NR²⁹R³⁰ and R⁷ is a group having the formula - R , wherein R to R are independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl; when any two or more of R to R , R and R to R are hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl, said two or more can be linked to form one or more cyclic substituents. Each of the nitrogen atoms is coordinated to the metal by a "dative" bond, ie a bond formed by donation of a lone pair of electrons from the nitrogen atom. The remaining bonds on each N atom are covalent bonds formed by electron sharing between the N atoms and the organic ligand as shown in the defined formula for the metal complex illustrated above. The atom or group represented by X in the compounds of Formula (I) can be, for example, selected from halide, sulphate, nitrate, thiolate, thiocarboxylate, BF₄ ^", PF₆ ^", hydride, hydrocarbyloxide, carboxylate, hydrocarbyl, substituted hydrocarbyl and heterohydrocarbyl, or β-diketonates. Examples of such atoms or groups are chloride, bromide, methyl , ethyl, propyl, butyl, octyl, decyl, phenyl, benzyl, methoxide, ethoxide, isopropoxide, tosylate, triflate, formate, acetate, phenoxide and benzoate. Preferred examples of the atom or group X in the compounds of Formula (I) are halide, for example, chloride, bromide; hydride; hydrocarbyloxide, for example, methoxide, ethoxide, isopropoxide, phenoxide; carboxylate, for example, formate, acetate, benzoate; hydrocarbyl, for example, methyl, ethyl, propyl, butyl, octyl, decyl, phenyl, benzyl; substituted hydrocarbyl; heterohydrocarbyl; tosylate; and triflate. Preferably X is selected from halide, hydride and hydrocarbyl. Chloride is particularly preferred.

Examples of complexes of the present invention include 2,6- diacetylpyridinebis(2,4,6-trimethylanil)NCl₃, 2,6-diacetylpyridinebis(2,4- dimethylanil)NCl₃, 2,6-diacetylpyridinebis(2-methylanil)NCl₃, 2,6- dibenzoylpyridinebis(2,4,6-trimethylanil)NCl₃ and 2,6-diacetylpyridinebis(2,4,6- trimethylanil)TiCl₃.

The present invention further provides a polymerisation catalyst comprising

(1) a nitrogen-containing vanadium compound having the Formula (I) as hereinbefore defined and including NO[2,6-bis-(l-(phenylimino)ethyl)pyridine]X where X is Cl or Br, and

(2) an activating quantity of at least one activator compound.

We have found that the polymerisation catalyst of the invention is particularly suitable for incorporating short chain and long chain branching into ethylene homopolymers, and can also provide α-olefins and copolymers of ethylene or propylene with other olefins such as hexene. With ethylene/hexene copolymerisation we have found that it is possible to obtain uniform Cβ incorporation. The activator compound for the catalyst of the present invention is suitably selected from organoaluminium compounds and hydrocarbylboron compounds. Suitable organoaluminium compounds include compounds of the formula A1R₃, where each R is independently Cι-d₂ alkyl or halo. Examples include trimethylaluminium (TMA), triethylaluminium (TEA), tri-isobutylaluminium (TIBA), tri-n-octylaluminium, methylaluminium dichloride, ethylaluminium dichloride, dimethylaluminium chloride, diethylaluminium chloride, ethylaluminiumsesquichloride, methylaluminiumsesquichloride, and alumoxanes. Alumoxanes are well known in the art as typically the oligomeric compounds which can be prepared by the controlled addition of water to an alkylaluminium compound, for example trimethylaluminium. Such compounds can be linear, cyclic or mixtures thereof. Commercially available alumoxanes are generally believed to be mixtures of linear and cyclic compounds. The cyclic alumoxanes can be represented by the formula [R¹ AlO]_s and the linear alumoxanes by the formula R¹⁷(R¹⁸AlO)_s wherein s is a number from about 2 to 50, and wherein R¹⁶, R¹⁷, and R¹⁸ represent hydrocarbyl groups, preferably Ci to Cβ alkyl groups, for example methyl, ethyl or butyl groups. Alkylalumoxanes such as methylalumoxane (MAO) are preferred.

Mixtures of alkylalumoxanes and trialkylaluminium compounds are particularly preferred, such as MAO with TMA or TIBA. In this context it should be noted that the term "alkylalumoxane" as used in this specification includes alkylalumoxanes available commercially which may contain a proportion, typically about 10wt%, but optionally up to 50wt%, of the corresponding trialkylaluminium; for instance, commercial MAO usually contains approximately 10wt% trimethylaluminium (TMA), whilst commercial MMAO contains both TMA and TIBA. Quantities of alkylalumoxane quoted herein include such trialkylaluminium impurities, and accordingly quantities of trialkylaluminium compounds quoted herein are considered to comprise compounds of the formula A1R additional to any A1R₃ compound incorporated within the alkylalumoxane when present. Examples of suitable hydrocarbylboron compounds are boroxines, trimethylboron, triethylboron, dimethylphenylammoniumtetra(phenyl)borate, trityltetra(phenyl)borate, triphenylboron, dimethylphenylammonium tetra(pentafluorophenyl)borate, sodium tetrakis[(bis-3 , 5-trifluoromethyl)phenyl]borate, H⁺(OEt₂)[(bis-3 , 5 -trifluoromethyl)phenyl]borate, trityltetra(pentafluorophenyl)borate and tris(pentafluorophenyl) boron.

In the preparation of the catalysts of the present invention the quantity of activating compound selected from organoaluminium compounds and hydrocarbylboron compounds to be employed is easily determined by simple testing, for example, by the preparation of small test samples which can be used to polymerise small quantities of the monomer(s) and thus to determine the activity of the produced catalyst. It is generally found that the quantity employed is sufficient to provide 0.1 to 20,000 atoms, preferably 1 to 2000 atoms of aluminium or boron per atom of metal M in the compound of Formula (I).

An alternative class of activators comprise salts of a cationic oxidising agent and a non-coordinating compatible anion. Examples of cationic oxidising agents include: ferrocenium, hydrocarbyl-substituted ferrocenium, Ag⁺, or Pb²⁺. Examples of non- coordinating compatible anions are BF₄ ^", SbClβ^", PF₆ ^", tetrakis(phenyl)borate and tetrakis(pentafluorophenyl)borate.

