JP6454891B2 - Support for ethylene epoxidation catalyst, ethylene epoxidation catalyst, and method for vapor phase conversion of ethylene to ethylene oxide - Google Patents

Description

The present invention relates generally to catalysts useful for the epoxidation of olefins to olefin oxides, and more particularly to supports for such catalysts. The present invention also relates to a method for gas phase conversion of ethylene to ethylene oxide.

  As is known in the art, a high selectivity catalyst (HSC) for ethylene epoxidation has a higher selection value than a high activity catalyst (HAC) used for the same purpose. The catalyst which has. Both types of catalysts contain silver as the active catalyst component on a refractory support (ie, support). Usually, one or more types of cocatalysts are included in the catalyst to improve or adjust catalytic properties such as selectivity.

  In general, HSC achieves higher selectivity (usually 87 mol% or more) by mixing rhenium as a promoter. One or more additional promoters typically selected from alkali metals (eg cesium), alkaline earth metals, transition metals (eg tungsten compounds) and main group metals (eg sulfur and / or halide compounds) Is also included.

  There are also catalysts for ethylene epoxidation that have a selection value that exceeds HAC, but that typically cannot have a selection value associated with HSC. This type of catalyst can be considered to be in the class of HSCs, or it can be considered to belong to another class, for example, “intermediate selective catalyst” or “Medium Selectivity Catalyst”. This type of catalyst usually exhibits a selectivity of 83 mol% or more and 87 mol% or less.

  In contrast to HSC and MSC, HAC is generally a catalyst for epoxidation of ethylene that does not contain rhenium and therefore does not provide a selection value like HSC and MSC. Normally, HAC contains cesium (Cs) as the only promoter.

Efforts have been made for many years to improve the activity and selectivity of ethylene oxidation catalysts. Most of these efforts are focused on improving the composition and physical properties of the support (usually alumina), particularly the surface area or pore size distribution of the support. For example, US Pat. No. 4,226,782, US Pat. No. 4,242,235, US Pat. No. 5,266,548, US Pat. No. 5,380,697, US Pat. No. 5,395,812 , US Pat. No. 5,597,773, US Pat. No. 5,831,037, and US Pat. No. 6,831,037, and US Patent Application Publication No. 2004 / 0110973A1 and US Patent Application Publication No. See 2005 / 0096219A1.
[Prior art documents]
[Patent Literature]
U.S. Pat. No. 4,226,782 U.S. Pat. No. 4,242,235 US Pat. No. 5,266,548 US Pat. No. 5,380,697 US Pat. No. 5,395,812 US Pat. No. 5,597,773 US Pat. No. 5,831,037 US Pat. No. 6,831,037 US Patent Application Publication No. 2004 / 0110973A1 US Patent Application Publication No. 2005 / 0096219A1

  Larger support surface areas are known to improve catalyst activity, but high surface areas are usually achieved by simultaneously increasing the pore volume distribution of small pores (ie, sizes typically less than 1 micron). To do. On the other hand, increasing the amount of small pores adversely affects the maximum achievable selectivity of the catalyst. Similarly, attempts to improve selectivity by reducing the volume distribution of small pores have the effect of reducing the surface area of the catalyst, resulting in a decrease in catalyst activity. Thus, the long-standing problem found in the field of catalysts for ethylene oxide, where improved catalyst activity adversely affects catalyst selectivity, as well as improved selectivity adversely affects activity, is an unresolved issue. It remains.

  Accordingly, there remains a need in the art to improve catalyst activity without adversely affecting catalyst selectivity, and at the same time improving. There are significant advantages to achieving this in a simple and cost effective manner that can be easily incorporated into existing process designs.

In one embodiment, the present invention relates to a support for an ethylene epoxidation catalyst. The carrier includes an alumina component containing a first portion of alumina particles having a particle size of 2 μm or more and 6 μm or less and a second portion of alumina particles having a particle size of less than 2 μm.
As a modification of the one embodiment, a first portion of alumina particles having an average primary particle size (D50) of 2 μm or more and 6 μm or less and a second portion of alumina particles having an average primary particle size (D50) of 1 μm or less. The mass ratio of the first part and the second part is 90:10 to 75:25, and further includes an amount of mullite that enhances the stability.

  In a specific embodiment, the support includes an alumina component containing a first portion of alumina particles having a particle size of 3 μm or more and 6 μm or less and a second portion of alumina particles having a particle size of 2 μm or less.

  By including a combination of the aforementioned large and small carrier particles, the surface area of the carrier can be adjusted independently of the change in surface area due to the pore size distribution of the carrier particles. For this reason, a sufficiently large surface area of the support (ie, adequately increasing the catalytic activity) without increasing the pore volume distribution of small pore sizes (generally less than 1 micron) to the point where it adversely affects selectivity. Sufficient surface area) can be achieved. Accordingly, the present invention advantageously provides a support that can be used to make an ethylene oxidation catalyst having increased catalytic activity and maintenance or improved selectivity.

  The present invention also provides a catalytic amount of silver deposited on and / or within the support, and preferably a promoter amount of rhenium. In addition, it is directed to an ethylene oxidation (ie, epoxidation) catalyst comprising the above-described support.

  The present invention is also directed to a method for vapor phase conversion from ethylene to ethylene oxide (EO) in the presence of oxygen. The method includes reacting a reaction mixture comprising ethylene and oxygen in the presence of the ethylene epoxidation catalyst described above.

  In one aspect, the present invention is directed to an improved support (ie, support) for ethylene epoxidation catalysts. The support comprises an alumina component comprising a suitably adjusted large particle size component (ie coarse component) and a small particle size component (ie micro component), as further described below, and the resulting epoxidation catalyst In addition, it provides enhanced activity while maintaining or improving selectivity, or conversely, improved selectivity while maintaining or improving activity.

  The alumina component preferably includes a first portion (coarse component) of alumina particles having a particle size of 2 μm or more and 6 μm or less and a second portion (microcomponent) of alumina particles having a particle size of less than 2 μm. In different embodiments, the particle size of the first portion of alumina particles is, for example, 2 μm, 2.1 μm, 2.2 μm, 2.3 μm, 2.4 μm, 2.5 μm, 2.6 μm, 2.7 μm, 2.8 μm, 2.9 μm, 3 μm, 3.1 μm, 3.2 μm, 3.3 μm, 3.4 μm, 3.5 μm, 3.6 μm, 3.7 μm, 3.8 μm, 3.9 μm, 4 μm, 4. 1 μm, 4.2 μm, 4.3 μm, 4.4 μm, 4.5 μm, 4.6 μm, 4.7 μm, 4.8 μm, 4.9 μm, 5 μm, 5.1 μm, 5.2 μm, 5.3 μm, 5. 4 μm, 5.5 μm, 5.6 μm, 5.7 μm, 5.8 μm, 5.9 μm or 6 μm, or a specific range defined by any two of these numbers (eg, 2-3 μm, 2-2 4 μm, 2-5 μm, 3-5 μm, 3-5.5 μm, 3-4 μm, 4 ˜6 μm or 5-6 μm). In different embodiments, the particle size of the second portion of alumina particles is, for example, 1.9 μm, 1.8 μm, 1.7 μm, 1.6 μm, 1.5 μm, 1.4 μm, 1.3 μm, 1. 2 μm, 1.1 μm, 1 μm, 0.9 μm, 0.8 μm, 0.7 μm, 0.6 μm, 0.5 μm, 0.4 μm, 0.3 μm, 0.2 μm or 0.1 μm or less, or of these A specific range defined by any two numerical values (for example, 0.1 to 1.8 μm, 0.1 to 1.5 μm, 0.1 to 1 μm, 0.1 to 0.8 μm, 0.1 to 0) .6 μm, 0.2 to 1.8 μm, 0.2 to 1.5 μm, 0.2 to 1 μm, 0.2 to 0.8 μm, 0.2 to 0.6 μm, 0.3 to 1.8 μm, 0 .3 to 1.5 μm, 0.3 to 1 μm, 0.3 to 0.8 μm, 0.3 to 0.6 μm, 0.4 to 1.8 μm, 0.4 -1.5 μm, 0.4-1 μm, 0.4-0.8 μm, 0.4-0.6 μm, 0.5-1.8 μm, 0.5-1.5 μm, 0.5-1 μm, 0 .5 to 0.8 μm, 0.6 to 1.8 μm, 0.6 to 1.5 μm, 0.6 to 1 μm, 0.6 to 0.8 μm, 0.7 to 1.8 μm, 0.7 to 1 .5 μm, 0.7-1 μm, 0.8-1.8 μm, 0.8-1.5 μm, 0.8-1 μm, 0.9-1.8 μm, 0.9-1.5 μm, 1-1 .8 μm and 1 to 1.5 μm).

