WO1990009402A1

WO1990009402A1 - A new method of preparing a catalyst component for the polymerization of olefins

Info

Publication number: WO1990009402A1
Application number: PCT/FI1990/000048
Authority: WO
Inventors: Thomas Garoff; Timo Leinonen
Original assignee: Neste Oy
Priority date: 1989-02-16
Filing date: 1990-02-15
Publication date: 1990-08-23
Also published as: CA2047712A1; FI83332C; JPH04504865A; EP0451214A1; FI890765A0; FI890765A; FI83332B

Abstract

The invention relates to a new method for preparing a supported procatalyst of a catalyst system intended for the polymerization of olefins, in which the reaction product formed from magnesium halogenide and an alcohol is treated in order to remove the alcohol and is activated with a transition metal compound and optionally an electron donor. In solutions of prior art the transition metal compound reacts with the alcohol as well as with the magnesium chloride and additionally acts as a medium for separating the by-product formed of itself and the alcohol. The problem is then that great amounts of transition metal are wasted and that said by-product is a harzardous waste that is difficult to treat. These problems have been solved in the present invention by removing the alcohol with the aid of a separate grinding-evaporation step. The grinding-evaporation step is preferably carried out by jet mills by using a temperature gradient for the gas.

Description

A new method of preparing a catalyst component for the polymerization of olefines

The invention relates to a method of preparing a supported procatalyst of a catalyst system intended for the polymeriza¬ tion of olefins, in which a particulate reaction product formed from magnesium halogenide and alcohol is treated in order to remove alcohol and is activated with a transition metal compound and optionally with an electron donor.

The so-called Ziegler-Natta catalyst system is generally used for polymerizing olefines, consisting of a so-called procata¬ lyst and a cocatalyst. The procatalyst is based on a com¬ pound of a transition metal of one of the groups IVB-VIII of the periodical system and the cocatalyst is based on an or- ganometallic compound of a metal of one of the groups IA- IIIA of the periodical system. The catalyst system usually al¬ so comprises electron donor compounds improving and modifying the catalytic properties.

When preparing heterogeneous polymerization catalysts an inert carrier compound is usually applied to improve the po¬ lymerizing activity of the procatalysts , the transition metal compound being superposed on this. Magnesium compounds such as alkoxides, hydroxides, hydroxyhalogenides and halogenides have turned out to be important carrier compunds, the latter, :„n particular magnesium chloride, having lately become the major carrier components of procatalysts.

Since magnesium compounds in their basic crystalline form are not very effectively activated by a transition metal compound, their crystalline structure has to be deformed. This is con¬ ventionally done by grinding e.g. in a ball mill. In this case the magnesium compound, such as a magnesium chloride-like mag- nesium halogenide, is ground either as such together with an electron donor remaining in it, or even together with the final catalyst components, e.g. in a ball mill during 50-120 hours at a temperature in the range of 40-70°C. As a result of such a ball mill grinding finely divided powder having typically a large specific surface is obtained, in which the crystal lattices of the particles are strongly deformed. When such a powder is activated into a procatalyst by superposing with a transition metal compound and subsequently is reduced with an organometal compound acting as a cocatalyst, a very active polymerization catalyst is obtained.

However, the usual grinding method of a magnesium compound has the drawback of consuming very much energy, of causing wear and abrasion of the device and is only usable when prepa¬ ring a catalyst by means of an onerous batch process.

A newer and more effective manner of increasing the activabi- lity of magnesium compounds with transition metal compounds is to modify them chemically. The JP patent specification 59 215 301 discloses a method for polymerizing or copolyme- rizing ethene, in which the carrier is prepared by bringing together a hot hydrocarbonaceous emulsion of magnesium chlo¬ ride, ethanol and an emulsifier, and a cool liquid of the same hydrocarbon. This yields a carrier agent with spheric partic¬ les, in which the particle diameter varies in the range of 53-105 microns. The carrier is activated by suspending it at room temperature in titanium tetrachloride, after which an electron donor is further added to the mixture. The procata¬ lyst achieved by this emulsifying solidification technique is particularly appropriate for the polymerization and copolyme- rization of ethene.

