Method of removing an ionisable particles from the surface of the catalyst to improve catalytic properties

 

(57) Abstract:

The invention relates to the field of catalysts carriers. Described is a method of obtaining a catalyst with improved catalytic properties, while the above-mentioned method includes a selection of media, reducing the concentration inisheer particles on the surface of the media, and the application of a catalytically effective amount of one or more catalytically active metals to the media. The described catalyst made according to this method, and describes the use of such catalysts in the way epoxidation of alkenes. In the examples, the concentration reduction inisheer particles obtained by washing the carrier of alpha-aluminum oxide boiling water. After that, the dried carrier is impregnated with the promoter and silver. Technical result: the resulting catalyst has a number of improved catalytic properties, namely, selectivity, activity and stability. 3 N. and 7 C.p. f-crystals, 3 tables.

The scope of the invention

The invention relates to a method for producing a catalyst with improved catalytic properties.

The background to the invention

The presence of some of the mini metals and/or operation of the catalyst and is usually believed to the concentration of these harmful particles must be controlled throughout the mass media. One way of controlling the amount of impurities in the mass, though expensive, is to use pure starting materials. For example, in U.S. patent No. 4797270 described washing water to reduce the content of sodium in the alumina powder. For the extraction of other metals may require the establishment pH of wash water and in Japanese patent JP56164013 described the use of low pH (acid) for the extraction of uranium and thorium from raw materials calcined-alumina.

Several methods in the art indicates that it is useful rinse after deposition of the catalytic metal. In U.S. patent No. 4361504 and 4366092 offered to wash the catalyst for ethylene oxide with water after application to the carrier of the silver or silver/gold. In European patent application EP-A 211521 described washing of the catalyst with hot water to remove the main substances remaining on the catalyst from the process of impregnation with silver, or physical deposition of alkali metals. In U.S. patent No. 4367167 described a method of obtaining a catalyst on the carrier, in which the impregnated carrier is immersed in an inert not smesi the U.S. No. 4810689 described the application of silver compounds, the decomposition of this compound silver to silver in the presence of compounds of alkali metal, removal of organic deposits by washing and the introduction of fresh alkali metal impregnation during or after the stage of washing.

In the description of the patent of great Britain No. 568978 described a method of producing aluminum oxide high stability and resistance to destruction, which includes the deposition of an aqueous alumina, thermal aging that precipitate at temperatures above 125°F (51,5°C) for stabilization of alumina, washing alumina, grinding, molding pieces and heat treatment of the molded pieces in the range from 1000 to 1600°F (537,8-871,1°C), whereby the said pieces when they are granules of a diameter of 4 mm, and have a hardness defined by a blade component, at least 3500 grams.

In U.S. patent No. 4994587 described method of epoxidation of alkene comprising contacting the alkene and oxygen-containing gas in the presence of at least one efficiency-enhancing gaseous member of a pair of redox half-reactions selected from the group consisting of NO, NO2N2ABOUT3and N2O< the efficiency of nitrate salt of a member of a pair of redox half-reactions, on the media of solid alpha-alumina containing less than about 50 hours per million (ppm), and preferably less than 20 hours per million leached sodium. In addition, this document establishes a link between the requirement for a relatively low sodium content and a specific redox reaction pair, claiming that in other cases, the presence of leachable sodium in a silver catalyst improves the efficiency of the system commonly used in the epoxidation conditions.

In U.S. patent No. 4186106 and 4125480 described washing with an inert fluid after application of catalytic metal and before application of the promoting agent.

In U.S. patent No. 4908343 indicated that it may be desirable to remove the cations which can be exchanged with alkali and alkaline earth metals contained in the solution used for impregnation, in order to provide for ease of repeatability in the use and re-use solution for impregnation. For such removal does not specify any methods, however, in the art it is well known that acids are highly effective solutions for the removal of cations.