  In some embodiments, a first portion of alumina particles having a particle size of 3 μm or more and 6 μm or less and a second portion of alumina particles having a particle size of 2 μm or less are included. In different embodiments, the particle size of the first portion of alumina particles is, for example, 3 μm, 3.1 μm, 3.2 μm, 3.3 μm, 3.4 μm, 3.5 μm, 3.6 μm, 3.7 μm, 3.8 μm, 3.9 μm, 4 μm, 4.1 μm, 4.2 μm, 4.3 μm, 4.4 μm, 4.5 μm, 4.6 μm, 4.7 μm, 4.8 μm, 4.9 μm, 5 μm, 5. 1 μm, 5.2 μm, 5.3 μm, 5.4 μm, 5.5 μm, 5.6 μm, 5.7 μm, 5.8 μm, 5.9 μm or 6 μm, or defined by any two of these numbers A specific range (for example, 3 to 5 μm, 3 to 5.5 μm, 3 to 4 μm, 4 to 6 μm, or 5 to 6 μm) can be set. In different embodiments, the particle size of the second portion of alumina particles is, for example, 2 μm, 1.9 μm, 1.8 μm, 1.7 μm, 1.6 μm, 1.5 μm, 1.4 μm, 1.3 μm, 1.2 μm, 1.1 μm, 1 μm, 0.9 μm, 0.8 μm, 0.7 μm, 0.6 μm, 0.5 μm, 0.4 μm, 0.3 μm, 0.2 μm or 0.1 μm or less, or these Specific ranges defined by any two numerical values (e.g., 0.1 to 2 [mu] m, 0.1 to 1.5 [mu] m, 0.1 to 1 [mu] m, 0.1 to 0.8 [mu] m, 0.1 to 0) .6 μm, 0.2-2 μm, 0.2-1.5 μm, 0.2-1 μm, 0.2-0.8 μm, 0.2-0.6 μm, 0.3-2 μm, 0.3-1 0.5 μm, 0.3-1 μm, 0.3-0.8 μm, 0.3-0.6 μm, 0.4-2 μm, 0.4-1.5 m, 0.4~1μm, it can be 0.4~0.8μm or 0.4-0.6).

  Said particle size can be said to be the diameter when the particles are spherical or nearly spherical. If the particles depart from a substantially spherical shape, the above particle size should be based on the equivalent diameter of the particles. As known in the art, the term “equivalent diameter” refers to the size of an irregularly shaped object by expressing the size of the object in terms of the diameter of a sphere having the same volume as the irregularly shaped object. Used to represent. The average particle size, referred to herein as “D50”, was determined as measured using a particle size analyzer (Nikkiso Co., Ltd., laser diffraction / scattering type, MT3300 or HRA (X100)). It represents the particle size with an equal spherical equivalent volume of particles larger and smaller than the diameter.

  In some embodiments, the alumina particles are crystalline. Crystalline particles can include single crystal or polycrystalline particles. In another embodiment, the alumina particles are amorphous, i.e. amorphous.

Coarse alumina particles are typically produced by firing aluminum hydroxide by the Bayer process. Generally, the Bayer process produces granulated alumina particles as a result. A comprehensive review of the buyer method can be found, for example, in Kirk-Othmer Encyclopedia of Chemical Technology, Fourth Edition, Vol. 2, John Wiley & Sons, (c) 1992, pp. 252-261. Due to granulation, coarse alumina particles generally have a primary particle size (ie, individual particles or crystal grains contained in the granulation), as well as exhibiting the size of the granulation. Has a secondary particle size. For example, coarse alumina particles can be composed of granulates having an average (secondary) particle size (eg, D ₅₀ ) of 40 μm, where each granule is an average (primary) of 3-5 μm. It is composed of primary particles having a particle size. In different embodiments, the coarse alumina particles can have a secondary particle size of, for example, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, or 120 μm.

  In general, fine alumina particles are produced by grinding (eg, crushing) large, typically granulated particles. Thus, the fine alumina particles are typically in a non-granulated form.

  At least a first portion of alumina particles (ie large particles of 2-6 μm) and a second portion of alumina particles (ie small particles of 2 μm or less) need to be present in the support, ie alumina particles. The first portion of the alumina particles does not have an amount of 100 mass percent (wt%), and the second portion of the alumina particles does not have an amount of 100 wt% (the aforementioned wt% represents the alumina component in the support). The ratio of the mass to the mass). In different embodiments, the first or second portion of alumina particles is at least 1 wt%, 2 wt%, 5 wt%, 10 wt%, 20 wt%, 25 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%. , 70 wt%, 80 wt%, 90 wt%, 95 wt%, 98 wt% or 99 wt%, or an amount within the mass percent (wt%) range defined by any of the above numbers. In one embodiment, the alumina component includes only a first portion and a second portion of alumina particles, and if the wt% of one portion of the alumina particles is A, the wt% of the other portion is necessarily 100-A. In another embodiment, the alumina component may comprise other portions of alumina particles that do not have a particle size that falls within the broad range described for the first and second portions of alumina particles, as described above (e.g., third 1) or more. One or more other parts of the alumina particles (ie, outside the particle size range of the first and second parts of the alumina particles) are 50 wt%, 40 wt%, 30 wt%, 25 wt%, 20 wt%, 15 wt% Preferably, it has a wt% of less than 10 wt%, 5 wt%, 2 wt%, 1 wt%, 0.5 wt%, 0.2 wt% or 0.1 wt%.

  The coarse and fine alumina particles can be in any suitable mass ratio. For example, in different embodiments, the support is 95: 5, 90:10, 85:15, 80:20, 75:25, 70:30, 65:35, 60:40, 55:45, 50: Having a coarse to fine alumina mass ratio of 50, 45:55, 40:60, 35:65, 30:70, 25:75, 20:80, 15:85, 10:90 or 5:95; Alternatively, it can be a mass ratio within the range defined by any two of the above ratios.

In some embodiments, a minor component (eg, an amount of 1 wt%, 0.5 wt%, 0.1 wt%, or 0.05 wt% or less) is included without considering the effect on the wt% of the support. Except for this, the support is composed only of alumina, in particular composed only of coarse alumina components and fine alumina components. In another embodiment, components other than alumina are not present in trace amounts, typically at least 1 wt%. In such an embodiment, the amount of additional component (X) is determined by subtracting X from either the coarse alumina component and / or the fine alumina component in the alumina particle ratio (coarse to fine mass ratio). Can be included in any ratio of the general coarse to fine mass ratio, provided that X does not replace either the coarse alumina component and / or the fine alumina component (ie, the coarse alumina component and the fine alumina component Both components of the alumina component are present), typically except that the amount of X does not exceed the total amount of alumina in the support or the amount of individual alumina (more generally less than those amounts). . For example, the amount of the additional component X is represented by the following formula: (80-X): 20: X, 80: (20-X): X, or (80-X ₁ ) :( 20-X ₂ ): X Here, the sum of X ₁ and X ₂ can be incorporated into the coarse to minute mass ratio of 80:20 alumina particles by any of X. In any of the above exemplary coarse alumina component: fine alumina component: X component ratios, the amount of X is, for example, 1, 2, 3, 4, 5, 10, 15, 20, 25, or 30. Or within a range defined by any two of these numbers.

  The alumina particles are preferably composed of any of the heat resistant alumina components known in the art for use in ethylene oxidation catalysts. Preferably, the alumina is α-alumina. The α-alumina used in the carrier of the present invention is very high in purity, that is, preferably about 95 wt% or more, and more preferably 98 wt% or more α-alumina. Preferably, the α-alumina is low soda alumina or low soda reactive alumina. As used herein, the term “reactive alumina” generally refers to α-alumina that has good sinterability and a very fine particle size, ie, generally 2 microns or less. In general, “low soda alumina” materials contain less than 0.1% sodium. Alternatively, or in addition, “low soda alumina” may mean an alumina material with 0.1 mg or less sodium. Good sinterability is generally obtained with a particle size of 2 microns or less.

  The remaining components may be alumina, silica, other phases (s) of alkali metal oxides (eg, sodium oxide), and trace amounts of other metal-containing and / or non-metal-containing additives or impurities. Suitable alumina components are, for example, manufactured and / or marketed by Noritake Company Limited (Nagoya, Japan) and NorPro (Akron, Ohio).

The support can optionally include an amount of mullite (an example of additional component X) that enhances stability to provide an epoxidation catalyst with improved stability and / or selectivity. As used herein, “mullite” (also known as “porcelainite”) is at least about 40 mol%, usually about 80 mol% or less, mixed as a solid solution with the SiO ₂ phase. Refers to an aluminum silicate mineral having an Al ₂ O ₃ component present at a concentration of. More generally, mullite contains an Al ₂ O ₃ component at a concentration of 60 ± 5 mol%, and is therefore generally represented by the formula 3Al ₂ O ₃ · 2SiO ₂ (ie, Al ₆ Si ₂ O ₁₃ ). it can.

