MXPA97005608A - Alkylene oxide catalyst and proc - Google Patents

Abstract

The present invention relates to a catalyst for the epoxidation, or conversion to epoxide, of olefins that do not have hydrogen, allylic, in particular ethylene, with molecular oxygen, the catalyst is characterized in that it comprises a catalytically effective amount of silver and a promoter amount of an alkali metal, optionally a rhenium promoting amount and optionally a promoter amount of a rhenium copromotor, deposited on a carrier or support which is prepared by a process comprising mixing ceramic components in the form of particles, with an amount of 0.5 by weight to 50 parts by weight, based on 100 parts by weight of the ceramic components, of polypropylene, in the form of a powder having an average particle size of less than 400 microns and an ash content of less than 0.1% in weight, and then bake or bake at a temperature sufficient to burn the synthetic organic polymer, sinter the component in the form of particles and form a carrier or torpor

Description

CATALYST OF ALKYLENE OXIDE AND PROCESS FIELD OF THE INVENTION The present invention relates to catalysts containing silver, suitable for the preparation of alkylene oxide, in particular, ethylene oxide, and to the use of catalysts. The catalysts are prepared using a catalyst carrier, ceramic based, unique in its kind.

BACKGROUND OF THE INVENTION The catalysts for the production of ethylene oxide, from ethylene and from molecular oxygen are generally supported silver catalysts. These catalysts are typically promoted with alkali metals. The use of small amounts of the alkali metals potassium, rubidium and cesium was noted, as useful promoters in silver catalysts, in U.S. Patent No. 3,962,136, issued June 8, 1976, and in U.S. Patent No. 4,010,115 issued on 1 REF: 25209 March 1977. The use of other copolymers, such as rhenium, or rhenium in conjunction with sulfur, olibdene, tungsten and chromium, is described in U.S. Patent No. 4,766,105, issued August 23, 1988, and in U.S. Patent No. 4,808,738, issued February 28, 1989. U.S. Patent No. 4,908,343, issued March 13, 1990, discloses a supported silver catalyst containing a mixture of a cesium salt and one or more alkali metals and alkaline earth metal salts. The North American patent No. 4,897,498, issued on January 30, 1990, describes the use of supported catalysts, based on silver, promoted with alkali metals, in epoxidation, or epoxide conversion, of olefins having nonalicylic hydrogens. The use of catalyst carriers, based on porous ceramic, has been previously described in a number of patents such as for example Patent No. 5,100,859 issued March 31, 1992, US Patent No. 5,055,442, issued on 8 October 1991. U.S. Patent No. 5,037,794 issued August 6, 1991, and U.S. Patent No. 4,874,739 issued October 17, 1989. These catalyst carriers have a wide variety of potential applications in the catalytic field and are especially useful where the ceramic base is an alumina such as alpha alumina. Although alpha alumina is often the ceramic base of the preferred catalyst, it is understood that other ceramic materials, such as silica, silicon carbide, silicon nitride, magnesia, titania, spinel and cordierite, as well as other forms may be used. of alumina. In further discussions catalysts based on alpha alumina are used as examples, but it is understood that the description herein has a more general application.

A catalyst support needs to have, in combination, at least a minimum surface area on which the catalyst component can be deposited, high water absorption and crushing resistance. Often an increase in one property means a reduction in another. Thus, a high crushing resistance can mean low porosity. Usually the balance is achieved by trial and error, making the technique of catalyst carriers even more unpredictable than other techniques of chemical processes. Carriers need to have a uniform degree of porosity and this can be achieved in a number of ways including the incorporation of combustible materials that are removed when the pottery is burned, to form the finished product. Typical combustible materials include charcoal, petroleum coke, walnut shells and the like. These materials usually leave leachable residues that can significantly impair the performance or operation of the supported catalyst on the carriers. In addition, the actual content of these leachable residues varies widely from one batch to another, so that the predictability is unsatisfactory. There is therefore a need to design catalysts in which one can have certainty with respect to the balance of final properties. The catalysts of the present invention have a balance of crushing strength, abrasion resistance, porosity and catalytic performance, which make them ideal for a wide range of catalytic applications.

The invention relates to a catalyst suitable for the epoxidation of olefins which do not contain allylic hydrogen, in particular ethylene, with molecular oxygen, in the vapor phase, the catalyst comprises a catalytically effective amount of silver, an alkaline-promoting amount, optionally a rooting promoter amount and optionally a promoter amount of a rhenium copromotor supported on a carrier prepared by a process comprising mixing ceramic components in the form of particles, with an amount of 0.5 to 50 parts by weight, based on 100 parts by weight. weight of the ceramic components, of a synthetic organic polymer, in the form of a powder having an average particle size of less than 400 microns and an ash content of less than 0.1% by weight, and then cooking at a temperature sufficient to burn the synthetic organic polymer, sintering the component in the form of particles and forming a carrier. The carrier material thus prepared has a low content of leachable metal compounds. As used herein, "lixible metal compounds" refers to impurities of sodium, potassium, calcium and / or aluminum resulting from the burned material. As used herein, "leachable compounds" refers to the sum of the leachable metal compounds plus the contributions of other additives, some of which may impart desired characteristics to the carrier and / or the catalyst. It has been found that catalysts having this ceramic-based carrier, unique in their kind, have improved physical properties relative to catalysts having conventional carriers. These catalysts have improved crushing resistance and abrasion resistance. Below are cor. detail the descriptions of the carrier, the catalyst prepared with the carrier and the u or "of the catalyst.

The Porter The amount of leachable compounds is measured by boiling a standard or standard amount, of the finished carrier, in a standard volume of 10% nitric acid, for 30 minutes. This extracts the metal components in the form of the soluble nitrates that can then be separated and analyzed with respect to the values of residual metal compounds. By this method you can also extract some silica but this is not considered for the purposes of this exercise due to the variable contribution made by the ceramic and bonding components. The amount of leachable metal compounds that remain after burning the carrier, to remove the combustible material based on synthetic organic polymer, and which result from the same, is desirably less than 2,000 ppm, preferably less than 1,500 ppm, and in the form more preferred, less than 1,000 ppm, expressed in terms of the amount of leachable metal in the finished carrier. In a preferred process for preparing the catalyst carrier, of the present invention, the polymer particles have an average particle size, which is from 5 to 400, and more preferably from 10 to 300, and in most preferred form from 15 to 200 micrometers. The polymeric particles can have any desired configuration, but since the objective is to produce a carrier material, with a high but uniform porosity, this is achieved in the most efficient way if the particles have a configuration, in general block (which is the closest to the spherical). The porosity is also greatly influenced by the particle size of the particles of the ceramic material of which it is made. Indeed, often these particles and their sizes are the dominant factors, and the particle size of the combustible material has only a marginal effect on the porosity. The polymer can be any of those that are exclusively organic and does not contain significant amounts of residual inorganic material., as a result of the method by which it was manufactured. The polymers can be formed using an emulsion polymerization or bulk polymerization process, which includes suspension polymerization, which is often preferred since the polymer can be obtained in the form of very fine particles that can be used directly. in the process of preparation of the carrier, of the invention. Although these fine particles can be easily obtained by these techniques, they can also be provided by conventional crushing techniques.