Development of water remove impurities usually consisted impact on the device itself. It was found that the deposition of metal and/or catalytic properties of the catalyst can be substantially improved by controlling the surface smoothness of the medium, not the cleanliness of the entire mass media, so that the total number of impurities may actually be large as long as the number of impurities on the surface of the support at a low level.

Brief description of the invention

In accordance with one method embodiment of the invention provides a method of improving the properties of the catalyst carrier by processing, when this treatment is carried out on one or more substances, of which receive the media, and/or on the finished media while this treatment is effective to reduce the concentration of one or more inisheer particles on the surface of the carrier, and this reduction is expressed as a reduction of at least 5 percent relative concentration of Na atoms and/or Si, which is determined by x-ray photoelectron spectroscopy (RFS), conducted on raw and processed media.

Some of the RFU concentration of Na on the surface of the carrier reduce at least 5% and/or concentric the El was reduced, at least 40% and/or the concentration of Si was reduced at least by 10%.

Optional processing to reduce the concentration is accompanied by a stage of drying.

In addition, provided is a method of obtaining a catalyst, particularly a catalyst for the epoxidation of olefins, when applying a catalytically effective amount of one or more catalytically active metals and, optionally, one or more promoting substances on the carrier obtained in a certain way.

Also provided is another way catalytic epoxidation of alkene oxygen-containing gas in the gas phase using a catalyst obtained defined above.

Description of preferred embodiments

It was found that media that has been processed to reduce some unwanted inisheer particles, in particular anionic particles on the surface of the media, provide catalysts with improved catalytic properties compared to the performance of catalysts made from carriers that have not been processed in this way. I believe that this method is spacebase substance carrier, compared with the catalyst made from the raw media. In addition, this method applies to both organic and inorganic carriers.

The method is effective for improving at least one of the catalytic properties of the catalyst in which the catalytically active metal is applied, or which is saturated media containing on its surface Ionithermie particles. “The improvement in the catalytic properties”, as used here, means that the properties of the catalyst are improved compared with the catalyst, obtained from the same media that has not been processed to reduce the amount of surface inisheer particles. The catalytic properties of the mean activity of the catalyst, the selectivity characteristic of the activity and/or selectivity over time, performance (resistance to being out of control), conversion and speed.

For the method it is necessary that the concentration of undesirable inisheer particles on the carrier surface has been reduced. As used here, the “surface” of the media represents the area of the carrier which can be measured in the standard way of Brunauer, Emmett and Teldat reaction. “Insueta” particle is a particle that can be translated in the ionic state, where the term “ion”, or “ion” refers to an electrically charged chemical group.

The rate of solubilization of the silicates may be determined by the method of inductively coupled plasma (ICP), and the number of particles of sodium and silicon on the surface can be determined by x-ray photoelectron spectroscopy (RFS). In determining the present invention the amount of sodium and/or silicon on the surface of the carrier, some of the fur, before and after treatment according to the invention, were selected as indicator quantities inisheer particles. To determine changes in the conductivity of the solution used for another measurement method.

Typically, the carriers are inorganic substances, such as compounds based on aluminum oxide, silicon dioxide or titanium dioxide, or their combinations, such as media based on aluminum oxide-silicon dioxide. The media can also be obtained from compounds based on carbon, such as charcoal, activated carbon or fullerenes.

Ionithermie particles, usually located on volumetrical, cesium, lithium, and combinations thereof. Of particular interest Ionithermie anionic particles on the surface, in particular Ionithermie silicates. The decrease in the concentration inisheer particles can be accomplished by any method effective to (i) transfer inisheer particles in the ionic state and the removal of these particles, or (ii) transfer inisheer particles in the insoluble state, or (iii) transfer inisheer particles in a stationary state. However, the use of aggressive media undesirable because these environments tend to dissolve the medium to extract too much of the substance of mass and generate acidic or basic sites in the pores. Acid, which, among other things, are aggressive environments, remove the cations from the media, but they are quite ineffective for removing unwanted anions, such as silicates. Effective ways to reduce concentrations include washing media, ion exchange, evaporation, precipitation or binding of impurities in the complex, carrying out the reaction for translation inisheer particles on the surface in the insoluble state, and combinations thereof. Examples of solutions for washing and ion exchange include solutions based on water and/or organic rastriya, acetate strontium, crown ether, methanol, ethanol, dimethylformamide and mixtures thereof.

