Enhanced carriers from aluminium oxide and silver-based catalysts for producing alkylene oxides

FIELD: chemistry.

SUBSTANCE: invention relates to methods of producing carriers from aluminium oxide which have desirable properties when used as carriers for silver-based catalysts. The method of making a modified catalyst carrier for vapour-phase epoxidation of alkene involves a) saturation of a moulded carrier made from alpha aluminium oxide, which has been burnt and optionally subjected to other types of processing which provide for preforming, as part of the preforming process with at least one modifier, chosen from silicates of alkali metals and silicates of alkali-earth metals; b) drying said saturated carrier and c) burning said dried carrier at temperature not below 800°C. To obtain the catalyst, the method additionally involves stage d) where silver catalytic material is deposited on the said dried carrier. The invention also relates to epoxidation reactions, carried out in the presence of catalysts given above.

EFFECT: invention provides for highly stable activity and/or efficiency and acceptable initial efficiency and activity.

15 cl, 14 ex, 7 tbl

The application cross-reference

This application claims the priority of provisional patent application U.S. No. 60/497452, registered on August 22, 2003.

The technical field to which the invention relates

This invention relates to methods for media aluminum oxide having desirable properties when used as carriers for catalysts based on silver. This invention relates also to the native aluminum oxide, obtained by applying the methods of the invention, and epoxidation reactions conducted in the presence of catalysts based on silver, deposited on such a native oxide of aluminum.

The prior art inventions

Getting accelerated, such as ethylene oxide, reaction of oxygen or oxygen-containing gases with ethylene in the presence containing silver catalyst at elevated temperature is an old and well-known manner. For example, in U.S. patent No. 2040782, dated may 12, 1936, describes the production of ethylene oxide by the reaction of oxygen with ethylene in the presence of silver catalysts that contain a class of metal-containing promoters. In reissued U.S. patent 20370, dated may 18, 1937, Leforte described that the formation of oxides of olefins can be carried out by the interaction of olefins neposredno is but with molecular oxygen in the presence of a silver catalyst (an Excellent discussion on ethylene oxide, including detailed discussion of commonly used stages of production method, available in Kirk-Othmer''s Encyclopedia of Chemical Technology, 4^thEd. (1994) Volume 9, pages 915-959).

The catalyst is the most important element in the direct oxidation of ethylene to obtain ethylene oxide. There are several well-known components of the catalyst active metal catalyst (usually silver, as described above); a suitable substrate/carrier (for example, alpha-alumina) and the promoters of the catalyst, all of which may play a role in improving the performance characteristics of the catalyst. Due to the importance of the catalyst upon receipt of ethylene oxide much effort has been spent to improve the efficiency of the catalyst upon receipt of ethylene oxide.

Application and/or the inclusion of silicon dioxide or silicates during retrieval of the substrate/carrier used to improve the operational characteristics of the catalysts made on the basis of such media, in General, are known and described in several references of the prior art: for example, in U.S. patents№№ 4272443; 4428863; 4575494; 4645754; 4769358; 5077256; 5100859; 6281370; 6313325 and 6579825; WO 97/46317 and in the application for U.S. patent No. 2003/00092922 A1. It should be noted, however, that in none of these links is not described or not, it is assumed that described in the present invention, CR is the application of the claimed silicates for processing after molding, additional processing for the pre-molded carrier to further improve the performance characteristics of the resulting catalysts based on silver, obtained with the use of such media.

To describe some of the parameters of the catalytic system for epoxidation of alkenes is usually used several terms. For example, the term "degree of transformation" is defined as the molar percentage of alkene introduced into the reactor, which reacts. Of the total number of alkene, which turns into a different chemical compound, the molar percentage, which is converted into the corresponding epoxide of alkylene, known as "efficiency" (which is synonymous with "selectivity") this way. The product obtained by multiplying the percentage efficiency of the interest rate (divided by 100 percent (%) for conversion of %²in %)is the percentage of "exit", i.e. a molar percentage supplied alkene, which is converted into the corresponding epoxide.

"Activity" of the catalyst can be quantified in a number of ways, one of them is the mole percent of the epoxide of alkylene contained in the output stream of the product of the reactor relative to the molar percent in the incoming stream (molar percent epoxide of alkylene in the incoming photocopie, but not necessarily, is zero percent), while the temperature of the reactor to maintain essentially constant, and the other is the temperature required to maintain this rate of formation of oxide alkylene. That is, in many cases, the activity is measured over a period of time, expressed as mole percent of the epoxide of alkylene obtained at a certain constant temperature. In the alternative case, the activity can be measured as function of temperature required to maintain get a specific permanent molar percent epoxide of alkylene. Suitable service life of the reaction system is the length of time during which the reactants can be passed through the reaction system and for which the results are considered by the operator as acceptable in the light of all factors considered.

The term "decontamination"used here refers to the permanent loss of activity and/or efficiency, that is, decrease in activity and/or efficiency, which cannot be recovered. As mentioned above, getting the epoxide of alkylene can be increased by increasing temperature, but the need for operating at a higher temperature to maintain a certain speed education is a characteristic d is I the decontamination activity. Reduced activity and/or efficiency tends to occur more quickly when using a higher reaction temperature. "Stability" of the catalyst is inversely proportional to the rate of deactivation, i.e. the rate of decrease in the efficiency and/or activity. Usually are desired lower speed reduced efficiency and/or activity.

In order to be considered satisfactory, the catalyst should be of acceptable activity and efficiency, and the catalyst must have sufficient stability so that it could be quite a long usable life. When efficiency and/or activity of the catalyst decreases to unacceptable levels, the reactor is usually shut down and partially disassemble to remove the catalyst. This leads to loss of time, productivity and materials, for example, silver catalytic material and a carrier of aluminum oxide. In addition, the catalyst must be replaced and silver should be restored or, where possible, recycled. Even when the catalyst is able to be regenerated in situ, usually the formation of the product is stopped for a certain period of time. In the best case, the replacement or regeneration of the catalyst requires additional losses in production time for processing is utilizator and in the worst case, requires replacement of the catalyst with the resulting rise in the cost of products. Therefore, it is desirable to find ways of lengthening the useful life of the catalyst.

Because even small improvements in the service life of the catalyst can be set for commercial production on a large scale, it is desirable to get the media and the resulting catalyst (as well as the way to achieve this), which has improved stability with acceptable efficiency.

The invention

One aspect of the present invention relates to the native oxide of aluminum, which provide enhanced stability activity and/or efficiency, and acceptable initial efficiency and activity, and the manner in which such media are produced, for improving the operational characteristics of the already molded and calcined carrier. More specifically, the invention relates to a method of post-processing to further improve the carrier used in the catalyst for the production of accelerated, such as ethylene oxide. Accordingly the present invention provides a method of obtaining modified carrier for a catalyst, which is used for gas-phase epoxidation of alkene, comprising a) impregnation p is evritania molded carrier of alpha-aluminum oxide, at least one modifier selected from alkali metal silicates and alkaline earth metal silicates; (b) drying the specified impregnated carrier, and (C) annealing the dried specified media.

Another aspect of the present invention is optional washing of the modified media to achieve additional benefits.

Another aspect of the present invention is a modified carrier obtained according to the method described here, and the catalyst on the basis of such media. The improved catalyst of the present invention can also be obtained with the optional inclusion of increasing its efficiency promoters are well known in this field.

Another aspect of the present invention is a method of obtaining accelerated, for example of ethylene oxide using the catalyst obtained from the modified carrier of the present invention.

Although the present invention is not limited by any theories, it is believed that a possible explanation for the mechanism described here modifications is that the modifier(s) reacts with the surfaces of microscopic particles of aluminum oxide contained in a pre-molded carrier of alpha-aluminum oxide, and as a result affects one or more its the TV, for example roughness, crystallinity, chemical composition, and so forth, of the surfaces of microscopic particles of aluminum oxide, without significant changes of the morphology, distribution of pore volume and/or pore size and, in some cases, the surface area of the pre-molded carrier of alpha-aluminum oxide. It is believed that as a result of this mechanism, any of the modifications of the present invention can be carried out on aluminum oxide which has been calcined and which preferably may already have the desired morphology, surface area, pore size distribution and/or pore size, surface modification of pre-formed carrier of alpha-aluminum oxide by a method that provides improved efficiency, activity and/or stability. The next distinguishing feature of the present invention is that the pre-molded carrier of alpha-aluminum oxide may be a material that can be used as a carrier as such, i.e. without modification of the present invention. For example, a pre-molded carrier of alpha-aluminum oxide may include material that is suitable for use as a carrier for catalyst for epoxidation based on silver.

Young is a great description of the invention

As stated above, there is proposed a method of obtaining a carrier for a catalyst, comprising impregnating a pre-formed carrier of alpha-aluminum oxide, at least one modifier selected from alkali metal silicates and alkaline earth metal silicates, getting drenched, pre-molded carrier of alpha-aluminum oxide; drying the impregnated pre-formed carrier of alpha-aluminum oxide to obtain a dried impregnated alumina, and calcining the dried impregnated alumina to obtain a modified carrier of aluminum oxide.

Pre-molded carrier of alpha-aluminum oxide includes aluminum oxide, i.e. it can contain essentially only the aluminum oxide (with the inevitable or small impurities) or in combination with one or more other materials.