The US patent specification 4 506 027 discloses a method of preparing a procatalyst, in which firstly a solid carrier is achieved by spray drying a solution, in which the magnesium chloride is dissolved in a mixture of ethanol and methanol. The carrier containing ethanol and methanol hydroxyl thus obtained is then activated by titanium or vanadinium haloge- nides. As a result a procatalyst is obtained, which combined with an organoaluminium compound acting as a cocatalyst ser¬ ves well as a polymerization catalyst for alfa-olefines.

The FI patent application 86 2459 describes the preparation of a procatalyst by spray crystallizing a mixture of magne¬ sium dihalogenide and alcohol into a crystalline complex com¬ pound whose particles, due to the lack of alcohol evaporation, have more free hydroxyl groups than in prior methods. The procatalyst is obtained by activating said spray crystal¬ lization product with a tetravalent titanium compound.

According to US patent specification 4 071 674 a dry mag¬ nesium halogenide is suspended in hydrocarbon, after which alcohol is added dropwise. As a result addition product par¬ ticles crystallizing spontaneously from the reaction solution are formed, which, according to this reference, are pre- activated with an organic compound of a metal like alum___nium before activating with a transition metal compound.

The above chemical modification of a magnesium compound with alcohol is based on the fact that it yields a particle¬ like reaction product, which is e.g. a complex of magnesium halogenide and alcohol. The activation takes place so that the transition metal compound displaces the alcohol by reacting with it as well as is attached to the magnesium compund, whose crystal lattices are strongly deformed due to the alcohol eva¬ poration. Thus, an active procatalyst and as a by-product a reaction product of the transition metal compund and alcohol are produced.

The chemical modification of the magnesium compound with al¬ cohol and the activation with a transition metal compound are illustrated by the following formula, in which the magnesium 90 0

compound is magnesium chloride, the alcohol is ethanol and the transition metal compound is titanium tetrachloride.

MgCl₂ (c) I

C₂H₅OH

MgCl₂ x n C₂H₅OH <c>

II TiCl₄

1 MgCl₂(a). — TiCl₄ + TiCl₃.0C₂H₅ + HC1

III IV

wherein (c) means a crystalline state, (a) means an amorphous state, n means the molar ratio of C2H5OH and MgCla in complex II and m means the molar ratio of MgCla and TiCl-i in procatalyst III.

The crystalline magnesium chloride I is first reacted with ethanol, whereby the crystalline complex II is obtained. The complex II is then reacted with the titanium tetrachlori¬ de. Thus are formed procatalyst II, which comprises titanium tetrachloride on an amorphous magnesium dichloride carrier, and procatalyst residue IV, which is washed out with a great surplus of titanium tetrachloride. The procatalyst III thus obtained has an amorphous crystal structure and a high activity in olefine polymerization. The better the catalyst residue IV is washed out, the higher is the activity obtained. Although such a chemical modification with alcohol according to prior art is a more gentle and somewhat more effective man¬ ner of pretreating the magnesium compound than grinding, it has however many drawbacks. In catalyst production great tita¬ nium tetrachloride washing batches are inconvenient, since then the titanizing solution used has to be separated from the catalyst residue and purified before it can be recycled into the process. The after-treatment of the catalyst residue is very complicated since it reacts e.g. with the humidity in the air. Moroever, the melted catalyst residue easily clogs the pipe system. The required neutralization of the residue with water produces great amounts of hydrochloric acid.