Suitable polymers include olefinic polymers such as polyethylene, polypropylene, vinyl acetate and ethylene vinyl alcohol; the diene polymers and copolymers, such as polybutadiene, EPDM rubber, styrene-butadiene-acrylonitrile copolymers; polyesters such as nylon 6, and nylon 66, polyesters such as polyethylene terephthalate and vinyl polymers such as styrene polymers. Preferred particulate materials are hydrocarbon polymers, such as polyolefins and particularly polypropylene. Polymeric, synthetic, organic combustible materials can also be used in combination with smaller amounts of conventional, combustible materials, where the need to have leachable compounds in a very small amount is not so great, and smaller amounts of the residual compounds. The combustion products formed by burning the polymer are preferably non-toxic and non-corrosive. For this reason, polymers comprising a halogen, nitrogen or sulfur atom are generally less preferred. Combustible materials, when burned, leave other materials that are commonly referred to as "ash" and this is used as a measure of the amount of leachable metal compounds left in a ceramic material left after combustion. The amount of ash and leachable metal material is fairly constant for any combustible material based on particular organic polymer, and this is a significant advantage. There may be no exact correspondence between the ash content and the amount of leachable compounds in the carrier, in view of the potential contribution to the content of leachable compounds, of other components of the composition, of which the carrier is formed, and include surfactants, temporary binders, bonding materials, etc., and the like; These latter components are usually and preferably chosen with specific premeditated properties and the leachable compounds that arise are accepted as an inevitable consequence. If the leachable metal compounds with which the combustible material contributes vary widely, as is the case with traditional combustible materials, such as walnut shells, the total leachable compounds can vary unpredictably and can often exceed the preferred maximum. The use of a combustible material with a known and stable amount of leachable metal compounds allows the selection of other components of the composition to establish a level of leachable metal compounds which will not exceed the maximum level desired.

As indicated above, is it possible? define the preferred combustible material, tañí-in terms of the ash residue when burned, or in terms of the leachable metal compounds that can be extracted from the finished carrier. In the case of ash content, the amount should be minimized clearly as much as possible and a maximum level of 0.1% by weight is preferred. A maximum level of 0.05% is most preferred.

The material from which the carrier is manufactured is not critical, and any carrier based on ceramic can be adapted for use in combustible, polymeric, organic materials. The carrier can be, for example, a carrier based on alumina, of the type described in U.S. Patent Nos. 5,266,548; 5,100,859; 5,055,042. Alternatively, it may be based on silica, aluminosides, cordierites, zirconia, spinels, magnesia, or titania, as well as combinations of these materials. Preferably, it is based predominantly (ie at least 90% by weight of the ceramic components) on alumina and particularly on alpha alumina, although lower amounts of other ceramic oxides (calcite, magnesia, strontium, titania and zirconia) may be present. , or silicates. An example of a process for the production of the catalyst carriers, based on alumina, preferred of the invention, comprises: (i) Form a mixture comprising: (a) at least one alumina component in the form of particles; (b) from 0.5 to 50% based on the weight of the total ceramic components, of a combustible, organic, synthetic material, having an ash content of less than 0.1%; and (c) water in sufficient quantity to extrude the above mixture; (ii) extruding the mixture and obtaining the desired forms; (iii) firing until sintering the alumina particles, to produce a porous carrier based on alumina, with a surface area of 0.40 to 5.0, and preferably of 0. 40 1.5 m / g and less than 2,000, preferably less than 1500 ppm, of leachable metal compounds.

The catalyst carrier of the present invention may comprise a number of alumina components and optionally other ceramic-forming components, chosen to contribute to the desired physical or physical properties including porosity, volume of pore, resistance to crushing and the like. A combination of two different alpha-aluminas is often preferred, where a component having larger particles is mixed with a second component having smaller particles, in weight ratios of 10:90 and 90:10. The objective of this is to obtain a surface area in the finished product of 0.4 to 5 m / g. As used herein, "surface area" means the BET surface area measured using nitrogen or krypton as the adsorbed gas. The surface area in the finished carrier is somewhat smaller than for the free alumina particles. Thus, a suitable mixture may comprise, for example, two types of alpha alumina particles, the first with a surface area of approximately 1 m / g and the second with a surface area of approximately 3 to 5 m / g. Often other components, such as titania, can confer a particular advantage to these carrier materials. Porous carriers, preferred, based on alpha alumina, for the catalyst of the present invention, have a content of leachable metal components, below 2,000 ppm. In comparison with a carrier having the same porosity and packed density, manufactured using the same ceramic components and with combustible, organic, non-polymeric, conventional or traditional materials, these present a wear, which is at least 10%, and preferably of at least 20%, lower, and a resistance to grinding that is at least 10%, and preferably at least 20%, more at ta. The final carrier, calcined, preferably has a porosity of at least 50% and more desirably ie 60% to 75%, a crushing strength of at least 2.3 kilograms (5 pounds), and a packed density, seated, of at least 0.5 kilograms per liter, preferably at least 0.6 kilograms per liter. The surface area of the calcined final carrier is preferably 0.4 to 5, preferably 0.6 to 1.5 m / g. It is often advantageous to add titania to the mixture to be extruded, in an amount representing from 0.05% to 5.0%; preferably from 0.05% to 2.0%, and more preferably from 0.08% to 1% of the weight of the cooked carrier. Certain forms of alumina and binder material may also contain titania as impurities or components. The contribution of these forms of titania are not included in the amounts specified above. The titania can be added as the dioxide, as a titanate or as a precursor of titania. In the following description it is understood that all the above options will be included under the term "titanias". Other materials such as zirconia or magnesia can also be used. The carrier alumina components can also be mixed. with a binding agent and water, give them certain shapes and calcinate them. The term "binding agent", such cope is used herein, refers to an agent that holds the different carrier components together, after they have been given a final form, either by extrusion or by forming small pieces. These binding agents allow the formed materials to dry and burn without crumbling. These binding agents are usually "sticky" and are organic materials such as polyvinyl alcohols or cellulosic materials. The binding agents can also be used as auxiliaries in the extrusion. In certain cases, peptizing acids can be used instead of binding agents.