Aluminium oxide for use in accordance with this aspect of the invention is not limited, it can include any type of aluminum oxide, suitable for use in the manufacture of the carrier, and such materials are well known and widely available. For example, the aluminum oxide used in the manufacture of carriers for catalysts based on silver, for example, to receive the of epoxides of alkylene, well described in the patent literature (some of the earlier of these patents, including, for example, U.S. patent No. 2294383, 3172893, 3332887, 3423328 and 3563914, hereby incorporated here by reference in their entirety). Used aluminum oxide, which has a very high purity, that is at least 98 wt.% alpha-alumina, and any other components are oxides of silicon, oxides of alkali metals (e.g. sodium oxide) and trace amounts of other metal-containing and/or metal containing additives or impurities. Similarly, there was used an aluminum oxide with a lower purity, that is, approximately 80 wt.% alpha-aluminum oxide, and the remainder had one or more components of the amorphous and/or crystalline aluminum oxide and other oxides of aluminium, silicon dioxide, aluminum silicate, mullite, various oxides of alkali metals (e.g. potassium oxide and cesium oxide), oxides of alkaline earth metals, oxides of transition metals (such as iron oxide and titanium oxide and other oxides of metals and nonmetals. Furthermore, the material used for the manufacture of the carrier, may include compounds which are known to improve the operational characteristics of the catalyst, for example rhenium (such as Renata) and molybdenum.

The expression "pre-sformo the p carrier of alpha-aluminum oxide" should be understood as including any material obtained by the implementation (aluminum oxide or composition, which includes aluminum oxide) any sequence of treatments, which include at least one calcination, that is, the expression "pre-molded carrier of aluminum oxide" includes any of the many pre-molded material carriers of alpha-aluminum oxide, which are commercially available. The methods of the present invention, therefore, include, for example, the ways in which pre-formed carrier material of the alpha-alumina is used as the source material and the carrier is impregnated with a modifier, followed by drying and calcination, and means, comprising calcining aluminum oxide with the formation of the pre-molded carrier of alpha-aluminum oxide, then the impregnated pre-formed carrier of alpha-aluminum oxide modifier, followed by drying and calcination.

As described above, the modification of the present invention can be carried out in such a way that the influence on the surface properties of microscopic particles of aluminum oxide could be without significant changes to the morphology, surface area, distribution of pore volume, pore size and/or volume of platnost the pre-molded carrier of alpha-aluminum oxide. As a result, when the pre-molded carrier of alpha-alumina having the shape, morphology, surface area, pore size distribution, pore size and bulk density, which is desirable for the media, modify the present invention, the resulting shape, morphology, surface area, pore size distribution, pore size and bulk density of the modified carrier of aluminum oxide are also desirable for the media. In accordance with this pre-molded carrier of alpha-aluminum oxide preferably has the shape, morphology, surface area, pore size distribution, pore size and bulk density, which is desirable for the carrier of aluminum oxide.

Suitable forms for the pre-molded carrier of alpha-aluminum oxide, therefore, include any of a wide variety of forms known in the media, including particles, lumps, pieces, pellets, rings, spheres, disks, toroids having on interior or exterior surfaces form stars, and the like, with a size suitable for use in reactors with a fixed layer. Conventional commercial reactors fixed bed to obtain epoxide, ethylene, usually in the form of multiple parallel elongated the output tubes (in a suitable enclosure) with an outer diameter of 1-3 inches and a length of 15-45 feet, filled with catalyst. In such reactors, fixed bed, it is desirable to apply the medium, made in the form of rounded forms, such as, for example, spheres, pellets, rings, tablets and the like, having diameters of from about 0.1 inch to about 0.8 inch.

Representative examples of materials that can be used as a pre-molded carrier of alpha-alumina of the present invention include the native aluminum oxide, manufactured by Süd Chemie, Inc., Louisville, Ky., and the native aluminum oxide, manufactured by Saint-Gobain NorPro Corporation, Akron, Ohio.

Of the many known ways to obtain a pre-molded carrier of alpha-alumina having desirable properties (e.g., having a desired morphology, surface area, pore size distribution and/or pore size) is one such method includes forming (for example, by extrusion or pressing) of alumina powder (preferably powder of alpha-aluminum oxide) to obtain a molded alumina and calcining to obtain pellets of a pre-molded carrier of alpha-aluminum oxide.

Another well-known method of obtaining a pre-molded carrier of alpha-alumina having desirable properties, including the t in the mixing aluminum oxide (preferably, alpha-alumina) with a binder to obtain a mixture, molding (e.g., extrusion or pressing) mixture to obtain a molded mixture and then annealing the molded mixture to obtain granules pre-molded carrier of alpha-aluminum oxide.

Pre-molded carrier of alpha-alumina of this method is the pore size distribution, on which:

less than 20 vol.% (more preferably 0-5%vol.) pores have a diameter less than 0.1 microns;

5-30 vol.% (more preferably 5-20 vol.%) pores have a diameter of 0.1-0.5 microns;

7-30% vol. (more preferably, 10-25 vol.%) pores have a diameter of 0.5-1.0 microns;

more than 10% vol. (more preferably, 10 to 40 vol.%) pores have a diameter of 1.0 to 10 microns;

more than 20 vol.% (more preferably 30-55%vol.) pores have a diameter of 10-100 microns and

4-20% vol. (more preferably 6-20%vol.) pores have a diameter of at least 100 microns.

Another well-known method of obtaining a pre-molded carrier of alpha-alumina having desirable properties, includes peptization of aluminum oxide in the form of boehmite and/or γ-alumina in an acid mixture containing halide anions (preferably fluoride anions) with the formation of halogenated alumina, forming (for example, by extrusion or pressing) with education is the Finance halogenated alumina, drying the molded halogenated alumina to obtain the dried formed alumina, and calcining the dried formed alumina with obtaining granules pre-molded carrier of alpha-aluminum oxide. When using a pre-molded carrier of alpha-alumina, which was obtained as described above in this paragraph, it is important that the aluminum oxide, which was Patision acid mixture containing halide anions, was calcined before impregnation, at least one modifier, since the halide is required for forming plates of alpha-alumina in a pre-molded carrier of alpha-aluminum oxide. If halogenated alumina impregnated with at least one modifier without conducting a first annealing halogenated alumina after peptization of the alumina in the form of boehmite and/or γ-aluminum oxide, the at least one modifier will lose some or essentially all of the amount of the halide anions, which then will not be available to assist in the molding plates of alpha-aluminum oxide.

Pre-molded carrier of alpha-aluminum oxide obtained by this method (that is, before impregnation, at least one mod is fication of the present invention), preferably has a specific surface area of at least approximately 0.7 m²/g (more preferably, from about 0.7 m²/g to about 10 m²/g), pore volume of at least approximately 0.5 cm³/g (more preferably, from about 0.5 cm³/g to about 2.0 cm³/g), a purity of at least 98 wt.% alpha-aluminum oxide, the average pore diameter of from about 1 to about 50 microns. Pre-molded carrier of alpha-aluminum oxide preferably comprises particles, each of which has at least one essentially flat main surface, having a layered or lamellar morphology, which is approaching the form of hexagonal plates (some particles have two or more flat surfaces), at least 50% (by number) have a principal amount of less than about 50 microns. Pre-molded carrier of alpha-alumina obtained by any suitable method as described above is impregnated with at least one modifier selected from alkali metal silicates and alkaline earth metal silicates. This impregnation can be performed in any suitable way. One preferred method of impregnating a pre-formed media and is ha-alumina carried out by dissolving, at least one modifier in the solvent to form solution for impregnation and vacuum impregnation of a pre-molded carrier of alpha-alumina with a solution for impregnation. Alternatively, the application of the solution, emulsion or suspension containing at least one modifier, can be performed on the media.

The preferred composition for impregnation of the present invention include at least one alkali metal silicate in solution, preferably in water. With regard to aqueous solutions, it is known that various alkali metal silicates have different respective ranges of solubility in different solvents and therefore ranges that can be selected concentration of alkali metal silicates, are governed by the solubilities of the applied compound, the specific alkali metal silicate. Composition for impregnation may optionally contain one or more other materials, for example a promoter, stabilizer, surfactant or the like.

As described above, according to the first aspect of the present invention after impregnation of the pre-molded carrier of alpha-aluminum oxide, at least one modifier selected from alkali metal silicates and silicates deliciosamente what's metals, impregnated, pre-molded carrier of alpha-aluminum oxide is dried. The drying is preferably carried out at a temperature not exceeding about 250 degrees Celsius, for at least the first two hours after treatment. Such drying can be performed by any suitable method, for example, the location of the aluminum oxide in the dryer or curing of aluminum oxide in the environment (for example, at room temperature), for example, regulation or without humidity control and/or by blowing or without a blowing gas, or any other processing, which leads to drying. The invention is not limited to any particular method of drying, and this aspect of the invention includes all methods that are described herein and in which drying is achieved, regardless of how such drying is achieved. Preferably, during at least the first two hours after impregnation temperature of aluminum oxide, preferably, does not exceed 250 degrees Celsius. The drying is preferably carried out orderly manner, preferably, includes humidity control to achieve a uniform distribution of the modifier on the pre-molded carrier of alpha-aluminum oxide.

In a representative embodiment, Khujand is the implementation of treatment drying, held in the drying chamber, the drying is carried out in a drying chamber at a slow temperature rise to maximum, from about 100 degrees Celsius to about 250 degrees Celsius, most preferably a maximum of approximately 150 degrees Celsius, for a period of from about 2 to 12 hours, most preferably about 4-6 hours and then cooled back to approximately room temperature over the next 1/2 hour to 2 hours. For example, a representative example of a suitable sequence of operations of drying includes the location impregnated, pre-molded carrier of alpha alumina in the drying chamber and a slow increase in temperature up to a maximum of not higher than 150 degrees Celsius, and keeping at this temperature for a suitable period of time, for example 2 to 12 hours. As another example, another specific example of a suitable sequence of drying includes raising the temperature from room temperature to about 50 degrees Celsius in the first 45-75 minutes, preferably 60 minutes, increasing the temperature from about 50 degrees Celsius to about 75 degrees Celsius in the following 45-75 minutes, preferably 60 minutes, increasing temperatureprofile from 75 degrees Celsius to about 100 degrees Celsius in the following 45-75 minutes preferably, 60 minutes, increasing the temperature from 100 degrees Celsius to about 150 degrees Celsius in the next 45 to 90 minutes, preferably 60 minutes, maintaining the temperature at approximately 150 degrees Celsius in the following 45-75 minutes, preferably 60 minutes, then cooled again to room temperature in the following 45-75 minutes. Another specific example of a possible sequence of operations of drying, and this example includes a higher maximum temperature comprises raising the temperature from room temperature to about 60 degrees Celsius in the first 45-75 minutes, increasing the temperature from about 60 degrees Celsius to approximately 90 degrees Celsius in the next 20-30 minutes, increasing the temperature from 90 degrees Celsius to 150 degrees Celsius in the following 45-75 minutes, increasing the temperature from 150 degrees Celsius to about 250 degrees Celsius in the next 50 to 80 minutes and then cooled back to room temperature.

