Method of obtaining alkylene oxide using gas-phase promoter system

FIELD: chemistry, medicine.

SUBSTANCE: additive to reaction of epoxidation represents two-component gas-phase promoter system, which contains chlorine-containing component (for instance, ethyl chloride, methyl chloride, vinyl chloride and ethylene dichloride) and nitrogen-containing component from group of nitrogen monoxide and other compounds able to form in reaction conditions at least one gaseous, increasing efficiency, member of pair of oxidation-reduction semi-reaction, including NO, NO₂, N₂O₃ or N₂O₄. Quantity of each component of said gaseous promoter is taken in such way as to support ratio N* to Z* within the interval from 0.4 to 1, where N* represents equivalent of nitrogen monoxide, in ppmv, ranging from 1 to 20 ppmv, and Z*=(ethyl chloride equivalent (ppmv))x100%/(ethane equivalent (mol %))x100, ranging from 5 to 40 ppmv. Said equivalents are determined depending on concentrations of nitrogen-containing component, chlorine-containing component and ethane or other hydrocarbon at reactor inlet in accordance with stated in i.1 of the formula.

EFFECT: improved is method of obtaining ethylene oxide by means of ethylene epoxidation using catalyst, which contains silver and one efficiency-increasing salt of member of oxidation-reduction semi-reaction pair.

7 cl, 7 tbl, 4 ex

Description

The indication of the cross-reference

This application takes advantage of the provisional application U.S. No. 60/507011, filed September 29, 2003.

The technical field

This invention relates to a gas promoter systems designed to improve the performance of catalysts used in epoxydecane of ethylene to ethylene oxide. More specifically, this invention relates to a gas promoter system, which uses the synergy between the two gaseous modifiers: gaseous nitrogen-containing components capable of generating at least one reinforcing the effectiveness of the participant pairs in redox polyreactive, and gaseous chlorine-containing components.

Background of invention

Getting accelerated, such as ethylene oxide, oxygen or oxygen-containing gases with ethylene in the presence of silver-containing catalyst at elevated temperature, an old well known in the art by the way. For example, in U.S. patent No. 2040782, dated may 12, 1936, describes the obtaining of ethylene oxide by the interaction of oxygen with ethylene in the presence of silver catalysts containing promoters belonging to the class of metal-containing solid pramatarov reissued U.S. patent 20370, dated may 18, 1937, Leforte shows that the formation of olefination you can call, prompting the olefins to a direct connection with molecular oxygen in the presence of a silver catalyst. (For a detailed discussion on ethylene oxide, including a detailed description of commonly used process steps of receiving, found in Kirk-Othmer'sEncyclopedia of Chemical Technology, 4^thEd. (1994), Volume 9, pages 915-959.)

The catalyst is the most important element in the direct oxidation of ethylene to obtain ethylene oxide. There are several well-known mandatory components of such catalyst: silver suitable base/media (e.g., alpha-alumina), and promoters, which may play a role in the improved performance of the catalyst. Because of the importance of the catalyst in obtaining ethylene oxide substantial efforts have been made to improve the performance of such catalysts.

The use of suitable promoters is an effective and proven way to increase the efficiency of the catalyst in obtaining accelerated, for example, ethylene oxide, and such use is well known to specialists in this field of technology. There are at least two types of promoters - solid promoters and gaseous promoters. Solid promoter include in the catalyst prior to its use or the AK part of the media (i.e. basis), or as part of a silver component deposited on it. When a firm promoter added during the preparation of the catalyst, it can be added to the media prior to deposition on him a silver component, add simultaneously with a silver component, or add after the deposition of the silver component on the carrier. Examples of well-known solid promoters for catalysts used to obtain ethylene oxide include compounds of potassium, rubidium, cesium, rhenium, sulfur, manganese, molybdenum and tungsten. During use of the catalyst in the reaction of receipt of ethylene oxide particular form of the promoter in the catalyst may be unknown.

In contrast, gaseous promoters are compounds in the gas phase and/or mixtures thereof, which is introduced into the reactor to obtain accelerated (e.g., ethylene oxide) with the reactants in the vapor phase, such as ethylene and oxygen. Such promoters also increase the efficiency of this catalyst, working in conjunction or in addition to solid promoters.

It is well known that catalysts using some solid promoters, in particular where the use of at least one efficiency-enhancing salt of a member couples the redox of polyreactive, the introduction of a gaseous component capable of obrazovawe the ü one of the participants of the pair of redox of polyreactive, beneficial for maintaining the selectivity and activity (see U.S. patent 5387751, 4837194, 4831162, 4994587, 4994589, 4994588, 5504053, 5187140 and 6511938 B1).

Used in this description, the term "salt" does not imply that the cationic and anionic components of salt necessarily associated or related to each other in the solid catalyst, but rather, it implies that under the reaction conditions the catalyst in some form are present in both of the component.

In the catalysts used in the method according to the present invention, the gaseous component capable of forming in the conditions of the reaction member couples the redox of polyreactive represents a nitrogen-containing gas, such as, for example, of nitrogen monoxide, nitrogen dioxide and/or chetyrehokisi dinitrogen, hydrazine, hydroxylamine or ammonia, nitroparaffin (e.g. nitromethane), reduction of the connection (e.g., nitrobenzene), N-nitrosoaniline and/or a nitrile (e.g. acetonitrile). The amount of gaseous nitrogen-containing promoter used in these catalysts, is a quantity sufficient to improve the working characteristics, such as the activity of the catalyst, and in particular, the efficiency of the catalyst. The amount of gaseous nitrogen-containing promoter, generally described in the above patents as defined specific use what has been created efficiency-enhancing salt of a member couples the redox of polyreactive and its concentration, the particular the alkene undergoing oxidation, and other factors, including the amount of carbon dioxide in the incoming reaction gases. For example, in U.S. patent 5504053 revealed that when gaseous nitrogen-containing promoter is a NO (nitric monoxide), the proper concentration in the gas stream is from 0.1 to 100 ppm by volume. Preferably, when CO₂(carbon dioxide) is present in an amount up to 3 vol.%, NO is present in an amount of 0.1-60 OBC/million (ppm), preferably 1-40 OBC/million in U.S. patent 5387751 discloses a continuous method of producing ethylene oxide, comprising contacting ethylene, oxygen, silver-containing catalyst and from 1 to 50 ppm, by weight, of vinyl chloride as a modifier of the reaction, the nitric oxide at a concentration of 0.5-50 ppm equivalent NO₂the process gas by volume, and the specified nitric oxide in terms of the way it forms in the catalyst of nitrate - or nitrite-ions.

From the literature, devoted to the catalysts, it is known that the concentration of gaseous chlorine-containing promoter (also known as a modifier or inhibitor), which is required for optimal performance depends on the amount of hydrocarbons present in the gas phase, and other factors (J.M. Berty, Applied Industrial Catalysis, Vol.1, Chapter 8, p. 224-227, 1983). Describes the specific the RCM reaction, in which the hydrocarbon remove chlorides from the catalyst surface, and it is known that while Ethan removes chlorides very effectively, ethylene is also able to remove the chlorides, but found that it is much less effective. In WO 03/044002 A1 and WO 03/044003 A1 disclosed a method of optimizing gas promoters for highly selective catalysts in the reaction phases with different compositions of load and temperature, respectively. It is assumed that the optimum content of the modifier depends on the effective molar quantity of hydrocarbons present in the load, and the effective molar quantity of active substances response modifier.

