Alkylene oxide catalyst that can be manufactured rapidly in one step

Abstract

A supported silver catalyst and use thereof in a process for producing an olefin oxide, such as ethylene oxide, by the direct oxidation of an alkylene with oxygen or an oxygen-containing gas, wherein the catalyst provides good catalyst activity and / or efficiency despite loading levels of silver in the range of

Description

[Technical Field]

[0001] This invention relates to a supported silver catalyst, its manufacture, and its use in the direct production of alkylene oxides (particularly ethylene oxide) from oxygen and olefins (such as ethylene). [Previous Technology]

[0002] Epoxy compounds are known to have multiple uses. For example, ethylene oxide, used to produce ethylene glycol, is used in the preparation of polyester fibers and resins, nonionic surfactants, glycol ethers, ethanolamines, and polyethylene polyether polyols. Propylene oxide, used to produce propylene glycol and polypropylene polyether polyols, is used in polyurethane polymer applications.

[0003] The direct reaction of ethylene with oxygen or oxygen-containing gases in the presence of a silver catalyst is a well-established and mature technique. An overview of the history of direct ethylene oxidation can be found in US 4,916,243. This patent describes more specifically a catalyst comprising silver deposited on a macroporous alumina support, further comprising cesium and at least one other alkali metal selected from lithium, sodium, potassium, and rubidium, such that the combination of cesium and other alkali metals has a synergistic promoting effect on the oxidation process.

[0004] Supported silver catalysts used for the production of epoxides should possess acceptable activity, efficiency, and stability. The "activity" of a catalyst can be quantified in several ways, one being the mole percentage of epoxide in the reactor effluent relative to that in the influent (the mole percentage of epoxide in the influent is generally, but not necessarily, close to zero percent), while the reactor temperature remains substantially constant; and another being the temperature required to maintain a given rate of epoxide production. In many cases, activity is measured over a period of time in terms of the mole percentage of epoxide produced at a specific isothermal temperature. Alternatively, activity can be measured based on the temperature required to maintain a specific constant mole percentage of epoxide, such as ethylene oxide. The "efficiency" of oxidation, synonymous with "selectivity," refers to the total amount, in mole percentage, of converted or reacted olefins that form a particular product. For example, "selectivity for epoxides" refers to the mole percentage of converted or reacted olefins that form epoxides. One measure of a catalyst's useful lifetime is the length of time reactants can pass through the reaction system, taking into account all relevant factors to achieve acceptable production levels during this period. As used herein, "deactivation" refers to the permanent loss of activity and / or efficiency, i.e., an irreversible reduction in activity and / or efficiency. Generally, deactivation tends to occur more rapidly at higher reactor temperatures. The "stability" of a catalyst is inversely proportional to the rate of deactivation. Lower deactivation rates are generally desirable.

[0005] In recent years, improvements in the activity, efficiency, and stability of alkylene oxide catalysts have been achieved through the use of modified alumina supports, preferably derived from high-purity α-alumina with a composition purity greater than 95% by weight. For example, WO-A1-2005 / 023417 discloses the modification of high-purity, high-performance α-alumina supports by impregnating the support with an alkali metal hydroxide (such as sodium hydroxide), followed by washing the support to remove unbound or excess alkali. Subsequently, the modified support is impregnated with silver and cesium, and optionally with additional promoters such as rhenium, manganese, and / or other alkali metals. Similarly, WO-A1-2005 / 039757 discloses a high-purity α-alumina support containing zircon, followed by impregnation of zircon-modified alumina with silver and one or more promoting cations or anions. The carriers and catalysts derived from these improved processes generally do not contain binders, such as clay. Binders often introduce excess metals that are not needed, so it is ideal to avoid using binders.

[0006] Other references such as WO-A1-2007 / 123932, high-efficiency catalysts improved for better performance under reactor disturbance conditions.

[0007] The catalysts reported in these studies generally rely on relatively high silver loadings, typically greater than 30% by weight or even 35% by weight. To achieve such high silver content, the manufacturing process generally requires multiple impregnation steps, which increases the cost of catalyst production and reduces the annual capacity of the catalyst manufacturing plant. Furthermore, especially in larger ethylene oxide production plants, the total amount of silver required can represent a significant capital requirement, particularly considering the rising price of silver. Therefore, there is a demand for highly efficient silver catalysts for producing ethylene oxide with a silver content of less than about 25% by weight, particularly catalysts that can be prepared in a single step using silver deposition. [Summary of the Invention]

[0008] The inventors selected and screened hundreds of promoter compositions and used regression models to fit experimental data to identify trends in catalyst activity and selectivity. By using carefully quantified amounts of certain base and oxygen ion promoters, it was found that lower amounts of silver could be used without unduly sacrificing the activity or selectivity of such catalysts. The catalyst of the present invention, with less than about 25% by weight of silver, actually has a higher promoter content than a catalyst with about 33% by weight of silver. This is a surprising result, as increasing the promoter content by linear scaling often reduces catalyst activity (see US9649621B2 and US9908861B2). For catalysts with less than 25% by weight of silver, it is expected that the promoter content will need to be reduced to compensate for the expected activity penalty as the silver content decreases from about 33% by weight to less than 25% by weight. Therefore, in one embodiment, the present invention is a supported silver catalyst prepared on an alumina-containing support. The support is a high-purity alumina support containing more than about 80 wt% α-alumina and less than about 30 ppm of an acid-leachable alkali metal selected from lithium, sodium, potassium, and mixtures thereof. The weight percentage of alumina and the concentration of the acid-leachable alkali metal are calculated based on the weight of the support. Deposited onto this support are: (A) silver, in an amount of 16 wt% to 25 wt% based on the weight of the catalyst; and (B) a solid promoter comprising cesium, sulfate, rhenium, sodium, and optionally lithium. Preferably, manganese in an amount of 20 ppm to 300 ppm is also deposited onto the catalyst. For promoters other than manganese, the loading is expressed in millimoles of promoter per kilogram of catalyst and scaled by a factor Q, where Q is a dimensionless scaling factor equal to the surface area of ​​the alumina-containing support before silver and promoter deposition, expressed in square meters per gram divided by one square meter per gram.

[0009] The amounts of the components in the solid promoter encapsulation deposited on the catalyst are: CCs / Q in the range of 3.1 to 8.7 mmol / kg catalyst; CNa / Q in the range of 0.5 to 7.5 mmol / kg catalyst; CS / Q in the range of 0.3 to 3.2 mmol / kg catalyst; CRe / Q in the range of 2.4 to 6.9 mmol / kg catalyst; and CLi / Q in the range of 0 to 35 mmol / kg catalyst, wherein CCs, CLI, CNa, CS, and CRe are the amounts of cesium, lithium, sodium, sulfate, and rhenium deposited on the support, expressed in mmol of promoter per kg of catalyst.

[0010] Furthermore, these equal amounts are balanced in the following manner: F1 / Q is in the range of 0.3 to 5.2 mmol / kg catalyst; and F2 / Q is in the range of -5.1 to 6.3 mmol / kg catalyst, wherein F1 and F2 are linear combinations of promoter deposition loadings defined by the following equations: F1 = CCs + 0.032·CLi + 0.47·CNa - (0.72·CS + 0.94·CRe); Equation 1 F2 = CCs - 0.24·CLi - 0.27·CNa + 0.3·CS. Equation 2

[0011] The catalysts described above in this invention demonstrate continuous processes for the direct production of alkyl epoxides from oxygen or oxygen-containing gases. Advantageously, the catalysts of this invention exhibit comparable activity and / or efficiency compared to previously reported catalysts with higher silver content.

Implementation Method

[0013] The present invention described herein provides a novel supported silver catalyst, which has been found to be effective for the direct oxidation of alkylene (olefins), such as ethylene, by oxygen or oxygen-containing gas to form alkylene oxides, such as ethylene oxide, and has a silver content of 25% by weight or less, preferably 24% by weight or less, 23% by weight or less, or even 22% by weight or less. It has been found that good results in ethylene oxide production can be obtained when the silver content is at least 16% by weight, preferably 17% by weight, 18% by weight, or even 19% by weight. More specifically, the supported silver catalyst of the present invention comprises an alumina support containing less than about 30 parts per million, preferably less than 25 parts per million, of an acid-leaching alkali metal, the concentration of which is calculated by weight of the support, wherein the alkali metal is selected from lithium, sodium, potassium, and mixtures thereof.

[0014] Preferably, the supported silver catalyst comprises an alumina support containing at least about 80% or more, preferably at least 90%, 95% or even 98% α-alumina.

[0015] Preferably, the carrier has a surface area expressed in square meters per gram of carrier, which is not less than 0.7 m² / g, 0.8 m² / g, 0.9 m² / g, or 1.0 m² / g. Generally, a larger surface area is preferred, but in some embodiments, the carrier surface area is not greater than 1.5 m² / g, or 1.4 m² / g, or 1.3 m² / g. Suitable carriers can be prepared according to procedures known in the art, such as those described in WO2005 / 039757.

[0016] The following substances are deposited on this carrier: (A) silver; and (B) an additional solid promoter encapsulation comprising cesium, sodium, sulfate, rhenium, and optionally lithium. Preferably, manganese is also deposited as a promoter.

[0017] The preferred content (i.e., amount) of the accelerator will depend in part on the surface area of ​​the carrier, expressed in square meters per gram of carrier surface area. The surface area of ​​the carrier is measured by nitrogen BET, and the pore volume and median pore size are measured by mercury porosimetry, as is commonly known in the art, for example as shown in WO2007 / 123932.

[0018] The amount of manganese, by weight of the catalyst, should be in the range of 20 ppm to 300 ppm when present. Preferably, manganese is present in an amount of at least 50 ppm, 70 ppm or 90 ppm, and at most 250 ppm, 200 ppm or 150 ppm.

[0019] Preferably, cesium is present in an amount of 3.1 mmol, 3.7 mmol, 4.2 mmol or 4.7 mmol, up to 8.7 mmol, 8.4 mmol, 7.8 mmol or 7.3 mmol CCs / Q per kg of catalyst, wherein Q is dimensionless and equal to the surface area of ​​the alumina-containing support prior to the deposition of silver and the promoter, expressed in square meters per gram divided by one square meter per gram, and CCs is the amount of cesium deposited on the support, expressed in mmol promoter / kg catalyst.

