Dehydrogenation catalyst for organic hydrides and method for producing the dehydrogenation catalyst for organic hydrides

Abstract

To provide a dehydrogenation catalyst for organic hydrides that can be produced at low cost while having high activity and high durability, and a method for producing a dehydrogenation catalyst for organic hydrides.SOLUTION: A dehydrogenation catalyst for organic hydrides includes a titanium oxide-containing carrier, a first support metal containing platinum supported by the carrier, and a second support substance containing selenium supported by the carrier. A method for producing a dehydrogenation catalyst for organic hydrides includes the steps of: causing a titanium oxide-containing carrier to support the first support metal containing platinum and; and causing the titanium oxide-containing carrier to support the second support substance containing selenium.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a dehydrogenation catalyst for organic hydrides and a method for producing the same.

Background Art

[0002] In response to the global warming problem, in recent years, there has been a strong demand for the creation of clean energy sources that do not emit GHG (greenhouse gas). Among them, hydrogen can be produced from various resources such as sunlight, fossil fuels, and biomass, and furthermore, since it does not emit CO2 during energy conversion, research has been progressing in many aspects from the production method to the utilization method.

[0003] The organic hydride method is one of the methods for easily handling hydrogen, which is a gas at normal temperature and pressure. Organic hydride is one of the names of handling media, and it has the characteristic of being superior in both mass storage density and volume storage density compared to other handling media such as liquid hydrogen and hydrogen storage alloys. Among organic hydrides, the methylcyclohexane-toluene system in particular has established technologies for transportation and storage, and furthermore, since it has a low melting point and a high boiling point compared to other organic hydrides, it is the most versatile in practical applications.

[0004] In the methylcyclohexane-toluene system, catalysts related to the hydrogenation reaction of adding hydrogen to toluene have been studied for a long time and are already commercialized. However, dehydrogenation catalysts for extracting hydrogen from methylcyclohexane still have problems such as durability improvement and reaction temperature reduction, and have not reached the stage of practical application.

[0005] As a dehydrogenation catalyst for organic hydrides that can maintain high activity for a long time, Patent Document 1 discloses a catalyst including a carrier containing anatase-type titanium oxide and a catalytic metal containing platinum and rhenium supported on the carrier, wherein the mass ratio of the rhenium to the platinum is 0.7 or less.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Patent No. 6583735 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, rhenium is a rare metal, and its market price is very high. Therefore, the addition of rhenium is likely to significantly increase catalyst manufacturing costs in mass production, and cost issues must be resolved in order to commercialize the dehydrogenation catalyst for organic hydrides described in Patent Document 1.

[0008] The present invention was made to solve the above problems, and aims to provide a highly active and highly durable dehydrogenation catalyst for organic hydrides and a method for producing a highly active and highly durable dehydrogenation catalyst for organic hydrides at low cost. [Means for solving the problem]

[0009] (1) The method for producing a dehydrogenation catalyst for organic hydrides according to the present invention involves supporting a first supported metal containing platinum on a support containing titanium oxide having a rutile crystal structure before , sulfur Yellow or arsenic Kao The method is characterized by supporting a second supporting material containing platinum, and then supporting the first supporting metal containing platinum thereafter. (2) In the method for producing a dehydrogenation catalyst for organic hydrides described in (1) above, the amount of platinum supported on the first supported metal is preferably 0.1 to 5.0 parts by mass per 100 parts by mass of the total of the carrier and the first supported metal. (3) In the method for producing a dehydrogenation catalyst for organic hydrides described in (1) or (2) above, it is preferable that the molar ratio of the second supported material to platinum in the first supported metal is 0.001 to 1.0. (4) In the method for producing a dehydrogenation catalyst for organic hydrides described in any of (1) to (3) above, the platinum in the first supported metal is preferably in the form of particles with a particle size of 0.1 to 20 nm. (5) In the method for producing a dehydrogenation catalyst for organic hydrides described in any of (1) to (4) above, it is preferable that the first supported metal and the second supported material do not contain rhenium. (6) In a method for producing a dehydrogenation catalyst for organic hydrides according to any of (1) to (5) above, the carrier containing titanium dioxide , sulfur Yellow or arsenic Kao In the step of supporting the second supported material containing Na2MO x , or (NH4)2MO x It is preferable to form a precursor in any of the following forms. Here, M is the second supported material and x is a natural number.