The purpose of the present invention is to provide a method of preparing a supported procatalyst, which does not consume great amounts of raw material and does not produce hazardous waste that is harmful to the environment and difficult to handle. The invention also aims at a procatalyst having an applicable activity. These purposes have now been achieved by means of the new method of preparing a procatalyst, which is essentially characterized by the facts mentioned in the cha¬ racterizing part of claim 1. Thus, one has realized that al¬ cohol can be removed from the solid reaction product of alco¬ hol and magnesium halogenide without deteriorating the ac¬ tivity (by recrystallization of MgCl=>), wasting the transi¬ tion metal compound or producing hazardous waste, by subject¬ ing said reaction product to a combined grinding and evapora¬ tion operation. When the reaction product of magnesium halo¬ genide and alcohol is simultaneously ground and evaporated, the alcohol liberated during the grinding is removed and the structure of magnesium halogenide is formed without losing its activity by recrystallization. The method is most critical, since mere evaporation of alcohol does not lead to an amorphous and thus active procatalyst. The combined grinding and evaporating operation according to the invention can be carried out by grinding said reaction product in a heated and rapidly exchanging evaporating gas. For this method any efficient mill is usable, having an adj¬ ustable atmospheric temperature and/or being able to receive a hot evaporating gas. The grinding and evaporating operation is preferably carried out in a jet mill so that one or more gaz jets carry the particles of the reaction product against each other and/or one or more counter-pieces of the jet pul¬ verizer with such a force and at such a temperature that they are pulverized into finely divided amorphous carriers, from which an essential portion of the alcohol has been evaporated.

The gas used for the evaporation is inert with regard to the reaction product of magnesium halogenide and alcohol, and which stands heating to the desired evaporating temperature. For instance nitrogen is a suitable gas in this respect.

As raw materials for the reaction product of the invention such magnesium compounds and alcohols can be used that form an activating carrier compound when the material is being ground preferably by using a temperature gradient. Magnesium chloride is a preferred magnesium compund. Methanol and ad¬ vantageously ethanol can be mentioned among suitable alcohols. The reaction product of a magnesium compound such as magne¬ sium halogenide and an alcohol can be prepared by any known method. Such methods are described in the above patent specifications JP-59 215 301, US 4 506 027, FJ-86 2459 and US 4 071 674, among others. The criterion of these methods is forming a reaction product having a practicable morphology and stability. A preferred reaction product of magnesium halogenide and alco¬ hol is formed out of magnesium chloride and ethanol,^' orming together the crystalline complex MgCla x nCaHsOH, in which n is 1-6. The solidification of it into well' activated particles by crystallization is preferably accomplished so that the crystallizing product contains ethanol, which later, when being separated, leaves an amorphous and thus reactive carrier to be activated.

In the complex crystal formed by magnesium halogenide and al¬ cohol, the alcohol has a weakening effect on the crystal structure and thus also lowers the melting.point. For this reason, it is preferable to carry out the method of the pre¬ sent invention by applying a temperature gradient, in which the temperature of the evaporating gas is gradually raised as the alcohol is separated and removed from the reaction product formed by magnesium halogenide and alcohol.

In the beginning, when the alcohol concentration is high, the melting point of the reaction product is low. For this reason, a low evaporating temperature has to be applied, since other¬ wise the product melts, being crystallized during the resoli- dification, and fails to form the desired amorphous activated magnesium halogenide. If on the contrary, a relatively low evaporating temperature is applied in the beginning of the grinding, the alcohol liberated from te reaction product by the grinding is evaporated without the product melting. When a sufficient amount of alcohol has been evaporated, the melting temperature of the reaction product rises and the evaporation temperature can be raised. By raising the temperature of the evaporating gas during the grinding in this manner, the al¬ cohol can be removed substantially totally from the reaction product formed by the alcohol and the magnesium halogenide without any recrystallization disturbing the activability of the reaction product. The initial and final temperatures of the temperature gradient used in the method of the invention as well as the rate of raising the temperature depend entirely on the applied reac¬ tion products of magnesium halogenide and alcohol, their crys¬ talline form and the volatility of the alcohol under the grinding conditions. When using the above complex MgCla x n C-aHsOH as a starting material, nitrogen being the eva¬ porating gas, the preferred temperature gradient of nitrogen starts at approx. 20°C and ends at approx. 270°C. This temperature is preferably raised during approx. 2-3 hours, the complex thus being ground at a temperature that is always be¬ low its melting point. The use of such a temperature gradient ensures the removal of substantially all the alcohol from the reaction product of magnesium halogenide and alcohol.