A further aspect of the present invention provides a polymerisation catalyst system comprising (1) a reaction product as defined above or a compound of the

Formula (I) or (II) and including NO[2,6-bis-(l-(phenylimino)ethyl)pyridine]X₂ where X is Cl or Br, (2) an activating quantity of at least one activator compound selected from organoaluminium and hydrocarbylboroncompounds, and (3) a neutral Lewis base. Neutral Lewis bases are well known in the art of Ziegler-Natta catalyst polymerisation technology. Examples of classes of neutral Lewis bases suitably employed in the present invention are unsaturated hydrocarbons, for example, alkenes (other than 1 -olefins) or alkynes, primary, secondary and tertiary amines, amides, phosphoramides, phosphines, phosphites, ethers, thioethers, nitriles, carbonyl compounds, for example, esters, ketones, aldehydes, carbon monoxide and carbon dioxide, sulphoxides, sulphones and boroxines. Although 1 -olefins are capable of acting as neutral Lewis bases, for the purposes of the present invention they are regarded as monomer or comonomer 1 -olefins and not as neutral Lewis bases per se. However, alkenes which are internal olefins, for example, 2-butene and cyclohexene are regarded as neutral Lewis bases in the present invention. Preferred Lewis bases are tertiary amines and aromatic esters, for example, dimethylaniline, diethylaniline, tributylamine, ethylbenzoate and benzylbenzoate. In this particular aspect of the present invention, components (1), (2) and (3) of the catalyst system can be brought together simultaneously or in any desired order. However, if components (2) and (3) are compounds which interact together strongly, for example, form a stable compound together, it is preferred to bring together either components (1) and (2) or components (1) and (3) in an initial step before introducing the final defined component. Preferably components (1) and (3) are contacted together before component (2) is introduced. The quantities of components (1) and (2) employed in the preparation of this catalyst system are suitably as described above in relation to the catalysts of the present invention. The quantity of the neutral Lewis Base [component (3)] is preferably such as to provide a ratio of component (l):component (3) in the range 100:1 to 1:1000, most preferably in the range 1:1 to 1:20. Components (1), (2) and (3) of the catalyst system can brought together, for example, as the neat materials, as a suspension or solution of the materials in a suitable diluent or solvent (for example a liquid hydrocarbon), or, if at least one of the components is volatile, by utilising the vapour of that component. The components can be brought together at any desired temperature. Mixing the components together at room temperature is generally satisfactory. Heating to higher temperatures e.g. up to 120°C can be carried out if desired, e.g. to achieve better mixing of the components. It is preferred to carry out the bringing together of components (1), (2) and (3) in an inert atmosphere (e.g. dry nitrogen) or in vacuo. If it is desired to use the catalyst on a support material (see below), this can be achieved, for example, by preforming the catalyst system comprising components (1), (2) and (3) and impregnating the support material preferably with a solution thereof, or by introducing to the support material one or more of the components simultaneously or sequentially. If desired the support material itself can have the properties of a neutral Lewis base and can be employed as, or in place of, component (3). An example of a support material having neutral Lewis base properties is poly(aminostyrene) or a copolymer of styrene and aminostyrene (ie vinylaniline).

The catalysts of the present invention can if desired comprise more than one of the defined compounds. Alternatively, the catalysts of the present invention can also include one or more other types of transition metal compounds or catalysts, for example, nitrogen containing catalysts such as those described in our copending applications PCT/GB98/02638. Examples of such other catalysts include 2,6- diacetylpyridinebis(2,4,6-trimethyl anil)FeCl₂.

The catalysts of the present invention can also include one or more other types of catalyst, such as those of the type used in conventional Ziegler-Natta catalyst systems, metallocene-based catalysts, monocyclopentadienyl- or constrained geometry based catalysts, or heat activated supported chromium oxide catalysts (eg Phillips-type catalyst).

The catalysts of the present invention can be unsupported or supported on a support material, for example, silica, alumina, MgCl₂ or zirconia, or on a polymer or prepolymer, for example polyethylene, polypropylene, polystyrene, or poly(aminostyrene). If desired the catalysts can be formed in situ in the presence of the support material, or the support material can be pre-impregnated or premixed, simultaneously or sequentially, with one or more of the catalyst components. The catalysts of the present invention can if desired be supported on a heterogeneous catalyst, for example, a magnesium halide supported Ziegler Natta catalyst, a Phillips type (chromium oxide) supported catalyst or a supported metallocene catalyst. Formation of the supported catalyst can be achieved for example by treating the transition metal compounds of the present invention with alumoxane in a suitable inert diluent, for example a volatile hydrocarbon, slurrying a particulate support material with the product and evaporating the volatile diluent. The produced supported catalyst is preferably in the form of a free- flowing powder. The quantity of support material employed can vary widely, for example from 100,000 to 1 grams per gram of metal present in the transition metal compound.

The present invention further provides a process for the polymerisation and copolymerisation of 1 -olefins, comprising contacting the monomeric olefin under polymerisation conditions with the polymerisation catalyst or catalyst system of the present invention. A preferred process comprises the steps of : a) preparing a prepolymer-based catalyst by contacting one or more 1 -olefins with a catalyst system, and b) contacting the prepolymer-based catalyst with one or more 1 -olefins, wherein the catalyst system is as defined above.

In the text hereinbelow, the term "catalyst" is intended to include "catalyst system" as defined previously and also "prepolymer-based catalyst" as defined above. The polymerisation conditions can be, for example, solution phase, slurry phase, gas phase or bulk phase, with polymerisation temperatures ranging from -100°C to +300°C, and at pressures of atmospheric and above, particularly from 140 to 4100 kPa. If desired, the catalyst can be used to polymerise ethylene under high pressure/high temperature process conditions wherein the polymeric material forms as a melt in supercritical ethylene. Preferably the polymerisation is conducted under gas phase fluidised bed or stirred bed conditions.

Suitable monomers for use in the polymerisation process of the present invention are, for example, ethylene and C_2-2o α-olefins, specifically propylene, 1-butene, 1- pentene, 1-hexene, 4-methylpentene-l, 1-heptene, 1-octene, 1-nonene, 1-decene, 1- undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1- heptadecene, 1-octadecene, 1-nonadecene, and 1-eicosene. Other monomers include methyl methacrylate, methyl acrylate, butyl acrylate, acrylonitrile, vinyl acetate, and styrene. Preferred monomers for homopolymerisation processes are ethylene and propylene. The catalysts and process of the invention can also be used for copolymerising ethylene or propylene with each other or with other 1 -olefins such as 1-butene, 1-hexene, 4- methylpentene-1, and octene, or with other monomeric materials, for example, methyl methacrylate, methyl acrylate, butyl acrylate, acrylonitrile, vinyl acetate, and styrene. Polymerisation of 1 -olefins with dienes, particularly non-conjugated dienes, such as 1,4 pentadiene, 1,5-hexadiene, cyclopentadiene and ethylene norbomadiene is also possible. In particular, ethylene/ 1-olefin/diene terpolymers may be made by the process of the invention where the diene is as above and the other 1 -olefin is preferably propylene. Irrespective of the polymerisation or copolymerisation technique employed, polymerisation or copolymerisation is typically carried out under conditions that substantially exclude oxygen, water, and other materials that act as catalyst poisons.

Also, polymerisation or copolymerisation can be carried out in the presence of additives to control polymer or copolymer molecular weights. The use of hydrogen gas as a means of controlling the average molecular weight of the polymer or copolymer applies generally to the polymerisation process of the present invention. For example, hydrogen can be used to reduce the average molecular weight of polymers or copolymers prepared using gas phase, slurry phase, bulk phase or solution phase polymerisation conditions. The quantity of hydrogen gas to be employed to give the desired average molecular weight can be determined by simple "trial and error" polymerisation tests.

The polymerisation process of the present invention provides polymers and copolymers," especially ethylene polymers, at remarkably high productivity (based on the amount of polymer or copolymer produced per unit weight of complex employed in the catalyst system). This means that relatively very small quantities of transition metal complex are consumed in commercial processes using the process of the present invention. It also means that when the polymerisation process of the present invention is operated under polymer recovery conditions that do not employ a catalyst separation step, thus leaving the catalyst, or residues thereof, in the polymer (e.g. as occurs in most commercial slurry and gas phase polymerisation processes), the amount of transition metal complex in the produced polymer can be very small.