[0010] (7) The dehydrogenation catalyst for organic hydrides according to the present invention comprises a support containing titanium oxide having an anatase crystal structure, a first supported metal containing platinum supported on the support, and a second supported material containing selenium supported on the support, wherein the molar ratio of the second supported material to platinum in the first supported metal is 0.001 to 0.03. (8) The dehydrogenation catalyst for organic hydrides according to the present invention comprises a support containing titanium oxide having an anatase crystal structure, a first supported metal containing platinum supported on the support, and a second supported material containing selenium supported on the support, wherein the molar ratio of the second supported material to platinum in the first supported metal is 0.001 to 0.01. (9) In the dehydrogenation catalyst for organic hydrides described in (7) or (8) above, the amount of platinum supported on the first supported metal is preferably 0.1 to 5.0 parts by mass per 100 parts by mass of the total of the carrier and the first supported metal. (10) In the dehydrogenation catalyst for organic hydrides described in any of (7) to (9) above, the platinum in the first supported metal is preferably in the form of particles with a particle size of 0.1 to 20 nm. (11) In the dehydrogenation catalyst for organic hydrides described in any of (7) to (10) above, it is preferable that the first supported metal and the second supported material do not contain rhenium. (12) The present invention relates to a method for producing a dehydrogenation catalyst for organic hydrides, which is a method for producing a dehydrogenation catalyst for organic hydrides according to any one of the above (7) to (11), and is characterized by comprising the steps of: supporting a first supported metal containing platinum on a carrier containing titanium oxide; and supporting a second supported material containing selenium on the carrier containing titanium oxide. (13) The aforementioned (12) In the method for producing a dehydrogenation catalyst for organic hydrides described above, in the step of supporting the second supported material containing selenium on the support containing titanium dioxide, Na2MO x , or (NH4)2MO x It is preferable to form a precursor in any of the following forms. Here, M is the second supported material and x is a natural number. (14) The aforementioned (12) or (13) In the method for producing a dehydrogenation catalyst for organic hydrides described above, it is preferable to support the first supported metal containing platinum on the support containing titanium dioxide before supporting the second supported material containing selenium.

[0011] (15) A method for producing a dehydrogenation catalyst for organic hydrides, comprising a carrier containing titanium dioxide having a mixed crystalline structure of rutile and anatase, a first supported metal containing platinum supported on the carrier, and a second supported material containing selenium supported on the carrier, wherein the method comprises the steps of supporting the first supported metal containing platinum on the carrier containing titanium dioxide, and supporting the second supported material containing selenium on the carrier containing titanium dioxide, and it is preferable to support the second supported material before supporting the first supported metal. (16) The aforementioned (15) In the method for producing a dehydrogenation catalyst for organic hydrides described above, it is preferable that the molar ratio of the second supported material to platinum in the first supported metal is 0.001 to 1.0. (17) In the method for producing a dehydrogenation catalyst for organic hydride described in the above ( 15 ) or ( 16 ), in the step of supporting the second supported substance containing selenium on the carrier containing titanium oxide, it is preferable to form a precursor in any form of Na2MO n or (NH4)2MO x . Here, M is the second supported substance, and x is a natural number.

Advantages of the Invention

[0013] According to the present invention, it is possible to provide, at a low cost, a dehydrogenation catalyst for organic hydride having high activity and high durability and a method for producing a dehydrogenation catalyst for organic hydride having high activity and high durability.

Brief Description of the Drawings

[0014] [Figure 1] It is a diagram showing the relationship between the methylcyclohexane conversion rate and the reaction time of Catalysts No. 1, 2, 3, and No. 4. [Figure 2] It is a diagram showing the measurement results by X-ray diffraction of Catalysts No. 5 to 7. [Figure 3] It is a diagram showing the relationship between the methylcyclohexane conversion rate and the reaction time of Catalysts No. 5 to 7. [Figure 4] It is a diagram showing the relationship between the methylcyclohexane conversion rate and the reaction time of Catalysts No. 4 and No. 8 to 10. [Figure 5] It is a diagram showing the relationship between the methylcyclohexane conversion rate and the reaction time of Catalysts No. 4' and No. 9', 23. [Figure 6] It is a diagram showing the relationship between the methylcyclohexane conversion rate and the reaction time of Catalysts No. 4' and No. 9', 22. [Figure 7] It is a diagram showing the relationship between the methylcyclohexane conversion rate and the reaction time of Catalysts No. 2 and No. 11. [Figure 8] ​​This figure shows the relationship between the methylcyclohexane conversion rate and reaction time for catalysts No. 2 and Nos. 11', 13, and 14. [Figure 9] This figure shows the relationship between the methylcyclohexane conversion rate and reaction time for catalysts No. 1 and No. 12. [Figure 10] This figure shows the relationship between the methylcyclohexane conversion rate and reaction time for catalysts No. 1', No. 12', and No. 19. [Figure 11] This figure shows the relationship between the methylcyclohexane conversion rate and reaction time for catalysts No. 1' and Nos. 20 and 21. [Figure 12] This figure shows the relationship between the methylcyclohexane conversion rate and reaction time for catalysts No. 2 and Nos. 15 and 16. [Figure 13] This figure shows the relationship between the methylcyclohexane conversion rate and reaction time for catalysts No. 2 and Nos. 17 and 18. [Figure 14] This figure shows the relationship between the methylcyclohexane conversion rate and reaction time for catalysts No. 2, No. 11', and No. 24. [Figure 15] This figure shows the relationship between the methylcyclohexane conversion rate and reaction time for catalysts No. 2 and Nos. 13 and 25. [Modes for carrying out the invention]