It is usually preferred to add a ceramic binder material to the mixture to provide additional resistance to the cooked carrier. Conventional, ceramic bonding materials are typically present in an amount of 0.01% by weight to about 5%, based on the total weight of the ceramic components expressed as the oxides. The bonding materials, ceramic, conventional, can be used before and after cooking. These materials typically comprise components (expressed as oxides) such as silica, alumina, alkali metal oxides, alkaline earth metal oxides, alkaline earth metal silicates, iron oxide and titanium oxide.

After the components of the carrier are mixed together, say by kneading, the mixed material is extruded into small pieces having a certain shape, for example, cylinders, rings, trilobes, tetrallobes and the like. To facilitate extrusion, "extrusion aids" such as Gelatinous Petroleum Vaseline and other organic lubricating materials can be used. The extruded material is dried to remove water that could become steam during calcination and destroy the extruded forms. After drying to a low water content, ie at least about 2%, the extruded material is calcined under conditions sufficient to remove the combustion agents, the extrusion aids and the binding agents, and to melt the particles of alpha alumina and provide a hard and porous mass. Calcination is typically carried out in an antioxidant atmosphere, namely oxygen gas or preferably air and at a maximum temperature greater than 1,300 ° C and preferably ranging from about 1,350 ° C to about 1,500 ° C. Times at these maximum temperatures typically range from about 0.1 to 10 hours, preferably from 0.5 to 5 hours. The calcined carriers and catalysts made therefrom will typically have pore (water) volumes ranging from about 0.2 to about 0.6 cc / g, preferably from about 0.3 to 0.5 cc / g, and surface areas ranging from about 0. 15 to about m / g, preferably from about 0.3 to about 2 m / g. The carrier formulation preferably has a low soda content that is less than about 0.06% by weight. In practice it is very difficult to obtain a sodium-free formulation and soda contents from about 0.02% to 0.06% by weight, usually found as acceptable.

The carriers described above are particularly convenient for preparing ethylene oxide catalysts having improved physical properties with respect to crushing strength and abrasion resistance.

The catalyst The catalysts of the present invention comprise a catalytically effective amount of silver and a promoter amount of alkali metal (s) deposited on a carrier prepared by a process as described above. Other promoters in promoter amounts, such as rare earth elements, magnesium, oar and rhenium copromoters selected from sulfur, chromium, molybdenum, tungsten, phosphorus, and mixtures thereof, may also be present, optionally, in promoter amounts. In general, the catalysts of the present invention are prepared by impregnating porous, refractive supports comprising alpha alumina, with ions or compound (s), complex (s) and / or silver salt (s), dissolved in a solvent suitable, sufficient to cause deposition on the support, from one to 40, preferably from 1 to 30% by weight, based on the weight of the total catalyst, of silver. The impregnated support is then separated from the solution and the deposited silver compound is reduced to metallic silver. Also deposited on the support, either before, co incidentally, or subsequent to, the deposition of the silver, will be the ions, or compound (s) and / or alkali metal salt (s), suitable, dissolved in a solvent suitable. Also deposited on the carrier, coincidentally with the deposition of the silver and / or alkali metal, will be found a suitable compound (s), complex (s) and / or salt (s) promoter (s), optional (s), ( s), dissolved in an appropriate solvent.

The catalysts of the present invention are prepared by a technique in which the alkali metal promoter, as well as any additional promoters, in the form of soluble salts and / or compounds, is deposited on the catalyst and / or support before, simultaneously, or subsequently to, li deposition of the silver and each of the other components. The preferred method is to deposit silver and alkali metal, simultaneously, on the support, that is, in a single impregnation step, although it is believed that the individual or concurrent deposition of the alkali metal before and / or subsequent to the deposition of silver, would also produce suitable catalysts.

Alkali metal promoting amounts or alkali metal mixtures are deposited on a porous support using a suitable solution. Although alkali metals exist in a pure metallic state, they are not suitable for use in that form. They are used as ions or alkali metal compounds dissolved in a suitable solvent for impregnation purposes. The carrier is impregnated with a solution of ions, salt (s) and / or promoting compound (s), of alkali metal, before, during or after the impregnation of the ions or salt has taken place. ), complex or (is), and / or compound (s), silver. You can even deposit an alkaline metal promoter on the carrier, after the metal silver reduction has taken place. The amount of alkali metal promoter used will depend on several variables, such as, for example, the surface area and structure of the pore and chemical properties of the surface of the carrier used, the silver content of the catalyst and the particular ions used in conjunction with the catalyst. the alkali metal anion, and optional co-promoters. The amount of alkali metal promoter, deposited on the support, or present on the catalyst, is generally between 10 and 3,000 preferably between 15 and 2,000, and more preferably between 20 and 1,500 parts per million, per weight of the total catalyst . Most preferably, the amount varies between 50 and 1,000 parts per million by weight of the total catalyst. For purposes of convenience, the amount of alkali metal deposited on the support or present on the catalyst is expressed as the metal. Without intending to limit the scope of the invention, it is believed that the alkali metal compounds are oxidic compounds.

In a preferred embodiment, at least a major or major portion (greater than 50% by weight) of the alkali metals are selected from the group consisting of potassium, rubidium, cesium and mixtures thereof. A preferred metal-alkaline promoter is cesium. A particularly preferred alkali metal promoter is cesium plus at least one additional alkali metal. The additional alkali metal is preferably selected from. sodium, lithium and mixture thereof, with lithium being preferred. When a lithium compound is used, such as the additional alkali metal, the amount used is typically in the range of 40 to 150, and preferably in the range of 40 to 100 micromoles per gram, based on the total weight of the catalyst. The catalyst may also contain moderate amounts of chloride, for purposes of increasing the activation or start-up procedure for the catalysts. When chloride is added to the catalyst, the carrier may be impregnated with a solution of ions, salt (s) and / or compound (s), moderators, containing chloride, before, during or after the impregnation of the ions or salt (s), complex (s), and / or compound (s), silver, and before, during or after the impregnation of the ions or salt (s), complex (s) has taken place, and / or compound (s), of promoter ions. The chloride moderator can be deposited even on the carrier, after metallic silver has taken place. The salts that contain chlorideSuitable, used to prepare the impregnation solutions, include the promoter chlorides such as lithium chloride, sodium chloride, potassium chloride, rubidium chloride and cesium chloride, as well as ammonium chloride. Ammonium chloride is a preferred salt for use in the preparation of chloride-containing impregnation solutions. Other compounds which decompose to give the chloride ion during the processing of the catalyst are also suitable. Impregnation solutions, which contain chloride, will ordinarily contain at least a small amount of water to increase the solubility of the salt or chloride-containing compound. Other promoters and co-promoters can be used in conjunction with silver and alkali metal promoters.

