Hydrogen chloride oxidation catalyst and method for producing hydrogen chloride oxidation catalyst

Abstract

The hydrogen chloride oxidation catalyst is a catalyst for oxidizing hydrogen chloride. The hydrogen chloride oxidation catalyst comprises: a support; and copper, an alkali metal, and a rare earth element. The carrier has alumina as a main component. The copper, the alkali metal and the rare earth element are loaded on the carrier. The ratio of a peak at 2 [theta] = 65.2 DEG in an X-ray diffraction pattern measured by an X-ray diffraction device using a CuK [alpha] ray to the peak intensity of the (440) plane of the alumina crystal in the X-ray diffraction pattern is 0.0015-0.500 inclusive.

Description

Technical Field

[0001] The present invention relates to a hydrogen chloride oxidation catalyst and a method for producing the hydrogen chloride oxidation catalyst. Background Art

[0002] It is known that chlorine can be produced by oxidizing hydrogen chloride in the presence of a catalyst. Such a catalyst may be referred to as a hydrogen chloride oxidation catalyst.

[0003] For example, a hydrogen chloride oxidation catalyst obtained by dispersing copper, potassium, and samarium in alumina is known (for example, see Patent Document 1 listed below).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2009 / 041384 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] However, the hydrogen chloride oxidation catalyst described in Patent Document 1 may collapse and break into powder (pulverization) due to long-term use (operation of a chlorine production apparatus), which may cause clogging and make it difficult to continue producing chlorine.

[0009] Furthermore, the hydrogen chloride oxidation catalyst is required to have excellent activity. If the hydrogen chloride oxidation catalyst has excellent activity, the yield of chlorine in the production of chlorine can be increased.

[0010] The present invention provides a hydrogen chloride oxidation catalyst which can suppress powdering after long-term use and has excellent catalytic activity, and a method for producing the hydrogen chloride oxidation catalyst.

[0011] Means for solving problems

[0012] The present invention [1] comprises a hydrogenation of chloride oxidizing catalyst, which is a hydrogenation of chloride oxidizing catalyst for hydrogenating chloride, comprising: a carrier having aluminum oxide as a main component; and copper, an alkali metal and a rare earth element supported on the carrier, wherein the ratio of the peak at 2θ=65.2° in the X-ray diffraction pattern relative to the peak intensity of the (440) plane of the aluminum oxide crystal in the X-ray diffraction pattern measured by an X-ray diffraction device using CuKα line is 0.0015 or more and 0.500 or less.

[0013] The present invention [2] comprises the hydrogen chloride oxidation catalyst described in [1], wherein the ratio is 0.005 or more and 0.350 or less.

[0014] The present invention [3] comprises the hydrogen chloride oxidation catalyst described in [1] or [2], wherein the support is alumina.

[0015] The present invention [4] comprises the hydrogen chloride oxidation catalyst according to any one of [1] to [3], wherein the hydrogen chloride oxidation catalyst is formed of particles and has a specific surface area of ​​34 m 2 / g or above, 50m 2 / g or less.

[0016] The present invention [5] comprises the hydrogen chloride oxidation catalyst according to any one of [1] to [4], wherein the hydrogen chloride oxidation catalyst is formed of particles and has an average pore diameter of 10 nm to 19 nm.

[0017] The present invention [6] comprises the hydrogen chloride oxidation catalyst described in any one of [1] to [5], wherein the hydrogen chloride oxidation catalyst is formed of particles, and the average particle size of the particles is 1.5 mm or more and 6 mm or less.

[0018] The present invention [7] comprises the hydrogen chloride oxidation catalyst described in any one of [1] to [6], wherein the content of the copper in the hydrogen chloride oxidation catalyst is 1.5% by mass or more and 10.0% by mass or less, the content of the alkali metal in the hydrogen chloride oxidation catalyst is 1.5% by mass or more and 8.0% by mass or less, and the content of the rare earth element in the hydrogen chloride oxidation catalyst is 5.0% by mass or more and 15.0% by mass or less.

[0019] The present invention [8] comprises the hydrogen chloride oxidation catalyst described in any one of [1] to [7], which is a fixed bed catalyst.

[0020] The present invention [9] comprises a method for producing a hydrogen chloride oxidation catalyst, which is the method for producing a hydrogen chloride oxidation catalyst according to any one of [1] to [8], comprising: a step (1) of calcining a carrier at 550° C. or higher and 980° C. or lower; and a step (2) of loading copper, an alkali metal, and a rare earth element on the carrier.

[0021] The present invention

[10] comprises the method for producing a hydrogen chloride oxidation catalyst described in [9], wherein in the aforementioned step (1), the aforementioned support is calcined under the conditions of x hours and y°C, and all of the following formulas (1) to (3) are satisfied.

[0022] 0.25≤x≤50 Formula (1)

[0023] y≤-5.7x+945 Formula (2)

[0024] y≥-5.7x+620 Formula (3)

[0025] The present invention

[11] includes the method for producing a hydrogen chloride oxidation catalyst according to [9] or

[10] , wherein the catalyst satisfies the following formula (4) and formula (5).

[0026] y≤-5.7x+920 Formula (4)

[0027] y≥-5.7x+840 Formula (5)

[0028] Effects of the Invention

[0029] The hydrogen chloride oxidation catalyst of the present invention can suppress powdering after long-term use and has excellent catalytic activity. The production method of the present invention can produce a hydrogen chloride oxidation catalyst that can suppress powdering after long-term use and has excellent catalytic activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] [ Figure 1 ] is an image-processed image of the hydrogen chloride oxidation catalyst of Example 3 after a 35-day hydrogen chloride oxidation test.

[0031] [ Figure 2 ] is an image-processed image of the hydrogen chloride oxidation catalyst of Example 10 after a 35-day hydrogen chloride oxidation test.

[0032] [ Figure 3 ] is an image-processed image of the hydrogen chloride oxidation catalyst of Comparative Example 3 after a 35-day hydrogen chloride oxidation test.

[0033] [ Figure 4 ] shows a schematic cross-sectional view of a fixed-bed catalytic reactor produced in the evaluation of the examples. DETAILED DESCRIPTION

[0034] The hydrogen chloride oxidation catalyst and the method for producing the hydrogen chloride oxidation catalyst of the present invention will be described in order.