Pre-molded carrier of alpha-alumina, which was thus impregnated with at least one modifier comprising at least one alkali metal silicate and/or at least one silicate alkaline earth metal, and wysu the Yong, then calcined. If impregnated, pre-molded carrier of alpha-aluminum oxide is not dried before calcination, at least one alkali metal silicate and/or at least one silicate of the alkali earth metal may be less evenly distributed relative to the pre-molded carrier of alpha-aluminum oxide and/or may be present in a smaller total amount. In other words, the drying according to the present invention leads to a better distribution uniformity of at least one alkali metal silicate and/or at least one silicate of the alkali earth metal and reduces or prevents loss of at least one alkali metal silicate and/or at least one alkali earth metal silicate by calcination of the dried impregnated alumina.

The calcination of the dried impregnated alumina is performed by raising the temperature of the dried impregnated alumina for some period of time. The maximum temperature, which is subjected to the dried impregnated alumina, preferably, is at least 800 degrees Celsius, more preferably at least 1200 degrees Celsius.

An example of a suitable annealing includes polineuropathy and dried carrier furnace annealing and the temperature increases from room temperature to approximately 500 degrees Celsius in the first 45-75 minutes preferably, approximately 60 minutes, keeping at approximately 500 degrees Celsius over the next 45-75 minutes, preferably about 60 minutes, increasing the temperature from about 500 degrees Celsius to about 800 degrees Celsius in the following 45-75 minutes, preferably about 60 minutes, keeping at approximately 800 degrees Celsius in the following 45-75 minutes, preferably about 60 minutes, increasing the temperature from about 800 degrees Celsius to about 1200 degrees Celsius in the following 45-75 minutes, preferably about 60 minutes, keeping at approximately 1200 degrees Celsius in the following 90-150 minutes, preferably, about 120 minutes, followed by a substantially linear cooling to 150 degrees Celsius over the next 8-12 hours, preferably for about 10 hours and then the media is removed from the furnace and providing them the opportunity for cooling, for example, to room temperature. In some cases, it was observed that annealing at temperatures higher than 1200 degrees Celsius, for example, 1400 degrees Celsius or higher, leads to obtain the final catalyst, which is even slower aging, and this annealing to higher temperatures (for example, abs Celsius) is sometimes preferred.

Although the present invention is not limited in any way to any particular theory, it is believed that during calcination, at least one alkali metal silicate and/or at least one silicate of the alkali earth metal may react with the surfaces of aluminum oxide, especially in cases where there was a relatively high concentration (e.g., 2 wt.%) modifier (which is at least one alkali metal silicate and/or at least one silicate of alkaline earth metal) in the solution used for impregnation of the modifier. When alpha-alumina impregnated with sodium silicate as a modifier, it is believed that this reaction leads to compounds Na-Al-Si-O aluminum oxide, for example, nepheline (NaAlSiO₄). It is believed that the presence of nepheline means that there is a reaction specified above in this paragraph, however, found that good performance characteristics (i.e. activity, performance and aging) are obtained regardless of whether the nepheline in a modified carrier. If the temperature during the annealing carried out after the impregnation of alpha-aluminum oxide, sodium silicate, approximately 1400 degrees Celsius, also formed the phase carnegieite.

Upon completion of annealing after impregnated the key, at least one modifier selected from alkali metal silicates and silicates of alkaline earth metals, at least one alkali metal silicate and/or at least one silicate of the alkali earth metal is present in an amount which is preferably in the range from approximately 0.01 to approximately a 5.0 weight percent, based on the total weight of the modified carrier of aluminum oxide. When at least one modifier is sodium silicate, the content of sodium silicate, more preferably is in the range from about 0.5 to about 2.0 wt.% after calcination after impregnation modifier.

As stated above, the modification of the present invention does not impact significantly on the morphology and structural properties of unmodified alumina, although the present invention is not limited as such. For example, the morphology of the modified carrier of aluminum oxide is usually essentially similar to the morphology of the pre-molded carrier of alpha-aluminum oxide (i.e. prior to treatment, at least one modifier); the average pore diameter of the modified carrier of aluminum oxide is usually not less than 80% of the average pore diameter of the pre-molded carrier of the LLF-alumina.

Modification of the present invention may significantly affect or not affect the specific surface area. The surface area of the modified carrier of aluminum oxide is usually not less than about 80%, sometimes higher than about 90% and sometimes higher than 95% specific surface pre-molded carrier of alpha-aluminum oxide.

As indicated above, the modified carrier of aluminum oxide according to the present invention preferably washed before impregnation with the catalytic material and/or promotor material.

In accordance with one preferred method of washing according to the present invention for washing the modified media used Soxhlet extraction apparatus. Extractors socket are well known to the person skilled in the art and essentially they include a column in which may be placed in a carrier of aluminum oxide and below which serves the extractant, for example water, which is heated for evaporation, whereby he is held up in the column and through the media to the condenser. The extractant, which is condensed in the condenser falls in the carrier, causing the carrier becomes filled with the extractant. When the media becomes full extractant, the extractant cifonie back in the thread extragenital such extraction according to the present invention, the solvent preferably comprises water and/or one or more amines, and the extraction is preferably carried out for from about 0.2 to about 144 hours, most preferably about 12 hours.

In accordance with other preferred methods of washing according to the present invention, the modified carrier of alumina may be impregnated with water and/or solutions of oxalate amine, and/or other solvents, followed by drying (for example, at a temperature from about 25°C. to about 200°C., for example, approximately 120 degrees Celsius) or annealing (e.g., at a temperature of from about 100°C. to about 1000°C., for example, approximately 500 degrees Celsius).

At least a portion of any excess of cations of alkali metals, alkali metal silicates, alkaline earth metal cations and/or silicates of the alkali earth metal contained in the modified carrier of aluminum oxide may be removed during the washing. Also observed that the phase of nepheline, if it is present, is not removed in significant quantities during such washing, whereas the phase of carnegieite, when it is present, tends to be removed in significant quantities during such flushing.

Any of the media of the present invention may be impregnated with at least one rolled the practical material, and also, optionally, at least one promoter. Alternatively, the coating, of at least one catalytic material and/or at least one promoter may be formed on the medium by application of a solution, emulsion or suspension containing at least one catalytic material and/or at least one promoter.

There are various methods of impregnation of the carrier, at least one catalytic material (and preferably also at least one promoter simultaneously with the catalytic material or in any sequence).

For example, the silver catalysts can be obtained by impregnation of the carrier with a solution of one or more compounds of silver, which is well known in this field. The impregnation of one or more promoters can be carried out simultaneously with the impregnation of silver, before impregnation with silver and/or after impregnation with silver. Upon receipt of such a catalyst carrier impregnated with (one or more times by one or more solutions of compounds of silver, enough to put silver on the carrier in an amount which, preferably, is in the range from about 1% to about 70% by weight of the catalyst, more preferably, from about 10% to about 40% of the mass of the catalyst.

The particle size of the catalytic material is not narrowly critical. In the case of silver catalytic material suitable particle size may be in the range of about 100 to 10,000 angstroms.

There are many well-known promoters, i.e. materials that, when they are present in combination with certain catalytic materials such as silver, improve one or more aspects of the performance characteristics of the catalyst, or otherwise act promotora the ability of the catalyst to form the desired product, for example, ethylene oxide or propylene oxide. Such promoters themselves are usually not considered as catalytic materials. Found that the presence of such promoters in the catalyst contributes to one or more types of beneficial effects on the performance of the catalyst, for example, increasing the speed or quantity of education of the desired product, reducing the temperature required to achieve a suitable reaction rate, the speed decrease unwanted reactions and the number of unwanted products and so on. Competitive reactions take place in the reactor at the same time, and the decisive factor in determining the efficiency of the whole process is a control measure which has over the course of these competitive reactions. M is a material predetermined, known as the promoter of the desired reaction, it may be another reaction inhibitor, for example, the reaction of ignition. Significant is the fact that the effect of the promoter on the overall reaction is favorable for efficient formation of the desired product, for example, of ethylene oxide. The concentration of one or more promoters present in the catalyst may vary within a wide range depending on the desired effect on performance characteristics of the catalyst and other components of a particular catalyst and reaction conditions of the epoxidation.

There are at least two types of promoters - solid promoters and gaseous promoters. Solid promoter introduced into the catalyst prior to its use, either as part of the substrate media, or as part of the active metal component of the catalyst, applied to him. During the reaction of receipt of ethylene oxide particular form of the promoter on the catalyst may be unknown. When a firm promoter added as part of the active catalytic material (e.g., silver), the promoter may be added simultaneously with the same material or sequentially after deposition of metal on a carrier or substrate. Examples of well-known solid promoters for catalysts used to receive the deposits of ethylene oxide, include compounds of potassium, rubidium, cesium, rhenium, sulfur, manganese, molybdenum, tungsten and mixtures thereof.