Because of the scarce natural resources of mullite, most commercial sources of mullite are synthetic materials. Various synthetic methods for mullite production are known in the art. In one embodiment, the mullite used contains components other than the alumina and silica components described above, apart from one or more components that may be present in trace amounts (eg, less than 0.1 mol% or less than mass%). Not done. In another embodiment, the mullite used can include one or more additional ingredients. For example, a small amount (usually about 1.0 mol% or less by mass) of sodium oxide (Na ₂ O) can be included. Other components such as zirconia (Zr ₂ O) and silicon carbide (SiC) can also be included, for example, to increase fracture toughness. Many other metal oxides can also be included to alter the properties of mullite.

  The amount of mullite that enhances stability is typically at least about 0.5 wt% to about 20 wt% mullite relative to the total mass of the support. In one embodiment, the mullite is at least about 1 wt% up to about 20 wt%, 15 wt%, 12 wt%, 10 wt%, 8 wt%, 6 wt%, 5 wt%, 4 wt%, 3 wt%, or the total mass of the support. Present in the carrier at a concentration of 2 wt% or less. In another embodiment, the mullite is at a concentration of at least about 3 wt% up to about 20 wt%, 15 wt%, 12 wt%, 10 wt%, 8 wt%, 6 wt%, 5 wt% or 4 wt% relative to the total mass of the support. Present in the carrier. In yet another embodiment, mullite is present in the support at a concentration of at least about 5 wt% up to about 20 wt%, 15 wt%, 12 wt%, 10 wt%, 8 wt%, 7 wt% or 6 wt% relative to the total mass of the support. Exists. In yet another embodiment, mullite is present in the support at a concentration of at least about 7 wt% up to about 20 wt%, 15 wt%, 12 wt%, 10 wt%, 9 wt%, or 8 wt% relative to the total weight of the support. To do. In yet another embodiment, the mullite is about 0.5-15 wt%, 0.5-12 wt%, 0.5-10 wt%, 0.5-8 wt%, 0.5- 0.5% relative to the total mass of the support. 6 wt%, 0.5-5 wt%, 0.5-3 wt%, 0.5-2 wt%, 8-20 wt%, 9-20 wt%, 10-20 wt%, 8-15 wt%, 9-15 wt% or 10 It can be present in the support within a concentration range of ˜15 wt%.

  In one embodiment, the outer surface of the bulk alumina support or the alumina particles themselves is covered with mullite. The outer surface may be covered together with or under the surface of the carrier that also contains mullite, or there may be either no surface or inside that contains mullite. In another embodiment, the outer surface of the alumina support or the alumina particles themselves are not covered with mullite, but either below the surface of the support or the inner region contains mullite.

  In general, suitable catalyst supports are prepared by a method in which alumina of various particle sizes and any mullite particles are combined with a binder. For example, a suitable catalyst support may be a mixture of an alumina component, a mullite component, a solvent such as water, a temporary binder or a combustion material, a persistent binder and / or a porosity control agent, and the mixture is It can be prepared by firing (ie, calcining) by methods well known in the art.

  Temporary binders or combustion materials include cellulose, for example substituted celluloses such as methylcellulose, ethylcellulose and carboxyethylcellulose, stearic acids (such as organic stearates such as methyl stearate or ethyl), waxes, granular polyolefins (for example , Polyethylene and polypropylene), and walnut shell powder, which can be decomposed at the temperature used. The binder is responsible for imparting the porosity of the support material. Combustion materials are primarily used to ensure that the porous structure is maintained during the premature period (ie, the green stage) during which the mixture can be formed into particles by a forming or extrusion process. Combustion material is essentially all removed during calcination to produce the finished carrier.

  The carrier of the present invention is preferably prepared with a sufficient amount of binding material to substantially prevent the formation of crystalline silica compounds. Persistent binders include, for example, clay-like inorganic materials such as silica and alkali metal compounds. A convenient binder that may be included in the alumina particles is a mixture of boehmite, ammonia stabilized silica sol and soluble sodium salt.

The formed paste is extruded or molded into a desired shape, and is usually fired (calcined) at a temperature of about 1200 ° C. to about 1600 ° C. to form a carrier. In different embodiments, the firing temperature is, for example, 1200 ° C., 1250 ° C., 1300 ° C., 1350 ° C., 1400 ° C., 1450 ° C., 1500 ° C., 1550 ° C., 1600 ° C. or 1650 ° C., or any two of the above temperatures It may be within a range defined by two temperatures. In embodiments where the particles are formed by extrusion, it may be desirable to include a conventional extrusion aid. Generally, as described in U.S. Patent Application Publication No. 2006/0252643 A1, the treatment is performed by immersing the support in an alkaline hydroxide such as sodium hydroxide or potassium hydroxide, or an acid solution such as HNO _3. The performance of the carrier is increased. After the treatment, it is preferable that the carrier is washed with water or the like to remove unreacted dissolved substances and the treatment solution, and optionally dried.

The carrier according to the invention is preferably porous and usually has a BET surface area of at most 20 m ² / g. Range of BET surface area is more typically from about 0.1 to about ^{10 m} 2 / g, and more typically 1 to 5 m ² / g. In another embodiment, the carrier of the present invention is from about 0.3 m ² / g to about ^3m 2 / g, preferably from about 0.6 m ² / g to about 2.5 m ² / g, more preferably from about 0. It is characterized by having a BET surface area of 7m ² / g to about 2.0 m ² / g. The BET surface area described herein can be measured by any suitable method, as described in Brunauer, S., et al., J. Am. Chem. Soc., 60, 309-16 (1938). More preferably, it is obtained by a method. The water absorption value of the finished support is generally in the range of about 0.2 cc / g to about 0.8 cc / g, more typically about 0.25 cc / g to about 0.6 cc / g.

The carrier can have any suitable surface area as long as the surface area does not substantially reduce the ability of the carrier to function with the intended utility. Surface area, for example, at least about ^{0.7m 2 /g,0.75m 2 /g,0.8m 2 /g,0.85m 2} /g,0.9m 2 /g,0.95m 2 / g, ^{1.0m 2 /g,1.05m 2 /g,1.1m 2 /g,1.2m 2} /g,1.3m 2 /g,1.4m 2 /g,1.5m 2 / g, 1 ^{.6m 2 /g,1.7m 2 /g,1.8m 2 /g,1.9m 2} /g,2.0m 2 /g,2.5m 2 /g,3.0m 2 / g, 3. ^{5m 2 /g,4.0m 2 /g,4.5m 2 /g,5.0m 2} /g,5.5m 2 /g,6.0m 2 /g,6.5m 2 /g,7.0m ^{2 /g,7.5m 2 /g,8.0m 2 /g,8.5m 2 /g,9.0m} 2 /g,9.5m 2 / g, 10m 2 / g, 11m 2 / g, 12m ^{2 / g, 15m 2 / g} , or, 20 m ² / g or less, or the number of the It can be in a range defined by any two numbers of the.

  The support may have any pore diameter distribution where appropriate. As used herein, “pore diameter” is used interchangeably with “pore diameter”. The pore volume (and pore size distribution) described herein can be measured by any suitable method, for example, Drake and Ritter, Ind. Eng. Chem. Anal. Ed., 17, 787 More preferably, it is obtained by a conventional mercury porosimeter method as described in (1945).

  Preferably, the pore diameter is at least about 0.01 micron (0.01 μm), more typically at least about 0.1 μm. In yet another embodiment, the pore diameter is at least about 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1 μm, .2 μm, 1.4 μm, 1.6 μm or 1.8 μm. In different embodiments, the pore diameter is about 2.0 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm. 8.5 μm, 9 μm, 9.5 μm, 10 μm, or 10.5 μm or less. Any range derived from the foregoing minimum and maximum exemplary values is also appropriate herein. In certain embodiments, the average pore diameter of the support is 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8. 1.9 or 2.0, or the average pore diameter within the range defined by any two of the above numbers.

  In different embodiments, the proportion of pores (e.g. relative to the pore volume) with a size of 0.5 [mu] m, 1 [mu] m, 1.5 [mu] m or 2 [mu] m or less, or within those ranges (e.g. 1-2 [mu] m). Is 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, 5%, 2% or 1% or less, or It is within the range defined by any two of the numerical values. In another embodiment, no more than 20%, 15%, 10%, 5%, 2% or 1% of the pores are larger than 2 μm. In certain embodiments, at least 50%, 60%, 70%, 80%, 90%, 95%, 98%, 99% or 100% of the pores are 0.1-6 μm, 0.5-6 μm, 1-6 μm, 1.5-6 μm, 2-6 μm, 3-6 μm, 0.1-5 μm, 0.5-5 μm, 1-5 μm, 1.5-5 μm, 2-5 μm, 3-5 μm,. 1-4 μm, 0.5-4 μm, 1-4 μm, 1.5-4 μm, 2-4 μm, 0.1-3 μm, 0.5-3 μm, 1-3 μm, 1.5-3 μm, 0.1 The size is 2.5 μm, 0.5 to 2.5 μm, 1 to 2.5 μm, 0.1 to 2 μm, 0.5 to 2 μm, or 1 to 2 μm.