You ready to handle the media or can be processed to be used to obtain carrier substances before receiving media. In addition, when the processing of materials for the media prior to the manufacture of media there are still big improvements in the processing of the surface of the media. The carrier may be dried after the reconstruction processing of an ionisable particles.

For the manufacture of the catalyst from the carrier this carrier is usually impregnate compound(s), complex(s) and/or salt (salts) of the metal dissolved in a suitable solvent, which is effective for coating or impregnation of the carrier of a catalytically effective amount of metal. As used here, “catalytically effective amount” means the amount of metal that will provide measurable catalytic effect. For example, in relation to the catalyst for the epoxidation of olefins catalytically effective amount of metal is such a quantity of metal, which will provide measurable conversion of the olefin and oxygen in the oxide alkylene.

Further improvements in the properties of the catalyst on the activity of hydrogen ions which are reduced. “The activity of hydrogen ions”, as used here, represents the activity of hydrogen ions, as measured by the potential of the hydrogen ion-selective electrode. As used here, the solution with “low” activity of hydrogen ions refers to the solution, the activity of hydrogen ions which changed when adding the substrate so that the activity of hydrogen ions this modified solution is reduced in comparison with the activity of hydrogen ions in the same solution in an unmodified state. The basis chosen for changes of the solution, you can choose from any of the base or connection with the PKbless than the initial solution for impregnation. Especially, it is desirable to choose a Foundation that does not change the composition of the solution used for impregnation, that is, which does not alter the desirable concentration of metals in the solution for impregnation and supported on a carrier. Will not change the concentration of metals in the solution used for impregnation of an organic base, examples of which include hydroxides of tetraalkylammonium and 1,8-bis(dimethylamino)naphthalene. If the change in the concentration of metals in solution for impregnation does not matter, you can use the metal hydroxides.

If the solution to prodlit using a pH meter, realizing that the resulting measurement is not pH within the true water determination. “Measured pH” as used here, will mean a similar pH non-aqueous system using a standard pH probe. Effective even small changes in the measured pH in the transition from the initial solution used for impregnation of the solution with the addition of the base, and improvement in the catalytic properties continue increasing change “measured pH” adding base. Apparently, adding a large number of reasons not adversely affect the operation of the catalyst; however, it was observed that adding large amounts of hydroxides cause formation of a precipitate in the solution for impregnation, which leads to manufacturing difficulties. In the case when the addition of the base is too small, the activity of hydrogen ions will not be affected. The procedure of reduction of the activity of hydrogen ions is also very effective when used by itself, that is, when the impregnation does not reduce the concentration inisheer particles.

The impregnated carrier, also known as the catalyst precursor can be dried in the presence of Atmos is clucalc in itself steam drying, drying under oxygen atmosphere with a controlled oxygen concentration, drying in reducing atmosphere, drying in air and stepwise drying using an appropriate linear or stepwise the temperature curve. By means of example the invention will be described in more detail for a catalyst suitable for the production of epoxides in the gas phase, also known as the catalyst for the epoxidation.

First of all choose the carrier. In the case of the epoxidation catalyst carrier is typically an inorganic substance, for example, such as the carrier based on alumina, such as alumina.

In the case of media containing the aluminum oxide is preferred as the specific surface of which is defined by the method of B. E. T., ranges from 0.03 to 10 m2/g, preferably from 0.05 to about 5 m2/g, more preferably from 0.1 to 3 m2/g and a water pore volume, specific conventional method of water absorption is 0.1 to 0.75 ml/g volume. Method B. E. T. the determination of the specific surface detail Brunauer, S., Emmett, P. Y. and Teller, E., J. Am. Chem. Soc., 60, 309-16 (1938).