[0035] In the numerical ranges described in stages in this disclosure, the upper limit or lower limit described in one numerical range may be replaced by the upper limit or lower limit of the numerical range described in another stage. In addition, in the numerical ranges described in this disclosure, the upper limit or lower limit of the numerical range may also be replaced by the value shown in the embodiments.

[0036] In the present disclosure, when the composition contains a plurality of substances belonging to each component, the amount of each component in the composition refers to the total amount of the plurality of substances present in the composition unless otherwise specified.

[0037] In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.

[0038] In the present disclosure, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes as long as the intended purpose of the process can be achieved.

[0039] 1. Hydrogen chloride oxidation catalyst

[0040] The hydrogen chloride oxidation catalyst is a catalyst for oxidizing hydrogen chloride and comprises: a carrier; and copper, an alkali metal, and a rare earth element.

[0041] 1.1 Carrier

[0042] The carrier contains aluminum oxide as a main component. In other words, the carrier contains aluminum oxide as a main component. Aluminum oxide has a crystalline structure. In this embodiment, the aluminum oxide includes α-aluminum oxide and γ-aluminum oxide. In this embodiment, trace amounts of impurities that are inevitably mixed into the carrier are allowed. The aluminum oxide content in the carrier is, for example, 99.0% by mass or more, preferably 99.5% by mass or more. The aluminum oxide content in the carrier can be calculated from the X-ray diffraction pattern described below.

[0043] The support preferably contains only alumina. In other words, the support is preferably formed of alumina. That is, the support is preferably alumina.

[0044] 1.2 Copper, alkali metals and rare earth elements

[0045] Copper, alkali metals and rare earth elements are active components in the hydrogen chloride oxidation catalyst and are supported on a carrier.

[0046] Examples of the alkali metal include lithium, sodium, potassium, rubidium, cesium, and francium, and potassium is preferred.

[0047] Examples of the rare earth elements include 17 elements, namely scandium, yttrium, and lanthanoid elements (15 elements). Preferably, the lanthanoid elements are used, more preferably, praseodymium, neodymium, lanthanum, europium, and samarium are used, and even more preferably, samarium is used.

[0048] The copper content in the hydrogen chloride oxidation catalyst is, for example, 1.0% by mass or more, preferably 1.5% by mass or more, and more preferably 2.0% by mass or more. The copper content in the hydrogen chloride oxidation catalyst is, for example, 12.0% by mass or less, preferably 10.0% by mass or less, more preferably 9.0% by mass or less, and more preferably 6.0% by mass or less.

[0049] The copper content in the hydrogenation of chloride is preferably 1.0 to 10.0% by mass, more preferably 1.5 to 10.0% by mass, further preferably 2.0 to 9.0% by mass, and particularly preferably 2.0 to 6.0% by mass.

[0050] The content of the alkali metal relative to the hydrogen chloride oxidation catalyst is, for example, 1.0 mass % or more, preferably 1.2 mass % or more, more preferably 1.5 mass % or more, and is, for example, 12.0 mass % or less, preferably 10.0 mass % or less, more preferably 8.0 mass % or less, and further preferably 3.5 mass % or less.

[0051] The content of the alkali metal relative to the hydrogen chloride oxidation catalyst is preferably 1.0 to 12.0 mass%, more preferably 1.2 to 10.0 mass%, further preferably 1.5 to 8.0 mass%, and particularly preferably 1.5 to 3.5 mass%.

[0052] The content of the rare earth element in the hydrogen chloride oxidation catalyst is, for example, 1.0 mass % or more, preferably 3.0 mass % or more, more preferably 5.0 mass % or more, and further preferably 10 mass % or more, and is, for example, 20.0 mass % or less, preferably 18.0 mass % or less, and more preferably 15.0 mass % or less.

[0053] The content of the rare earth element in the hydrogenation of chloride is preferably 1.0 to 20.0 mass%, more preferably 3.0 to 18.0 mass%, further preferably 5.0 to 18.0 mass%, particularly preferably 5.0 to 15.0 mass%, and extremely preferably 10.0 to 15.0 mass%.

[0054] The content of alkali metals per 100 parts by mass of copper is, for example, 20 parts by mass or more, preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and is, for example, 200 parts by mass or less, preferably 150 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 90 parts by mass or less. The content of alkali metals per 100 parts by mass of copper is preferably 20 to 200 parts by mass, more preferably 30 to 150 parts by mass, even more preferably 40 to 100 parts by mass, and particularly preferably 40 to 90 parts by mass.

[0055] The content of the rare earth element relative to 100 parts by mass of copper is, for example, 20 parts by mass or more, preferably 30 parts by mass or more, more preferably 100 parts by mass or more, and, for example, 350 parts by mass or less, preferably 300 parts by mass or less. The content of the rare earth element relative to 100 parts by mass of copper is preferably 20 to 350 parts by mass, more preferably 30 to 350 parts by mass, and even more preferably 100 to 300 parts by mass.

[0056] When the contents of copper, alkali metals, and rare earth elements are within the above-mentioned ranges, copper, alkali metals, and rare earth elements are easily complexed, and the catalytic activity of the hydrogen chloride oxidation catalyst tends to be high.

[0057] The total amount of copper, alkali metals and rare earth elements relative to the hydrogen chloride oxidation catalyst is, for example, 5 mass % or more, preferably 10 mass % or more, more preferably 15 mass % or more, and for example, 25 mass % or less.

[0058] 1.3 Ratio of peak intensity of aluminum oxide crystals in X-ray diffraction pattern

[0059] The ratio of the peak intensity at 2θ=65.2° in the X-ray diffraction pattern of the hydrogen chloride oxidation catalyst to the peak intensity at the (440) plane of the aluminum oxide crystals in the X-ray diffraction pattern of the hydrogen chloride oxidation catalyst measured by an X-ray diffraction apparatus is 0.0015 or more and 0.500 or less. The X-ray diffraction pattern is measured by an X-ray diffraction apparatus using CuKα radiation.

[0060] The peak of the (440) plane of aluminum oxide crystals is a peak derived from γ-alumina crystals. For example, in an X-ray diffraction pattern, the peak of the (440) plane of aluminum oxide crystals is identified as a peak at or near 2θ=67.5°.