  Usually the support has a pore size distribution (characterized by the presence of one or more pore size peak concentrations relative to the number of pore distribution plots, ie, the presence of one or more maximum pore size values (with a slope of approximately zero). For example, it is within the range described above. The maximum concentration of pore diameter is also referred to herein as peak pore diameter, peak pore volume or peak pore concentration. In a preferred embodiment, the pore size distribution is characterized by the presence of a peak pore size of 2 μm or less. In different embodiments, the pore size distribution is about 2 μm, 1.8 μm, 1.6 μm, 1.4 μm, 1.2 μm, 1.0 μm, 0.8 μm, 0.7 μm, 0.6 μm, 0.5 μm, 0 4 μm, 0.3 μm, 0.2 μm or 0.1 μm, or a peak pore diameter within a specific range defined by any two of the above numbers.

  Furthermore, each pore size distribution can be characterized by a single average pore size (average pore diameter) value. Therefore, the average pore size value of the pore size distribution inevitably corresponds to the pore size range that results in the indicated average pore size value. Any of the pore sizes exemplified above are understood to mean alternatively average (ie, standard or weighted average) pore sizes.

  The support can have any suitable total pore volume as long as the total pore volume does not substantially reduce the ability of the support to function with the intended utility. The total pore volume is, for example, at least about 0.2 mL / g, 0.25 mL / g, 0.3 mL / g, 0.35 mL / g, 0.40 mL / g, or 0.45 mL / g or less, or , Can be within a range defined by any two of the above numbers. The porosity (eg, apparent porosity) is related to the total pore volume. The porosity can be, for example, approximately at least 35, 40, 45, 50, 55, or 60% or less, or within a range defined by any two of the aforementioned numerical values.

  In certain embodiments, the support has a multimodal pore size distribution within any of the pore size ranges described above. Multimodal pore size distribution is characterized by the presence of different peak concentrations of pore size (ie, different peak pore sizes) versus the number of pore distribution plots. The different peak pore diameters are preferably within the above pore diameter range. Each peak pore size can be considered to be within its own pore size distribution (mode), ie, the concentration of pore sizes on both sides of the distribution is generally zero (actually or theoretically). The multimodal pore size distribution may be, for example, bimodal, trimodal or higher multimodal. In one embodiment, the different pore size distributions, each having a peak pore size, do not overlap by being separated by portions where the pore concentration is approximately zero (ie, baseline). In another embodiment, the different pore size distributions, each having a peak pore size, overlap because they are not separated by portions where the pore concentration is generally zero.

  In certain embodiments, the difference between the average pore diameter of the first mode of pores and the average pore diameter of the second mode of pores in the multimodal pore size distribution (ie, “average fine The difference in pore diameters ”) is at least about 0.1 μm. In different embodiments, the average pore size difference is at least, for example, 0.2 μm, or 0.3 μm, or 0.4 μm, or 0.5 μm, or 0.6 μm, or 0.7 μm, or 0.8 μm, Or 0.9 μm, or 1.0 μm, or 1.2 μm, or 1.4 μm, or 1.5 μm, or 1.6 μm, or 1.8 μm, or 2.0 μm.

  The carrier of the present invention may have any suitable shape or form. For example, the support is preferably in the form of particles, lumps, granules, rings, spheres, three holes, wagon wheels, cruciform hollow cylinders, etc., of dimensions suitable for use in a fixed bed reactor. Can do.

  The carrier can have any suitable water absorption (rate) as long as the water absorption (rate) does not substantially reduce the ability of the carrier to function with the intended utility. The water absorption (rate) can be, for example, approximately at least 20, 25, 30, 35, 40, or 45% or less, or within a range defined by any two of the aforementioned numerical values.

  The carrier can have any suitable crush strength value as long as the crush strength value does not substantially reduce the ability of the carrier to function with the intended utility. The crushing strength is, for example, approximately or at least 40 Newton (40N), 45N, 50N, 55N, 60N, 65N, 70N, 75N, 80N, 85N, 90N, 95N, 100N, 105N, 110N, 115N or 120N, or Can be within a range defined by any two of the numbers.

  In one embodiment, the support of the present invention basically comprises only alumina or alumina and mullite components, except that trace amounts of other metals or compounds may be present, and other metals or chemicals. Is not included. A trace amount is a sufficiently small amount that the trace species do not significantly affect the function or performance of the catalyst.

  In another embodiment, the support of the present invention comprises one or more cocatalyst species. As used herein, a “promoting amount” of a particular component of a catalyst improves one or more catalytic properties of the catalyst when compared to a catalyst that does not contain that component. Refers to the amount of a component that acts effectively to achieve (ie, an effective amount as a promoter). Examples of catalytic properties include operability (runaway resistance), selectivity, activity, conversion, stability and yield, among others. It will be appreciated by those skilled in the art that one or more individual catalytic properties may be improved by “amount of cocatalyst” while other catalytic properties may be improved, may not be improved, or may be further reduced. If so, understand. It is further understood that different catalyst properties are enhanced by different processing conditions. For example, a catalyst that increases selectivity under certain processing conditions may be processed under different conditions, in which case there is an improvement in activity over selectivity.

  For example, the support of the present invention may contain a promoter amount of alkali metal or a mixture of two or more alkali metals. Suitable alkali metal promoters include, for example, lithium, sodium, potassium, rubidium, cesium or combinations thereof. In many cases, cesium is preferred, and combinations of cesium and other alkali metals are also preferred. The amount of alkali metal is generally in the range of about 10 ppm to about 3000 ppm, more typically about 15 ppm to about 2000 ppm, and more generally, based on the total catalyst mass when expressed in terms of alkali metal. Generally from about 20 ppm to about 1500 ppm, and even more typically from about 50 ppm to about 1000 ppm.

  The support of the present invention may comprise a promoter amount of a Group IIA alkaline earth metal or a mixture of two or more Group IIA alkaline earth metals. Suitable alkaline earth metal promoters include, for example, beryllium, magnesium, calcium, strontium and barium or combinations thereof. As the amount of the alkaline earth metal promoter, the same amount as that of the alkali metal promoter described above is used.

  The support of the present invention may also contain a promoter amount of a main group element or a mixture of two or more main group elements. Suitable main group elements include any of the elements from group IIIA (boron group) to group VIIA (halogen group) of the periodic table. For example, the catalyst can each include a cocatalyst amount of one or more sulfur compounds, one or more phosphorus compounds, one or more boron compounds, one or more halogen-containing compounds, or a combination thereof. In addition to halogen, the catalyst can also contain main group elements in its elemental form.

  The support of the present invention may contain a cocatalytic amount of a transition metal or a mixture of two or more transition metals. Suitable transition metals are, for example, group IIIB (scandium group), group IVB (titanium group), group VB (vanadium group), group VIB (chromium group), group VIIB (manganese group), group VIIIB (iron). , Cobalt, nickel group), group IB (copper group) and group IIB (zinc group) elements, and combinations thereof. More generally, the transition metal is an early transition metal, i.e. from the IIIB, IVB, VB or VIB group, e.g. hafnium, yttrium, molybdenum, tungsten, rhenium, chromium, titanium, zirconium, vanadium. Tantalum and niobium, or a combination thereof.

  The support of the present invention may also contain a promoter amount of a rare earth metal or a mixture of two or more rare earth metals. The rare earth metal contains any element having an atomic number of 57 to 103. Some examples of these elements include lanthanum (La), cerium (Ce), and samarium (Sm).

  Transition metal or rare earth metal promoters, when expressed in terms of metals, are generally present in an amount of from about 0.1 micromole per gram of total catalyst to about 10 micromole per gram, more commonly From about 0.2 micromole per gram to about 5 micromole per gram, more typically from about 0.5 micromole per gram to about 4 micromole per gram.

  Apart from alkali metals, all of these cocatalysts can be in any suitable form including, for example, zero-valent metals or high-valent metal ions.

  Of the promoters described, rhenium (Re) is preferred as a particularly effective promoter for highly selective catalysts for ethylene epoxidation. The rhenium component in the catalyst may be in any form as appropriate, but one or more rhenium-containing compounds (eg, rhenium oxide) or complexes are more common. Rhenium can be present, for example, in an amount from about 0.001 wt% to about 1 wt%. More generally, rhenium, when expressed as rhenium metal, is, for example, from about 0.005 wt% to about 0.5 wt%, and even more typically about wt%, based on the total catalyst weight including the support. It is present in an amount of 0.01 wt% to about 0.05 wt%.