Some types of media containing oxide of aluminum, especially predpochitayutsa fact, which have a specific surface area by B. E. I. from 0.1 to 3 m2/g, preferably from 0.1 to about 2 m2/g and a water volume of pores of from 0.10 to about 0,55 ml/year In the number of producers of these media is part of Norton Chemical Process Products Corporation and United Catalysts, Inc. (UCI).

The concentration of undesirable inisheer particles on the carrier surface, reduce to create a “cleaned" of the media. Or, alternatively, the concentration inisheer particles in substances used for the manufacture of the carrier, can be reduced prior to receiving the media. While processing the raw materials for media prepared media can be reprocessed to further improve.

Ionithermie particles on a carrier of alumina, typically include sodium, potassium, aluminates, soluble silicates, calcium, magnesium, silicates and combinations thereof. It was found that silicates and some other anions are particularly undesirable Ionithermie particles in the catalyst for the epoxidation.

After concentration inisheer particles on the surface decreased, the carrier optionally dried. If you use washing water or an organic solvent, to the exclusion of long wear is of him or impregnation its catalytically active metal.

The media controlled by the rate of solubilization is impregnated with metal ions or compound(s), complex(s) and/or salt(salt) dissolved in a suitable solvent sufficient to cause the desired application to the media. If the applied substance is silver, conventional deposition is from 1 to 40 wt.%, preferably from 1 to 30 wt.% silver based on the weight of the entire catalyst. Then the impregnated carrier is separated from the solution and deposited compound of the metal(minerals) reduced to metallic silver.

You can apply one or more promoters, either before or at the same time, or after application of the metal. Promoters catalysts for epoxidation is usually chosen from sulfur, phosphorus, boron, fluorine, metals from group 1A to group VIII, and rare earth metals and combinations thereof. The promoting material, as a rule, is a compound(I) and/or salt(salt) promoter, dissolved in a suitable solvent. For oxide catalysts for the epoxidation of olefins metals of group IA usually chosen from potassium, rubidium, cesium, lithium, sodium, and combinations thereof, with the preferred are potassium and/or cesium and/or rubidium. Even more preferred avesi and rubidium or cesium, and lithium. The metals of group IIA usually chosen from magnesium, calcium, strontium, barium and combinations thereof, transition metals of group VIII are usually chosen from cobalt, iron, Nickel, ruthenium, rhodium, palladium, and combinations thereof, and rare earth metals are usually chosen from lanthanum, cerium, neodymium, samarium, gadolinium, dysprosium, erbium, ytterbium and mixtures thereof. Non-limiting examples of other promoters include perrenate, sulfate, molybdate, tungstate, chromate, phosphate, borate, sulfate anion, fluoride anion, the oxy-anions groups V on VIB, the oxy-anions of an element selected from groups III no VIIB, salts of alkali(aqueous) metal halide anions and the oxy-anions selected from groups IIIA through VIIA and V by VIIB. The amount of promoter metal of group IA is usually in the range from 10 million hours to 1500 hours per million, expressed as metal, by weight of the total catalyst, and the metal of group VIIb less than 3,600 hours per million, expressed as metal, by weight of the total catalyst.

To further improve the catalytic properties of the activity of hydrogen ions solution for impregnation does not necessarily reduce, for example, by adding a base. The usual solution for impregnation in the beginning is pretty basic, so to further reduce the activity of bodoro such as the hydroxide of tetraethylammonium, the lithium hydroxide and cesium hydroxide. To maintain the desired composition of the solution used for impregnation and download metal prefer organic basis. Adding Foundation in these systems usually leads to change “measured pH”, which varies in the range of about 2, with the understanding that “measured pH” is not true pH, because the system for non-aqueous impregnation.