Non-limiting examples of other promoters include rhenium, sulfate, molybdate, tungstenate and chromate (see U.S. Patent No. 4,766,105, issued August 23, 1988) as well as phosphate and borate; sulfate anion, fluoride anion, oxyanions, from groups 3b to 6b (see U.S. Patent No. 5,102,848 issued April 7, 1992); (i) oxyanions of an element selected from the groups 3 to 7b and (ii) alkali metal salts with halide anions, and oxyanions selected from the groups 3a through 7a and 3b through 7b (see US Pat. No. 4,908,343 issued March 13, 1990).

Generally, the carrier is contacted with a silver salt, with a silver compound or with a complex of avocado, which has been dissolved in an aqueous solution, in such a way that the carrier is impregnated with that aqueous solution, then the The impregnated carrier is separated from the aqueous solution, for example, by centrifugation or filtration, and then dried. The impregnated carrier, thus obtained, is heated to reduce the silver to metallic silver. It is conveniently heated up to a temperature which is in the range of 50 ° C to 600 ° C for a sufficient period to cause the reduction of the salt, compound or complex, of silver, to metallic silver, and to form a finely divided silver plate, which is attached to the surface of the carrier, both on the outside and on the surface of the pore. During this heating step, air, another oxidant gas, a reducing gas, an inert gas or mixtures thereof can be conducted through the carrier.

There are several known methods for adding silver to the carrier or support. The carrier can be impregnated with an aqueous solution containing silver nitrate dissolved therein, and then dried, after which the silver nitrate is reduced with hydrogen or hydrazine. The carrier can also be impregnated with an ammonia solution of silver oxalate and silver carbonate and then dried, and after that drying step the silver oxalate or silver carbonate is reduced to metallic silver by heating, for example, to 600 ° C. As such, specific solutions of silver salts can be used, with solubilizing and reducing agents, for example combinations of vicinal alkanolamines, alkylenadiamines and ammonia. An example of a silver salt solution comprises an impregnation solution comprising a silver salt of a carboxylic acid, a solubilizing / reducing agent, based on organic mine, and an aqueous solvent. Suitable silver salts include silver carbonate and silver salts of hydroxycarboxylic and carboxylic acids, monobasic and polybasic, of up to about 16 carbon atoms. Silver carbonate and silver oxalate are particularly useful silver salts, and silver oxalate is the most preferred. A solubilizing / reducing agent based on organic amine is present in the impregnation solution. Suitable solubilizing / reducing agents of the silver, based on organic amine, include the lower alkylenediamines of 1 to 5 carbon atoms, mixtures of a lower alkanolamine of 1 to 5 carbon atoms, as well as mixtures of ammonia with lower alkylene diamines or lower alkylene diamines of 1 to 5 carbon atoms. Particularly useful are 4 groups of lubricating / reducing agents based on organic amine. The 4 groups include the vicinal alkylene diamines of 2 to 4 carbon atoms, mixtures of vicinal (1) alkylene diamines of 2 to 4 carbon atoms and (2) vicinal alkylene diamines of 2 to 4 carbon atoms, mixtures of vicinal alkylene diamines of 2 to 4 carbon atoms and ammonia, and mixtures of vicinal alkylenediamines of 2 to 4 carbon atoms and ammonia. These solubilizing / reducing agents are generally added in the amount of from about 0.1 to about 10 moles per mole of silver present.

In US Pat. No. 3,702,259 a method for preparing the silver-containing catalyst can be found. Other methods for preparing the silver-containing catalysts, which also contain higher alkali metal promoters, can be found in the U.S. patent No. 4,010,115 and in the North American patent No. 4,356,312; in the North American patent No. 3,962,136 and in the North American patent No. 4,012,425. In North American Patent No. 4,761,394, methods of higher silver-containing catalysts containing rhenium and alkali metal promoters can be found, and in US Pat. No. 4,766,105 methods for silver-containing catalysts containing promoters can be found. of rhenium and alkali metals, higher, and rhenium copromoters. US Pat. Nos. 4, 908, 343 and 5,057,481 disclose methods for preparing silver-containing catalysts with a variety of different promoters.

A particularly preferred process for impregnating the carrier is to impregnate the carrier with an aqueous solution containing a silver salt of a carboxylic acid, an organic amine and a cesium salt and a salt of an additional alkali dissolved therein. A preferred salt is silver oxalate. It can be prepared by reacting silver oxide (aqueous paste) with (a mixture of et i lend sheet and oxalic acid, or (b) oxalic acid and then the etherendiamine, the latter being preferred, so that an aqueous solution of the latter is obtained. complex of silver oxalate-ethylene amine, solution to which a certain amount of a compound of cesium and a certain amount of additional alkali metal is added, other diamines and other amines such as ethhalonamine can be added as such. prepare a solution of oxalate of silver containing cesium, precipitating the oxalate of silver from a solution of oxalate of cesium and silver nitrate, and rinsing with water or alcohol the oxalate of silver obtained, to eliminate the cesium salt adhered until the desired cesium content is obtained, then the oxalate containing cesium is solubilized with ammonia and / or an amine in water. s containing rubidium, potassium, sodium, lithium and mixtures of solutions containing alkali metals. The impregnated carriers are then heated to a temperature which is between 50 ° C and 600 ° C, preferably between 75 ° C and 400 ° C, to evaporate the liquid to produce a metallic silver.

The process On a commercial scale, the ethylene and oxygen are converted into ethylene oxide, into a reactor for ethylene oxide comprising a large fixed tube heat exchanger, containing several thousand tubes filled with catalysts. A coolant is used on the reactor shell side to remove the heat of reaction. Coolant temperatures are often used as an indication of catalyst activity, and high temperatures in the coolant correspond to low catalyst activities.

