Carrier for catalysts, a method of manufacturing a gel - predecessor of the carrier for catalysts, method of preparing carrier for catalysts, catalyst for polymerization of olefins and polymerization of olefins by using a catalyst

 

(57) Abstract:

Proposed: the media for katalizatorov containing at least two components selected from silicon dioxide, aluminum oxide and aluminum phosphate having a specific surface area of from 100 to 800 m2/g, a crystallization temperature higher than or equal to 700oWith, pore volume from 1.5 to 4 cm3/g, specific surface area (UE) and pore volume (VP) corresponding to the relation: yn (OP x 564 - 358); the method for manufacturing the specified media, which mix the alcohol, water, an alcoholate of silicon and acid under such conditions that avoid gelation or precipitation of silicon dioxide, is added to the mixture acidic solution of aluminum compounds and/or solution of a phosphate ion source, add a gelling agent selected gel, which is subjected to washing with water and then the organic liquid, and then dried gel to obtain a powder and calcined powder. Polymerization of olefins in the presence of a catalyst containing chromium on a carrier, as described above. The resulting catalyst has high catalytic activity, a small induction period and a good sensitivity to hydrogen. In addition, this catalyst allows to obtain olefins having raspb. f-crystals, 4 tab., 1 Il.

The invention relates to a carrier for catalysts containing at least two components selected from silicon dioxide, aluminum oxide and aluminum phosphate, in particular, consists of three components, the carrier comprising silica, alumina and aluminum phosphate. The invention relates also to a method for manufacturing a gel precursor such a carrier containing silicon dioxide, and to a method of manufacturing a carrier according to the set of the gel precursor. In addition, it relates to catalysts for the polymerization of olefins containing chromium in the medium, and to the use of these catalysts in the polymerization of olefins.

The carriers formed by mixtures of oxides, are already known. For example, in the application for the European patent EP-A-283815 describe compositions containing aluminum oxide and silicon dioxide, suitable for processing of liquid hydrocarbons. In the application for French patent FR-A-2 315 997 describe media containing aluminum oxide and aluminum phosphate, suitable for the conversion of hydrocarbons.

U.S. patent 4 758 544 (CHEVRON RESEARCH COMPANY) describes a carrier for catalysts consisting of aluminum oxide, aluminum phosphate and dook is 1.5 cm3/g, suitable for hydrogencitrate oils.

In U.S. patent 3 342 750 (ESSO) disclose the preparation of carriers for catalysts containing aluminum phosphate and silicon dioxide, the specific surface area of which is equal to, for example, 403 m2/g and the pore volume is 0.77 cm3/,

In example 1A of the patent application in the UK AND-2 090158 (PHILLIPS PETROLEUM COMPANY) describe the method of preparation of a carrier for catalysts consisting of silica and aluminum phosphate, which receive a solution containing isopropanol, water, phosphoric acid, ethylate silicon and sulfuric acid, is added to the solution of aluminum nitrate, phosphoramide acid and chromium nitrate, and put the ammonium hydroxide to make the co-gelation.

These known carriers have an increased degree of heterogeneity and crystallize very quickly from the moment when they are subjected to annealing at temperatures above 700oC. on the other hand, these carriers do not combine at the same time an increased specific surface area with a high pore volume. From this it follows that these known devices are not allow to produce catalysts based on chromium for the polymerization of olefins, which odnovremenno to hydrogen. In addition, they do not allow to obtain polyolefins having a distribution of molecular weights, adjustable between average-wide distribution and a very wide distribution for this indicator fluidity, and they usually cause significant formation of oligomers.

The invention eliminates these disadvantages by providing a new medium with homogeneous and amorphous structure, which is resistant to crystallization, which has simultaneously increased pore volume and high specific surface area, and the use of which as a carrier for a catalyst based on chromium in the polymerization of olefins, the catalyst possesses a combination of the following advantages:

- increased catalytic activity even in the absence of socializaton;

a small induction period of the polymerization, even insignificant;

good sensitivity to hydrogen;

this catalyst allows to obtain polyolefins having:

the distribution of molecular weights, modulated between srednechirchik distribution and a very wide distribution for a given flow index, and

a small fraction of oligomers.

Accordingly, the invention relates to a carrier for katalysatoren; according to the invention, the carrier has a specific surface area of from 100 to 800 m2/g, a crystallization temperature above or equal to 700oC, and a pore volume of from 1.5 to 4 cm3/g, and specific surface area (UE) and pore volume (VP) correspond to the following relation:

Pack < (OP 564 - 358),

in which

UE and es denote, respectively, the numerical values of the specific surface, expressed in m2/g, and pore volume, expressed in cm3/,

According to the invention, the specific surface (UE) of the carrier measured by the volumetric method of analysis BET British standards BS 4359/1 (1984); pore volume (VP) is the sum of the pore volume formed by pores with a radius less than or equal to 75 as measured by the method of penetration of nitrogen (BET) by volumetric method of analysis described in the British standards BS 4359/1 (1984), and pore volume, measured by a method of mercury penetration using porosimetry type PORO 2000, manufactured in the sale of the company CARLO ERBA CO., according to Belgian standards NBN B 05-202 (1976).

According to the invention the crystallization temperature of the medium determined by exposing the sample carrier heat treatment at different temperatures (500oC, 700oC, 800oC, 950oC, 1050oC), and exploring then, after each heat treatment, this treatment is Italy binary type, containing silicon dioxide (A) and aluminum phosphate (B), mainly in molar percent of (A) : (B) (10 - 95) : (90 - 5).

