GB1572170A - Grinding a transition metal compound and the use of the ground product to polymerise olefines - Google Patents

Description

(54) GRINDING A TRANSITION METAL COMPOUND AND THE USE OF THE GROUND PRODUCT TO POLYMERISE OLEFINES (71) We, IMPERIAL CHEMICAL INDUSTRIES LIMITED, Imperial Chemical House, Millbank, London SWIP 3JF, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to processes for the treatment of compounds of transition metals, and to the use of the treated compounds as one component of an olefine polymerisation catalyst.

According to the present invention, there is provided a process wherein a solid compound of a transition metal of Groups IVA to VIA of the Periodic Table, is ground with a minor proportion of at least one organic compound which is an organosilicon compound which is an organo-silane, a siloxane or a compound containing at least one Si-N bond and/or an organophosphorus compound, and simultaneously or subsequently is also contacted with a minor proportion of at least one sulphurcontaining organic compound, wherein the grinding and contacting are effected in the absence of any separately added organometallic compound which is an organometallic compound of aluminium, or of a non-transition metal of Group IIA of the Periodic Table, or a complex of an organometallic compound of a non-transition metal of Group IA or IIA of the Periodic Table and an organo-aluminium compound, and in an inert atmosphere in the absence of any quantity of oxygen-containing material, which quantity is sufficient to deleteriously affect the characteristics of the ground product as a component of an olefine polymerisation catalyst; and the at least one sulphur-containing organic compound is selected from sulphone compounds of the formula

sulphonamide compounds of the formula and

sulphide compounds of the formula

X, or each X, is, independently, a halogen atom, an alkyl, aryl, alkoxy, aryloxy, alkylthio or arylthio group, or a group --NRR', or two groups X can, together with at least two of the carbon atoms of the phenyl ring to which they are attached, form an unsaturated hydrocarbon ruing; Y, or each Y, is independently, a halogen atom, an alkyl, aryl, alkoxy, aryloxy, alkylthio, or arylthio group, or a group --NRR1, or two groups Y can, together with at least two of the carbon atoms of the phenyl ring to which they are attached, form an unsaturated hydrocarbon ring; or a group X and a group Y may be replaced by a link between the two phenyl groups attached to the SO2 group, the linkage being either direct or through a group -0-, -CH2-, -NR-, -S-, or -CO-; Z, or each Z, is, independently, a halogen atom, an alkyl, aryl, alkoxy, aryloxy, alkylthio, or arylthio group, or a group --NRR', or two groups Z can, together with at least two of the carbon atoms of the phenyl ring to which they are attached form an unsaturated hydrocarbon ring; D or each D, is, independently, a halogen atom, an alkyl, aryl, alkoxy, aryloxy, alkythio or arylthio group, or a group -NRR1; T is -S-, -0-, -NR1- or -CO-; R is a hydrogen atom or a hydrocarbyl group; R' is a hydrocarbyl group; R2 is a hydrocarbyl group or a group

n, m, p and q are each, independently, zero or an integer from 1 up to 5; x is a positive integer; and the minor proportion of the organic compound, and of the sulphur-containing organic compound, is at least 0.01, and not more than 1.00 mole, of the organic compound, or of the sulphurcontaining organic compound, for each gramme atom of the transition metal which is present in the solid compound of the transition metal.

For convenience, the term "organic compound" will hereafter be used to refer to organic compounds which are organophosphorus compounds or organo-silicon compounds, and the term "sulphur compound" will be used to refer to sulphurcontaining organic compounds having one of the defined fomulae.

In the transition metal compound, it is preferred that the metal has a valency below its maximum.The transition metal can be, for example, zirconium or vanadium, but it is particularly preferred to use a compound of titanium. It is preferred that the transition metal compound is a transition metal halide or oxyhalide (for example VOCI2), and in particular a chloride, especially titanium trichloride. The term "titanium trichloride" is used herein to refer not only to pure titanium trichloride, but also titanium trichloride compositions which incorporate other materials, in particular aluminium chloride or alkyl aluminium chlorides. Such forms of titanium trichloride are obtained by the reduction of titanium tetrachloride with aluminium metal or an organoaluminium compound.