In the reaction of ethylene with oxygen, to produce ethylene oxide, ethylene is typically present at least in a double amount (on a molar basis) compared to oxygen, but the amount of ethylene employed is generally much higher. The conversion is therefore conveniently calculated according to the molar percentage of oxygen that has been consumed in the reaction to form ethylene oxide and any oxygenated byproducts. The conversion of oxygen is dependent on the reaction temperature and the reaction temperature is a measure of the activity of the catalyst used. The value T o indicates the temperature at 40% conversion of oxygen in the reactor and the value T is expressed in ° C and the value Ti.5 indicates the temperature at 1.5% of production of ethylene oxide. This temperature for any given catalyst is higher when the conversion of oxygen is greater. further, this temperature is strongly dependent on the catalyst used and the reaction conditions. The selectivity (to ethylene oxide) indicates the molar amount of ethylene oxide in the reaction product, compared to the total molar amount of ethylene converted. In this specification, the selectivity is indicated as S40, which means the selectivity at 40% oxygen conversion, or as Si.5, which means the selectivity at 1.5% ethylene oxide. The conditions for carrying out that oxidation reaction, in the presence of the silver catalysts according to the present invention, comprehensively comprise those already described in the prior art. This applies, for example, to suitable temperatures, pressures, residence times, to diluting materials such as nitrogen, carbon dioxide, steam, argon, methane or other saturated hydrocarbons, in the presence of moderating agents to control the catalytic action, For example, 1,2-dichloroethane, vinyl chloride, ethyl chloride or polyphenyl compounds, chlorinated, at the desire to employ recycling operations or apply successive conversions in different reactors to increase the yields of ethylene oxide, and any other special conditions that can be selected in the process to prepare the ethylene oxide. Generally, pressures in the range of atmospheric pressure to about 35.15 kg / cm (500 psig) are employed. However, higher pressures are not excluded. Molecular oxygen can be obtained as reagent from conventional sources. The proper oxygen charge may consist of essential or relatively pure oxygen, a concentrated oxygen stream comprising oxygen in greater quantity with smaller amounts of one or more diluents, such as nitrogen and argon, or another stream containing oxygen such as air . It is therefore evident that the use of the silver catalysts of the present invention, in the creation of ethylene oxide, is in no way limited to the use of specific conditions among those which are known to be effective. For purposes of illustration only, the following table shows the range of conditions that are often used in commercial, common units of a reactor for ethylene oxide and that are also suitable for the use of ethylene oxide.

TABLE I * GHSV 1,500 - 10,000 Input pressure 1,000 - 3,500 kPa Input feed Ethylene 1 - 40% 02 3 - 12% Ethane 0 - 3% Moderator 0.3-50 ppmv total hydrocarbon Diluent of argon The rest and / or methane and / or nitrogen Reagent temperature 180 - 315 ° C Catalyst temperature 180 - 325 ° C Conversion level 0 10 - 60% OE production (Rate 32 - 320 kg OE / sf work) Catalyst / h * Volume "of gas at standard temperature and pressure, which passes through a volume of catalyst packed per hour.

In a preferred application of the silver catalysts, according to the invention, ethylene oxide is produced when an oxygen-containing gas is contacted with ethylene, in the presence of the catalysts of the present invention, at a temperature that is is in the range of about 180 ° C to about 330 ° C, and preferably a temperature that is in the range of about 200 ° C to about 325 ° C. Although the catalysts of the present invention are used to convert ethylene and oxygen to ethylene oxide, the olefins which do not have alane hydrogens can be oxidized using the avocado catalysts of the present invention, to produce a high selectivity of epoxide derivatives of the same, by contacting the aliphatic allylation with a gas containing oxygen, in the presence of an organic halide and the catalyst of p 1 at. described above under the defined oxidation conditions. The olefins contemplated for the use e:. this oxidation process, are those that satisfy the following structural formula: wherein each R is independently selected from the group consisting of: (a) hydrogen, (b) aryl groups and substituted aryl groups which are in the range of 6 to 20 carbon atoms, (c) alkyl groups of the formula: Where each R 'is independently ,. «-, .- L wherein R "is H, alkyl of 1 to 10 carbon atoms, or substituted alkyl, a substituted aryl group having from 6 to 20 carbon J atoms and n is an integer of 0 12 (d) CR3"- (CR2")? -0-, wherein x is an integer from 1 to 12; (and) R. • L. (f) R2"N-; (g) R" S-; (h) CR2"= CR" - (-CR "= CR" -) -y, where y is an integer of 0-20 and (i) wherein X is 0, S and NR "; and m is an integer from 0 to 3 with the proviso that said olefin does not have ring hydrogens and that at least one group is not hydrogen. Exemplary olefins satisfying the above structural formula include butadiene, tertiary butylethylene, vinylfuran, methyl vinyl ketone, N-vinyl pyrrolidone, and the like An olefin preferred herein, for the use in practice of this process is butadiene because of its ready availability, relatively low cost, and the wide range of possible uses for the product of the epoxide reaction The epoxides produced by this process have the structural formula: where each R is defined independently as previously stated. Where one or more of the R groups contain unsaturation in the carbon-carbon bonds, further oxidation may be carried out, thereby producing polyepoxide products. The process is carried out by contacting the olefin to be oxidized with molecular oxygen and an organic halide, under the oxidation conditions, ie in the presence of sufficient quantities of an oxygen-containing gas, to provide a molar ratio from olefin to oxygen, which is in the range of 0.01 to 20, and in the presence of 0.1 to 1,000 parts per million (per volume of total feed) of organic halide. Preferred amounts of organic halide, for use in the practice of the present invention, are within the range of 1 to 100 parts by volume of the total feed. Suitable gases containing oxygen include air, air enriched with oxygen, substantially purified oxygen, oxygen diluted with inert gases, such as N2, Ar, CO2, CH4 and the like. Suitable reaction temperatures fall within the range of 75 ° C to 325 ° C. The preferred reaction temperatures fall within the range of! 25 ° C to 295 ° C; and temperatures that are within the range of 175 ° C to 290 ° C are most preferred because the selectivity to the desired epoxide decreases to temperatures significantly above about 290 ° C and the yields are sparingly they are undesirably low at temperatures below about 175 ° C. The reaction pressure can vary within wide ranges, and typical limits of 0.1 to 100 atmospheres are chosen primarily as a function of safety, handling, equipment, and other practical considerations. Preferably, the reaction pressure is maintained in the range of 1 to 30 atmospheres. Reaction times, suitable for this process, can vary within wide ranges. Generally, the olefin, oxygen, organic halide and catalyst are kept in contact for a sufficient time to obtain conversions of the olefin, per step, which are in the range of 0.1 to 75 mole percent. The target, preferred levels, and the conversion of the olefin, by step, c a e r. within the range of 1 to 50 percent er. mol, while the reaction times. enough to obtain a 1-olefin conversion, per step, found in. : range from 5 to 30 percent mol, sor. most preferred in the present for the efficient utilization of the capacitance of the reactor. The experts in the art recognize that the actual contact times, required to achieve the desired conversion levels, can vary within wide ranges, depending on factors such as the size of the vessel, the olefin to oxygen ratios, the level of silver loading on the catalyst, the presence or absence of some catalyst modifiers (and their charge levels), the amount of organic halide present in the reaction zone, the reaction temperature and pressure, and the like. The process can be carried out either in continuous mode or in batch mode. In the present, the continuous reaction is preferred since in this way high costs are obtained in the reactor and a product of high purity. The batch mode is used successfully when high volumes and reagent costs are not required, for example, for liquid phase reactions. For the continuous reaction mode carried out in the gas phase, the typical gas velocity space per hour (GSHV) values, fall within the range of 100 to 30,000 h - 1, prefer GHSV values that are in the range of 200 to 20,000 h_1, and GHSV that are in the range of 300 to 10,000 h ~ are most preferred because under these conditions the most desirable combination of olefin conversion fed and selectivities are obtained by the product. When the continuous mode of reaction is carried out in the liquid phase, the typical values of space velocity per hour of liquid (LHSV) employees, will give contact times analogous to those obtained from GHSV previously presented. Most preferably, the GHSV presented previously. Most preferably, the LHSV will be in such a range as to produce the most desirable combination of convention levels of the olefin fed and high selectivity for the product. The recovery of the produced epoxide product can be carried out easily employing techniques well known to those skilled in the art. For example, where the reaction is carried out in the continuous mode, the initial material that did not react is initially separated from the reaction products; and the desired product is isolated after the mixture of the resulting product by distillation, crystallization, extraction, or the like. Since the selectivity for the desired epoxide product is quite high, there are only small amounts of unwanted reaction products from which the desired product must be isolated.