Slurry phase polymerisation conditions or gas phase polymerisation conditions are particularly useful for the production of high or low density grades of polyethylene, and polypropylene. In these processes the polymerisation conditions can be batch, continuous or semi-continuous. Furthermore, one or more reactors may be used, e.g. from two to five reactors in series. Different reaction conditions, such as different temperatures or hydrogen concentrations may be employed in the different reactors. In the slurry phase process and the gas phase process, the catalyst is generally metered and transferred into the polymerisation zone in the form of a particulate solid either as a dry powder (e.g. with an inert gas) or as a slurry. This solid can be, for example, a solid catalyst system formed from the one or more of complexes of the invention and an activator with or without other types of catalysts, or can be the solid catalyst alone with or without other types of catalysts. In the latter situation, the activator can be fed to the polymerisation zone, for example as a solution, separately from or together with the solid catalyst. Preferably the catalyst system or the transition metal complex component of the catalyst system employed in the slurry polymerisation and gas phase polymerisation is supported on one or more support materials. Most preferably the catalyst system is supported on the support material prior to its introduction into the polymerisation zone. Suitable support materials are, for example, silica, alumina, zirconia, talc, kieselguhr, or magnesia. Impregnation of the support material can be carried out by conventional techniques, for example, by forming a solution or suspension of the catalyst components in a suitable diluent or solvent, and slurrying the support material therewith. The support material thus impregnated with catalyst can then be separated from the diluent for example, by filtration or evaporation techniques. Once the polymer product is discharged from the reactor, any associated and absorbed hydrocarbons are substantially removed, or degassed, from the polymer by, for example, pressure let-down or gas purging using fresh or recycled steam, nitrogen or light hydrocarbons (such as ethylene). Recovered gaseous or liquid hydrocarbons may be recycled to the polymerisation zone.

In the slurry phase polymerisation process the solid particles of catalyst, or supported catalyst, are fed to a polymerisation zone either as dry powder or as a slurry in the polymerisation diluent. The polymerisation diluent is compatible with the polymer(s) and catalyst(s), and may be an alkane such as hexane, heptane, isobutane, or a mixture of hydrocarbons or paraffins. Preferably the particles are fed to a polymerisation zone as a suspension in the polymerisation diluent. The polymerisation zone can be, for example, an autoclave or similar reaction vessel, or a continuous loop reactor, e.g. of the type well-know in the manufacture of polyethylene by the Phillips Process. When the polymerisation process of the present invention is carried out under slurry conditions the polymerisation is preferably carried out at a temperature above 0°C, most preferably above 15°C. The polymerisation temperature is preferably maintained below the temperature at which the polymer commences to soften or sinter in the presence of the polymerisation diluent. If the temperature is allowed to go above the latter temperature, fouling of the reactor can occur. Adjustment of the polymerisation within these defined temperature ranges can provide a useful means of controlling the average molecular weight of the produced polymer. A further useful means of controlling the molecular weight is to conduct the polymerisation in the presence of hydrogen gas which acts as chain transfer agent. Generally, the higher the concentration of hydrogen employed, the lower the average molecular weight of the produced polymer.

In bulk polymerisation processes, liquid monomer such as propylene is used as the polymerisation medium.

Methods for operating gas phase polymerisation processes are well known in the art. Such methods generally involve agitating (e.g. by stirring, vibrating or fluidising) a bed of catalyst, or a bed of the target polymer (i.e. polymer having the same or similar physical properties to that which it is desired to make in the polymerisation process) containing a catalyst, and feeding thereto a stream of monomer at least partially in the gaseous phase, under conditions such that at least part of the monomer polymerises in contact with the catalyst in the bed. The bed is generally cooled by the addition of cool gas (e.g. recycled gaseous monomer) and/or volatile liquid (e.g. a volatile inert hydrocarbon, or gaseous monomer which has been condensed to form a liquid). The polymer produced in, and isolated from, gas phase processes forms directly a solid in the polymerisation zone and is free from, or substantially free from liquid. As is well known to those skilled in the art, if any liquid is allowed to enter the polymerisation zone of a gas phase polymerisation process the quantity of liquid in the polymerisation zone is small in relation to the quantity of polymer present.. This is in contrast to "solution phase" processes wherein the polymer is formed dissolved in a solvent, and "slurry phase" processes wherein the polymer forms as a suspension in a liquid diluent.

The gas phase process can be operated under batch, semi-batch, or so-called "continuous" conditions. It is preferred to operate under conditions such that monomer is continuously recycled to an agitated polymerisation zone containing polymerisation catalyst, make-up monomer being provided to replace polymerised monomer, and continuously or intermittently withdrawing produced polymer from the polymerisation zone at a rate comparable to the rate of formation of the polymer, fresh catalyst being added to the polymerisation zone to replace the catalyst withdrawn form the polymerisation zone with the produced polymer.

For typical production of impact copolymers, homopolymer formed from the first monomer in a first reactor is reacted with the second monomer in a second reactor. For manufacture of propylene/ethylene impact copolymer in a gas-phase process, propylene is polymerized in a first reactor; reactive polymer transferred to a second reactor in which ethylene or other comonomer is added. The result is an intimate mixture of a isotactic polypropylene chains with chains of a random propylene/ethylene copolymer. A random copolymer typically is produced in a single reactor in which a minor amount of a comonomer (typically ethylene) is added to polymerizing chains of propylene.

Methods for operating gas phase fluidised bed processes for making polyethylene, ethylene copolymers and polypropylene are well known in the art. The process can be operated, for example, in a vertical cylindrical reactor equipped with a perforated distribution plate to support the bed and to distribute the incoming fluidising gas stream through the bed. The fluidising gas circulating through the bed serves to remove the heat of polymerisation from the bed and to supply monomer for polymerisation in the bed. Thus the fluidising gas generally comprises the monomer(s) normally together with some inert gas (e.g. nitrogen or inert hydrocarbons such as methane, ethane, propane, butane, pentane or hexane) and optionally with hydrogen as molecular weight modifier. The hot fluidising gas emerging from the top of the bed is led optionally through a velocity reduction zone (this can be a cylindrical portion of the reactor having a wider diameter) and, if desired, a cyclone and or filters to disentrain fine solid particles from the gas stream. The hot gas is then led to a heat exchanger to remove at least part of the heat of polymerisation. Catalyst is preferably fed continuously or at regular intervals to the bed. At start up of the process, the bed comprises fluidisable polymer which is preferably similar to the target polymer. Polymer is produced continuously within the bed by the polymerisation of the monomer(s). Preferably means are provided to discharge polymer from the bed continuously or at regular intervals to maintain the fluidised bed at the desired height. The process is generally operated at relatively low pressure, for example, at 10 to 50 bars, and at temperatures for example, between 50 and 120 °C. The temperature of the bed is maintained below the sintering temperature of the fluidised polymer to avoid problems of agglomeration. In the gas phase fluidised bed process for polymerisation of olefins the heat evolved by the exothermic polymerisation reaction is normally removed from the polymerisation zone (i.e. the fluidised bed) by means of the fluidising gas stream as described above. The hot reactor gas emerging from the top of the bed is led through one or more heat exchangers wherein the gas is cooled. The cooled reactor gas, together with any make-up gas, is then recycled to the base of the bed. In the gas phase fluidised bed polymerisation process of the present invention it is desirable to provide additional cooling of the bed (and thereby improve the space time yield of the process) by feeding a volatile liquid to the bed under conditions such that the liquid evaporates in the bed thereby absorbing additional heat of polymerisation from the bed by the "latent heat of evaporation" effect. When the hot recycle gas from the bed enters the heat exchanger, the volatile liquid can condense out. In one embodiment of the present invention the volatile liquid is separated from the recycle gas and reintroduced separately into the bed. Thus, for example, the volatile liquid can be separated and sprayed into the bed. In another embodiment of the present invention the volatile liquid is recycled to the bed with the recycle gas. Thus the volatile liquid can be condensed from the fluidising gas stream emerging from the reactor and can be recycled to the bed with recycle gas, or can be separated from the recycle gas and then returned to the bed.