  In another aspect, the present invention is directed to an ethylene epoxidation catalyst produced from the support described above. In order to produce a catalyst, a support having the above properties comprises a catalytically effective amount of silver thereon and / or therein. The catalyst is prepared by impregnating the support with silver ions, compounds, complexes and / or salts dissolved in a suitable solvent sufficient to deposit the silver precursor compound on and / or within the support. For example, rhenium and silver are impregnated and incorporated into the support together with any desired cocatalyst by any conventional method known in the art, such as excess solution impregnation, initial wet impregnation, spray coating, etc. be able to. Usually, the support material is left in contact with the silver-containing solution until a sufficient amount of solution is absorbed by the support. Preferably, the amount of silver-containing solution used to impregnate the support is only that amount necessary to fill the pore volume of the support. By assisting with the application of a vacuum, the silver-containing solution can penetrate into the carrier. Depending on the concentration of the silver component in the solution, a single impregnation or a series of impregnations can be performed with or without intermediate drying. The impregnation process is described, for example, in US Pat. No. 4,761,394, US Pat. No. 4,766,105, US Pat. No. 4,908,343, US Pat. No. 4,908,343, all of which are incorporated herein by reference. US Pat. No. 5,057,481, US Pat. No. 5,187,140, US Pat. No. 5,102,848, US Pat. No. 5,011,807, US Pat. No. 5,099,041 and US Pat. No. 5,407,888. Known processes such as pre-deposition, co-deposition and post-deposition of various promoters can also be utilized.

  Silver compounds useful for impregnation include, for example, silver oxalate, silver nitrate, silver oxide, silver carbonate, silver carboxylate, silver citrate, silver phthalate, silver lactate, silver propionate, silver butyrate and high fatty acid salts and the like Including a combination of The silver solution used for impregnation of the support may contain any suitable solvent. The solvent can be, for example, aqueous, organic, or a combination thereof. The solvent may have any polarity including high polarity, moderate polarity or non-polarity, or substantial or complete non-polarity, as appropriate. Usually, the solvent has sufficient solvating power to solubilize the solution components. Examples of some aqueous solvents include water and water / alcohol mixtures. Examples of some organic solvents include alcohols (eg, alkanols), glycols (eg, alkyl glycols), ketones, aldehydes, amines, tetrahydrofuran, nitrobenzene, nitrotoluene, glymes (eg, glyme, Diglyme and tetraglyme), and combinations thereof, but are not limited thereto. Organic solvents having 1 to about 8 carbon atoms per molecule are preferred.

  A wide variety of complexing or solubilizing agents can be used to solubilize the silver to the desired concentration in the impregnation medium. Useful complexing or solubilizing agents include amines, ammonia, lactic acid and combinations thereof. For example, the amine can be an alkylene diamine having 1 to 5 carbon atoms. In one preferred embodiment, the solution comprises an aqueous solution of silver oxalate and ethylenediamine. The complexing / solubilizing agent may be present in the impregnation solution in an amount of about 0.1 to about 5.0 moles of ethylenediamine per mole of silver, preferably about 0.2 to about 4.0 moles, More preferably from about 0.3 to about 3.0 moles of ethylenediamine per mole of silver.

  The concentration of the silver salt in the solution is usually in the range from about 0.1% by mass to the maximum at which the specific silver salt can be dissolved in the solubilizer used. More typically, the silver salt concentration is about 0.5% to 45% by weight silver, and even more typically about 5 to 35% by weight.

  An ethylene oxide (EO) catalyst contains a catalytically effective amount of metallic silver and catalyzes the synthesis of ethylene and oxygen to ethylene oxide. Silver can be present across the surface and pores of the refractory support. The catalytically effective amount of silver can be, for example, up to about 45% by weight or less of silver expressed as a metal with respect to the total mass of the catalyst including the support. More commonly, the silver content expressed as metal is from about 1% to about 40% based on the total mass of the catalyst. In another embodiment, the silver content is, for example, about 1-35%, 5-35%, 1-30%, 5-30%, 1-25%, 5-25%, 1-20%, 5-20%, 8-40%, 8-35%, 8-30%, 10-40%, 10-35%, 10-25%, 12-40%, 12-35%, 12-30% or It can be 12 to 25%.

  In order to obtain a highly selective catalyst, it is also preferable to include rhenium in the silver-containing catalyst. The rhenium is incorporated in the amount of promoter described above prior to silver deposition (ie, pre-incorporation into the support), simultaneously or after.

  One or more other co-catalyst species can be incorporated into the support prior to, simultaneously with, or after silver deposition (deposition). In a preferred embodiment, the added cocatalyst comprises one or more species selected from Cs, Li, W, F, P, Ga and S. In another preferred embodiment, the added cocatalyst comprises one or more species selected from Cs, Li and S.

  After incorporating silver and any cocatalyst, the impregnated support is removed from the solution and the silver compound is reduced to metallic silver and calcined for a time sufficient to remove volatile decomposition products from the silver-containing support. To do. Calcination is usually carried out at a reaction pressure in the range of about 0.5 to about 35 bar, preferably at a step rate of about 200 ° C. to about 600 ° C., more typically about 200 ° C. to about 500 ° C. It is generally carried out by heating the impregnated support to a temperature in the range of about 250 ° C to about 500 ° C, more typically about 200 ° C or 300 ° C to about 450 ° C. In general, the higher the temperature, the shorter the required firing time. In this field, a wide range of heating times is described for heat treatment of impregnated supports. For example, U.S. Pat. No. 3,563,914, which discloses heating for less than 300 seconds, and U.S. Pat., Which discloses heating for 2-8 hours at a temperature of 100-375 [deg.] C. to reduce the silver salt in the catalyst. See Japanese Patent No. 3,702,259. Here, continuous or stepwise heating may be used.

  During firing, the impregnated support is typically exposed to a gas atmosphere containing an inert gas such as nitrogen. The inert gas may also contain a reducing agent.

  In another aspect, the present invention is directed to a process for the vapor phase production of ethylene oxide by converting ethylene to ethylene oxide in the presence of oxygen using the catalyst described above. Generally, the ethylene oxide production step is carried out in the presence of a catalyst at a temperature ranging from about 180 ° C to about 330 ° C, more typically from about 200 ° C to about 325 ° C, and more typically from about 225 ° C to about 270 ° C. The oxygen-containing gas and ethylene are continuously contacted at a pressure that may vary from approximately atmospheric pressure to approximately 30 atmospheres depending on the desired mass rate and productivity. A pressure in the range of about atmospheric to about 500 psi is commonly used. However, higher pressures may be used within the scope of the present invention. Residence times in large reactors are usually on the order of about 0.1 to about 5 seconds. The usual process for oxidizing ethylene to ethylene oxide involves the gas phase oxidation of ethylene and molecular oxygen in a fixed bed tubular reactor in the presence of the catalyst of the present invention. Conventional commercially available fixed bed ethylene oxidation reactors typically have the shape of a plurality of parallel elongated tubes (within a suitable shell structure). In one embodiment, the tube has an outer diameter of about 0.7-2.7 inches, an inner diameter of 0.5-2.5 inches, a length of 15-45 feet, and is packed with catalyst.

  The catalysts described herein have been shown to be particularly selective catalysts for the oxidation of ethylene and molecular oxygen to ethylene oxide. Conditions for conducting such oxidation reactions in the presence of the catalysts described herein broadly include those described in the prior art. For example, appropriate temperature, pressure, residence time, diluent (eg, nitrogen, carbon dioxide, steam, argon, methane or other saturated hydrocarbons), mitigating agents that control catalysis (eg, 1,2-dichloroethane) , Vinyl chloride or ethyl chloride), the desirability of using a recycle operation to increase the yield of ethylene oxide or sequential conversion in different reactors, and other special conditions that can be selected for the ethylene oxide preparation process Is this. The molecular oxygen used as the reactant can be obtained from conventional sources. Suitable oxygen to be filled may be relatively pure oxygen, a concentrated oxygen stream containing a large amount of oxygen with a small amount of one or more diluents such as nitrogen or argon, or air.