Materials of the type, titanium trichloride/aluminium chloride, which are obtainable by the reduction of titanium tetrachloride with aluminium metal, are particularly preferred.

For convenience, the term "ground transition metal compound" will be used hereafter in referring to the "solid compound of a transition metal of Groups IVA to VIA of the Periodic Table which has been ground with a minor proportion of at least one organic compound which is an organo-phosphorus compound and/or an organo-silicon compound." If the organic compound is an organophosphorus compound, it is conveniently a compound of the formula R3P(O)y where R' is as hereinbefore defined and y is zero or one. The groups R' may be different but are conveniently all the same. The groups R' are preferably alkyl groups containing 1 up to 20 carbon atoms or aryl groups containing 6 up to 15 carbon atoms, for example tributylphosphine or triphenylphosphine.

If the organic compound is an organosilicon compound, it is either an organo-silane, a siloxane or a compound containing at least one Si-N bond, for example octamethylcyclotetrasiloxane [Si(CH3)2O]4 a polysiloxane of the formula (CH3)3Si(OSi(CH3)2)8OSi(CH3)3 hexamethyldisilazane [(CH3)3SiNHSi(CH3)3] or tetrakis(dimethylamino)silane ([(CH3)2N]4Si).

The sulphur compound can be a sulphone such as diphenylsulphone, a substituted derivative thereof or a compound such as phenoxa-thiin-10-, 10-dioxide or thioxan thene-10,10-dioxide. Other sulphur compounds include N,N-diethyl-4-phenoxy- benzenesulphonamide, N,N-diphenylbenzenesulphonamide and phenoxathiin.

The solid compound of the transition metal is ground with at least one organic compound and it is also contacted with at least one sulphur compound. the contacting may be effected by mixing the ground transition metal compound with a solution of the sulphur compound or by effecting a grinding step in which the transition metal compound is ground in the presence of the sulphur compound.

The contacting of the sulphur compound with the transition metal compound can be effected after the transition metal compound has been ground with the organic compound. However, if the solid compound of the transition metal is ground with both the organic compound and the sulphur compound, all the components may be added to the grinding apparatus before effecting grinding and then the contacting is effected simultaneously. Indeed, depending on the order in which the conponents are introduced into the grinding apparatus, the sulphur compound may contact the solid compound of the transition metal before the organic compound is added.

If the ground transition metal compound is mixed with a solution of the sulphur compound, this may be conveniently effected by heating to a temperature of at least 60"C. The mixture of the ground transition metal compound and the solution of the sulphur compound is conveniently heated at a temperature in the range from 80"C up to 1200C. The mixture is conveniently maintained at the temperature of at least 60"C for a time of from 0.5 up to 25 hours, especially from 2 up to 20 hours.

During the contacting, it is preferred to agitate the mixture.

If the solid compound of the transition metal is ground both with the organic compound and the sulphur compound, the grinding may be effected in two separate stages, during the first of which only the organic compound is present, and during the second stage, the sulphur compound is also present. If grinding is effected in two separate stages then, during the second stage of the grinding, a metal halide such as aluminium chloride or titanium tetrachloride may also be present. However, it will be appreciated that all the components, including the optional metal halide, may be ground together in a single grinding stage.

The amount of the organic compound which is ground with the transition metal compound is at least 0.01 mole, and not more than one mole, for each gramme atom of the transition metal which is present in the solid compound and is conveniently from 0.01 up to 0.50 mole, preferably from 0.05 up to 0.20 mole for each gramme atom of the transition metal which is present in the solid compound.

The amount of the sulphur compound is also at least 0.01 mole, and not more than 1.00 mole, for each gramme atom of the transition metal which is present in the solid compound and is conveniently from 0.05 up to 1.00 mole, preferably from 0.10 up to 0.50 mole for each gramme atom of the transition metal which is present in the solid compound. It is particularly preferred that the amount of the sulphur compound is at least equal to the amount of the organic compound.

If a metal halide such as titanium tetrachloride or aluminium chloride, is present during the grinding, it is preferred that the amount, in moles, of the titanium tetrachloride or aluminium chloride does not exceed the amount, in moles, of the sulphur compound and the amount of the metal halide is conveniently from 0.01 up to 0.50, particularly from 0.10 up to 0.40, mole for each gramme atom of the transition metal which is present in the solid compound.