According to another variant of the invention, which is preferred, the media is the media triples containing silicon dioxide (X), aluminum oxide (Y) and aluminum phosphate (Z), mainly in molar percent (X) : (Y) : (Z) (10 - 95) : (1 - 80) : (1 - 85).

Another variant of the invention, especially preferred, the medium contains, in addition, at least two components selected from silicon dioxide, aluminum oxide and aluminum phosphate, titanium, usually in the form of titanium dioxide. The amount of titanium present in the media according to the invention, expressed in molar percent of TiO2usually at least equal to 0.1 mol.%, mainly 0,5 mol. %; the most common are the values of at least 1 mol.%. The amount of titanium, expressed in molar percent of TiO2more often than not exceeds 40 mol.%, particularly 20 mol.%, recommend a value of at most 15 mol.%.

The media according to the invention is generally present in the powdered state, the particles of which have a diameter of from 20 to 200 microns.

The media according to the invention is usually apparent specific weight above or equal the . The apparent specific gravity measure of freedom of expiration on the following principle: in a cylindrical vessel with a capacity of 50 cm3sprinkle powdered sample media, avoiding clumping, through the funnel, the lower edge of which is 200 mm above the upper edge of the vessel. Then weigh the vessel, filled with powder, subtract the tare and divide the result (expressed in g), 50.

In addition to silicon dioxide, aluminium oxide and/or aluminum phosphate, and/or, if needed, titanium, media according to the invention may if necessary contain additional substances. For example, we can talk about insignificant quantities of elements of groups 1A and 11A of the periodic table of elements periodic or on such metals as iron, but these elements must be present in limited quantities, without affecting the properties inherent to the media.

The invention relates also to a method for manufacturing a gel precursor of the carrier according to the invention, as described above, which is mixed in the first stage, alcohol, water, an alcoholate of silicon and acid in such quantities that the molar ratio of water to silicon was from 2 to 50, add to obtained in this way hydrolysis cf the phase gelling agent; according to the invention in the first stage is carried out at acidic pH first mixing water, acid, silicon alcoholate and alcohol, and the temperature during mixing is less than or equal 30oC, and then maturation obtained in this way hydrolytic environment at a temperature at least equal to the 20oC and below the boiling point of the medium, thus at least part of the groups alkoxyl alcoholate of silicon are replaced by hydroxyl groups, without gelation or precipitation of silicon dioxide.

In the method according to the invention an alcoholate of silicon dioxide used in the first stage, can be any compound in which silicon is associated with at least one group of alkoxyl as aromatic or aliphatic, linear, branched or cyclic chain, saturated or unsaturated, unsubstituted or substituted group alkoxyl. Group alkoxyl usually contain from 1 to 20 carbon atoms. Especially recommend the alcoholate of silicon containing group alkoxyl aliphatic type; prefer alcoholate of silicon containing group alkoxyl aliphatic, unsubstituted type, such as, for example, the group of methyl, ethyl, n-propyl, ISO-propyl, n-butyl and ISO-butyl. The alcoholate of silicon, CCITT Tetra-ethylate silicon. Needless to say, you can apply multiple alcoholate of silicon on the first stage of the method according to the invention.

In the method according to the invention, the alcohol used in the first stage, dissolves the silicon alcoholate. In principle, can fit any alcohol, which dissolves the silicon alcoholate and which can be mixed with water. So, you can apply an alcohol, a hydrocarbon group which may be saturated, unsaturated, aromatic or aliphatic, straight or cyclic, unsubstituted or substituted partially or completely. Preferred aliphatic alcohols with a linear chain. As examples, ethanol, isopropanol and methanol. Especially preferred is ethanol. Needless to say, you can apply multiple spirits at the first stage of the method according to the invention. Mostly use alcohol, a hydrocarbon group which corresponds to a group of alkoxyl used alcoholate of silicon.

The amount of alcohol used in the first stage of the method according to the invention, should be sufficient to ensure complete dissolution of the silicon alcoholate, and it depends in this case on the silicon alcoholate and alcohol, which are selected from the solubility of alcohol is to use the number, greatly exceeding the required minimum number, since a large excess causes unnecessary dilution of the mixture leaving the first stage, which should be avoided.

The first stage of the method according to the invention is intended

(a) partial hydrolysis of the alcoholate of silicon in the presence of water and

(b) a partial condensation of the hydrolyzed silicon alcoholate, according to the following reactions

(a) Si(O-R)4+ x H2O ---> Si(OH)x(O-R)4-x+x R-OH

(b) 2Si(OH)x(O-R)4-x---> O-[Si(OH)x-1(O-R)4-x]2+ H2O

or

2Si(OH)x(O-R)4-x---> [Si(OH)x(O-R)3-x] -O- [Si(OH)x-1(O-R)4-x] + R-OH,

in which R represents a hydrocarbon radical, which may be aromatic or aliphatic, saturated or unsaturated, linear, branched or cyclic chain, which can if necessary be different in the four groups (O-R), and x represents the number above 0 and below 4, mainly from 0.1 to 3.9. In the first stage, use the amount of water that the molar ratio between the amount of water and the amount used alcoholate of silicon ranges from 2 to 50. Mostly this molar ratio is from 2 to 20, particularly the alcoholate of silicon" refers to compounds O-[Si(OH)x-1(O-R)4-x]2and [Si(OH)x(O-R)3-x]-O-[Si(OH)x-1(O-R)4-x] defined above.