Usually use a number of terms to describe some of the parameters of the catalytic system for epoxidation of alkenes. For example, "conversion" is defined as the molar percentage of alkene loaded in the reactor, which undergoes reaction. Of the total number of alkene, which process the reaction is converted into another chemical substance, the molar percentage, which is converted into the corresponding accelerated, known as "efficiency" (which is synonymous with "selectivity") of the process. Work efficiency, in percent, at the conversion rate, in percent (divided by 100 percent for translation %²in %) represents procent is th "exit", i.e. the molar percentage loaded alkene, which turned into the corresponding epoxide.

"Activity" of the catalyst can be quantified in several ways, and one of them is the molar percentage of accelerated contained in the stream exiting the reactor, relative to its content in the incoming stream (molar percentage of accelerated in the incoming stream is typically, but not necessarily, zero percent), while the temperature in the reactor is maintained essentially constant, and the other is the temperature required to maintain a given rate of formation of alkalinized. In other words, in many cases, the activity is measured over time in the values of the molar percent of accelerated obtained at a certain constant temperature. On the other hand, the activity can be measured as a function of the temperature required to maintain get a specific permanent molar percent of alkalinized. "Useful life" of a catalytic system represents the period of time during which the reagents can pass through the reaction system, for which the results are assessed by a specialist as appropriate in light of all factors considered.

Used in this description, the term "decontamination" relates the I to the irreversible reduction of activity and/or efficiency, i.e. drop in activity and/or efficiency that cannot be restored. As noted above, the product of accelerated you can intensify, increasing the temperature, but the need to work at a higher temperature to maintain a certain speed of the receiving characteristic of irreversible loss of activity. "Sustainability" of the catalyst is inversely proportional to the rate of deactivation, i.e. the rate of decrease in the efficiency and/or activity. As a rule, the less the rate of fall of efficiency and/or activity.

In order that the catalyst was considered to be satisfactory, it must have acceptable activity and efficiency, and the catalyst must also be sufficiently stable so that it had a sufficiently long period of normal operation. When efficiency and/or activity of the catalyst drops to unacceptably low levels, typically, the reactor must be stopped and partially disassemble to remove the catalyst. This leads to the cost of time, performance, and materials, for example silver catalytic material and oxindolimine media. In addition, the catalyst must be replaced, and silver are to be disposed of or, when possible, to regenerate. Even when the catalyst is able to regenerate in situ, as a rule, the process of neobhodimosti for some time. In the best case, the replacement or regeneration of the catalyst requires additional losses in production time for processing of the catalyst, and at worst you will need to replace the catalyst and the associated costs. It is therefore desirable to find a means of extending the useful life of the catalyst.

The invention

One aspect of the present invention relates to a method for production of ethylene oxide by the epoxidation of ethylene in a reactor having at least one inlet for the introduction of raw materials and additives and at least one outlet for the discharge of ethylene oxide, including

A) interaction of a raw material containing ethylene, oxygen and, optionally, ethane, in the presence of a catalyst, with the specified catalyst contains a catalytically effective amount of silver on an inert refractory solid carrier and at least one efficiency-enhancing salt of a member couples the redox of polyreactive;

C) adding to the said loading two-component gas-phase promoter containing at least one chlorine-containing component selected from the group consisting of ethylchloride, methyl chloride, vinyl chloride and ethylene dichloride; and at least one nitrogen-containing component selected from the group consisting of nitric monoxide and other compounds capable of at the conditions of the reaction to form, at least one gaseous efficiency-enhancing member of a pair of redox of polyreactive, including NO, NO₂N₂O₃or N₂O₄;

(C) specifying the amount of each component of the specified gas-phase promoter to maintain the relationship N* Z*, is equal to 1 or smaller, where

N* represents the equivalent of nitrogen monoxide, in units OBC/million, with a numerical value from 1 to 20 OBC/million, and

having a numerical value of from 5 to 40 OBC/million; and

D) regulating the temperature of the specified reactor from 200°C to 300°C and pressure at the inlet of the specified reactor from 1000 to 2500 kPa (absolute) and the concentration of carbon dioxide in the specified entry from 0 to 2 mol.%.

Another aspect of the present invention relates to a catalyst containing from 5 to 50 wt.% silver relative to the weight of the catalyst.

Another aspect of the present invention relates to refractory solid base containing alpha-alumina having a morphology comprising fused plates.

Although the present invention should not be understood as limited to any particular theory, it is assumed that the gaseous nitrogen-containing promoter, when it is introduced into the reactor with gaseous chlorine-containing promoter, the solid catalyst and other materials, the same is as ethylene and oxygen, improves overall performance of the catalyst, influencing the amount of nitrogen-containing particles on the catalyst surface, which directly affects the efficiency of the catalyst. Chlorine-containing substances also increase efficiency. Both substances have the optimal concentration determined by the balance between promoting effect on the efficiency and/or activity and/or stability, blocking seats for the reaction and amplification or inhibition of secondary reactions between different substances present in the system. The new aspect of this invention is the discovery that the presence of such secondary reactions leads to the correlation of the optimum gaseous nitrogen-containing chlorine-containing promoter and promoter for catalysts containing efficiency-enhancing salt of a member couples the redox of polyreactive that was previously not known.

The key distinguishing feature of the present invention is entering a particularly advantageous quantities of gaseous nitrogen-containing promoter and gaseous chlorine-containing promoter to obtain synergistic effects in improving the performance of a catalyst to obtain ethylene oxide by the method of vapor-phase epoxidation of ethylene.

Detailed description of the invention

Preferably policemilitary using a solid catalyst, containing silver, to carry out gas-phase method in a reactor in which a gaseous raw material or so-called incoming load passes through the layer of solid-phase catalyst containing silver and added the promoters. In such a way that, as a rule, is carried out continuously, gaseous promoters, sometimes called modifiers, inhibitors or enhancers, add in the incoming gases are used as raw materials for the production of ethylene oxide, and other gases present in the system. Raw material includes ethylene and oxygen. Ethane and other hydrocarbons, including sometimes the methane can be added to regulate the gaseous chlorine-containing promoter, as well as to changes of thermal and chemical properties of the gas mixture and to facilitate control of the reaction. Carbon dioxide and water are produced as by-products of the reaction, as a rule, remain from the recycling of the reaction gases or impurities. Can also contain nitrogen and other inert gases such as argon. Nitrogen, methane or other gases, creating a balance of incoming load, sometimes referred to as the ballast gas.

The pressure in the reaction varies depending on the reactor design, but typically is in the range of 1000 kPa to 2500 kPa, absolute. Preferably the pressure in the reactor ranges from 1800 kPa to 2500 kPa (absolute is Noah).

The temperature in the reactor is an important parameter with a working range 200°C-300°C. In the present invention the preferred range of temperature for the reactor ranges from 210°C. to 280°C.

The ethylene concentration in the raw material can vary in a wide interval. Typically, the ethylene concentration will be from 18 to 35 mol.%, and preferably from 20 to 32 mol.% of the total load. The specified concentration can be adjusted with the time of operation of the catalyst for a variety of reasons, including performance characteristics of the catalyst and ease of operation.