The grinding is conveniently effected using a ball mill and it is preferred that at least a proportion of the grinding is effected in the dry state; that is in the absence of added solvent and suspending liquids. The materials to be ground can be introduced into the mill, or other grinding apparatus, either in the absence of solvents, or as a solution or suspension in a suitable inert diluent which is subsequently removed either by heating, reducing the pressure, or both. The grinding can be effected at any suitable temperature and satisfactory results may be obtained by grinding at ambient temperature (about 20--25"C) although it will be realised that higher or lower temperatures may be used if desired, for example from -10"C up to 1000C. Grinding is effected for any suitable length of time, and typically milling times of from one hour up to 100 hours or more, for example from 5 up to 72 hours, may be used. It will be appreciated that the grinding time will be dependent on the intensity of the grinding and, when using a rotating ball mill will depend on the material, size and number of balls used, and the speed of revolution of the ball mill, and is typically from 24 up to 72 hours. Other grinding techniques may be used, for example grinding in a vibrating mill, and using such other techniques, different times and temperatures of grinding may be preferred.

The ground product may be removed from the grinding apparatus as a dry solid but it may be more readily removed by adding a suitable liquid medium, in particular an inert organic liquid such as an aliphatic hydrocarbon, and washing out the ground solid as a suspension in the liquid medium. A convenient procedure is to add a suitable inert liquid medium to the mill and its contents and to continue the grinding process for a brief period, which is preferably not more than 30 minutes, and is in particular from one up to 20 minutes. The suspension thereby obtained is readily removed from the mill and residual quantities can be washed out using further quantities of the inert liquid medium. There appears to be a rapid reduction in the particle size of the solid during the wet grinding stage, and in order to avoid an undesirable particle size reduction, it is preferred to effect the wet grinding for only a relatively short period of time.

The process of the present invention is effected in an inert atmosphere, in the absence of any quantity of oxygen-containing materials such as, for example air and water vapour, which quantity is sufficient to deleteriously affect the characteristics of the ground product as a component of an olefine polymerisation catalyst.

It will be appreciated that the process of the present invention is effected in the absence of any separately added organometallic compound of non-transition metal, for example organo-aluminium compounds, which can be used as activator component of an olefine polymerisation catalyst.

The ground product, particularly if it has been obtained by milling in the presence of titanium tetrachloride, may be washed, for example with an inert aliphatic or aromatic hydrocarbon before it is used as a component of an olefine polymerisation catalyst.

The ground transition metal compound which has been contacted with the sulphur compound is suitable for use in a catalyst for the polymerisation of ethylenically unsaturated hydrocarbon monomers.

Thus, according to a further aspect of the present invention, there is provided an olefine polymerisation catalyst comprising I) a transition metal component which is the product of the process herein before defined; and 2) at least one organo-metallic com pound of aluminium, or of a non-transi tion metal of Group IIA of the Periodic Table, or a complex of an organo metallic compound of a non-transition metal of Group IA or IIA of the Periodic Table and an organo aluminium compound.

Component 2), the organo-metallic compound, can be a Grignard reagent which is substantially either free, or a compound of the type Mg(C ,Hs)2. Alternatively, component 2) can be a complex of an organo-metallic compound of a metal of Groups IA or IIA, such as, for example Mg(AlEt4)2 or a lithium aluminium tetraalkyl. It is preferred that component 2) is an organo-aluminium compound such as a bis(dialkyl aluminium oxy)alkane, a bis(dialkyl aluminium)oxide, an aluminium hydrocarbyl sulphate, an aluminium hydrocarbyl oxyhydrocarbyl or particularly an aluminium trihydrocarbyl or dihydrocarbyl aluminium hydride or halide especially aluminium triethyl or diethyl aluminium chloride. A mixture of compounds can be used if desired, for example a mixture of an aluminium trialkyl and an aluminium dialkyl halide. It may be preferred to use catalysts giving a low level of residual halogen in the polymer product, in which case component (2) is desirably a halogen-free compound, particularly an aluminium trihydrocarbyl.