[0020] Preferably, the deposited sodium is present in an amount of 0.5, 1.2, 1.8 or 2.5, up to 7.5, 7.0, 6.5 or 6.0 mmol / kg catalyst (CNa / Q), where CNa is the amount of sodium deposited on the support, expressed in mmol promoter / kg catalyst.

[0021] Preferably, the sulfate is present in an amount of 0.3, 0.5 or 0.7 to up to 3.2, 2.7 or 2.2 mmol / kg catalyst CS / Q, wherein CS is the amount of sulfate deposited on the support, expressed in mmol promoter / kg catalyst.

[0022] Preferably, rhenium is present in an amount of 2.4, 2.8 or 3.3, up to 6.9, 6.4 or 6.0 mmol / kg catalyst, wherein CRe is the amount of rhenium deposited on the support, expressed in mmol promoter / kg catalyst.

[0023] Although alternatively, but preferably, the deposited lithium is present in an amount of 0, 3, 6 or 10, up to 35, 30 or 26 mmol / kg catalyst ClI / Q, where ClI is the amount of lithium deposited on the support, expressed in mmol promoter / kg catalyst.

[0024] It should be understood that the amounts of the various promoters mentioned above are the amounts deposited on the support and do not include any amounts that may initially exist in the alumina-containing support, for example as impurities.

[0025] As will be understood by those skilled in the art, the range of the aforementioned promoters is generally greater than that previously reported. Unexpectedly, activity is maintained under these conditions because publications such as US9649621(B2) and US9908861(B2) have indicated that higher amounts of basic promoters generally result in poorer activity in the catalyst.

[0026] Preferably, the promoters are relatively balanced with each other. Preferably, F1 / Q is in the range of 0.3, 0.6, 1.0, 1.5 or 1.9 to 5.2, 4.9, 4.5, 4.1 or 3.7 mmol / kg catalyst, and more preferably, F2 / Q is in the range of -5.1, -4.4, -3.6, -2.5 or -1.8 to 6.3, 5.6, 4.7, 3.5 or 2.7 mmol / kg catalyst, wherein F1 and F2 are defined in Equation 1 and Equation 2, respectively.

[0027] Accelerators can be added in any convenient form, such as cesium hydroxide, cesium acetate, lithium acetate, ammonium sulfate, ammonium perrhenate, sodium acetate, and manganese nitrate. Premixing of manganese accelerator (if present) with ethylenediaminetetraacetic acid (EDTA) may be necessary before adding to the silver impregnation solution.

[0028] In another embodiment, the present invention provides a continuous process for producing alkylene oxides, comprising contacting an alkylene group, preferably ethylene, with oxygen or an oxygen-containing gas in a vapor phase in the presence of a supported silver catalyst comprising any of the components identified below; and conducting the contact under process conditions sufficient to produce alkylene oxides.

[0029] The alkylene (olefin) used in the process of the present invention is preferably characterized by the following structural formula I: R1–C==C–R2||HH (I) wherein R1 and R2 are each independently selected from hydrogen and lower monovalent alkyl groups, preferably C1-6 alkyl groups, such as methyl, ethyl, propyl, butyl, and higher homologues, with up to six carbon atoms. Preferably, R1 and R2 are each independently selected from hydrogen, methyl, and ethyl. More preferably, each R1 and R2 is hydrogen, and the preferred olefin is ethylene. The corresponding alkylene oxide produced in the process of the present invention is preferably characterized by the following structural formula II: O / \ R1–C–C–R2||HH (II) wherein R1 and R2 identified above are related to the reactant olefin. Most preferably, the alkylene oxide is ethylene oxide.

[0030] As known in the prior art, oxygen can be provided as pure molecular oxygen, or alternatively as an oxygen-containing gas, wherein the gas further contains one or more gaseous components, such as gaseous diluents, such as nitrogen, helium, methane, and argon, which are substantially inert to the oxidation process. For example, a suitable oxygen-containing gas is air. In addition, the oxygen-containing gas may contain one or more of the following gaseous components, including water, carbon dioxide, and various gaseous promoters and / or gaseous byproduct inhibitors, as discussed below.

[0031] The relative volume ratio of alkyl groups to oxygen in the feed gas can vary according to any such known and practiced values. Generally, the volume ratio of alkyl groups to oxygen in the feed gas is affected by flammability limitations, as is known in the art, and can vary between about 2 / 1 and about 10 / 1. Similarly, the amount of inert gas, diluent, or other gaseous components (such as water, carbon dioxide, gaseous promoters, and gaseous byproduct inhibitors) can vary according to the range known and practiced in the art.

[0032] The catalyst support used to implement the present invention may be selected from any known alumina support, modified or unmodified, containing high-purity alumina, particularly high-purity alumina containing more than about 80% by weight, preferably more than about 90% by weight, more preferably more than about 95% by weight, and most preferably more than about 98% by weight. The compositional balance generally includes any one of zirconium silicate, other refractory silicates, silicon dioxide, or other metal oxides. In terms of phase composition, the alumina preferably contains α-phase alumina (α-alumina), and more preferably more than about 99% α-phase alumina (α-alumina). As a necessary condition, the high-purity alumina support should contain less than about 30 ppm by weight, preferably less than about 25 ppm by weight, and more preferably less than about 20 ppm by weight of an acid-leaching alkali metal, the concentration of which is calculated by weight of the support, wherein the alkali metal is selected from lithium, sodium, potassium, and mixtures thereof. Preferably, the high-purity alumina carrier contains less than about 30 ppm, more preferably less than about 25 ppm, of acid-leaching sodium by weight.

[0033] In some embodiments, the alumina carrier also contains zirconium silicate (zircon), preferably in any amount of up to about 4%, 3%, or 2% by weight of the carrier.

[0034] There are no limitations to this method, wherein if the alkali is fully present, a low content of alkali metals (Li, Na, K) forming components of the high-purity alumina support is incorporated into the support. Generally, such alkali metals are introduced into the support during its synthesis, for example as impurities in one or more raw materials, or as contaminants in the calcination environment; however, other methods are possible to achieve such alkali metal content. Importantly, the catalyst of the present invention is prepared from a pre-formed high-purity alumina support having an acid-leaching alkali metal of less than about 30 ppm, wherein the alkali metal is selected from lithium, sodium, potassium, and mixtures thereof. Subsequently, the pre-formed high-purity alumina support is intentionally deposited, i.e., added thereto, and silver and a solid promoter encapsulate cesium, sodium, sulfate, rhenium, and optionally lithium and / or manganese.

[0035] Representative examples of materials that can be used as high-purity alumina according to the present invention include such supports manufactured by companies such as Süd Chemie, Inc., Louisville, Ky., and Saint-Gobain NorPro Corp., Akron, OH. Other suppliers may also be available.

[0036] Suitable shapes for high-purity alumina supports include any of the various shapes known for such supports or props, including pellets, blocks, tablets, flakes, granules, rings, spheres, wheels, toroids with star-shaped inner and / or outer surfaces, and the like, suitable for use in fixed-bed reactors. Conventional commercial fixed-bed ethylene oxide reactors are generally filled with catalyst in the form of a plurality of parallel elongated tubes (in a suitable shell), with an outer diameter of about 1 inch to 3 inches (2.5 cm to 7.5 cm) and a length of about 15 feet to 45 feet (4.5 m to 13.5 m). In such fixed-bed reactors, it is desirable to use supports formed in a circular shape, such as spheres, granules, rings, tablets, and the like, with a diameter of about 0.1 inches (0.25 cm) to about 0.8 inches (2 cm).

[0037] Many well-known methods exist for preparing alumina supports suitable for the alkylene oxide catalysts of the present invention. For example, some such methods are described in, for example, International Patent Application Publication WO-A1-2005 / 039757; and US 4,994,587; US 4,994,588; and US 5,504,053, which are incorporated herein by reference. Preferably, an alumina support having a purity of at least 90% and possessing the desired properties (such as desired morphology, surface area, pore volume, and / or pore size distribution) can be prepared by formulating (mixing) raw materials, extruding, drying, and high-temperature calcination. In this case, the raw materials typically include one or more α-alumina powders with different properties, and optionally, materials may be added to provide physical strength, and optionally, burnout material (usually an organic compound) may be used to provide the required porosity after removal by calcination. The limitation is that no amount of alkali metals (Li, Na, K) is added to the binder and burnout material to the extent that the carrier exceeds the required upper limit of less than about 30 ppm by weight. The impurity content in the finished carrier is generally determined by the purity and volatility of the raw materials used during the calcination step. Common impurities include silicon dioxide, alkali and / or alkaline earth metal oxides, and trace amounts of metals and / or non-metallic additives.

[0038] Another known method for preparing high-purity α-alumina with suitable properties comprises: mixing zirconium silicate with boehmite alumina (AlOOH) and / or γ-alumina; solubilizing the boehmite and / or γ-alumina in an acidic mixture containing halide anions (preferably fluoride anions) to provide alumina halide; forming (e.g., by extrusion or pressing) the solubilized alumina halide to provide formed solubilized alumina halide; drying the formed solubilized alumina halide to provide dried-shaped alumina; and calcining the dried-shaped alumina to provide pellets of the α-alumina support. When using the α-alumina support prepared as described in this paragraph, it is important to calcine the alumina solubilized with the acidic mixture containing halide anions before depositing silver or promoting metal, as halides are necessary for forming the desired α-alumina platelets, as described below.

[0039] The high-purity α-alumina carrier used in this invention preferably has a specific surface area of ​​at least about 0.5 m² / g, and more preferably at least about 0.7 m² / g. The surface area is generally not greater than about 10 m² / g, and often not greater than about 5 m² / g, 2 m² / g, or even 1.5 m² / g. The high-purity alumina carrier preferably has a pore volume of at least about 0.5 cm³ / g, and more preferably about 0.5 cm³ / g to about 2.0 cm³ / g; and a median pore size of about 1 micrometer to about 50 micrometers. Preferably, the high-purity alumina has a compressive strength greater than about 12 pounds. The high-purity α-alumina preferably comprises particles, each of which has at least one substantially flat primary surface, has a plate-like or flake-like morphology, is approximately hexagonal in shape (some particles having two or more flat surfaces), and at least 50% of the particles (in numerical terms) have a primary size of less than about 50 micrometers.