In contrast, gaseous promoters are gas-phase compounds and their mixtures, which are injected into the reactor to obtain accelerated (e.g., ethylene oxide) with a vapor-phase reactants such as ethylene and oxygen. Such promoters additionally improve the operational characteristics of this catalyst, together with solid carriers, or in addition to them. Commonly used promoter is the gaseous inhibitor (chloride-containing compound) and/or one or more gaseous components capable of generating at least one efficiency-enhancing member of a redox pair of half-reactions, both of which are well known in this field. The preferred gaseous component capable of generating efficiency-enhancing member of a redox pair of half-reactions, is a nitrogen-containing component.

Solid promoters or modifiers are typically added in the form of chemical compounds to the catalyst prior to its use. Used herein, the term "connection" refers to the combination of the particular element with one or more different items related surface and/or himicheskim binding, such as ionic and/or covalent, and/or coordinating binding. The term "ion" or "ion" refers to an electrically charged chemical particle; and "cationic" or "cation" is positive and "anionic" and "anion" is negative. The term "oceniony" or "oxyanion" refers to a negatively charged particle that contains at least one atom of oxygen combined with another element. Oxyanions is, thus, oxygen-containing anion. It is clear that the ions do not exist in a vacuum, but they are found in combination with balancing the charge of the counterions adding in connection to the catalytic Converter.

The catalyst shape promoter is usually unknown, and the promoter can be present without counterion added during the preparation of the catalyst. For example, a catalyst made with cesium hydroxide, can be analyzed on the content of cesium, but not on the content of his protivoyuznogo hydroxide in the final catalyst. Similarly, compounds such as the oxide of an alkali metal such as cesium oxide, and the oxide of the transition metal, for example of Moo₃even though they are not ionic, can turn into ionic compounds during the preparation of the catalyst or in the application. For ease of understanding solid promoters will decree shall be in terms of cations and anions, regardless of the form in the catalyst under the reaction conditions.

Preferably, the catalytic material and optionally one or more solid promoters were relatively evenly dispersed on a modified carrier. The preferred technique for applying silver catalytic material and one or more promoters includes: (1) impregnation of the porous modified carrier of aluminum oxide according to the present invention with a solution comprising a solvent or solubilizers agent, a complex of silver and one or more promoters and 2), then the processing of the impregnated carrier to convert the salt of silver in metallic silver and implementation deposition of silver and promoter(s) on the outer and inner surfaces of the pores of the support. To achieve reproducibility in the application and the second application solutions for impregnation of the carrier preferably should not contain excessive amounts of ions, which are soluble in the solution used for impregnation and/or replaceable promoter supplied to the catalyst, either upon receipt or use of the catalyst, so as to have a significant impact on the amount of the promoter, which provides the desired improvement of the catalyst. If the media contains such ions, ions usually remove the standard is chemical methods, such as leaching or washing, in other words, they should be taken into account during the preparation of the catalyst. Deposition of silver and promoter usually performed by heating the carrier at elevated temperatures to evaporate the liquid in the media and to perform the deposition of silver and promoters on the inner and outer surfaces of the carrier. The impregnated carrier is the preferred method for the deposition of silver, because it uses silver is more efficient than the plating method, the latter usually are not suitable for making large deposition of silver on the inner surfaces of the media. In addition, the catalysts containing coatings are more susceptible to loss of silver mechanical abrasion.

When the catalytic material is silver, the silver solution used for impregnation of the carrier preferably consists of silver compounds in a solvent or complexing/solubilizing agent, such as solutions of silver that is described in this field. Specific applicable connection silver can be selected from, for example, complexes of silver nitrate, silver oxide or silver carboxylates such as acetate, oxalate, citrate, phthalate, lactate, propionate, butyrate and silver of silver salts of higher fatty acids. The silver oxide in the de complex with amines is the preferred form of silver for use in the present invention.

For dissolution of silver to the desired concentration in the impregnating environment, you can use a large number of solvents or complexing/solubilizing agents. Among these is described agents suitable for this purpose are lactic acid (U.S. patent No. 2477436 in the name of Aries and 3501417 name DeMaio); ammonia (U.S. patent No. 2463228 in the name of West, et al.); alcohols, such as ethylene glycol (U.S. patent No. 2825701 name Endler, et al., and 3563914 name Wattimina); and amines and aqueous mixtures of amines (U.S. patent No. 2459914 on the name Schwarz; 3563914 name Wattimina; 3215750 name Benisi; 3702259 on the name Nielsen, and 4097414, 4374260 and 4321206 name Cavitt).

The amount of silver compounds, which dissolve in the solution used for impregnation of silver, usually more than the amount that ends up on the final catalyst for one impregnation. For example, Ag₂O can be dissolved in a solution of oxalic acid and Ethylenediamine to the extent of about 30 wt.%. Vacuum impregnation with a solution of the carrier of alpha-alumina with a porosity of approximately 0.7 cm³/g usually results in a catalyst containing about 25 wt.% silver calculated on the total weight of the catalyst. Accordingly, if it is desired to obtain a catalyst having a loading of silver more than about 25 or 30% or more, it is usually necessary to subject the media, at least on the mind or more successive impregnation with silver, with promoters or without promoters, up until the desired amount of silver is not deposited on the carrier. To obtain catalysts of this invention preferably employ two or more impregnations. In some cases, the concentration of silver salts is higher in the latter solutions for impregnation than in the first. For example, if the catalyst is desirable total concentration of silver is approximately 30%, a smaller amount of silver, for example, about 10 wt.%, may be precipitated on a carrier in the first impregnation and subsequent second impregnation with silver provides the deposition of the remaining 20 wt.%. In other cases, an approximately equal amount of silver precipitated during each impregnation. Often for the implementation of equal precipitation at each impregnation may be necessary that the concentration of silver in solution for subsequent impregnation was higher than the concentration in the solutions for the initial impregnation. In the following examples to the media during the initial impregnation precipitated a greater quantity of silver than the amount deposited during subsequent impregnation. For each of the impregnation may be followed by a calcination or other procedures to make the insoluble silver.

The impregnation or deposition of the catalytic material and optional promoters on the surfaces of the modified nose is the body of aluminum oxide is usually carried out in any sequence. So, impregnation and deposition of the catalytic material and the promoter can be carried out simultaneously or sequentially, i.e. one or more promoters may be deposited before, during or after addition to the medium of catalytic material. When using more than one promoter, they can be deposited simultaneously or sequentially.

Impregnation of the modified carrier of the catalytic material may be carried out using one or more solutions containing catalytic material and/or the promoter, in accordance with well known techniques for simultaneous or sequential deposition processes. In the case of a silver catalyst for co-deposition after impregnation the impregnated modified medium is heated or chemically treated for the recovery of silver compounds in metallic silver and deposition promoter on the surface of the catalyst.

For sequential deposition of the modified catalyst is first impregnated with a catalytic material or the promoter (depending on the sequence) and then heated or chemically treated, as described above. This is followed by at least a second impregnation and the corresponding heating or chemical treatment to obtain the final catalyst, terasawa silver and promoters.

After each impregnation of the modified carrier of alumina catalytic material and/or promoter impregnated carrier is separated from any remaining unabsorbed solution. This is a convenient way to perform drain excess impregnating medium or, alternatively, with the use of separation techniques such as filtration or centrifugation. The impregnated carrier is then usually subjected to heat treatment (e.g., calcined) to implement the decomposition or recovery of catalytic material, for example metal link silver (in most cases, the complexes), in the metal mold and the deposition of the promoter. Such annealing may be conducted at a temperature from about 100 degrees Celsius to about 900 degrees Celsius, preferably, from about 200 degrees to about 700 degrees Celsius, over a period of time sufficient, for example, to convert essentially the entire amount of any salts, for example salts of silver, a metal, such as metallic silver. Although this area offers a wide range of periods of heating for heat treatment of the impregnated carrier (for example, in U.S. patent No. 3563914 proposed heating for a period of not less than 300 seconds for drying, but not the annealing for the formation of the catalytic material; in U.S. patent No. 3702259 described heating from 2 to 8 hours at temperatures from 100 degrees centigrade to about 375 degrees Celsius for recovery of silver salts in the catalyst, and in U.S. patent No. 3962136 proposed heat 1/2-8 hours for the same temperature range), it is just important that the recovery time is correlated with the temperature, so that was performed essentially complete recovery, for example, salts of silver in the metal. For this purpose it is desirable to use a continuous or stepwise heating. It is preferable for the continuous annealing of catalytic material in a short period of time, for example, not longer than 1/2 hour, it can effectively conduct upon receipt of the catalysts according to this invention. When conducting more than one annealing is not necessary that the calcination conditions were the same each time the ignition.

The heat treatment may be conducted in air or you can apply an atmosphere of carbon dioxide, water vapor, nitrogen or atmosphere of other gases. The equipment used for such heat treatment, it is possible to apply an atmosphere of such gases in static conditions or in a moving stream for exercise recovery, but it is much more preferable is a moving gas stream.

Sometimes it is desirable is to avoid the use of strongly acidic or basic solutions, that can affect the modified carrier and precipitate impurities that can have a negative impact on the performance of the catalyst. The preferred method of impregnation according to the patent in the UK (which is thus included here by reference in its entirety) in combination with high temperature annealing, a technique with a short residence time, which is also described in this patent may be particularly useful in minimizing contamination of such a catalyst. The use of promoter salts in combination with carriers with high purity can afford to use lower temperatures even for short time stay.

The specific choice of solvent and/or complexing agent, a catalytic material, the conditions of heat treatment and the modified carrier of aluminum oxide may be affected in varying degrees in the size range of the particulate silver on the carrier.