In addition to any organic Lewis Base compounds present in component 1) of the catalyst, there may also be present a further quantity of an organic Lewis Base compound (component 3)). The further organic Lewis Base compound can be any such Lewis Base which is effective to alter the activity and/or stereospecificity of a Ziegler catalyst system.

The use of organic Lewis Base compounds, or complexes including organic Lewis Base compounds, in olefine polymer isation catalysts, is disclosed, inter alia in British Patent Specifications 803 198; 809 717; 880 998; 896 509; 920 118; 921954; 933236; 940 125; 966025; 969074; 971 248; 1013363; 1017977; 1049723; 1122010; 1150845; 1208815; 1234657; 1324173; 1359328; 1383207; 1423658; 1423659 and 1 423 660 and Belgian Patent Specification 693 551. However, we prefer that the further organic Lewis Base compound contains at least one atom of sulphur, nitrogen and/or phosphorus. Thus, preferred organic Lewis Base compounds, which can be used as the optional component 3) of the catalyst include "sulphur compounds" (as hereinbefore defined) such as diphenylsulphone, secondary or tertiary amines such as dibutylamine or tributylamine, diamines such as N,N,N',N'-tetramethylethylene diamine, and compounds which include both phosphorus and nitrogen atoms, such as hexamethylphosphoric triamide; N,N,N',N'-tetramethylethyl phosphoro diamidate; N,N,N',N' ,N-pentemethyl-N"- p-dimethylaminoethylphosphoric triamide; - 2 - dimethylamino - 1,3 - dimethyl - 1,3,2 diazaphospholidine - 2 - oxide and octa methylpyrophosphoramide.

In addition to, or instead of, the organic Lewis Base compound which is component 3), the catalyst may also include a susbstituted or unsubstituted polyene (Component (4)), which may be an acyclic polyene such as 3-methylheptatriene (1,4,6) or a cyclic polyene such as cydoocta- triene, cyclooctatetraene or cyclo heptatriene or derivatives of such polyenes such as the alkyl- or alkoxy-substituted polyenes; tropylium salts or complexes, tropolone, or tropone.

The proportions of the various catalyst components can be varied widely depending both on the materials used and the absolute concentrations of the com contents. However, in general for each gramme atom of the transition metal which is present in component (1) of the catalyst, there is present at least 0.05, and preferably at least 1.0 mole of component 2), but it may be desirable to use much greater quantities of component 2), for example as many as 50 mole or even more, for each gramme atom of the transition metal. In general we prefer to use more than 25, and particularly not more than 10, mole of component 2) for each gramme atom of the transition metal. The amount of the organic Lewis Base compound, which is the optional component 3), is in the range from 0.01 up to 10, preferably from 0.05 up to 5.0, and especially from 0.2 up to 2 mole for each gramme atom of the transition metal which is present in component 1) of the catalyst, and the amount, in moles, of component 3) is less than the amount, in moles, of component 2). The number of moles of any polyene which is present in the catalyst should preferably be less than the number of moles of component 2) of the catalyst. For each mole of component 2), there is conveniently present from 0.01 up to 1.0, especially 0.05 up to 0.5, for example 0.2 mole of the polyene. If the catalyst includes both components 3) and 4) the number of moles of the organic Lewis Base compound which is compound 3) and the polyene should preferably, in total, be less than the number of moles of component 2) of the catalyst. If the catalyst includes both components (3) and (4), these can conveniently be used in equimolar proportions but the relative proportions of these components may be varied to give the optimum result.

The Lewis Base which is component 3) of the catalyst is conveniently hexamethylphosphoric triamide; 2-dimethylamino-1,3- dimethyl- 1 ,3,2-diazaphospholidine-2-oxide; N,N,N,',N',N"-pentamethyl-Nt'-,B-dimethyl- aminoethyl phosphoric triamide; tetramethylethylenediamine; tributylamine or diphenylsulphone.

The catalysts of the present invention are particularly suitable for the polymerisation and copolymerisation of olefine monomers by contacting at least one olefine monomer with a catalyst of the type hereinbefore defined.

More specifically, there is provided a process for the production of a polymer or copolymer of an olefine monomer wherein at least one olefine monomer, or a mixture of at least one olefine monomer and ethylene, is contacted with an olefine polymerisation catalyst as hereinbefore defined.