The oxygen concentration in the raw material is not the subject of this invention and can vary in a wide interval. In practice, the main consideration is the Flammability of the reaction gases, which may limit the oxygen concentration. Typically, the oxygen concentration will vary from 1 to 15 mol.%, typical from 2 to 12 mol.%, of the total load.

The concentration of carbon dioxide in the raw materials has a strong detrimental effect on the efficiency, activity and/or stability of the catalysts used in the present invention. Carbon dioxide is formed as a side product of the reaction, and it can also be administered with other reactive gas as impurity. In the present invention, the concentration of carbon dioxide at the inlet is limited to the amount the Oh from 0 to 2 mol.% in gases, coming from the boot. Water is also a byproduct of the reaction and may be present in the incoming gases in concentrations from 0 to 3 mol.%.

In addition to ethylene, ethane or other hydrocarbons can act as agents dechlorination catalyst surface and can also be added to the incoming gases to facilitate regulating the amount of chlorine-containing promoter. Some of these hydrocarbons can also act as impurities in the ethylene loading or may be present for other reasons. Typically the preferred concentration of ethane, when present, ranges from 0 to 2 mol.%.

Methane, or nitrogen, or other gas can be used to obtain the volume of the gas load, which is not raw materials, additives, by-products or impurities. In such situations, the used inert gas, which is a ballast gas is from 50 to 80 mol.% from the incoming gases, except start or stop, when the concentration may vary within wide limits. As ballast gas can also be used other hydrocarbons.

In the method of producing ethylene oxide in the present invention the inert gases mentioned in this description, mixed with two gas promoters represents a nitrogen-containing promoter and chlorine-containing promoter. On the of Adak, in which the incoming gases and promoters mixed together, is not essential in the present invention, and they can be mixed simultaneously or sequentially. The order of mixing of the gaseous components of the method can be chosen for reasons of convenience or security. For example, oxygen is usually added after the ballast gas for safety reasons. Decisive is only that both gaseous promoter present in the incoming load introduced into the reactor containing the solid catalyst. After the introduction coming from the boot of gases in the solid catalyst in a reactor operating at a certain pressure and temperature, in the implementation of the present invention found that it is desirable to adjust the effective concentration of the two gaseous promoters in a certain interval ratios in order to obtain the highest performance of the catalyst upon receipt of ethylene oxide.

In the prior art it is known that catalysts having high activity, require the use of a solid catalyst, in addition to the gaseous chlorine-containing promoter, gaseous nitrogen-containing promoter, which subsequently provides the pair of redox of polyreactive, and at least one enhancing salt of a participant who and couples the redox of polyreactive.

Gaseous nitrogen-containing promoter is added to the incoming load to provide a pair of redox of polyreactive, you can choose from a number of nitrogen monoxide, nitrogen dioxide, dinitrogen tetroxide, hydrazine, hydroxylamine, ammonia, nitroparaffins (e.g. nitromethane), reduction of compounds (e.g., nitrobenzene), N-nitro compounds, NITRILES (e.g. acetonitrile) and/or mixtures thereof. The effectiveness of each of these compounds as the promoter in the correct formation reaction of ethylene oxide depends on its ability to provide a catalyst for nitrogen - and oxygen-containing particles and, in particular, on the ability of the compound to generate in the reactor NO,

NO₂N₂O₃and/or N₂O₄. Under the reaction conditions may occur vzaimoprevrascheny nitrogen - and oxygen-containing particles, and can prisustvovati several substances from among NO, NO₂N₂O₃and N₂O₄.

Although the present invention should not be understood as limited to any particular theory, it is assumed that optimum performance of the catalyst depend on the concentration of gaseous nitrogen-containing promoter, and the concentration of gaseous chlorine-containing promoter because of the existence of certain chemical reactions between azo is containing particles, chlorine and/or chlorine-containing particles and/or solid components of the promoter of the catalyst under the reaction conditions. Although most of these reactions occur on the catalyst surface, some may also occur in the catalyst or in the gas phase.

An effective amount (the amount that actually participates in the reaction in the catalyst during the process of obtaining ethylene oxide) gaseous promoters is not necessary the same as the actual number of promoter entered in the incoming load. The effective amount of nitrogen-containing promoter depends on the pressure, the amount of carbon dioxide, operating temperature and properties of the catalyst, such as the lifetime of the catalyst. The effective amount of chlorine-containing promoter depends on the amount of hydrocarbon that is capable of removing chlorine from the catalyst surface, and the operating temperature. In addition, various compounds that can be used as a gaseous promoter, have different levels of effectiveness. The effectiveness of a particular gaseous nitrogen-containing promoter is determined by its ability to generate the active catalyst nitrogen - and oxygen-containing members of the pair of redox of polyreactive. The effectiveness of a particular gaseous chlarotera is his promoter depends on its ability to precipitate in certain catalyst particles chlorine, for example, atomic chlorine or chlorine ions.

Used in this description, the term "catalyst" includes the surface of the catalyst, the inner part of the catalyst (i.e. below the surface) and/or the gas phase over the catalyst.

The efficiency of gaseous promoter used in the method according to this invention, it is necessary to determine experimentally, taking into account the discussion above. In the case of nitrogen-containing promoter as a standard connection using nitric monoxide (NO), which determine the relative effectiveness of other nitrogen-containing compounds. The pressure in the reactor also has an impact on the efficiency of nitrogen-containing promoters and, therefore, should be taken into account. In the present invention N* is a measure of the overall efficiency of nitrogen-containing promoters and is defined as

N* = equivalent of nitrogen monoxide (ABC/million).

If NO is the only gaseous nitrogen-containing promoter that is present at the input, N* represents the NO concentration at the entrance to OBC/million multiplied by the inlet pressure in kilopascals, (absolute) divided by 2300 kPa. When using other assadabadi promoter, alone or in combination with NO equivalent of nitrogen monoxide is a product of the concentration of NO in ABC/million plus concentration drugog isostearamide promoter (adjusted for its effectiveness as a promoter compared to NO) and inlet pressure in kilopascals, (absolute) divided by 2300 kPa. The relative effectiveness of no-NO promoter can be measured experimentally, replacing NO other promoter and determining the concentration needed to obtain the same level of performance of the catalyst, which ensures NO. For example (for clarification) if the required concentration of NH₃at the entrance of the reactor for the implementation of equivalent efficiency in the performance of the catalyst, provide 1 OBC/million NO equivalent to 1.5 OBC/million, then the equivalent monoxide nitrogen for 1 OBC/mn NH₃should be 0,67 OBC/million NO. Then in the hypothetical case load of 1 OBC/mn NH₃1 OBC/million NO N* will be the product of (1+0,67 OBC/million) on the inlet pressure in kilopascals, (absolute) divided by 2300 kPa. When determining the relative efficiency of gaseous nitrogen-containing promoters must use the same conditions at the entrance, which will be used in the process of obtaining ethylene oxide, because the relative efficiency to some extent may depend on the concentrations of other gases in the loading and temperature.