One of the main features of the method according to the invention is the combination of such working conditions at the first stage of hydrolysis, which avoid any precipitation or gelation of silica hydrolysis in the environment. To this end, the mixing in the first stage is carried out in certain conditions regarding pH and temperature of the hydrolysis medium, the molar ratio of the quantities of water and applied alcoholate of silicon and method of mixing the reagents. Under hydrolytic environment means the environment obtained after mixing water, acid, silicon alcoholate and alcohol. To this end, the first stage of the method according to the invention the pH of the hydrolysis medium has an acidic value. Usually pH below 3, preferably from 0.5 to 2.5, for example, approximately 1. The acid used in the first stage, may be mineral or organic. It is advantageous to choose from acids, mixed with water, in which the anion is easily removed during subsequent processing of the precursor gel. For example, can we talk about hydrochloric, nitric, phosphoric or sulfuric acid. Mostly use hydrochloric or nitric acid. Particularly well podhodite. The amount of acid should be sufficient to maintain an acidic pH during the entire period of the first stage. In this case, the amount of acid depends on the degree of acidity of the used acid and other reagents and the temperature at which carry out the first stage. Disadvantageous to use a too high amount of acid in order to avoid the need for removal of excess acid or its derivatives, at a subsequent stage of processing of the gel precursor.

In the first stage of the method according to the invention, it is important to mix the reagents in a controlled way to avoid precipitation or gelation of the silica and to avoid heating the mixture. To this end, the reagents can be mixed by any known method, and it is necessary that the temperature during mixing of the reagents was the most equal to 30oC and to avoid any precipitation or gelation of the silica. Mainly mixing carried out by mixing the previously prepared mixture containing water and acid, with a pre-prepared mixture containing the silicon alcoholate and alcohol. This can be done by adding a previously prepared mixture of water and acid artelino prepared mixture of alcohol and alcoholate to a previously prepared mixture of water and acid. Good results are obtained by adding one of the pre-prepared mixtures drops into another pre-prepared mixture of the supported under stirring. Particularly satisfactory results are obtained by adding a previously prepared mixture of water and acid, drop by drop and under stirring, to a previously prepared mixture of alcohol and alcoholate of silicon. In the first stage of the method according to the invention maintain the temperature during mixing of the reactants below the 30oC, mostly below the 20oC, usually around 10oC; recommended temperature above 0oC; then hydrolysis medium is subjected to maturation at a temperature at least equal to the 20oC and below the boiling temperature environment, for example, from 30 to 100oC; the most common are the temperature from 40 to 80oC, the recommended temperature from 50 to 70oC. Mainly maturation hydrolysis medium is carried out at a temperature above the mixing of the reactants.

In the first stage of the method according to the invention when ripe, hydrolysis occurs and progressive condensation of the silicon alcoholate according to the reactions mentioned above. All other conditions remain the same, the degree of hydroly is about to be sufficient, that was such a hydrolysis reaction, which is described above; however, it should be less than the time required to effect the gelation or precipitation of silicon dioxide. The optimal time of ripening depends on the pH of the hydrolysis medium, the nature of the reagents present in the hydrolysis medium, and temperature, and may vary from several minutes to several tens hours. Usually this time does not exceed 24 hours. Mostly time is from 0.5 to 3 hours.

In a particularly advantageous embodiment of the method according to the invention is used, in addition, in the first stage, the titanium alcoholate. The titanium alcoholate may be, for example, a compound in which the titanium is associated with at least one alkoxy group, as an aromatic or aliphatic, straight, branched or cyclic, saturated or unsaturated, unsubstituted or substituted group alkoxyl. Group alkoxyl usually contain from 1 to 2 carbon atoms. The titanium alcoholate is predominantly soluble in the hydrolysis medium. Particularly suitable titanium acetylacetonate. Needless to say, you can apply multiple alcoholate of titanium on the first stage of the method according to the invention. The titanium alcoholate in case you have the of Ogosta titanium, used in this embodiment, typically such that the titanium is present in the precursor gel in a concentration that varies from 0.05 to 20 wt.%, mainly from 0.1 to 15 weight. %, especially from 0.5 to 10 wt.% titanium calculated on the total weight of the solid fraction of the precursor gel.

In this embodiment, the titanium alcoholate can be applied at any time in the first stage. The alcoholate of titanium can be added, for example, to the pre-mixture containing water and acid, or pre-mixtures containing silicon alcoholate and alcohol. Alternatively, the titanium alcoholate can be added to the hydrolysis medium obtained after mixing water, acid, silicon alcoholate and alcohol, before puberty, during or after puberty. Good results were obtained when adding titanium alcoholate during maturation.

Recommended to add the titanium alcoholate after the first part of maturation, which is predominantly from 40 to 60%, for example, about 50% of the total time of ripening; the second part is carried out after the joining of titanium alcoholate.

This implementation is particularly advantageous when you want to include titanium in the gel precursor in the appreciation which I education in the subsequent stage of agglomerates dioxide crystalline titanium in the form of anatase or rutile".

The connection of the aluminum used in the second stage of the method according to the invention may be any compound of aluminum, which is soluble in the acidic solution used in the second stage, and which is capable of gelation under the action of the gelling agent. Especially recommended inorganic salts of aluminum and aluminum alcoholate. From ALCOHOLATES aluminum used is usually such that the aluminum associated with at least one group of alkoxyl. Among the aluminum alcoholate is especially recommended such that contain aliphatic group; prefer the aluminum alcoholate containing aliphatic, with the direct aim, saturated, unsubstituted groups such as the group of methyl, ethyl, n-propyl, ISO-propyl, n-butyl and ISO-butyl. Mostly use the alcoholate of aluminum, whose group alkoxyl contain from 1 to 20 carbon atoms.

