TW201404467A - Method of making a manganese-containing supported silver catalyst - Google Patents

Abstract

A method of making a manganese-containing supported silver catalyst intermediate is provided. The method includes preparing a first solution comprising a manganese component and a complexing agent which is combined with a second solution comprising silver to form an impregnation solution. A pH of the first solution at any time during or after the preparation of the first solution is less than or equal to 7. A support is subsequently impregnated with at least a portion of the impregnation solution to form the catalyst intermediate. The impregnation solution has a pH of greater than 7.

Description

Method for producing manganese catalyst supported by manganese

The present invention relates to a process for producing a manganese catalyst supported on manganese.

Ethylene oxide can be industrially produced by direct epoxidation of ethylene from a supported silver-containing catalyst at elevated temperatures. Since the catalyst is an important element in the direct oxidation of ethylene to ethylene oxide, much effort has been put into improving other aspects of catalyst stability, efficiency, selectivity and/or catalyst performance in ethylene oxide production.

The use of suitable promoters is an effective and proven means of enhancing catalyst performance in the production of ethylene oxide and is well known to those skilled in the art. There are at least two types of accelerators - solid accelerators and gas promoters. The solid promoter can be incorporated into the catalyst prior to use of the catalyst as part of the support (i.e., the support) or as part of the silver component applied to the support (i.e., the support). Typically, the silver-supported catalyst is prepared by immersing the support in an impregnation solution containing silver and optionally one or more promoters.

U.S. Patent No. 5,504,053 describes a silver-containing supported catalyst containing a manganese-containing component in an amount that enhances stability, efficiency and/or activity. The amount of manganese present in the silver-supported catalyst is at least 20 parts per million (ppmw) or at least 60 ppmw, preferably 70 ppmw to 1000 ppmw, more preferably 80 ppmw to 500 ppmw, and ppmw is based on the total weight of the catalyst. Weight calculation.

WO2005/023417A1, WO2008/054564A1 and US2007/0111886 describe the addition of diammonium ethylenediaminetetraacetate and a manganese-containing component to stabilize the manganese-containing component of the impregnation solution.

In US 2007/0032670, an accelerator and a solubilizer are added to an impregnation solution comprising pure potassium nitrate, manganese diamine tetraacetate (K ₂ MnEDTA) solution and diammonium ethylenediamine tetraacetate solution. One equivalent of diammonium ethylenediaminetetraacetate and a manganese promoter are added to increase the stability of the manganese-containing ions in the impregnation solution.

EP 480,537 A1 discloses the preparation of a solid manganese complex of tetrahydrate of ethylenediaminetetraacetate II (H ₂ MnEDTA) which can then be introduced into an impregnation solution. EP 480,537 A1 discloses that a metal-containing promoter comprising manganese can be present in the form of a complex in a silver-containing impregnation solution prior to association with the support. Preferably, the complexes are effective to enhance the solubility of the metal-containing promoter in the impregnation solution or solution precursor by including (a) in the silver-containing impregnation solution or (b) in the solution containing the metal-containing promoter precursor. And/or one or more complexing agents are present in an amount effective to form a complex with at least one metal species. The term "solubility stability" is defined as a measure of the ability of a metal-containing promoter to remain in solution over time: the longer the time in solution, the higher the solubility stability of the metal-containing promoter. As described in EP 480,537 A1, enhanced solubility and/or solubility stability of a metal-containing promoter solution means that the solution does not contain a metal-containing promoter in a miscellaneous form.

Typically, a stoichiometric amount of the manganese-containing component corresponding to the desired target level is provided in the impregnation solution used to impregnate the carrier. However, the impregnated support or catalyst may often not have the desired target manganese content, or it exhibits variability in the amount of manganese. If the obtained catalyst exhibits a variability of about 10% or more than the desired target content, the performance of the catalyst is adversely affected. ring. Therefore, there is a need to provide a manganese component in a supported silver catalyst in a more simplified, industrially feasible, and more reliable manner.

According to a particular embodiment of the invention, the variability in the amount of manganese on the manganese-supported silver catalyst can be reduced by following the process of the invention for producing a manganese catalyst-supported silver catalyst intermediate. The method includes the step (i) of preparing a first solution comprising a manganese component and a complexing agent. The pH of the first solution is less than or equal to 7 at any time during or after step (i). In step (ii), the first solution is combined with a second solution comprising silver to form an impregnation solution. In step (iii), the support is subsequently impregnated with at least a portion of the impregnation solution to form a catalyst intermediate. The pH of the impregnation solution is greater than 7. Catalyst performance, such as efficiency, activity, aging, and/or other aspects of catalyst performance, can be improved by reducing the variability in the amount of manganese on the catalyst.

Figure 1 is a graph of the variability of the amount of manganese in the impregnation solution relative to the batch of the impregnation solution prepared using the prior art method, and is expressed as a percentage change of the manganese content relative to the desired target content; Figure 2 is the manganese in the impregnation solution. A graph of the variability of the amount relative to the batch of the impregnation solution prepared using the specific examples of the present invention, and expressed as a percentage change of the manganese content relative to the desired target content; FIG. 3 is a prior art method Example 4* and the present invention. Comparison of the potency of the catalyst batch prepared by the method of Example 3; and FIG. 4 is a comparison of the change of the amount of manganese in the batch of the manganese-containing oxalic acid amine solution prepared by using the prior art method Example 5* and the method of Example 4 of the present invention. .

The supported silver catalyst containing the manganese promoter exhibits enhanced stability, activity and/or selectivity in the epoxidation of ethylene to ethylene oxide compared to a silver catalyst in which no manganese promoter is present. Surprisingly, it has been found that when a first solution comprising a manganese component and a binder is combined with a second solution comprising silver to form an impregnation solution, the catalyst obtained by impregnating the impregnation solution and the use thereof do not include preparation of manganese. The catalyst obtained by the impregnation solution prepared by the method of the first solution of the component and the wrong agent shows better performance characteristics. In one embodiment, the amount of manganese on the manganese-supported silver catalyst provided by the process of the present invention is less variable than prior art processes that do not include the preparation of the first solution.

In a typical epoxidation reaction, an olefin such as ethylene is reacted with oxygen or an oxygen-containing gas in the presence of a supported silver catalyst in a reactor to form an alkylene oxide, such as ethylene oxide. The epoxidation reaction can be characterized by "activity", "productivity" and/or "selectivity" of the epoxidation reaction.

The activity of the epoxidation reaction can be quantified in a number of ways, one way being to maintain a substantially constant reactor temperature, relative to the inlet stream of the reactor (the percentage of moles of alkylene oxide in the inlet stream is typically (but not necessarily) approximate 0%), the percentage of moles of alkylene oxide contained in the outlet stream; and another way is the temperature required to maintain the rate of production of a given alkylene oxide. In many cases, the activity is measured over a period of time based on the percentage of moles of alkylene oxide produced at a specified constant temperature. Activity can be defined as the rate of reaction in the reactor in the direction of formation of alkylene oxide per unit volume of catalyst. Alternatively, the activity may be measured as a function of the temperature required to maintain an alkylene oxide of a specified constant molar percentage, such as ethylene oxide, given other conditions such as pressure and total moles of feed. .