[0015] In the dehydrogenation reaction of methylcyclohexane, a type of organic hydride, it is crucial to suppress the coking phenomenon, where toluene, produced after dehydrogenation, further decomposes on the metal to form carbonides, which then cover the metal surface. Strong Metal-Support Interaction (SMSI) is known as one method that can suppress coking on catalysts.

[0016] SMSI refers to a phenomenon in which a catalyst consisting of a specific combination of support and supported metal exhibits a significant decrease in H2 and CO adsorption capacity after high-temperature reduction treatment, even though metal sintering does not occur. In the state where SMSI is occurring, it is thought that the partially reduced support, due to the high-temperature reduction treatment, covers a portion of the metal surface, donating electrons to the metal, resulting in an electron-rich state. This allows the toluene produced in the methylcyclohexane dehydrogenation reaction to be removed from the metal faster than it can be carbonized. As a result, coking can be prevented, and the activity and durability of the catalyst are thought to be improved.

[0017] The present inventors conducted various studies to obtain a dehydrogenation catalyst for organic hydrides that is highly active, highly durable, and inexpensive to manufacture. As a result, they discovered the dehydrogenation catalyst for organic hydrides and a method for producing the same according to the present invention.

[0018] The following describes embodiments of the present invention, including the reasons for limiting the characteristic technical requirements and preferred embodiments. First, a dehydrogenation catalyst for organic hydrides according to an embodiment of the present invention will be described. In the following description, methylcyclohexane-toluene systems will be used as an example of organic hydrides, but the effects of the present invention are not limited to methylcyclohexane-toluene systems.

[0019] An embodiment of the present invention provides a dehydrogenation catalyst for organic hydrides, characterized by comprising a support containing titanium oxide, a first supported metal containing platinum supported on the support, and a second supported material containing one or more of selenium, sulfur, and arsenic supported on the support.

[0020] (carrier) The dehydrogenation catalyst for organic hydrides according to an embodiment of the present invention includes a support containing titanium dioxide. The support is preferably made of titanium dioxide.

[0021] The crystalline structure of titanium dioxide may be anatase type, rutile type, brookite type, or anatase-rutile mixed type, anatase-brookite mixed type, or rutile-brookite mixed type. Preferably, the crystalline structure of titanium dioxide is anatase type, rutile type, or a mixed type of anatase and rutile. When the crystalline structure of titanium dioxide is anatase type, rutile type, or a mixed type of anatase and rutile, the supported metal supported on the titanium dioxide-containing carrier described later is less likely to coke during the methylcyclohexane dehydrogenation reaction. As a result, the activity of the dehydrogenation catalyst for organic hydrides does not decrease easily even when used for a long time. The crystal structure of titanium dioxide may be measured using X-ray diffraction (X-ray diffractometric analysis). Here, the X-ray diffraction method shall conform to JIS K 0131:1996.

[0022] The reason for the improved activity of catalysts containing titanium dioxide and platinum is thought to be electron transfer from titanium dioxide to platinum due to the expression of SMSI. Generally, anatase-type titanium dioxide has a larger band gap than rutile-type titanium dioxide, resulting in higher reducing ability. This property is utilized in photocatalysts, where anatase-type titanium dioxide is frequently used. In the dehydrogenation reaction of methylcyclohexane, anatase-type titanium dioxide is thought to be able to donate more electrons to platinum than rutile-type titanium dioxide. Therefore, it has been thought that catalysts using anatase-type titanium dioxide are more likely to exhibit SMSI than catalysts using rutile-type titanium dioxide, and that catalysts using anatase-type titanium dioxide are less prone to activity degradation than catalysts using rutile-type titanium dioxide. However, after various studies, the inventors found that catalysts using rutile-type titanium dioxide are even less prone to activity degradation than catalysts using anatase-type titanium dioxide.