Any olefine monomer, particularly monoa-olefine monomer, which is capable of being polymerised using a Ziegler catalyst may be polymerised by the process of the present invention. Thus, monomers which can be polymerised by the present process include butene-l, and 4-methylpentene-1 and particularly propylene. These olefines may be copolymerised together but we prefer to effect copolymerisation with ethylene, conveniently using a sequential polymerisation process such as described in British Patents 970 478; 970 479 and 1014944.

We have found that the process of the present invention can be used for the polymerisation of propylene to give a high yield of polymer relative to the amount of catalyst used and also a relatively low proportion of the undesirable soluble polymer.

It is well known that catalysts of the "Zeigler" type are susceptible to the effects bf impurities and the activity and stereospecificity of such catalysts can be affected in a detrimental manner by the presence of small quantities of impurities, particularly oxygen and polar compounds such as water and alcohol in the monomer and/or diluent when used. Thus, for the polymerisation of olefine monomers using Ziegler catalysts, it is known to use pure monomers and diluents. However, when using catalysts in accordance with the present invention, these can be used in smaller proportions than the conventional Ziegler type catalyst and accordingly are more susceptible to any impurities present in the system. Thus, for use with the catalyst of the present invention, it is desirable that the monomers and any diluents which are of commercial purity are subjected to a further purification procedure.

The purification treatment can be effected in more than one stage if desired.

The particular purification treatment used will be dependent on the purity of the starting materials.

Satisfactory purity can be achieved in most cases by passing the monomer (and diluent, if used) through a bed of a material which is capable of absorbing the impurities contained in the monomer or diluent, for example as described in British Patent Specifications Nos. 1111 493 and 1,226,659.

Using catalysts in accordance with the present invention, polymerisation can be carried out in the presence or absence of an inert diluent such as a suitably purified paraffinic hydrocarbon. If a diluent is not used, polymerisation can be effected in the liquid phase using excess liquid monomer as the suspension medium for catalyst and polymer product. If the monomer is used in the gaseous phase, polymerisation can be effected using any technique suitable for effecting a gas/solid reaction such as a fluidised bed reactor system or a ribbon blender type of reactor.

Polymerisation may be effected either in a batch manner or on a continuous basis.

The catalyst components may be introduced into the polymerisation vessel separately but it may be preferred, particularly if polymerisation is being effected on a continuous basis, to mix all the catalyst components togther before they are introduced into the polymerisation reactor.

The polymerisation can be effected in the presence of a chain transfer agent such as hydrogen or a zinc dialkyl, in order to control the molecular weight of the product formed. If hydrogen is used as the chain transfer agent, it is conveniently used in an amount of from 0.01 up to 5.0%, particularly from 0.10 up to 2.0% molar relative to the monomer. The amount of chain transfer agent will be dependent on the polymerisation conditions, especially the temperature, which is typically in the range from 20"C up to 100 C, preferably from 50"C up to 850C.

Using catalysts in accordance with the present invention propylene may be polymerised to give a high yield, relative to the transition metal content of the catalyst, of a polymer having a high flexural modulus.

Various aspects of the present invention will now be described with reference to the following Examples which are illustrative of the invention. In the Examples, all operations were effected under an atmosphere of nitrogen unless otherwise indicated.

Example 1.

Into a stainless steel mill of 15.2 cm in length and 7.9 cm in diameter, and fitted internally with four metal strips, were introduced 200 stainless steel balls of 12.7 mm diameter and 200 stainless steel balls of 6.35 mm diameter. The mill was sealed, evacuated to 0.2 mm of mercury, and purged with nitrogen, to give a nitrogen atmosphere in the mill.

5.86 g of diphenylsulphone (0.20 mole based on the titanium trichloride content of the Stauffer TiCI3-AA subsequently added to the mill) was added to the mill, followed by 1.0 ml of octamethylcyclotetrasiloxane (0.096 mole of siloxane repeat units relative to the titanium trichloride content of the Stauffer TiCI3-AA subsequently added to the mill). The mill was evacuated to 0.2 mm of mercury and purged with nitrogen. 26.7 g of titanium trichloride (Stauffer TICI3-AA) were then added and finally 1.47 ml of titanium tetrachloride (0.10 mole based on the titanium trichloride content of the Stauffer TiCI3-AA).