As mentioned above, the use of a jet mill for the combined grinding and evaporating operation is preferable. A mill of this type is advantageous firstly because the carrier gas used for the grinding can also be used for evaporating the alcohol. The jet mill type generally known in this field can be used in the method, the general principles of which are described be¬ low.

The particle-like reaction product formed of magnesium haloge¬ nide and alcohol is fed into the mill e.g. by priming the particle flow by gravity from a funnel and/or by using a screw conveyor. The mixing into the gas jet before the grin¬ ding chamber can be enhanced by the ejection effect.

There is generally a fairly free choice of the shape of the mill chamber, but for practical reasons the following solu¬ tions are frequently opted for: (1) In case a counter-piece is used in the mill chamber, the gas jet containing the particles is fed through one end of the cylindrical chamber at one or more points, the jet being directed to the counter-piece or pieces.

(2) If two or more jets containing particles are made to collide, the jet feeding points are symmetrically placed in the walls of the vertically positioned cylindrical mill chamber.

(3) The jet or jets can also be fed tangentially to the wall of the mill chamber, whereby the gas flow containing particles is brought into a rotatory circulating movement which, when the chamber is vertical, can sink spirally downwards under the effect of gravity. In this case the rotation of the gas* flow can be guided and/or the grinding enhanced by means of auxi¬ liary jets co ing from the lower part and of possible guiciing and/or counter-pieces. ~*

(4) In case the particles to be ground are fed directly into the mill chamber, the gas jets, of which there are advanta¬ geously at least two, are directed approximately to the cent¬ ral part of the cylindrical mill chamber, into which the par¬ ticles to be ground are also fed by priming from a funnel or by means of a conveyor screw.

In case one or more parallel jets or counter-pieces are used, the gas flow and the ground particles are removed from behind and/or the side of the counter-piece at one or more points. In case a disc mill operating according to the spiral flow is also used, or in case the particles are fed directly into the mill chamber, the gas flow is generally removed from the centre of the chamber, at the upper part, and the ground par- tides from the upper and/or lower part. When using gas jets, to which the solid particles have been added either before the spraying into the mill chamber or directly in the mill cham¬ ber, the points of removal are fairly freely chosen, however so as to achieve an optimal grinding result.

After the mill chamber, the removed particles can still be conducted into a grading equipment, in which the articles ha¬ ving possibly remained too coarsely grained, are screened out, not being suitable for the preparation of an active catalyst. A counter-piece jet mill, a material or gas accelerated jet mill, a disc or spiral jet mill and a gas accelerated jet mill can be mentioned as examples of types of jet mills suitable for the method of the present invention.

The following figures show a number of jet mill types practicable in the method of the present invention.

Figures 1-4 show a schematic perspective of four jet mill models usable in the method of the present invention; figure 5 shows a graphical drawing of the temperature gradient used in embodiment example 3 and in the comparative examples B, C and D; figure 6 shows the evaporating equipment used in the compa¬ rative examples E and C; and figure 7 shows the evaporating equipment used in example D.

The jet mill type shown in figure 1 operates with an accelerated gas flow. The gas feeding line is provided with a heater and/or a superheater, which is not shown in the fi¬ gure. The model shown by the figure has only one venture nozzle 1. The heated and accelerated gas flow 2 is conducted to a feeding device 3 of the ejector type, where the particu- late reaction product 4 of magnesium halogenide and alcohol is sucked into the gas flow. After the ejector 3 the gas and reaction product flow is made to collide with the coutnter- piece 5, whereby the reaction product is pulverized. As a re¬ sult of the pulverization, the second component of the reac¬ tion product, the alcohol, is separated and evaporates into the accelerated and heated gas. The remaining ground solid material is removed through the opening behind the counter- piece 5 on the left in the figure.