[0023] The titanium dioxide-containing carrier may be a porous body composed of numerous aggregated primary particles. The particle size (secondary particle size) of the titanium dioxide-containing carrier may be 100 to 1000 μm.

[0024] The carrier may contain trace components such as metal oxides other than titanium dioxide. Preferably, 80% or more by mass of the total mass of the carrier is titanium dioxide. More preferably, 90% or more by mass is titanium dioxide. Even more preferably, 93% or more by mass is titanium dioxide.

[0025] (First supported metal) An embodiment of the present invention provides a dehydrogenation catalyst for organic hydrides, characterized by containing a first supported metal, including platinum, supported on the carrier.

[0026] The amount of platinum supported in the first supported metal on the carrier is preferably 0.1 to 5.0 parts by mass per 100 parts by mass of the total of the carrier and the first supported metal. If the amount of supported material is less than 0.1 parts by mass relative to 100 parts by mass of the total of the carrier and the first supported metal, the activity of the dehydrogenation catalyst for organic hydrides may be insufficient. It is more preferable that the amount of supported material be 0.5 parts by mass or more relative to 100 parts by mass of the total of the carrier and the first supported metal. On the other hand, if the amount of supported material exceeds 5.0 parts by mass relative to 100 parts by mass of the total of the carrier and the first supported metal, there is a risk of decreased activity due to an increase in the particle size of platinum and an increase in manufacturing costs due to an increase in the amount of platinum used. It is more preferable that the amount of supported material be 3 parts by mass or less relative to 100 parts by mass of the total of the carrier and the first supported metal.

[0027] The shape of the platinum in the first supported metal is not particularly limited, but it is preferably in the form of particles. Furthermore, when the shape of the platinum in the first supported metal is in the form of particles, it is preferable that the particle size of the platinum in the first supported metal is 0.1 nm or larger. Moreover, it is preferable that it is 1.0 nm or larger. On the other hand, as long as the activity can be maintained, there is no need to specifically set an upper limit on the particle size of platinum in the first supporting metal. For example, the upper limit on the particle size of the first supporting metal may be 20 nm or less, or 9 nm or less.

[0028] Particle size was calculated using the H2 chemical adsorption method. Here, the H2 chemical adsorption method conforms to the description in JIS Z8830:2013 (Method for measuring the specific surface area of ​​powders (solids) by gas adsorption).

[0029] (Secondary supported substance) The dehydrogenation catalyst for organic hydrides according to an embodiment of the present invention includes a second supported material containing selenium, which is supported on the carrier. This creates new active sites at the interface between the first supported metal containing platinum and the second supported material containing one or more of selenium, sulfur, and arsenic, thereby promoting the dehydrogenation reaction of organic hydrides, and is presumed to improve the activity of the catalyst.

[0030] In the embodiment of the present invention, the dehydrogenation catalyst for organic hydrides preferably has a molar ratio (M / Pt) of the second supported material M to platinum in the first supported metal of 0.001 to 1.0. For example, if the second supported material is one or more of selenium, sulfur, and arsenic, the above-mentioned M can be expressed as the total molar amount of one or more of selenium, sulfur, and arsenic. If the molar ratio (M / Pt) mentioned above is less than 0.001, it is presumed that the amount of active sites formed at the interface between the first supported metal containing platinum and the second supported material containing one or more of selenium, sulfur, and arsenic will be insufficient, and therefore, a sufficient activity-enhancing effect may not be obtained. On the other hand, if the molar ratio (M / Pt) is greater than 1.0, the activity of the dehydrogenation catalyst for organic hydrides may be insufficient.

[0031] The shape of the second support is not particularly limited, but it is preferable that it is thinly spread over part or all of the surface of the first support metal. This allows for the creation of a sufficient number of active sites between the first support metal containing platinum and the second support material containing selenium, which is presumed to improve the activity of the catalyst.

[0032] Furthermore, since the dehydrogenation catalyst for organic hydrides according to the embodiment of the present invention contains one or more of selenium, sulfur, and arsenic, the amount of rhenium added can be reduced. Since selenium, sulfur, and arsenic are less expensive than rhenium, it is possible to manufacture the dehydrogenation catalyst for organic hydrides at a lower cost. In this embodiment, it is preferable that the first supported metal and the second supported material of the dehydrogenation catalyst for organic hydrides do not contain rhenium.