Prior to the use of oxidizing olefins which do not have alane hydrogens, the silver catalysts (either before or after further treatment with a promoter) are optionally calcined in an oxygen-containing atmosphere (air or helium supplemented with oxygen) at a temperature of 350 ° C for about 4 hours. After calcination the silver catalysts are typically subjected to an activation treatment at a temperature in the range of 300 to 350 ° C in an atmosphere that initially contains 2 to 5 percent of the hydrogen in an inert carrier such as helium or nitrogen. The hydrogen content of the activation atmosphere is gradually increased to a final hydrogen concentration of 20 to 25 percent, at a controlled rate, so that the activation temperature does not exceed 350 ° C. After the temperature is maintained for about one hour at a concentration of hydrogen which is in the range of 20 to 25%, the catalyst is ready for use. More detailed descriptions of the silver catalysts and their use in oxidizing olefins that do not have allylic hydrogens are found in U.S. Patent Nos. 4,897,498 and 5,081,096. The invention will be illustrated by the following illustrative modalities.

Illustrative Modalities Preparing the operator The basic material of the following carriers was formulated as set forth in U.S. Patent No. 5,380,697. The combustible material in carriers A, C, and E was 30 parts of a particulate polypropylene, having a maximum particle size of 150 microns and an average particle size of about 90 microns.

In carriers B, D, and F, the combustible material used was 42 parts of crushed walnut shells, with an average particle size of 177 microns.

Carrier A The carrier was made using the formulations described below, and the procedure used was as follows: Ceramic components (270 parts of alpha alumina, 101 parts of gibbsite, 22 parts of boehmite) are mixed with the combustible material. To this mixture are added: 5 parts of an inorganic binder material; 15 parts of an organic binder; 7 parts of starch and 0. parts of boric acid, and the components are mixed for about 45 seconds. After this mixing operation, the following components are added: water; 0.1 parts of a surfactant ("Triton" available under this trade name in Unicr. Carbide Corporation); the titania-containing component (0.6 parts of an anatase with a surface area of about 16 m / g); and parts of a sowing component based on fine alpha alumina. The amount of water added was the amount necessary for the mixture to be exuded. Generally this is about 120 to 125 parts by weight. The mixture is stirred for an additional 4.5 minutes and then Vaseline is added to form a mixture that can be extruded (Vaseline is a trademark). The mixture is then stirred for an additional 3.5 minutes before being extracted and shaped into hollow cylinders and dried to less than 2 percent unmatched water. These cylinders were then heated in a kiln tunnel with a maximum temperature of approximately 1, 420-1,225 ° C for about 4 hours. The carrier is described in terms of its physical properties, in Table 1. Carrier B: Carrier B was prepared in a manner similar to Carrier A except that traditional fuel material, ie walnut shells, were added to the formulation of the carrier. The carrier is described in terms of its physical properties in Table 1.

Carrier C: Carrier C was prepared in a similar manner except that a water-soluble titania precursor (4.4 parts of lactic acid chelate, titania containing approximately 4.6 parts of titania) was used in the carrier, instead of powdered titania, and the carrier burned at a temperature of 1,385-1,390 ° C. The carrier is described in terms of its physical properties in Table 1. Carrier D: Carrier D was prepared in a manner similar to Carrier C except that a traditional combustible material, ie walnut shells, was used. The carrier is described in terms of their physical properties in Table 1. Carrier E: Carrier E was prepared in a manner similar to carrier A except that the carrier did not contain titania, and the carrier was burned at a temperature of 1.470 ° -1.480 °. The carrier is described in terms of its physical properties in Table 1. Carrier F: Carrier F was prepared in a manner similar to Carrier E except that a traditional combustible material, ie walnut shells, was used. The carrier is described in terms of its physical properties in Table 1.

TABLE 1 CARRIERS PROPERTIES or 1"Surface area 2 is the BET surface area measured using nitrogen or krypton as absorbate 2" Density packed "is the packed measurements seated as measured by ASTM-D 4699-87, modified by the use of a cylinder with an inner diameter of 9.4 cm (3 * s of an inch, and a length of 46 cm 18 inches, or equivalent) 3"Water absorption" is a measure of the increase of 1 weight of a carrier after being submerged in water and after being weighed 4"Crushing resistance" is measured in a Compton Tensile Tester, Model 50-OP tension analyzer 5"Crushing" is the crushing strength and is the amount of carrier weight loss, measured as an ASTM percentage. -D-4058-92 6"Leachable" were measured using the nitric acid solution technique.

Preparation of Catalyst The following illustrative embodiment describes preparation techniques, for manufacturing the catalysts of the present invention (catalysts A, C and E) and the comparative catalysts (Comparative Catalysts B, D and F) and the technique for measuring the properties of those catalysts.

Part A: Preparation of concentrated silver oxalate / ethylendiamma solution, for use in a catalyst preparation. 1) Dissolve 415 (g) of reactive grade hydrogen in 2,340 (mi) of deionized water. Adjust the temperature to 50 ° C. 2) Dissolve 1,699 g of silver nitrate (high purity) in 2,100 milliliters of deionized agj. Adjust the temperature to 50 ° C 3) Slowly add solution and sodium hydroxide to the silver nitrate solution, with stirring, while keeping the temperature at 50 ° C. Stir for 15 minutes after completion the addition, then lower the temperature to 40 ° C. 4) Insert clean filter rods and remove water, as much as possible, from the precipitate created in the vessel (3) to remove the sodium and nitrate ions Measure the conductivity of the water remove and add again as much fresh deionized water, as has been removed by the filter rods, stir for 15 minutes at 40 ° C. Repeat this process until the conductivity of the water removed is less than 90 μmho / cm, then add again 1,500 5) Add 630 g of high purity oxalic acid dihydrate in increments of approximately 100 g Keep the temperature at 40 ° C and shake to mix thoroughly Add the last portion of the di. oxalic acid hydrate, slowly, and inspect the pH to ensure that the pH does not drop below 7.8 6) Remove as much water from the mixture as possible, using clean filter rods, to form a watery paste containing silver, highly concentrated Cool the aqueous paste with silver oxalate until 30 ° C. 7) Add 699 g of endothelium (8% deionized water) to 92 percent by weight (92% p). Do not allow the temperature to exceed 30 ° C during the addition. The above process produces a solution containing approximately 27 to 33% by weight of silver that provides the "concentrated solution" used in the preparation of the catalysts A, C, and E, and the subsequent comparative catalysts B, D and F.