In the present invention, an acceptable range of concentrations of nitrogen-containing gas-phase promoter, expressed in N*, is from 1 to 20 OBC/million

In the prior art it is well known that gaseous listeriosis promoters, such as ethylchloride, vinyl chloride, ethylene dichloride, methyl chloride and other chlorinated hydrocarbons, can be added to increase the efficiency of the solid catalyst. It is also known that hydrocarbons, such as ethane, propane and ethylene, dechlorinate the surface of the solid catalyst and reduce the effectiveness of the chloride-containing promoters. Thus, in order to appropriately adjust the amount of chlorine that is present on the solid catalyst, Z* is a measure of the overall efficiency of chlorine-containing promoter is defined as

If ethylchloride is the only gaseous chlorine-containing promoter that is present at the input, ethylchloride equivalent is the concentration of ethylchloride in ABC/million When using other chlorine-containing promoter (concrete, vinyl chloride, methyl chloride or telengard) alone or in combination with ethylchloride, ethylchloride equivalent represents the sum of the concentrations of ethylchloride in ABC/m and the concentrations of other gaseous chlorine-containing promoter (fixed on its effectiveness as a promoter in comparison with ethylchloride). The relative effectiveness of non-ethylchloride promoter can be measured experimentally, replacing ethylchloride another promoter and determining the concentration of, the mu is necessary to achieve the same level of performance of the catalyst, what provides ethylchloride. For example (for further explanations), if desired concentration of ethylene in the reactor inlet for the implementation of equivalent efficiency in the performance of the catalyst, provide 1 OBC/million ethylthiourea 0.5 OBC/million, then ethylchloride equivalent to 1 OBC/mn of the ethylene dichloride will be 2 OBC/mn of the ethylene dichloride. Then in the hypothetical case load of 1 OBC/mn of the ethylene dichloride and 1 OBC/million ethylthiourea ethylchloride equivalent values Z* will be 3 OBC/million

Ethane equivalent is the sum of the concentration of ethane in mole%, and the concentrations of other hydrocarbons, is effective in the removal of chlorides from the catalyst, adjusted for their effectiveness dechlorination relative to ethane. The relative effectiveness of non-ethane hydrocarbon can be measured experimentally, replacing ethane using as declareroles agent to another hydrocarbon, and determining the concentration needed to obtain the same level of performance of the catalyst, which provides ethane. For example (for further explanations), if it is found experimentally that the ethylene concentration in the reactor inlet of 10.0 mol.% when dechlorination catalyst equivalent efficiency of 0.1 mol.% Ethan, then Ethan is the new equivalent of 10.0 mol.% ethylene will be 0.1 mol.%. Then ethane equivalent to a typical load at the inlet of the reactor containing 30,0 mol.% ethylene and 0.1 mol.% Ethan will be to 0.4 mol.%. If found that the hydrocarbon has a very weak dichloride action and is also present in low concentrations, then its contribution to the concentration of ethane equivalent when calculating Z* to be insignificant.

It is important that the relative efficacy of gaseous chlorine product and type declareroles hydrocarbon also measured in the conditions in the reactor used in the method.

In the present invention, an acceptable range of concentration of gaseous chlorine-containing promoter, expressed in Z*, is from 5 to 40 OBC/million

Although gaseous chlorine-containing promoter can be served as a single substance, after contact with the catalyst can be formed of other substances, which leads to the formation of the mixture in the gas phase. As a result, if the reaction gases are returned to the cycle, at the entrance of the reactor to form a mixture of substances. In particular, the return to the cycle of the reaction gases at the input can contain ethylchloride, vinyl chloride, ethylene dichloride and methyl chloride, even if the system serves only ethylchloride. The concentration of such chlorine-containing substances should be taken into account when calculating Z*. Also on the catalyst surface occurs R. the action of gaseous nitrogen-containing promoter, and compounds present in the gas returned into the cycle should be taken into account when calculating Z*.

While Z* depends on the concentration of individual hydrocarbons present in the loaded gas, N* does not depend on the concentration of hydrocarbons in the reactor at regular intervals. Although the present invention should not be understood as limited to any particular theory, it is believed that the hydrocarbon is less effective at removing nitrogen-containing particles present on the surface of the catalyst, compared to their efficiency in the removal of chlorine-containing particles present on the catalyst surface.

When the method of this invention include the use of catalysts, it is necessary to optimize the concentration at the inlet of both gaseous promoters, i.e. nitrogen-containing promoter and chlorine-containing promoter. Concentrations you can choose to optimize one or more of these performance catalyst, efficiency, activity (temperature), loss of efficiency or loss of activity (temperature), thus, there can be multiple Optima, depending on what aspects of the operating characteristics of the catalyst are of most importance to the user. It was found that optimal performance of the catalyst depending the on the concentrations of both gaseous promoters, i.e. some combination of promoters lead to much greater efficiency, activity or slower loss of activity than others. In particular, it was found that the combination of N* and Z*, where N*/Z* less than or equal to 1, provide the best performance characteristics.

For each catalyst, the optimum combination of N* and Z*, which gives the optimum performance will vary depending on the amount and type of solid promoter on the catalyst, reaction temperature, concentration of carbon dioxide in the reactor and the total quantity of ethylene oxide, from the first use of the catalyst as loss of its activity. Under certain reaction conditions, N* will vary from 1 to 20 ABC/m, and Z* from 5 to 40 OBC/million As a rule, in the case of N* values at the smaller end of the interval will be optimal at the beginning of the catalyst, when the temperature, the lifetime of the catalyst and the content of carbon dioxide, as a rule, are lower and will move toward the higher values at the end of the interval after the catalyst will work for some time, i.e. when the catalyst aging. Similarly, increases the optimal value Z*.

I believe that higher temperature increases the optimal value N*and Z*, while the aging of the catalyst increases on timum N*. Also believe that the current concentration of ethylene oxide has little effect on the optimum, in which the catalysts can be valid large values of N* with the formation of ethylene oxide in large quantities. Although the present invention should not be understood as limited to any particular theory, it is believed that higher N* and Z* are preferred at higher temperatures, since the particles on the surface of the formed nitrogen-containing promoter and chlorine-containing promoter, have less residence time on the catalyst surface, and/or resistance of individual particles on the surface depends on the temperature. Temperature dependence of several more for Z*than N*, N*/Z* should be reduced in case of an increase of a given reaction temperature, and the same applies to the content of carbon dioxide and the aging of the catalyst.

The optimal value N* also depends on the concentration of carbon dioxide in the reactor, and, as a rule, the higher the value of N* preferably with higher concentrations of carbon dioxide. The average concentration of carbon dioxide, i.e. the average of the concentrations of carbon dioxide at the inlet and outlet, affects the optimal value N* in a tubular reactor, while the concentration of carbon dioxide output has the greatest influence on the optimal value N* in a flow reactor with a mixer or reactor with back-mixing.

In similar conditions the solid catalyst containing large aggregate quantity EA will have higher optimum N*than the catalyst with smaller amounts accumulated EA.

Although the relationship N*/Z*less than or equal to 1, are preferred for the method according to the present invention, some of the interval relations are more preferred. For catalysts at the beginning of operation with average concentrations of carbon dioxide less than 1%, preferably N*/Z* in the range of 0.1 to 0.6, especially for high absolute efficiency and small loss of catalyst activity. For older catalysts after more roughly 70,000 pounds of ethylene oxide per cubic foot of catalyst for high efficiency and small loss of activity of the catalyst preferably the ratio N*/Z* 0,4-1,0. Activity can be increased by increasing the ratio N*/Z* outside of optimum efficiency.