[0033] Furthermore, the dehydrogenation catalyst for organic hydrides according to the embodiment of the present invention can have higher activity than catalysts that do not contain selenium. This is thought to be because supporting selenium creates new active sites between platinum and selenium, thereby further promoting the dehydrogenation reaction from methylcyclohexane. Therefore, by supporting substances such as selenium, more hydrogen can be extracted from methylcyclohexane.

[0034] In the dehydrogenation catalyst for organic hydrides according to other embodiments of the present invention, since sulfur and arsenic have properties similar to selenium, a secondary support containing sulfur or arsenic may be used instead of a secondary support containing selenium. Alternatively, one or more secondary supports containing selenium, a secondary support containing sulfur, and a secondary support containing arsenic may be mixed and supported. These factors are expected to provide the same activity-enhancing effect as described in the previous embodiment. Furthermore, configurations and preferred ranges other than those described above can be the same as those in the previously described embodiments.

[0035] Next, a method for producing a dehydrogenation catalyst for organic hydrides according to an embodiment of the present invention will be described.

[0036] A method for producing a dehydrogenation catalyst for organic hydrides according to an embodiment of the present invention includes the steps of: supporting a first supported metal containing platinum on a carrier containing titanium oxide; and supporting a second supported material containing one or more of selenium, sulfur, and arsenic on the carrier containing titanium oxide.

[0037] (Process of supporting a first supported metal containing platinum) A method for producing a dehydrogenation catalyst for organic hydrides according to an embodiment of the present invention includes the step of supporting a first supported metal containing platinum on a carrier containing titanium oxide. The method for supporting the first supported metal containing platinum on the carrier containing titanium oxide is not particularly limited, but for example, an impregnation method or an alkoxide method may be used.

[0038] (A process of supporting a secondary support material containing one or more of the following: selenium, sulfur, and arsenic.) A method for producing a dehydrogenation catalyst for organic hydrides according to an embodiment of the present invention includes the step of supporting a second supported material containing one or more of selenium, sulfur, and arsenic on a carrier containing titanium dioxide. The method for supporting the second supported material containing one or more of selenium, sulfur, and arsenic on the carrier containing titanium dioxide is not particularly limited, but for example, an impregnation method or an alkoxide method may be used.

[0039] In the impregnation method or the alkoxide method, Na2MO is used as a precursor material for supporting the second support material. x , or (NH4)2MO x A substance that produces a precursor in any of the following forms can be applied. In these chemical formulas, M represents the secondary support. More specifically, if the secondary support is selenium, Na2SeO4, (NH4)2SeO4, etc. can be applied; if it is sulfur, Na2SO4, (NH4)2SO4, etc. can be applied; and if it is arsenic, Na2AsO4, (NH4)2AsO4, etc. can be applied.

[0040] In the method for producing a dehydrogenation catalyst for organic hydrides according to the embodiment of the present invention, it is preferable to support a second supported material containing one or more of selenium, sulfur, and arsenic on a carrier containing titanium dioxide, and then support the first supported metal containing platinum on top of that. This increases the dispersibility of the first supported metal containing platinum and reduces the particle size. As a result, the activity of the dehydrogenation catalyst for organic hydrides is further improved. [Examples]

[0041] Next, the effects of one aspect of the present invention will be described in more detail with reference to examples. However, the conditions in the examples are merely examples of conditions adopted to confirm the feasibility and effects of the present invention, and the present invention is not limited to these examples of conditions. The present invention can adopt various conditions as long as they do not depart from the spirit of the invention and achieve the objectives of the present invention. In this invention, high activity is defined as a state in which the average conversion rate at reaction times of 5 minutes and 30 minutes is equal to or greater than that of a catalyst consisting of the same type of support and metal combination. The same type of support means that the titanium oxide crystal structure is the same, and if there are two or more types of crystal structures for the support, the ratio of the crystal structures is also the same. The same type of metal means that the first supported metal is the same. Furthermore, in this invention, high durability is defined as a state in which the ratio of the average conversion rate at 5 min and 30 min to the conversion rate at 240 min, i.e., (240 min conversion rate) / (5 min and 30 min average conversion rate), is 0.9 or higher.

[0042] (Activation evaluation of catalysts according to the present invention) Titanium dioxide has three crystalline structures: rutile, anatase, and brookite. Of these, only the rutile and anatase forms are used in practical applications, each possessing distinct characteristics. However, it has not yet been established which is more suitable as a catalyst for the dehydrogenation of methylcyclohexane. Therefore, using rutile-type and anatase-type titanium dioxide as supports, we clarified the effect of differences in the crystal structure of titanium dioxide on the activity of platinum-supported titanium dioxide support catalysts (hereinafter referred to as Pt / TiO2-type catalysts), and then evaluated the activity of catalysts on which one or more of selenium, sulfur, and arsenic were supported on the Pt / TiO2-type catalyst.

