Method of preparing catalyst carrier and its use in production of catalysts

FIELD: process engineering.

SUBSTANCE: invention relates to composition intended for producing catalyst carrier, to method of producing said carrier, to catalyst and method of its production, and to method of ethylene oxidation in its presence. Proposed composition comprises the mix of at least one alpha aluminium oxide with mean particle size of about 5 mcm or larger in amount of about 20 wt % to about 40 wt % of total content of aluminium oxide in this composition; at least, one hydrated precursor of alpha aluminium oxide in amount of about 60 wt % to about 80 wt % total content of aluminium oxide in this composition; binder and foaming agent. Invention covers also method of producing catalyst carrier comprising producing above described composition and heating it to convert into porous melted structure, method of producing catalyst comprising deposition of catalytically efficient amount of silver on said catalyst carrier, and catalyst produced as described above. It covers also the method of oxidising ethylene to ethylene oxide comprising gas-phase oxidation of ethylene by molecular oxygen in tubular reactor with stationary layer in the presence of produced catalyst.

EFFECT: higher strength and optimum porosity, high selectivity in ethylene oxidation to ethylene oxide at preset ethylene conversion.

19 cl, 1 tbl, 12 ex

The prior art INVENTIONS

The technical field to which the invention relates

This invention relates to a carrier of catalysts for use as carriers for metal components and metal-oxide catalysts, which are then used in many chemical reactions. More specifically, the invention relates to a method for producing a catalyst having as a carrier of alpha alumina with a low surface area, which is suitable as a carrier for silver, and the use of such a catalyst in chemical reactions, especially in epoxydecane of ethylene to ethylene oxide.

Description of the prior art

It is well known that aluminum oxide is used as a carrier of catalysts for epoxidation of olefins. It is particularly suitable as a carrier for a catalyst containing silver, which is used in the oxidation of ethylene to ethylene oxide. Materials carriers produced by melting high-purity aluminum oxide with silicon oxide or without him. For this purpose, the material of the medium often contains 90 wt.% or more alpha alumina and up to 6 wt.% silicon oxide. They are usually very porous and have a high or low surface area depending on the use for which they are received.

At the stage of firing temporary binder burn or thermally decompose to carbon dioxide and water and evaporate. In the art it is known that catalysts based on ceramic carriers include inert solid carriers, such as alpha alumina. They are presented in U.S. patent 3664970; 3804781; 442883 and 4874739. U.S. patents that describe the production of native aluminum oxide include U.S. patents 2499675; 2950169 and 3172866. Such systems have potential application in the field of catalysis, particularly where the basis of alumina is alpha alumina. Other patents, such as U.S. patents 3222129; 3223483 and 3226191 describe the active alumina. Methods of making highly porous alumina is described in U.S. patent 3804781; 3856708; 3907512 and 3907982. The native oxide of aluminum, having high thermal stability, are described in U.S. patent 3928236. Other methods of obtaining carriers of catalysts are described in U.S. patents 3987155; 3997476; 4001144; 4022715; 4039481; 4098874 and 4242233. U.S. patent 3664970 describes media containing mainly aluminum oxide and containing silicon oxide, magnesium oxide and titanium oxide. U.S. patent 4410453 describes that the performance of silver in the catalyst is aluminum oxide in the oxidation of ethylene to ethylene oxide is improved by the introduction of oxide or oxide precursor, zinc, lanthanum and magnesium. U.S. patent 4200552 describes the media, which is obtained from the α-aluminum oxide and at least one connection of SiO₂, TiO₂, ZrO₂, CaO, MgO, B₂O₃, MnO₂or Cr₂O₃as a sintering agent. U.S. patent 4455392 describes the composition wear the El aluminum oxide, which contains silicon oxide and magnesium oxide as components of the binder material. U.S. patent 5100859 describes the media that contains silicate alkaline earth metal, which can be added as an original component or be generated in situ by reaction of silicon oxide or forming the silicon oxide compounds with compounds which decompose to the oxide of the alkali earth metal when heated. U.S. patent 5512530 describes how to obtain a catalyst carrier, which is based on the mixing of alpha alumina, the burnable material and titanium oxide. U.S. patent 5380697 describes media containing ceramic binder containing 60 wt.% silicon oxide, 29 wt.% aluminum oxide, 3 wt.% of calcium oxide, 2 wt.% of magnesium oxide, 4 wt.% oxides of alkali metals and less than 1 wt.% each of the iron oxide and titanium oxide. U.S. patent 5733840 and U.S. patent 5929259 describe the modification of the titanium oxide molded carriers. This processing involves the impregnation of a pre-molded carrier with a solution of oxalate of Titania, bis(ammoniacal)dihydroxide titanium (IV) or a similar organic salts, and then the impregnated carrier is calcined at a temperature of from about 450 to 700°C. the Patents describe that if the titanium oxide added during preparation of media, it has the tendency to affect the seal structure of the carrier, which can lead to unacceptable properties. U.S. patent 4368144 establishes that the best catalytic performance was obtained with media containing not more than 0,07% Na. U.S. patent 6103916 describes that the performance of the catalyst was improved when the carrier was washed by boiling in clean water until the water resistance was not more than 10000 Ohm·see U.S. Patent 5384302 describes the media based on α-aluminum oxide, which was prepared by mixing at least two components of aluminum oxide. The first provides 95-40% from all components of aluminum oxide and is made of α-alumina with a crystallite size of 0.4-4 μm.

One of the problems of catalysts based on porous media, is that they are not a homogeneous pore structure. U.S. patent 4022715 trying to solve this problem by the use of organic foaming agents, which are mixed with the composition of the precursor medium. It was found that improved pore structure of the carrier can be formed by using the composition of the catalyst carrier, which contains a mixture of intermediate alumina to alpha alumina, or without having an average particle size of about 5 microns or more; and a binder. This composition is applied and does not contain the seed particles. Optionally, the composition may either be of solid foam, which expands or discharge gas after the application of sufficient heat, talc and/or a water-soluble compound of titanium.