Part B: Preparation of impregnation solutions, used for catalyst A: To 153 grams of concentrated silver solution, with a relative density of 1526, 0.33 grams of NH4F in 2 cups of water are added. 1017 g of LiOH monohydrate are suspended in 5 g of water, and the suspension is then added to the previous silver solution. The solution is stirred until it is dissolved in LiOH. CaOH (50% solution in water) is added in an amount of 0.1121 grams, to 50 grams of the above silver solution and the resulting mixture is used for the impregnation of the carrier.

For the comparative catalyst B: To 150 grams of concentrated silver solution, with a relative density of 1526, 0.032 grams of NH4F in 2 cups of water are added. 1007 grams of LiOH monohydrate are suspended in 7 grams of water, and the suspension is then added to the previous silver solution. The solution is stirred until the LiOH 'dissolves. CsOH (50% solution in water) is added in an amount of 0.1132 grams to 50 grams of the above silver solution and the resulting mixture is used for the impregnation of the carrier.

For the catalyst C 181 grams of concentrated silver solution were diluted, with a relative density of 1,565, 1.3 grams of water. To the silver solution were added 0.035 grams of silver NH4F in 2 cups of water. 0.5497 grams of monohydrated LiOH were dissolved in 20 grams of water and added to the previous silver solution. CsOH (50% water solution) was added in an amount of 0.1200 grams, to 60 grams of the above silver solution, and the resulting mixture was used for the impregnation of the carrier.

For the comparative catalyst D: They were diluted, with 6.5 grams of water, 181 grams of concentrated silver solution, with a relative density of 1.565 grams. 0.0034 grams of NH4F in 2 cups of water were added to the silver solution. 0.5316 grams of LiOH monohydrate was dissolved in 20 grams of water and added to the previous silver solution. CsOH (50% solution in water) was added in an amount of 0.1555 g at 0 grams of the above silver solution, and the resulting mixture was used for impregnation of the carrier.

For the catalyst E 183 grams of concentrated silver solution, with a relative density of 1565, were diluted with 19.6 grams of water and 12.6 grams of monoethanolamine. 0.033 grams of NH4F were dissolved in 2 ml of water. CsOH (50% solution in water) was added in an amount of 0.1117 grams, to 60 grams of the silver solution diluted above and the resulting mixture was used for the impregnation of the carrier.

For the comparative catalyst F: 183 grams of concentrated silver solution, with a relative density of 1555, were diluted with 12.5 grams of water and 13.2 grams of monoethanolamine. 0.034 gram of NH4F was dissolved in 2 cc of water and added to the silver solution. CsOH (50% solution in water) was added in an amount of 0.1137 grams, to 60 grams of the silver solution diluted above, the resulting mixture was used for the impregnation of the carrier.

Part C Impregnation of the catalyst and cure of the catalyst A: Approximately 30 grams of carrier A (described above in Table 1) is placed under 25 mm vacuum, for 3 minutes at room temperature. Then approximately 50 to 60 grams of the impregnation solution are introduced, with added material (as described in part B above under the text "for catalyst A") to immerse the carrier, and the vacuum is maintained at 25 mm. , for about 3 additional minutes. At the end of this time the vacuum is suspended or released, and the excess impregnation solution is removed from the carrier by centrifugation for 2 minutes at 500 rpm. If monoe anolamin occurs in the impregnation solution, then the impregnated carrier is cured by stirring continuously in an air stream of 8.5 m 3 / h (300 ft3 / h) flowing through a cross-sectional area of approximately 2. 19.35 - 32.25 cm (3-5 square inches) at a temperature range of 240 to 270 ° C for a time of 3-6 minutes. If a significant amount of monoethanolamine is present in the impregnation solution, then the impregnated carrier is cured by continuous agitation in an air stream of 8.5 m3 / h (300 ft / h) at a range of 250 ° C to 270 ° C for a time of 4 to 8 minutes. The cured catalyst is then ready for its anal i s i s. The properties of catalyst A are shown in table 2 below.

Comparative catalyst B: Comparative catalyst B was prepared in the same manner as catalyst A, except that the catalyst carrier B was used in place of catalyst carrier A and the impregnation solution used was that described in part B above under the text "for the comparative catalyst B ". The properties of comparative catalyst B are shown in Table 2 below.

Catalyst C Catalyst C was prepared in the same manner as catalyst A, except that a catalyst carrier C was used in place of the catalyst carrier A and the impregnation solution used was that described in part B above under the text "for the catalyst B ". The properties of catalyst C are shown in Table 2 below.

Comparative catalyst D: Comparative Catalyst D was prepared in the same manner as catalyst A, except that the catalyst carrier D was used in place of the catalyst carrier A and the impregnation solution used was that described in part D above under the text "for the comparative catalyst D ". The properties of comparative catalyst D "are presented in Table 2 below.

Catal i zador E Catalyst E was prepared in the same manner as catalyst A, except that the catalyst carrier E was used in place of catalyst carrier A and the impregnation solution used was that described in part B above under the text "for the catalyst E ".

The properties of the catalyst E are those shown in Table 2 below.

Comparative catalyst F Comparative catalyst F was prepared in the same manner as catalyst A, except that the catalyst carrier F was used in place of a catalyst carrier A and the impregnation solution used was that described in part B above under the text " Pa to the catalyst F ". The properties of comparative catalyst F are shown in Table 2 below.

TABLE 2 PROPERTIES YOU THE CATALYSTS As can be seen in Table 2, the catalysts according to the invention (catalysts A, C, and E) have improved properties with respect to crushing strength and wear resistance when compared to Comparative Catalysts that are not in accordance with the invention (comparative catalysts B, D, and F.) The actual silver content of the catalyst can be determined by any number of standard published procedures. The actual level of cesium can be determined by using a concentrated solution of cesium hydroxide, which has been labeled with a radioactive isotope of cesium, in a catalyst preparation. The catalyst can then be determined, by measuring the radioactivity of the catalyst. Alternatively, the cesium content of the catalyst can be determined by leaching the catalyst with deionized and boiling water. In this process of extraction, the cesium, like other metals - alkali, is measured by the extraction of! catalyst, boiling 10 g of the whole or total catalyst in 20 ml of water, for minutes, repeating the above two more times, combining the amount of alkali metal present, by comparison with standard solutions of alkali metals present, using a spectroscope (using a Variety Techtron, Model 1200 or equivalent).