In a specific example of a suitable method of impregnation of the carrier of alpha-aluminum oxide silver required amount of complexing agent such as Ethylenediamine (preferably grade with high purity), mixed with distilled water. Then to the solution at ambient temperature (approximately 23 degrees at the offer Price, SIU) under continuous stirring, slowly add the oxalic acid dihydrate (reagent grade). During this addition of oxalic acid solution temperature usually rises to approximately 40 degrees Celsius due to the exothermic reaction. Then to a solution of the salt of the diamine and oxalic acid-water while maintaining the solution temperature below about 40 degrees Celsius add a powder of silver oxide (Metz Corporation). Finally, to complete the reconstitution add monoethanolamine, aqueous solution(s) salt of an alkali metal and distilled water. The specific weight of the resulting solution is typically in the range from approximately 1.3 to 1.4 g/ml

In another example of a suitable method, the carrier is impregnated with an aqueous solution obtained by dissolving salts of silver, such as silver carbonate, silver oxalate, silver acetate, propionate, silver lactate, silver citrate, silver or neodecanoate silver, and a complexing agent, such as triethanolamine, Ethylenediamine, aminoethylamino or Propylenediamine impregnated carrier is dried and then the dried carrier is subjected to heat treatment in one or more stages or continuously with the temperature linearly varying or programmed to cause the deposition of metallic silver in the form of small particles on the external and internal surfaces of the carrier. If the salts of silver use silver nitrate, and e shall apply whether Amin, attention should be paid to ensure that the silver nitrate is present in quantities that are low enough to avoid the explosion in combination with such an amine. Except where stated otherwise, the nomenclature of the elements of groups in this description is the same as defined in the periodic table of the elements by the 1988 IUPAC nomenclature (IUPAC nomenclature of inorganic chemistry, 1960, Blackwell Publ., London). There is, for example, group IV, V, VIII, XIV and XV correspond respectively to the groups IVb, Vb, IIIa, IVa and Va of the item Deming (Chemical Rubber Company's Handbook of Chemistry & Physics, 48^thedition) and the groups IVa, Va, IIIb, IVb, Vb item IUPAK 1970 (Kirk Othmer Encyclopedia of Chemical Technology, 2^ndedition, Vol. 8, p. 94).

In this area there are a number of promoters for use in combination with specific catalytic materials and reactions. In accordance with the present invention a particularly preferred promoter is rhenium (for example, Renat-ion). When using rhenium promoter, the amount of rhenium, preferably, is in the range from about 10 to about 10000 ppm, more preferably, from about 100 to about 1000 ppm (for example, a suitable quantity of rhenium is approximately 350 ppm with modified carrier of aluminum oxide, which comprises 1-2% modifier forces the kata sodium). In many cases, further preferred is the use of a cesium promoter in addition to rhenium, as well as optional additional inclusion of cesium sulfate and/or manganese. Other suitable promoters include other alkali metals such as lithium, sodium, potassium and rubidium, and alkaline earth metals such as barium. The following examples of suitable promoters include the halides, such as fluorides and chlorides, and the oxy-anions of the elements other than oxygen having a sequence number 5-83 groups III-VII and XIII-XVII of the Periodic table (for example, one or more oxy-anions of nitrogen, sulfur, manganese, tantalum, molybdenum, tungsten and rhenium), as described in U.S. patent No. 5504053, which is hereby incorporated here by reference in its entirety. In addition, additional suitable promoters are described in U.S. patent No. 4908343 and 5057481, as well as "prior art", as described in U.S. patent No. 4908343 and 5057481, which are hereby incorporated here by reference in their entirety.

For ease of understanding the promoters are commonly referred to by terms cationic promoters, such as alkali metals and alkaline earth metals, and anionic promoters. Compounds such as the oxide of the alkali metal or of Moo₃though not as ion may turn into ionic compounds, for example, while obtaining the sludge is in the application of the catalyst. Regardless of whether this transformation, sometimes referred to here by the term cationic and anionic species, such as alkali metal or molybdate.

When the catalyst comprises rhenium promoter, rhenium component can be provided in any of various forms, for example in the form of metal, in the form covalent compounds, in the form of a cation or an anion. Examples of rhenium compounds include the halides of rhenium, oxychloride rhenium, Renata, perrhenate, rhenium oxides and acids of rhenium. In addition, you can also appropriately apply perrhenate alkali metals, perrhenate alkaline earth metals, perrhenate silver, other perrhenate and heptoxide rhenium. Heptoxide rhenium, Re₂O₇when dissolved in water hydrolyses in perrineau acid, HReO₄or perrenate hydrogen. Thus, for the purposes of this description heptoxide rhenium can be considered as perrenate, i.e. ReO₄^-. Similar chemical compounds can be represented by other metals such as molybdenum and tungsten.

As for oxyanion promoters mentioned above, in U.S. patent No. 4908343 described catalysts, in which the promoters used a mixture of at least one cesium salt and one or more salts of alkali and alkaline earth metals. the U.S. patent No. 4908343 anions of the cesium salts include oxy-anions, preferably the polyvalent oxy-anions of the elements other than oxygen having a sequence number 15-83 and members of groups 3b through 7b, inclusive, of the periodic table of elements (as published by The Chemical Rubber Company, Cleveland, Ohio, in CRC Handbook of Chemistry and Physics, 46^thEdition, on the inside back cover). In U.S. patent No. 4908343 presents salts of alkali metals and/or alkaline earth metals include at least one halide with a serial number 9-53, inclusive, and the oxy-anions of the elements other than oxygen having a sequence number either (i) 7 or (ii) 15-83, inclusive, and is selected from groups 3A-7a, inclusive, and 3b-7b, inclusive, of the periodic table of elements. Often the catalyst contains at least one anion other than oxyanion element group 3b-7b.

In U.S. patent No. 5057481 as promoters described mixture of salts of cesium, at least one of which is a salt of cesium, which has its anion is oxyanion, preferably, the polyvalent oxyanion element having a sequence number 21-75 and is a member of the group 3b-7b, inclusive, of the periodic table of elements (as published by The Chemical Rubber Company, Cleveland, Ohio, in CRC Handbook of Chemistry and Physics, 46^thEdition, on the inside back cover). Another anion or anions for cesium can be a halide and/or oxyanion elements other than oxygen is, having a sequence number either (i) 7, or (ii) 15-83 and members of groups 3b-7b, inclusive, and 3a to 7a, inclusive, of the periodic table of elements. Often the catalyst contains at least one anion, other than oxyanion element group 3b-7b. The catalyst may contain other components of the alkali metals and alkaline earth metals, which can be represented in the form of oxides, hydroxides and/or salts. As caesium containing components and components of other alkali metals and alkaline earth metals are usually used in the form of components dissolved in the solvent, may be mixed to neutralize the charges of the parts. Therefore, the catalyst obtained by the use of cesium sulfate and potassium molybdate, may also contain cesium molybdate and potassium sulfate.

Types of oxy-anions suitable as counterions for alkali and alkaline earth metals contained in the catalysts described in patent No. 4908343, or types of anions suitable as counterions for cesium contained in the catalysts described in U.S. patent No. 5057481 include as an example, sulfate, SO₄^-2, phosphates, such as RHO₄^-3manganate, for example, MnO₄^-2, titanates, such as TiO₃^-2tantalate, for example TA₂About₆^-2, molybdates, the example MoO ₄^-2, vanadates, for example, V₂O₄^-2, chromates, for example, CrO₄^-2zirconate, such as ZrO₃^-2, polyphosphates, nitrates, chlorates, bromates, wolframate, thiosulfate, Cerati or the like. The halide ions include fluoride, chloride, bromide and iodide. It is well known that many anions have a complex chemical structure and may exist in one or more forms, for example, manganate (MnO₄^-2) and permanganate (MnO₄^-1); orthovanadate and metavanadate and various molybdate the oxy-anions, such as the Moo₄^-2, Mo₇About₂₄^-2. Although oxyanion or predecessor of oxyanion can be applied in the solution used for impregnation of carriers, it is possible that under the conditions of preparation of the catalyst and/or during its application specific oxyanion or initially present predecessor can turn into another form, which can be the anion in the salt or even oxide, such as mixed oxides with other metals present in the catalyst. In many cases, analytical techniques may be insufficient for accurate identification of present species, and given the characteristics of oxyanion should not be understood as limiting the types of oxyanion, which can ultimately congregation is the substance in the catalyst during use (rather, reference oxianan is intended to provide instructions how to obtain the catalyst).

Particularly preferred anionic promoters include sulfates and oxianan rhenium, molybdenum and/or tungsten. Examples anynow sulfur that can be applied in a suitable manner, include sulfate, sulfite, bisulfite, bisulfate, sulfonate, persulfate, thiosulfate, dithionate, dithionite, halogenmethyl, for example, persulfate and so on. Preferred compounds used are ammonium sulfate and the sulfates of alkali metals. Examples of anions of molybdenum and tungsten, which can be applied in a suitable manner, include molybdate, dimolybdate, paramolybdate, other ISO - and heteropolyacids and so on and tungstate, paraformat, metabolomic, other ISO - and heteropolytungstates and so on. Preferred are sulfates, molybdates and wolframates.

Another class of promoters that can be used in the present invention include manganese components. In many cases, manganese components can increase the activity, efficiency and/or stability of the catalysts. Identification of the exact species of manganese, which provides increased activity, efficiency and/or stability, is not always reliable and this kind which may be a component added or formed either during preparation of the catalyst or during the application of the catalyst. Manganese component may be selected from manganese acetate, manganese sulfate and ammonium citrate, manganese, dithionate manganese, manganese oxalate, manganese nitrate(II), manganese sulfate(II), the permanganate anion, manganate-anion and the like. Such manganese components preferably accompanied by a complexing agent such as ethylenediaminetetraacetic acid (ETDA), which preferably is burned during subsequent calcination.