The method of condensing liquid in the recycle gas stream and returning the mixture of gas and entrained liquid to the bed is described in EP-A-0089691 and EP-A- 0241947. It is preferred to reintroduce the condensed liquid into the bed separate from the recycle gas using the process described in our US Patent 5541270, the teaching of which is hereby incorporated into this specification.

When using the catalysts of the present invention under gas phase polymerisation conditions, the catalyst, or one or more of the components employed to form the catalyst can, for example, be introduced into the polymerisation reaction zone in liquid form, for example, as a solution in an inert liquid diluent. Thus, for example, the transition metal component, or the activator component, or both of these components can be dissolved or slurried in a liquid diluent and fed to the polymerisation zone. Under these circumstances it is preferred the liquid containing the component(s) is sprayed as fine droplets into the polymerisation zone. The droplet diameter is preferably within the range 1 to 1000 microns. EP-A-0593083, the teaching of which is hereby incorporated into this specification, discloses a process for introducing a polymerisation catalyst into a gas phase polymerisation. The methods disclosed in EP-A-0593083 can be suitably employed in the polymerisation process of the present invention if desired.

Although not usually required, upon completion of polymerisation or copolymerisation, or when it is desired to terminate polymerisation or copolymerisation or at least temporarily deactivate the catalyst or catalyst component of this invention, the catalyst can be contacted with water, alcohols, acetone, or other suitable catalyst deactivators a manner known to persons of skill in the art. Homopolymerisation of ethylene with the catalysts of the invention may produce so-called "high density" grades of polyethylene. These polymers have relatively high stiffness and are useful for making articles where inherent rigidity is required. Copolymerisation of ethylene with higher 1 -olefins (eg butene, hexene or octene) can provide a wide variety of copolymers differing in density and in other important physical properties. Particularly important copolymers made by copolymerising ethylene with higher 1 -olefins with the catalysts of the invention are the copolymers having a density in the range of 0.91 to 0.93. These copolymers which are generally referred to in the art as linear low density polyethylene, are in many respects similar to the so called low density polyethylene produced by the high pressure free radical catalysed polymerisation of ethylene. Such polymers and copolymers are used extensively in the manufacture of flexible blown film.

Propylene polymers produced by the process of the invention include propylene homopolymer and copolymers of propylene with less than 50 mole % ethylene or other alpha-olefin such as butene- 1, pentene-1, 4-methylpentene-l, or hexene- 1, or mixtures thereof. Propylene polymers also may include copolymers of propylene with minor amounts of a copolymerizable monomer. Typically, most useful are normally-solid polymers of propylene containing polypropylene crystallinity, random copolymers of propylene with up to about 10 wt.% ethylene, and impact copolymers containing up to about 20 wt.% ethylene or other alpha-olefin. Polypropylene homopolymers may contain a small amount (typically below 2 wt.%) of other monomers to the extent the properties of the homopolymer are not affected significantly.

Propylene polymers may be produced which are normally solid, predominantly isotactic, poly α-olefins. Levels of stereorandom by-products are sufficiently low so that useful products can be obtained without separation thereof. Typically, useful propylene homopolymers show polypropylene crystallinity and have isotactic indices above 90 and many times above 95. Copolymers typically will have lower isotactic indices, typically above 80-85.

Depending upon polymerisation conditions known in the art, propylene polymers with melt flow rates from below 1 to above 1000 may be produced in a reactor. For many applications, polypropylenes with a MFR from 2 to 100 are typical. Some uses such as for spunbonding may use a polymer with an MFR of 500 to 2000. Depending upon the use of the polymer product, minor amounts of additives are typically incorporated into the polymer formulation such as acid scavengers, antioxidants, stabilizers, and the like. Generally, these additives are incorporated at levels of about 25 to 2000 ppm, typically from about 50 to about 1000 ppm, and more typically 400 to 1000 ppm, based on the polymer.

In use, polymers or copolymers made according to the invention in the form of a powder are conventionally compounded into pellets. Examples of uses for polymer compositions made according to the invention include use to form fibres, extruded films, tapes, spunbonded webs, moulded or thermoformed products, and the like. The polymers may be blown into films, or may be used for making a variety of moulded or extruded articles such as pipes, and containers such as bottles or drums. Specific additive packages for each application may be selected as known in the art. Examples of supplemental additives include slip agents, anti-blocks, anti-stats, mould release agents, primary and secondary anti-oxidants, clarifiers, nucleants, uv stabilizers, and the like. Classes of additives are well known in the art and include phosphite antioxidants, hydroxylamine (such as N,N-dialkyl hydroxylamine) and amine oxide (such as dialkyl methyl amine oxide) antioxidants, hindered amine light (uv) stabilizers, phenolic stabilizers, benzofuranone stabilizers, and the like. Various olefin polymer additives are described in U.S. patents 4,318,845, 4,325,863, 4,590,231, 4,668,721, 4,876,300, 5,175,312, 5,276,076, 5,326,802, 5,344,860, 5,596,033, and 5,625,090.

Fillers such as silica, glass fibers, talc, and the like, nucleating agents, and colourants also may be added to the polymer compositions as known by the art. The present invention is illustrated in the following Examples.

EXAMPLE 1

1.1 - Preparation of 2.6-diacetylpyridinebis(2-methylani0

To a solution of 2,6-diacetylpyridine (0.607g; 3.72 mmol) in absolute ethanol (20ml) was added 2-methylaniline (lg; 2.5 eq.). After the addition of 2 drops of acetic acid (glacial) the solution was refluxed overnight. Upon cooling to room temperature the product crystallised from ethanol. The product was filtered, washed with cold ethanol and dried in a vacuum oven (50°C) overnight. The yield was 0.42g (33%). 1H NMR(CDC1₃): 8.48 (d, 2H, pyrH), 7.91 (t, 1H, pyrH),7.28 (m, 4H, ArH), 7.10 (m,2H, ArH), 6.75 (m, 2H, AiH), 2.42 (s, 6H,

2.20 (s, 6H, CH,). 1.2 - Preparation of 2.6-diacetylpyridinebis(2-methylanil)NCK.