[0061] In the present disclosure, the peak at 2θ=65.2° includes a peak near 2θ=65.2°. In other words, the ratio of the peak at 2θ=65.2° or near 2θ in the X-ray diffraction pattern of the hydrogen oxidation catalyst to the peak intensity of the (440) plane of the aluminum oxide crystal in the X-ray diffraction pattern of the hydrogen oxidation catalyst measured by an X-ray diffractometer is 0.0015 or more and 0.500 or less.

[0062] The peak at or near 2θ=65.2° in the X-ray diffraction pattern is assumed to be derived from the (214) plane of α-alumina. This is described in ICDD PDF No. 71-1684.

[0063] The peak intensity of the (440) plane and the peak at 2θ = 65.2° were obtained by fitting a curve obtained by X-ray diffraction analysis using an X-ray diffractometer using the least squares method and performing baseline calibration. The intensity was then determined as the height from the maximum peak to the baseline. X-ray diffraction measurement using the above-mentioned X-ray diffractometer will be described in detail in the Examples below.

[0064] When the above ratio is less than 0.0015, the catalytic activity of the hydrogen chloride oxidation catalyst becomes insufficient. The above situation is speculated to be mainly caused by the following reasons. The content of α-alumina in the carrier becomes too little, so the area of ​​the interface of α-alumina and γ-alumina is reduced. There are a large number of lattice defects (such as oxygen defects) at the interface, and copper, alkali metals and rare earth elements are effectively loaded on the above-mentioned interface. If the area of ​​the interface is reduced, copper, alkali metals and rare earth elements cannot be efficiently stabilized (immobilized) at the interface. Therefore, it is impossible to achieve efficient loading of copper, alkali metals and rare earth elements. As a result, the catalytic activity of the hydrogen chloride oxidation catalyst is reduced.

[0065] When the ratio exceeds 0.500, the catalytic activity of the hydrogen chloride oxidation catalyst becomes insufficient. This is presumably caused primarily by the following reasons. It is assumed that the α-alumina content becomes excessive due to the increase in α-alumina crystals. As a result, the interface area between α-alumina and γ-alumina decreases. Consequently, the catalytic activity of the hydrogen chloride oxidation catalyst decreases.

[0066] The ratio is preferably 0.003 or more, more preferably 0.005 or more, further preferably 0.010 or more, and particularly preferably 0.040 or more. The ratio is preferably 0.400 or less, more preferably 0.350 or less, further preferably 0.300, particularly preferably 0.250 or less, and most preferably 0.200 or less.

[0067] The ratio is preferably 0.003 to 0.400, more preferably 0.005 to 0.350, further preferably 0.010 to 0.300, particularly preferably 0.040 to 0.250, and most preferably 0.04 to 0.200. Furthermore, the ratio is preferably 0.005 to 0.200, more preferably 0.008 to 0.180, and still further preferably 0.010 to 0.160.

[0068] When the ratio is not less than the lower limit and not more than the upper limit described above, the catalytic activity of the hydrogen chloride oxidation catalyst can be further improved.

[0069] Furthermore, from the viewpoint of further improving the catalytic activity of the hydrogen chloride oxidation catalyst, when a graph obtained by X-ray diffraction analysis (measured according to the method described in the Examples) is fitted using the least squares method and baseline correction is performed, the peak intensity at 2θ = 40.8° is preferably 1500 [Intensity [counts]] or less, more preferably 1000 [Intensity [counts]] or less, further preferably 500 [Intensity [counts]] or less, and particularly preferably 100 [Intensity [counts]] or less.

[0070] In order to adjust the ratio to fall within the above range, there is no particular limitation. For example, a method of sequentially carrying out the steps (1) and (2) in the method for producing the hydrogen chloride oxidation catalyst described later can be adopted.

[0071] 1.4 Shape of the Hydrogen Chloride Oxidation Catalyst

[0072] The shape of the hydrogen chloride oxidation catalyst is not particularly limited, and any shape can be used, for example, powder, particle, granular, or pelletized. From the viewpoint of suppressing the pulverization of the hydrogen chloride oxidation catalyst and improving the catalytic activity, the shape of the hydrogen chloride oxidation catalyst is preferably particle-shaped. In other words, it is preferred that the hydrogen chloride oxidation catalyst is formed by particles. The hydrogen chloride oxidation catalyst preferably comprises a large number of particles. The shape of the particles is not particularly limited, for example, spherical, cylindrical, and cylindrical (or strip-shaped) shapes can be mentioned, preferably spherical. The above-mentioned shape can be confirmed, for example, by visual observation. Spherical shapes include true spherical shapes and rotational ellipsoidal shapes.

[0073] 1.5 Specific surface area of ​​hydrogen chloride oxidation catalyst

[0074] The specific surface area of ​​the hydrogen chloride oxidation catalyst is, for example, 15 m 2 / g or more, preferably 20m 2 / g or more, more preferably 30m 2 / g or more, more preferably 34m 2 / g or more, particularly preferably 36m 2 / g or more, and most preferably 38m 2 / g or more. The specific surface area of ​​the hydrogen chloride oxidation catalyst is, for example, 80m 2 / g or less, preferably 60m 2 / g or less, more preferably 50m 2 / g or less, more preferably 37.5m 2 / g or less.

[0075] The specific surface area of ​​the hydrogen chloride oxidation catalyst is, for example, 15 m 2 / g to 80m 2 / g, preferably 20m 2 / g to 60m 2 / g, more preferably 30m 2 / g to 60m 2 / g, more preferably 33m 2 / g to 50m 2 / g. The specific surface area of ​​the hydrogen chloride oxidation catalyst is preferably 34m 2 / g to 37.5m 2 / g, and preferably 38m 2 / g to 48m 2 / g.

[0076] When the specific surface area of ​​the hydrogen chloride oxidation catalyst is greater than or equal to the above lower limit, the contact area between the hydrogen chloride oxidation catalyst and hydrogen chloride can be increased, thereby improving the yield of chlorine. When the specific surface area of ​​the hydrogen chloride oxidation catalyst is less than or equal to the above upper limit, pulverization of the hydrogen chloride oxidation catalyst can be suppressed, and the hydrogen chloride oxidation catalyst can be suitably used as a fixed bed catalyst.