When an excess of the solution for impregnation the impregnated carrier is subsequently separated from the solution prior to recovery of the deposited metal link. In addition, either before or at the same time or after the application of the catalytically active metal on the carrier can also be applied promoters, components, effectively promoting the improvement of one or more catalytic properties of the catalyst compared to a catalyst not containing such components.

You just described the final epoxidation catalysts used to produce epoxides in the gas phase, for example, to obtain ethylene oxide from ethylene and oxygen-containing gas. In this way epoxidation to improve the characteristics of the conversion catalyst to the raw material, you can add one or bol is obtained just as described.

In General terms, the invention is described, and further can be understood referring to the following examples.

EXAMPLES

Media

In table I are given the media used for examples.

aMethod of Brunauer, Emmett and teller, quoted in place.

bThe resistance to crushing of a flat plate, one granule.

cDetermined by the introduction of mercury to 3,8108PA using a Micromeritics Autopore 9210 9200 or (contact angle of 130°, the surface tension of mercury 0,473 N/m).

Methods of washing media water for sample 1, 2, 3, 4, 5, 7, 8, 10, 11, 13

The wash media was carried out by immersing 100 grams of the medium in 300 grams of boiling deionized water for 15 minutes. Then the media was removed and placed in 300 grams of fresh boiling water for 15 minutes. This procedure was repeated once more (a total of three dives); at this point the medium was separated from water and dried in a ventilated oven at 150°C for 18 hours. After that, the dried carrier used for the preparation of the catalyst by the way, the main provisions of which are described in the following examples.

The solution for impregnation

Resource sodium hydroxide dissolved in 2340 ml of deionized water and brought the temperature up to 50°C;

1699 g of silver nitrate high purity “Spectropure” was dissolved in 2100 ml of deionized water and brought the temperature up to 50°C.

To the silver nitrate solution slowly with stirring was added a solution of sodium hydroxide, maintaining the temperature of the solution at 50°C. the Mixture was stirred 15 minutes, then the temperature was lowered to 40°C.

From the precipitate, formed during mixing, removed the water and measured the conductivity of water containing sodium ions and nitrate ions. To a solution of silver newly added volume of fresh deionized water equal to the withdrawn volume. The solution was stirred for 15 minutes at 40°C. This procedure was repeated up until the conductivity of the withdrawn water was not less than 90 kmgdom/see then added to 1500 ml of fresh deionized water.

Added 630 g of dihydrate of oxalic acid of high purity by increments of approximately 100, the Temperature was maintained at 40°C and the pH was maintained above 7.8.

From this mixture were removed water, leaving containing silver suspension of high concentration. Cooled slurry of silver oxalate to 30°C.

Added 699 g (92 wt.%) Ethylenediamine (8% deionized water), keeping the temperature no higher than 30°C. the resulting solution contained n the CsOH and water, after receiving the final catalyst containing a 14.5 wt.% silver and the desired loading of cesium (see examples).

Method for determination of sodium and silicate

RFU analyses were performed on x-ray photoelectron spectrometer VG ESCALAB mkII. As excitation source used nekonkretizovan Al k (1484,6 eV) x-rays. The analyzer electronic kinetic energy was a 150-degree analyzer with a spherical sector, equipped with three-channel electronic omnitele the detecting system. All spectra were obtained with a continuous energy mileage analyzer by setting the energy of the mileage at 50 eV. Before analysis the samples was slightly razmelchite in a mortar and installed in the form of a column of the sample using double-sided tape. The scope of analysis was approximately 3 mm x 5 mm For the correction of the charge used peak A12s and explained it to 118,5 eV. Linear baselines used for measuring the height of the peaks A12s, Si2s and Nals, and the horizontal reference line, starting from the binding energy of 105.5 eV, was used to measure the height of the Si2p line due to interference with augereau line of aluminum. The intensity of peaks was transferred to the relative molar 0,32, Si2s 0,24 and Nals 1,72

and the following dependency:

The measurement results of the RFU are presented in table II. Figures for the RFU measurements represent the number of atoms defined relative to 100 atoms of aluminum. Given the RFU values for silicon are the average values for Si2p and Si2s.