When the concentration of carbon dioxide at the inlet of the reactor exceeds 2 mol.%, improved performance of the catalyst is possible to realize such high ratios of N*/Z*, as in 1.5.

When optimizing N*/Z* may be required to work for at least 24 hours after a change in operating conditions, to determine how the change affects the performance of the catalyst in the prescribed mode./p>

Although the present invention is described for use in preparation of ethylene oxide using the present invention in a manner similar to the method of producing ethylene oxide, it is possible to obtain a propylene oxide from propylene.

In commercially advantageous catalysts for production of ethylene oxide carrier containing silver and promoters must have the physical shape and strength for the correct flow of gaseous reactants, products, and ballast through the reactor, and at the same time preserves the physical integrity during normal operation of the catalyst. No significant damage or abrasion is highly undesirable, since such a failure can cause a drop in pressure and security problems. The catalyst must also be able to withstand considerable temperature variations in the reactor. The porous structure and chemical inertness of the media are also important factors that should be considered for optimum performance of the catalyst. Refractory materials, in particular alpha-alumina, have been used successfully as a carrier for catalysts receipt of ethylene oxide. You can also use other porous refractory carrier or materials as long as they are relatively inert in the presence of the tvii download reagents input for epoxidation, and the resulting epoxide, and capable of withstanding the conditions obtaining when the conversion catalyst. For example, the media can consist of alpha-aluminum oxide, silicon carbide, silicon dioxide, zirconium dioxide, magnesium oxide, various clays, and mixtures thereof. In the present invention the preferred medium consisting of alpha-alumina. The media containing the modifiers that improve the properties of alpha-alumina as a catalyst carrier, can also be used, and in some cases they may be preferred.

Suitable forms of media in this invention are any of a variety of forms, known for such catalysts carriers, including pellets, chunks, tablets, pieces, pellets, rings, spheres, wagon wheels, toroids with star-shaped inner and/or outer surfaces, with the size, suitable for use in reactors with a fixed layer. Normal commercial reactors fixed bed to obtain ethylene oxide usually in the form of multiple parallel long tubes (in appropriate case) O.D. 1-3 inches and a length of 15-45 feet, filled with a catalyst. In such reactors, fixed bed, it is desirable to use a carrier having particles of rounded shape, such as, for example, spheres, pellets, rings, and t is blecki, with diameters from 0.1 inch to 0.8 inch.

To obtain a carrier suitable for use in the catalysts of receipt of ethylene oxide, it is possible to use well-known methods. For example, alpha-axinellidae media purity of at least 95% can be obtained by compounding (mixing) raw materials, pressing, squeezing, drying and high temperature annealing. In this case, raw materials, typically include one or more powdered alpha-alumina with different properties, the material type of clay that can be added as a binder to achieve physical strength, and burnable material (usually organic compound), which can be used in the mixture to obtain the desired porosity after removal during the stage of annealing. The content of impurities in the obtained media depends on the purity of the source materials and the degree of volatility during the stage of calcination. Common impurities include silicon dioxide, oxides of alkali and alkaline earth metals, and trace amounts of additives containing metals and/or nonmetals.

alpha Axinellidae media obtained in this way preferably has a pore distribution, where

less than 20 vol.% (preferably 0-5%vol.) pore has a diameter of m is it to 0.1 μm;

5-30 vol.% (preferably 5-20 vol.%) pore has a diameter of 0.1-0.5 μm;

7-30% vol. (preferably 10-25 vol.%) pore has a diameter of 0.5-1.0 microns;

more than 10% vol. (preferably 10-40 vol.%) pore has a diameter of 1.0 to 10 microns;

more than 20 vol.% (preferably 30-55%vol.) pore has a diameter of 10-100 μm; and

4-20% vol. (preferably 6-20%vol.) pore has a diameter of at least 100 microns.

Another way to get media properties, particularly suitable for use catalyst receipt of ethylene oxide, involves mixing the boehmite (AlOOH) and/or gamma-aluminum oxide, peptization of aluminum oxide in an acidic mixture containing halide anions (preferably fluoride anions) to obtain pepsirefresh halogenated alumina, forming (for example, by extrusion or pressure) pepsirefresh halogenated alumina to obtain a molded pepsirefresh halogenated alumina, drying the molded pepsirefresh halogenated alumina to obtain dry pepsirefresh halogenated alumina, and calcining the dry pepsirefresh halogenated alumina to obtain pellets of alpha-oxindolimine media that is illustrated in the examples below.

alpha Axinellidae carrier obtained by the method described above, preferably have the t specific surface area, at least 0.5 m²/g (preferably from 0.7 m²/g to 10 m²/g), porosity of at least 0.5 cm³/g (preferably from 0.5 cm³/g to 2.0 cm³/g), purity (except for any of the modifying component), at least 99 wt.% alpha-aluminum oxide and the average pore diameter of from 1 to 50 μm. In this case, alpha axinellidae media contains particles, each of which has at least one essentially flat major surface of the flake or lamellar morphology, coming to the hexagon (and some particles have two or more flat surfaces), at least 50% (by number) has base size less than 50 microns.

The catalysts to obtain accelerated, such as ethylene oxide or propylene oxide can be obtained on the media, impregnating the carrier with a solution of one or more compounds of silver, which is well known in the art. Simultaneously impregnated with silver to silver impregnation and/or after impregnation with silver can be impregnated with one or more promoters. Upon receipt of such a catalyst carrier impregnated with (one or more times by one or more solutions of compounds of silver in sufficient degree to cause the silver to the medium in amounts that calable is between 1% to 70%, preferably from 5% to 50%, most preferably from 10% to 40%, by weight of the catalyst.

The particle size of silver important but is not strictly critical. Suitable silver particles may have a size in the range from 100 to 10000 Å.

There are a number of known promoters, i.e. materials which, when they are present in combination with certain catalytic materials, for example, silver, is favorable for one or more aspects of the performance of the catalyst or act otherwise as promoting ability of a catalyst to create the desired product, such as ethylene oxide. Such promoters themselves are generally not considered to be catalytic materials. It is shown that the presence of such promoters in the catalyst contributes to one or more favorable action on the performance of the catalyst, for example, increase of the speed or quantity of the desired product, the lower the temperature required to achieve a suitable reaction rate, the decrease in the velocity or the number of adverse reactions, etc. As described above, the promoters may be present in the catalyst in solid form or it can be added in gaseous form in the reaction system. Gaseous promoters are described as gas-phase modifiers, inhibitors and enhancers. To produce the arts and method of the present invention for optimum performance of the catalyst is also required additional gas-phase promoter, containing nitrogen. In the reactor takes place simultaneously competing reactions, and a critical factor in determining the efficiency of the whole process is the degree of control over such competing reactions. The material, known as the promoter of the desired reaction, it may be another reaction inhibitor, for example, the combustion reaction. It is essential that the influence of the promoter to the reaction in General is favorable to efficiently obtain a desired product, such as ethylene oxide.