[0077] The specific surface area of ​​the hydrogenation of chloride hydration catalyst can be measured using, for example, a BET method specific surface area measuring apparatus (BELSORP-max, manufactured by Microtrac BEL Corp.).

[0078] 1.6 Average pore diameter

[0079] The average pore diameter of the hydrogen chloride oxidation catalyst is, for example, 1 nm or more, preferably 5 nm or more, more preferably 10 nm or more, and further preferably 15 nm or more. The average pore diameter of the hydrogen chloride oxidation catalyst is, for example, 100 nm or less, preferably 50 nm or less, further preferably 30 nm or less, particularly preferably 19 nm or less, and most preferably 15 nm or less. The average pore diameter of the hydrogen chloride oxidation catalyst is, for example, 1 nm to 100 nm, preferably 5 nm to 50 nm, more preferably 10 nm to 30 nm, and further preferably 10 nm to 19 nm. The average pore diameter of the hydrogen chloride oxidation catalyst is preferably 11 nm to 15 nm. The average pore diameter of the hydrogen chloride oxidation catalyst is preferably 16 nm to 18 nm.

[0080] When the average pore diameter is greater than or equal to the aforementioned lower limit, the diffusion and migration of hydrogen chloride and chlorine can be suppressed. When the average pore diameter is less than or equal to the aforementioned upper limit, the diffusion of hydrogen chloride and chlorine can be accelerated, and the frequency of reaching the surface of the hydrogen chloride oxidation catalyst can be suppressed. Furthermore, the hydrogen chloride oxidation catalyst exhibits excellent balance between suppression of pulverization and catalytic activity.

[0081] The average pore diameter of the hydrogen chloride oxidation catalyst was determined as 4V / A determined by the BET method based on a nitrogen adsorption method.

[0082] 1.7 Average particle size

[0083] The average particle size of the hydrogen chloride oxidation catalyst is, for example, 1 mm or more, preferably 1.5 mm or more, more preferably 2 mm or more, further preferably 2.5 mm or more, and particularly preferably 2.8 mm or more. The average particle size of the hydrogen chloride oxidation catalyst is, for example, 10 mm or less, preferably 6 mm or less, more preferably 4 mm or less, and further preferably 3.5 mm or less. The average particle size of the hydrogen chloride oxidation catalyst is, for example, 1 mm to 10 mm, preferably 1.5 mm to 6 mm, more preferably 2 mm to 4 mm, further preferably 2.5 mm to 3.5 mm, and particularly preferably 2.8 mm to 3.5 mm.

[0084] When the average value of the particle size of the hydrogen chloride oxidation catalyst is not less than the above lower limit, pulverization of the hydrogen chloride oxidation catalyst can be suppressed, and the hydrogen chloride oxidation catalyst can be suitably used as a fixed bed catalyst.

[0085] Furthermore, when the average value of the particle size of the hydrogen chloride oxidation catalyst is equal to or less than the upper limit, the contact area between the hydrogen chloride oxidation catalyst and hydrogen chloride can be increased, and the yield of chlorine can be improved.

[0086] The average value of the particle diameter of the hydrogen chloride oxidation catalyst is the average value of the particle diameters of 100 hydrogen chloride oxidation catalysts. Specifically, when the shape of the hydrogen chloride oxidation catalyst is spherical, the diameter of each of the 100 hydrogen chloride oxidation catalysts is measured to obtain their average value. Specifically, the diameter of 100 hydrogen chloride oxidation catalysts is measured with a vernier caliper to obtain their average value. The method for measuring the average value of the particle diameter of the hydrogen chloride oxidation catalyst is described in the Examples described below.

[0087] 2. Method for producing hydrogen chloride oxidation catalyst

[0088] One embodiment of a method for producing a hydrogen chloride oxidation catalyst will be described. The method for producing a hydrogen chloride oxidation catalyst comprises step (1) and step (2). Step (1) and step (2) are performed sequentially.

[0089] 2.1 Process (1)

[0090] In step (1), the support is calcined. It should be noted that the physical properties of the support described below (including material, shape, specific surface area, average pore diameter, and average particle size) are the physical properties of the support as a raw material for the hydrogen chloride oxidation catalyst, and not the physical properties of the hydrogen chloride oxidation catalyst itself. Specifically, the physical properties of the support described below are the physical properties of the support before calcination.

[0091] The carrier has, for example, aluminum oxide as a main component, preferably aluminum oxide. In the present embodiment, for example, the carrier has γ-alumina as a main component, preferably γ-alumina. As the shape of the carrier, for example, powder, particle, granular or pelletized can be mentioned, preferably particle. As the shape of the particle, for example, spherical, cylindrical and cylindrical (or strip) can be mentioned, preferably spherical. The above shape can be confirmed by visual observation, for example. Spherical shapes include true spherical shapes and rotational elliptical shapes.

[0092] 2.1.1 Carrier

[0093] The specific surface area of ​​the carrier is, for example, 90 m 2 / g or more, preferably 100m 2 / g or more, more preferably 110m 2 / g or more. In addition, the specific surface area of ​​the carrier is, for example, 210m 2 / g or less, preferably 200m 2 / g or less, more preferably 190m 2 / g or less. In addition, the specific surface area of ​​the carrier is, for example, 90m 2 / g to 210m 2 / g, preferably 100m 2 / g to 200m 2 / g, more preferably 110m 2 / g to 190m 2 / g. When the specific surface area of ​​the carrier is above the lower limit, the contact area with hydrogen chloride can be increased, thereby improving the yield of chlorine. When the specific surface area of ​​the carrier is below the upper limit, the pulverization of the hydrogen chloride oxidation catalyst can be suppressed, and further, it can be suitably used as a fixed bed catalyst. The method for measuring the specific surface area of ​​the carrier is the same as that for the hydrogen chloride oxidation catalyst. Alternatively, the specific surface area of ​​the carrier may be a catalog value.