NC1₃THF₃ (219mg; 0.586 mmol) and the 2,6-diacetylpyridinebis(2-methylanil) (200 mg; 0.586mmol) were weighed into a schlenk tube, then 10ml of THF were added. The reaction mixture was refluxed for five minutes, which caused precipitation of a pink solid and then allowed to reach room temperature. After stirring over night the resultant suspension was filtered via canula and the pink precipitate washed with toluene (10 cm³) and dried in vacuo. The yield of 2,6-diacetylpyridinebis(2-methylanil)VCl₃ was 241mg (82 %).

EXAMPLE 2

2.1 - Preparation of 2.6-diacetylpyridinebis(2.4-dimethylanil

The procedure was as for Example 1.1 except that 2,4-dimethyl aniline was used instead of 2-methylaniline. The yield was 75% of theoretical. 1H ΝMR(CDC1₃): 8.41, 7.90, 7.05, 6.90, 6.55, (m, 9H, ArH, pyrH), 2.36 (m, 6Η, N=CCH₃, 6H, CCH.), 2.13 (s, 6H, CCH₃). Mass spectrum: m/z 369 [M]⁺.

2.2 - Preparation of 2.6-diacetylpyridinebis(2.4-dimethylanil)NC

NC1₃THF₃ (202 mg; 0.54mmol) and the 2,6-diacetylpyridinebis(2,4-dimethylanil) (200 mg; 0.54mmol) were weighed into a schlenk tube, then 15 ml of THF were added. The reaction mixture was refluxed for five minutes, which caused precipitation of a brown solid and then allowed to reach room temperature. After stirring over night the resultant suspension was filtered via canula and the brown precipitate washed with toluene (10 cm³) and dried in vacuo. The yield of 2,6-diacetylpyridinebis(2,4-dimethylanil)NCl₃ was 145mg (51 %). EXAMPLE 3

3.1 - Preparation of 2.6-diacetylpyridinebis(2.4.6-trimethylanil To a toluene (150ml) solution of 2,6-diacetylpyridine (2g; 12.3mmol) in a single neck 250cm³ round bottom flask was added 2,4,6-dimethyl aniline (5.16cm³; 36.8 mmol). Toluene sulphonic acid-monohydrate (0. Ig) was added to the solution and the flask connected in series to a Dean-Stark apparatus and water cooled condenser. The reaction mixture was refluxed for 20 hours during which the produced water from the condensation reaction was collected in the Dean-Stark apparatus. Upon cooling to room temperature the volatile components of the reaction mixture were removed in vacuo and the product crystallised from methanol. The product was filtered, washed with cold methanol and dried in a vacuum oven (50°C) overnight. NMR and IR revealed the product to be exclusively 2,6-diacetylpyridinebis(2,4,6-trimethylanil) The yield was 4.23g (87 %).

3.2 - Preparation of 2.6-diacetylpyridinebisf2.4.6-trimethylanil NC NC1₃THF₃ (188mg; O.503mmol) and the 2,6-diacetylpyridinebis(2,4,6-trimethylanil) (200mg; 0.503mmol) were weighed into a schlenk tube, then 10 ml of THF were added. The reaction mixture was refluxed for five minutes, which caused precipitation of a green-brown solid and then allowed to reach room temperature. After stirring over night the resultant suspension was filtered via canula and the green precipitate washed with toluene (10 cm³) and dried in vacuo. The yield of 2,6-diacetylpyridinebis(2,4,6- trimethylanil)NCl₃ was 205mg (73 %). EXAMPLE 4

4.1 - Preparation of 2.6-dibenzoylpyridinebisf2.4.6-trimethylanil NC NC1₃THF₃ (72mg; 0.192mmol) and the 2,6-dibenzoylpyridinebis(2,4,6-trimethylanil) (lOOmg; 0.192mmol) were weighed into a schlenk tube, then 10 ml of THF were added. The reaction mixture was refluxed for five minutes, which caused precipitation of a green solid and then allowed to reach room temperature. After stirring over night the resultant suspension was filtered via canula and the green precipitate washed with toluene (10cm³) and dried in vacuo. The yield of 2,6-dibenzoylpyridinebis(2,4,6-trimethylanil)NCl was 57 mg (44 %). EXAMPLE 5 5.1 - Preparation of 2.6-diacetylpyridinebisf2.4.6-trimethylanil)TiC

TiCl₃THF₃ (186mg; O.503mmol) and the 2,6-diacetylpyridinebis(2,4,6-trimethylanil) (200mg; 0.503mmol) were weighed into a schlenk tube, then 10ml of THF were added. The reaction mixture was refluxed for five minutes, which caused precipitation of a metallic turquoise solid and then allowed to reach room temperature. After stirring over night the resultant suspension was filtered via canula and the green precipitate washed with toluene (10cm³) and dried in vacuo. The yield of 2,6-diacetylpyridinebis(2,4,6- trimethylanil)TiCl₃ was 215mg (78 %). EXAMPLE 6

6.1 - Preparation of 2.6-diacetylpyridinebisf2.6-diisopropylaniD

To a solution of 2,6-diacetylpyridine (6.1g, 37mmol) in toluene (150 ml) was added 2,6- diisopropylaniline (21.5ml, 114mmol) and p-toluenesulfonic acid monohydrate (200mg). The flask was connected in series to a Dean-Stark apparatus and water cooled condenser. The reaction mixture was refluxed overnight during which the produced water from the condensation reaction was collected in the Dean-Stark apparatus. Upon cooling to room temperature the volatile components of the reaction mixture were removed in vacuo and the resulting residue was washed with methanol to provide a yellow solid. NMR and IR revealed the solid to be exclusively the title compound in 85 % yield (15.2g). IRData : niminesuetch = 1644 (m) cm^"1

6.2 - Preparation of 2.6-diacetylpyridinebis(2.6-diisopropylanil)NCU NC1₃THF₃ (1.12g; 3.Ommol) and the 2,6-diacetylpyridinebis(2,6-diisoρroρylanil) (1.45g; 3. Ommol) were weighed into a schlenk tube and THF (40ml) was added. The solution was refluxed for 30 minutes. A pink precipitate was observed to form and the reaction was cooled to room temperature and stirred overnight. The precipitate was isolated as the title compound (pink powder) by filtration under nitrogen atmosphere. Yield = 51 % (l.lg).

IR Data : niminestretch = 1576 (m) cm^'1

SCHLENK TUBE POLYMERISATION TESTS EXAMPLE 7 The polymerisation tests shown in the Table below were were carried out using the following procedure. For runs 7.1 to 7.3 the catalyst of Example 3.2 and cocatalyst (methylalumoxane - "MAO") was added to a Schlenk tube and dissolved in toluene (20ml). The tube was purged with ethylene and the contents were mechanically stirred and maintained under 1 bar ethylene for the duration of the polymerisation. The polymerisation was terminated by the addition of 10% isopropanol in toluene and then aqueous hydrogen chloride. The produced solid polyethylene was filtered off, washed with aqueous hydrogen chloride and subsequently methanol and dried in a vacuum oven at 50°C.