The productivity of the reaction is a measure of the rate of reaction normalized by the amount of catalyst. In Xu In many cases, productivity can be expressed as the number of moles or kilograms of alkylene oxide produced per volume of catalyst per hour (measured by the volume of the reactor charge). In some cases, productivity can be expressed as the percentage of moles of alkylene oxide in the reactor outlet stream at specified processing conditions, such as space velocity.

The "selectivity" of an epoxidation reaction is synonymous with "efficiency" and refers to the relative amount (fraction or percentage) of an olefin that is converted or reacted to form a specific product. For example, "efficiency to alkylene oxide" refers to the percentage of moles of olefins that are converted or reacted to form alkylene oxides.

As used herein, "deactivation" or "aging" refers to the permanent loss of activity and/or efficiency, ie, the reduction in activity and/or efficiency cannot be restored. A lower passivation rate is generally required.

The term "compound" as used herein refers to a surface and/or chemical bond (such as ionic bonding and/or covalent bonding and/or coordination bonding) of a particular element and one or more different elements. The combination. The term "ionic" or "ion" refers to a chemical moiety with a charge; "cationic" or "cation" is positive and "anionic" or " Anion is negative. The term "oxyanionic" or "oxyanion" refers to a negatively charged moiety containing at least one oxygen atom and another element. The oxyanion is therefore an oxyanion. It will be appreciated that the ions are not present in the vacuum and are present in combination with the charge balance relative to the ions when added to the catalyst as a compound.

The term "solution" as used herein refers to a clear solution, and includes both suspensions and colloidal solutions.

The term "support" as used herein refers to the usual use in the preparation of a support. A carrier or carrier of the epoxidation catalyst. "Improved support" means a carrier that has been impregnated with silver or has been deposited with silver. The term "catalyst intermediate" as used herein refers to steps (i) through (iii) of a method for producing a silver-containing catalyst intermediate containing manganese, in accordance with a specific example of the present invention, A carrier that is impregnated or deposited with at least manganese and silver. The "catalyst intermediate" is also referred to as "the silver catalyst intermediate supported by manganese."

The term "catalyst" as used herein refers to a finished catalyst obtained after further processing of the "catalyst intermediate". "Catalyst" is also referred to as "manganese-supported silver catalyst" which is prepared according to the specific examples of the present invention and which can be directly fed into the reactor for commercial ethylene oxide production.

The term "variability" as used herein is defined as the change or deviation of the amount of manganese deposited or present on a catalyst intermediate or finished catalyst or in an impregnation solution relative to the desired target content. In one embodiment, the variability is expressed as a percentage change in the amount of manganese relative to the desired target content.

As used herein, the term "pH of the first solution at any time during or after step (i)" means a combination of a manganese component and a complexing agent. The pH of the first solution at at least one subsequent time point. It does not mean "any and all time" after the combination of the manganese component and the complexing agent.

The manganese component (manganese promoter) can be provided in various forms, for example in the form of a covalent compound such as manganese dioxide, a cation or an anion such as a manganate anion. The manganese component present in the first solution may include, but is not limited to, manganese acetate, manganese ammonium sulfate, manganese citrate, manganese disulfate, manganese oxalate, manganese manganese nitrate, manganese sulfate, and manganate anions, such as permanganese. Acid anions, manganate anions and the like. Mixtures of manganese components can also be used. The manganese species which enhances the activity and/or stability are not determined and may be components added or components produced during catalyst preparation or during use as a catalyst. Although the manganese species that provide advantageous properties to the catalyst are not specifically known, the manganese component is added to the form in the form of permanganate ion (MnO ₄ ) ^1- and/or manganese cation (eg, Mn(NO ₃ ) ₂ ). Generally acceptable results are obtained in a solution. In addition, the different manganese components added may also have different optimum concentrations to achieve these results. Typically, the manganese in the manganese component has an oxidation state of +2, +3, +4 and/or +7, preferably +2, +3 and/or +7.

The desired amount of catalyst intermediate or catalyst manganese promoter may be determined based on the silver content of the catalyst intermediate or catalyst, the amount and type of other promoters present, and the chemical and physical properties of the support. In one embodiment, the amount of manganese present on the catalyst intermediate or catalyst is at least 20 ppmw, more preferably at least 60 ppmw, based on the weight of manganese. In some embodiments, the amount of manganese on the catalyst intermediate or catalyst is in the range of from 70 ppmw to 1000 ppmw, preferably from 80 ppmw to 500 ppmw, based on the weight of manganese. If too much manganese is present, catalyst performance such as stability, efficiency and/or activity may be impaired. If too little manganese is present, the effectiveness of the catalyst may also be impaired. A detailed study of the manganese concentration in the catalyst composition can be achieved by evaluating the effectiveness of the catalyst in determining the amount of manganese required. In some cases, it may be desirable to vary the amount of other components such as silver and other promoters to achieve an advantageous combination of effect and optimum catalyst performance.

Examples of the complexing agent in the first solution include ethylenediaminetetraacetic acid (EDTA); N,N'-ethylenediaminediacetic acid; N-hydroxyethylethylenediaminetriacetic acid; and diethylidenetriaminepentaacetic acid ( DTPA); nitrogen triacetic acid; 1,2-cyclohexyldiazepinetetraacetic acid (CDTA); N-hydroxyethyliminodiacetic acid; N-dihydroxyethylglycine and any derivative thereof. In one embodiment, the miscible is EDTA.

The amount of the cross-linking agent used varies widely, for example, depending on the particular compounding agent and the particular manganese component to be mismatched and the amount of the manganese component to be mismatched. Preferably, the amount of the cross-linking agent is at least 50%, more preferably at least 100%, of the amount required to form a complex with the manganese component in the first solution. For example, an excess of the amount of the complexing agent required to form the desired complex can be employed so that the complex can be maintained for a relatively long period of time. For example, the amount of the complexing agent included can be at least 150% or at least 200% or at least 400% or more of the amount required to form the desired complex.