Suitable amounts of the promoter can vary widely known specialist in this field for each specific promoter.

In accordance with a specific method for impregnation of the carrier of the catalytic material and the promoter of the initial impregnation is carried out for impregnation of the carrier of the catalytic element or compound, with subsequent second impregnation, in which the carrier is impregnated simultaneously with catalytic material (element and/or compound) and one or more promoters. For example, a suitable sequence for carrying out such a pair of impregnation includes (1) vacuum impregnation of the carrier within 1-20 minutes with a solution containing 15-45 wt.% silver, preferably 25-30 wt.% silver is, moreover, the solution get (a) mixing Ethylenediamine (grade high purity) with distilled water, (b) by slow addition of oxalic acid dihydrate (reagent grade) to aqueous solution of ethylene diamine in environmental conditions, resulting in an exothermic reaction and the temperature of the solution increased to approximately 40 degrees Celsius (C) by slow addition of silver oxide and (d) the addition of monoethanolamine (not containing Fe and Cl); then (2) remove excess solution impregnation; then (3) optional washing impregnated with silver media solution, which is same as the above solution for impregnation of silver, except that it does not contain silver oxide or monoethanolamine, i.e. a solution of Ethylenediamine, water and oxalic acid, to reduce the number of large (occlusive) of silver particles on the external surface of the catalyst, which can sometimes occur during annealing; (4) remove excess rinse solution through the outlet shutoff valve tube for impregnation for about 2-10 minutes, preferably about 5 minutes, then (5) calcining the impregnated silver media in hot air using a belt furnace for firing approximately at 400-600 degrees Celsius, preferably, when listello at 500 degrees Celsius, for about 1-10 minutes, preferably about 2.5 minutes with a stream of air is approximately 40-90 standard cubic feet per hour (SCFH)/in²preferably, about 66 cubic feet per hour/inch²; then (6) vacuum-impregnated impregnated with silver media solution for the second impregnation containing silver and promoters within 1-20 minutes, and the solution for the second impregnation received (a) mixing Ethylenediamine (grade high purity) with distilled water; (b) by slow addition of oxalic acid dihydrate (reagent grade) to aqueous solution of ethylene diamine in environmental conditions, resulting is an exothermic reaction and the temperature of the solution increased to approximately 40 degrees Celsius (C) by slow addition of silver oxide, (d) the addition of monoethanolamine (not containing Fe and Cl), (e) adding one or more promoters and (NH₄)₂H₂(Edtc); (7) then remove excess solution impregnation, then (8) optionally rinsing the impregnated silver and promoter of the carrier solution, which is the same as the above solution for the second impregnation, except that it does not contain silver oxide, i.e. a solution of Ethylenediamine, monoethanolamine, optional promoter, optional(NH ₄)₂H₂(Edtc), water and oxalic acid; (9) remove excess rinse solution through the outlet shutoff valve tube for impregnation for about 2-10 minutes, preferably about 5 minutes, and then (10) calcining the impregnated silver and promoter of the media in hot air using a belt furnace for firing at approximately 400 to 600 degrees centigrade, preferably at about 500 degrees Celsius, for about 1-10 minutes, preferably about 2.5 minutes and with a flow of air 40-90 SCFH/inch²preferably, approximately 66 SCFH/inch².

As mentioned above, the carriers of the present invention are particularly suitable for use in preparation of the epoxide of alkylene vapor-phase epoxydecane corresponding alkylene, especially ethylene, molecular oxygen and/or one or more other oxygen-containing compounds. Reaction conditions for the reaction of epoxidation are well known and extensively described in the prior art. It refers to the reaction conditions, such as temperature, pressure, residence time, concentration of reactants, gaseous diluents (e.g., nitrogen, methane and CO₂), gas-phase inhibitors (for example, ethylchloride, vinyl chloride and ethylene dichloride), d is the additives and/or gaseous promoters (for example, the promoters described by Law et al. in U.S. patent No. 2279469 and 2279470, such as nitrogen oxides and compounds generating nitrogen oxides, one or more gaseous efficiency-enhancing member of the redox pair of half-reactions (see U.S. patent No. 5504053, which is thus incorporated herein by reference in its entirety) or the like. Epoxidation of ethylene is a highly exothermic reaction and the heat of reaction for the combustion of ethylene by conversion of CO₂and H₂About twelve times higher than the heat of formation of ethylene epoxide. Fast and efficient removal of heat of reaction from the catalyst and the gas phase is extremely important, since otherwise further oxidation of ethylene epoxide will accelerate, leading to a reduced selectivity.

The promoters for the catalyst used in the present invention may also be of the type that includes at least one efficiency-enhancing salt of a member of the redox pair of half-reactions, which are used in the epoxidation reaction in the presence of a gaseous component capable of forming a gaseous efficiency-enhancing member of a pair of redox of polyreactive under the reaction conditions. The term "redox polyreactive" is used here on the I denote the half-reactions, like the half-reactions detected in the equations presented in the tables of standard potentials recovery or oxidation, also known as standard or individual electrode potentials of the type specified, for example, in “Handbook of Chemistry”, N.A. Lange, Editor, McGraw-Hill Book Company, Inc., pages 1213-1218 (1961) or “CRC Handbook of Chemistry and Physics”, 65^thEdition, CRC Press, Inc., Boca Raton, Fla., pages D155-162 (1984). The term "redox pair of half-reactions" refers to a pair of atoms, molecules or ions or their mixtures that undergo oxidation or restoration in these equations half-reactions. Terms such as redox pair of half-reactions, is used here in such a way that they include members of this class of substances, which provide the desired improvement in performance, and no mechanism occurring chemical reactions. Preferably, such compounds, when they are associated with the catalyst in the form of salts of the members of a pair of half-reactions are salts in which the anion is the oxy-anions, preferably, oxyanion polyvalent atom, i.e. an atom of the anion is bound oxygen that can exist when it is associated with a different atom, in different valence States. Used here, the term "salt" does not mean that the anionic and cationic components is s salt associated or bound to the solid catalyst, but only means that both components are present in some form in the catalyst under the reaction conditions. Potassium is the preferred cation, although sodium, rhodium and cesium may also be suitable cations, and the preferred anions are nitrate, nitrite and other anions can undergo substitution or other chemical reaction to form the nitrate anions in the conditions of the epoxidation. Preferred salts include KNO₃and KNO₂and KNO₃is the most preferred.

Salt of a member of the redox pair of half-reactions are added to the catalyst in a quantity sufficient to increase the efficiency of the epoxidation reaction. The exact number will vary depending on variables such as the use of gaseous efficiency-enhancing member of a redox of polyreactive and its concentration, the concentration of other components in the gas phase, the amount of silver contained in the catalyst, the surface area of the substrate, the process conditions, such as space velocity and temperature, and morphology of the substrate. In the alternative case, it may be added a suitable connection predecessor, so that the required number of member of the redox pair of half-reactions were formed in the catalysis of the Torah in the conditions of epoxidation, especially by reaction with one or more components of gas-phase reactions. Typically, however, a suitable concentration range of added efficiency-enhancing salt or its predecessor, based on the cation is from about 0.01 to about 5 weight percent, preferably, from about 0.02 to about 3 weight percent, based on the total weight of the catalyst. Most preferably, the salt is added in amount of from about 0.03 to about 2 weight percent.

The preferred gaseous efficiency-enhancing member of the redox pair of half-reactions are compounds containing the element can exist in more than two valence States, preferably nitrogen, and another element, which is preferably oxygen. Gaseous component capable of forming a member of the redox pair of half-reactions under the reaction conditions, usually a nitrogen-containing gas, such as, for example, nitric oxide, nitrogen dioxide and/or dinitrogen tetroxide, hydrazine, hydroxylamine or ammonia, nitroparaffin having 1-4 carbon atoms (for example, nitromethane), reduction of the compound (especially, nitrobenzene) and/or N-nitro compounds, NITRILES (e.g. acetonitrile). The number ATTS is holding a gaseous promoter, which is used in these catalysts, is a quantity sufficient to enhance performance, such as catalyst activity and especially the effectiveness of the catalyst. The concentration of nitrogen-containing, gaseous promoter is determined by the specific efficiency-enhancing salt of a member of the applied redox pair of half-reactions and concentration, especially under oxidation of alkene, and other factors, including the amount of carbon dioxide in the reaction gases at the outlet. For example, in U.S. patent 5504053 described that when the nitrogen-containing gaseous promoter is NO (nitric oxide), a suitable concentration is from about 0.1 to about 100 volume ppm in the gas stream.

Although in some cases it is preferable to use members of the same pair of half-reactions, that is, as increasing the efficiency of the promoter in the form of salts associated with the catalyst and gaseous promoter member of the feed stream, as for example, a preferred combination of potassium nitrate and nitric oxide, this is not necessary in all cases to achieve satisfactory results. In the same system can also use other combinations, such as KNO₂/N₂O₃, KNO /NO₂, KNO₃/N₂O₄, KNO₂/NO, KNO₂/NO₂. In some cases, salt and gaseous States can be found in different half-reactions, which represent the first and last reactions in a series of equations of the half-reactions common reaction.

In any case, solid and/or gaseous promoters presented in the promoting amount. Used here, the term "promoting amount" of some component of the catalyst refers to the amount of the component that operates efficiently, providing an improvement in one or more catalytic properties of this catalyst compared to a catalyst not containing the specified component. Examples of catalytic properties include, inter alia, the suitability (resistance to unmanaged mode), selectivity, activity, conversion, stability and output. The person skilled in the art it is clear that one or more separate catalytic properties can be improved "promoting amount", while other catalytic properties may be or may not be improved or can be even worse. It is clear then that the different catalytic properties can be improved at different operating conditions. For example, a catalyst having high selectivity under one set of operating conditions, outdistance with a different set of working conditions in which the improvement is manifested in the activity, not in selectivity, and the operator of the receipt of ethylene oxide intentionally alters working conditions in order to benefit in some catalytic properties even at the expense of other catalytic properties to maximize profits taking into account the cost of raw materials, energy costs, the cost of removal of by-products and the like.