Part D: Conditions / Procedure for analyzing the catalyst in a standard microreactor.

A: For catalysts A and C and pa the comparative catalysts B and D: They are loaded with 1 to 3 g of crushed catalyst (20-30 mesh, ie 0.841-0.595 mm i in a U-shaped stainless steel tube with a diameter of 6 mm.) The U-shaped tube is immersed in a bath of molten metal (thermal medium) and the ends are connected to a gas flow system.The weight of the catalyst used / the gas flow inlet are adjusted to achieve a space velocity value per hour, of gas, of 6,800 The gas outlet pressure is d <% 1,550 kPa.

The gas mixture passing through the catalyst bed (in a 1-step operation) throughout the test (including start-up) consists of 25% ethylene, 7% oxygen, 5% carbon dioxide, 1.25 to ppmv of ethyl chloride and the nitrogen / argon moiety. The start or start procedure involves raising the temperature from 180 ° C to 230 ° C in the following way: 1 hour at 180 ° C, 1 hour at 190 ° C, 1 hour at 200 ° C, 1 hour at 210 ° C , 1 hour at 220 ° C, 2 hours at 220 ° C, 2 hours at 225 ° C, 2 hours up to 230 ° C, and then the temperature was given 1.5% ethylene oxide at the reactor outlet. The selectivity of the catalyst (Si.5) and the activity of the catalyst (T1.5) were measured at those conditions. To allow a meaningful comparison of the performance or performance of the catalysts analyzed at different times, the catalysts A and C, and the comparative catalysts B and D were analyzed simultaneously with a standard reference catalyst that had a Si.5 value = 81.7% and Ti.5 = 235 ° C. The catalysts A and C and the catalysts B and D above were analyzed using the above procedure, and the results are presented in Table 3 below.

TABLE 3 CATALYST PERFORMANCE B. For the catalyst E and comparative catalysts F: 3 to 5 grams of the crushed catalyst (14-20 mesh, ie 1,410-0,841 mm) are loaded in a U-shaped stainless steel tube with a diameter of 6 mm. The U-shaped tube is immersed in a bath of molten metal (thermal medium) and the ends are connected to a gas flow system. The catalyst weight used and the inlet gas flow are adjusted to obtain a space velocity per hour, of gas, of 3,300. The outlet gas pressure is 1, 550 kPa. The gas mixture passing through the catalyst bed (in a one-step operation) throughout the test (including start-up) consists of 30% ethylene, 8.5% oxygen, 5% carbon dioxide, 1.5 to 5 ppmv of ethyl chlorohydrate, and the rest of nitrogen / argon. The catalysts were started to work in a manner similar to the catalysts A and C, and comparative catalysts B and D. Due to slight differences in the composition of feed gas, in gas flows, and in the calibration of the instruments The analytical agents used to determine the gas and feed composition and product composition, the selectivity and activity measured, of a given catalyst may vary slightly from one assay to the next. To allow a meaningful comparison of the performance or performance of the analyzed catalysts at different times, all the catalysts described in this illustrative embodiment were analyzed simultaneously with a standard reference catalyst having a value of S or = 81.0% and T40 = 230 ° C. .

TABLE 4 It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, the content of the following is claimed as property:

Claims (14)

1. A catalyst for the epoxidation, or conversion to epoxide, of olefins which do not have allylic hydrogen, in particular ethylene, with molecular oxygen, the catalyst is characterized in that it comprises a catalytically effective amount of silver and an alkali metal promoting amount, optionally a rhenium promoting amount and optionally a promoter amount of a rhenium copromotor, deposited on a carrier or support which is prepared by a process comprising mixing ceramic components in particle form, with an amount of 0.5 by weight to 50 parts by weight, based on 100 parts by weight of the ceramic components, of polypropylene, in the form of a powder having an average particle size of less than 400 microns and an ash content of less than 0.1% by weight, and then cooking bake at a temperature sufficient to burn the synthetic organic polymer, sinter the component in the form of particles and form a carrier or support.

2. The catalyst according to claim 1, characterized in that in the carrier, the polypropylene is present in an amount that is from 1 to 40% of the weight of the ceramic components.

3. The catalyst according to claim 1, characterized in that in the carrier, the ceramic components comprise at least 90% by weight of alpha alumina.

4. The catalyst according to claim 1, characterized in that in the carrier, the polypropylene has an ash content of less than 0.05% by weight.

5. The catalyst according to claim 1, characterized in that in the carrier, a bonding or ceramic bonding material is added to the extrudable mixture, in an amount that is 0.01 to 5% of the weight of the ceramic components in the mixture .

6. The catalyst according to claim 1, characterized in that the carrier comprises from 0.01 to 5% by weight, based on the total weight of the cooked carrier, of a compound selected from the group consisting of an alkaline earth metal oxide, silicon dioxide , zirconia dioxide and mixtures thereof.

7. The catalyst according to claim 1, characterized in that the carrier further comprises 0.05% by weight to 5% by weight, based on the weight of the cooked carrier, titania or titanium oxide.

8. The catalyst according to claim 1, characterized in that the silver varies from 1 weight percent to 40 weight percent of the total catalyst, and the alkali metal varies from 10 parts per million to 3,000 parts per million, expressed as the metal , by weight of the total catalyst.

9. The catalyst according to claim 8, characterized in that the alkali metal promoter is selected from the group consisting of potassium, rubidium, cesium, lithium and mixture thereof.

10. The catalyst according to claim 9, characterized in that the promoter is cesium.

11. The catalyst according to claim 1, characterized in that the alkali metal promoter comprises cesium plus at least one additional alkali metal.

12. The catalyst according to claim 1, wherein the rhenium copromotor is selected from the group consisting of sulfur, molybdenum, tungsten, chromium, phosphorus, boron and mixtures thereof.

13. A process for the production of ethylene oxide, characterized in that the ethylene is contacted, in the vapor phase, with an oxygen-containing gas, at the conditions for the formation of the ethylene oxide at a temperature varying from 180 °. C up to 330 ° C, in the presence of a catalyst according to any of claims 1 to 14

14. A process for the epoxidation or epoxide conversion of olefins which do not have alane hydrogens, characterized in that an olefin having no allylic hydrogen is contacted, in the vapor phase, with a gas containing oxygen, under the conditions of formation of the epoxide at a temperature in the range of from 75 ° C to 325 ° C in the presence of an organic halide and a catalyst according to any of claims 1 to 12.