It is desirable that the silver and one or more promoters were distributed on the carrier relatively evenly. The preferred procedure for the deposition of silver catalytic material and one or more promoters includes (1) impregnation of the porous carrier of the present invention with a solution containing a solvent or solubilizer, a complex of silver and one or more promoters, and (2) subsequent processing of the impregnated carrier to convert salt to metallic silver and effective deposition of silver and promoter(s) on the outer surface and the inner surface of the pores of the support. Deposition of silver and solid promoters, normally carried out by heating the medium at elevated temperatures for evaporation of liquid from the carrier and efficient deposition of silver and promoter(s) in the morning and the outer surface of the carrier. The impregnated carrier is the preferred method for the deposition of silver, because silver is used more efficiently than in the procedures of the coating, and the latter, as a rule, unable to exercise significant deposition of silver on the inner surface of the carrier. In addition, the catalysts coated more prone to loss of silver due to mechanical abrasion.

Containing silver solution used for impregnation of the carrier preferably contains a compound of silver in the solvent or complexing agents and/or solubilizer, such as, for example, solutions of silver described in the prior art. The specific connection of silver you can choose, for example, from among complexes of silver, silver nitrate, silver oxide or silver carboxylates such as acetate, oxalate, citrate, phthalate, lactate, propionate, butyrate and silver salts of higher fatty acids. The complex of silver with amines is the preferred form of silver for use in the present invention.

You can use a variety of solvents or complexing agents/soljubilizatory to solubilize the silver to the desired concentration in the impregnating medium. Of them are suitable for this purpose are lactic acid; ammonia; alcohols, such as ethylene glycol; amines and aqueous mixtures of amines.

Example is, Ag₂O can be dissolved in a solution of oxalic acid and Ethylenediamine to about 30 wt.%. Vacuum impregnation with a solution of the carrier with a porosity of approximately 0.7 cm³/g typically results in a catalyst containing about 25 wt.% silver relative to the total weight of the catalyst. Accordingly, if you want to obtain a catalyst with a load of silver more than 25 or 30% or more, may require, as a rule, to expose the media, at least two or more successive impregnation with silver, with promoters or without them, until the media will not settle right amount of silver. In some cases, the concentration of silver salts in solutions when the last impregnation is higher than the first. In other cases, an approximately equal amount of silver precipitated during each impregnation. Often to achieve the same deposition at each impregnation in solution for subsequent impregnation may require a higher concentration of silver than the concentration in the solutions for the initial impregnation. In other cases, when the initial impregnation of the carrier precipitated a greater quantity of silver than the amount deposited during subsequent impregnation. For each impregnation may be followed by a calcination or other procedures to give the insoluble silver the property.

The catalysts used in the method according to the present invention, contain at least one or more promoters to improve the performance of the catalyst, for example, to increase the efficiency or decrease the combustion of ethylene oxide or impact on the activity. Such promoters or modifiers, usually represented as chemical compounds.

Used in this description, the term "connection" refers to the combination of a specific element with one or more other elements by surface and/or chemical bonding, such as ionic and/or covalent and/or coordination bond. The term "ion" or "ion" refers to an electrically charged chemical particle; and "cationic" or "cation" is positive and "anionic" or "anion" are negative. The term "oceniony" or "oxyanion" refers to a negatively charged particle that contains at least one atom of oxygen combined with another element. Thus, oxyanion is an oxygen-containing anion. It should be borne in mind that the ions do not exist in a vacuum, but are combined with balancing the charge of the counterions.

The catalysts used in the method according to this invention, are a type containing at least one increase the effectiveness the awn salt of a pair of redox of polyreactive, and used in the presence of gaseous nitrogen-containing component capable of forming a gaseous amplifying the effectiveness of the participant pairs of redox of polyreactive under the reaction conditions. The term "redox polyreactive" in this case is defined as denoting polyreactive like half-reactions represented by the equations presented in tables normal recovery or oxidation potentials, also known as the potentials of normal or separate electrodes, of the type shown, for example, in "Handbook of Chemistry", N.A. Lange, Editor, McGraw-Hill Book Company, Inc., pages 1213-1218 (1961), or in "CRC Handbook of Chemistry and Physics", 65^thEdition, CRC Press. Inc., Boca Raton, Fla., pages D155-162 (1984). The term "a pair of redox of polyreactive"refers to pairs of atoms, molecules or ions or their mixtures that undergo oxidation or restore such equations half-reactions. Terms such as "couples the redox of polyreactive" used in this description as including such members of the class of substances that provide the desired performance and not the mechanism occurring chemical transformations. Preferably, such compounds, when they are associated with the catalyst in the form of salts participants pair of polyreactive, are with the Lee, in which the anions are oxy-anions, preferably an oxy-anions of polyvalent atoms; i.e., the atom of the anion is bound oxygen that can exist when associated with a dissimilar atom, in different valence States. Potassium is the preferred cation, although it can also work the cations sodium, rubidium and cesium, and the preferred anions are nitrate-, nitrite - or other anions that can undergo substitution or other chemical reaction to form the nitrate anions in the conditions of the epoxidation. Preferred salts are KNO₃and KNO₂and KNO₃the most preferred. Used in this description, the term "salt" does not imply that the anionic and cationic components of salt is associated or linked in the solid catalyst, but implies only that the catalyst under the reaction conditions present in some form both components.

Salt of the pair of redox of polyreactive added to the catalyst in a quantity sufficient to increase the efficiency of the epoxidation reaction. The exact amount will vary from these variables, used as the gaseous efficiency-enhancing member of the redox of polyreactive and its concentration, the concentration of other components in the gas f is ze, the amount of silver contained in the finished catalyst, and the time of deposition of the promoter, the surface area of the carrier, the process conditions, for example, space velocity and temperature, and morphology of the media. On the other hand, you can also add a suitable previous connection, so that the right amount of salt participant redox of polyreactive is formed in the catalyst in the epoxidation conditions, especially during the reaction with one or more gaseous components. However, as a rule, a suitable range of concentration of the added reinforcing salt or its predecessor, is designed for the cation is 0.01-5 wt.%, preferably 0.02 to 3 wt.% relative to the total weight of the catalyst. Most preferably the salt is added in the amount of 0.03 to 2 wt.%.

The preferred gaseous efficiency-enhancing participants pairs of redox of polyreactive are compounds containing the element can exist in more than two valence States, preferably nitrogen, and another element, which is preferably oxygen. Examples of preferred gaseous efficiency-enhancing participants pairs of redox of polyreactive include at least one connection among NO, NO₂N₂O₄ N₂O₃or any gaseous substance capable of forming in the conditions of the epoxidation one of the above gases, in particular NO and NO₂. As the gaseous efficiency-enhancing compounds, the most preferable is NO.

Although in some cases in the reaction system is preferable to use members of the same couple redox of polyreactive, i.e. as efficiency-enhancing salt of a member associated with the catalyst and gaseous participant in the incoming flow, as, for example, in a preferred combination of potassium nitrate and nitric monoxide, it is not necessary in all cases to achieve satisfactory results. In the same system, you can also use other combinations, such as KNO₂/N₂O₃, KNO₃/NO₂, KNO₃/N₂O₄, KNO₂/NO, KNO₂/NO₂. In some cases, salt and gaseous participants can be found in different half-reactions, which represent the first and last reactions in a series of equations of the half-reactions common reaction.