On the promoting effect provided by the promoters may be affected by several parameters, such as, for example, reaction conditions, methods of preparation of the catalyst, the surface area and pore structure and chemical properties of the surface of the substrate, the silver and the concentration of other promoters present in the catalyst, and the presence of other cations and anions in the catalyst. The presence of other activators, stabilizers, promoters, enhancers or other means to improve the properties of the catalyst can also affect the promoting action.

The desirability of recycling unreacted raw materials or application of the single-pass system, or application of sequential reactions to increase the conversion of ethylene through the use of reactors arranged in series, can be easily determined by the person skilled in the art. The specific method selected operation usually dickcheesecake method.

The present invention is applicable to reactions epoxidation in any suitable reactor, such as reactor with fixed bed, fluidized bed reactor, a wide variety of which are well known to the person skilled in the art and do not need detailed description here.

The conversion of ethylene to ethylene oxide can be, for example, continuous introduction of a flow of the raw material containing ethylene and oxygen, containing a catalyst of the reactor at a temperature of from about 200 degrees Celsius to about 300 degrees Celsius and the pressure may range from about 5 atmospheres to about 30 atmospheres, depending on the desired mass flow and performance. The time of stay of the reactants in the reactors on a large scale is typically of the order of approximately 0.1-5 seconds. The oxygen can be fed into the reactor in an oxygen-containing stream such as air or commercial oxygen or oxygen-enriched air. The resulting ethylene oxide is separated and recovered from the reaction products using conventional methods.

The catalysts described here can be applied to widely changing process conditions, which are well known to the person skilled in the art. However, in order to determine the standard which the shaft of the sets of conditions, to compare the activity, efficacy, stability and other factors, obtained with a specific catalyst, a standard set of process conditions, referred to here as "the Standard conditions of the epoxidation of ethylene", is determined as follows.

CONDITIONS of the METHOD of EPOXIDATION of ETHYLENE

For testing of the catalyst used standard autoclave with a reverse mixing and internal gas recirculation or single-pass tubular reactor. There is some variation of the concentrations in the raw material is ethylene, oxygen, and gas-phase modifier/promoter depending on the applied conditions. Illustrated by two cases: method using air, which simulate typical conditions used in commercial ways epoxidation of ethylene with the use of air, where the air is used to supply molecular oxygen, and the conditions of the method using oxygen, which simulate typical conditions in the commercial methods of epoxidation of ethylene with oxygen as the oxygen source add pure oxygen. Each case provides a different efficiency, but there is a rule for almost all cases, when using air as the oxygen raw material, smaller quantities of oxygen and ethylene e is the efficiency of conversion to ethylene oxide of about 2-5 percentage points lower than the efficiency of transformation, when the source of oxygen used pure oxygen. As one of the types of reactors used are well known autoclaves “Magnedrive” reverse stirring until the bottom is described in Fig. 2 article J.M. erty, entitled “Reactor for Vapor Phase Catalytic Studies”, in Chemical Engineering Progress, Vol. 70, No. 5, pages 78-84, 1974. Conditions at the inlet are as follows.

The pressure to maintain a constant at approximately 200-275 lbs/square inch and the total flow at the outlet support at approximately 11,3 or 22.6 SCFH. SCFH refers to cubic feet per hour at standard temperature and pressure, namely, at 0°C and one atmosphere. is oncentration of ethylchloride adjusted to maintain maximum efficiency. Temperature (°C) and the catalytic efficiency is usually obtained as the parameters describing the performance characteristics of the catalyst. Testing method of the catalyst used for autoclaves in terms of the way the epoxidation of ethylene, is as follows: 40 or 80 cm³the catalyst is loaded into the autoclave with a reverse mixing and mass of catalyst record. Autoclave with reverse stirring is heated to approximately the reaction temperature in a stream of nitrogen 10-20 SCFH with fan operating at 1500 rpm Then the flow of nitrogen is interrupted and the reactor enter the flow of the above-described raw materials. The total flow of gas from the outlet to regulate 11,3 or 22.6 SCFH. Temperature regulate over the next few hours to ensure an adequate flow of ethylene oxide in the outlet. Optimum efficiency can be obtained by regulation of the content of ethylchloride. Monitor the concentration of epoxide at the outlet to verify that the catalyst has reached its peak performance under steady-state conditions. The concentration of ethylchloride can periodically be adjusted, and thereby achieving the effectiveness of the catalyst for the formation of ethylene oxide and an acceptable rate of deactivation (on ysenia temperature and/or efficiency loss).

Testing method of the catalyst used for the tubular reactor in terms of the way the epoxidation of ethylene, is as follows: approximately 5 g of the catalyst is crushed in a mortar with a pestle, then sieved standard sieves USA with 30/50 mesh. 0.5 g of the sifted material is loaded into the micro-reactor with an inner diameter of 25 inches, made of stainless steel (wall thickness 0,0035 inches). To maintain the catalyst used in place of glass wool. The reaction tube is installed in a heated brass block, which is placed in front of him thermocouple. The unit is enclosed in an insulated casing. Gaseous feedstock is passed over the heated catalyst at a pressure of 200 pounds per square inch. The flow reactor regulate and register at standard pressure and room temperature.

The standard deviation of a single test result, which gives the efficiency of the catalyst in accordance with the techniques described above, is approximately 0.5% of the units efficiency. A typical standard deviation of a single test result representing the activity of the catalyst in accordance with the methodology described above, is approximately 2°C. the Standard deviation, of course, will depend on the quality of equipment and accuracy of the methods used in testing, and thus, will be changed. It is believed that the test results reported here are within the standard deviation, above.

In determining the activity and efficiency of the process and the catalyst should be in the steady state equilibrium. They can often be quickly identified the achievement of steady state equilibrium.

Properties of the starting materials of the carrier and the specifics of their modifications are detailed in table II. In table III are given the specifics of washing some modified media. In table IV are given the specificity of the obtained catalyst media, including the compositions of the catalysts.

Receiving the MODIFIED MEDIA

Some of the α-alumina impregnated under vacuum with a solution of silicate of alkaline metal (see table II). The solution of alkali metal silicate added to the vessel of glass or stainless steel, which is provided with suitable shut-off valves for impregnation of the carrier in a vacuum. A suitable separating funnel containing impregnating solution, is inserted through a rubber stopper in the upper part of the vessel for impregnation. The air from the vessel for impregnation containing the medium is pumped to approximately the pressure of 1-2 inches of mercury (absolute pressure) for 10-30 minutes, after which the impregnating solution honey is i.i.d. add to the media by opening a shut-off valve between a separating funnel and the vessel for impregnation. After the entire solution will be poured into a vessel for impregnation (~15 seconds), the vacuum is removed and the pressure returns to atmospheric. After adding a solution of the carrier remains immersed in the impregnating solution at ambient conditions for 10-30 minutes and then the excess solution is drained within 10-30 minutes.

The impregnated carrier is dried by placing it in a single layer on a wire mesh support made of stainless steel, which are then placed in a drying Cabinet. Apply modes raise the temperature to slow the drying of the impregnated carriers (see table II). After drying Cabinet off and the door open, so that rapid cooling or, in some cases, the samples are left to cool over night. Alternatively, drying the impregnated carrier at equivalent conditions apply drying Cabinet with adjustable humidity (see table II).

Soaked and dried carrier then calicivirus in one or more ceramic trays which are placed in a high temperature electric furnace and subjected to heat treatment (data in table II). The temperature is slowly increased to the maximum temperature of the annealing, which is supported within two to four hours. After completion of the temperature regime oven off. In some cases, the door from the current so to begin rapid cooling. The resulting carrier weigh and calculate the loading of the alkali metal silicate (results are given in table II). Alternatively, use the equipment for a large scale to obtain large quantities of media, and media calcined in a tunnel kiln with gas heating when programming equivalent temperature.

WASHING MODIFIED MEDIA

For washing the modified media used several methods. In the first of the formed carrier is divided in half and placed in two Soxhlet extraction apparatus 40 cm³so as not to exceed the limits of coverage for them (see table III). The top of each extractor connect with having open ends water condensers with a round glass fittings, which wrap Teflon tape. Extractors and condensers then fix three finger clamps that are located in the formed compounds. Then 100 ml of deionized water is added in two weighted round-bottom flask, which is then combined with the lower parts of extractors with a round glass fittings, which also wrap Teflon tape. Then the capacitors are filled and washed with slow steady stream of water that flows into the lower hole capacitors, viteee is from the top. United extractors then lowered until, while round-bottom flask will not be suitable heating jackets. The open top of the flasks and the lower 2/3 of the extractors then wrap with aluminum foil. Then heating the casing to regulate until the water begins to boil, and then heating support to provide fixed (every 5 seconds) falling drops from the top of the capacitors. In the cycle of washing time required for the water level inside the extractor has exceeded the capacity of the fill, resulting in a then activates the process siphonaria, which drains water from the extractor through a tube of siphonaria, takes each time about 15 minutes or 4 times per hour. After a time of 12 hours or ~48 wash cycles the heating stop disconnecting the energy source and lifting equipment of the heating panels. Water current in the capacitors, then block after the water inside round-bottom flasks ceases to boil.

The flask and its contents are collected and weighed. Extractors then disconnect from the capacitors and wet media were removed and weighed. Then wet the medium is transferred into a two wire mesh stand stainless steel 4×22×1 cm and dried in a drying Cabinet for ~3 hours at 110°C. After sociopathic washed and dried carrier weigh and calculate the change in mass media (see table III).