In the jet mill of figure 2 the reaction product formed of magnesium halogenide and alcohol as well as the gas heated to the desired evaporating temperature are accelerated in the same Venturi (laval) nozzle 6. The gas and the material to be ground are first mixed in a pressurized premixing unit, which is not shown in the figure. After this the gas-mass flow is conducted into a dividing unit, which divides the current into two or more essentially equally sized flows. These flows are conducted to a respective Venturi nozzle 6 shown in the figu¬ re. In the nozzles 6, the rate of the gas material flow even exceeds the speed of sound. The nozzles 6 are directed against each other so that a colliding zone is formed between the nozzles in the actual mill chamber 7. If two nozzles are being concerned, they are mutually positioned so that the gas flows will not clog the opposite nozzle, i.e. the nozzles are not directed against each other, but in a small angle to each other. If there are three nozzles, the preferred arrangement is an 120 ° angle between the nozzles, as shown in the fi¬ gure.

In the disc and spiral jet mill of figure 3, the gas, which is heated by a heater or superheater outside the figure, is fed into the disc-shaped mill chamber 15 at two places. One gas flow is a so-called working gas flow 8, and the other j_s a so- called ejector gas flow 9 and the feeding can be arranged for instance by heating both or only one of the flows. The disc jet mill itself consists of two covers, an upper cover 10 and a lower cover 11. Between the covers there are two rings, the outer ring 12 and the inner ring 13. In the inner ring 13 through openings 14 are tangentially disposed. The gas flow is regulated so that there is an over-pressure in the ejector gas line 9 with regard to the working gas line 8. The ejector gas 9 absorbs the material fed from the ejector and feeds it further tangentially to the mill chamber 15, which is the space remaining inside the inner ring 13. The work gas feed 8 is fed in between the rings 12 and 13, wherefrom it is dis¬ charged tangentially into the mill chamber 15 through the opening 14 of the inner ring. The tangentially fed gas flow produces a strong rotatory movement in the gasmass flow in the mill chamber 15. The rotatory movement produces an annular colliding zone inside the inner ring 13 of the mill chamber 15. The flow formed of the gas and the mass is discharged from the disc jet mill through the hole 16 in its central part.

In the gas accelerated model shown in figure 4, only the gas heated or to be heated is accelerated in the Venturi nozzle 17. The material to be ground is fed into the gas jet after the acceleration. After this, the material is made to collide against itself, as in the preceding case, in the colliding zone formed between the nozzles. The material is fed into the mill chamber by the screw conveyor 18. Having entered the chamber, the material drops into the colliding zone 19 of the gas jets. Owing to the rapid gas flow, the particles accele¬ rate between the nozzle and the colliding zone. Often a rapidly rotating grading wheel 20 is also disposed at the upper part of the colliding chamber, throwing coarse material back into the chamber, but letting fine material through. The rotating gradig wheel 20 does not participate in the very grinding process.

Figure 5 shows the temperature gradient used in embodiment example 3 and the comparative examples b, c and d, in which the te eprature is linearly raised from 20°C to 270°O during 2,5 h. Such a temperature gradient is particularly suitable for the evaporating grinding of the complex MgClz x nCaHsOH.

Figure 6 shows an ordinary three-neck flask 21 including a heating mantle 22, a thermometer 23, a magnetic mixing rod 23 and an inlet 24 and an outlet 25 for the evaporating gas (nitrogen) . The removed drying gas is conducted to a cold trap 26 in order to condensate and recover ethanol. In the comparative example B, the equipment of figure 6 is used with¬ out a vacuum and in the comparative example C with a vacuum suction.

With the equipment shown in figure 7, which is used in the comparative example D, the evaporation of ethanol is to be enhanced by a fluidized bed produced by the evaporating gas. The equipment consists of a column 27, which is equipped with a surrounding heating mantle 28, a thermometre 29 as well as a supply 30 and removal 31 of drying gas. The exhaust gas is also in this case conducted to the cold trap 32 mainly in order to recover the evaporation products formed from ethanol.

Figures 8-14 show, in respective order, the X-ray diffraction spectres of the catalysts of the embodiment examples 1-3 and the comparative examples A-D.

Examples

a. Preparation of the catalysts

Unless otherwise indicated in the examples, the catalysts were prepared according to the following formula. 0.1 mole of the material treated with a jet mill or obtained by thermal treatment is weighed for the preparation of a catalyst. 0.1 mole of the comparative material MgClz x CsHs OH was also weighed for the catalyst synthesis. The weighing is done in an inert space, preferably a nitrogen ca¬ binet. The material is disposed in a c. 1 litre glass reactor in an inert space.