In Runs 7.4-7.5 the catalyst of Example 1 under the same conditions was used. In Run 7.6 the catalyst of Example 2 under the same conditions was used. Run 7.7 was conducted under the same conditions with the catalyst of example 5. The same catalyst did not show any activity when MAO was used as a cocatalyst.

The results of the polymerisation tests are summarised in Table 1:

Table 1 Notes on Table 1 :

based on atoms of aluminium. The MAO was supplied by Witco as a 10%) solution in toluene.

** - mainly a-olefins: primarily 1-dodecene and 4- or 5-dodecene # - mainly a-olefins: primarily 1-dodecene

Table 2 : NMR results for example 7.1

As a comparative example NC1₃ was mixed with MAO (1 :250 = N: Al), but the vanadium chloride was not soluble under these conditions and no polymerisation occurred. In another run NC1₃(THF)₃ was used with MAO as a cocatalyst (1:250). Although this time the reaction mixture was soluble in toluene, no activity was observed. However when mixing NC1₃(THF)₃ with MeAlCl₂ good activity was obtained (373 gmmorV^ar^"1).

In another comparative example TiCl₃(THF)₃ was mixed with 1000 equivalents of MeAlCl₂. No activity was obtained.

EXAMPLE 8 - Homogeneous catalyst system, copolymerisation with hexene

The reactor was charged with MAO scavenger (3ml, 1.5M in toluene, 4.5mmol), hex-1-ene (100ml) and isobutane (400ml). After heating to 80°C, ethylene was admitted such that the total pressure was increased from 10.8 bar to 18.8 bar. In a separate vessel, precatalyst from Example 3.2 above (5mg, 9.6mmol) was dissolved in toluene (23ml) and activated by addition of MAO (7ml, 1.5M, 10.5 mmol, V:A1 = 1:1167). An aliquot of this catalyst solution (10ml, 3.2mmol) was injected into the reactor and the kinetic profile was monitored over 30min. Initially a very high exotherm was observed (increase in reactor temperature from 80°C to 95°C), but the corresponding high ethylene flow rate (2Lmin^'1) decayed rapidly to only -O^Lmin^"1 after 30min. After drying overnight under vacuum, 20.2g of polymer was isolated giving an average activity of 1562.5g mmol^'Vbar^"1. DSC analysis showed the melting point to be 114.3°C. The polymer has been analysed using 1H NMR as a solution in p-xylene-dw and ¹³C NMR as a solution in C2D₂Cl_t l,2,4-trichlorobenzene. The 1H spectrum was acquired at 110°C and the ¹³C spectrum at 130°C. The ¹³C spectrum shows that the sample contains largely isolated butyl branches. There are some minor peaks present which have not been assigned. Some of these will be due to adjacent hexene- 1 units in the polymer. There is a peak at around 33ppm and another of similar intensity at around 13.5ppm which may be due to internal olefins. There is little evidence for the structure with a methyl branch at the 5 position relative to the chain end (see below) which is usually seen when significant amounts of internal olefins are present.

Table 3 - NMR analysis for polymer formed in Example 8

Table 4 - ΝMR analysis of product from Example 9.2 GPC analysis shows M_w = 4166, M_n = 1879, M_w/M„ = 2.22. Hence the polymer is of low molecular weight, but very narrow polydispersity. EXAMPLE 9 - SUPPORTED CATALYST. CO-POLYMERISATION

9.1 - Preparation of MAO on ES70X

Toluene (200ml) was added to a vessel containing silica (ES70X grade, calcined at 200°C overnight, 20.5g after calcination) under an inert atmosphere. The slurry was mechanically stirred and MAO (1.5M, 62.1 mmol, 41.4ml) was added via syringe. The mixture was stirred for 1 hour at 80°C before removing excess toluene and drying under vacuum to obtain 15%wΛv MAO on silica in quantitative yield.

9.2 - Supported catalyst system, copolymerisation with hexene

The reactor was charged with TiBAl scavenger (3mL, 1.0M in toluene, 3mmol), hex-1-ene (100ml) and isobutene (400ml). After heating to 80°C, ethylene was admitted such that the total pressure was increased from 13.0 bar to 21.0 bar. In a separate vessel, precatalyst from Example 3.2 above (15mg, 28.8mmol) was mixed with MAO on silica (l.Og, SG313/1 : 15% w/w MAO on silica) and toluene (10ml) was added. The molar ratio of Al : V for the mixture was 90 : 1. The slurry was shaken thoroughly and stood for 30min : a colour change was noted from pale green to red/brown. An aliquot of the supported catalyst (3.3ml, 9.6mmol) was injected into the reactor and the kinetic profile was monitored over 120min. A gentle activation was noted and an ethylene flow of 1.1 Lmin^"1 after 5 min decayed linearly to a flow of 0.2 Lmin^"1 after 120min. After drying overnight, 50g of polymer was isolated, giving an average activity of 325.5gmmoι^"1h^"1bar^"1. DCS analysis showed the melting point to be 110°C. GPC analysis shows M_w = 14000, M„ = 1700, PD = 8.0.

The sample was analysed using 1H NMR as a solution in p-xylene-dio and ¹³C NMR as a solution in C₂D₂Cl₄/l,2,4-trichlorobenzene. The 1H spectrum was acquired at 110°C and the ¹³C spectrum at 130°C. The ¹³C spectrum is very similar to that of the previous sample, R8392. It shows that the sample contains largely isolated butyl branches although there are low levels of 1,3 and 1,5 structures detected (adjacent hexenes and hexene-ethylene-hexene structures). Other minor peaks are probably associated with the vinylidene and internal olefins.

The level of adjacent hexenes appears to be quite low compared to polymers with this level of branching prepared with different catalyst.

EXAMPLE 10 - SUPPORTED CATALYST. HOMOPOLYMERISATIOΝ

The reactor (1L) was heated under flowing nitrogen for 1 hour at 80°C before being cooled to 30°C. Tri-isobutyl aluminium scavenger (3ml, 1M in toluene, 3mmol), and isobutane (500ml) were added. The reactor was closed and heating to 80°C. Ethylene was admitted such that the total pressure was increased from 14.5 bar to 23.5 bar (8 bar over pressure of ethylene).

In a separate vessel, precatalyst from Example 3.2 above (5mg, 9.6mmol) was mixed with MAO/ES70X silica (0.3g, SG313/1 : 15 % w/w MAO on silica) and toluene (10ml) was added. The molar ratio of Al : N for the mixture was 90 : 1. The slurry was shaken thoroughly and stood for 90 min: a colour change was noted from pale green to red/brown. The catalyst slurry was injected directly into the reactor. The activity of the catalyst gradually increased and reached a maximum after 10 minutes (~ IL/min ethylene uptake). This decreased to ~ 0.2L/min after 1 hour. The reaction was allowed to proceed for 60 minutes. The polymer was recovered by venting the reactor and purging with nitrogen. After drying overnight under vacuum, 40g of polymer was isolated giving an average activity of 527 gmmor¹h^"1bar^"1.