[0043] (Selection of titanium dioxide support) For the titanium dioxide support, we used commercially available products or those prepared in-house, including anatase-type alone, rutile-type alone, anatase-rutile mixed type, or JRC-TIO-16, the reference catalyst of the Catalysis Society of Japan. A list of commercially available products and the reference catalyst is shown in Table 1.

[0044] (Catalyst preparation) <Catalyst No. 1-4> Catalysts No. 1 to 4 were prepared by the impregnation method described below. A dinitrodiammineplatinic acid solution was used as the platinum source. The titanium oxide support shown in Table 1 was impregnated with the dinitrodiammineplatinic acid aqueous solution and then dried. Subsequently, catalysts No. 1 to 4 were obtained by calcining at 450°C for 2 hours in a hydrogen gas stream.

[0045] <Catalyst No. 5-7> Catalysts No. 5 to 7 were prepared by first preparing a titanium oxide support using the alkoxide method, and then impregnating and supporting it with platinum. The calcination temperature for catalyst No. 5 was 550°C. The calcination temperature for catalysts No. 6 and 7 was 700°C.

[0046] <Catalyst No. 8~12> Catalysts No. 8 to 12 were prepared by supporting platinum and selenium on a titanium oxide support. Catalysts No. 8 to 10 were prepared by supporting platinum on a titanium oxide support using the same procedure as for catalysts No. 1 to 4, and then impregnating the resulting catalyst with an aqueous sodium selenite solution, followed by evaporation, drying, and calcination. Catalysts No. 11 and 12 were prepared by impregnating a titanium oxide support with an aqueous sodium selenite solution to support selenium, and then impregnating the resulting catalyst with a dinitrodiammineplatinum nitric acid solution, followed by evaporation, drying, and calcination. The firing temperature for catalysts No. 8, No. 9, No. 10, No. 11, and No. 12 was set to 400°C.

[0047] Table 2 shows a list of catalysts prepared by the impregnation method and the alkoxide method. The platinum particle size was calculated by H2 chemisorption, and the crystal structure of the titanium oxide support prepared by the alkoxide method was identified by X-ray diffraction. In addition, as shown in Tables 2 and 3 described later, the following catalysts were prepared separately from catalysts No. 1 to 12 mentioned above and subjected to the tests described later.

[0048] <Other catalysts> Catalyst No. 1' is a catalyst prepared under the same conditions as Catalyst 1, Catalyst No. 4' is a catalyst prepared under the same conditions as Catalyst 4, Catalyst No. 9' is a catalyst prepared under the same conditions as Catalyst 9, Catalyst No. 11' is a catalyst prepared under the same conditions as Catalyst 11, and Catalyst No. 12' is a catalyst prepared under the same conditions as Catalyst 12. These catalysts are comparative test catalysts prepared using the same manufacturing method as described above for each comparative test with other catalysts, which will be explained later. Catalyst No. 13 is a catalyst in which the secondary supported material selenium in catalyst No. 11 is replaced with sulfur (S), and catalyst No. 14 is a catalyst in which the secondary supported material selenium in catalyst No. 11 is replaced with arsenic (As).

[0049] Catalysts No. 15 to 18 were manufactured by first supporting platinum on selenium, as opposed to catalyst No. 11. Catalyst No. 15 has a selenium / platinum molar ratio (M / Pt) of 0.005, catalyst No. 16 has a selenium / platinum molar ratio (M / Pt) of 0.01, catalyst No. 17 has a selenium / platinum molar ratio (M / Pt) of 0.02, and catalyst No. 18 has a selenium / platinum molar ratio (M / Pt) of 0.2. Catalyst No. 19 is a sample in which selenium is replaced with sulfur in catalyst No. 12, catalyst No. 20 is a catalyst in which the loading order of selenium is reversed in catalyst No. 12, and catalyst No. 21 is a catalyst in which selenium is replaced with sulfur in catalyst No. 12 and the loading order is also reversed. The molar ratios (M / Pt) for each catalyst are shown in Tables 2 and 3.