[0094] The average pore diameter of the carrier is, for example, 1 nm or more, preferably 2 nm or more, and more preferably 4 nm or more. The average pore diameter of the carrier is, for example, 20 nm or less, preferably 18 nm or less, and more preferably 16 nm or less. The average pore diameter of the carrier is, for example, 1 nm to 20 nm, preferably 2 nm to 18 nm, and more preferably 4 nm to 16 nm. When the average pore diameter of the carrier is above the above lower limit, the diffusion and movement of hydrogen chloride and chlorine can be suppressed. When the average pore diameter of the carrier is below the above upper limit, the diffusion of hydrogen chloride and chlorine can be accelerated, and the frequency of reaching the surface of the hydrogen chloride oxidation catalyst can be suppressed. In addition, the suppression of pulverization of the hydrogen chloride oxidation catalyst and the balance of catalytic activity are excellent.

[0095] The method for measuring the average pore diameter of the support is the same as that for the hydrogen chloride oxidation catalyst. Alternatively, the average pore diameter of the support may be a catalog value.

[0096] The average value of the particle size of the carrier is, for example, 1 mm or more, preferably 1.2 mm or more, more preferably 1.4 mm or more, and further preferably 1.8 mm or more. The average value of the particle size of the carrier is, for example, 10 mm or less, preferably 6 mm or less, more preferably 4 mm or less, and further preferably 3.5 mm or less. The average value of the particle size of the carrier is, for example, 1 mm to 10 mm, preferably 1.2 mm to 6 mm, more preferably 1.4 mm to 4 mm, further preferably 1.6 mm to 3.5 mm, and particularly preferably 1.8 mm to 3.5 mm. When the average value of the particle size of the carrier is above the above lower limit, the pulverization of the hydrogen chloride oxidation catalyst can be suppressed, and further, it can be suitably used as a fixed bed catalyst. When the average value of the particle size of the carrier is below the above upper limit, the contact area between hydrogen chloride and the hydrogen chloride oxidation catalyst can be increased, and the yield of chlorine can be improved.

[0097] The bulk density of the carrier is, for example, 0.2 g / ml or more, preferably 0.4 g / ml or more, and more preferably 0.6 g / ml or more. The bulk density of the carrier is, for example, 5.0 g / ml or less, preferably 3.0 g / ml or less, and more preferably 1.0 g / ml or less. The g / ml of the carrier is, for example, 0.2 g / ml to 5.0 g / ml, preferably 0.4 g / ml to 3.0 g / ml, and more preferably 0.6 g / ml to 1.0 g / ml.

[0098] When the bulk density of the carrier is above the above lower limit, the pulverization of the hydrogen chloride oxidation catalyst can be suppressed, and further, the catalyst can be suitably used as a fixed bed catalyst. When the bulk density of the carrier is below the above upper limit, the contact area between hydrogen chloride and the hydrogen chloride oxidation catalyst can be increased, and the yield of chlorine can be improved. The method for determining the bulk density of the carrier is described in the Examples described below. Alternatively, the bulk density of the carrier can be a catalog value.

[0099] The method for measuring the average particle size of the carrier is the same as the method for measuring the average particle size of the hydrogen chloride oxidation catalyst. Alternatively, the average particle size of the carrier may be a catalog value.

[0100] 2.1.2 Firing

[0101] In step (1), the support is calcined at a temperature of 550°C to 980°C. The calcination temperature is preferably 580°C or higher, more preferably 620°C or higher, further preferably 660°C or higher, particularly preferably 680°C or higher, and most preferably 820°C or higher. The calcination temperature is preferably 945°C or lower, more preferably 920°C or lower, further preferably 880°C or lower, and particularly preferably 830°C or lower. The calcination temperature is preferably 580°C to 930°C, more preferably 620°C to 880°C, further preferably 660°C to 830°C. The calcination temperature is preferably 680°C to 820°C, and further preferably 830°C to 920°C. It should be noted that the calcination temperature may be increased in stages. If the calcination temperature is above the lower limit and below the upper limit, the catalytic activity of the hydrogen chloride oxidation catalyst can be improved, and the yield of chlorine can be improved.

[0102] The calcination time is, for example, more than 0.25 hour, preferably more than 0.5 hour, more preferably more than 0.75 hour. The calcination time is, for example, less than 50 hours, preferably less than 30 hours, more preferably less than 15 hours, more preferably less than 12 hours. The calcination time is, for example, less than 0.25 hour to 50 hours, preferably less than 0.25 hour to 30 hours, more preferably less than 0.25 hour to 15 hours, more preferably less than 0.5 hour to 12 hours, especially preferably less than 0.75 hour to 12 hours. If the calcination temperature is more than the above-mentioned lower limit, below the upper limit, the catalytic activity of the hydrogen chloride oxidation catalyst can be improved, and the yield of chlorine improves.

[0103] 2.1.3 Relationship between firing time and firing temperature

[0104] In step (1), the support is calcined under the conditions of x hours and y° C., and all of the following formulas (1) to (3) are satisfied.

[0105] 0.25≤x≤50 Formula (1)

[0106] y≤-5.7x+945 Formula (2)

[0107] y≥-5.7x+620 Formula (3)

[0108] If all of the formulas (1) to (3) are satisfied, the catalytic activity of the hydrogen chloride oxidation catalyst can be enhanced, and the yield of chlorine can be improved.

[0109] It is preferable to satisfy the following formulas (4) and (5).

[0110] y≤-5.7x+920 Formula (4)

[0111] y≥-5.7x+840 Formula (5)

[0112] If all of the formulas (4) and (5) are satisfied, the catalytic activity of the hydrogen chloride oxidation catalyst can be further enhanced, and the yield of chlorine can be further improved.

[0113] The carrier is calcined, for example, in air or in an inert gas atmosphere. The carrier is calcined at atmospheric pressure or under reduced pressure. From the perspective of production cost, the carrier is preferably calcined in air or at atmospheric pressure.

[0114] By calcining the support, the support formed of γ-alumina becomes a support containing α-alumina and γ-alumina. α-alumina is identified by a peak at or near 2θ=65.2° in the X-ray diffraction pattern of the support.

[0115] In other words, by calcining the support, the ratio of the peak at 2θ=65.2° of the support to the peak intensity of the (440) plane of the support in the X-ray diffraction pattern falls within the above-described desired range.