The catalyst carrier of the present invention has excellent tensile fragmentation, porosity and surface area, which will be applied catalytic component. The optimum porosity and surface area are important for the catalytic function and guarantee the absence of diffusion limitations for gaseous reactants and products in the reaction conditions. The minimum surface area is important because it provides a framework that will be applied to the catalytic component. Tensile fragmentation is a parameter of the physical integrity of the media. This physical strength is essential to the ability of the catalyst to withstand handling, as well as his long service in a commercial reactor. The carrier, which has an optimum surface area and porosity, may have insufficient resistance to fragmentation, and Vice versa. It is important the balance between the various physical parameters of the media. Typically the carrier, which has an optimum surface area and porosity, may have insufficient resistance to fragmentation, and Vice versa. Proper selection of the characteristics of alpha alumina, which is used in the media, will help in balance between properties of the resulting media. The optimal ratio between these characteristics is obtained by selecting the component carrier according to this invention.

The INVENTION

In one embodiment, the invention provides a composition for receiving the catalyst carrier, which includes a mixture of at least one alpha alumina having an average particle size of about 5 μm or more in an amount of from about 20 wt.% to about 60 wt.% of the total content of alumina in the composition; at least one hydrated precursor of alpha alumina in an amount of from about 40 wt.% to about 80 wt.% of the total content of alumina in the composition; and a binder; and the composition contains almost no germ particles.

Another variant of the invention provides a method of obtaining a catalyst carrier, which comprises the following stages:

a) preparation of the composition to obtain a catalyst carrier, which comprises a mixture of at least one alpha alumina having an average particle size of about 5 μm or more in an amount of from about 20 wt.% to about 60 wt.% of the total content of alumina in the composition; at least one hydrate the fragmented precursor of alpha alumina in an amount of from about 40 wt.% to about 80 wt.% of the total content of alumina in the composition; and a binder; and the composition contains almost no germ particles; then

b) molding the resulting composition into the structure; then

(C) heating the above-mentioned structure for a sufficient time and at sufficient temperature to produce a porous structure; and then

d) heating this porous structure for a sufficient time and at sufficient temperature to the transformation of the intermediate alumina to alpha alumina, a porous structure of alpha alumina, by fusing this porous structure and thereby the formation of the catalyst carrier.

Another variant of the invention provides a method of obtaining a catalyst carrier, which contains:

a) preparation of the composition to obtain a catalyst carrier, which contains at least one hydrated precursor of alpha alumina and a binder; and the composition contains almost no alpha alumina and contains almost no germ particles; then

b) molding the resulting composition into the structure; then

(C) heating the above-mentioned structure for a sufficient time and at sufficient temperature to produce a porous structure; and then

d) heating this porous structure for a sufficient time and under DOS is enough temperature transformation of hydrated precursor of alpha alumina, alpha alumina, the formation of porous structure of alpha alumina, by fusing this porous structure and thereby the formation of the catalyst carrier.

DETAILED description of the INVENTION

The first variant of implementation of the present invention provides a composition for receiving the catalyst carrier, which includes a mixture of at least one alpha alumina having an average particle size of about 5 μm or more in an amount of from about 20 wt.% to about 60 wt.% of the total content of alumina in the composition; at least one hydrated precursor of alpha alumina in an amount of from about 40 wt.% to about 80 wt.% of the total aluminum content in the composition; and a binder; and the composition contains almost no germ particles. In this embodiment, alpha aluminum oxide is preferably present in amount from about 40 wt.% to about 60 wt.% of the total content of aluminum oxide in the composition. In this embodiment, at least one hydrated precursor of alpha alumina is present in an amount of from about 40 wt.% to about 60 wt.% of the total content of aluminum oxide in the composition. In the context of this invention germ particles are particles that create nucleation centers for the image is of alpha alumina from hydrated predecessor.

In another embodiment is provided a composition for receiving the catalyst carrier, which contains at least one hydrated precursor of alpha alumina and a binder; and the composition contains almost no alpha alumina and contains almost no germ particles.

The hydrated precursor of alpha alumina may contain aluminum hydroxide such as gibbsite, boehmite, diaspore, bayerite, and combinations thereof. The full amount of aluminum oxide, which is an alpha alumina plus hydrated precursor of alpha alumina, an intermediate aluminum oxide), may be present in the composition in an amount of from about 80 wt.% to about 100 wt.% in the calculation of the mass of the target media. It preferably is present in an amount of from about 90 wt.% to about 99 wt.% in the calculation of the mass end of the carrier, more preferably from about 97 wt.% to about 99 wt.% in the calculation of the mass of the target media. Preferably the composition contains almost no iron oxide, chromium oxide and particles of alpha alumina submicron size.

This composition is prepared by education physical mixture of the components of the composition. A binder can be a temporary binder, a permanent binder, or both. Temporary binder pre whom are thermally degradable organic compounds of medium to high molecular weight. Permanent binders are inorganic clay materials, which give mechanical strength to the final medium.

Temporary binder and burning materials include thermally-degradable organic compounds, poliolefinas, oil, for example oil, gum Arabic, carbon materials such as coke, carbon powders, graphite, cellulose, substituted cellulose, such as methylcellulose, ethylcellulose and carboximetilzellulozu, ethers, cellulose, stearates, such as esters of stearates, for example methyl - or telstart, waxes, powdered plastics, such as polyolefins, in particular polyethylene and polypropylene, polystyrene, polycarbonate, sawdust, starch, and powdered walnut shell powder, for example-shell pecans, cashews, walnuts and hazelnuts, and combinations thereof, and the like, which burn when applied firing temperature. Burning materials are mainly used to ensure the preservation of the structure during the pre-or unfired phase, in which the mixture can be formed into particles by means of molding or extrusion, as well as to provide the desired porosity of the final product. In the case of application, a temporary binder essentially completely removed during firing by the end of the media. Media the data of the invention preferably are made with the introduction of the permanent binder material, to ensure the preservation of the porous structure and to provide additional strength to the media after burning media. Persistent carriers include inorganic clay materials, silicon oxide, oxides of alkaline earth metals, oxides of alkali metals and titanium oxide, silicates of elements of group II of the periodic system of elements and their combinations. Suitable clay does not necessarily include kaolinite. Handy binder material, which may be embedded in particles of aluminum oxide, is a mixture of boehmite, stabilized silicates and soluble salts of sodium. Suitable binder materials for the present invention include calcium silicate and magnesium silicate to be added or formed in situ. Preferably, however, not to use the free alkali metals or their oxides. A binder may be present in the precursor in an amount of from about 0.1 wt.% to about 15 wt.% based on the weight of the composition, preferably from about 0.2 wt.% up to about 10 wt.% based on the weight of the composition and more preferably from about 0.5 wt.% up to about 5 wt.% based on the weight of the composition.