In the production of ethylene oxide, the reactant feed mixture typically contains about 0.5 to about 45% ethylene and about 3 to about 15% oxygen with the balance being nitrogen, carbon dioxide, methane, ethane, argon, and the like. Includes relatively inert materials, including substances. Usually, only a part of ethylene reacts each time it passes over the catalyst. Usually, the unreacted material is subjected to an oxidation reaction after separating the desired ethylene oxide product and removing the appropriate purge stream and carbon dioxide to prevent uncontrolled formation of inert products and / or by-products. Returned to the vessel. By way of example only, the following are conditions that are frequently used in commercially available ethylene oxide reactor units. Gas hourly space velocity (GHSV) 1500-10000 h ⁻¹ , reactor inlet pressure 150-400 psig, coolant temperature 180-315 ° C., oxygen conversion level 10-60%, and ethylene oxide production rate (working speed) per cubic meter of catalyst 100-300 kg of ethylene oxide per hour. Feed composition at the reactor inlet is typically 1-40% ethylene, 3-12% oxygen, 0.3 to 40% of _CO 2, 0 to 3% of the ethane, total concentration 0.3~20ppmv Organic chloride moderator and argon, methane, nitrogen or mixtures thereof as the balance of the feed.

  In another embodiment, the ethylene oxide production method includes the addition of oxidizing gas to the feedstock to increase process efficiency. For example, US Pat. No. 5,112,795 discloses the addition of 5 ppm nitric oxide to a gas feed having the following general composition: 8% oxygen, 30% ethylene, about 5 ppmw. Ethyl chloride and the balance nitrogen.

  The produced ethylene oxide is separated from the reaction product and recovered using methods known in the art. The ethylene oxide process may include a gas recycling process, and after fully or partially removing the ethylene oxide product and by-products, some or nearly all of the reactor exhaust is reintroduced from the reactor inlet. In the recycle mode, the carbon dioxide concentration at the gas inlet of the reactor may be, for example, about 0.3 to about 6% by volume.

  In order to further illustrate the present invention, the following examples are set forth. The scope of the invention is not limited to the examples described herein.

Synthesis of Alumina-Based Porous Support Low Soda Alumina having an average particle size (D50) of 3.2 μm (average aggregated particle (secondary particle) size (D50) of 40 μm, surface area of 0.5 to 1.0 m ² / g) Na ₂ O content less than 0.08%) 72 parts by mass of coarse particles, 18 parts by mass of fine alumina particles having an average particle size (D50) of 0.6 μm (surface area of 5 to 10 m ² / g), and an average particle size (D50) ) Was mixed with 10 parts by mass of a mullite inorganic binder having a size of 10 μm or more and 12 μm or less to obtain an alumina raw material. The particle size distribution of the particles was measured using a particle size analyzer (manufactured by Nikkiso Co., Ltd., laser diffraction scattering type, MT3300 or HRA (X100)).

  20 parts by mass of water is added to 100 parts by mass of the alumina raw material, and 8 parts by mass of an organic forming aid (including an organic binder) together with 2 parts by mass of walnut powder as a pore forming agent. Added. Cellulose aids and wax aids were used as molding aids. The amount of molding aid and water can be adjusted to allow the mixture to be extruded. The resulting mixture was mixed by a kneader and then extruded to obtain a hollow tube molded body having an outer diameter of 8 mm, an inner diameter of 4 mm and a length of 8 mm. The extruded mixture was dried at 60 ° C. to 100 ° C. for 2 hours and placed in a refractory mortar. The mortar consists of a sintered setter fitted with a sintered frame (frame). And the baking process was performed to the extruded mixture using roller hearth kiln. In the firing step, the mortar was exposed to an elevated temperature of 1400 ° C. or higher for 2 hours and held at this temperature for 0.5 hour.

The obtained carrier had a surface area of 0.89 m ² / g, a water absorption of 31.6%, and an apparent porosity of 55%. The total volume of the micropores was found to be 0.32 mL / g. The peak of the pore volume distribution was found to be about 1.2 μm. The pore volume ratio with respect to the total pore volume of pores having a diameter of 1 μm or less was 33.1%. For pores with a diameter greater than 1 μm and less than or equal to 2 μm, the pore volume ratio relative to the total pore volume is 45.5%, and for pores with a diameter greater than 2 μm and less than or equal to 10 μm, the pore volume ratio relative to the total pore volume Was 15.2%, and for pores with a diameter greater than 10 μm, the pore volume ratio to the total pore volume was 6.2%.

Synthesis of alumina-based porous support Low soda alumina (Na ₂ O content) having an average particle diameter (D50) of 3.2 μm (average aggregated particle diameter (D50) of 40 μm, surface area of 0.5 to 1.0 m ² / g) (Less than 0.08%) 68 parts by mass of coarse particles, 22 parts by mass of fine alumina particles having an average particle size (D50) of 0.6 μm (surface area of 5 to 10 m ² / g), and an average particle size (D50) of 10 μm to 12 μm The following mullite inorganic binder (10 parts by mass) was mixed to obtain an alumina raw material.

  22 parts by mass of water is added to 100 parts by mass of alumina raw material, and 3.0 parts by mass of an organic forming aid (organic binder) together with 7.0 parts by mass of walnut powder as a pore forming agent. Was added). Cellulose aids and wax aids were used as molding aids. The amount of molding aid and water can be adjusted to allow the mixture to be extruded. The resulting mixture was mixed by a kneader and then extruded to obtain a hollow tube molded body having an outer diameter of 8 mm, an inner diameter of 4 mm and a length of 8 mm. The extruded mixture was dried at 60 ° C. to 100 ° C. for 2 hours and placed in a refractory mortar. The mortar consists of a sintered setter fitted with a sintered frame. And the baking process was performed to the extruded mixture using roller hearth kiln. In the firing step, the mortar was exposed to an elevated temperature of 1400 ° C. or higher for 2 hours and held at this temperature for 0.5 hour.

The obtained carrier had a surface area of 0.93 m ² / g, a water absorption of 31.7%, and an apparent porosity of 57%. The total volume of the micropores was found to be 0.32 mL / g. The peak of the pore volume distribution was found to be about 1.1 μm. The pore volume ratio with respect to the total pore volume of pores having a diameter of 1 μm or less was 35.1%. The pore volume ratio with respect to the total pore volume is 30.8% in the pores having a diameter of more than 1 μm and not more than 2 μm, and the pore volume ratio with respect to the total pore volume in the pores having a diameter of more than 2 μm and not more than 10 μm. Was 26.7%, and for pores with a diameter greater than 10 μm, the pore volume ratio to the total pore volume was 7.4%.

Synthesis of alumina-based porous support Low soda alumina (Na ₂ O content) having an average particle diameter (D50) of 3.2 μm (average aggregated particle diameter (D50) of 40 μm, surface area of 0.5 to 1.0 m ² / g) (Less than 0.08%) 77 parts by mass of coarse particles, 13 parts by mass of fine alumina particles having an average particle diameter (D50) of 0.6 μm (surface area of 5 to 10 m ² / g), and an average particle diameter (D50) of 10 μm or more and 12 μm The following mullite inorganic binder (10 parts by mass) was mixed to obtain an alumina raw material.

  With respect to 100 parts by mass of alumina raw material, 22.5 parts by mass of water is added, and 3.0 parts by mass of an organic molding aid (organic) with 7.0 parts by mass of walnut powder as a pore forming agent. Containing binder). Cellulose aids and wax aids were used as molding aids. The amount of molding aid and water can be adjusted to allow the mixture to be extruded. The resulting mixture was mixed by a kneader and then extruded to obtain a hollow tube molded body having an outer diameter of 8 mm, an inner diameter of 4 mm and a length of 8 mm. The extruded mixture was dried at 60 ° C. to 100 ° C. for 2 hours and placed in a refractory mortar. The mortar consists of a sintered setter fitted with a sintered frame. And the baking process was performed to the extruded mixture using roller hearth kiln. In the firing step, the mortar was exposed to an elevated temperature of 1400 ° C. or higher for 2 hours and held at this temperature for 0.5 hour.

The obtained carrier had a surface area of 0.82 m ² / g, a water absorption of 36.5%, and an apparent porosity of 58%. The total volume of the micropores was found to be 0.35 mL / g. The peak of the pore volume distribution was found to be about 1.3 μm. The pore volume ratio with respect to the total pore volume of pores having a diameter of 1 μm or less was 21.1%. For pores with a diameter greater than 1 μm and less than or equal to 2 μm, the pore volume ratio relative to the total pore volume is 42.7%, and for pores with a diameter greater than 2 μm and less than or equal to 10 μm, the pore volume ratio relative to the total pore volume Was 28.6%, and for pores with a diameter greater than 10 μm, the pore volume ratio to the total pore volume was 7.6%.

Synthesis of alumina porous support Low soda alumina (Na ₂ O content) having an average particle diameter (D50) of 2.0 μm (average aggregated particle diameter (D50) of 70 μm, surface area of 0.5 to 1.0 m ² / g) (Less than 0.08%) 72 parts by mass of coarse particles, 18 parts by mass of fine alumina particles having an average particle diameter of 0.6 μm (surface area of 5 to 10 m ² / g), and mullite having an average particle diameter (D50) of 10 μm to 12 μm 10 parts by mass of an inorganic inorganic binder was mixed to obtain an alumina raw material.