Methods of measuring pH

Measure the pH of a solution of silver was performed using a pH meter model Metrohm 744, using combined electrode model 6.0220.100 and platinum resistance thermometer model 6.1110.100 for temperature compensation. The meter was calibrated commercially available buffer solutions before each use. In the normal dimension of the sample in 50 ml of silver solution with an additive intended for use as impregnation of the catalyst was filtered in a glass chemical glass of 100 ml in 2-micron filter attached to a plastic syringe. In the solution, stir on a magnetic stirrer, lowered the pH probe and recorded after 3 minutes of evidence as the equilibrium pH. Before each measurement the probe was rinsed with deionized water and checked the calibration. Special attention was paid to the fact, ctoa in ammonium hydroxide solution, as recommended by the manufacturer.

Example 1

The catalyst precursor obtained from the carrier And subjecting the first media washing. After washing approximately 30 grams of the washed carrier And placed in a vacuum when to 3.33 kPa for 1 minute at ambient temperature. Then introduced approximately 50 grams of a solution for impregnation to immerse him in the media and kept in vacuum at to 3.33 kPa for 3 minutes. Figure cesium was 450 hours on m/g of the final catalyst. Thereafter, the vacuum was removed and removed from the catalyst precursor excess solution impregnation by centrifugation at 500 rpm for two minutes. Then, the catalyst precursor was dried with shaking at 240°C for 4 minutes in a stream of air flowing with a speed of 11.3 m3/PM

Example 1A (comparative)

The carrier was impregnated as described in example 1, however, this media is not subjected to washing. Figure cesium amounted to 400 hours on m/g of the final catalyst.

Example 2

The media was subjected to washing and impregnation as described in example 1. Figure cesium was 450 hours on m/g of the final catalyst.

He Priaralie washing. Figure cesium amounted to 400 hours on m/g of the final catalyst.

Example 3

The media was subjected to washing and impregnation as described in example 1. Figure cesium amounted to 300 hours on m/g of the final catalyst.

Example 3A (comparative)

The media was impregnated as described in example 1, however, this media is not subjected to washing. Figure cesium amounted to 360 hours on m/g of the final catalyst.

Example 4

Carrier D was subjected to washing and impregnation as described in example 1. Figure cesium amounted to 400 hours on m/g of the final catalyst.

Example 4A (comparative)

Carrier D was impregnated as described in example 1, but the media is not subjected to washing. Figure cesium amounted to 400 hours on m/g of the final catalyst.

Example 5

The media And subjected to washing and impregnation as described in example 1. Figure cesium was 450 hours on m/g of the final catalyst. In addition, the raw material solution for impregnation added 35 wt.%-aqueous hydroxide of tetraethylammonium (TAAG) to rate 117,8 micromoles of HE-/ml Ag, to reduce the activity of hydrogen ions to “measured pH” in the and six times in 300 ml of boiling deionized water each time for 15 minutes. After that, the medium was removed and dried in a ventilated oven at 150°C for 18 hours. Then the carrier was impregnated with an indicator cs 400 hours on m/g of the final catalyst. In addition, in the raw material solution for impregnation was added 35% aqueous hydroxide of tetraethylammonium (TAAG) to reach 117,8 micromoles of HE-/ml Hell in order to reduce the activity of hydrogen ions to “measured pH” 13,6.

Example 7

The media And subjected to promising and impregnated as described in example 1. Figure cesium amounted to 720 hours on m/g of the final catalyst. In addition, TAAG dissolved in water and added in the raw material solution to a value of 117,8 micromoles of HE-/ml Ag in order to reduce the activity of hydrogen ions to “measured pH” 13,2, and NH4Re4dissolved in water and added in the raw material solution to provide 1.5 micromoles of Re/g of the final catalyst.