[0116] 2.2 Process (2)

[0117] Following step (1), step (2) is carried out. In step (2), copper, alkali metals and rare earth elements are loaded on a carrier. Specifically, copper, alkali metals and rare earth elements are loaded on a carrier calcined under the above conditions. As a loading method, for example, an aqueous solution containing an active ingredient of a compound containing the above-mentioned active ingredient is combined with a carrier and mixed, and then dried. The compound contains chlorides and / or oxides of copper, alkali metals and rare earth elements. Before heating, the atmosphere of the mixture can also be decompressed as needed. The drying temperature is, for example, above 25°C, preferably above 50°C, for example below 250°C, preferably below 150°C, and the above-mentioned mixture is heated. The drying time is not limited.

[0118] The mixture can then be cooled. The cooling temperature can be, for example, 50°C or less, 40°C or less, 0°C or more, or 10°C or more. The cooling temperature includes room temperature, which is 20°C to 25°C. The cooling time is not limited. The mixture can be cooled under reduced pressure.

[0119] In this way, a hydrogen chloride oxidation catalyst was produced.

[0120] 3. Use of hydrogen chloride oxidation catalyst

[0121] The hydrogen chloride oxidation catalyst can be used, for example, in either a batch process or a flow-through process. The hydrogen chloride oxidation catalyst is preferably used in a flow-through process. Examples of the flow-through process include a fixed bed, a fluidized bed, and a moving bed. A preferred flow-through process is a fixed bed. In other words, the hydrogen chloride oxidation catalyst is preferably a fixed bed catalyst.

[0122] The hydrogen chloride oxidation catalyst as a fixed bed catalyst is filled in, for example, a fixed bed reactor. The hydrogen chloride oxidation catalyst forms a hydrogen chloride oxidation catalyst layer in the reactor.

[0123] To oxidize hydrogen chloride using a hydrogen chloride oxidation catalyst, for example, hydrogen chloride is brought into contact with oxygen in the above-mentioned reactor. Chlorine is produced by oxidation of hydrogen chloride. Water is also produced as a by-product of the chlorine production.

[0124] Example

[0125] Hereinafter, the present invention will be described in further detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0126] The physical properties of the support before calcination are described below.

[0127] <Carrier>

[0128] γ-alumina (1), spherical particles, specific surface area 122m 2 / g, average pore diameter (4V / A) 10.4 nm, average particle size 3.2 mm, bulk density 0.71 g / ml (the above specific surface area, average pore diameter, average particle size, and bulk density were each calculated by the measurement method described below. The same applies hereinafter.)

[0129] γ-alumina (2), spherical particles, specific surface area 173m 2 / g, average pore diameter (4V / A) 6.9nm, average particle size 1.9mm, bulk density 0.85g / ml

[0130] Silica, spherical particles, trade name: CARiACT Q15, manufactured by Fuji Silysia Chemical Ltd., specific surface area: 556 m 2 / g, average pore diameter (4V / A) 12.3nm, average particle size 3.1mm, bulk density 0.42g / ml

[0131] <Manufacturing of Hydrogen Chloride Oxidation Catalyst>

[0132] Example 1

[0133] First, a support composed of γ-alumina (1) was calcined in an electric furnace (Yamato Scientific Co., Ltd.: FO510) at 600° C. for 10 hours in an air atmosphere. Thus, step (1) was carried out.

[0134] Separately, an aqueous solution containing the active ingredient was prepared by mixing water, samarium (III) oxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 99.9%), copper (II) chloride dihydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., special reagent grade), potassium chloride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., special reagent grade), and hydrochloric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., Wako first grade, 35.0-37.0%) according to the formulation described in Table 1. Tap water was distilled using a distilled water generator (ADVANTECTOYO KAISHA, LTD.: RFD240NA) until its conductivity reached 5 μS / cm or less.

[0135] After mixing the aqueous solution containing the active ingredient with the calcined support, the mixture was decompressed, heated, dried, and cooled under the conditions shown in Table 2 to support copper, potassium, and samarium on the calcined support. Step (2) was thus implemented.

[0136] The composition ratios (mass %) of copper, potassium, and samarium in the hydrogen chloride oxidation catalyst are shown in Tables 3 and 4.

[0137] Examples 2 to 13, Comparative Examples 1 and 2

[0138] The hydrogen chloride oxidation catalyst was produced by sequentially carrying out steps (1) and (2) in the same manner as in Example 1. However, the contents of copper, potassium, and samarium in the aqueous solution containing the active ingredient, the type of support, and / or the calcination temperature and time of the support in step (1) were changed as shown in Tables 1, 3, and 4.

[0139] Comparative Example 3

[0140] A hydrogen chloride oxidation catalyst was produced in the same manner as in Example 1, except that step (1) was not performed and silica was used instead of γ-alumina (1) as the support.

[0141] Comparative Example 4

[0142] A hydrogen chloride oxidation catalyst was produced in the same manner as in Example 1, except that the support was changed to silica instead of γ-alumina (1).

[0143] Comparative Example 5

[0144] The same procedures as in Example 1 were followed to attempt the production of a hydrogen chloride oxidation catalyst. However, during the calcination step (1), the support was calcined at 1100°C for 5 hours, converting γ-alumina (1) to α-alumina. Consequently, copper, potassium, and samarium could not be sufficiently supported on the support. In other words, in Comparative Example 5, a hydrogen chloride oxidation catalyst could not be produced.

[0145] <Evaluation>

[0146] The following items were evaluated for the hydrogen chloride oxidation catalysts of Examples 1 to 13 and Comparative Examples 1 to 5. The results are shown in Tables 3 and 4.

[0147] <Ratio of the peak at 2θ=65.2° to the peak intensity of the (440) plane of aluminum oxide crystal>

[0148] The hydrogen chloride oxidation catalyst was crushed in an agate mortar to prepare a powder. The powder was then evenly placed in the recess of a glass sample plate (depth 0.2 mm, model: D1T25N, manufactured by Rigaku Holdings Corporation). Using another glass plate, the powder was compressed and formed so that its surface became flat. Thus, a glass sample plate was prepared.