In the step (i), the manganese component solution and the wrong agent solution may be combined simultaneously or sequentially to form a first solution. In one embodiment, the solution of the wrong agent is combined with an aqueous solution containing the manganese component. In another embodiment, the manganese component is in solid form and can be added to the tetherer solution. Additionally, heating may be required to dissolve the miscible, manganese component, or both. The pH of the first solution is less than or equal to 7 at any time during or after the preparation of the first solution. The pH of the first solution can be measured using a conventional pH meter or using a pH test paper. In one embodiment, the pH of the first solution is less than or equal to 7 after the manganese component is combined with the complexing agent or during the preparation of the first solution. In another embodiment, after the first solution is prepared, it is stored at a pH of less than or equal to 7. It is believed that, without being bound by any theory, the manganese component may exhibit enhanced solubility in the first solution comprising the tweaking agent at a pH of less than or equal to 7. As is known to those skilled in the art, the pH of the first solution can be adjusted to a pH of less than or equal to 7 by using an acid if necessary. Examples of suitable acids include acetic acid and formic acid and other acids which do not leave a residue after subsequent calcination of the impregnated support. In other embodiments, the pH of the first solution prepared according to the present invention may then be increased to above 7 by the addition of a basic compound such as an amine (e.g., monoethanolamine) prior to step (ii).

The first solution may additionally include one or more promoters other than manganese. In one embodiment, one or more other promoters do not comprise potassium.

In step (ii), a second solution comprising silver is combined with the first solution to form an impregnation solution. In one embodiment, the first solution has a pH of less than or equal to 7 when combined with the second solution. In another embodiment, the first solution has a pH greater than 7 when combined with the second solution. The second solution comprising silver includes a solvent or solubilizer of the silver-containing compound, such as the silver solution disclosed in the art. The particular silver compound employed may be selected, for example, from a silver complex, silver nitrate, silver oxide or silver carboxylate such as silver acetate, silver oxalate, silver citrate, silver phthalate, silver lactate, silver propionate, butyric acid. Silver and higher fatty acid silver salts. In one embodiment, the silver oxide compound that is mismatched with the amine is the preferred form of silver in the second solution.

A plurality of solvents or solubilizing agents may be employed to dissolve the silver compound in the second solution to the desired concentration. Solvents or solubilizers which are disclosed to be suitable for this purpose are lactic acid (U.S. Patent Nos. 2,477,436 and 3,501,417); ammonia (U.S. Patent No. 2,463,228); alcohols such as ethylene glycol (U.S. Patent Nos. 2,825,701 and 3,563,914). And an aqueous mixture of amines and amines (U.S. Patent Nos. 2,459,896; 3,563,914; 3,215,750; 3,702,259; 4,097,414; 4,374,260 and 4,321,206). In a preferred embodiment of the invention, the solubilizing agent is an amine/oxalate combination or an aqueous mixture of an amine and an oxalate, and the resulting impregnation solution has a pH greater than 7.

Silver oxide (Ag ₂ O) can be dissolved in a solution of oxalic acid and ethylenediamine to a level of about 30% by weight of silver. This solution was vacuum impregnated onto an alpha alumina support having a porosity of about 0.7 cc/g to produce a catalyst containing about 25% by weight silver based on the total weight of the catalyst.

In some embodiments, the catalyst intermediate or catalyst contains a high concentration of silver, typically at least 25% by weight or 30% by weight, more typically in the range of 25% by weight or 30% by weight to 60% by weight, based on the total weight of the catalyst. Therefore, in order to obtain a silver load of more than 25% by weight or 30 For weight percent and more than 30% by weight of the catalyst, it may be necessary to subject the carrier or catalyst intermediate to at least one or more sequential silver impregnations with or without a promoter until the desired amount of silver is deposited on the support. Physically, as will be described in detail.

In one embodiment, the silver particle size on the manganese-containing silver catalyst ranges from 10 angstroms to 10,000 angstroms in diameter. Preferably, the silver particle size is in the range of from greater than 100 angstroms to less than 5,000 angstroms. The silver needs to be relatively uniformly dispersed in the manganese-containing silver catalyst, in the entire manganese-containing silver catalyst, and/or on the manganese-containing silver catalyst.

The second solution may additionally include one or more promoters other than manganese, and such promoters may also be added after the first solution is combined with the second solution prior to impregnation of the carrier. Provide a booster of such accelerators. The term "promoting amount" as used herein refers to an amount by which a component of a catalyst acts effectively to provide one or more catalytic properties improvement over a catalyst that does not contain the component. Examples of catalytic properties include, inter alia, operability (anti-out of control), efficiency, activity, conversion, stability, and yield. Those skilled in the art will appreciate that one or more of the individual catalytic properties may be enhanced by "promoting amounts" which may or may not be enhanced or even likely to be reduced. It should be further understood that different catalytic properties can be enhanced under different operating conditions. For example, a catalyst with increased efficiency under a set of operating conditions can be operated under different sets of conditions that demonstrate activity rather than efficiency improvement.

The promotion provided by the promoter can be affected by many variables such as operating conditions, catalyst preparation techniques, surface area and pore structure of the support and surface chemistry, silver and other promoter content of the catalyst, other cations and anions on the catalyst. presence. The presence of other activators, stabilizers, promoters, enhancers or other catalyst modifiers can also affect the promotion. The particular form of promoter on the catalyst may not be known during the reaction to produce ethylene oxide, and the promoter may be present without the addition of relative ions during catalyst preparation. For example, a catalyst made with cesium hydroxide can be analyzed to contain hydrazine rather than hydroxide in the finished catalyst. Similarly, such as alkali metal oxides (e.g., cesium oxide) or transition metal oxides (e.g., MoO ₃₎ although the compound is not ionic, but may be used during or in preparation of the catalyst is converted to an ionic compound. For ease of understanding, the promoter will be referred to as a cation and an anion, regardless of the form in the catalyst under the operating conditions.

Examples of solid promoter compositions and features thereof, and methods of incorporating promoters as part of a catalyst are described in U.S. Patent No. 5,187,140, especially in columns 11 through 15; U.S. Patent Nos. 6,511,938, 5,102,848, 4,916,243 No. 4,908,343, 5,059,481, 4,761,394, 4,766,105, 4,808,738, 4,820,675, and 4,833,261.

Examples of well-known accelerators other than manganese for the catalyst for producing ethylene oxide include halides having an atomic number of 5 to 83 and elements other than oxygen in the groups 3b to 7b and 3a to 7a of the periodic table and / or oxygen anion. For some applications, one or more of the oxygen anions of nitrogen, sulfur, antimony, molybdenum, tungsten, and rhenium may be preferred. In some embodiments, the promoter comprises a compound of cerium, lanthanum, cerium, sulfur, molybdenum, and tungsten. In one embodiment, the one or more promoters are selected from the group consisting of Group IA metals, Group IIA metals, phosphorus, boron, sulfur, molybdenum, tungsten, chromium, titanium, cerium, zirconium, vanadium, niobium, tantalum, Barium, strontium, gallium, strontium and any mixtures thereof, and in another embodiment, potassium is excluded. In another embodiment, the one or more promoters comprise a Group IA metal selected from the group consisting of ruthenium, lithium, sodium, and any mixture thereof.