[0050] Catalyst No. 22 is a catalyst in which selenium has been replaced with sulfur in catalyst No. 9, and catalyst No. 23 is a catalyst in which the amount of selenium in catalyst No. 10 has been increased to 0.2. Catalyst No. 24 uses selenium as the secondary support material to observe the effect of the precursor, and uses an NH4 salt precursor instead of the Na salt precursor of catalyst No. 11. Catalyst No. 25 uses sulfur as the secondary support material, and uses an NH4 salt precursor instead of the Na salt precursor of catalyst No. 13.

[0051] The firing temperature for catalysts No. 13, No. 14, No. 15, No. 16, No. 17, No. 18, No. 19, No. 20, No. 21, No. 22, No. 23, No. 24, and No. 25 is 450°C.

[0052] [Table 1]

[0053] [Table 2]

[0054] [Table 3]

[0055] (Influence of the crystal structure of the titanium oxide support) The prepared catalysts No. 1 to 25 were pretreated by hydrogen reduction (17%-H2, 35 ml / min, 350°C, 1 h) and then subjected to the methylcyclohexane dehydrogenation reaction using a fixed-bed flow reactor. The experimental procedure is as follows: Methylcyclohexane was vaporized with N2, the carrier gas, in a stirred oil bath to prepare the raw material gas. The raw material gas was then passed through a catalyst layer installed in an electric furnace and allowed to react. The resulting gas was analyzed for its components using TCD (thermal conductivity detector) and FID (flame ionization detector) gas chromatography.

[0056] The catalyst packing amount was set to 300 μg of platinum. The flow rate of the raw material gas was 40 ml / min (of which MCH was 2.0%, W / F = 16.8 g·min / mol), and the reaction temperature was 280°C. In the experiment, the only product detected was toluene; no by-products were identified.

[0057] Figure 1 and Table 4 show a comparison of the activity of catalysts No. 1, 2, 3, and No. 4. Catalyst No. 1 showed a rapid decrease in activity, while catalysts No. 2, 3, and No. 4 showed a more gradual decrease.

[0058] When examining the platinum particle size of catalysts No. 2, 3, and No. 4, catalyst No. 4 had a small particle size of 2.0 nm, but for the other catalysts, there was little correlation between platinum particle size and conversion rate. However, since catalysts No. 2 and No. 3 both use a rutile-type titanium oxide support, it was suggested that the crystal structure of the titanium oxide support may have some influence on the catalyst activity.

[0059] Therefore, in order to investigate the difference in activity due to differences in crystal structure, titanium oxide supports were prepared by the alkoxide method, and the crystal structure was adjusted by changing the calcination temperature. Then, the activity of catalysts No. 5 to No. 7, on which platinum was supported by the impregnation method, was compared. Figure 2 shows the results of the analysis of the crystal structure of the titanium oxide support by X-ray diffraction. It was found that catalyst No. 5, which was fired at a relatively low temperature, is of the anatase type, while catalysts No. 6 and 7, which were fired at relatively high temperatures, are of the rutile type. The results of the activity comparison are shown in Figure 3 and Table 5. Catalyst No. 5 showed relatively high initial activity, but its conversion rate gradually decreased over time. Catalyst No. 6 had the largest platinum particle size and the lowest activity, while No. 7 showed high initial activity and a gradual decrease in activity. Therefore, the above results demonstrate that catalysts with platinum supported on rutile-type titanium oxide supports exhibit better activity and durability in the methylcyclohexane dehydrogenation reaction than catalysts with platinum supported on anatase-type titanium oxide supports.

[0060] [Table 4]

[0061] [Table 5]

[0062] (Effects of adding selenium) Next, we investigated the effect of adding selenium to Pt / TiO2 catalysts. First, we added a small amount of selenium to Pt / TiO2 catalysts supported by anatase-type titanium dioxide and compared the platinum particle size and conversion rate (catalysts No. 4, 8, 9, and 10). As shown in Table 2, the apparent platinum particle size obtained from the amount of H2 adsorbed tended to increase with the addition of selenium.

[0063] As shown in Figure 4 and Table 6, the reaction results of the catalysts showed that catalyst No. 9, to which approximately 0.01 molar amounts of selenium were added relative to platinum, had a conversion rate approximately 20-30% higher than catalyst No. 4, which did not have added selenium, despite the reduced surface area of ​​the platinum. Therefore, it was shown that adding selenium to a Pt / TiO2 catalyst supported by anatase-type titanium dioxide significantly improved its activity, resulting in high activation. Furthermore, the high activity was maintained even after the reaction time had elapsed, indicating that the catalyst also possessed high durability.