Especially suitable alcoholate of aluminum, in which a group of alkoxide is used alcoholate of silicon.

Satisfactory results are obtained with inorganic salts of aluminum. Among the inorganic salts of aluminum are particularly preferred aluminum nitrate and aluminum chloride.

In the method according to the invention, the phosphate ion source is any compound soluble in the solution used in the second stage, and capable of forming therein phosphate ions. Especially recommended inorganic salts of phosphates [e.g., monopotassium phosphate calcium formula CaH4(PO4)2secondary acid phosphate of the formula Na2HPO4and tricalcium phosphate of the formula Ca3(PO4)2], phosphated of afrosai [for example, ethylphosphate formula (C2H5)3PO4] and phosphoric acid. Mostly use phosphoric acid.

The acidic solution of the aluminium compound and the solution of the phosphate ion source used in the second stage of the method according to the invention, it is possible to prepare any appropriate known method, and they are mostly mixed with the mixture obtained in the first stage of the method according to the invention.

In an advantageous embodiment, the Oia, to apply for the second stage of the method according to the invention only one solution, acidic, containing both a compound of aluminum and a source of phosphate ions.

The first form of implementation of this variant of the method according to the invention, when the acidic solution contains only the connection of aluminum and contains no phosphate ion source, is to obtain an acidic solution, typically by dissolving aluminum compounds in water and/or alcohol, sufficient to assure complete dissolution, and add the acid in a quantity sufficient to avoid the formation of aluminium hydroxide, which immediately precipitates and does not participate more in the education of the precursor gel. To dissolve the aluminum compounds used mainly water. Actually, it is unprofitable to use the amount of solvent (water or alcohol), exceeding the required minimum amount as the excess of solvent is required to remove in post-processing (drying) of the gel. Apply the acid can be selected from acids used in the first stage of the method according to the invention.

When the second form of implementation of this variant of the method according to the invention, when the acidic solution contains t is Yaya source of phosphate ions in water and/or alcohol, sufficient and mostly without excessive for the groups shown above. In this second embodiment, the source of phosphate ions gives the acidic nature of the solution so that there is no need to add to the solution more acid.

When the third form of implementation of this variant of the method according to the invention, which is preferred, the solution contains a compound of aluminum and a source of phosphate ions and the acidic solution obtained by dissolution of the aluminium compound and the phosphate ion source in any order in the amount of water and/or alcohol, sufficient, but without excessive for the groups shown above. In this preferred embodiment may be unnecessary adding acid, provided that the source of phosphate ions gives the solution a sufficient acidity to avoid the formation of aluminium hydroxide.

Needless to say, can be applied simultaneously in the second stage, several compounds of aluminum and/or multiple ion sources of phosphates.

In the second stage of the method according to the invention by mixing the acidic solution of aluminum compounds and solution ion source of phosphate to the mixture obtained in the first stage can be, for example, the implementation of the(acidic solution of aluminum compounds and a solution of phosphate ion source). Alternatively, a mixture of the two solutions can be added to the mixture coming from the first stage; in this case prefer to work slowly to avoid heating the mixture, introducing the mixture of the two solutions, drop by drop, on Wednesday, with vigorous stirring; the environment thermostatically at a temperature below 30oC, usually lower than or equal to 20oC, for example, between 0 and 10oC during the whole period of additives.

Gelling agent used in the third stage of the method according to the invention is any compound capable of causing a co-gelation of the reagents used for the first and second stage (hydrolyzed and condensed alcoholate of silicon extending from the first stage and defined above, a compound of aluminum and/or source of phosphate ions and, if necessary, the titanium alcoholate) in the form of a mixed oxide of silicon and aluminum and/or phosphorus and, if necessary, titanium. As an example, a gelling agent can be called ethylene oxide, ammonium carbonate and ammonium hydroxide. Mostly use an aqueous solution of ammonium hydroxide.

The amount of gelling agent used in the third stage, mostly sufficient for about the about above, aluminum compounds and phosphate compounds present in the environment co-gelation. Under the environment of globalzone mean reaction mixture during gelation at the third stage of the way. Environment co-gelation includes in this case the environment is obtained at the output of the second stage of the method according to the invention (containing condensed and hydrolyzed alcoholate of silicon, a compound of aluminum and/or source of phosphate ions) and a gelling agent. The number used gelling agent predominantly enough to provide full co-gelation of the total weight of the condensed and hydrolyzed alcoholate of silicon, aluminum compounds and a source of phosphate ions; it is mostly a little higher enough.

At the third stage of the method according to the invention the pH of the environment co-gelation generally higher than or equal to 5, usually higher than or equal to 6; it is usually below 11, recommended values below 10. Mainly maintain pH constant at a value of from 6 to 10, for example, 8, during the whole time of gelation. The constancy of the pH-value you can provide any appropriate known method, for example, using a buffer solution, innertype or periodically, supply connection, changing the pH in the environment co-gelation. Used mainly vessel containing a gelling agent, which is injected separately and controlled way mixture leaving the second stage, and the connection controller pH. As a connection-pH-regulator, you can use any acidic or basic compound, inert relative to the reactants during gelation.