In addition, at least one salt of a pair of redox of polyreactive the catalyst may additionally contain other solid promoters. For example, additional promoters may include the connection is to be placed, containing alkali metals, alkaline earth metals, halides, such as fluorides and chlorides, and the oxy-anions of the elements other than oxygen, with atomic numbers 5-83 groups 3b-7b and 3A-7a of the Periodic table, or mixtures thereof. (References to the Periodic table in this description will correspond to the table on the inner side of the cover in the published Chemical Rubber Company, Clevlend, Ohio, CRC Handbook of Chemistry and Physics, 46^thEdition). These compounds can be added to the catalyst in the active form or any other form, which becomes active particles upon receipt and application of the catalyst, and may exist in the catalyst in one or more forms.

Another class of promoters that can be added to the catalysts applicable in the method according to the present invention, includes manganese components. In many cases, manganese components can enhance the activity, efficiency and/or stability of the catalysts. Manganese particles, which provide enhanced activity, efficiency and/or stability, are not defined and can be an added component or a component that is formed during the preparation of the catalyst or during the application of the catalyst. Manganese components include, but are not confined listed, manganese acetate, ammoniumsulfate manganese, CIT is at manganese, ditional manganese, manganese oxalate, manganese nitrate, manganese sulfate and manganate-anion, for example, the permanganate anion. For stabilization of the manganese component in the impregnating solution may need to add chelat forming compounds such as ethylenediaminetetraacetic acid (edtc), which serves to preserve the mn containing ion in the solution until they impregnate, and turns into a solid form in the catalyst.

In any case, the promoters are provided on the solid catalyst in promoting amount. Used in this description, the term "promoting amount" for some component of the catalyst refers to the amount of such component, that works effectively, ensuring the improvement of one or more of the catalytic properties of this catalyst when compared to a catalyst not containing the specified component. Examples of catalytic properties are, inter alia, the validity of (resistance to deviation from the norm), selectivity, activity, conversion, resistance and output. Specialist in the art it should be borne in mind that one or more catalytic properties can be enhanced "promoting amount", while other catalytic properties can be improved or may not improve or even worsen. Also when edue to keep in mind what different catalytic properties can be enhanced in different operating conditions. For example, a catalyst with improved selectivity under one set of operating conditions may work with a different set of conditions, when will manifest improvement activities, rather than selectivity, and the operator unit for production of ethylene oxide is deliberately to change working conditions in order to take advantage of some catalytic properties even at the expense of other catalytic properties, in order to maximize profits, given the costs of raw materials, energy costs and costs for removal of by-products.

On promoterwise action provided by the promoters may be influenced by a number of factors, such as, for example, reaction conditions, methods of preparation of the catalyst, the surface area and porous structure and chemical properties of the surface of the carrier, the content of silver and copromotor in the catalyst, the presence of other cations and anions in the catalyst. The presence of other promoters, activators, stabilizers, enhancers, or other component that improves the properties of the catalyst, may also affect the promoting action.

The method of the present invention using silver catalysts particularly suitable for use in preparation of ethylene oxide by the method of vapor-phase oxidation of the ethyl whom and molecular oxygen in the process on the basis of oxygen, where as the source of the oxidizing agent used high purity (>95 mol.%) oxygen, see Kirk-Othmer'sEncyclopedia of Chemical Technology, 4^thEd. (1994), Volume 9, p. 930-934.

Conditions for the epoxidation of ethylene

For testing of the catalyst in the following examples use the standard autoclave with a reverse mixing with reuse gases. As reactors employ well-known bottom-agitated autoclaves with a reverse mixing, shown in figure 2 in the work of J.M. Berty, entitled "Reactor for Vapor Phase-Catalitic Studies", Chemical Engineering Progress, Vol.70, No.5, pages 78-84, 1974. Conditions at the inlet, including load, expenses, and temperature, are given in each example.

Pressure support level 275 f/d²(pounds per square inch), and the total flow rate at the inlet is maintained at a level of from 8 to 22 SCFH (cubic feet per hour). SCFH refers to cubic feet per hour at normal temperature and pressure, namely 0°C and one atmosphere. Temperature (°C), the percentage of ethylene oxide output and catalytic efficiency gain as features describing the performance of the catalyst. In all examples, the source gas mixture containing ethylene, oxygen, carbon dioxide (optional), ethane (optional), ethylchloride, monoxide nitrogen and nitrogen as ballast gas.

The testing of catalysts in autoclaves for Luchesa the following: in the autoclave with a reverse mixing load 40 or 80 cm ³catalyst and note the weight of the catalyst. Autoclave with a reverse mixing heated to reaction temperature under a nitrogen flow of 10 or 20 SCFH supplied by the centrifugal pump operating at 1500 rpm Then the flow of nitrogen was stopped, and the reactor enter the stream above the source gas mixture. Then full gas flow at the inlet to regulate the right amount. Then adjust the conditions to conditions that are required for testing. The concentration of epoxide at the output is controlled to obtain a predetermined value when the catalyst reaches its peak performance in the prescribed mode. Then you can get the efficiency of a catalyst to obtain the ethylene oxide and the rate of deactivation (temperature rise and fall of efficiency). In determining the activity and efficiency of the process and the catalyst should be in terms of the current mode.

The standard deviation of a single test result in accordance with the process described above, the reflecting efficiency of the catalyst is 0.5% in terms of efficiency. A typical standard deviation of a single test result in accordance with the above procedure, reflecting the activity of the catalyst is 2°C. of Course, the standard deviation will depend on the quality of equipment and accuracy of the methods, the COI is lsemaj testing, and, thus, will vary. I believe that these standard deviations are applicable to the results of the tests described in this description.

Obtaining catalyst

The media is subjected to vacuum impregnation of the first silver-containing impregnating solution, typically containing 30 wt.% silver oxide, 18 wt.% oxalic acid, 17 wt.% Ethylenediamine, 6 wt.% of monoethanolamine and 27 wt.% of distilled water. The first impregnating solution typically receive (1) mixing 1.14 parts of Ethylenediamine (especially pure) with 1.75 parts of distilled water; (2) adding 1.16 parts of the dihydrate of oxalic acid (chemically pure) to aqueous solution of ethylene diamine so that the solution temperature did not exceed 40°C, (3) gradually adding 1.98 parts of silver oxide and (4) by adding 0.40 parts of monoethanolamine (free of Fe and Cl).

The carrier impregnated in a glass or stainless steel cylindrical vessel of suitable size, provided with a suitable shut-off valves for impregnation of the carrier under vacuum. A suitable separating funnel, which is used as a tank for impregnating solution, is inserted through a rubber stopper in the upper part of the vessel for impregnation. Vessel for impregnation containing catalyst, pumped for 10-30 minutes to about 1-2" RT. article, absolute, after che is about impregnating solution is added slowly to the media, opening the stopcock between the separating funnel and the vessel for impregnation. After the entire solution will be transferred to the vessel for impregnation (~15 seconds), the vacuum is shut off and pressure lead to atmospheric. After adding a solution of the carrier leave immersed in the impregnating solution at ambient temperature for 5-30 minutes, and then the excess solution is drained within 10-30 minutes.

Then impregnated with silver media calcined, as described hereinafter, to effect the recovery of silver on the catalyst surface. The impregnated carrier is distributed evenly on the mesh trays of stainless steel wire, which are then placed on the conveyor belt stainless steel (spiral weave) and transported through a square 2"x2", thermal zone for 2.5 minutes, or use equivalent terms when working with conveyor larger. In thermal zone support 500°C, passing hot air upward through the conveyor and the catalyst particles with a speed of 266 cubic feet per hour (SCFH). After annealing in thermal zone, the catalyst is cooled in the open air to room temperature and weighed.