The composition may optionally contain a solid foam, which expands or allocates gas under the application of sufficient heat. In one embodiment, the foaming agent contains the composition of the microspheres, which include thermoplastic membranes that encapsulate hydrocarbons. This hydrocarbon expands the data thermoplastic shell with the application of sufficient heat. Such foaming agents include gas-tight thermoplastic shell that can encapsulate the hydrocarbon in liquid form. When heated hydrocarbon turns into gas and increases its pressure, while thermoplastic shell softens, resulting in an increase in the volume of the microspheres. Examples of the expanding microspheres are Advancell, areas on the basis of Acrylonitrile, commercially available from Sekisui Chemical Co. (Osaka, Japan), and microspheres Expancel^®, commercially available from Expancel, Stockviksvrken, Sweden. Expancel is available in the form of unexpanded and expanded microspheres. Unexpanded microspheres have a diameter from about 6 to about 40 microns, depending on the variety. When heated, these microspheres expand to from about 20 to about 150 microns in diameter. The preferred hydrocarbon inside the shell is isobutane or isopentane. The shell preferably is a copolymer of monomers, such as vinylidenechloride, Acrylonitrile, and methyl methacrylate. In another embodiment, the foaming agent may be a solid granular chemical foaming agent which decomposes when heated, from the Yaya significant amount of gaseous products of decomposition, leading to the formation of pores. Chemical blowing agents preferably are solid forms of hydrazine derivatives, which emit gases such as CO₂and nitrogen. Examples of chemical foaming agents are p-toluensulfonate, benzosulfimide and azodicarbonamide, H₂NCO-N=N-CONH₂. Azodicarbonamide decomposes at 200°C in N₂, Co and CO₂.

Appropriate amount of foaming agent to provide the desired porosity may be in the range from about 0.1 wt.% to about 30 wt.% based on the weight of the entire composition. Preferably the amount of the foaming agent varies from about 1 wt.% to about 20 wt.% and more preferably from about 3 wt.% to about 15 wt.% based on the weight of the composition. The amount of foaming agent is a function of its type, the type used components of alpha alumina and/or intermediate alumina, and the nature of the porosity, which is desired in the final product.

After thorough dry mixing of alpha alumina, hydrated precursor of alpha alumina, a binder and, optionally, a foaming agent, a sufficient amount of water is added to the weight of its predecessor, getting paste-like substance. Water and/or water-containing substance is added to the source precursor, to give a mixture of plastic is th. The plastic mixture is then formed into the desired shape using standard processing methods ceramics, such as tableting or extrusion. The amount of water added to the precursor medium will be a function of the method used to obtain a paste. Extrusion may require adding a high level of water to achieve the optimal level of plasticity. When the particles are formed by extrusion, it is possible to introduce regular helpers extrusion, such as lubricants, such as vaseline or petroleum products. The lubricant can be present in the precursor in an amount of from about 0.1 wt.% up to about 10 wt.% based on the weight of the composition, preferably from about 0.5 wt.% up to about 5 wt.% based on the weight of the composition and more preferably from about 1 wt.% up to about 3 wt.% based on the weight of the composition. The number of used components to some extent independent and will depend on a number of factors that relate to the equipment used. However, it is well known to experts in the field of extrusion of ceramic materials. Preparation of a catalyst carrier typically includes a step of mixing material precursor into a desired shape and desired size. The particles of the catalyst carrier is then formed from the paste using conventional means, such as, for example, tableting, extras is I high pressure, granulation or other processing methods ceramics. For use in commercial receipt of ethylene oxide carriers, it is desirable to mould as a regular form of pellets, spheres, rings, particles of wood, pieces, wagon wheels, cylinders, trichloracetic, chetyrehlistnik and with such a size suitable for use in reactors with a fixed layer. Preferably, the carrier particles had an equivalent diameter in the range from about 3 mm to about 20 mm and preferably in the range of from about 4 mm to about 12 mm, which are generally compatible with the inner diameter of the tubular reactor, in which place the catalyst. "Equivalent diameter" is the diameter of a sphere having the same external surface (i.e. neglecting surface within the pores of the particles) to the extent used as carrier particles. These particles are then dried and then calcined at an elevated temperature. The function of the stage of drying is to remove water from the molded tablets. Molded precursor of the carrier is dried at a temperature of from about 80°to about 150°C for a time sufficient to remove essentially all water. Then extruded material is calcined under conditions sufficient to remove combustible agents and organic binder and fusing the particles of alpha alumina in the porous solid is th mass. The carrier is heated at a temperature which is sufficiently high to sinter the particles of aluminum oxide and to obtain a structure with physical properties that withstand the environment in which, as expected, they will work. The temperature and duration of calcination should be high enough to turn any intermediate alumina to alpha alumina and inducing fusion of grain boundaries. The regulation method of annealing is essential for obtaining a carrier having an optimal ratio between the surface area, porosity and strength. Typically, the temperature of annealing is higher than 1000°C., preferably lies in the range from 1150°C. to about 1600°C. the Time of incubation under these maximum temperatures for education media typically comprise from about 0 hours to 10 hours, preferably from about 0.1 hours to about 10 hours, preferably from about 0.2 hours to about 5 hours.