[0040] The catalyst of the present invention for the production of alkyl oxides, such as ethylene oxide or propylene oxide, can be prepared using the above-mentioned high-purity α-alumina by impregnating a support with a solution of one or more silver compounds, as is well known in the art. The solid accelerator encapsulation can be performed simultaneously with the silver impregnation, or before or after the silver impregnation. Preferably, the impregnation of silver and the accelerator is carried out simultaneously.

[0041] The concept of a "promoter" is disclosed in this art, referring to a material that, when combined with catalytic silver, contributes to one or more aspects of catalytic efficiency, or otherwise enhances the ability of the catalyst to produce a desired alkylene oxide product, preferably ethylene oxide or propylene oxide. Such promoters are not typically considered catalytic materials in themselves; however, the presence of such promoters in a catalyst has been shown to contribute to one or more beneficial effects on catalytic efficiency, such as increasing the rate or amount of production of the desired product (e.g., by enhancing activity and / or efficiency), reducing the temperature required to achieve a suitable reaction rate, and / or reducing the rate or amount of reactions of undesirable byproducts. Competing reactions occur simultaneously in the reactor, and the key factor in determining the effectiveness of the overall process is the control of these competing reactions. The material referred to as a promoter of the desired reaction may be an inhibitor of another reaction, such as a combustion reaction. Importantly, the effect of the promoter on the overall reaction is beneficial to the efficient production of the desired product, in this case, an alkylene oxide, preferably ethylene oxide.

[0042] It has been found that when the concentrations of various promoter components are carefully controlled, the desired activity and selectivity can be obtained when using catalysts to produce alkyl oxides, and especially ethylene oxides, despite the lower amount of silver deposited on the catalyst. As described above, the concentrations of the components (cesium, sodium, sulfate, rhenium, and optionally lithium and / or manganese) in the solid promoter encapsulation are provided in terms of promoting amount. In this document, the term "promoting amount" refers to the amount of promoter that provides an improvement in one or more catalytic properties of the catalyst when compared with a baseline catalyst containing the same amount of the same component but without that promoting component, and when compared under the same (controlled) process conditions. Examples of catalytic properties include, in particular, flexibility, operability (resistance to run-away), activity, conversion (e.g., conversion of olefins), efficiency (selectivity), stability, and yield. Preferably, the promoter is provided in a "synergistic combination". The term "synergistic combination" refers to the selection of an appropriate amount of promoter that enables a higher efficiency than that achievable under similar operating conditions from individual components encapsulated in a solid promoter. US 4,913,243, incorporated herein by reference, teaches a silver-supported catalyst containing a synergistic combination of cesium and at least one other alkali metal selected from the group consisting of lithium, sodium, potassium, and rubidium. Such patents describe an efficiency equation that can be used to identify synergistic combinations of cesium and other (multiple) alkali metals; however, this efficiency equation represents only one method for characterizing synergistic combinations, and not the only method.

[0043] Well-known methods can be used to analyze the amount of silver, as well as individual components encapsulated in solid accelerators deposited on an alumina support. Those skilled in this art can determine the amount of any of these deposited components using, for example, material balance. For instance, if the alumina support is weighed after the deposition of silver and an alkali metal compound, the difference between the two weights will equal the amount of silver and the alkali metal compound deposited on the support, thus allowing the calculation of the amount of deposited alkali metal. Alternatively, the amount of deposited silver and the alkali metal compound can be calculated based on the ratio of the concentrations of silver to the alkali metal compound in the impregnation solution and the weight picked up from the impregnation solution. Alternatively, any suitable analytical technique for determining elemental composition, such as inductively coupled plasma (ICP) or X-ray fluorescence (XRF) spectroscopy, can be used to determine the amount of deposited components. For example, the amount of cesium present in the support can be determined by XRF analysis of the alumina support. After impregnation with cesium-containing compounds, the impregnated support can be analyzed again by XRF to determine the total amount of cesium present on and deposited on the support. The difference in measurement reflects the amount of cesium deposited on the support.

[0044] In addition to the solid accelerator encapsulation described above, the gaseous accelerator may be the catalyst of the present invention, if desired. The gaseous accelerator is a gaseous compound and / or mixture thereof introduced into a reactor to produce alkyl oxides (preferably ethylene oxide) with gaseous reactants such as ethylene and oxygen. Such accelerators are also called modifiers, inhibitors, or enhancers to further enhance the efficiency of a given catalyst, acting in conjunction with or in addition to a solid accelerator. One or more chlorine-containing components are generally used as gaseous accelerators, as is well known in the art. Other halogen-containing components may also be used to produce similar effects.

[0045] Solid promoter encapsulation typically involves adding the promoter as a compound to the catalyst prior to its use. As used herein, the term "compound" refers to a combination of specific elements having one or more different elements bonded by surface and / or chemical bonding, such as ionic and / or covalent and / or coordination bonding. The terms "ionic" or "ion" refer to a charged chemical portion; "cationic" or "cation" is positive and "anionic" or "anion" is negative. The term "oxyanionic" or "oxyanion" refers to a negatively charged portion containing at least one oxygen atom combined with another element. Thus, an oxyanion is an oxygen-containing anion. It should be understood that ions do not exist in a vacuum, but when added as a compound to a catalyst, they are found to combine with ions in charge balance. Once in the catalyst, the form of the promoter is not always known, and the promoter may be present during catalyst preparation without the addition of a relative ion. For example, a catalyst made with cesium hydroxide can be analyzed to show that the finished catalyst contains cesium but not hydroxide. Similarly, compounds such as alkali metal oxides, such as cesium oxide, although not ionic, can be converted into ionic compounds during catalyst preparation or use. For ease of understanding, solid promoters will be referred to as cations and anions, regardless of their form in the catalyst, as prepared and / or under reaction conditions.

[0046] Typically, the support is impregnated with a catalytic amount of silver, which is any amount of silver capable of catalyzing the direct oxidation of alkylene oxides to the corresponding alkylene oxides with oxygen or oxygen-containing gas. In the manufacture of such catalysts, the support is typically impregnated (once or multiple times) with one or more solutions of silver compounds, based on the weight of the catalyst, such solutions being sufficient to allow silver to be supported on the support in the desired range of about 16% by weight to no more than about 25% by weight. Preferably, the support is impregnated once with a solution containing a silver compound to obtain the desired silver content.

[0047] The silver solution used for impregnating the carrier is preferably composed of a solvent or chelating agent / solvent, such as silver compounds in silver solutions disclosed in the art. The specific silver compound used may be selected from, for example, silver chelates, silver nitrate, silver oxide, or silver carboxylate, such as silver acetate, silver oxalate, silver citrate, silver phthalate, silver lactate, silver propionate, silver butyrate, and silver higher fatty acid salts. Silver oxide chelated with amines is another preferred form of silver used in this invention.

[0048] A wide variety of solvents or solubilizers / solvents can be used to dissolve silver to the desired concentration in the impregnation medium. Among those disclosed that are suitable for this purpose are lactic acid; ammonia; alcohols, such as ethylene glycol; and amines and aqueous mixtures of amines.

[0049] For example, silver oxide (Ag2O) can be advantageously dissolved in a solution of oxalic acid and ethylenediamine, such that the resulting impregnation solution contains about 26% silver oxide, 18% oxalic acid dihydrate, 17% ethylenediamine, 6% monoethanolamine, and 31% water.

[0050] Vacuum impregnation of such solutions onto a support with a porosity of approximately 0.7 cm³ / g generally produces a catalyst containing approximately 20% by weight of silver based on the total weight of the catalyst. Previously, when it was desired to obtain a catalyst with a silver loading of more than approximately 25% or 30%, it was usually necessary to subject the support to at least two or more consecutive silver impregnations with or without a promoter until the desired amount of silver was deposited on the support. However, it is now possible to produce the supported catalyst of the present invention using a single-step silver impregnation process, greatly simplifying the catalyst production process.

[0051] While the silver particle size in the finished catalyst is important, the range is not narrow. Suitable silver particle sizes can range from about 10 angstroms to about 10,000 angstroms in diameter. Preferred silver particle sizes range from more than about 100 angstroms to less than about 5,000 angstroms in diameter. It is desirable that the various components of the silver and solid promoter encapsulation are relatively uniformly dispersed on the alumina support.

[0052] A preferred procedure for depositing silver catalysts and encapsulating solid promoters includes: (1) impregnating a porous alumina support with a solution comprising a solvent or solubilizer, a silver complex, and a solid promoter according to the invention; and (2) a post-treatment of the impregnated support to convert the silver salt into silver metal and to effectively deposit silver and (multiple) promoters onto the external and internal pore surfaces of the support. Deposition of silver and promoters is typically accomplished by heating the support at elevated temperatures to evaporate the liquid within the support and to effectively deposit silver and promoters onto the internal and external surfaces of the support.

[0053] Alternatively, the silver coating and solid promoter encapsulation can be formed on a support by an emulsion or slurry containing a metal component, followed by heating of the support, as described above. However, impregnation of the support is generally a preferred technique for silver deposition because it utilizes silver more effectively than coating processes, which typically fail to deposit substantial silver onto the inner surface of the support. Furthermore, coated catalysts are more susceptible to silver loss due to mechanical abrasion.

[0054] Similar to silver deposition, the soluble salts of the solid accelerator encapsulated components can be dissolved in one or more solvents and / or solubilizers, and are preferably deposited onto the carrier by impregnation. The order in which the carrier surface containing the silver and solid accelerator encapsulated components is impregnated or deposited can vary. Thus, silver, cesium, sodium, sulfate, rhenium, and optionally lithium and / or manganese can be impregnated and deposited concurrently or sequentially, for example, cesium and sodium can be deposited before, during, or after silver deposition onto the carrier. Individual components of the solid accelerator encapsulation can be deposited together or sequentially. For example, silver can be deposited first, followed by the concurrent or sequential deposition of cesium, lithium (if used), sulfate, and rhenium (or combinations thereof); or alternatively, cesium can be deposited first, followed by the concurrent or sequential deposition of silver and lithium (if used), sulfate, and rhenium; or alternatively, if used, lithium can be deposited first, followed by the concurrent or sequential deposition of silver and cesium, sulfate, and rhenium, etc. If two or more impregnations are used, the impregnated carrier is generally dried or calcined and / or roasted between each successive impregnation to ensure that the metal is deposited onto the carrier.