Then the carrier is impregnated with silver, is subjected to vacuum impregnation second silver-containing solution containing a solution of amine oxalate is elebra, and the promoters of the catalyst. The second solution for impregnation consists of just drained solution from the first impregnation with the addition of fresh aliquot of the first solution, or use the new solution. The promoters added under stirring, to dissolve, add in quantities sufficient to achieve the desired target levels in the finished catalysts. Promoters and stabilizers include pure potassium nitrate, a solution of manganese-add (K₂Mn etc) and a solution of diammonium-etc. One equivalent of diammonium-add added with manganese promoter to enhance stability of the mn containing ion in the impregnating solution.

Impregnation stage, draining and annealing in the case of this second impregnation carried out similarly specified stages during the first impregnation.

Double-impregnated catalyst, which is prepared catalyst, weighed again, and on the basis of gain in mass media with a second impregnation calculate wt.% silver and the concentration of the promoters (the results are given in table). In some cases, using equipment and methods appropriate scale shall obtain catalyst in a scale larger than described in this description. Then, the finished catalyst used in the epoxidation reaction of ethylene, the results of which are given in Arah.

The properties of the original materials carriers and catalysts are given in tabl

Example 1

Work with two 40-cm³the catalyst samples 1, each weight of 31.3 g, in two different reactors. In both tests the initial conditions at the inlet are to 8.0 mol.% About₂, 30,0 mol.% With₂H_{4 , 5,0 OBC/million ethylchloride and 5.0 OBC/million NO temperature 220°C and the total flow rate in the reactor 9,5 SCFH. In the reactor at the inlet does not serve either carbon dioxide or ethane. The temperature was then raised to 240°C, and on day 5 increase the content With2H6to 0.27 mol.%. Further changes are given in tables II and III; the ethylene oxide in the tables indicated by the abbreviation EA. In the test And, where the ratio N*/Z* support at the level of less than 1, higher efficiency and more stable.}

Example 2

Work with the 80-cm³sample kata is Isadora 1 weights and 62.6 g in the reactor without feeding CO ₂(test). In a smaller reactor working with a 40-cm³the sample of catalyst 1 by weight of 31.3 g in the same conditions at the input (test A). Other conditions at the inlet are given in .IV; ethylchloride indicated by the abbreviation ECl. In both cases, the change in the amount of ethane in the input has no effect on the efficiency up until regulate the concentration of ethylchloride to maintain a constant Z*, and hence N*/Z*.

Example 3

The sample of catalyst 1 in 80 cm³mass 62,9 g experience in the reactor under the conditions specified in .V; ethylchloride indicated by the abbreviation ECl. .V shows the optimization of N*/Z* for efficiency due to changes in the concentration of ECl. In the days 8-12 showing values of Z*. The catalyst shows long-term stability at values of Z* and N*, the final selected in day 12, which demonstrates the effectiveness on days 17 and 23, which is somewhat reduced due to aging of the catalyst, but remains relatively high.

Example 4

With two 40-cm³samples of catalyst 2 each weight of 31.3 g simultaneously in different reactors. In both tests the initial conditions at the inlet are to 8.0 mol.% About₂, 30,0 mol.% With₂H₄, 5,0 OBC/million ethylchloride and 5.0 OBC/million NO temperature 220°C and the total flow rate in the reactor 9,5 SCFH. In the reactor at the input of first serves no carbon dioxide or ethane. In the first three days the temperature was raised to 245°C. Far the major changes are listed in tables VI and VII. It is clear that the selectivity and activity of catalyst 2 in the test And, where the ratio N*/Z* is less than 1, higher than in the test, where the ratio is greater than 1.

1. The method of producing ethylene oxide by the epoxidation of ethylene in a reactor having at least one inlet for the introduction of raw materials and additives and at least one outlet for the discharge of ethylene oxide, including
A) interaction of a raw material containing ethylene, oxygen and, optionally, ethane, in the presence of a catalyst, with the specified catalyst contains a catalytically effective amount of silver on an inert refractory solid carrier and at least one efficiency-enhancing salt of a member couples the redox of polyreactive;
B) adding to the specified raw two-component gas-phase promoter containing at least one chlorine-containing component selected from the group consisting of ethylchloride, methyl chloride, vinyl chloride and ethylene dichloride; and at least one nitrogen-containing component selected from the group consisting of nitric monoxide and other compounds capable of reaction conditions to form, p is at least one gaseous efficiency-enhancing member of a pair of redox of polyreactive, including NO, NO₂N₂O₃or N₂O₄;
C) receiving with the same catalyst more about 1.1 kilometricka tons per cubic meter of catalyst;
D) specifying the amount of each component of the specified gas-phase promoter to maintain the relationship N* Z* in the range from 0.4 to 1.0, where N* represents the equivalent of nitrogen monoxide in units OBC/million, with a numerical value from 1 to 20 OBC/mn, where if the nitric monoxide is the only gaseous nitrogen-containing component present in the input, N* represents the concentration of nitrogen oxides at the entrance to OBC/million multiplied by the inlet pressure in kilopascals, absolute, divided by 2300 kPa, and if you use one or more other gaseous nitrogen-containing components, alone or in combination with nitric monoxide, the equivalent of nitrogen monoxide represents the sum of the concentration of nitrogen monoxide in ABC/m and the concentration of each of the other gaseous nitrogen-containing components (adjusted for its effectiveness as a promoter compared with the nitric monoxide), multiplied by the inlet pressure in kilopascals, absolute, divided by 2300 kPa, and

with those who Noah is from 5 to 40 OBC/million where, if ethylchloride is the only gaseous chlorine-containing component present at the input, ethylchloride equivalent is the concentration of ethylchloride in ABC/million, and if you use one or more other chlorinated components, alone or in combination with ethylchloride, ethylchloride equivalent represents the sum of the concentrations of ethylchloride in ABC/m and the concentration of each of the other gaseous chlorine-containing components (adjusted for its effectiveness as a promoter in comparison with ethylchloride), and where the ethane equivalent is the sum of the concentration of ethane in mole% and the concentration of each of the other hydrocarbons, is effective in removing chloride from the catalyst (adjusted for its effectiveness in the removal of chloride compared to ethane); and
(E) regulating the temperature of the specified reactor from 200 to 300°C, and inlet pressure specified reactor from 1000 to 2500 kPa (absolute) and the concentration of carbon dioxide in the specified entry from 0 to 2 mol.%.

2. The method according to claim 1, where the specified efficiency-enhancing salt is a nitrate or potassium nitrate rubidium.

3. The method according to claim 1, where the specified silver is present in an amount of 5 to 50 wt.% relative to the weight of the catalyst.

4. The method according to claim 1, where the specified refractory solid carrier includes alpha is xed aluminum.

5. The method according to claim 4, where the specified alpha-oxide-aluminum carrier has a morphology comprising fused plates.

6. The method according to claim 1, where the temperature specified regulate reactor in the range from 210 to 280°C.

7. The method according to claim 1, where the inlet pressure specified regulate reactor in the range from 1800 to 2500 kPa (absolute).