The mill was rotated at 120 rpm and water at 20"C was run over the exterior of the mill.

After milling for 24 hours, rotation of the mill was stopped, 100 ml of an inert aliphatic hydrocarbon liquid (boiling point range of about 170--180"C) was added and milling was continued for a further 5 minutes. The resulting slurry was transferred to a storage vessel and the mill was washed twice with 100 ml aliquots of the same intert hydrocarbon diluent. The washings were transferred to the storage vessel.

Example 2.

The procedure of Example 1 was repeated with the exception that a polysiloxane of the formula (CH3)3Si(OSi(CH3)2)8OSi(CH3)3 was used, in an amount of 0.082 mole of siloxane repeat units relative to the titanium trichloride content of the Stauffer TiCI3 AA, and the milling was effected in the presence of the inert hydrocarbon liquid for only 2 minutes.

Example 3 and 4.

The titanium trichloride products of Examples 1 and 2 were used to polymerise propylene.

The propylene used for the polymerisation had been purified by passing gaseous propylene in turn through a column (3 inches diameter, 3 feet length) containing 1/16 inch granules of Alcoa (alcoa is a Registered Trade Mark) Fl alumina at 5060 C, and then through a similar column containing BTS catalyst (Cupric oxide reduced to finely divided metallic copper on a magnesium oxide support) at 40--50"C condensing the issue gas and passing the liquid propylene through four columns (all 3 inches diameter; two of 3 feet in length, two of 6 feet in length) at 250C, each containing 1/16 inch pellets of Union Carbide 3A molecular sieves.

This treatment reduced the water content of the monomer from 5-10 ppm by volume to < 1 ppm by volume and the oxygen content from 1-2 ppm by volume to < 0.5 ppm by volume. The level of inert compounds (nitrogen, ethane, etc.) was unchanged at 0.3% and the level of unsaturated hydrocarbons (allene, methylacetylene etc.) was unchanged at < 1 ppm.

A polymerisation flask equipped with efficient stirrer and a water jacket was dried carefully and 1 litre of an inert hydrocarbon diluent having a boiling range of about 170--180"C was introduced. The diluent was evacuated at 700C purged with nitrogen and evacuated which treatment effectively reduced the water and oxygen contents of the diluent to below 10 ppm by weight. The diluent was then saturated with the purified propylene, containing 0.15% by volume of hydrogen, to one atmosphere pressure. 10 millimoles of diethyl aluminium chloride were introduced into the polymerisation vessel followed immediately by 1.0 millimole of tri-n-butylamine. 2 millimoles of the TiCI3 materials obtained as described in Examples 1 and 2, were then introduced. The temperature was maintained at 700C and the pressure in the reaction vessel was maintained at one atmosphere by supply of propylene containing 0.15% by volume of hydrogen.

After a period of four hours from the introduction of the TiCI3 the run was terminated with 10 ml of isopropanol and 5 ml of propylene oxide and a sample of supernatant liquid extracted for determining the concentration of soluble polymer dissolved in the polymerisation diluent. The solid was filtered and washed three times with petrol ether and dried in a vacuum oven at 120"C for an hour.

The results obtained are set out in the Table.

TABLE

Yield of I Wt of Type of Solid Polymer Diluent TiCI3 (g/rnM TiCI3) Soluble Polymer Example (a) (b) (c) 3 1 35.70 1.40

Claims (20)