[0055] Subsequently, the silver-impregnated carrier and a solid accelerator comprising cesium, sodium, sulfate, rhenium, and optionally lithium and / or manganese are encapsulated in air and calcined or roasted at a temperature of about 200°C to about 600°C and at atmospheric pressure for a time ranging from about 0.01 hours to about 12 hours. A temperature of 475°C to 525°C for a duration of 5 minutes to 20 minutes is generally preferred. Alternatively, calcination may be carried out in two or more different steps, with the initial step typically performed at a low temperature.

[0056] For example, rhenium components can be provided in various forms, such as as a metal, as a covalent compound, as a cation, or as an anion. The rhenium material that provides enhanced efficiency and / or activity is uncertain and can be an added component or a component generated during the preparation of the catalyst or used as a catalyst. Examples of rhenium compounds include rhenium salts, such as rhenium halides, rhenium oxyhalides, rhenates, perrhenates, oxides, and rhenic acids. However, alkali metal perrhenates, ammonium perrhenate, alkaline earth metal perrhenates, silver perrhenate, other perrhenates, and rhenium heptoxide can also be suitably used, provided that in the case of alkali metal perrhenates, the amount of alkali metal (Cs and / or Rb; and Na and / or K) is taken into account when evaluating the total amount of such cations deposited on the support. Rhenium heptaoxide, or Re₂O₇, hydrolyzes in water to form perrhenic acid, HReO₄, or hydrogen perrhenate. Therefore, for the purposes of this specification, rhenium heptaoxide can be considered a perrhenate, i.e., a monoanion ReO₄.

[0057] Another preferred class of promoters and catalyst stabilizers that can be used with the present invention includes a manganese component. In many cases, the manganese component can enhance the activity, efficiency, and / or stability of the catalyst. The manganese substance that provides enhanced activity, efficiency, and / or stability is uncertain and can be an added component or a component generated during catalyst preparation or use as a catalyst. Manganese components include, but are not limited to, manganese acetate, ammonium manganese sulfate, manganese citrate, manganese dithionate, manganese oxalate, manganese nitrate, manganese sulfate, and manganate anions (e.g., permanganate anions), and mixtures thereof. To stabilize the manganese component in some impregnation solutions, it may be necessary to add a chelating compound, such as ethylenediaminetetraacetic acid (EDTA) or a suitable salt thereof.

[0058] The (multiple) promotion effects provided by solid promoter encapsulation and optional gas-phase promoter can be affected by several variables, such as reaction conditions, catalyst preparation technology, surface area and pore structure, surface chemistry of the support, and concentration of promoter present in the catalyst.

[0059] This invention is applicable to any epoxidation reaction suitable for a reactor, such as a fixed-bed reactor, a continuous stirred tank reactor (CSTR), and a fluid bed reactor, which are numerous and well known to those skilled in the art and do not need to be described in detail herein. Those skilled in the art can readily determine whether to recover unreacted feedstock, employ a single-pass system, or use a continuous reaction to increase the desirability of ethylene conversion by using reactors in a series of configurations. The specific operating mode chosen can be specified by process economics. The conversion of olefins (alkylene oxides), preferably ethylene, to olefin oxides, preferably ethylene oxide, can be carried out, for example, by continuously introducing a feedstock containing olefins (e.g., ethylene) and oxygen or oxygen-containing gas into a catalyst-containing reactor at a temperature of about 200°C to about 300°C and a pressure that can vary from about 5 atmospheres (506 kPa) to about 30 atmospheres (3.0 MPa), depending on the desired mass rate and productivity. The residence time in a large reactor is typically about 0.1 seconds to about 5 seconds. Oxygen can be supplied to the reaction in an oxygen-containing stream, such as air, either commercially available oxygen or oxygen-enriched air. The resulting alkylene oxide, preferably ethylene oxide, is separated and recovered from the reaction products using conventional methods.

[0060] Prior to the production of alkyl epoxides, it is generally desirable to activate or break down the catalyst, as is commonly known to those skilled in the art. A suitable activation scheme is to expose the supported catalyst at 245°C with a near-optimal chloroethane concentration for two to five days to rapidly achieve optimal efficiency.

[0061] As is well known to those skilled in the art, the catalysts disclosed herein can be used under a wide range of process conditions.

[0062] The following examples illustrate the purpose of this invention; however, these examples are not intended to limit the invention in any way. Those skilled in the art will recognize various substitutions and modifications to the examples that fall within the scope of this invention. Examples

[0063] A series of high-purity α-alumina supports having a hollow, shaped geometry and containing more than about 80% by weight of α-alumina and less than about 30 parts per million by weight of an acid-leaching alkali metal (preferably lithium, sodium, and potassium), the weight percentage of alumina and the concentration of the acid-leaching alkali metal, calculated on the weight of the support, were obtained from Saint-Gobain NorPro. Table 1 below shows the properties of supports A to F.

[0064] Table 1. Carrier Properties carrier Carrier shape Surface area (m²) 2 / g) Pore ​​volume (cm³) 3 / g) Bulk density (kg / m³) 3 ) Zircon (per thousand parts) A Five Rings 1.16 0.70 524 twenty one B Five Rings 1.12 0.68 521 twenty two C Five Rings 1.20 0.69 524 twenty two D Five Rings 1.15 0.68 532 twenty three E single ring 1.14 0.61 604 twenty one F single ring 1.05 0.66 561 0 G Five Rings 1.16 0.66 533 twenty two H Five Rings 1.28 0.69 533 18 Silver compound solution

[0065] The silver impregnation solution is prepared according to the procedure described in US 2009 / 0177000 A1 and contains approximately 27% silver oxide, 18% oxalate dihydrate, 17% ethylenediamine, 6% monoethanolamine, and 31% water. Individual accelerator solutions are added to this pre-prepared silver solution in pre-calculated amounts to produce the desired accelerator composition on the finished catalyst. The accelerator solutions are synthesized by vacuum impregnation.

[0066] Manganese nitrate (Mn(NO3)2), diammonium ethylenediaminetetraacetate ((NH4)2H2(EDTA)), cesium hydroxide (CsOH), lithium acetate (LiOCOCH3), and ammonium sulfate ((NH4)2SO4) are used as pre-prepared solutions. The manganese and EDTA solutions are pre-mixed before adding the pre-prepared silver solution. Before use, the CsOH solution is generally diluted with deionized water to the required cesium concentration. The sodium acetate (NaOCOCH3) accelerator solution is prepared by dissolving the salt in deionized water. The ammonium perrhenate (NH4ReO4) accelerator solution is prepared by dissolving the salt in deionized water that is gradually heated to 40°C to 50°C while stirring. Vacuum impregnation catalyst synthesis.

[0067] The catalysts in Examples 1-10 were synthesized by vacuum impregnation. The synthesis apparatus consisted of a lower vacuum container, which was sealed at the top by a Teflon stopper connected to a second container with a stopcock. The synthesis began by loading bare alumina-containing support particles into the lower vacuum container. Subsequently, the lower container was sealed and placed under vacuum for 15 minutes. After evacuation, a silver impregnation solution with the desired promoter concentration was added to the top container. The stopper was opened to introduce the promoting silver solution under vacuum. The vacuum was then released, and the support was immersed in the impregnation solution for 15 minutes, followed by 15 minutes of evacuation. The new impregnated support was placed in a single layer on a stainless steel mesh tray and calcined in an air oven at 500°C for 10 minutes. The catalyst was cooled and weighed to estimate the Ag loading after impregnation. Synthesis of initially wet impregnated catalyst

[0068] The catalysts of Examples 11-45 were synthesized by a wet impregnation method. Unpromoted silver-impregnated pellets (prepared using a vacuum impregnation method similar to that described above using carrier A; 12.5 wt.% silver) were pulverized and sieved to 30-50 mesh, aliquoted into 500 mg portions, and placed in synthesis tubes. The promoter solution consisted of deionized water, cesium hydroxide, lithium acetate, ammonium acetate, ammonium sulfate, ammonium perrhenate, and manganese nitrate tetrahydrate. The manganese solution was stabilized with diammonium ethylenediaminetetraacetate and monoethanolamine. The promoter solution was combined and subsequently added to the silver-impregnated powder, followed by mixing to achieve homogeneity. After impregnation, the sample was dried at 80°C for 30 minutes, and then calcined in a box oven at 500°C under airflow for 10 minutes. Elemental analysis of the catalyst synthesized by vacuum impregnation.

[0069] For silver, cesium, sulfate, rhenium, and manganese, elemental analysis was performed by X-ray fluorescence spectrometry (XRF). For lithium and sodium, elemental analysis was performed by inductively coupled plasma optical emission spectrometry (ICP-OES). The testing protocol was a continuous stirred tank reactor.

[0070] For catalyst performance testing in a reverse-mixing Berty autoclave reactor (RotoBerty), 30 cm³ (̴ 20 g) of catalyst was loaded. The reactor was heated to 245°C under a nitrogen flow. Feed gas was introduced once the temperature reached 220°C. Reaction conditions were: a total flow rate of 7.1 standard cubic feet per hour (scfh) (201 standard liters per hour), a gas hourly space velocity (GHSV) of ̴ 6800 h⁻¹, a total pressure of 275 psig (1900 kPa standard), and a gas inlet concentration of 30% C₂H₄, 0.7% C₂H₆, 8% O₂, 1% CO₂, 4 ppm to 5 ppm ethane chloride (ECL), and equilibrium nitrogen (by volume). Unless otherwise specified in the examples below, the catalyst was operated under these "break-in" conditions for 2 to 3 days. After catalyst activation, the temperature was lowered to 235°C, and the gas-phase promoter was optimized by varying the inlet chloroethane concentration from low to high. Cl optimization was also performed using outlet concentrations controlled at 28.3% C2H4, 6.4% O2, and 1.5% CO2. Performance was stabilized at each chloroethane concentration, and average values ​​were recorded. Optimal performance is reported as selectivity and activity (ΔEO) at the inlet ECl concentration, where selectivity is maximized. ΔEO is the difference between the outlet and inlet ethylene oxide concentrations, corrected for changes in mole volume across the reactor, and measured as a mole percentage. The reactor inlet and outlet concentrations of ethylene oxide, expressed as a mole percentage (EO inlet and EO outlet, respectively), are calculated as follows: ΔEO % = SF × EO outlet – EO inlet. The term "SF" or "Shrink Factor" represents the net volume reduction due to ethylene oxide production. For each mole of ethylene oxide produced, a net reduction of 0.5 moles in the total gas volume results in a corresponding reduction in the volumetric flow rate. SF is generally calculated as follows: (200 + EO inlet) ÷ (200 + EO outlet), where EO inlet and EO outlet represent the concentrations in the reactor inlet and outlet gas mixtures, expressed as mole percentages, respectively. Test protocol: plug flow reactor.