GPC analysis of the product showed Mw = 28 000, Mn = 2 500, PD = 11.2

EXAMPLES 11 - 16

Supported catalyst system, homopolymerisation

Results for Examples 11 - 16 are presented in Tables 5a and 5b. A general procedure for supported homopolymerisations is given as follows : The reactor (1L) was heated under flowing nitrogen for 1 hour at 80°C before being cooled to 30°C. Tri-isobutyl aluminium scavenger (3ml, 1M in toluene, 3mmol), and isobutane (500ml) were added. The reactor was closed and heated to 80°C, ethylene was admitted such that the total pressure was increased by the required amount (between 2 and 21.5 bar over pressure as described in Table 5a). In example 16, 1.5 bar of H₂ gas was admitted into the reactor prior to charging with ethylene. In a separate vessel, precatalyst (from the relevent Example as described in Table 5a (10 mmol) was mixed with MAO/ES70X silica (0.33 g, prepared as described in Example 9.1, 15 % w/w MAO on silica) and toluene (10 mL) was added. The mixture was shaken thoroughly and the catalyst particles were allowed to settle forming a coloured solid beneath the colourless toluene supematent. The catalyst was shaken again to form a slurry with the toluene and the mixture was injected directly into the reactor. The reaction was allowed to proceed for 60 minutes before terminating by shutting off the ethylene supply and venting the reactor pressure. Recovered polymer was dried overnight under vacuum, before weighing and submitting for analysis.

Table 5a - Examples 11 -16: ethylene homo-polymerisation

Table 5b - Product analysis for examples 11 - 16

EXAMPLES 17 - 19 Supported catalyst system, copolymerisation with hexene

Results for Examples 17 - 19 are presented in Tables 6a and 6b. A general procedure for supported copolymerisations with hex-1-ene is given as follows :

The reactor was charged with TiBAl scavenger (3mL, 1.0M in toluene, 3mmol), hex-1-ene (100ml) and isobutene (400ml). The reactor was closed and heated to 80°C. Ethylene was admitted such that the total pressure was increased by the required amount (10 bar over pressure as described in Table 6a). In a separate vessel, precatalyst (from the rel event Example as described in Table 6a) (10 mmol) was mixed with MAO/ES70X silica (0.33g, prepared as described in Example 9.1, 15 % w/w MAO on silica) and toluene (10 ml) was added. The mixture was shaken thoroughly and the catalyst particles were allowed to settle forming a coloured solid beneath the colourless toluene supematent. The catalyst was shaken again to form a slurry with the toluene and the mixture was injected directly into the reactor. The reaction was allowed to proceed for 60 minutes before terminating by shutting off the ethylene supply and venting the reactor pressure. Recovered polymer was dried overnight under vacuum, before weighing and submitting for analysis.

Table 6a - Examples 17 - 19 : ethylene/hexene co-polymerisation

Table 6b - Product analysis for examples 17 - 19

EXAMPLE 20

Gas phase homopolvmerisation using a supported vanadium catalyst

20.1 - Preparation of the supported catalyst

2,6-diacetylpyridinebis(2,6-diisopropylanil)VCl₂ (prepared as described in Example 6, 30mg) was mixed as a solid with MAO/silica (2g, prepared as described in Example 9.1). Pentane (15ml) was added and the mixture was shaken before standing for 45 min, before removal of solvent under vacuum.

20.2 - Polymerisation Tests - Comparative Example 26 and Example 27 The reagents used in the polymerisation tests were: ethylene Grade 3.5 (supplied by Air Products) and trimethylaluminium (1 M in hexanes, supplied by Aldrich).

A 3 litre reactor was baked out under flowing nitrogen for at least 1 hour at

80°C before powdered sodium chloride (300g, predried under vacuum, 160°C, >4 hours) was added. The sodium chloride was used as a fluidisable/stirrable start-up charge powder for the gas phase polymerisation. Trimethyl aluminium (3ml, 2M in hexanes) was added to the reactor and was boxed in nitrogen. The alkyl aluminium was allowed to scavenge for poisons in the reactor for between Vi - 1 hour before being vented using 4 x 4 bar nitrogen purges. The reactor was charged with 8 bar ethylene and heated to 80°C prior to injection of the catalyst composition. The supported catalyst (0.42g, prepared as in Example 20.1 above) was injected under nitrogen. No polymerisation activity was observed. Further supported catalyst was injected (0.42g) followed by TMA (3 ml, 1M in hexanes). An exothermic reaction was observed and polymerisation activity recorded. The polymerisation test was allowed to continue for 4 hours before being terminated by purging the reactants from the reactor with nitrogen and reducing the temperature to < 30°C. The produced polymer was washed with water to remove the sodium chloride, then with acidified methanol (50ml HC1/2.5L methanol) and finally with water/ethanol (4: 1 v/v). The polymer was dried under vacuum, at 40°C, for 16 hours. 2.7 g of polyethylene was recovered corresponding to an activity of 5 g/mmol/h/bar. The polymer was analysed by GPC and was found to have the following properties : Mw = 239 000; Mn = 4000; Mw/Mn = 59.8

EXAMPLE 21

Propylene polymerisation using non-supported vanadium catalysts

General procedure : In a nitrogen dry-box the vanadium complex pro-catalyst (24 mmol) was weighed into a round-bottom flask and toluene was added (40 ml). The solution was stirred at room temperature for 5 minutes, or until a homogenous solution was formed and 10wt% MAO in toluene (4 ml, 290 eq.) was added. The flask was transferred to a Schlenk line and the solution was placed in an ice bath, or an oil bath at 60°C (Table 7) and stirred for 15 minutes under nitrogen at 700 rpm. The vessel was purged with propylene three times and a 0.75 bar propylene over-pressure was then maintained for the duration of the run. After one hour stirring at 700 rpm, the flask was evacuated and refilled with nitrogen three times and allowed to warm/cool to room temperature. The reaction was quenched by slowly adding 10% HC1 in methanol (5 ml). The aqueous layer was separated, the toluene fraction was dried (MgSO₄) and the solvent was removed to provide the product as an oily residue (Note : products < \_ were lost during removal of solvent). Results are given in Table 7.

Table 7 - Results for Example 21

Claims

Claims

1. A complex having the Formula (I)

Formula (I)

wherein M is vanadium or titanium; X represents an atom or group covalently or ionically bonded to M; T is the oxidation state of M and is [II], [III], [IN] or [N] in the case of vanadium and [II], [III] or [IN] in the case of titanium; b is the valency of the atom or group X; R¹ to R⁷ are each independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl, substituted heterohydrocarbyl or SiR'₃ where each R' is independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl and substituted heterohydrocarbyl; but excluding NO[2,6-bis-(l-(phenylimino)ethyl)pyridine]X₂ where X is Cl or Br. 2. Complex according to claim 1 wherein R⁵ and R⁷ are independently selected from substituted or unsubstituted alicyclic, heterocyclic or aromatic groups, for example, phenyl, 1-naphthyl, 2-naphthyl, 2-methylphenyl, 2-ethylphenyl, 2,6-diisopropylphenyl, 2,3-diisopropylphenyl, 2,4-diisopropylphenyl, 2,6-di-n-butylphenyl, 2,6-dimethylphenyl, 2,3-dimethylphenyl, 2,4-dimethylphenyl, 2-t-butylphenyl, 2,6-diphenylphenyl, 2,4,6- trimethylphenyl,

2,6-trifluoromethylphenyl, 4-bromo-2,6-dimethylphenyl, 3,5 dichloro2,6-diethylphenyl, and 2,6,bis(2,6-dimethylphenyl)phenyl, cyclohexyl and pyridinyl.