Types of anion promoters other than manganate suitable for use in the catalyst of the present invention include, by way of example only, oxyanions such as sulfate (SO ₄ ^-2 ), phosphate (e.g., PO ₄ ^-3 ), titanate (e.g. TiO ₃ ^-2 ), citrate (eg Ta ₂ O ₆ ^-2 ), molybdate (eg MoO ₄ ^-2 ), vanadate (eg V ₂ O ₄ ^-2 ), chromate (eg CrO ₄ ^-2 ), Zirconate (eg ZrO ₃ ^-2 ), polyphosphate, nitrate, chlorate, bromate, borate, citrate, carbonate, tungstate, thiosulfate, citrate and similar oxygen anions. Halogen ions may also be present, including fluoride ions, chloride ions, bromide ions, and iodide ions.

It is well recognized that many anions have complex chemical chemistry and can exist in one or more forms, such as orthovanadate and metavanadate; and various molybdate oxyanions such as MoO ₄ ^-2 and Mo ₇ O ₂₄ ^-6 and MO ₂ O ₇ ^-2 . The oxyanion may also include a mixed metal-containing oxyanion comprising a polyoxyanion structure. For example, manganese and molybdenum can form a mixed metal oxyanion. Similarly, other metals provided in an anionic, cationic, elemental or covalent form can enter the anionic structure.

Although an oxyanion or oxyanion precursor can be used in a solution for impregnating a support, the particular oxyanion or precursor initially present may be converted to another form under catalyst preparation conditions and/or during use. . In fact, the elements can be converted to a cationic or covalent form. In many cases, analytical techniques may not be sufficient to accurately identify the substance present. The present invention is not intended to be limited by the exact materials that may ultimately be present on the catalyst during use.

The amount of the anion promoter other than manganate may vary widely, for example from 0.0005 wt% to 2 wt%, preferably from 0.001 wt% to 0.5 wt%, based on the total weight of the catalyst.

The catalyst prepared using the specific examples of the present invention may comprise a ruthenium promoter. Various forms of oxime promoters may be provided, for example in the form of a metal, covalent compound, cation or anion.铼 Promoted supported silver-containing catalysts are known from U.S. Patent No. 4,761,394 and U.S. Patent No. 4,766,105. On the support material, the catalyst comprises silver, ruthenium or a compound thereof, and in some In a bulk embodiment, a second promoter, such as another metal or compound thereof, and optionally a third promoter, such as one or more of sulfur, phosphorus, boron, and a compound thereof, are included.

The hydrazine material which enhances the efficiency and/or activity is not determined and may be a component which is added or which is produced during the preparation of the catalyst or during use as a catalyst. Examples of the ruthenium compound include, for example, ruthenium halide, ruthenium salt of ruthenium oxyhalide, ruthenate, perrhenate, ruthenium oxide, and acid. However, it is also preferred to use alkali metal perrhenate, ammonium perrhenate, alkaline earth metal perrhenate, silver perrhenate, other perrhenates, and antimony pentoxide. The ruthenium pentoxide Re ₂ O ₇ is hydrolyzed to perrhenic acid HReO ₄ or perhydro phthalate when dissolved in water. Therefore, for the purposes of this specification, antimony pentoxide can be considered as perrhenate, ie ReO ₄ . Other metals such as molybdenum and tungsten may exhibit similar chemical properties.

When used, the rhodium component is typically provided in an amount of at least 1 ppmw, such as at least 5 ppmw, such as from 10 ppmw to 2000 ppmw, typically between 20 ppmw and 1000 ppmw, based on the weight of the total weight of the catalyst.

In some cases, one or more promoters other than manganese comprise a mixture of, for example, ruthenium and at least one other alkali metal cation to achieve synergistic efficiency enhancement, as disclosed in U.S. Patent No. 4,916,243. In some embodiments of the invention, potassium is not one of the alkali metal promoters.

The concentration of the alkali metal promoter in the finished catalyst is not narrow and can vary over a wide range. The optimum alkali metal promoter concentration for a particular catalyst will depend on the performance characteristics, such as catalyst efficiency, catalyst aging rate, and reaction temperature.

The concentration of the alkali metal in the finished catalyst (for example, by weight of the cation of cerium) may vary from 0.0005 wt% to 1.0 wt%, preferably from 0.005 wt% to 0.5 wt%. Deposited or present on the support or catalyst table based on the weight of the cation calculated based on the total supported material The preferred amount of cations on the face is generally between 10 ppm and 4000 ppm, preferably between 15 ppm and 3000 ppm, and more preferably between 20 ppm and 2500 ppm. The amount between 50 ppm and 2000 ppm is often optimal. When an alkali metal ruthenium is used in combination with other cations, the ratio of ruthenium to any other alkali metal and alkaline earth metal salt (if used) to achieve the desired performance is not narrow and can vary over a wide range. The ratio of cerium to other cation promoters can vary from 0.0001:1 to 10,000:1, preferably from 0.001:1 to 1,000:1.

In step (iii), the carrier or the impregnated carrier is impregnated with at least a portion of the impregnation solution to form a catalyst intermediate. According to a preferred embodiment of the invention, the pH of the impregnation solution used to impregnate the support is greater than 7. Suitable support materials for the catalyst intermediate can include a porous refractory support or material that is relatively inert in the presence of the reaction mixture and the product epoxide for epoxidation and that can withstand the preparation conditions upon conversion to a catalyst. For example, the carrier can comprise alpha-alumina, tantalum carbide, ceria, zirconia, magnesia, pumice, zeolite, charcoal, various clays, alkaline earth metal carbonates such as calcium carbonate, and mixtures thereof. In one embodiment, the carrier comprises alpha-alumina.

There are many well known methods for preparing support suitable for use in alkylene oxide catalysts. Some of these methods are described, for example, in U.S. Patent Nos. 4,379,134, 4,806,518, 5,063,195, 5,384,302, 6,831,037, and the like. For example, an alpha-alumina carrier having a purity of at least 95% can be prepared by compounding (mixing), extruding, drying, and calcining the raw materials. In this case, the starting raw material usually comprises one or more α-alumina powders having different characteristics, a clay-type material which can be added as a binder to provide physical strength, and a mixed use to provide after removal during the calcination step. A burnout material (usually an organic compound) of the desired porosity and/or pore size distribution. The content of impurities in the finished carrier is determined by the raw materials used. The purity and its degree of volatilization during the calcination step are determined. Common impurities may include cerium oxide, alkali metal oxides and alkaline earth metal oxides, as well as trace metals and/or non-metal additives. Another method of preparing a support having properties particularly suitable for use in an alkylene oxide catalyst comprises mixing zirconium silicate with aluminate alumina (AlOOH) and/or gamma alumina, optionally with an acidic component. And a mixture of a halogen anion (preferably a fluoride anion) is peptized to obtain a peptized halogenated alumina, and the peptized halogenated alumina is shaped (for example, by extrusion or pressing) to obtain a shaped peptized halogenated product. Alumina, dried shaped peptized halogenated alumina to obtain dried shaped alumina, and calcined dried shaped alumina to obtain pellets of the modified alpha-alumina support.