At the third stage of the method according to the invention may be advantageous, depending on the target properties of the gel precursor, thermostatically environment co-gelation at a temperature below or equal to 30oC, mainly at a temperature of from 0 to 20oC.

In a particularly advantageous first embodiment of the method according to the invention can, moreover, be included in the gel precursor is a transition metal selected from elements of groups IVB and VB of the periodic system of elements, such as zirconium and vanadium, or an element of group IIIA of the periodic system of elements other than aluminum, such as boron. To this end add inorganic or organic salt or alcoholate of one of these elements to the mixture obtained in the first or in the second stage of the method according to the invention, before Oswestry acid or prior to the mixture of alcohol and silicon alcoholate, used in the first stage of the method according to the invention.

In the second embodiment of the method according to the invention, which is preferred, is subjected to gel coming out of the third stage of aging. The last exercise in an environment aging, which may be the environment co-gelation, taken from the third stage, if necessary under stirring. You can add to it inert compound that alters the pH of the medium aging, for example, the primary connection. Alternatively, the gel is first separated from the environment co-gelation, for example, by centrifugation and then suspended in such an inert liquid, such as water or alcohol, to carry out aging. This option has the advantage to remove part of ionic impurities adsorbed in the gel formed from the reagents used during the manufacture of the gel.

Aging is intended to extend the co-gelation and change specific surface area and pore volume. It is carried out usually at a temperature which may vary from room temperature to the boiling temperature environment aging. Mainly work at approximately the 20oC. aging Time depends on the temperature and the properties that are required from the nose is tens of hours. The best outputs receive over time at least one hour. Taking into account economic considerations, it is unprofitable to prolong the aging above 48 hours.

Aging is carried out usually at a pH higher than or equal to 6, mostly from 8 to 10.

The method according to the invention allows to prepare the gel precursor carriers for catalysts containing silicon, aluminum and/or phosphorus in a wide range of concentrations. In fact, the method according to the invention allows the passage of all the triple a chart of the compositions of mixtures of silicon dioxide, aluminum oxide and aluminum phosphate. The drawing shows this phase diagram. The method according to the invention proves to be particularly successful for the manufacture of gels, dry fraction which has its own structure, located in the shaded part of the specified three-phase diagram. The method according to the invention can also be incorporated into the gel precursor is a transition metal or an element, such as boron.

The method according to the invention allows to prepare the gels, which are very homogeneous dispersion of the components and which can become carriers for catalysts having a combination of such specific surface area, such pore volume, and so the treatment in this case refers to a method for preparing a carrier for catalysts, which prepare the gel precursor by means of the method according to the invention, which is described above, washing the gel with water and then the organic acid, then dried his distillation to obtain a powder and calcined powder.

In the preparation method of the carrier according to the invention is subjected to gel washing, first with water and then the organic liquid.

Water rinse is usually suspendirovanie gel in water, taken in an amount sufficient to remove at least part of the impurities contained in the gel, and then removing at least part of this amount of water to any appropriate known method, for example, by centrifugation or filtration. Perform primarily centrifugation, given the rapidity of this method. Needless to say, you can repeat the washing with water several times. The temperature at which carry out this washing has little effect on the leaching efficiency and can in this case be varied within a broad range. Work mainly at room temperature.

Then subjected to gel, rinsed with water, washing with an organic liquid, for example, dispersive gel in this organic liquid at cantorian gel. The selected organic liquid is at least partially miscible with the water and be relatively inert gel, but is able to moisten the gel. It is mostly the evaporation temperature below 120oC. Usually below 100oC, for example, from 70 to 90oC. the Organic liquid used in the washing, are alcohols, ethers, or their mixtures. Particularly preferred such alcohols which contain from 1 to 4 carbon atoms. Good isopropanol. Of course, you can repeat several times the leaching of organic liquid and apply several organic liquids. At the exit of the washing, it is desirable to separate the gel from at least part of the water and used organic liquid by centrifugation or filtration.

In the preparation method of the carrier according to the invention the washed gel is subjected to drying by distillation to evaporate the water and organic liquid that is not removed previously, to obtain a powder carrier. The distillation can be performed at atmospheric or under reduced pressure. Primarily working at atmospheric pressure.

In a special variant of this formula implementation for washing gel choose organic Alenia at least 95%, mostly at least 98% of the water and part of the organic liquid, and thereafter, the gel still has the remainder of the organic liquid. In this particular embodiment, depending on the amount of water present in the gel after washing, it is sometimes necessary to add an additional amount of organic liquid to the washed gel to provide maximum removal of water in the form of an azeotropic mixture of water and organic liquid. In this particular embodiment, the output from drying to produce a powder containing the usual amount of moisture below 1 wt.%, mostly below 0.5 wt.%, for example, less than 0.2 wt.%.

At the exit of the drying distillation of the selected powder carrier, which if necessary can pass through a sieve to separate from it the particles of undesired size. This powder is subjected to calcination. The annealing aims extraction at elevated temperature organic impurities from the powder. It usually continue up until the weight of the powder does not remain constant during this time, avoiding crystallization of the powder. The calcination can be performed in an atmosphere of air (primarily dry air) in the fluidized bed at temperate 1000oC, mainly from 400 to 600oC.