The final medium is water pore volume ranging from about 0.2 cm³/g to about 0.8 cm³/g, preferably from about 0.25 cm³/g to about 0.6 cm³/g surface Area by the BET target media preferably lies in the range 0.4-4.0 m²/g, more preferably from about 0.6 to about 1.5 m²/, a Suitable value of tensile splitting is about 8 pounds of the above preferably about 10 pounds or higher, and more preferably about 14 pounds and above. Suitable porosity is expected in the range of from about 20 to about 80%, preferably from about 25 to about 50%.

In another embodiment of this invention, the catalyst carrier prepared as described above except that the composition contains talc instead of or in addition to the permanent binder component. Talc may be present in the precursor in an amount of from about 0.1 wt.% to about 15 wt.% based on the weight of the composition, preferably from about 0.5 wt.% up to about 10 wt.% based on the weight of the composition and more preferably from about 1 wt.% to about 8 wt.% based on the weight of the composition. The media is then formed in the same way as described above.

In another embodiment of this invention, the catalyst carrier prepared as described above except that the composition contains a water-soluble compound of titanium instead of or in addition to the permanent binder. Suitable water-soluble titanium non-exceptionally include hexaferrite ammonium oxalate of Titania and bis(ammoniacal)dihydroxide titanium (IV). Water-soluble compound of titanium may be present in the precursor in an amount of from about 0.01 wt.% up to about 10 wt.% in the calculation of the mass is oppozitsii, preferably from about 0.1 wt.% to about 8 wt.% based on the weight of the composition and more preferably from about 0.2 wt.% up to about 5 wt.% based on the weight of the composition. The media is then formed in the same way as described above. The optional addition of a small amount of boron added in the form of boric acid or borate, also gives good results. The amount of added boron is in the range from 0.0 to 3% (based on dry weight of the used alumina.

To obtain a catalyst for oxidation of ethylene to ethylene oxide, formed above the carrier then provide a catalytically effective amount of silver. The catalysts are prepared by impregnation of carriers ions, compounds, complexes and/or salts of silver, dissolved in a solvent suitable to cause the deposition of compounds predecessor of silver on the carrier. The impregnated carrier is then removed from the solution and the precipitated compound of silver is reduced to metallic silver by high-temperature annealing. Also preferably precipitated on a carrier before, together or after the deposition of silver suitable promoters in the form of ions, compounds and/or salts of alkali metals dissolved in a suitable solvent. Also precipitated on a carrier before, together or after the deposition of silver and/or alkali metal is and suitable connections, complexes and/or salts of the transition metal dissolved in an appropriate solvent.

Carriers formed above, is impregnated with the impregnating solution of silver, preferably an aqueous solution of silver. The media also impregnated at the same time or at a particular stage of various catalytic promoters. Preferred catalysts prepared according to this invention contain up to about 45 wt.% silver calculated on a metal deposited on the surface and in the pores of the porous structure. The content of silver calculated on a metal from about 1 to about 40% based on the weight of the entire catalyst is preferred, although the silver content of from about 8 to about 35 wt.% is more preferable. The amount of silver deposited on the carrier or present on the media, represents such an amount which is catalytically effective amount of silver, i.e. the amount that is economically accelerates the reaction of ethylene and oxygen with the receipt of ethylene oxide. Used herein, the term "catalytically effective amount of silver" refers to the amount of silver, which provides a measurable conversion of ethylene and oxygen to ethylene oxide and stability, selectivity and activity over the lifetime of the catalyst. Suitable containing silver sedimentological include the oxalate of silver, silver nitrate, silver oxide, silver carbonate, silver carboxylate, silver citrate, phthalate, silver, silver lactate, propionate, silver butyrate and silver salts of higher fatty acids, and combinations thereof.

This catalyst contains a catalytically effective amount of silver, a promoting amount of alkali metal, a promoting amount of a transition metal deposited on a porous carrier. Used herein, the term "promoting amount" of a certain component of the catalyst means such quantity of this component, which works efficiently, ensuring the improvement of one or more of the catalytic properties of this catalyst compared to a catalyst not containing the mentioned components. The exact applied concentration, of course, will depend, among other factors, the desired silver content, the nature of the medium, the viscosity of the liquid and the solubility of silver compounds.

In addition to the silver catalyst also contains the promoter of an alkali metal selected from lithium, sodium, potassium, rubidium, cesium or combinations thereof, and cesium is preferred. The amount of alkali metal deposited on a carrier or catalyst or present on the carrier or the catalyst should be promoting. Preferably this kolichestvom in the range from about 10 ppm to about 3000 ppm, more preferably from about 50 ppm to about 2000 ppm and even more preferably from about 100 ppm to about 1500 ppm and even more preferably from about 200 ppm to about 1000 ppm based on the weight of total catalyst, measured as the metal.

The catalyst also preferably contains a promoter of the transition metal, which contains an element from groups 4b, 5b, 6b, 7b and 8 of the periodic system of elements and their combinations. Preferably the transition metal contains an element selected from the group 6b and 7b of the periodic system of elements. Preferred transition metals are rhenium, molybdenum and tungsten, and molybdenum and tungsten are the most preferred. The amount of the promoter of the transition metal deposited on the carrier or the catalyst or present on the carrier or the catalyst should be promoting. The promoter of the transition metal may be present in an amount of from about 0.1 micromol per gram to about 10 micromol per gram, preferably from about 0.2 micromol per gram to about 5 micromol per gram and more preferably from about 0.5 micromol per gram to about 4 micromol per gram of total catalyst, calculated on the metal.

The silver solution used for impregnation of the carrier may also contain an optional solvent or who is lesoobrazuyushchei/dissolving agent, such as agents known in the art. A wide variety of solvents or complexing/solvent agents may be used to dissolve the silver in the desired concentration in the impregnating medium. Suitable complex-forming/dissolving agents include amines, ammonia or lactic acid. Amines include alkylenediamine and alkanolamine having from 1 to 5 carbon atoms. In one preferred embodiment, the solution contains an aqueous solution of silver oxalate and Ethylenediamine. Complex-forming/dissolving agent may be present in the impregnating solution in an amount of from about 0.1 to about 5.0 moles of Ethylenediamine per mole of silver, preferably from about 0.2 to about 4.0 and preferably from about 0.3 to about 3.0 moles of Ethylenediamine per mole of silver.