When the second flush processing calcined modified carrier impregnated under vacuum with a solution obtained by mixing 250 g of distilled water, 259 g of Ethylenediamine, 259 g of dihydrate of oxalic acid, 95 g of monoethanolamine and additional 423 g of distilled water. The carrier impregnated in a vacuum (absolute pressure 1-2 inches of mercury) solution by the method identical to the method specified upon receipt of the modified media. After the descent of the water carrier calcined in air. It spread in a single layer on two wire mesh mats stainless steel, then placed on a steel mesh belt and transported through the heating zone with the area of 2” × 2” for 2.5 minutes. The heating zone is maintained at 500°C. by passing hot air upward through the belt and around the particles of the medium at the speed of 266 standard cubic feet per hour (SCFH). After calcinations at zone heating the washed carrier is cooled in open air at room temperature. In the third leaching processing the modified carrier impregnated in a vacuum with distilled water at room temperature. Water-soaked media is placed in a ceramic Cup in 1-2 layer and dried in a vacuum drying Cabinet established at an absolute pressure of 9 inches of mercury, for four cha is impressive. The whole process is repeated more than two times using each time a new water solutions.

Preparation of CATALYSTS

The resulting media impregnated in vacuum (see tab. IV) a first solution of silver to seal, usually containing 30 wt.% silver oxide, 18 wt.% oxalic acid, 17 wt.% Ethylenediamine, 6 wt.% of monoethanolamine and 27 wt.% of distilled water. The first solution for impregnation receive (1) mixing of 1.14 parts of Ethylenediamine (grade high purity) from 1.75 parts of distilled water; (2) by slow addition of 1.16 parts of the dihydrate of oxalic acid (analytical grade) to aqueous solution of ethylene diamine so that the solution temperature did not exceed 40°C, (3) by slow addition of 1.98 parts of silver oxide and (4) the addition of 0.40 parts of monoethanolamine (not containing Fe and Cl).

The carrier impregnated in the glass and the steel cylindrical vessel of suitable size, which is provided with suitable shut-off valves for impregnation of the carrier in a vacuum. A suitable separating funnel, which is used to accommodate the impregnating solution, is inserted through a rubber stopper in the top of the vessel for impregnation. The air from the vessel for impregnation containing the medium pumped approximately to an absolute pressure of 1-2” Hg for 10-30 minutes, after which the impregnating solution is added slowly to the media by opening a shut-off valve between a separating funnel and the vessel for impregnation. The specific compositions of the solutions are given in table IV. After the introduction of the entire solution in the vessel for impregnation (~15 seconds), the vacuum is removed and the pressure returns to atmospheric. After adding a solution of the carrier remains immersed in the impregnating solution at ambient conditions for 5-30 minutes, and then excess solution is drained within 10-30 minutes.

Impregnated with silver media is then calcined as described below, to effect the recovery of silver on the catalytic surface. The impregnated carrier is distributed in a single layer on wire mesh racks stainless steel, then placed on a stainless steel belt (spiral weave) and transported through the heating zone with the area of 2” × 2” for 2.5 minutes or apply equivalent conditions for the operations on the larger ribbon. In the area of the heating support 500°C. by passing hot air upward through the belt and around the catalyst particles at a speed of 266 standard cubic feet per hour (SCFH). After annealing in the heating zone, the catalyst is cooled in open air at room temperature and weighed (the results are given in table IV).

Then impregnated with silver carrier impregnated in a vacuum with a second solution of silver for impregnation containing a solution of silver oxalate and amine, and catalyst promoters. The second solution for impregnation consists of just drained solution from the first impregnation plus fresh aliquot of the first solution, or apply a new solution. The promoters, either in aqueous solution or undiluted add (in ascending number order shown in table IV) with stirring.

Stage impregnation, washing and calcination for the specified second impregnation is conducted similar to the first soaking.

Double-saturated media, i.e. the final catalyst, weighed again and the weight gain of the carrier in the second impregnation calculate wt.% silver and the concentration of the promoters (the results are given in table IV). The final catalyst was then used in the reaction of epoxidation of ethylene, the results of which are listed in tables V, VI, VII and VIII.

EXAMPLES 1-5

In examples 1-5 the catalysts of rooms 1-5 feel under the conditions listed in table I to show the effect of various modifications subsequent processing media on the activity, efficiency and durability of the catalyst. Comparative catalyst 2 was not subjected to the addition of the silicate of an alkali metal or washing.

EXAMPLE 6

Half gram of catalyst 6, which received the treated sodium silicate wear is hardly without washing, experienced in the microreactor in the conditions of the first method with the use of air are given in table I. At a constant content of ethylene oxide in the outlet openings of 1.40 mol.% the initial selectivity of the catalyst 6 was 79,2%, but increased up to a maximum of an 80.2% after receiving the catalyst 20000 SW pounds per cubic foot of catalyst (measured for all granules). The initial temperature was 258°C, but decreased to 254°C after receiving 5000 SW pounds per cubic foot of catalyst. The temperature was 256°C at maximum efficiency. After receiving 25000 pounds EO number ethane feedstock was reduced to zero and the contents of ethylchloride reduced to 1.2 h/million under these conditions, the efficiency decreased from an 80.2 to 79,9% and the temperature was increased from 263°to 264°C, when the catalyst is formed from 25000 to 45000 SW pounds per cubic foot of catalyst.

EXAMPLE 7-8

Catalyst 7 was received on the washed modified media G. Comparative catalyst 8 was obtained analogously to catalyst 7, except that the medium is not modified sodium silicate. Table VI summarizes the performance characteristics of the catalyst of the way with the content of the SW at the outlet of 1.4% in the II with the use of air specified in table I.

EXAMPLES 9-11

In table VII compares the initial operational characteristics of the catalysts in conditions 9-11-II method with the use of air at constant content of ethylene oxide in the outlet of 1.4 mol.%. The catalyst was 9 not processed by leaching, but is included here for comparison with the catalyst, which were subjected to leaching. The results are shown after a few days of surgery or after getting around is about 2000 SW pounds/cubic foot of catalyst.

EXAMPLES 12-14

In table VIII compares the operating characteristics of the catalysts 12-14 in terms of the third way of using air in the EO content at the outlet of 1.4 mol.%. Comparative catalyst 14 was received on the media, which was not subjected to modification by sodium silicate.

1. The method of obtaining modified carrier for a catalyst, which is used for vapor-phase epoxidation of alkene, including:
a) impregnation of a pre-molded carrier of alpha-alumina, which was subjected to annealing and, optionally, other provide preliminary molding processing as part of the process of pre-forming at least one modifier selected from alkali metal silicates and alkaline earth metal silicates;
b) drying the specified impregnated is osites and
c) annealing the dried specified carrier at a temperature of at least 800°C.

2. The method according to claim 1, where the specified modifier selected from the group consisting of sodium silicates, lithium silicates and potassium silicates, or mixtures thereof.

3. The method according to claim 1, where the specified modifier is sodium silicate with a stoichiometry of Na₂O-2,6 SiO₂.

4. The method according to claim 1, where the specified drying is carried out at a temperature not exceeding about 250°C., for at least the first two hours after this treatment.

5. The method of preparation of the catalyst, which is used for vapor-phase epoxidation of alkene, including:
a) impregnation of a pre-molded carrier of alpha-alumina, which was subjected to annealing and, optionally, other provide preliminary molding processing as part of the process of pre-forming at least one modifier selected from alkali metal silicates and alkaline earth metal silicates;
b) drying the specified saturated media,
c) annealing the dried specified carrier at a temperature of at least 800°C and
d) deposition of silver catalytic material is dried to the specified media.

6. The method according to claim 5, where at least one efficiency-enhancing promoter OS is to promote specified, pre-formed alpha-alumina.

7. The method according to claim 6, where the specified increase the efficiency of a promoter selected from the group consisting of at least one alkali metal, alkaline earth metal or oxyanion element other than oxygen having a sequence number 5-83 and selected from groups 3b-7b and 3A-7a of the Periodic table.

8. The method according to claim 6, where the specified increase the efficiency of the promoter is a salt of a member of a pair of redox half-reactions.

9. The method according to claim 6, where the specified increase the efficiency of the promoter is rhenium component.

10. The method according to claim 1 or 5, where the specified alkene is ethylene.

11. The modified carrier for catalyst, which is used for vapor-phase epoxidation of alkene obtained by the method, which includes:
a) impregnation of a pre-molded carrier of alpha-alumina, which was subjected to annealing and, optionally, other provide preliminary molding processing as part of the process of pre-forming at least one modifier selected from alkali metal silicates and alkaline earth metal silicates;
b) drying the specified impregnated carrier, and
c) annealing the dried specified carrier at a temperature, less than the least 800°C.

12. The catalyst, which is used for vapor-phase epoxidation of alkene obtained by the method, which includes:
a) impregnation of a pre-molded carrier of alpha-alumina, which was subjected to annealing and, optionally, other provide preliminary molding processing as part of the process of pre-forming at least one modifier selected from alkali metal silicates and alkaline earth metal silicates;
b) drying the specified saturated media,
c) annealing the dried specified carrier at a temperature of at least 800°C and
d) deposition of silver catalytic material is dried to the specified media.

13. The method according to claim 1, where the pre-molded carrier of alpha alumina includes fluoride-containing alumina plate type having at least 95 wt.% alpha-aluminum oxide, the unique morphology of the mating plates and surface area of at least approximately 0.5 m²/g, pore volume of at least approximately 0.5 cm³/g and an average pore diameter of from about 1 to 25 microns.

14. The method according to item 13, where the modifier is sodium silicate with a stoichiometry of Na₂O-2,6 SiO₂.

15. The method according to claim 1 or 13, where the specified modificirowan the th carrier is washed after the annealing.