In the preparation method of the carrier according to the invention it may be desirable crushing the gel precursor obtained in the above-mentioned third stage, then the suspension in the liquid, followed by spraying a suspension of the precursor gel. As a liquid, you can use any dispersant, relatively inert gel, for example, water. Then particles selected from sputtering, and subjected to successive washing with water and organic liquid, drying, distillation and calcination as described above. Alternatively, sputtering can be performed after washing with water.

The preparation method of the carrier according to the invention allows to obtain media containing mixed oxide of silicon and aluminum and/or phosphorus with a uniform distribution of components, combining high specific surface area and larger pore volume with high resistance to crystallization from amorphous state.

Taking into account its physical and structural characteristics, the media according to the invention finds a particularly interesting application as a carrier for catalysts in the polymerization of olefins; the catalyst preimushestvenno, contains advanced titanium and obtained particularly advantageous variant implementation, described above, allow to obtain catalysts for the manufacture of polyolefins with good mechanical properties. In addition, the presence of titanium in the media, you can get a polyolefin with a very variable flow index.

The invention relates also to a catalyst for polymerization of olefins containing chromium on the media according to the invention defined above.

The catalyst according to the invention can be obtained in a known manner by impregnation of the powder carrier aqueous or organic solution of a compound of chromium, followed by drying in an oxidizing atmosphere. With this purpose you can use the chromium compound selected among soluble salts such as oxide, acetate, chloride, sulfate, chromate and bichromate in an aqueous solution, or as acetylacetonate in aqueous solution. After impregnation of the carrier with the chromium compound impregnated carrier is usually activated by heating at a temperature of from 400 to 1000oC to convert at least part of the chromium is hexavalent chromium.

The catalyst according to the invention can also be obtained by using mechanical) is artelino to activate at a temperature below the melting temperature of the compounds of chromium, before activating when the conditions listed above.

Alternatively, the chromium compound can also be incorporated into the powder carrier during manufacture of the latter or at the time of manufacture of the precursor gel of the media. To this end, for example, to add to, partially or completely, in an acidic solution of aluminum compounds and/or source of phosphate ions used in the second stage of the method of manufacturing the precursor gel according to the invention, to choosedate chromium oxide simultaneously with the oxide of silicon, aluminum and/or phosphorus. You can also add the chromium compound to the precursor gel before puberty or after puberty last.

In the catalyst according to the invention, chromium is usually present in an amount which varies from 0.05 to 10 wt.%, mainly from 0.1 to 5 wt.%, especially from 0.25 to 2 wt.% based on the total weight of the catalyst.

The catalyst according to the invention is particularly effective in the polymerization of olefins. In fact, for this application, the catalyst according to the invention has a number of advantages:

- increased catalytic activity even in the absence of co-katalizatornoi to hydrogen;

this catalyst allows to obtain polyolefins having:

the distribution of molecular weights between srednechirchik and very wide for this flow index, and

a small content of oligomers.

The catalyst according to the invention can be used for the polymerization of olefins containing from 2 to 8 carbon atoms per molecule, and especially for the production of homopolymers of ethylene or copolymers of ethylene with one or more comonomers selected among the olefins described above. Mainly comonomers are propylene, 1-butene, 1-penten, 3-methyl-1-butene, 1-hexene, 3 - and 4-methyl-1-pentene and 1-octene. Diolefin containing from 4 to 18 carbon atoms, can also be copolymerizable with ethylene. Mainly diolefine are such aliphatic unpaired diolefine as 4-vinylcyclohexane, or alicyclic diolefin with industrijski bridge, such as Dicyclopentadiene, methylene and ethylidene-norborne, and such conjugated aliphatic diolefin as 1,3-butadiene, isoprene and 1,3-pentadiene.

The catalyst according to the invention is particularly well suited for the production of homopolymers of ethylene and copolymers containing at least 90%, becoming the 1-octene.

The invention relates also to a method for the polymerization of these olefins defined above, using the catalyst according to the invention. In the polymerization method according to the invention the polymerization can be performed in solution, in suspension in a hydrocarbon diluent or in the gas phase. Good results were obtained when polymerization in suspension.

The polymerization in suspension is carried out in a hydrocarbon diluent such as liquid aliphatic, cycloaliphatic and aromatic hydrocarbons, at a temperature such that at least 80% (mostly at least 90%) formed polymer in them insoluble. The preferred solvents are alkanes with a straight chain, such as ad-butane, n-hexane and n-heptane, or alkanes branched chain, such as isobutane, isopentane, isooctane and 2,2-DIMETHYLPROPANE, or cycloalkanes such as cyclopentane and cyclohexane or mixtures thereof.

The polymerization temperature usually selected between 20 and 200oC, mostly between 50 and 150oC, especially between 80 and 115oC. the Pressure of ethylene often choose between atmospheric pressure and 5 MPa, mostly between 0.4 and 2 MPa, in particular between 0.6 and 1.5 MPa.

Polymerization of monoclone polymerization (temperature, the possible content of the co monomer, a possible hydrogen content, the type of environment polymerization in a single reactor differ from the conditions used in the other reactors.

Examples 1 to 6, the description which follows below, serve to illustrate the invention. In these examples, first prepared precursor gels carriers for catalysts. Then used these gels for preparation of media. Then put the catalysts for these carriers. Used the obtained catalysts media for polymerization of ethylene.

In examples 5 and 6 titanium included in the precursor gel.

Values used symbols expressing the above variables and methods of measurement of these quantities are explained below.

UE = specific surface of the carrier, as measured by the method of penetration of nitrogen titrimetrically method British standards BS 4359/1 (1984).