  22 parts by mass of water is added to 100 parts by mass of the alumina raw material, and 3.0 parts by mass of an organic molding aid (organic binder) together with 5.0 parts by mass of walnut powder as a pore forming agent. Was added). Cellulose aids and wax aids were used as molding aids. The amount of molding aid and water can be adjusted to allow the mixture to be extruded. The resulting mixture was mixed by a kneader and then extruded to obtain a hollow tube molded body having an outer diameter of 8 mm, an inner diameter of 4 mm and a length of 8 mm. The extruded mixture was dried at 60 ° C. to 100 ° C. for 2 hours and placed in a refractory mortar. The mortar consists of a sintered setter fitted with a sintered frame. And the baking process was performed to the extruded mixture using roller hearth kiln. In the firing step, the mortar was exposed to an elevated temperature of 1400 ° C. or higher for 2 hours and held at this temperature for 0.5 hour.

The obtained carrier had a surface area of 1.04 m ² / g, a water absorption rate of 33.5%, and an apparent porosity of 56%. The total volume of the micropores was found to be 0.34 mL / g. The peak of the pore volume distribution was found to be about 1.3 μm. The pore volume ratio with respect to the total pore volume of pores having a diameter of 1 μm or less was 43.4%. For pores with a diameter greater than 1 μm and less than or equal to 2 μm, the pore volume ratio relative to the total pore volume is 47.5%, and for pores with a diameter greater than 2 μm and less than or equal to 10 μm, the pore volume ratio relative to the total pore volume Was 4.4%, and for pores with a diameter greater than 10 μm, the pore volume ratio to the total pore volume was 4.7%.

Synthesis of alumina porous support Low soda alumina (Na ₂ O content) having an average particle diameter (D50) of 2.0 μm (average aggregated particle diameter (D50) of 70 μm, surface area of 0.5 to 1.0 m ² / g) (Less than 0.08%) 72 parts by mass of coarse particles, 18 parts by mass of fine alumina particles having an average particle size (D50) of 0.5 μm (surface area of 5 to 10 m ² / g), and an average particle size (D50) of 10 μm to 12 μm The following mullite inorganic binder (10 parts by mass) was mixed to obtain an alumina raw material.

  22 parts by mass of water is added to 100 parts by mass of the alumina raw material, and 3.0 parts by mass of an organic molding aid (organic binder) together with 5.0 parts by mass of walnut powder as a pore forming agent. Was added). Cellulose aids and wax aids were used as molding aids. The amount of molding aid and water can be adjusted to allow the mixture to be extruded. The resulting mixture was mixed by a kneader and then extruded to obtain a hollow tube molded body having an outer diameter of 8 mm, an inner diameter of 4 mm and a length of 8 mm. The extruded mixture was dried at 60 ° C. to 100 ° C. for 2 hours and placed in a refractory mortar. The mortar consists of a sintered setter fitted with a sintered frame. And the baking process was performed to the extruded mixture using roller hearth kiln. In the firing step, the mortar was exposed to an elevated temperature of 1400 ° C. or higher for 2 hours and held at this temperature for 0.5 hour.

The obtained carrier had a surface area of 1.01 m ² / g, a water absorption of 32.6%, and an apparent porosity of 55%. The total volume of the micropores was found to be 0.33 mL / g. The peak of the pore volume distribution was found to be about 1.3 μm. The pore volume ratio with respect to the total pore volume of pores having a diameter of 1 μm or less was 41.8%. In the pores having a diameter larger than 1 μm and not larger than 2 μm, the pore volume ratio relative to the total pore volume is 48%, and in the pores having a diameter larger than 2 μm and not larger than 10 μm, the pore volume ratio relative to the total pore volume is 4%. In the pores having a diameter of more than 10 μm, the pore volume ratio with respect to the total pore volume was 5.7%.

Synthesis of alumina porous support Low soda alumina (Na ₂ O content) having an average particle diameter (D50) of 2.0 μm (average aggregated particle diameter (D50) of 70 μm, surface area of 0.5 to 1.0 m ² / g) (Less than 0.08%) 72 parts by mass of coarse particles, 18 parts by mass of fine alumina particles having an average particle size (D50) of 0.4 μm (surface area of 5 to 10 m ² / g), and an average particle size (D50) of 10 μm to 12 μm The following mullite inorganic binder (10 parts by mass) was mixed to obtain an alumina raw material.

  22 parts by mass of water is added to 100 parts by mass of the alumina raw material, and 3.0 parts by mass of an organic molding aid (organic binder) together with 5.0 parts by mass of walnut powder as a pore forming agent. Was added). Cellulose aids and wax aids were used as molding aids. The amount of molding aid and water can be adjusted to allow the mixture to be extruded. The resulting mixture was mixed by a kneader and then extruded to obtain a hollow tube molded body having an outer diameter of 8 mm, an inner diameter of 4 mm and a length of 8 mm. The extruded mixture was dried at 60 ° C. to 100 ° C. for 2 hours and placed in a refractory mortar. The mortar consists of a sintered setter fitted with a sintered frame. And the baking process was performed to the extruded mixture using roller hearth kiln. In the firing step, the mortar was exposed to an elevated temperature of 1400 ° C. or higher for 2 hours and held at this temperature for 0.5 hour.

The obtained carrier had a surface area of 0.99 m ² / g, a water absorption of 31.8%, and an apparent porosity of 55%. The total volume of the micropores was found to be 0.32 mL / g. The peak of the pore volume distribution was found to be about 1.3 μm. The pore volume ratio with respect to the total pore volume of pores having a diameter of 1 μm or less was 41.7%. For pores with a diameter greater than 1 μm and less than or equal to 2 μm, the pore volume ratio relative to the total pore volume is 49.5%, and for pores with a diameter greater than 2 μm and less than or equal to 10 μm, the pore volume ratio relative to the total pore volume Was 4.2%, and for pores with a diameter greater than 10 μm, the pore volume ratio to the total pore volume was 4.6%.

Synthesis of alumina-based porous support Low soda alumina (Na ₂ O content) having an average particle diameter (D50) of 2.2 μm (average aggregated particle diameter (D50) of 90 μm, surface area of 0.5 to 1.0 m ² / g) (Less than 0.08%) 72 parts by mass of coarse particles, 18 parts by mass of fine alumina particles having an average particle diameter (D50) of 0.4 μm (surface area of 5 to 10 m ² / g), and mullite having an average particle diameter of 10 μm to 12 μm 10 parts by mass of an inorganic inorganic binder was mixed to obtain an alumina raw material.

  22 parts by mass of water is added to 100 parts by mass of the alumina raw material, and 3.0 parts by mass of an organic molding aid (organic binder) together with 5.0 parts by mass of walnut powder as a pore forming agent. Was added). Cellulose aids and wax aids were used as molding aids. The amount of molding aid and water can be adjusted to allow the mixture to be extruded. The resulting mixture was mixed by a kneader and then extruded to obtain a hollow tube molded body having an outer diameter of 8 mm, an inner diameter of 4 mm and a length of 8 mm. The extruded mixture was dried at 60 ° C. to 100 ° C. for 2 hours and placed in a refractory mortar. The mortar consists of a sintered setter fitted with a sintered frame. And the baking process was performed to the extruded mixture using roller hearth kiln. In the firing step, the mortar was exposed to an elevated temperature of 1400 ° C. or higher for 2 hours and held at this temperature for 0.5 hour.

The obtained carrier had a surface area of 0.98 m ² / g, a water absorption rate of 35.0%, and an apparent porosity of 57%. The total volume of the micropores was found to be 0.35 mL / g. The peak of the pore volume distribution was found to be about 1.3 μm. The pore volume ratio with respect to the total pore volume of pores having a diameter of 1 μm or less was 38.4%. For pores with a diameter greater than 1 μm and less than or equal to 2 μm, the pore volume ratio relative to the total pore volume is 53.7%, and for pores with a diameter greater than 2 μm and less than or equal to 10 μm, the pore volume ratio relative to the total pore volume Was 3.6%, and for pores with a diameter greater than 10 μm, the pore volume ratio to the total pore volume was 4.3%.

Analysis and characteristics of the supports synthesized according to examples 1 to 7 Tables 1 and 2 below summarize some characteristics of the alumina supports prepared according to examples 1 to 7. The main features recorded are surface area, water absorption, apparent porosity, crushing strength, pore volume distribution, total pore volume and peak pore diameter. Table 3 below summarizes the characteristics of each coarse alumina A, B, and C used in Examples 1-7. Table 4 below summarizes the characteristics of each of the micro aluminas a, b, and c used in Examples 1-7.