[0071] High-throughput catalytic testing is performed in a High Pressure Reactor Assembly Module (HPRAM) system, as described in, for example, US 9,649,621. The HPRAM reactor system includes a gas feed system, 48 reactors, 2 outlet modules, and 3 analyzers (Siemens MAXUM-II gas chromatography (GC)). Seven of the 48 reactors are retained blanks to determine the gas inlet concentration.

[0072] Tests were conducted at constant catalyst bed volume (Vcatbed = 0.1498 cm³), constant flow rate (19.6 standard cubic centimeters / minute), and constant gas space velocity per hour (GHSV = 7850 / hr.). The catalyst was charged into the reactor in powder form (30 mesh / 50 mesh) without inert diluent. The catalyst was loaded into the reactor tube by mass using the formula given below: Loading mass (mg) = Vcatbed · PDcar · 100% / (100% – AGWT) where PDcar is the bulk density of the carrier listed in Table 1, and AGWT is the silver content of the catalyst in wt.%. It should be noted that the entire pellet bulk density used in these tests is for a model tested on a larger scale. For the tests reported in Tables 6 and 8, the catalyst loading masses were 100.0 mg and 93.8 mg to 100.3 mg, respectively.

[0073] The reactor is loaded with a catalyst and subsequently heated under an inert gas flow (helium or nitrogen), after which a feed gas, except for oxygen, is introduced into the reactor. Oxygen is then added last (generally after 2 to 3 minutes) to prevent any chance of a combustible mixture forming in the system. Subsequently, for testing purposes, the gas pressure and flow rate are maintained at 10 barg and 19.6 standard cubic centimeters per minute, respectively.

[0074] The catalyst tests (catalysts 11-45) reported in Table 6 were conducted as follows. After a 2-day activation period (245°C, 28 vol.% inlet ethylene, 4.8 vol.% inlet oxygen, 2.0 vol.% inlet carbon dioxide, 4 ppmv inlet chloroethane, 0.14 vol.% inlet ethane, 11 vol.% inlet methane, equilibrium inert), the temperature was lowered to 235°C, and the gas inlet was adjusted to 32 vol.% ethylene, 7.6 vol.% oxygen, 1.5 vol.% carbon dioxide, 0.14 vol.% ethane, 11 vol.% methane, and varying amounts of chloroethane promoter. Gas-phase promoter optimization was performed in a steady-state manner from low to high, with chloroethane ranging from 0.5 ppmv to 6.0 ppmv.

[0075] The catalyst tests reported in Table 8 (catalysts 46-57) are average values ​​for N=2 to 5 reactors. These tests were conducted as follows. After a 2-day activation cycle (245°C, 27 vol.% inlet ethylene, 4.7 vol.% inlet oxygen, 1.7 vol.% inlet carbon dioxide, 1.4 ppmv inlet chloroethane, 0.12 vol.% inlet ethane, 11 vol.% inlet methane, equilibrium inert), the gas inlet was adjusted to 32 vol.% ethylene, 7.4 vol.% oxygen, 1.3 vol.% carbon dioxide, 1.8 vol.% ethane, 0.7 ppmv chloroethane, and 11 vol.% methane. After 5 hours of operation (T=245°C and 1.8 vol.% ethane), the temperature was reduced to 235°C and the ethane inlet was reduced to 0.12 vol.%. Subsequently, the gas-phase promoter optimization system was carried out in a steady-state manner from low to high, with ethane chloride ranging from 0.96 ppmv to 3.84 ppmv. The resulting catalyst was catalyst 1.

[0076] According to the vacuum impregnation method presented above, 50 g of support A is converted into "catalyst 1". The following quantities were used to prepare the impregnation solution: 200 g silver solution (27.41% Ag), 0.1987 g Mn(NO3)2 solution (0.1570 g Mn / g solution), 1.0963 g (NH4)2H2(EDTA) solution (0.4030 g EDTA / g solution), 2.4931 g CsOH solution (0.1100 g Cs / g solution), 0.6179 g LiOCOCH3 solution (0.0255 g Li / g solution), 0.3472 g NaOCOCH3 solution (0.0551 g Na / g solution), 0.1238 g (NH4)2SO4 solution (0.2908 g SO4 / g solution), and 9.4962 g NH4ReO4 solution (0.0320 g Re / g solution).

[0077] The resulting catalyst contains 19.2% Ag by weight, as measured by XRF. Target accelerator concentrations for all accelerators are listed in Table 3. Table 4 provides a comparison of target accelerator concentrations for the analyzed accelerator concentrations. Catalyst 2

[0078] According to the vacuum impregnation method presented above, 50 g of support B is converted into "catalyst 2". The following quantities were used to prepare the impregnation solution: 200 g silver solution (27.41% Ag), 0.1912 g Mn(NO3)2 solution (0.1570 g Mn / g solution), 1.0551 g (NH4)2H2(EDTA) solution (0.4030 g EDTA / g solution), 2.9531 g CsOH solution (0.1100 g Cs / g solution), 0.7319 g LiOCOCH3 solution (0.0255 g Li / g solution), 0.4551 g NaOCOCH3 solution (0.0498 g Na / g solution), 0.1467 g (NH4)2SO4 solution (0.2908 g SO4 / g solution), and 11.1440 g NH4ReO4 solution (0.0323 g Re / g solution).

[0079] The resulting catalyst contains 20% Ag by weight, as determined gravimetrically. The target accelerator concentrations for all accelerators are listed in Table 3. Catalyst 3

[0080] According to the vacuum impregnation method presented above, 50 g of support C is converted into "catalyst 3". The following quantities are used to prepare the impregnation solution: 200 g silver solution (26.8% Ag), 0.1883 g Mn(NO3)2 solution (0.1560 g Mn / g solution), 1.0399 g (NH4)2H2(EDTA) solution (0.4001 g EDTA / g solution), 1.5583 g CsOH solution (0.1090 g Cs / g solution), 0.6911 g LiOCOCH3 solution (0.0255 g Li / g solution), 0.4214 g NaOCOCH3 solution (0.0491 g Na / g solution), 0.0920 g (NH4)2SO4 solution (0.2944 g SO4 / g solution), and 5.2368 g NH4ReO4 solution (0.0318 g Re / g solution).

[0081] The resulting catalyst contains 21% Ag by weight, as determined gravimetrically. The target accelerator concentrations for all accelerators are listed in Table 3. Catalyst 4

[0082] According to the vacuum impregnation method presented above, 50 g of support C is converted into "catalyst 4". The following quantities are used to prepare the impregnation solution: 200 g silver solution (26.8% Ag), 0.1882 g Mn(NO3)2 solution (0.1560 g Mn / g solution), 1.0397 g (NH4)2H2(EDTA) solution (0.4001 g EDTA / g solution), 1.8695 g CsOH solution (0.1090 g Cs / g solution), 1.7325 g LiOCOCH3 solution (0.0255 g Li / g solution), 0.2407 g NaOCOCH3 solution (0.0491 g Na / g solution), 0.1002 g (NH4)2SO4 solution (0.2944 g SO4 / g solution), and 5.2689 g NH4ReO4 solution (0.0316 g Re / g solution).

[0083] The resulting catalyst contains 20% Ag by weight, as determined by gravimetric method. The target accelerator concentrations for all accelerators are listed in Table 3. Catalyst 5

[0084] According to the vacuum impregnation method presented above, 50 g of support C is converted into "catalyst 5". The following quantities were used to prepare the impregnation solution: 200 g silver solution (27.3% Ag), 0.1921 g Mn(NO3)2 solution (0.1560 g Mn / g solution), 1.0607 g (NH4)2H2(EDTA) solution (0.4001 g EDTA / g solution), 1.9429 g CsOH solution (0.1105 g Cs / g solution), 1.0626 g LiOCOCH3 solution (0.0255 g Li / g solution), 0.3661 g NaOCOCH3 solution (0.0491 g Na / g solution), 0.1018 g (NH4)2SO4 solution (0.2944 g SO4 / g solution), and 6.9093 g NH4ReO4 solution (0.0316 g Re / g solution).

[0085] The resulting catalyst consists of 19.7% Ag by weight, as measured by XRF. Target accelerator concentrations for all accelerators are listed in Table 3. Table 4 provides a comparison of target accelerator concentrations for the analyzed accelerator concentrations. Catalyst 6

[0086] According to the vacuum impregnation method presented above, 50 g of support D is converted into "catalyst 6". The following quantities were used to prepare the impregnation solution: 200 g silver solution (27.37% Ag), 0.1926 g Mn(NO3)2 solution (0.1560 g Mn / g solution), 1.0639 g (NH4)2H2(EDTA) solution (0.4001 g EDTA / g solution), 1.9487 g CsOH solution (0.1105 g Cs / g solution), 1.3732 g LiOCOCH3 solution (0.0255 g Li / g solution), 0.5383 g NaOCOCH3 solution (0.0500 g Na / g solution), 0.1429 g (NH4)2SO4 solution (0.2944 g SO4 / g solution), and 7.8562 g NH4ReO4 solution (0.0316 g Re / g solution).

[0087] The resulting catalyst consists of 19.5% Ag by weight, as measured by XRF. Target accelerator concentrations for all accelerators are listed in Table 3. Table 4 provides a comparison of target accelerator concentrations for the analyzed accelerator concentrations. Catalyst 7

[0088] According to the vacuum impregnation method presented above, 50 g of support F is converted into "catalyst 7". The following quantities are used to prepare the impregnation solution: 200 g silver solution (27.37% Ag), 0.2020 g Mn(NO3)2 solution (0.1560 g Mn / g solution), 1.1154 g (NH4)2H2(EDTA) solution (0.4001 g EDTA / g solution), 1.8693 g CsOH solution (0.1105 g Cs / g solution), 1.0528 g LiOCOCH3 solution (0.0255 g Li / g solution), 0.2411 g NaOCOCH3 solution (0.0500 g Na / g solution), 0.1014 g (NH4)2SO4 solution (0.2944 g SO4 / g solution), and 5.3403 g NH4ReO4 solution (0.0316 g Re / g solution).