The reactor is closed before being removed from the nitrogen cabinet. It is equipped with a mixer, a vertical cooler and an adjustable nitrogen feeder line.

First 300 ml of heptane is added into the reactor by stirring and then 300 ml of titanium tetrachloride by stirring slowly. The addition is made at room temperature. Finally, 4.2 ml of di-isobutylphtalate is added dropwise while stirring conti¬ nuously. The temperature is slowly raised to 100 ^βC and the solution is continuously stirred. For the heating an oil bath is preferably used. When the desired temperature has been reached, the solution is kept there for one hour. Then the oil bath is removed and the stirring stopped The catalyst is al¬ lowed to settle to the reactor bottom, after which the tita¬ nium tetrachloride/heptane solution is siphoned out as care¬ fully as possible leaving essentially the catalyst in the reactor.

Then a new 300 ml batch of titanium chloride is added while stirring vigorously and the oil bath is replaced in position. The stirring is maintained contiuously. The temperature is also raised to 110 °C, at which the titanium chloride is left to reflux for one hour. After this the stirring stops and the oil bath is removed. The catalyst is allowed to settle to the reactor bottom and the unreacted titanium tetrachloride is siphoned out as carefully as possible leaving essentially only the catalyst in the reactor. 300 ml of washing heptane is added by stirring into the reac¬ tor containing unwashed catalyst. The oil bath is placed in position and the temperature of the solution is raised until the heptane is slightly refluxed at a temperature of approx. 90-100°C. After refluxing for approx. 15 minutes the stirring stops, the oil bath is removed and the catalyst is allowed to settle. Then the washing heptane is siphoned out as carefully as possible leaving essentially only catalyst in the reactor. The catalyst is washed six more times, of which the last is carried out without heating.

After the heptane washings the catalyst is dried by means of a nitrogen gas flow. The catalyst yield is determined by weig¬ hing the recovered amount of catalyst and the titanium con¬ tent of the catalyst is determined.

b. Test polymerization

In the test plymerization, a 2 1. bench reactor was used and heptane dried with a molecular screen is used as a medium, 1200 ml of which is added into the reactor. The air was remo¬ ved by making nitrogen bubble into the solution. Propylene was used as a monomer. 30-300 mg of the catalyst was used depen¬ ding on the activity, the quantity being weighed into a septum bottle. Triethyl aluminium is used as a cocatalyst, added in relation to the quantity of titanium in the catalyst so that the ratio Al/Ti is 200. An external donor D2 is added with the ratio Al/D2= 20.

The indicated amounts of catalyst, aluminium alkyle and donor are added into a feed ampoule, which is connected to the reactor. 50 ml of heptane is additionnally added into the am¬ poule in order to enhance the supply. The feeding is done by means of a gas flow. Before starting the polymerization hyd- rogen is ad¬ ded in order to provide the required hydrogen partial pressu¬ re. The polymerization itself takes place at a propylene mono¬ mer pressure of 10 bars and a temperature of 70°C and the duration is three hours. Then the polymer is filtered out from the medium and dried, after which the yield is determined.

c. Determination of the catalyst residue

In case the magnesium chloride is chemically activated by means of ethanol and titanium tetrachloride a stoichiometric amount of catalyst residue is obtained as a by-product of the reaction, consisting of the chlorine and ethoxide complex of titanium:

MgCl__ x EtOH + TiCl_* = MgCla + TiClsOEt + HC1

The amount of produced catalyst residue has been observed in the examples. The weight of the residue (TiClaOEt) was de¬ termined by weighing a residue batch obtained by dry evaporat¬ ing the residual solution of the first titanizing reaction. Pure titanium tetrachloride was evaporated by raising the temperature and making nitrogen flow through the vessels. If a totally clean titanium tetrachloride solution is concerned, the vessels are dry evaporated already at δO'-'C. If on the contrary the solution contains titanium ethoxides, these re¬ main in the vessel as a solid slag. The slag amount can be determined by weighing directly in the vessel provided that the weight of the vessel is known. The catalyst slag obtained contains, depending on the evaporation duration and the tem¬ perature, 10-20% of absorbed titanium tetrachloride. Thus, the method of determination is not applicable to the exact measu¬ ring of the amount of slag material, but the method provides an adequate conception of the occurence of slag components in relation to the amount of catalyst. d. Embodiment examples