  As shown by comparing the results of Examples 1 to 3, as the amount of fine particles increases, the surface area and crushing strength tend to increase, while the water absorption generally decreases. Examples 4-7 show a combination of coarse and fine particles, which are identical, substantially identical, or further improved features compared to the supports described in Examples 1-3. And they all use a combination of 40 μm coarse alumina and 3-5 μm fine alumina. For example, Examples 4-6 use 70 μm coarse alumina in each combination with 0.6 μm, 0.5 μm, or 0.4 μm microalumina, while Example 7 uses in combination with 0.4 μm microalumina. 90 μm coarse alumina is used. The different characteristics found in these supports may make some of the supports more suitable or inappropriate than another support. As there may be different end uses and conditions in which the support is used, any exemplary support described above depends on the end-application, the conditions considered, or the desired result. Can be advantageous or disadvantageous over other supports.

表２．実施例１乃至７により調製されたアルミナ担体の様々な特徴

表３．粗大アルミナＡ、Ｂ及びＣの幾つかの物理的特徴

表４．微小アルミナａ、ｂ及びｃの幾つかの物理的特徴

Table 1. Various features of the alumina support prepared according to Examples 1-7

Table 2. Various features of the alumina support prepared according to Examples 1-7

Table 3. Some physical characteristics of coarse alumina A, B and C

Table 4. Some physical characteristics of micro alumina a, b and c

Synthesis of Another Alumina-Based Porous Support 70 parts by mass of low soda alumina secondary particles, 20 parts by mass of fine alumina particles, and 10 parts by mass of a mullite-based inorganic binder were mixed to obtain an alumina raw material. The low soda alumina secondary particles contain 99.0% or more of Al ₂ O _{3 and} have an average aggregate particle diameter (D50) of 40 μm (average particle diameter (D50) of 3.2 μm, surface area of 0.5 to 1). 0.0 m ² / g, Na ₂ O content of 0.1% or less). The fine alumina particles contain 99.0% or more of Al ₂ O _{3 and} have an average particle diameter (D50) of 0.5 μm (surface area 5 to 10 m ² / g, Na ₂ O content 0.1% or less). . The mullite inorganic binder has an average particle diameter (D50) of 10 μm or less and is present in an amount of 10% of the total mass.

  100 parts by mass of alumina raw material, 28 parts by mass of water and 5 parts by mass of walnut powder as a pore-forming agent, 1.0 part by mass of microcrystalline cellulose and 10 parts by mass of wax emulsion as a molding aid And added as an inorganic binder. The resulting mixture was mixed by a kneader and then extruded to obtain a hollow tube molded body having an outer diameter of 8 mm, an inner diameter of 4 mm and a length of 8 mm. The extruded mixture was dried at 60 ° C. to 100 ° C. for 2 hours and placed in a refractory mortar. The mortar consists of a sintered setter fitted with a sintered frame. And the baking process was performed to the extruded mixture using roller hearth kiln. In the firing step, the extruded mixture was exposed to a maximum sintering temperature (eg, up to 1600 ° C. in certain embodiments) for 2 hours and then held at 1400 ° C. for 0.5 hours.

The obtained carrier had a surface area of 0.9 m ² / g, a water absorption rate of 32%, and an apparent porosity of 55%. The total volume of the micropores was found to be 0.35 mL / g. The peak of the pore volume distribution was found to be about 1.5 μm. The amount of pores in the range of 1-2 μm was 47%, while the amount of pores in the range of less than 1 μm was less than 35%.

  While what has been presently considered to be a preferred embodiment of the invention has been illustrated and described, other and further embodiments are possible without departing from the spirit and scope of the invention as described herein. Those skilled in the art will appreciate that this application includes all modifications within the scope of the claims set forth herein.

Claims (28)

A first portion of alumina particles having an average primary particle size (D50) of 2 μm or more and 6 μm or less;
A second portion of alumina particles having an average primary particle size (D50) of 1 μm or less ;
Look including an alumina containing,
The mass ratio of the first part to the second part is 90:10 to 75:25,
A support for an ethylene epoxidation catalyst further comprising an amount of mullite to enhance stability .   The carrier according to claim 1, wherein an average primary particle size (D50) of the first portion of the alumina particles is 2 µm or more and 5 µm or less. The average primary particle size (D50) of the first portion of the alumina particles is 3 μm or more and 5 μm or less,
The carrier according to claim 1, wherein the average primary particle size (D50) of the second portion of the alumina particles is 1 µm or less. The average primary particle size (D50) of the first portion of the alumina particles is 2 μm or more and 4 μm or less,
The carrier according to claim 1, wherein the average primary particle size (D50) of the second portion of the alumina particles is 1 µm or less. The average primary particle size (D50) of the first portion of the alumina particles is 2 μm or more and 3 μm or less,
The carrier according to claim 1, wherein an average primary particle size (D50) of the second portion of the alumina particles is 1.0 µm or less.   The carrier according to claim 1, wherein the alumina component is α-alumina. Wherein the amount of mullite to enhance stability, carrier of claim 1, wherein the 0.5-20% mullite based on the total weight of the carrier. The carrier according to claim 1, wherein the amount of mullite that enhances the stability is 1 to 15 wt% of mullite based on the total mass of the carrier. Wherein the amount of mullite to enhance stability, carrier of claim 1, wherein the 3～12Wt% of mullite based on the total weight of the carrier.   The support of claim 1 further comprising a promoter amount of rhenium.   The carrier of claim 1 further comprising a cocatalytic amount of an alkali or alkaline earth metal.   The support of claim 1 further comprising a cocatalytic amount of cesium.   The carrier according to claim 1, wherein the carrier has a pore size distribution having a peak pore size of 2 μm or less.   The carrier according to claim 1, wherein 45% or less of the pores have a pore diameter of 1 µm or less. (A) Alumina containing a first portion of alumina particles having an average primary particle size (D50) of 2 μm or more and 6 μm or less, and a second portion of alumina particles having an average primary particle size (D50) of 1 μm or less. A carrier comprising;
(B) a catalytic amount of silver deposited on and / or within the support;
(C) a promoter amount of rhenium deposited on and / or within the support;
Only including,
The mass ratio of the first part to the second part is 90:10 to 75:25,
The ethylene epoxidation catalyst wherein the support further comprises an amount of mullite to enhance stability . The catalyst according to claim 15, wherein an average primary particle size (D50) of the first portion of the alumina particles is 2 µm or more and 5 µm or less. The average primary particle diameter of the first portion of alumina particles (D50) is, is a 3μm or 5μm or less, the average primary particle diameter of the second portion of alumina particles (D50) is, according to claim 15 is 1μm or less The catalyst described. The average primary particle size (D50) of the first portion of the alumina particles is 2 μm or more and 4 μm or less,
The catalyst according to claim 15, wherein an average primary particle size (D50) of the second portion of the alumina particles is 1 µm or less. The average primary particle size (D50) of the first portion of the alumina particles is 2 μm or more and 3 μm or less,
The catalyst according to claim 15, wherein an average primary particle size (D50) of the second portion of the alumina particles is 1.0 µm or less. The catalyst according to claim 15 , wherein the support has a pore size distribution having a peak pore size of 2 μm or less. The catalyst according to claim 15 , wherein 45% or less of the pores have a pore diameter of 1 μm or less. A method for gas phase conversion of ethylene to ethylene oxide in the presence of oxygen, comprising:
The method
(A) Alumina containing a first portion of alumina particles having an average primary particle size (D50) of 2 μm or more and 6 μm or less, and a second portion of alumina particles having an average primary particle size (D50) of 1 μm or less. A carrier comprising;
(B) a catalytic amount of silver deposited on and / or within the support;
(C) a promoter amount of rhenium deposited on and / or within the support;
In the presence of a catalyst comprising, viewed including reacting a reaction mixture comprising ethylene and oxygen,
The mass ratio of the first part to the second part is 90:10 to 75:25,
The method wherein the carrier further comprises an amount of mullite that enhances stability . The method according to claim 22 , wherein the average primary particle size (D50) of the first portion of the alumina particles is 2 µm or more and 5 µm or less. The average primary particle size (D50) of the first portion of the alumina particles is 3 μm or more and 5 μm or less,
The method according to claim 22 , wherein the average primary particle size (D50) of the second portion of the alumina particles is 1 µm or less. The average primary particle diameter of the first portion of alumina particles (D50) is, and the 2μm or 4μm or less, the average primary particle diameter of the second portion of alumina particles (D50) is, claim is 1μm or less 22 The method described. The average primary particle size (D50) of the first portion of the alumina particles is 2 μm or more and 3 μm or less, and the average primary particle size (D50) of the second portion of the alumina particles is 1.0 μm or less. Item 23. The method according to Item 22 . The method according to claim 22 , wherein the carrier has a pore size distribution characterized by having a peak pore size of 2 µm or less. The method according to claim 22 , wherein 45% or less of the pores have a pore diameter of 1 µm or less.