[0089] The resulting catalyst consists of 16.5% Ag by weight, as measured by XRF. Target accelerator concentrations for all accelerators are listed in Table 3. Table 4 provides a comparison of target accelerator concentrations for the analyzed accelerator concentrations. Catalyst 8

[0090] According to the vacuum impregnation method presented above, 50 g of support E is converted into "catalyst 8". The following quantities are used to prepare the impregnation solution: 200 g silver solution (27.3% Ag), 0.2017 g Mn(NO3)2 solution (0.1560 g Mn / g solution), 1.1140 g (NH4)2H2(EDTA) solution (0.4001 g EDTA / g solution), 1.9760 g CsOH solution (0.1105 g Cs / g solution), 1.1105 g LiOCOCH3 solution (0.0255 g Li / g solution), 0.2579 g NaOCOCH3 solution (0.0491 g Na / g solution), 0.1074 g (NH4)2SO4 solution (0.2944 g SO4 / g solution), and 5.6454 g NH4ReO4 solution (0.0316 g Re / g solution).

[0091] The resulting catalyst consists of 17.1% Ag by weight, as measured by XRF. Target accelerator concentrations for all accelerators are listed in Table 3. Table 4 provides a comparison of target accelerator concentrations for the analyzed accelerator concentrations. Catalyst 9

[0092] Apart from the change in calcination treatment, 50g of carrier D was converted into "catalyst 9" according to the vacuum impregnation method presented above. After impregnation and drainage, the wet pellet was treated in an air oven at 110°C for 10 minutes, and then calcined at 500°C for 10 minutes. The following quantities were used to prepare the impregnation solution: 200 g silver solution (27.37% Ag), 0.2022 g Mn(NO3)2 solution (0.1560 g Mn / g solution), 1.1167 g (NH4)2H2(EDTA) solution (0.4001 g EDTA / g solution), 1.6208 g CsOH solution (0.1105 g Cs / g solution), 0.7314 g LiOCOCH3 solution (0.0255 g Li / g solution), 0.4388 g NaOCOCH3 solution (0.0500 g Na / g solution), 0.0969 g (NH4)2SO4 solution (0.2944 g SO4 / g solution), and 5.5549 g NH4ReO4 solution (0.0316 g Re / g solution).

[0093] The resulting catalyst consists of 21.1% Ag by weight, as measured by XRF. Target accelerator concentrations for all accelerators are listed in Table 3. Table 4 provides a comparison of target accelerator concentrations for the analyzed accelerator concentrations. Catalyst 10

[0094] Apart from the change in calcination treatment, 50g of carrier D was converted into "catalyst 10" according to the vacuum impregnation method presented above. After impregnation and drainage, the wet pellet was treated in an air oven at 90°C for 90 minutes, and then calcined at 500°C for 10 minutes. The following quantities were used to prepare the impregnation solution: 200 g silver solution (27.37% Ag), 0.1901 g Mn(NO3)2 solution (0.1560 g Mn / g solution), 1.0502 g (NH4)2H2(EDTA) solution (0.4001 g EDTA / g solution), 1.5243 g CsOH solution (0.1105 g Cs / g solution), 0.6878 g LiOCOCH3 solution (0.0255 g Li / g solution), 0.4127 g NaOCOCH3 solution (0.0500 g Na / g solution), 0.0911 g (NH4)2SO4 solution (0.2944 g SO4 / g solution), and 5.2241 g NH4ReO4 solution (0.0316 g Re / g solution).

[0095] The resulting catalyst consists of 22.4% Ag by weight, as measured by XRF. Target accelerator concentrations for all accelerators are listed in Table 2. Table 3 provides a comparison of target accelerator concentrations for the analyzed accelerator concentrations.

[0096] Table 2. Target synthesis promoter concentrations of catalysts 1-10 catalyst carrier Cs (mmol / kg) Li (mmol / kg) Na (mmol / kg) SO4 (mmol / kg) Re (mmol / kg) Mn (ppm) F1 (mmol / kg) F2 (mmol / kg) 1 A 7.61 8.36 3.09 1.38 6.01 115 2.68 5.18 2 B 9.36 10.37 3.78 1.70 7.41 115 3.29 6.36 3 C 5.00 9.94 3.52 1.10 3.50 115 2.89 2.00 4 C 6.00 24.92 2.00 1.21 3.50 115 3.58 -0.16 5 C 6.20 14.98 3.00 1.20 4.50 115 3.00 2.15 6 D 6.20 19.31 4.48 1.68 5.10 115 2.92 0.86 7 F 5.67 14.12 1.91 1.13 3.31 115 3.10 2.11 8 E 6.00 14.98 2.00 1.21 3.50 115 3.26 2.23 9 D 4.91 9.80 3.48 1.08 3.44 115 2.85 1.95 10 D 4.91 9.80 3.48 1.08 3.44 115 2.85 1.95

[0097] Table 3. Accelerator concentration, analysis relative to synthesis target catalyst method Cs (ppm) Li (ppm) Na (ppm) SO4 (ppm) Re (ppm) Mn (ppm) 1 analyze 1008 60 79 132 1117 117 5 analyze 788 109 95 145 843 116 6 analyze 837 136 112 156 922 115 7 analyze 700 90 54 109 536 92 8 analyze 743 99 53 109 588 106 9 analyze 733 76 95 108 676 128 10 analyze 724 72 93 110 686 125 1 Target 1011 58 71 133 1120 115 5 Target 824 104 69 115 838 115 6 Target 824 134 103 161 950 115 7 Target 754 98 44 109 616 115 8 Target 798 104 46 116 652 115 9 Target 653 68 80 104 640 115 10 Target 653 68 80 104 640 115 1 delta -3 2 8 -1 -3 2 5 delta -36 5 26 30 5 1 6 delta 13 2 9 -5 -28 0 7 delta -54 -8 10 0 -80 -twenty three 8 delta -55 -5 7 -7 -64 -9 9 delta 80 8 15 4 36 13 10 delta 71 4 13 6 46 10

[0098] Table 4 shows the catalytic performance of catalysts 1-10 using the CSTR test protocol. All 10 catalysts are inventive, and each achieves a selectivity of not less than 88.4% and an activity of not less than ΔEO = 1.23 vol.%.

[0099] Table 4. Catalyst performance, catalysts 1-10. catalyst Selectivity, % ΔEO, vol.% 1 88.8 1.23 2 88.4 1.36 3 89.1 1.48 4 88.9 1.45 5 88.9 1.5 6 88.6 1.44 7 88.5 1.5 8 89.9 1.41 9 89.2 1.45 10 88.7 1.54

[0100] Catalyst 11-45 was prepared using the initial wet method presented above, and its performance was evaluated in an HPRAM reactor according to the test protocol of a plug-flow reactor. Target promoter concentrations are given in Table 5. Performance results are given in Table 6 and Figure 1. As shown in Figure 1, the selectivity in the ranges of 87.1% to 91.6% and 84.3% to 86.4% represents the inventive and comparative catalysts, respectively.

[0101] Table 5. Target promoter concentration of catalyst 11-45 catalyst type Cs / Q (mmol / kg) Li / Q (mmol / kg) Na / Q (mmol / kg) S / Q (mmol / kg) Re / Q (mmol / kg) Mn (ppm) F1 / Q (mmol / kg) F2 / Q (mmol / kg) 11 Inventive (inv) 5.34 19.40 2.59 1.45 3.88 115 2.49 0.43 12 Inventive 5.34 12.93 2.59 1.45 3.10 115 3.01 1.98 13 Inventive 5.34 12.93 2.59 1.03 3.88 115 2.58 1.85 14 Inventive 5.34 12.93 1.29 1.45 3.88 115 1.68 2.33 15 Inventive 5.34 12.93 2.59 0.62 4.66 115 2.15 1.73 16 Inventive 5.34 12.93 3.88 1.45 3.88 115 2.89 1.63 17 Inventive 5.34 6.47 2.59 0.62 3.88 115 2.67 3.28 18 Inventive 5.80 8.88 3.05 1.47 4.59 149 2.15 3.29 19 Inventive 4.29 8.88 3.05 1.47 4.59 81 0.64 1.77 20 Inventive 5.80 8.88 1.02 1.47 3.39 81 2.32 3.84 twenty one Inventive 6.31 8.33 1.02 1.37 2.99 58 3.25 4.45 twenty two Inventive 6.31 2.78 3.05 1.37 2.99 173 4.03 5.23 twenty three Inventive 6.31 8.33 3.05 1.37 4.99 58 2.33 3.90 twenty four Inventive 4.31 14.22 3.02 0.91 3.02 115 2.69 0.36 25 Comparison (comp) 5.39 12.93 4.53 0.46 2.26 115 5.47 1.20 26 Inventive 4.31 8.62 1.06 0.91 3.02 115 1.59 2.23 27 Comparison 3.23 12.93 4.53 0.46 2.26 115 3.32 -0.96 28 Inventive 6.47 30.17 0.86 1.03 3.77 115 3.55 -0.70 29 Inventive 5.17 21.55 0.60 1.03 3.02 115 2.56 0.15 30 Comparison 3.88 30.17 2.59 1.03 2.26 115 3.19 -3.75 31 Comparison 6.47 12.93 2.59 1.03 2.26 115 5.22 2.97 32 Comparison 6.47 30.17 0.86 1.03 2.26 115 4.96 -0.70 33 Inventive 5.44 23.29 5.43 0.88 3.30 115 5.01 -1.35 34 Inventive 6.68 16.64 5.43 2.05 5.50 115 3.12 1.84 35 Comparison 5.26 21.55 3.19 2.76 5.66 115 0.15 0.05 36 Inventive 5.26 21.55 4.92 1.90 4.31 115 2.84 -0.67 37 Inventive 6.29 21.55 4.91 2.76 5.18 115 2.44 0.62 38 Inventive 5.78 21.55 4.91 1.90 5.17 115 2.55 -0.15 39 Inventive 5.77 21.55 6.64 1.89 5.17 115 3.36 -0.63 40 Inventive 5.26 21.55 6.64 1.03 6.03 115 2.65 -1.40 41 Inventive 5.74 21.55 6.64 2.76 5.17 115 2.70 -0.40 42 Inventive 6.29 21.55 6.64 2.76 4.31 115 4.06 0.16 43 Inventive 6.29 21.55 3.19 2.76 4.31 115 2.44 1.09 44 Inventive 5.26 21.55 6.64 2.76 4.31 115 3.03 -0.88 45 Inventive 6.29 21.55 3.19 1.90 5.19 115 2.24 0.83