A very high purity alumina, i.e. at least 98% by weight of alpha-alumina, any remaining components being cerium oxide, an alkali metal oxide (such as sodium oxide) and traces of other metals and/or non-metals have been employed. Additives or impurities. Similarly, alumina of lower purity, that is, 80% by weight of α-alumina, and the remainder of one or more amorphous and/or crystalline alumina and other alumina, ceria, cerium oxide-alumina have been used. , mullite, various alkali metal oxides (such as potassium oxide and cerium oxide), alkaline earth metal oxides, transition metal oxides (such as iron oxide and titanium oxide), and other metal oxides and non-metal oxides Things. Additionally, the materials used to prepare the support may comprise compounds known to improve catalyst performance, such as ruthenium (such as ruthenate) and molybdenum.

In one embodiment, the support material comprises at least 80% by weight of alpha-alumina and comprises less than 30 ppmw of acid leachable alkali metal, the weight percent of alpha-alumina and the concentration of acid leachable alkali metal based on the weight of the carrier, The acid leaching alkali metal is selected from the group consisting of lithium, sodium, potassium, and mixtures thereof.

The pore volume of the α-alumina carrier is preferably at least 0.3 cubic centimeters per gram (cm ³ /g) and more preferably from 0.4 cm ³ /g to 2.0 cm ³ /g; and the median pore diameter is from 1 to 50 Micron.

The alpha-alumina support preferably has a specific surface area of at least 0.5 square meters per gram (m ² /g) and more preferably at least 0.7 m ² /g. The surface area is typically less than 10 m ² /g and preferably less than 5 m ² /g.

In one embodiment, the alpha-alumina support comprises particles each having at least one substantially planar major surface having a layered or sheet-like morphology close to the shape of a hexagonal plate (some particles have two or more particles) Flat surface), at least 50% (by number) of particles have a major dimension of less than 50 microns.

The alpha-alumina carrier can have any suitable shape. Exemplary shapes of the carrier include pellets, chunks, tablets, fragments, pellets, rings, spheres, wheels, inner surfaces, and/or outer rings having a star-shaped ring shape and the like. The carrier can have any size suitable for use in the reactor. For example, a parallel elongated tube having a plurality of catalysts having an outer diameter of 1 吋 to 3 吋 (2.5 cm to 7.5 cm) and a length of 15 呎 to 45 呎 (4.5 m to 13.5 m) (in a suitable shell) In a fixed bed ethylene oxide reactor in the body, a circular shape (such as a sphere, a pellet, a ring, a cross-divided ring, a five-ring, a small piece) having a diameter of 0.1 吋 (0.25 cm) to 0.8 吋 (2 cm) is required. And similar shapes) alpha alumina support.

The carrier or the impregnated carrier is impregnated with at least a portion of the impregnation solution to form a catalyst intermediate. The impregnation of a similar carrier is provided in U.S. Patent Nos. 6,511,938 and 5,187,140. After impregnation, the catalyst intermediate is separated from any remaining unabsorbed impregnation solution. This is preferably accomplished by drawing up an excess impregnation solution or by using another separation technique such as filtration or centrifugation.

After the impregnation step (iii), calcination or other procedures may be performed after separating the unabsorbed impregnation solution to promote silver insolubility. In general, the catalyst intermediate is hot during the calcination process. Treatment to effect decomposition and reduction of the catalytic material, such as a silver metal compound (in most cases a complex), into a metal form and depositing manganese and any other promoter. The calcination can be carried out at a temperature of from 100 ° C to 900 ° C, preferably from 200 ° C to 700 ° C, for a period of time sufficient to, for example, substantially convert any salt (eg, a silver salt) to a metal (eg, silver metal).

Although a wide range of heating periods have been proposed in the art to heat treat the impregnated carrier (e.g., U.S. Patent No. 3,563,914, the disclosure of which is incorporated herein by reference to the entire disclosure of the entire disclosure of the entire disclosure of the entire disclosure of the disclosure of the present disclosure of No. discloses heating at a temperature of 100 ° C to 375 ° C for 2 to 8 hours to reduce the silver salt in the catalyst), but the only important thing is that the reduction time is temperature dependent, thereby achieving, for example, the substantially complete reduction of the silver salt to the metal. To achieve this, a continuous or stepwise heating program is required. It is preferred to continuously calcine the catalyst intermediate for a relatively short period of time (such as no longer than 1 hour) and to effectively produce the catalyst of the present invention. When the calcination is carried out once or more, the calcination conditions of the respective calcinations are not necessarily the same.

The heat treatment is preferably carried out in air, but nitrogen, hydrogen, carbon dioxide or other atmosphere may also be employed. The equipment used for this heat treatment can use the static or flowing atmosphere of the gases to achieve reduction, but with a better flow atmosphere. In some embodiments, the catalyst intermediate can be chemically treated to reduce any silver compound to metallic silver.

In one embodiment, a method of making a manganese-supported silver catalyst includes following steps (i) through (iii) to form a catalyst intermediate, which is then calcined or chemically treated to form a manganese-containing silver catalyst. In some embodiments, two or more impregnation steps are used to produce a manganese-supported silver catalyst. For example, in sequential impregnation, by following steps (i) to (iii), impregnation with at least a portion of the first impregnation solution containing silver, manganese, and optionally one or more promoters other than manganese Hold to form a first catalyst intermediate. Then roast or chemical treatment A catalyst intermediate to form a second catalyst intermediate. For subsequent impregnation, the second catalyst intermediate is impregnated with at least a portion of the second impregnation solution by following steps (i) through (iii) or by any known impregnation process. In another embodiment, the carrier is impregnated with at least a portion of the first impregnation solution containing silver to form a first impregnated support. The first impregnated support is fired to form a silver impregnated support. The silver impregnated support is subjected to a second impregnation step following steps (i) to (iii) to form a first catalyst intermediate.

In a specific example of sequential impregnation, the concentration of silver in the second impregnation solution may be higher than the first impregnation solution. For example, if 30% of the total silver concentration is required in the catalyst, 10% by weight of a small amount of silver is deposited on the carrier as a result of the first impregnation, followed by a second silver impregnation on the carrier. The remaining 20% by weight was deposited and all percentages were calculated based on the finished catalyst. In other embodiments, substantially equal amounts of silver are deposited during each impregnation step. Generally, to achieve equivalent deposition in each impregnation step, the silver concentration in the subsequent impregnation solution may need to be higher than the initial impregnation solution. In other embodiments, a higher amount of silver is deposited on the carrier during the initial impregnation than the silver deposited in the subsequent impregnation. Impregnation of the catalyst support can be accomplished using one or more solutions containing silver and a promoter according to well known procedures for simultaneous or sequential deposition. For simultaneous deposition, after impregnation, heat treatment or chemical treatment is performed by impregnating the support to reduce the silver compound to silver metal and deposit the salt on the catalyst surface.