Example 1

1.5 kg of an MgCl__ carrier was placed into a jet mill. The mill was a so-called disc or spiral jet mill. The carrier was ground during 10 h at a temperature of 20°C. After-the treatment, 0.1 mole of the carrier was taken for the catalyst synthesis. As a result, 8.7 g of catalyst was obtained, of which the Ti% was 4.4. 102.2 mg of this catalyst was ^*£aken for the test polymerization of propylene. As a result 19.8 g of polyprophene was obtained, corresponding to an activity of 0.2 kgPP/g cat. The titanizing solution was evaporated totally according to the instructions above. No catalyst residue was found in the reaction solution. The Xray diffraction of the catalyst was crystalline (figure 8).

Example 2

1.5 kg of an MgCl_2 carrier was placed into a jet mill. The jet mill was a so-called disc or spiral jet mill. The carrier was ground for 20 h at a temperature of 270°C. After the treatment, 0.1 mole of this carrier was taken for the catalyst synthesis. As a result, 5.7 g of catalyst was obtained, the Ti% of which was 4.2. 98.7 mg of this catalyst was taken for the test polymerization of propylene. As a result, 31.0 g of polypropylene was obtained, corresponding to an activity of 0. 3 kgPP/g cat. The titanizing solution was dry evaporated ac¬ cording to the above instructions. No catalyst residue was found in the reaction solution. The Xray diffraction of the catalyst was crystalline (figure 9).

Example 3

1.5 kg of MgCla x EtOH carrier was placed into a jet mill. The mill was a so-called disc or spiral jet mill. The carrier was ground for 3 h. During the operation a temperature gradient in the range of 20-270°C was applied according to figure 5. After the treatment, 0.1 mole of this carrier was taken for the catalyst synthesis. As a result, 6.2 g of the catalyst was obtained having a Ti% of 3.2. 75.3 mg of the catalyst was taken for the test polymerization of propylene. As a result 241 g of polyprophene was obtained, corresponding to an activity of 3.2 kgPP/g cat. The titanizing solution was totally evaporated according to the above inst¬ ructions. No catalyst residue was found in the reaction solu¬ tion. The X-ray diffraction of the catalyst was amorphous (figure 10) .

e. Comparative examples

Example A

0.1 mole of a MgCla x EtOH carrier was taken for the cata¬ lyst synthesis. As a result, 9.2 g of catalyst was obtained, the Ti% of which was 3,7. 52.1 mg of this catalyst was taken for the test polymerization of prophene. As a result 79 g of polypropylene was obtained, corresponding to an activity of 1.5 kgPP/g cat. The titanizing solution was evaporated totally according to the above instructions. 25 g of catalyst residue was found in the reaction solution after the evaporation. The X-ray diffraction of the catalyst was amorphous (figure 11).

Example B

150 g of a MgClz x EtOH carrier was weighed into a three neck flask. The flask was provided with stirring, thermostatic heating and nitrogen gas washing according to figure 6. The ethanol was evaporated from the carrier by using the tempera¬ ture gradient of figure 5. The ethanol was dry-evaporated evaporated from the carrier. 0.1 mole of the dry salt was ta¬ ken for the catalyst synthesis. As a result, 11.3 g of cata¬ lyst was obtained, having a Ti% of 2.4. 80.0 mg of the cata¬ lyst was taken for the test polymerization , yielding 3.2 g of polypropylene, corresponding to an activity of 0.04 kgPP/g cat. No catalyst residues were found in the titanizing solu¬ tion. The X-ray diffraction of the catalyst was crystalline (figure 12) .