VP = pore volume of the carrier is equal to the sum of the pore volume formed by pores of radius less than or equal to 75 as measured by the method of penetration of nitrogen titrimetrically method British standards 1354359/1 (1984), and pore volume, measured by a method of mercury penetration using porosimetry type PORO 2000, manufactured in the sale of the company Carli using a method above.

FD = fraction of oligomers in the polymer, expressed in grams of oligomers per 1 kg of the polymer measured by extraction with hexane at a temperature of boiling hexane.

= catalytic activity, expressed in grams of polymer obtained per 1 hour and 1 gram of the used catalyst, and divided by the partial pressure of olefin, expressed in bars.

Tind= induction time, expressed in minutes and is defined as the time elapsing between the introduction of ethylene and the emergence of pressure reduction characteristic of the beginning of the polymerization.

HLM1 = flow index of the polymer with a melting point 190oC, measured at a load of 21.6 kg and expressed in g/10 min according to standards ASTM 1238 (American society for testing and materials) (1986).

0/2= the ratio between the dynamic viscosity (0), expressed in Pa. sec. and measured by the velocity gradient of 1-s1and at 190oC, and the dynamic viscosity (2), expressed in Pa. sec. and measured by the velocity gradient 100-s1and when 90oC.

Examples 1 - 4 (in accordance with the invention)

A. Preparation of the gel precursor

a) the First stat>C, a solution of water and 1 molar hydrochloric acid, to obtain the concentration of H+0,1 M Number of tetraethylene silicon, ethanol, water and hydrochloric acid, which was used, is presented in table 1. Then the hydrolysis medium was subjected to ripening at 60oC within 2 hours.

b). The second stage

Prepared an aqueous solution containing hydrated aluminum chloride and phosphoric acid used number is presented in table 1. Then add the resulting solution to the hydrolysis medium obtained in (a), under vigorous stirring and at 10oC.

C). The third stage

Was added to 500 g of an aqueous solution of ammonium hydroxide to pH 8, temperature-controlled at 10oC, the mixture obtained in (b), maintaining the pH constant at the value of 8, to effect gelation.

about). Aging

Were subjected to the gel obtained in (C) aging at pH 8, for 2 hours, under weak stirring and at 60oC.

B. Preparation of catalyst carrier

a) Flushing.

Washed the gel obtained in A first 3 times with water, then 1 time with isopropanol.

b). Drying

From the washed gel obtained in (a), drove azeotropic m under reduced pressure to obtain a powder, in which the moisture content is below 1 wt.%.

(C) Annealing.

Was progulivali the powder obtained in (b), in the fluidized bed by blowing dry air for 4 hours at 500oC. Selected powder media whose composition (molar % of silicon dioxide, aluminum oxide and aluminum phosphate), specific surface area, pore volume and temperature of crystallization are presented in table. 1.

C. Preparation of catalyst

Mixed media obtained in B, with chromium acetylacetonate in an amount such that the mixture contained 0.7 wt.% chromium. Then processed the resulting mixture in the fluidized bed at 150oC for 2 hours while blowing dry air. Then progulivali her in the fluidized bed at 700oC for 5 hours in an atmosphere of dry air, and selected catalyst.

D. Polymerization of ethylene

a) Polymerization in the absence of hydrogen

In the autoclave with a volume of 3 liters, previously dried and equipped with a stirrer, were introduced 100 g of the catalyst obtained in C, and 1 liter of isobutane. The temperature was raised to 99oC and introduced into the autoclave ethylene at a partial pressure of 1.09 MPa. The pressure of ethylene and the temperature was maintained constant throughout vremena particles, the properties which are listed in table 2, and also the activity of the catalyst.

b). Polymerization in the presence of hydrogen

Repeating the same operations, introducing into the autoclave, in addition, hydrogen at a partial pressure of 0.44 MPa. The results obtained are also included in the table. 2.

Examples 5 and 6 (in accordance with the invention)

A. Preparation of the precursor gel

a). The first stage

Add, drop by drop, a solution of tetraethylene silicon and ethanol, thermostated at 10oC, a solution of water and 1 molar hydrochloric acid to obtain the concentration of H+0,1 M number of tetraethylene silicon, ethanol, water and hydrochloric acid, which are used, are presented in table. 3. Then subjected received hydrolytic environment ripening at 60oC for 1 hour. Then was added a solution of titanium acetylacetonate in isopropanol in an amount necessary to obtain a titanium content specified in the table. 3. Ripening was continued for 1 hour at 60oC, which was maintained at pH 1 by adding an adequate amount of hydrochloric acid.

b). The second stage

Prepared an aqueous solution containing hydrated aluminium chloride and phosphate is e, obtained in (a), under vigorous stirring and at 10oC.

c). The third stage

Was added to 500 g of an aqueous solution of ammonium hydroxide to pH 8, thermostatting at 10oC, the mixture obtained in (b), maintaining the pH constant at the value 8 in order to carry out gelation.

d). Aging

Were subjected to the gel obtained in (c), aging at pH 8, for 2 hours, under weak stirring and at 60oC.