Example 8

The media And subjected to promising and impregnated as described in example 1. Figure cesium was 450 hours on m/g of the final catalyst. In addition, LiOH dissolved in water and added in the raw material solution for impregnation in order to reduce the activity of the hydrogen ion “s 5, however, the media is not subjected to washing. Figure cesium amounted to 400 hours on m/g of the final catalyst.

Example 9

300 g of the carrier And immersed in 900 ml of boiling 0.1 M solution of ammonium acetate for 15 min, then immersed in 300 ml of deionized water at 25°C. for 15 minutes, after which they were immersed three times in 300 ml of boiling deionized water each time for 15 minutes. Then the media was removed and dried in a ventilated oven at 150°C for 18 hours. Thereafter, the carrier was impregnated as described in example 1. Figure cesium was 450 hours on m/g of the final catalyst. In addition, LiOH dissolved in water and added in the raw material solution for impregnation in order to reduce the activity of hydrogen ions to “measured pH” 13,2.

Example 10

The original substance is aluminum oxide for media And washed with deionised water at 25°C and then homogenized using the same ingredients that were used to produce the carrier And prior to the extrusion, drying and firing in a muffle furnace. The resulting carrier was identified as a carrier of E. Media E used for the preparation of the catalyst as described in example 1. Figure cesium amounted to 360 million hours/year end kata is aktivnosti hydrogen ions to "measured pH" 13,2.

Example 11

Media E used to obtain the catalyst in the same manner as described in example 10, however, this medium was subjected to washing before impregnation. Figure cesium amounted to 510 hours on m/g of the final catalyst. In addition, LiOH dissolved in water and added in the raw material solution for impregnation in order to reduce the activity of hydrogen ions to “measured pH” 13,2.

Example 12

100 g of the carrier And immersed in 300 ml of boiling 0.1 M solution of barium acetate at 25°C for 15 min, then immersed in 300 ml of deionized water at 25°C for 15 min, after which they were immersed three times in 300 ml of boiling deionized water each time for 15 minutes. Then the media was removed and dried in a ventilated oven at 150°C for 18 hours. Thereafter, the carrier was impregnated as described in example 1. Figure cesium amounted to 400 hours on m/g of the final catalyst. In addition, LiOH dissolved in water and added in the raw material solution for impregnation in order to reduce the activity of hydrogen ions to “measured pH” 13,2.

Example 13

The media And subjected to washing and impregnation as described in example 1. Figure cesium was 650 hours on m/g of the final catalyst. In addition, LiOH to “measured pH” 13,2, and NH4Re4dissolved in water and added in the raw material solution to provide 1.5 micromoles of Re/g of the final catalyst.

The catalysts of examples 1-13 were used to produce the ethylene oxide from ethylene and oxygen. In the U-shaped stainless steel tube with an inner diameter of 6.35 mm downloaded from 3 to 5 grams of powdered catalyst. This U-shaped tube was immersed in a bath of molten metal (heat medium), and the ends attached to the flowing gas system. A lot of the used catalyst and the velocity of the incoming gas was adjusted so that the time to achieve flow rate of gas in the 6800 ml of gas per ml of catalyst per hour. Input gas pressure was 1450 kPa.

The gas mixture passed through the catalyst bed (single mode) during the full experimental run (including running), consisted of 25% ethylene, to 7.0% oxygen, 5% carbon dioxide, 63% of nitrogen and from about 2.0 to 6.0.h. per million of chloride ethyl.

The initial temperature of the reactor (heat medium) was 180°C. the Temperature was linearly increased at a rate of 10°C per hour from 180 to 225°C, and then adjusted in such a way as to achieve a constant level of ethylene oxide 1.5% vol. in the exit gases is current in General, at least 1-2 days. Due to small differences in the composition of the raw gas, the velocity of the gas stream and calibration of analytical instruments used to determine the compositions of gaseous raw materials and product, a certain selectivity and activity of this catalyst may vary slightly from one experimental run to another.