[0149] The glass sample plate was mounted in a wide-angle X-ray diffraction apparatus (apparatus: MiniFlex 600 - manufactured by Crigaku Holdings Corporation, measurement software: SmartLab Studio II). Specifically, the glass sample plate was mounted on a standard sample stage within the sample chamber of the wide-angle X-ray diffraction apparatus. The wide-angle X-ray diffraction apparatus and conditions are as follows.

[0150] Next, a wide-angle X-ray diffraction curve was first measured under the following measurement conditions. A diffraction curve was obtained by wide-angle X-ray diffraction curve measurement. Here, the curve obtained by X-ray diffraction analysis was fitted using the least squares method and baseline correction was performed. The maximum value of the peak appearing near 2θ = 40.8° was 3 [Intensity [counts]].

[0151] If a peak appears near 2θ=65.2° in the baseline-corrected graph, the maximum value of the peak is read. If no clear peak is observed near 2θ=65.2°, the intensity at 2θ=65.2° is read.

[0152] From the baseline-corrected graph, the maximum value of the peak appearing near 2θ=67.5° was defined as the peak intensity of γ-alumina, that is, the peak intensity of the (440) plane of the alumina crystal.

[0153] Then, the ratio of the peak intensity at 2θ=65.2° in the X-ray diffraction pattern to the peak intensity of the (440) plane of the aluminum oxide crystal was calculated. The results are shown in Tables 3 and 4.

[0154] <Optical conditions>

[0155] Slit system: variable + fixed slit system

[0156] Incident Solar: Solar slit 2.5°

[0157] HIS: 10mm

[0158] SS: 13.0mm (Open)

[0159] Light receiving cell: Cell slit 2.5°

[0160] Monochromatization: Kβ filter (×1.5)

[0161] DS: 1.25°

[0162] RS:13.0mm(Open)

[0163] <Measurement conditions>

[0164] Scan axis: 2θ / θ

[0165] Scan mode: 1D (scan)

[0166] Energy Mode: Standard

[0167] Start: 20°

[0168] End: 80°

[0169] Step distance: 0.01°

[0170] Speed: 5° / min

[0171] Tube voltage: 40kV

[0172] Tube current 15mA

[0173] <Average particle size of the support and hydrogen chloride oxidation catalyst before calcination>

[0174] 100 particles of the hydrogen chloride oxidation catalyst were randomly selected and their particle sizes (diameters) were measured using a digital vernier caliper (Mitutoyo Corporation: CD-15CX). The average value of these values ​​was calculated as the average particle size of the hydrogen chloride oxidation catalyst. The average particle size of the support before calcination was also calculated in the same manner as for the hydrogen chloride oxidation catalyst.

[0175] <Specific surface area of ​​the support and hydrogen chloride oxidation catalyst before calcination>

[0176] The specific surface area of ​​each of the support and the hydrogen chloride oxidation catalyst before calcination was measured using a BET specific surface area measuring apparatus (BELSORPmax, manufactured by Microtrac BEL Corp.).

[0177] To measure the specific surface area of ​​the hydrogen chloride oxidation catalyst, the catalyst was heated in an electric furnace (Yamato Scientific Co., Ltd.: FO510) at 200°C for 3 hours under air atmosphere before the pretreatment described below. The heated hydrogen chloride oxidation catalyst was then filled into the measuring container of the measuring apparatus. The measuring apparatus and measurement conditions are shown below.

[0178] Measuring device: BERSORP-max (manufactured by Microtrac BEL Corp.)

[0179] Measurement conditions: Pretreatment: 30°C, 1kPa, 4 hours. Measurement temperature: -196°C

[0180] The specific surface area of ​​the support before calcination was measured in the same manner as the specific surface area of ​​the hydrogen chloride oxidation catalyst, except that the pretreatment temperature was changed from 30°C to 180°C.

[0181] <Average pore diameter of the support and hydrogen chloride oxidation catalyst before calcination>

[0182] The average pore diameter (4V / A) of the hydrogen chloride oxidation catalyst was determined using the BET method based on nitrogen adsorption. It should be noted that the catalyst was previously heated at 200°C for 3 hours in an electric furnace (Yamato Scientific Co., Ltd.: FO510) under an air atmosphere and then filled into the measuring container of the measuring apparatus. The measuring apparatus and measurement conditions are shown below.

[0183] Measuring device: BERSORP-max (manufactured by Microtrac BEL Corp.)

[0184] Measurement conditions: Pretreatment: 30°C, 1kPa, 4 hours. Measurement temperature: -196°C

[0185] The average pore diameter of the support before calcination is also measured in the same manner as the average pore diameter of the hydrogen chloride oxidation catalyst.

[0186] <Bulk density of hydrogen chloride oxidation catalyst>

[0187] A 200 ml graduated cylinder was filled with a hydrogen chloride oxidation catalyst to a volume of 40 ml, and the mass M (g) of the filled hydrogen chloride oxidation catalyst was measured. The bulk density of the support was then calculated using the following formula.

[0188] Bulk density (g / ml) = M (g) / 40 (ml)

[0189] The average pore diameter of the support before calcination was also determined in the same manner as for the hydrogen chloride oxidation catalyst.

[0190] Chlorine yield

[0191] The hydrogen chloride oxidation catalysts of Examples 1 to 13 and Comparative Examples 1 to 4 were brought into contact with hydrogen chloride and oxygen while being heated to produce chlorine.

[0192] In detail, Figure 4 As shown, 6 mL (apparent capacity) of hydrogen chloride oxidation catalyst 3 is filled into a straight tube (an example of a reactor) 2 with a diameter of 1.6 cm to form a catalytic region 4. The length of the catalytic region 4 (the length in the direction in which the straight tube 2 extends) is 3 cm. Thus, a fixed bed catalytic reactor 1 having a straight tube 2, a hydrogen chloride oxidation catalyst 3, a thermocouple 6 and a sleeve 7 is manufactured. The thermocouple 6 can measure the temperature of the hydrogen chloride oxidation catalyst 3. The thermocouple 6 can move in the up and down directions relative to the straight tube 2. The sleeve 7 protects the thermocouple 6. The sleeve 7 has a cylindrical shape with a bottom. The outer diameter of the sleeve 7 is 0.4 mm. In addition, in the fixed bed catalytic reactor 1, the catalytic region 4 is arranged in the center of the long side direction of the straight tube 2.