When using the solvent, it can be aqueous or organic, and may be polar or substantially or completely non-polar. In General, the solvent should be sufficient solutious power to dissolve the components of the solution. At the same time, preferably, when the solvent is chosen so as to avoid undue influence on dissolved promoters or interact with them. The concentration of silver salts in the solution ranges from about 1 wt.% to mA the maximum permissible solubility specific applicable combination of salt/ solvent agent. Usually it is very convenient to use solutions of silver salts containing from 5 to about 45 wt.% silver, and the concentration of silver salts from 10 to 35 wt.% are preferred.

Impregnation of the selected media perform in the usual manner by impregnation with an excess of solution, resulting humidity, etc. is Usually the material of the carrier is placed in the silver solution until a sufficient amount of solution is absorbed by the media. Preferably the amount of silver solution used for impregnation of porous media, not more than necessary to fill the pore volume of the carrier. Containing silver liquid penetrates into the pores of the carrier by means of absorption, capillary action and/or vacuum. Can be used for one treatment or a series of impregnations with intermediate drying or without depending, in part, on the concentration of silver salts in the solution. Procedures for impregnation are described in U.S. patents 4761394, 4766105, 4908343, 55057481, 5187140, 5102848, 5011807, 5099041 and 5407888, which are incorporated here by reference. Can be used with previously known procedures preliminary precipitation, coprecipitation and postcardmania different promoters.

Examples of catalytic properties include, among other things, control (stability in out-of-control), selectivity, activity, conversion, stability and output. Specialist in e is authorized technology clear that one or more separate catalytic properties may increase "promoting amount", while other catalytic properties can be enhanced or not, or may even deteriorate. It is also clear that different catalytic properties can be enhanced in different operating conditions. For example, a catalyst having improved selectivity under one set of operating conditions, can operate with a different set of conditions, when the improvement is rather manifested in activity than in selectivity, and the operator of the ethylene oxide is intentionally change working conditions in order to benefit from certain catalytic properties even when the catalytic reduction of other properties to optimize conditions and results, taking into account the cost of raw materials, energy costs, cost of removal of by-products and the like. The specific combination of silver, media, promoter of alkaline metal and promoter of the transition metal of the present invention is to provide improvement in one or more catalytic properties compared with the same combination of silver and the media, but without promoter or with only one promoter.

After impregnation of the carrier impregnated with connection predecessor of silver and promoters, calcined or activated in the course of time, dost is accurate, to restore the silver component to metallic silver and to remove the solvent and volatile decomposition products from containing silver media. The calcination is carried out by heating the impregnated carrier, preferably gradually, to a temperature in the range from about 200°to about 600°C., preferably from about 230°to about 500°C. and more preferably from about 250°to about 450°C. when the reaction pressure in the range from 0.5 to 35 bar for a time sufficient to convert the contained silver to metallic silver and to decompose all or substantially all organic materials and remove them in the form of volatile substances. In General, the higher the temperature, the shorter the required period of calcination. A wide range of periods of heat available in the art for heat treatment of the impregnated carrier, for example, U.S. patent No. 3563914 offers heat in less than 300 seconds, U.S. patent No. 3702259 describes heating from 2 to 8 hours at a temperature of from 100°C to 375°C for recovery of silver salts in the catalyst; usually within from about 0.5 to 8 hours, however, it is important that the recovery time is correlated with the temperature so that was essentially complete recovery of silver salts to the catalytically active metal. Continuous or step program heat is and can be used for this purpose.

Impregnated carrier remain in the atmosphere containing an inert gas and, possibly, oxygen-containing oxidizing component. In one embodiment, the oxidizing component is present in amount from about 10 ppm to about 5% of the volume of gas. For the purposes of this invention, inert gases are defined as gases which essentially do not react with creating the catalyst components in the selected conditions for preparation of the catalyst. These gases include nitrogen, argon, krypton, helium, and combinations thereof, and the preferred inert gas is nitrogen. In a suitable embodiment, the atmosphere contains oxygen-containing oxidizing component is from about 10 ppm to about 1% of the volume of gas. In another suitable embodiment, the atmosphere contains oxygen-containing oxidizing component is from about 50 ppm to about 500 ppm of gas.

Receipt of ethylene oxide

Usually commercially implemented methods of obtaining of ethylene oxide is carried out by continuous interaction of oxygen-containing gas with ethylene in the presence of this catalyst at a temperature in the range from about 180°to about 330°C. and preferably from about 200°to about 325°C., more preferably from about 210°to about 270°C at a pressure which may vary from about atmospheric pressure up according to the Board about30 atmospheres, depending on the desired mass flow rate and performance. Higher pressures, however, can be applied within the scope of this invention. Stay in large-scale reactors is usually on the order of about 0.1-5 seconds. Oxygen can be supplied to the reaction in the oxygen-containing stream such as air or commercial oxygen. The resulting ethylene oxide is separated and recovered from the reaction products using conventional methods. However, in this invention the method of producing ethylene oxide involves the usual gas return covering the return of carbon dioxide in the usual concentrations, for example about 0.1 to 15 volume percent. The usual method of oxidation of ethylene to ethylene oxide contains gas-phase oxidation of ethylene with molecular oxygen in the presence of the catalyst according to the present invention in a tubular reactor with a fixed bed. Normal commercial reactors for the production of ethylene oxide with a fixed layer have usually the form of multiple parallel elongated tubes (in a suitable enclosure) from about 0.7 to 2.7 inches outside diameter (VD) and from 0.5 to 2.5 inches internal diameter (GNI) and from 15 to 45 feet in length, filled with a catalyst.