**WARNING** start of CLMS field may overlap end of DESC **. maintained at 700C and the pressure in the reaction vessel was maintained at one atmosphere by supply of propylene containing 0.15% by volume of hydrogen. After a period of four hours from the introduction of the TiCI3 the run was terminated with 10 ml of isopropanol and 5 ml of propylene oxide and a sample of supernatant liquid extracted for determining the concentration of soluble polymer dissolved in the polymerisation diluent. The solid was filtered and washed three times with petrol ether and dried in a vacuum oven at 120"C for an hour. The results obtained are set out in the Table. TABLE Yield of I Wt of Type of Solid Polymer Diluent TiCI3 (g/rnM TiCI3) Soluble Polymer Example (a) (b) (c) 3 1 35.70 1.40 4 2 36.80 1.27 Notes to Table (a) I and 2 are the products of Examples 1 and 2 respectively. (b) Based on solid polymer only relative to the TiCI3 content of the catalyst. (c) % based on the total polymer (solid + soluble) formed. Example 5. Stauffer-AA was milled with tributylphosphine, diphenyl sulphone and titanium tetrachloride using a mill as described in Example 1. The milling procedure was as follows. Stauffer TiCI3-AA (20.1 grammes) was introduced into the mill under nitrogen followed by tributylphosphine in an amount of 0.15 mole based on the titanium trichloride content of the Stauffer-AA whilst the mill was being rotated. The mill was rotated at 120 rpm and water at 180C was run over the outside of the mill. After milling for 16 hours, the spray of water was turned off and rotation of the mill was stopped. To the mill was then added diphenylsulphone (0.05 mole based on the titanium trichloride content of the Stauffer AA) followed by titanium tetrachloride (0.20 mole based on the titanium trichloride content of the Stauffer-AA). The sulphone and the titanium tetrachloride were added under an inert atmosphere of dry nitrogen. The titanium tetrachloride was added slowly from a syringe whilst the mill was rotating and distributed as evenly as possible within the mill. Milling was continued at 120 rpm, water at 180C being run over the outside of the mill. After 24 hours, 100 ml of an inert aliphatic hydrocarbon liquid, as described in Example 1, was added and milling was continued for a further 5 minutes. The resulting slurry was transferred to a storage vessel and the mill was washed three times with 100 ml aliquots of the same inert hydrocarbon diluent. The washings were transferred to the storage vessel. Our copending Application 17491/76 (Serial No. 1561841) describes and claims a process of grinding a titanium trihalide in the presence of an alkyl phosphorus compound and a titanium tetrahalide. WHAT WE CLAIM IS:

1. A process wherein a solid compound of a transition metal of Groups IVA to VIA of the Periodic Table, is ground with a minor proportion of at least one organic compound which is an organo-silicon compound which is an organo-silane, a siloxane or a compound containing at least one Si-N bond and/or an organophosphorus compound, and simultaneously or subsequently is also contacted with a minor proportion of at least one sulphurcontaining organic compound, wherein the grinding and contacting are effected in the absence of any separately added organometallic compound which is an organometallic compound of aluminium, or of a non-transition metal of Group IIA of the

Periodic Table, or a complex of an organometallic of a non-transition metal of Group IA or IIA of the Periodic Table and an organo-aluminium compound, and in an inert atmosphere in the absence of any quantity of oxygen-containing material, which quantity is sufficient to deleteriously affect the characteristics of the ground product as a component of an olefine poly merisation catalyst; and the at least one sulphur-containing organic compound is selected from sulphone compounds of the formula

sulphonamide compounds of the formula

and sulphide compounds of the formula

X, or each X, is, independently, a halogen atom, an alkyl, aryl, alkoxy, aryloxy, alkylthio or arylthio group, or a group --NRR', or two groups X can, together with at least two of the carbon atoms of the phenyl ring to which they are attached, form an unsaturated hydrocarbon ring; Y, or each Y, is independently, a halogen atom, an alkyl, aryl, alkoxy, aryloxy, alkylthio, or arylthio group, or a group ERR1, or two groups Y can, together with at least two of the carbon atoms of the phenyl ring to which they are attached, form an unsaturated hydrocarbon ring; or a group X and a group Y may be replaced by a link between the two phenyl groups attached to the SO2 group, the linkage being either direct or through a group -0-, -CH2-, -NR-, -S-, or -CO- Z, or each Z, is, independently, a halogen atom, an alkyl, aryl, alkoxy, aryloxy, alkylthio, or arylthio group, or a group -NRR1, or two groups Z can, together with at least two of the carbon atoms of the phenyl ring to which they are attached form an unsaturated hydrocarbon ring; D or each D, is, independently, a halogen atom, an alkyl, aryl, alkoxy, aryloxy, alkythio or arylthio group, or a group -NRR1; T is -S-, -0-, -NR1- or -CO-; R is a hydrogen atom or a hydrocarbyl group; R' is a hydrocarbyl group; R2 is a hydrocarbyl group or a group

n, m, p and q are each, independently, zero or an integer from 1 up to 5; x is a positive integer; and the minor proportion of the organic compound, and of the sulphur-containing organic compound, is at least 0.01, and not more than 1.00 mole, of the organic compound, or of the sulphur containing organic compound, for each gramme atom of the transition metal which is present in the solid compound of the transition metal.