[0193] Furthermore, the fixed-bed catalytic reactor 1 is provided with a heating furnace 5 that houses the catalytic zone 4. The heating furnace 5 is an electric furnace capable of adjusting the temperature. The heating furnace 5 is programmed to raise the temperature inside the heating furnace 5 so that the temperature of the hydrogen chloride oxidation catalyst 3 returns to the same initial temperature as when the hydrogen chloride oxidation catalyst 3 is initially set during use, if the temperature decreases from the initial temperature set at the start of use.

[0194] In the fixed-bed catalytic reactor 1, hydrogen chloride and oxygen were circulated from the upper end toward the lower end at flow rates of 45 ml / min and 22.5 ml / min, respectively. The temperature of the heating furnace 5 was set so that the temperature of the hydrogen chloride oxidation catalyst 3 reached the reaction temperature listed in Table 4. Note that in Comparative Examples 3 and 4, the flow rates of hydrogen chloride and oxygen were set to 90 ml / min and 90 ml / min, respectively.

[0195] The chlorine yield after 50 hours was then determined. Specifically, after 50 hours, the generated gas was absorbed in 300 ml of a 0.3 mol / l potassium iodide solution (prepared by dissolving potassium iodide (Kanto Chemical, for oxidant measurement) in water) for 10 minutes. The amount of generated chlorine was then measured using a 0.1 mol / l sodium thiosulfate solution (Kanto Chemical) in this potassium iodide solution to determine the chlorine yield.

[0196] Catalyst lifespan

[0197] Regarding Examples 3, 10 to 12, Comparative Examples 1, 3, and 4, 35 days after the reaction was started under the above conditions, the hydrogen chloride oxidation catalyst was taken out and visually observed to confirm the degree of pulverization of the hydrogen chloride oxidation catalyst (including the presence or absence of pulverization).

[0198] The catalyst life is evaluated by the degree of pulverization. The criteria are as follows.

[0199] ○: No powdering was observed.

[0200] △: Powdering is slightly observed.

[0201] ×: Powdering was observed.

[0202] Figure 1 This is an image-processed image of the hydrogen chloride oxidation catalyst of Example 3 after a lapse of 35 days.

[0203] Figure 2 This is an image-processed image of the hydrogen chloride oxidation catalyst of Example 10 after a lapse of 35 days.

[0204] Figure 3 The image-processed image of the hydrogen chloride oxidation catalyst of Comparative Example 3 after 35 days has passed is shown.

[0205] [Table 1]

[0206] Table 1

[0207]

[0208] [Table 2]

[0209] Table 2

[0210] reduced pressure Room temperature, 0.023MPa Warming up 90°C, 0.041 MPa, 1 hour dry 90°C, 0.023 MPa, 2 hours cool down Room temperature, 0.023 MPa, 0.5 hours

[0211] [Table 3]

[0212]

[0213] [Table 4]

[0214]

[0215] It should be noted that the above invention is provided as an exemplary embodiment of the present invention, but it is merely an example and is not to be construed as limiting. Modifications of the present invention known to those skilled in the art are also encompassed by the appended claims.

[0216] Industrial applicability

[0217] The hydrogen chloride oxidation catalyst and the method for producing the hydrogen chloride oxidation catalyst of the present invention can be used for production of chlorine.

Claims

1. A hydrogen chloride oxidation catalyst, which is a hydrogen chloride oxidation catalyst for hydrogen chloride, comprising: A carrier having alumina as a main component; and copper, alkali metals and rare earth elements loaded on the carrier, The ratio of the peak at 2θ=65.2° in the X-ray diffraction pattern to the peak intensity of the (440) plane of the aluminum oxide crystal in the X-ray diffraction pattern measured by an X-ray diffraction device using CuKα rays is greater than or equal to 0.0015 and less than or equal to 0.

500.

2. The hydrogen chloride oxidation catalyst according to claim 1, wherein The ratio is 0.005 or more and 0.350 or less.

3. The hydrogen chloride oxidation catalyst according to claim 1, wherein The carrier is alumina.

4. The hydrogen chloride oxidation catalyst according to claim 1, wherein the hydrogen chloride oxidation catalyst is formed of particles. The specific surface area of ​​the hydrogen chloride oxidation catalyst is 34m 2 / g or above, 50m 2 / g or less.

5. The hydrogen chloride oxidation catalyst according to claim 1, wherein the hydrogen chloride oxidation catalyst is formed of particles. The average pore diameter of the hydrogen chloride oxidation catalyst is 10 nm or more and 19 nm or less.

6. The hydrogen chloride oxidation catalyst according to claim 1, wherein the hydrogen chloride oxidation catalyst is formed of particles. The average particle size of the particles is 1.5 mm or more and 6 mm or less.

7. The hydrogen chloride oxidation catalyst according to claim 1, wherein The copper content in the hydrogen chloride oxidation catalyst is 1.5 mass % or more and 10.0 mass % or less, The content of alkali metal in the hydrogen chloride oxidation catalyst is 1.5 mass % or more and 8.0 mass % or less, The content of the rare earth element in the hydrogen chloride oxidation catalyst is 5.0 mass % or more and 15.0 mass % or less. The hydrogen chloride oxidation catalyst according to claim 1 , which is a fixed bed catalyst.

9. A method for producing a hydrogen chloride oxidation catalyst, the method for producing a hydrogen chloride oxidation catalyst according to any one of claims 1 to 8, comprising: a step (1) of calcining the support at a temperature of not less than 550° C. and not more than 980° C.; and A step (2) of loading copper, alkali metals and rare earth elements on the carrier.

10. The method for producing a hydrogen chloride oxidation catalyst according to claim 9, wherein In the step (1), the support is calcined under the conditions of x hours and y°C. And satisfy all the following equations (1) to (3), 0.25≤x≤50 Formula (1) y≤-5.7x+945 Formula (2) y≥-5.7x+620Formula (3).

11. The method for producing a hydrogen chloride oxidation catalyst according to claim 10, which satisfies the following formula (4) and formula (5): y≤-5.7x+920 Formula (4) y≥-5.7x+840Formula (5).

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