The manganese-supported silver catalyst of the present invention is particularly useful for continuously producing ethylene oxide by contacting ethylene with oxygen or an oxygen-containing gas in a gas phase process in a gas phase process. The epoxidation reaction can be based on air or based on oxygen, see Kirk-Othmer's Encyclopedia of Chemical Technology, 3rd Edition, Vol. 9, 1980, pages 445 to 447. The process of industrial implementation depends on the required quality speed and productivity, from 200 ° C to 300 ° C and can be 5 large The feed stream containing ethylene and oxygen is continuously introduced into the reactor containing the manganese-supported silver catalyst at a pressure varying between 30 atmospheres. The residence time in large scale reactors is typically from about 0.1 second to 5 seconds. The feed stream can also include gas phase regulators such as organic chlorides, ethane, carbon dioxide, and water.

The process may be provided with oxygen in the form of pure molecular oxygen or in the form of an oxygen-containing gas, wherein the gas may additionally contain one or more gaseous components that are substantially inert to the oxidation process, such as gaseous diluents such as nitrogen, helium. , methane and argon. The crude ethylene feed stream may also contain other hydrocarbons, such as ethane, in the form of impurities. Ethane may also be added to the industrial reactor to better control the inhibition of the organic chloride. The relative volume ratio of ethylene to oxygen in the reaction mixture can be determined according to any of these known conventional values.

Gas phase regulators are also commonly referred to as inhibitors and/or enhancers. Suitable gas phase regulators may be selected from the group consisting of C1-C8 chlorinated hydrocarbons. The ability of a gas phase regulator to enhance the efficiency and/or activity of an epoxidation process depends on the degree to which the surface of the catalyst is chlorinated, for example, by depositing a specific chlorine species such as atomic chlorine or chloride ions on the catalyst. . However, hydrocarbons lacking chlorine atoms will strip the chloride from the catalyst and thus reduce the overall efficiency gain provided by the gaseous chlorine-containing promoter material. A discussion of this phenomenon can be found in Berty, "Inhibitor Action of Chlorinated Hydrocarbons in the Oxidation of Ethylene to Ethylene Oxide", Chemical Engineering Communications, Vol. 82 (1989) pp. 229-232 and Berty, "Ethylene Oxide Synthesis", Applied Industrial. Catalysis, Vol. I (1983), pp. 207-238. Salty paraffinic compounds such as ethane or propane are particularly effective at stripping chloride from the catalyst. However, olefins such as ethylene and propylene are also used to strip chlorides from the catalyst. Some of these hydrocarbons may also be introduced as impurities into the ethylene feed or may be for other reasons (such as use) The recycle stream) is present in the feed stream.

Carbon dioxide is generally considered an inhibitor, and the inhibition of process efficiency by carbon dioxide can vary with its concentration. Different types of accelerators may be more desirable in certain industrial processes for the different types of accelerators used in the preparation of the catalysts of the present invention. Typically, the amount of carbon dioxide used in an industrial process can vary from less than 2 mole percent to 15 mole percent to achieve optimum results under both air processing conditions and oxygen processing conditions. The amount of carbon dioxide can also depend on the size and type of carbon dioxide scrubbing system used.

Typically, the volume ratio of olefin to oxygen in the reaction mixture can vary from 1/1 to 10/1. Likewise, the amount of inert gas, diluent or other gaseous components such as water, carbon dioxide, gas phase modifiers, and gaseous byproduct inhibitors can vary depending on the known ranges of knowledge seen in such techniques.

Suitable reactors for the epoxidation reaction include fixed bed reactors, fixed bed tubular reactors, continuous stirred tank reactors (CSTR), fluidized bed reactors, and various reactors well known to those skilled in the art. The reaction conditions for carrying out the epoxidation reaction are well known and widely described in the prior art. This applies to the following reaction conditions: such as temperature, pressure, residence time, reactant concentration, gas phase diluents (e.g., nitrogen, methane, and carbon dioxide), gas phase inhibitors (e.g., organic chlorides), and the like. The desirability of recirculating unreacted feeds using a reactor arranged in series, or using a single pass system, or using a continuous reaction to increase ethylene conversion, can be readily determined by those skilled in the art. The particular mode of operation selected will usually be determined by process economics. Ethylene oxide produced according to a specific example of the present invention is separated and recovered from the reaction product by a conventional method.

The ethylene oxide produced by the epoxidation process of the present invention is typically processed to provide other downstream products such as ethylene glycol, glycol ethers, ethyl acetate and ethanolamine. Epoxy B Conversion of the alkane to ethylene glycol or glycol ether can comprise, for example, reacting the desired ethylene oxide with water in the presence of an acidic or basic catalyst. For example, in order to prioritize the production of ethylene glycol over the glycol ether, it may be, for example, in the presence of a 0.5% to 1.0% by weight sulfuric acid catalyst based on the total reaction mixture, at 50 ° C to 70 ° C, at 1 Performing a liquid phase reaction under absolute pressure, or performing a gas phase reaction at 130 ° C to 240 ° C and an absolute pressure of 20 to 40 bar, preferably in the absence of a catalyst, to cause an excess of ethylene oxide and ten times the molar excess. The water reacts. If the proportion of water is reduced, the proportion of glycol ether in the reaction mixture will increase. Alternatively, the glycol ether can be prepared by converting ethylene oxide with an alcohol such as methanol or ethanol or by replacing at least a portion of the water with an alcohol. The resulting ethylene glycol and glycol ethers can be used in a variety of end applications in food, beverage, tobacco, cosmetics, thermoplastic polymers, curable resin systems, detergents, heat transfer systems, and the like.

Conversion of the ethylene oxide produced by the process of the invention to ethanolamine can comprise, for example, reacting ethylene oxide with ammonia. Anhydrous ammonia or ammonia water can be used. The resulting ethanolamine can be used, for example, in the treatment of natural gas. Ethylene oxide can be converted to the corresponding ethyl carbonate by reacting ethylene oxide with carbon dioxide. If necessary, ethylene glycol can be prepared by subsequently reacting ethyl carbonate with water or an alcohol to form ethylene glycol. For a suitable method, reference is made to U.S. Patent No. 6,080,897.

Ethylene glycol is used in two major applications: as a raw material for poly(ethylene terephthalate) for use in polyester fibers, films and containers, and as an antifreeze for automobiles. Diethylene glycol, triethylene glycol and tetraethylene glycol are by-products of ethylene glycol.

Example

Preparation of a silver oxalate solution: An amine solution was prepared by mixing 11.47 parts by weight of ethylenediamine (high purity grade) with 20.00 parts by weight of distilled water. Next, 11.60 parts by weight of oxalic acid dihydrate (reagent grade) was slowly added to the amine solution under ambient conditions. The rate of addition of oxalic acid dihydrate makes The exotherm does not cause the temperature of the oxalate solution to rise above 40 °C. Next, 19.82 parts by weight of silver oxide was added, followed by 4.01 parts by weight of monoethanolamine (without Fe and Cl). Next, distilled water was added to adjust the weight of the solution to 70.00 parts by weight to form a silver oxalate solution. The pH of the silver oxalate solution is in the range between 11 and 12.