B. Preparation of catalyst carrier

a). Flushing

Washed the gel obtained in A first 3 times with water, then 1 time with isopropanol.

b). Drying

From the washed gel obtained in (a), drove azeotropic mixture of water-isopropanol at atmospheric pressure, then isopropanol, first at atmospheric pressure and then under reduced pressure to obtain a powder in which the moisture content is below 1 wt.%.

c). The calcination

Was progulivali the powder obtained in (b), in the fluidized bed by blowing dry air for 4 hours at 500oC. Selected powder media whose composition (mole percent silicon dioxide, aluminum oxide and aluminum phosphate), specific surface area, pore volume and temperaturechanges in B, with chromium acetylacetonate in an amount such that the mixture contained to 0.63 wt.% chromium. Then process the mixture in the fluidized bed at 150oC for 2 hours while blowing with dry air and the selected catalyst.

D. Polymerization of ethylene

In the autoclave with a volume of 3 liters, previously dried and equipped with a stirrer, were administered 100 mg of the catalyst obtained in C, and 1 liter of isobutane. The temperature was raised to 104oC in the autoclave was introduced ethylene at a partial pressure specified in table IV. If necessary in the autoclave was introduced, in addition, the hydrogen at the pressure specified in the table. 4. The pressure of ethylene and the temperature was maintained constant during the time required to obtain a certain amount of polyethylene. After degassing of the selected polymer in the form of particles whose properties are given in table. 4 as the catalyst.

The invention is illustrated in the drawing.

1. Carrier for catalysts for the polymerization of olefins containing silicon dioxide, aluminum phosphate and, if necessary, aluminum oxide, characterized in that it has a specific surface area of 100 to 800 m2/g, a crystallization temperature above or equal to 70 the structure:

Pack < (OP 564 - 358),

in which the UE and OP, respectively, the numerical values of the specific surface, expressed in m2/g, and pore volume, expressed in cm3/,

2. Media under item 1, characterized in that it consists of two components, one of which is silicon dioxide (a) and the other (B) aluminum phosphate, in molar percentages : () (10 - 95) : (90 - 5).

3. Media under item 1, characterized in that it contains silicon dioxide (X), aluminum oxide (V) and aluminum phosphate (Z) in molar percent (X) : (V) : (Z) (10 - 95) : (1 - 80) : (1 - 85).

4. The carrier according to any one of paragraphs.1 to 3, characterized in that it contains in addition, titanium in the amount, expressed in TiO2from 0.1 to 40 mol.%.

5. The carrier according to any one of paragraphs.1 to 4, characterized in that it has the standard volume weight of from 50 to 500 kg/m3.

6. A method of manufacturing a gel-predecessor of the carrier of catalysts for the polymerization of olefins, which are mixed in the first stage, alcohol, water, an alcoholate of silicon and acid in such quantities that the molar ratio of water to silicon was from 2 to 50, add to the resulting hydrolytic environment in the second stage, the acidic solution of the aluminium compound and/or a solution of a phosphate ion source, and NaN in the first stage mixing water, acid, silicon alcoholate and alcohol at a temperature below or equal to 30oWith and subsequent maturation received hydrolytic environment at a temperature at least equal to the 20oWith and below the boiling point of the medium, and displacing at least part of the groups alkoxyl alcoholate of silicon hydroxyl groups without precipitation or gelation of the silica.

7. The method according to p. 6, characterized in that the silicon alcoholate is aliphatic alcoholate of silicon.

8. The method according to p. 7, characterized in that the silicon alcoholate is Tetra-ethylate silicon.

9. The method according to any of paragraphs.6 to 8, characterized in that the acid used in the first stage, is hydrochloric acid.

10. The method according to any of paragraphs.6 to 9, characterized in that the first stage is used, in addition, the titanium alcoholate.

11. The method according to p. 10, characterized in that the titanium alcoholate add during maturation.

12. The method according to p. 10 or 11, characterized in that the alcoholate of titanium is titanium acetylacetonate.

13. The method according to any of paragraphs.6 to 12, characterized in that the connection of aluminum selected from inorganic salts of aluminum and Alize aluminum nitrate and aluminum chloride.

15. The method according to any of paragraphs.6 to 14, characterized in that the source of phosphate ions is phosphoric acid.

16. The method according to any of paragraphs.6 to 15, characterized in that the gelling agent is an aqueous solution of ammonium hydroxide.

17. The method according to any of paragraphs. 6 to 16, characterized in that the first stage carry out ripening at 50 - 70oC.

18. The method according to any of paragraphs.6 to 17, characterized in that the second stage is carried out at a temperature below or equal 20oC.

19. The method according to any of paragraphs.6 to 18, characterized in that the third stage is carried out in an environment with constant pH, the value of which 6 to 10, and if the temperature is below or equal to 30oC.

20. The method according to any of paragraphs.6 - 19, characterized in that the selected output from the third stage, the gel is subjected to aging.

21. The method according to p. 20, characterized in that the aging of the gel is carried out at a temperature which can vary from room temperature to the boiling temperature of the environment, aging, and at pH above or equal to 6.

22. The preparation method of the carrier of catalysts for the polymerization of olefins which is prepared gel precursor by the method according the Cabinet and calcined powder.

23. The method according to p. 22, characterized in that the organic liquid is chosen from alcohols.

24. The method according to p. 23, characterized in that the organic liquid is isopropyl alcohol.

25. The method according to any of paragraphs.22 to 24, characterized in that the drying is carried out by distillation of the azeotropic mixture of water and organic liquid to remove at least 98% of water and the organic liquid is then distilled off, the remaining part of the organic liquid.

26. The catalyst for polymerization of olefins containing chromium on a carrier, characterized in PP.1 - 5.

27. The method of polymerization of olefins, in the exercise of which used the catalyst p. 26.

28. The method according to p. 27, which is subjected to the polymerization of ethylene.

 

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