Example C

150 g of MgClz x EtOH carrier was weighed into a three- neck flask. The flask was provided with stirring, thermostatic heating and nitrogen gas washing according to figure 6, as well as with a vacuum line. The ethanol was evaporated from the carrier by using vacuum and the temperature gradient of figure 5. The ethanol was totally evaporated from the carrier. 0.1 mole of the dry salt was taken for the catalyst synthesis. As a result, 10.9 g of the catalyst was obtained, having a Ti% of 2.4. 75.3 mg of the catalyst was taken for the test polyme¬ rization. No polypropylene was produced; the catalyst was not active. No catalyst residues were found in the titanizing so¬ lution. The X-ray diffraction of the catalyst was crystalline (figure 13) .

Example D

150 g of a MgClz x EtOH carrier was weighed into a fluidi- zed bed vessel. The vessel was provided with thermostatic heating and nitrogen gas washing according to figure 7. The ethanol was evaporated from the carrier by using the tempera¬ ture gradient of figure 5. The ethanol was totally evaporated from the carrier. 0.1 mole o the dry salt was taken for the catalyst synthesis. As a result, 11.0 g of the catalyst was obtained, having a Ti% of 2.5. 65.0 mg of the catalyst was taken for the test polymerization. No polypropylene was pro¬ duced, the catalyst was quite inactive. No catalyst residue was found in the titanizing solution. The X-ray diffraction of the catalyst was crystalline (figure 14).

The results of the embodiment examples 1-3 and of the compara¬ tive examples A-D are shown in the following table. It appears that the best result is obtained by grinding evaporation in a jet mill, in which the carrier-evaporating gas was heated ac¬ cording to the temperature gradient.

Table

Example Starting material Treatment Activity Catalyst method kgPP/g cat residue

1 None 2 None

None

Stoichiom. TiClaEt

B None

None

Claims

1. A method for preparing a supported procatalyst of a cata¬ lyst system intended for the polymerization of olefines, in which a particulate reaction product formed from a magnesium halogenide and an alcohol is treated in order to remove the alcohol and is activated with a transition metal compound and optionally an electron donor, characterized in that the al¬ cohol is removed by a separate grinding-evaporation step.

2. A method according to claim 1, characterized in that the separate grinding-evaporation step is carried out by grinding the reaction product in a heated and rapidly exchan¬ ged evaporating gas.

3. A method according to claim 1, characterized in that the magnesium halogenide is magnesium chloride, which is pre¬ ferably dry and anhydrous.

. A method according to any of the preceding claims, characterized in that the alcohol is an aliphatic alcohol, preferably dry ethanol and/or ethanol.

5. A method according to any of the preceding claims, characterized in that said particulate reaction product is formed by subjecting the magnesium halogenide, which has been heated to be liquid and solvated by alcohol, to an emulsion particle solidification, a spray drying, a spray crystalliza¬ tion or crystallization from a solution.

6. A method according to any of the preceding claims, characterized in that said particulate reaction product is a complex compound according to the following formula: MgCls x n CzHsOH

in which n = 1-6.

7. A method according to any of the preceding claims, characterized in that the separate grinding-evaporation step is carried out in a jet mill, the carrier gas of the jet mill serving simultaneously as an evaporating gas of the al¬ cohol liberated by the grinding.

8. A method according to any of the preceding claims, characterized in that during the grinding-evaporation step a temperature gradient is arranged for the evaporating gas so that the temperature rises but continuously stays below the rising melting temperature of the reaction product.

9. A method according to claim 8, characterized in that the reaction product is formed from magnesium dichloride and etha¬ nol, the temperature gradient starting at c. 20°C and reach¬ ing c. 270°C in about 2.5 hours, essentially all the ethanol having then been evaporated without melting of the material to be ground.

10. A method according to any of the preceding claims, characterized in that the activation by a transition metal is carried out by means of titanium tetrachloride.

11. The use of the procatalyst prepared by the method of any of claims 1-10 for the polymerization of olefines together with an organometal compound of a metal of one of the groups IA-IIIA of the periodical system serving as a cocatalyst.