2. A process as claimed in claim 1 wherein in the transition metal compound the metal has a valency below its maximum.

3. A process as claimed in claim 1 or claim 2 wherein the transition metal compound is a titanium trichloridecontaining material.

4. A process as claimed in any one of claims 1 to 3 wherein the organophosphorus compound is a compound of the formula R13P(O)y where y is zero or one.

5. A process as claimed in any one of claims 1 to 4 wherein the sulphur-containing organic compound is diphenylsulphone, phenoxathiin-10,10-dioxide, thioxanthene 10,10-dioxide, N,N-diethyl-4-phenoxybenzenesulphonamide, N,N-diphenylbenzenesulphonamide or phenoxathiin.

6. A process as claimed in any one of claims 1 to 5 wherein the transition metal compound is ground with the at least one organic compound and the ground product is mixed with a solution of the sulphur containing organic compound and the mixture is heated to a temperature of at least 60"C.

7. A process as claimed in any one of claims 1 to 5 wherein the transition metal compound is ground in the presence of the sulphurcontaining organic compound.

8. A process as claimed in claim 7 wherein aluminium chloride or titanium tetrachloride are present during the grinding with the sulphur-containing organic compound.

9. A process as claimed in claim 7 or claim 8 wherein all the components are ground together in a single grinding stage.

10. A process as claimed in any one of claims 7 to 9 wherein the grinding is effected using a ball mill and at least a proportion of the grinding is effected in the dry state.

Il. A process as claimed in any one of claims 1 to 10 wherein the transition metal compound is ground with the at least one organic compound, contacted with the sulphur-containing organic compound and the product obtained is washed with an inert aliphatic or aromatic hydrocarbon.

12. A process as claimed in claim I and substantially as hereinbefore described with particular reference to any one of Examples 1, 2 or 5.

13. A transition metal compound which has been subjected to the process of any one of claims 1 to 12.

14. An olefine polymerisation catalyst comprising 1) a transition metal compound as claimed in claim 13; and 2) at least one organo-metallic compound of aluminium, or of a non-transition metal of Group IIA of the Periodic Table, or a complex of an organo metallic compound or a non-transition metal of Group IA or IIA of the Periodic Table and an organo aluminium product.

15. An olefine polymerisation catalyst as claimed in claim 14 in which, in addition to any organic Lewis Base compounds present incomponent I)of the catalyst, there is also present 3) a further quantity of an organic Lewis Base compound.

16. An olefine polymerisation catalyst as claimed in claim 14 or claim 15 which also includes 4) a substituted or unsubstituted polyene which is 3-methylheptatriene (1,4,6); cyclooctatetraene; cyclooctatriene; cycloheptatriene; an alkyl- or alkoxy substituted derivative of cyclo octatetriene, cyclooctatriene or cyclo heptatriene; a tropylium salt; a tropylium complex, tropolene or tropene.

17. An olefine polymerisation catalyst as claimed in claim 14 and substantially as hereinbefore described with particular reference to either Example 3 or Example 4.

18. A process for the production of a polymer or copolymer of an olefine monomer wherein at least one olefine monomer, or a mixture of at least one olefine monomer and ethylene, is contacted with an olefine polymerisation catalyst as claimed in any one of claims 14 to 17.

19. A process for the production of a polymer or copolymer of an olefine monomer which process is as claimed in claim 18 and substantially as hereinbefore described with particular reference to either Example 3 or Example 4.

20. An olefine polymer or copolymer whenever obtained by the process of either claim 18 or claim 19.

Reference has been directed in pursuance of section 9, subsection (1) of the Patents Act 1949 to Patent Nos. 1,479,652 and 1,495,031.