Study on Stability of Manganese in Solution

Comparative Example 1

Solution A for preparing stability study of manganese in solution: About 0.293 g of an aqueous solution of manganese (II) nitrate (0.157 g of Mn per 1 g of solution) was added to 588.3 g of the above silver oxalate solution. Next, an aqueous solution containing a promoter (without Mn) compound (total of about 16.14 g) was added, followed by stirring at 20 ° C for 30 minutes to obtain a solution A. A sample of solution A was withdrawn and filtered through 0.1 μ filter paper, and the concentration of manganese in the filtrate was analyzed by X-ray fluorescence (XRF). The XRF analysis error is typically about ±3 ppm and the results are provided in Table 1. In the table, the calculation of Mn (manganese) refers to the stoichiometric amount of manganese in the solution. XRF Mn is the amount of manganese remaining in the filtered solution as measured by XRF. The XRF Mn value was about 60.9 ± 3 ppm, indicating that manganese precipitated from solution A.

Comparative Example 2

Solution B for the stability study of manganese in solution: about 1.0724 grams An aqueous solution of diammonium ethylenediaminetetraacetate (46 wt% EDTA) was added to the solution A and stirred at 20 ° C for 30 minutes to obtain a solution B. A sample of solution B was withdrawn for XRF analysis and analyzed according to the methods previously described. As shown in Table 1, the XRF value of Solution B was about 54.6 ± 3 ppm, indicating that the manganese precipitate was higher compared to Solution A.

Example 1

Preparation of Solution C for Stability Study of Manganese in Solution: The experiment of Comparative Example 2 was repeated, except that about 0.293 g of an aqueous solution of manganese (II) nitrate was added (0.157 per 1 g of solution) before being added to the silver oxalate solution. The gram of Mn) is combined with about 1.072 grams of an aqueous solution of diammonium ethylenediaminetetraacetate (46 wt% EDTA) and thoroughly mixed to form a first solution. The pH of the first solution thus prepared is less than or equal to 7. The first solution was then added to the silver oxalate solution, followed by the addition of other (Mn-free) accelerator solution and stirring at 20 ° C for 30 minutes to obtain solution C. The pH of solution C is greater than 7. Solution C showed an XRF Mn value of about 80.0 ± 3 ppm, which matched the calculated Mn value, indicating that the manganese precipitated from the solution was the least.

Study on the variability of manganese content in batches of impregnation solution

Comparative Example 3

Preparation of catalyst batches according to prior art methods

Preparation of the first impregnated carrier: vacuum impregnation with a first silver impregnation solution typically containing 31% by weight of silver oxide, 18% by weight of oxalic acid, 18% by weight of ethylenediamine, 6% by weight of monoethanolamine and 27% by weight of distilled water - Alumina carrier. The first silver impregnation solution was prepared by mixing 1.14 parts of ethylenediamine (high purity grade) with 1.75 parts of distilled water to form an aqueous solution of ethylenediamine. Thereafter, 1.16 parts of oxalic acid dihydrate (reagent grade) was slowly added to the ethylenediamine solution so that the temperature of the solution did not exceed 40 ° C, followed by the addition of 1.98 parts of silver oxide and 0.40 parts of monoethanolamine (without Fe and Cl). A first silver impregnation solution is formed. The pH of the first silver impregnation solution is in the range between 11 and 12.

The α-alumina carrier is impregnated with the first silver impregnation solution. The carrier is kept immersed in the first silver impregnation solution for 5 to 30 minutes under ambient conditions. The impregnated support is then removed and the excess solution is then withdrawn for 10 to 30 minutes.

The impregnated support is then calcined to effect reduction of silver on the surface of the support to form a first impregnated support. For calcination, the impregnated support was spread in a single layer on a stainless steel wire mesh carrier, placed on a conveyor belt and conveyed to a heated zone for 2.5 minutes. The heated zone was maintained at 500 ° C by passing hot air up through the conveyor belt and through the impregnated carrier. After firing in the heated zone, the first impregnated carrier is maintained in the open air and allowed to reach room temperature and weighed. A first catalyst intermediate is prepared: the first impregnated support is vacuum impregnated with a second silver impregnation solution to form a first catalyst intermediate. The second silver impregnation solution comprises a solution derived from the previous silver impregnation solution and a fresh aliquot of each of the manganese nitrate and diammonium ethylenediaminetetraacetate added directly to the silver oxalate solution. The second impregnation solution includes one or more promoters selected from the group consisting of ruthenium, lithium, sodium, and any mixture thereof. After impregnation, excess solution is withdrawn from the first catalyst intermediate and calcined as previously described for the first impregnated support to form a first catalyst. The weight percentage of silver is calculated based on the weight of the first catalyst and the carrier. The concentration of the promoter is calculated assuming that the deposition rate of the promoter is similar to silver. As described in the previous study regarding the stability of manganese in solution, the manganese content of the first catalyst can be correlated to the manganese content of the impregnation solution and determined using XRF. A variety of first catalyst batches having a wide range of desired target levels and various scaled scales are prepared following this method. A wide range of desired target levels can be obtained by varying the stoichiometric amount of the impregnation solution. Figure 1 is a graph of variability in the amount of manganese as determined by XRF analysis in a batch of silver impregnation solution prepared for the preparation of a first catalyst batch, and is expressed as a percentage change in manganese content relative to a desired target content. This example shows that the large amount of manganese in the impregnation solution relative to the target value is in the range of about +20% to about -90%. Catalysts prepared using such impregnation solutions are also expected to reflect this variability in manganese.

Example 2

Preparation of catalyst batches according to the process of the invention

A second catalyst intermediate was prepared according to the process of the invention: a first impregnated support was prepared according to the method of Comparative Example 3, followed by vacuum impregnation with a third silver impregnation solution to form a second catalyst intermediate. The third silver impregnation solution comprises a solution drawn from the previous silver impregnation solution and a fresh aliquot of each of the first solution and the second solution. The first solution comprises manganese (II) nitrate and diammonium ethylenediaminetetraacetate and has a pH of less than or equal to 7 at any time during or after preparation of the first solution, that is, at least one time point. The second solution comprises a solution of silver oxalate. The third silver impregnation solution includes one or more promoters selected from the group consisting of ruthenium, lithium, sodium, and any mixture thereof. The pH of the third silver impregnation solution is greater than 7. After impregnation, excess solution is withdrawn from the second catalyst intermediate and calcined as previously described for the first impregnated support to form a second catalyst. Calculate the weight percentage of silver and the concentration of the accelerator. The manganese content of the second catalyst can be correlated to the manganese content of the third silver impregnation solution and measured using XRF. Various second catalyst batches having a wide range of desired target levels and various scaled scales are prepared. 2 is a graph showing the variability of the amount of manganese as determined by XRF in the batch of the impregnation solution prepared according to the present invention for preparing the second catalyst batch, and expressed as a percentage change of the manganese content relative to the desired target content. . The Mn concentration is within ±10% relative to the target. This example demonstrates that the process of the invention wherein the first solution is formed by combining manganese nitrate with diammonium ethylenediaminetetraacetate prior to addition to the second solution comprising silver reduces the variability in the amount of manganese in the resulting impregnation solution. Catalysts prepared using such impregnation solutions are also expected to reflect this lower variability.