[0102] Table 6. Catalytic efficiency of catalyst 11-45 catalyst type Selectivity, % ΔEO, vol.% 11 Inventive 89.2 1.76 12 Inventive 89.0 1.68 13 Inventive 90.1 1.50 14 Inventive 89.8 1.52 15 Inventive 90.1 1.46 16 Inventive 90.4 1.45 17 Inventive 89.9 1.42 18 Inventive 88.7 1.30 19 Inventive 87.3 1.45 20 Inventive 88.3 1.47 twenty one Inventive 89.1 1.39 twenty two Inventive 88.0 1.18 twenty three Inventive 90.3 1.15 twenty four Inventive 88.6 1.72 25 Comparison 84.4 1.80 26 Inventive 87.7 1.38 27 Comparison 86.4 1.83 28 Inventive 88.7 1.36 29 Inventive 87.1 1.80 30 Comparison 85.2 2.05 31 Comparison 84.3 1.84 32 Comparison 84.6 1.89 33 Inventive 87.8 1.30 34 Inventive 91.5 1.20 35 Comparison 85.0 1.65 36 Inventive 91.4 1.26 37 Inventive 91.3 1.31 38 Inventive 91.3 1.40 39 Inventive 91.4 1.31 40 Inventive 90.6 1.45 41 Inventive 91.5 1.25 42 Inventive 91.5 0.88 43 Inventive 91.4 1.10 44 Inventive 91.6 1.02 45 Inventive 90.4 1.27

[0103] Table 7. Target promoter concentrations for catalysts 46-57 Example type Cs (ppm) Li (ppm) Na (ppm) SO4 (ppm) Re (ppm) Mn (ppm) F1 / Q F2 / Q 46 Inventive 801 130 100 157 924 112 2.4 0.7 47 Inventive 836 136 105 163 964 0 2.6 0.8 48 Inventive 794 129 99 155 915 265 2.4 0.7 49 Inventive 860 140 108 168 991 203 2.6 0.8 50 Inventive 857 139 107 167 988 59 2.6 0.8 51 Inventive 832 0 104 162 959 116 2.0 4.8 52 Inventive 880 0 110 172 1014 0 2.1 5.1 53 Inventive 809 0 158 207 933 113 2.6 4.2 54 Comparison 486 27 34 117 341 73 1.5 2.1 55 Comparison 495 28 35 119 347 74 1.5 2.1 56 Inventive 858 140 108 168 989 109 2.4 0.7 57 Inventive 908 148 114 178 1047 115 2.5 0.7

[0104] Table 8. Catalytic efficiency of catalysts 46-57 catalyst type N Selectivity (%) ΔEO (vol.%) 46 Inventive 5 90.5 1.30 47 Inventive 3 91.5 1.23 48 Inventive 3 90.1 1.16 49 Inventive 3 90.3 1.19 50 Inventive 3 90.9 1.16 51 Inventive 3 86.7 0.99 52 Inventive 3 87.1 0.98 53 Inventive 3 88.6 1.22 54 Comparison 2 84.9 1.02 55 Comparison 2 86.3 1.23 56 Inventive 3 89.4 1.16 57 Inventive 3 91.0 1.16 Catalyst 46

[0105] According to the vacuum impregnation method presented above, 50.09 g of support G was converted into "catalyst 46". The following amounts were used to prepare the impregnation solution: 165.04 g silver solution (25.69 wt.% Ag), 0.6013 g Mn(NO3)2 solution (38.00 mg Mn / g solution), 0.8065 g (NH4)2H2(EDTA) solution (401.0 mg EDTA / g solution), 1.4623 g CsOH solution (111.9 mg Cs / g solution), 2.2177 g LiOCOCH3 solution (12.00 mg Li / g solution), 0.4091 g NaOCOCH3 solution (50.00 mg Na / g solution), 0.7992 g (NH4)2SO4 solution (40.00 mg SO4 / g solution), and 5.8594 g NH4ReO4 solution (32.20 g Re / g solution). The resulting catalyst contained 21.02 wt.% Ag, as determined by gravimetric analysis. The target accelerator concentrations for all accelerators are listed in Table 7. Catalyst 47

[0106] According to the vacuum impregnation method presented above, 50.21 g of support G was converted into "catalyst 47". The following amounts were used to prepare the impregnation solution: 165.35 g silver solution (27.62 wt.% Ag), 0.0000 g Mn(NO3)2 solution (38.00 mg Mn / g solution), 0.0000 g (NH4)2H2(EDTA) solution (401.0 mg EDTA / g solution), 1.6822 g CsOH solution (111.9 mg Cs / g solution), 2.5511 g LiOCOCH3 solution (12.00 mg Li / g solution), 0.4704 g NaOCOCH3 solution (50.00 mg Na / g solution), 0.9195 g (NH4)2SO4 solution (40.00 mg SO4 / g solution), and 6.7391 g NH4ReO4 solution (32.20 g Re / g solution). The resulting catalyst contained 20.54 wt.% Ag, as determined by gravimetric analysis. Target accelerator concentrations for all accelerators are listed in Table 7. Catalyst 48

[0107] According to the vacuum impregnation method presented above, 50.08 g of support G was converted into "catalyst 48". The following amounts were used to prepare the impregnation solution: 165.20 g silver solution (25.69 wt.% Ag), 1.5226 g Mn(NO3)2 solution (38.00 mg Mn / g solution), 2.0444 g (NH4)2H2(EDTA) solution (401.0 mg EDTA / g solution), 1.5497 g CsOH solution (111.9 mg Cs / g solution), 2.3497 g LiOCOCH3 solution (12.00 mg Li / g solution), 0.4337 g NaOCOCH3 solution (50.00 mg Na / g solution), 0.8471 g (NH4)2SO4 solution (40.00 mg SO4 / g solution), and 6.2084 g NH4ReO4 solution (32.20 g Re / g solution). The resulting catalyst contained 19.69 wt.% Ag, as determined by gravimetric analysis. The target accelerator concentrations for all accelerators are listed in Table 7. Catalyst 49

[0108] According to the vacuum impregnation method presented above, 50.16 g of support G was converted into "catalyst 49". The following amounts were used to prepare the impregnation solution: 165.25 g silver solution (25.69 wt.% Ag), 1.0960 g Mn(NO3)2 solution (38.00 mg Mn / g solution), 1.4711 g (NH4)2H2(EDTA) solution (401.0 mg EDTA / g solution), 1.5730 g CsOH solution (111.9 mg Cs / g solution), 2.3847 g LiOCOCH3 solution (12.00 mg Li / g solution), 0.4403 g NaOCOCH3 solution (50.00 mg Na / g solution), 0.8597 g (NH4)2SO4 solution (40.00 mg SO4 / g solution), and 6.3016 g NH4ReO4 solution (32.20 g Re / g solution). The resulting catalyst contained 21.02 wt.% Ag, as determined by gravimetric analysis. The target accelerator concentrations for all accelerators are listed in Table 7. Catalyst 50

[0109] According to the vacuum impregnation method presented above, 50.23 g of support G was converted into "catalyst 50". The following amounts were used to prepare the impregnation solution: 165.01 g silver solution (25.69 wt.% Ag), 0.3035 g Mn(NO3)2 solution (38.00 mg Mn / g solution), 0.4073 g (NH4)2H2(EDTA) solution (401.0 mg EDTA / g solution), 1.4903 g CsOH solution (111.9 mg Cs / g solution), 2.2595 g LiOCOCH3 solution (12.00 mg Li / g solution), 0.4168 g NaOCOCH3 solution (50.00 mg Na / g solution), 0.8144 g (NH4)2SO4 solution (40.00 mg SO4 / g solution), and 5.9709 g NH4ReO4 solution (32.20 g Re / g solution). The resulting catalyst contained 22.06 wt.% Ag, as determined by gravimetric analysis. The target accelerator concentrations for all accelerators are listed in Table 7. Catalyst 51

[0110] According to the vacuum impregnation method presented above, 50.10 g of support G was converted into "catalyst 51". The following amounts were used to prepare the impregnation solution: 165.16 g silver solution (25.69 wt.% Ag), 0.6126 g Mn(NO3)2 solution (38.00 mg Mn / g solution), 0.8222 g (NH4)2H2(EDTA) solution (401.0 mg EDTA / g solution), 1.4901 g CsOH solution (111.9 mg Cs / g solution), 0.0000 g LiOCOCH3 solution (12.00 mg Li / g solution), 0.4169 g NaOCOCH3 solution (50.00 mg Na / g solution), 0.8144 g (NH4)2SO4 solution (40.00 mg SO4 / g solution), and 5.9702 g NH4ReO4 solution (32.20 g Re / g solution). The resulting catalyst contained 21.41 wt.% Ag, as determined by gravimetric analysis. The target accelerator concentrations for all accelerators are listed in Table 7. Catalyst 52

[0111] According to the vacuum impregnation method presented above, 50.41 g of support G was converted into "catalyst 52". The following amounts were used to prepare the impregnation solution: 165.00 g silver solution (25.69 wt.% Ag), 0.0000 g Mn(NO3)2 solution (38.00 mg Mn / g solution), 0.0000 g (NH4)2H2(EDTA) solution (401.0 mg EDTA / g solution), 1.5414 g CsOH solution (111.9 mg Cs / g solution), 0.0000 g LiOCOCH3 solution (12.00 mg Li / g solution), 0.4314 g NaOCOCH3 solution (50.00 mg Na / g solution), 0.8422 g (NH4)2SO4 solution (40.00 mg SO4 / g solution), and 6.1754 g NH4ReO4 solution (32.20 g Re / g solution). The resulting catalyst contained 21.88 wt.% Ag, as determined by gravimetric analysis. The target accelerator concentrations for all accelerators are listed in Table 7. Catalyst 53