3. Complex according to claim 1 wherein R⁵ is represented by the group "P" and R⁷ is represented by the group "Q" as follows:

Group P Group Q

wherein R¹⁹ to R²⁸ are independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl; when any two or more of R¹ to R⁴, R⁶ and R¹⁹ to R²⁸ are hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl, said two or more can be linked to form one or more cyclic substituents.

4. Complex according to claim 3 wherein R¹, R², R³, R⁴, R⁶, R¹⁹, R²⁰, R²¹, R²², R²³, R , R and R are each independently selected from hydrogen and Ci to C₈ hydrocarbyl, preferably methyl, ethyl, n-propyl, n-butyl, n-hexyl, n-octyl, phenyl and benzyl.

5. Complex according to claim 3 or 4 wherein R²⁴ and R²⁷ are either both halogen or at least one of them has two or more carbon atoms.

6. Complex according to claim 3 wherein R¹⁹, R²⁰, R²¹ and R²² are each independently selected from methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert- butyl, n-pentyl, neopentyl, n-hexyl, 4-methylpentyl, n-octyl, phenyl and benzyl. i o n *? ι

7. Complex according to claim 3 wherein one of R and R is hydrogen, one of R and R²² is hydrogen, and the other is each independently selected from methyl, ethyl, n- propyl, iso-propyl, n-butyl, sec-butyl, tert. -butyl, n-pentyl, neopentyl, n-hexyl, 4- methylpentyl, n-octyl, phenyl and benzyl.

8. Complex according to claim 1 wherein R⁵ is a group having the formula -NR²⁹R³⁰ and R is a group having the formula -NR R , wherein R to R are independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl; when any two or more of R¹ to R⁴, R⁶ and R²⁹ to R³² are hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl or substituted heterohydrocarbyl, said two or more can be linked to form one or more cyclic substituents.

9. Complex according to any preceding claim wherein the transition metal M is N[II], N[III] or Ti[III].

10. Complex according to any preceding claim wherein at least one and preferably both of R⁴ and R⁶ is a hydrocarbyl group having at least two carbon atoms.

11. Complex according to claim 10 wherein R⁴ and R⁶ are each independently ethyl, isopropyl, t-butyl, phenyl or CH₂CH₂Ph.

12. Complex according to any preceding claim wherein X is selected from halide, sulphate, nitrate, thiolate, thiocarboxylate, BF₄ ^", PFβ^", hydride, hydrocarbyloxide, carboxylate, hydrocarbyl, substituted hydrocarbyl and heterohydrocarbyl, and β- diketonates.

13. Complex according to claim 12 wherein X is selected from chloride, bromide, methyl , ethyl, propyl, butyl, octyl, decyl, phenyl, benzyl, methoxide, ethoxide, isopropoxide, tosylate, triflate, formate, acetate, phenoxide and benzoate.

14. Complex according to any preceding claim which comprises 2,6-diacetylpyridinebis(2,4,6-trimethylanil)NCl₃, 2,6-diacetylpyridinebis(2,4- dimethylanil)NCl₃, 2,6-diacetylρyridinebis(2-methylanil)NCl₃, 2,6- dibenzoylpyridinebis(2,4,6-trimethylanil)NCl₃ and 2,6-diacetylpyridinebis(2,4,6- trimethylanil)TiCl₃.

15. Polymerisation catalyst comprising

(1) a complex as defined in any preceding claim and including NO[2,6-bis-(l- (phenylimino)ethyl)pyridine]X₂ where X is Cl or Br, and

(2) an activating quantity of at least one activator compound.

16. Catalyst according to claim 15 wherein the activator is selected from organoaluminium compounds, hydrocarbylboron compounds and salts of a cationic oxidising agent and a non-coordinating compatible anion.

17. Catalyst according to claim 16 wherein the activator is selected from trimethylaluminium (TMA), triethylaiuminium (TEA), tri-isobutylaluminium (TIBA), tri- n-octylaluminium, methylaluminium dichloride, ethylaluminium dichloride, dimethylaluminium chloride, diethylaluminium chloride, ethylaluminiumsesquichloride, methylaluminiumsesquichloride, and alumoxanes

18. Catalyst according to any one of claims 14 to 16, further comprising a neutral Lewis base.

19. Catalyst according to claim 18 wherein the neutral Lewis base is selected from alkenes (other than 1 -olefins) or alkynes, primary, secondary and tertiary amines, amides, phosphoramides, phosphines, phosphites, ethers, thioethers, nitriles, esters, ketones, aldehydes, carbon monoxide and carbon dioxide, sulphoxides, sulphones and boroxines.

20. Catalyst according to any one of claims 15 to 19 which is supported on a support material comprising silica, alumina, MgCl₂ or zirconia, or on a polymer or prepolymer comprising polyethylene, polypropylene, polystyrene, or poly(aminostyrene).

21. Catalyst according to any one of claims 15 to 20 which comprises more than one complex as defined in any of claims 1 to 12, or a complex as defined in any of claims 1 to 13 plus a tridentate nitrogen-containing Fe or Co complex, which is preferably 6- diacetylpyridinebis(2,4, 6-trimethyl anil)FeCl₂.

22. Catalyst according to any one of claims 15 to 20 which comprises a complex as defined in any of claims 1 to 12 plus a further catalyst suitable for the polymerisation of 1 -olefins, preferably a Ziegler-Natta catalyst systems, metallocene-based catalysts, monocyclopentadienyl- or constrained geometry based catalysts, or heat activated supported chromium oxide catalysts (eg Phillips-type catalyst).

23. Process for the polymerisation or copolymerisation of 1 -olefins, comprising contacting a monomeric olefin under polymerisation conditions with a complex or catalyst as defined in any preceding claim, including VO[2,6-bis-(l- (phenylimino)ethyl)pyridine]X₂ where X is Cl or Br.

24. Process according to claim 22 comprising the steps of : a) preparing a prepolymer-based catalyst by contacting one or more 1 -olefins with a catalyst, and b) contacting the prepolymer-based catalyst with one or more 1 -olefins, wherein the catalyst is as defined in any of claims 15 to 23.

25. Process according to claim 23 or 24 wherein the polymerisation is conducted in the presence of hydrogen as a molecular weight modifier.

26. Process according to any one of claims 22 to 24 wherein the polymerisation conditions are solution phase, slurry phase or gas phase.

27. Process according to claim 26 wherein the polymerisation is conducted under gas phase fluidised bed conditions.

28. Process according to claim 26 wherein the polymerisation is conducted in slurry phase in an autoclave or continuous loop reactor.

29. Process according to any one of claims 23 to 28 wherein the copolymerisation comprises formation of an ethylene/1-olefin/diene terpolymer in which the diene is preferably as 1,4 pentadiene, 1,5-hexadiene, cyclopentadiene or ethylene norbomadiene, and the other 1 -olefin is preferably propylene.

30. Use of a complex as defined in any of claims 1 to 14 as a catalyst for the polymerisation of 1 -olefins.