Comparative Example 4

The manganese-containing first catalyst batches 4-1 to 4-5 were generally prepared on a large scale according to the procedure as described in Comparative Example 3. The concentration of manganese in the first catalyst batches 4-1 to 4-5 was determined using XRF and is provided in Table 2.

Catalyst Efficacy Study: A plurality of 80 cc samples were withdrawn from each of the first catalyst batches and evaluated in a backmixed (CSTR) Berty-type autoclave reactor under the following conditions: inlet concentration of 8.0 vol% oxygen, 6.5 vol% carbon dioxide, 30.0 vol% ethylene, 0.50 vol% ethane, 3.5 ppmv ethyl chloride, the balance being nitrogen; the pressure was 1900 kPa gauge; the total flow rate was 640 standard liters/hour (measured by nitrogen); and the startup temperature was 230 °C. After startup, the temperature was adjusted to give an outlet concentration of 2.0 vol% ethylene oxide. For each batch, the average autoclave temperature required to obtain an outlet concentration of 2.0 vol% ethylene oxide after seven days of testing is shown in Table 2.

Example 3

This example illustrates the performance improvement of a manganese-containing silver catalyst prepared using the process of the present invention.

Large-scale preparation of manganese-containing second reminders according to the procedure outlined in Example 2 Batches 3-1 to 3-6. The concentration of manganese in the second catalyst batches 3-1 to 3-6 was determined using XRF and is provided in Table 3. The second catalyst batches 3-1 to 3-6 were evaluated following the procedure of the catalyst performance study provided in Comparative Example 4. The manganese concentration and temperature of the second catalyst batch, which is the average autoclave temperature required to obtain an outlet concentration of 2.0 vol% ethylene oxide after seven days of testing, are shown in Table 3.

Figure 3 is a comparison of the activity of the second catalyst batch of Example 3 with the first catalyst batch of Comparative Example 4. The temperature required to produce 2.0 vol% ethylene oxide for the second catalyst batch of Example 3 was significantly lower, indicating that the catalyst activity was improved compared to the first catalyst batch of Comparative Example 4. Advantageously, the improvement in catalyst activity may also be beneficial to the life of the second catalyst batch of Example 3.

Comparative Example 5

This example focuses on the variability of the manganese content during the preparation of the large scale first catalyst batch (4-1 to 4-5) as described in Comparative Example 4. Figure 4 is a graph of the normalized manganese content of the batch of manganese-containing oxalic acid amine solution (labeled 5*) prepared for preparing the first catalyst batches 4-1 to 4-5, wherein the normalized manganese content is a solution The amount of manganese measured in the batch (eg XRF) The ratio of the analyzed) to the target manganese content divided by the average of the ratios in all solution batches. The plurality of points on the graph of Figure 4 thus correspond to each of the large scale first catalyst batches of Comparative Example 4 and are indicated even in the preparation of the manganese-containing silver catalyst according to the prior art process, even within each of the first catalyst batches. The change in manganese content between the solution batch and the solution batch.

Example 4

This example illustrates the benefits of the process of the invention observed during the preparation of large scale second catalyst batches (3-1 to 3-6) as described in Example 3. Figure 4 is a graph of normalized manganese content of a batch of Mn-containing oxalic acid amine solution (labeled 4) prepared in accordance with the process of the present invention during the preparation of second catalyst batches 3-1 to 3-5, wherein normalization The manganese content is the ratio of the manganese content measured in the solution batch (as analyzed by XRF) to the target manganese content divided by the average of the ratios in all solution batches. The plurality of points on the graph of Figure 4 thus correspond to each of the large scale second catalyst batches of Example 3. The solution batch prepared using the method of the present invention showed a lower variability in the amount of manganese between the batch and the batch than the batch of Mn-containing oxalic acid amine solution prepared by the prior art method (labeled as 5*).

Claims (10)

A method of producing a manganese-supported silver catalyst intermediate comprising the steps of: (i) preparing a first solution comprising a manganese component and a complexing agent, wherein at any time during or after step (i) a solution having a pH of less than or equal to 7; (ii) combining the first solution with a second solution comprising silver to form an impregnation solution; and (iii) impregnating the support with at least a portion of the impregnation solution to form the catalyst intermediate Wherein the pH of the impregnation solution is greater than 7. The method of claim 1, wherein the manganese component comprises manganese acetate, manganese ammonium sulfate, manganese citrate, manganese disulfate, manganese oxalate, manganese manganese nitrate, manganese sulfate, permanganate anion, manganate One or more of anions and any combination thereof. The method of claim 1 or 2, wherein the complexing agent is selected from the group consisting of ethylenediaminetetraacetic acid, N,N'-ethylenediaminediacetic acid, and N-hydroxyethylethylenediamine. Triacetic acid, di-extended ethyltriamine pentaacetic acid, nitrogen triacetic acid, 1,2-extended cyclohexyldiazide tetraacetic acid; N-hydroxyethyliminodiacetic acid, N-dihydroxyethylglycine And any of its derivatives. The method of any one of claims 1 to 3, wherein the wrong agent is ethylenediaminetetraacetic acid. The method of any one of clauses 1 to 4, wherein the first solution or the second solution or both additionally comprise one or more promoters other than the manganese component. The method of claim 1, wherein the manganese-supported silver catalyst intermediate prepared by the method of any one of claims 1 to 11 The variability is less than the variability in the amount of manganese on the manganese-containing supported silver catalyst intermediate prepared by a process that does not include the preparation of the first component comprising the manganese component and the complexing agent. The method of any one of clauses 1 to 6, wherein the manganese is present in the manganese-supported silver catalyst intermediate in an amount of at least 20 ppmw. The method of any one of claims 1 to 7, wherein manganese is present in the manganese-supported silver catalyst intermediate in an amount of from 20 ppmw to 1000 ppmw. A gas phase process for continuously producing ethylene oxide, comprising manganese-containing supported particles prepared by carrying a manganese-supported silver catalyst intermediate according to any one of claims 1 to 8 In the presence of a silver catalyst, ethylene is contacted with oxygen or an oxygen-containing gas in the gas phase, and the contacting is carried out under processing conditions sufficient to produce the ethylene oxide. The method of claim 9, further comprising converting the ethylene oxide to one or more of ethyl carbonate, ethylene glycol, ethanolamine or glycol ether.