[0112] According to the vacuum impregnation method presented above, 50.35 g of support G was converted into "catalyst 53". The following amounts were used to prepare the impregnation solution: 165.18 g silver solution (25.69 wt.% Ag), 0.6335 g Mn(NO3)2 solution (38.00 mg Mn / g solution), 0.8507 g (NH4)2H2(EDTA) solution (401.0 mg EDTA / g solution), 1.5416 g CsOH solution (111.9 mg Cs / g solution), 0.0000 g LiOCOCH3 solution (12.00 mg Li / g solution), 0.6742 g NaOCOCH3 solution (50.00 mg Na / g solution), 1.1044 g (NH4)2SO4 solution (40.00 mg SO4 / g solution), and 6.1766 g NH4ReO4 solution (32.20 g Re / g solution). The resulting catalyst contained 20.16 wt.% Ag, as determined by gravimetric analysis. The target accelerator concentrations for all accelerators are listed in Table 7. Catalyst 54

[0113] According to the vacuum impregnation method presented above, 50.34 g of support H was converted into "catalyst 54". For the preparation of this catalyst, the silver impregnation solution was prepared by diluting the silver impregnation solution used for catalyst 50 with deionized water. The following amounts were used to prepare the impregnation solution: 165.10 g silver solution (18.00 wt.% Ag), 0.3558 g Mn(NO3)2 solution (38.00 mg Mn / g solution), 0.4771 g (NH4)2H2(EDTA) solution (401.0 mg EDTA / g solution), 0.8036 g CsOH solution (111.9 mg Cs / g solution), 0.4207 g LiOCOCH3 solution (12.00 mg Li / g solution), 0.1264 g NaOCOCH3 solution (50.00 mg Na / g solution), 0.5409 g (NH4)2SO4 solution (40.00 mg SO4 / g solution), and 1.9589 g NH4ReO4 solution (32.20 g Re / g solution). The resulting catalyst contained 16.18 wt.% Ag, as determined by gravimetric analysis. The target accelerator concentrations for all accelerators are listed in Table 7. Catalyst 55

[0114] According to the vacuum impregnation method presented above, 50.13 g of support H was converted into "catalyst 55". For the preparation of this catalyst, the silver impregnation solution was prepared by diluting the silver impregnation solution used for catalyst 50 with deionized water. The following amounts were used to prepare the impregnation solution: 165.10 g silver solution (20.18 wt.% Ag), 0.3576 g Mn(NO3)2 solution (38.00 mg Mn / g solution), 0.4798 g (NH4)2H2(EDTA) solution (401.0 mg EDTA / g solution), 0.8080 g CsOH solution (111.9 mg Cs / g solution), 0.4228 g LiOCOCH3 solution (12.00 mg Li / g solution), 0.1263 g NaOCOCH3 solution (50.00 mg Na / g solution), 0.5438 g (NH4)2SO4 solution (40.00 mg SO4 / g solution), and 1.9690 g NH4ReO4 solution (32.20 g Re / g solution). The resulting catalyst contained 18.36 wt.% Ag, as determined by gravimetric analysis. The target accelerator concentrations for all accelerators are listed in Table 7. Catalyst 56

[0115] According to the vacuum impregnation method presented above, 50.35 g of support H was converted into "catalyst 56". For the preparation of this catalyst, the silver impregnation solution was prepared by diluting the silver impregnation solution used for catalyst 50 with deionized water. The following amounts were used to prepare the impregnation solution: 164.90 g silver solution (18.00 wt.% Ag), 0.5464 g Mn(NO3)2 solution (38.00 mg Mn / g solution), 0.7333 g (NH4)2H2(EDTA) solution (401.0 mg EDTA / g solution), 1.4664 g CsOH solution (111.9 mg Cs / g solution), 2.2263 g LiOCOCH3 solution (12.00 mg Li / g solution), 0.4117 g NaOCOCH3 solution (50.00 mg Na / g solution), 0.8033 g (NH4)2SO4 solution (40.00 mg SO4 / g solution), and 5.8757 g NH4ReO4 solution (32.20 g Re / g solution). The resulting catalyst contained 15.79 wt.% (i.e., 16 wt.% rounded to the nearest integer) Ag, as determined by gravimetric analysis. Target accelerator concentrations for all accelerators are listed in Table 7. Catalyst 57

[0116] According to the vacuum impregnation method presented above, 50.22 g of support H was converted into "catalyst 57". For the preparation of this catalyst, the silver impregnation solution was prepared by diluting the silver impregnation solution used for catalyst 50 with deionized water. The following amounts were used to prepare the impregnation solution: 165.05 g silver solution (20.18 wt.% Ag), 0.5712 g Mn(NO3)2 solution (38.00 mg Mn / g solution), 0.7661 g (NH4)2H2(EDTA) solution (401.0 mg EDTA / g solution), 1.5326 g CsOH solution (111.9 mg Cs / g solution), 2.3264 g LiOCOCH3 solution (12.00 mg Li / g solution), 0.4297 g NaOCOCH3 solution (50.00 mg Na / g solution), 0.8394 g (NH4)2SO4 solution (40.00 mg SO4 / g solution), and 6.1408 g NH4ReO4 solution (32.20 g Re / g solution). The resulting catalyst contained 17.92 wt.% Ag, as determined by gravimetric analysis. Target accelerator concentrations for all accelerators are listed in Table 7. [Simplified Explanation of the Diagram]

[0012] [Figure 1] is a graph depicting the selectivity and activity of catalysts 11-45. [Figure 2] is a graph depicting the selectivity and activity of catalysts 46-57.

Claims

1. A silver catalyst supported on an alumina-containing support comprising more than about 80 wt% α-alumina and less than about 30 wt% acid-leachable alkali metal, wherein the weight percentage of alumina and the concentration of the acid-leachable alkali metal are calculated based on the weight of the support, wherein the acid-leachable alkali metal is selected from lithium, sodium, potassium, and mixtures thereof, wherein the support has been deposited with: (A) silver, in an amount of 16 wt% to 25 wt% based on the weight of the catalyst; and (B) a solid promoter encapsulation comprising cesium, sodium, sulfate, rhenium, and optionally lithium, wherein the amount of such promoter is expressed in millimoles of promoter per kilogram of catalyst, and the amount of such promoter in the solid promoter encapsulation deposited on the catalyst is such that: CCs / Q is in the range of 3.1 to 8.7 mmol / kg catalyst; CNa / Q is in the range of 0.5 to 7.

5. Within the range of mmol / kg catalyst; CS / Q within the range of 0.3 to 3.2 mmol / kg catalyst; CRe / Q within the range of 2.4 to 6.9 mmol / kg catalyst; and CLi / Q within the range of 0 to 35 mmol / kg catalyst; and F1 / Q in the range of 0.3 to 5.2 mmol / kg catalyst; and F2 / Q in the range of -5.1 to 6.3 mmol / kg catalyst; Where Q is a unitless scaling factor, equal to the surface area of ​​the alumina-containing support before silver and promoter deposition, expressed in square meters per gram divided by one square meter per gram. F1 and F2 are defined by the following equations: F1 = CCs + 0.032·CLi + 0.47·CNa - (0.72·CS + 0.94·CRe); F2 = CCs - 0.24·CLi - 0.27·CNa + 0.3·CS; where CCs, CLi, CNa, CS, and CRe are the amounts of cesium, lithium, sodium, sulfate, and rhenium, respectively, deposited on the support in mmol of promoter per kg of catalyst.

2. The catalyst of claim 1, wherein manganese is further deposited on the support, the amount of manganese being 20 ppm to 300 ppm by weight of the catalyst.

3. The catalyst of claim 1 or 2, wherein the amount of cesium deposited on the catalyst is such that CCs / Q is in the range of 4.2 to 7.8 mmol / kg catalyst.

4. The catalyst of any of the preceding claims, wherein the amount of lithium deposited on the catalyst is such that CLi / Q is in the range of 6 to 30 mmol / kg catalyst.

5. The catalyst of any of the preceding claims, wherein the amount of sodium deposited on the catalyst is such that CNa / Q is in the range of 1.2 to 7.5 mmol / kg catalyst.

6. The catalyst of any of the preceding claims, wherein the amount of rhenium deposited on the catalyst is such that CRe / Q is in the range of 3.0 to 6.8 mmol / kg catalyst.

7. The catalyst of any of the preceding claims, wherein the amount of promoter deposited on the catalyst is such that F1 / Q is in the range of 1.5 to 4.1 mmol / kg catalyst.

8. The catalyst of claim 7, wherein the amount of promoter deposited on the catalyst is such that F1 / Q is in the range of 1.9 to 3.7 mmol / kg catalyst.

9. The catalyst of any of the preceding claims, wherein the amount of promoter deposited on the catalyst is such that F2 / Q is in the range of -2.5 to 3.5 mmol / kg catalyst.

10. The catalyst of claim 9, wherein the amount of promoter deposited on the catalyst is such that F2 / Q is in the range of -1.8 to 2.7 mmol / kg catalyst.

11. The catalyst of claim 1 or 2, wherein the amount of promoter in the solid promoter encapsulation deposited on the catalyst is such that: CCs / Q is in the range of 4.7 to 7.3 mmol / kg catalyst; and CLI / Q is in the range of 10 to 26 mmol / kg catalyst; and CNa / Q is in the range of 2.5 to 7.5 mmol / kg catalyst; and CRe / Q is in the range of 3.3 to 6.7 mmol / kg catalyst; and wherein F1 / Q is in the range of 1.9 to 3.7 mmol / kg catalyst; and F2 / Q is in the range of -1.8 to 2.7 mmol / kg catalyst.

12. The catalyst of any of the preceding claims, wherein the catalyst is prepared using a calcination step performed at a temperature in the range of 480°C to 550°C.

13. The catalyst of claim 12, wherein the calcination is carried out on a calcination belt, wherein the catalyst is sustained for no more than 5 minutes in a hot zone at a temperature in the range of 480°C to 550°C.

14. The catalyst of any of the preceding claims, wherein the alumina-containing support has a surface area in the range of 0.7 m² / g to 1.5 m² / g.

15. Use of a catalyst as claimed in any of the preceding claims in the manufacture of ethylene oxide.

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