Determined initial values manual for selectivity at 1.5% of ethylene oxide and are presented in table III.

You can see that significant improvements in the properties of the catalyst are observed when the catalyst was washed before application to the carrier of the catalytic metal. Another big improvement is observed when a substance used to produce media, washed before manufacture of the media.

The activity of hydrogen ions solution for applying for catalysts in examples 5-13 reduced by adding a base. You can see that the decrease of activity of hydrogen ions further improves the catalytic properties. In addition, it is obvious that the phenomenon of the pH effect is not limited to a particular composition of the catalyst, which is best illustrated in examples 7 and 13, where rasia properties of the catalyst carrier reactions epoxidation of olefins, which consists in removing inisheer particles from the surface of one or more materials from which to receive media, and/or with the surface of the media through their processing, wherein the processing is selected from washing, ion exchange, and combinations thereof and which is carried out to reduce by at least 5% relative to the concentration of silicon atoms on the surface of the carrier determined by x-ray photoelectron spectroscopy, carried out on untreated and media.

2. The method according to p. 1, characterized in that the washing is carried out with the use of an aqueous solution and/or solution-based organic solvent selected from water, hydroxide of tetraethylammonium, ammonium acetate, lithium carbonate, barium acetate, strontium acetate, crown ether, methanol, ethanol, dimethylformamide and mixtures thereof.

3. The method according to any of paragraphs.1-3, characterized in that the processing to reduce the concentration is accompanied by a stage of drying.

4. The method of producing the catalyst by deposition of a catalytically effective amount of one or more catalytically active metals on a carrier obtained according to any one of paragraphs.1-3.

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6. The method according to p. 4 or 5, characterized in that the catalytically active metal and an optional promoting material is applied by dipping the specified media in the solution for impregnation, in which the activity of hydrogen ions is reduced.

7. The method according to any of paragraphs.4-6, characterized in that the catalyst is suitable for the epoxidation of alkene in the gas phase.

8. The method according to p. 7, characterized in that the catalyst is suitable for the epoxidation of ethylene to ethylene oxide, and contains silver as the main catalytically active metal on the carrier based on alumina.

9. Method for the catalytic epoxidation of alkene oxygen-containing gas, in which the use of the catalyst obtained according to any one of paragraphs.4-8.

10. The method according to p. 9, wherein the oxygen-containing gas type, at least one of the oxides of nitrogen.

 

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The invention relates to a method of direct oxidation of propylene to propylene oxide in the vapor phase using molecular oxygen and a certain silver-containing catalysts on the media

The invention relates to a carrier of catalysts and, particularly, to a carrier of catalysts on the basis of ceramic components, for example, of aluminum oxide, which can be used as substrates for metal and metal oxide catalysts used in many chemical reactions

The invention relates to a method for producing a catalyst composition comprising bulk catalyst particles containing at least one base metal of group VIII and at least two metals of group VIB, including the integration and interaction of at least one component made of base metal of group VIII with at least two components of metals of group VIB in the presence of proton fluid, and at least one metal component remains at least partly in the solid state throughout the method, where the metals of groups VIII and VIB range from about 50 to about 100 wt.% in terms of oxides, of the total weight of the specified volume of the catalytic particles, and the solubility of the component metals of these groups, which are at least partly in the solid state during the reaction, is less than 0.05 mol/100 ml water at 18aboutWith

The invention relates to the production of hydrocarbons from synthesis gas

The invention relates to the field of petrochemical, refining, or rather to the catalysts used in the refining

The invention relates to catalysts for the selective decomposition of N2About in a mixture of nitrous gases

The invention relates to the industrial catalyst, its acquisition and its use, especially for the production of 1,2-dichloroethane (EDC) oxychloination of ethylene in the reactor with a fluidized bed or in a reactor with a fixed layer

The invention relates to the hydrogenation refining processes, in particular to catalysts and processes hydrofining petroleum fractions, including oil fractions
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