It was shown that the catalysts according to the present invention are particularly selective catalytic oxidation of ethylene with molecular oxygen to ethylene oxide. Conditions PROTEK is of this oxidation reaction in the presence of catalysts of the present invention in General contain conditions, described in the prior art. This applies, for example, to suitable temperatures, pressures, residence time, dilution materials such as nitrogen, carbon dioxide, steam, argon, methane, the presence or absence of retarding agents to control the catalytic action, such as ethylchloride, 1,2-dichloroethane or vinyl chloride, if necessary, use operations return or successive transformations in different reactors to increase yield of ethylene oxide, and any other specific conditions that can be selected in the methods of production of ethylene oxide. Molecular oxygen is used as the reagent, can be obtained from conventional sources. A suitable supply of oxygen may represent a relatively pure oxygen, concentrated oxygen stream containing oxygen in a large amount with smaller amounts of one or more diluents, such as nitrogen, argon, etc. or another oxygen-containing stream such as air. The use of the catalyst of the present invention in the oxidation reaction of ethylene in no way restricted to the specific conditions of the terms and conditions, which are known as effective.

The resulting ethylene oxide is separated and recovered from the reaction products using the normal with osobov, known and used in the art. The use of the silver catalysts of the present invention in methods of production of ethylene oxide gives a higher full selectivity of the oxidation of ethylene to ethylene oxide at a given conversion of ethylene than is possible with conventional catalysts.

Upon receipt of ethylene oxide mixture supplied reagents may contain from 0.5 to 45% ethylene and from 3 to 15% oxygen with the balance containing relatively inert materials, including substances such as nitrogen, carbon dioxide, methane, ethane, argon and the like. In the preferred application of the silver catalysts of this invention, the ethylene oxide when oxygen-containing gas contains about 95% oxygen or more. Only a portion of the ethylene is usually reacts when passing over the catalyst, and, after separation of the desired product of ethylene oxide and remove the purge stream and carbon dioxide to prevent the unregulated growth of inert compounds and/or by-products, unreacted materials are returned to the oxidation reactor. Only for purposes of illustration, the subsequent is a condition that is often used in modern nodes of commercial reactors for the production of ethylene oxide. GHSV - 1500-10000; input pressure of 150-400 psig; supplied raw materials: ethylene 1-40%; O_{2 - 3-12%; CO2the 0.1 - 40%; ethane 9-3%; argon, and/or methane and/or nitrogen: 0.3 to 20 ppm (vol.) just diluting chlorophenothane moderator; cooler temperature - 180-315°C; the temperature of the catalyst - 180°C; conversion Of2- 10-60%; receiving EA (working speed) - 2-16 lbs EA/cu.ft catalyst/h}

Further non-limiting examples serve to illustrate the present invention.

EXAMPLE 1

The following components were thoroughly stirred:

100 grams of alpha aluminum oxide (I)^*

120 grams of alpha aluminum oxide (II)^**

290 g of hydrated alumina (gibbsite)

60 g of boehmite

14 g CM Methocel (methyl cellulose)

2 g of gum Arabic

94 g of polycarbonate powder

25 g of mineral oil

8 g of 50% Ti solution (in the form of bis-amarillasinternet titanium)

30 g of talc

143 g of water

* Alpha aluminum oxide (I) is a high-purity alpha alumina which has a surface area according to BET 0.7 m²/g and the content of Na less than 0.3%.

** Alpha alumina (II) is a high-purity alpha alumina which has a surface area according to BET of 11 m²/g and the content of Na is less than 0.15%.

Stage 1

All dry ingredients were mixed together in the mixer of dry powders (US Stoneware Model M93120DC). The dry mixture was transferred into a mixer intense shear (Lancaster Model 530PO). It see is stirred with water and water-soluble components and the mixing continued for more than 15 minutes.

Stage 2

This plastic mixture was extrudible 8-mm hollow cylinders using a Killion extruder (model 4321111282).

Stage 3

The molded pellets were dried at 120°C and then annealed by slow and programmable scheme. The firing method includes heating the raw product in a high temperature furnace using furnace CM (model 1720). The firing circuit includes temperature rise at a speed of 4°C/min up to 1275°C. the oven Temperature was maintained at this level for 2 hours and then it was allowed to cool down with a speed of 6°C/min, the media referred to as carrier A. Testing media showed that he has the following options:

EXAMPLE 2

The following components were thoroughly stirred:

176 grams of alpha aluminum oxide (II)^**

232 g of hydrated alumina (gibbsite)

48 g of boehmite

15 g CM Methocel (methyl cellulose)

2 g of gum Arabic

80 g of azodicarbonamide

20 g of mineral oil

6.2 g of 50% Ti solution (in the form of bis-ammoniate is dihydroxide titanium)

16 g of talc

105 g of water

Mixing, molding and drying of these components was performed, following the same procedure as in example 1. The firing circuit includes temperature rise at a speed of 4°C/min to 1350°C. the oven Temperature was maintained at this level for 2 hours before it was allowed to cool at 5°C/min, the media referred to as Century media Test media showed that he has the following options:

EXAMPLE 3

The following components were thoroughly stirred:

240 grams of alpha aluminum oxide (I)^*

200 grams of alpha aluminum oxide (II)^**

580 g of hydrated alumina (gibbsite)

120 g of boehmite

28 g A4 Methocel (methyl cellulose)

94 g of polycarbonate powder

50 g of mineral oil

15.6 g of 50% Ti solution (in the form of bis-amarillasinternet titanium)

40 g of talc

216 g of water

Mixing, molding and drying of these components was performed, following the same procedure as in example 1. Diagram of the firing includeda temperature rise at a speed of 4°C/min to 1350°C. The oven temperature was maintained at this level for 2 hours before it was allowed to cool at 5°C/min, the media referred to as the carrier C. Testing media showed that he has the following options:

EXAMPLE 4

The following components were thoroughly stirred:

176 grams of alpha aluminum oxide (II)^**

232 g of hydrated alumina (gibbsite)

48 g of boehmite

12 g CM Methocel (methyl cellulose)

30 g of the powder, walnut shell

20 g of mineral oil

6.2 g of 50% Ti solution (in the form of bis-amarillasinternet titanium)

16 g of talc

108 g of water

Mixing, molding and drying of these components was performed, following the same procedure as in example 1. The firing circuit includes temperature rise at a speed of 4°C/min to 1350°C. the oven Temperature was maintained at this level for 2 hours before it was allowed to cool at 5°C/min, Test media showed that he has the following parameters : the s:

EXAMPLE 5

The following components were thoroughly stirred:

220 grams of alpha aluminum oxide (II)^**

282 g of boehmite

15 g CM Methocel (methyl cellulose)

50 g of the polycarbonate powder

25 g of mineral oil

7,8 g 50% Ti solution (in the form of bis-amarillasinternet titanium)

20 g of talc

108 g of water

Mixing, molding and drying of these components was performed, following the same procedure as in example 1. The firing circuit includes temperature rise at a speed of 4°C/min to 1350°C. the oven Temperature was maintained at this level for 2 hours before it was allowed to cool at 5°C/min, the media referred to as the carrier D. the Testing media showed that he has the following options:

EXAMPLE 6

The following components were thoroughly stirred:

220 grams of alpha aluminum oxide (II)^**

290 g of hydrated alumina (gibbsite)

60 g of boehmite

15 g CM Methocel (methyl cellulose)

50 g of the polycarbonate powder

25 g of mineral oil

20 g of talc

115 g of water

Mixing, molding and drying of these components was performed, following the same procedure as in example 1. The firing circuit includes temperature rise at a speed of 4°C/min to 1350°C. the oven Temperature was maintained at this level for 2 hours before it was allowed to cool at 5°C/min, the media referred to as the carrier that is Testing the media showed that he has the following options:

EXAMPLE 7

The following components were thoroughly stirred:

510 g of hydrated alumina (gibbsite)

195 g of boehmite

15 g CM Methocel (methyl cellulose)

75 g of the powder is olycarbonate

25 g of mineral oil

8 g of 50% Ti solution (in the form of bis-amarillasinternet titanium)

20 g of talc

10 g of ammonium fluoride

195 g of water

Mixing, molding and drying of these components was performed, following the same procedure as in example 1. The firing circuit includes temperature rise at a speed of 4°C/min to 1250°C. the oven Temperature was maintained at this level for 2 hours before it was allowed to cool at 5°C/min, the media referred to as the carrier F. Testing media showed that he has the following options:

EXAMPLE 8

The following components were thoroughly stirred:

389 g of hydrated alumina (gibbsite)

111 g of boehmite

18 g CM Methocel (methyl cellulose)

5 g of Expancel 551

to 25.0 g of mineral oil

7,8 g 50% Ti solution (in the form of bis-amarillasinternet titanium)

20 g of talc

108 g of water

Mixing, molding and drying of these components was performed, following the same procedure as in example 1. With the EMA firing included temperature rise at a speed of 4°C/min up to 1375°C. The oven temperature was maintained at this level for 2 hours before it was allowed to cool at 5°C/min, the media is indicated as the carrier of G. Testing media showed that he has the following options:

EXAMPLE 9

The following components were thoroughly stirred:

60 grams of alpha aluminum oxide (I)^*

60 grams of alpha aluminum oxide (II)^**

280 g of hydrated alumina (gibbsite)

80 g of boehmite

28 g CM Methocel (methyl cellulose)

5 g of Expancel 551

25 g of mineral oil

7,8 g 50% Ti solution (in the form of bis-amarillasinternet titanium)

20 g of talc

108 g of water

Mixing, molding and drying of these components was performed, following the same procedure as in example 1. The firing circuit includes temperature rise at a speed of 4°C/min up to 1325°C. the oven Temperature was maintained at this level for 2 hours before it was allowed to cool at 5°C/min, the media referred to as the carrier H. In the Finance media showed he has the following options:

EXAMPLE 10

The following components were thoroughly stirred:

170 grams of alpha aluminum oxide (II)^**

333 g of hydrated alumina (gibbsite)

167 g of boehmite

15 g CM Methocel (methyl cellulose)

75 g of the polycarbonate powder

25,0 mineral oil

8 g of 50% Ti solution (in the form of bis-amarillasinternet titanium)

20 g of clay (water aluminum silicate)

120 g of water

Mixing, molding and drying of these components was performed, following the same procedure as in example 1. The firing circuit includes temperature rise at a speed of 4°C/min up to 1375°C. the oven Temperature was maintained at this level for 2 hours before it was allowed to cool at 5°C/min, Test media showed that he has the following options:

EXAMPLE 11

A. Preparation of the starting solution of the complex silver/amine

The silver solution was prepared using the following components (the parts are given by weight):

The silver oxide was mixed with water at room temperature, followed by gradual addition of oxalic acid. The mixture was stirred for 15 minutes, and at this point the color black suspension of silver oxide was changed to a light brown color of silver oxalate. The mixture was filtered and the solid residue washed with 3 liters of distilled water.

This sample was placed in a bath of ice and stirred until the Ethylenediamine and water (in the form of a mixture of 66%/34%) was slowly added, maintaining the reaction temperature below 33°C. After adding all of the mixture of Ethylenediamine/water this solution was filtered p is at room temperature. Clear filtrate was used as the initial solution of silver/amine for the preparation of the catalyst.

b. Adding promoter

Transparent original solution was diluted with a mixture of ethylenamine/water 64/34. Then the hydroxide Cs and hydrosulphate of ammonia was added to dilute the silver solution to prepare a catalyst containing 11% silver and a suitable amount of cesium and sulphur.

C. the Impregnated catalyst

A sample of 150 g of the carrier was placed in the autoclave and then was pumped until the pressure was reduced to 50 mm Hg 200 ml of the prescribed solution of silver/promoters were introduced into the flask while it was still under vacuum. The pressure in the vessel was allowed to rise to atmospheric pressure and the contents were shaken for several minutes. The catalyst was separated from the solution, and now he was ready for roasting.

d. The calcination of the catalyst

The annealing, deposition of silver caused by heating the catalyst to a temperature of decomposition of silver salts. This was achieved by heating in an oven that has multiple heating zones in a controlled atmosphere. The catalyst was placed on a moving tape, which was a part of the furnace at ambient temperature. The temperature was gradually increased as the catalyst passed from one zone to the next. It was increased to 400°C, when catalyzatoroprovod through seven heating zones. After heating zones tape is passed through a cooling zone, which was gradually cooled catalyst to a temperature lower than 100°C. the total time of stay in the furnace was 22 minutes. The atmosphere of the furnace was regulated by using a stream of nitrogen in the different heating zones. This catalyst is designated catalyst 3.

C. Testing of catalyst

The catalysts were tested in a stainless steel tube which was heated by using a bath of molten salt. The source gas mixture containing 15% ethylene, 7% oxygen and 78% inert gas, mainly nitrogen and carbon dioxide, used for testing catalysts at 300 psig. The reaction temperature was tuned to obtain the standard performance for ethylene oxide 160 kg per hour per m³catalytic Converter.

EXAMPLE 12

Media A-N used for the preparation of catalysts for the oxidation of ethylene to ethylene oxide by the procedure illustrated in example 11. The results of the testing of the catalysts are summarized in table.

Although the present invention specifically shown and described with reference to preferred embodiments of the specialists in the art will understand that various changes and modifications can be made without deviating from the essence and scope of this izaberete the Oia. It is understood that the invention encompasses data described embodiments of the alternatives discussed above and all equivalents thereto.

1. Composition to obtain a catalyst carrier, which includes a mixture of at least one alpha alumina having an average particle size of about 5 μm or more in an amount of from about 20 wt.% to about 40 wt.% of the total content of alumina in the composition; at least one hydrated precursor of alpha alumina in an amount of from about 60 wt.% to about 80 wt.% of the total content of alumina in the composition; a binder and a foaming agent.

2. The composition according to claim 1, where at least one hydrated precursor of alpha alumina contains aluminum hydroxide.

3. The composition according to claim 2, where at least one aluminum hydroxide selected from the group consisting of gibbsite, boehmite, Diaspora, bayerite and their combinations.

4. The composition according to claim 1, where the composition contains almost no iron oxide, chromium oxide and particles of alpha alumina submicron size.

5. The composition according to claim 1, additionally containing water in an amount sufficient to make the composition is extrudable.

6. The composition according to claim 1, where the binder contains a material selected from the group status is the present of thermally-degradable organic compounds, clays, silicon oxides, silicates of group elements of the Periodic system of elements and their combinations.

7. The composition according to claim 1, where the binder contains a material selected from the group consisting of poliolefinas, oils, gum Arabic, carbon, cellulose, substituted cellulose, ethers of cellulose, stearates, waxes, granular polyolefin, polystyrene, polycarbonate, sawdust, crushed walnut shell powder, silicon oxide, salt of an alkali metal and combinations thereof.

8. The composition according to claim 1, where the composition further comprises one or more components selected from the group consisting of talc, water-soluble compounds of titanium, grease, combustible material, and combinations thereof.

9. The composition according to claim 1, where the foaming agent allocates gas under the application of sufficient heat.

10. The method of receiving the catalyst carrier, including:
a) a composition comprising a mixture of at least one alpha alumina having an average particle size of about 5 μm or more in an amount of from about 20 wt.% to about 40 wt.% of the total content of alumina in the composition; at least one hydrated precursor of alpha alumina in an amount of from about 60 wt.% to about 80 wt.% of the total content of alumina in the composition; a binder and foam is OBRAZOVATEL;
b) forming the resulting composition into the structure; then
c) heating the above-mentioned structure for a sufficient time and at sufficient temperature to produce a porous structure; and then
d) heating this porous structure for a sufficient time and at sufficient temperature to convert the intermediate alumina in the porous sintered structure of alpha aluminum oxide.

11. The method according to claim 10, where step C), step d), or both steps (C) and (d) is performed in the atmosphere of inert gas and, optionally, an oxidizing gas.

12. The method of producing catalyst intended for oxidation of ethylene to ethylene oxide, which includes:
obtaining a catalyst carrier by the method according to claim 10 and then
e) deposition of a catalytically effective amount of silver on the surface of the specified catalyst carrier.

13. The method according to item 12, which further includes the deposition promoting amount of a promoter to the surface of the catalyst carrier, and this promoter contains one or more compounds containing alkali metals, one or more compounds containing transition metals, one or more sulfur components, one or more components containing fluorine, or combinations thereof.

14. The method of receiving the catalyst carrier, including:
a) getting to the position, comprising essentially at least one hydrated precursor of alpha alumina; binder and a foaming agent; then
b) forming the resulting composition into the structure; then
c) heating the above-mentioned structure for a sufficient time and at sufficient temperature to produce a porous structure, and then
d) heating this porous structure for a sufficient time and at sufficient temperature for the conversion of the hydrated precursor of alpha alumina in the porous sintered structure of alpha aluminum oxide.

15. The method according to 14, where the step C), step d), or both steps (C) and (d) is performed in the atmosphere of inert gas and, optionally, an oxidizing gas.

16. The method of producing catalyst intended for oxidation of ethylene to ethylene oxide, which includes:
obtaining a catalyst carrier by the method according to 14, and then
e) deposition of a catalytically effective amount of silver on the surface of the catalyst carrier.

17. The method according to clause 16, which further includes the deposition promoting amount of a promoter to the surface of the catalyst carrier, and this promoter contains one or more compounds containing alkali metals, one or more compounds containing transition metals, one or more sulfur comp is required, one or more components containing fluorine, or combinations thereof.

18. The catalyst used for oxidation of ethylene to ethylene oxide obtained according to item 13 or 17.

19. The method of oxidation of ethylene to ethylene oxide, which includes gas-phase oxidation of ethylene with molecular oxygen in a tubular reactor with a fixed bed in the presence of a catalyst obtained according to item 13 or 17.