[0064] [Table 6]

[0065] As shown in Figure 5 and Tables 2, 3, and 7, catalyst No. 23, in which Pt was supported on an anatase-type (ST-01) TiO2 support and then Se was supported so that Se / Pt = 0.2, showed decreased activity compared to catalyst No. 4'. Catalyst No. 9', shown in Figure 5, showed a good conversion rate. Together with the result that catalyst No. 9, shown in Figure 4, also showed a good conversion rate, it was shown that Se / Pt = 0.01 is the optimal amount of Se to support.

[0066] [Table 7]

[0067] As shown in Figure 6 and Tables 2, 3, and 7, catalyst No. 22, in which Pt was supported on an anatase-type (ST-01) TiO2 support, and then sulfur (S) was supported in such a way that the optimal loading amount of Se was M / Pt = 0.01, actually showed decreased activity and a reduced conversion rate.

[0068] Next, selenium was added to a Pt / TiO2-based catalyst using rutile-type titanium dioxide as a support (catalyst No. 11), and compared with catalyst No. 2, which did not contain selenium. As shown in Figure 7 and Tables 2 and 8, catalyst No. 11, in which selenium was first impregnated and supported on titanium oxide, and then platinum was supported, showed significantly higher activity than catalyst No. 2, which did not have selenium added, and the conversion rate reached a value close to the equilibrium value. Therefore, it was revealed that the activity of the Pt / TiO2-based catalyst, which uses rutile-type titanium oxide as a support and has selenium pre-supported, was greatly improved. Furthermore, the high activity was maintained even after the reaction time had elapsed, indicating that it also possessed high durability.

[0069] The platinum particle size was 6.1 nm when supported on a titanium oxide support (catalyst No. 2), but it decreased to 3.5 nm when supported on Se / TiO2, suggesting that the selenium on the support may have improved the dispersibility of the platinum. Furthermore, the increased activity due to the addition of selenium suggests that the interface between platinum and selenium may have become a new active site.

[0070] [Table 8]

[0071] The activity of catalysts using sulfur and arsenic as secondary supports was evaluated. As shown in Table 2, the activity of catalyst No. 11, which was a Pt / TiO2-based catalyst with rutile-type titanium oxide as a support and selenium added, was evaluated using catalysts No. 13 and 14, in which selenium was replaced with sulfur. The results were also compared with catalyst No. 2 and with catalyst No. 11'. As shown in Figure 8 and Table 9, the catalyst remained highly active even when selenium was substituted with sulfur or arsenic. Furthermore, compared to catalyst No. 2, catalysts No. 11', 13, and 14 showed high durability.

[0072] [Table 9]

[0073] As shown in Table 2, catalyst No. 12, which was a Pt / TiO2-based catalyst with selenium added to a titanium dioxide mixed form of anatase and rutile supported, was compared with catalyst No. 1, which did not contain selenium. As shown in Figure 9 and Table 10, it was revealed that even when titanium dioxide mixed with anatase and rutile is used as a support, the activity of the catalyst can be improved by adding selenium.

[0074] [Table 10]

[0075] Based on the above findings, in the methylcyclohexane dehydrogenation reaction, catalysts using anatase-type titanium dioxide, rutile-type titanium dioxide, or a mixed form of anatase and rutile titanium dioxide as a support, to which selenium was added, exhibited high activity and durability. Furthermore, it was revealed that when rutile-type titanium dioxide was used as the support, prior loading of selenium increased the catalyst activity to near the equilibrium value. Furthermore, it was revealed that catalysts exhibiting similar high activity and durability can be obtained by using sulfur or arsenic instead of selenium as the secondary support material.

[0076] The activity of a Pt / TiO2-based catalyst, supported with a rutile and anatase-mixed P25, was evaluated by replacing selenium with sulfur. The reaction temperature was set at 280°C, W / F = 16.8 g·min / mol, gas flow rate at 49 mL / min (MCH: 2.0%), and catalyst packing amount at 300 μg (asPt). These conditions are the same as those used for the activity evaluation described below. As shown in Table 3, catalyst No. 19 was prepared by replacing the selenium in catalyst No. 12' with sulfur, and the results of comparing it with catalyst No. 1' are shown in Figure 10 and Table 11.

[0077] [Table 11]

[0078] When Se was supported on TiO2 of a rutile and anatase-mixed type P25 catalyst, followed by Pt, both the activity and stability were significantly improved compared to catalyst No. 1', which was supported only with Pt. Catalyst No. 19, which had sulfur (S) supported instead of se on the same TiO2, showed lower initial activity compared to catalyst No. 1', which had only platinum (Pt) supported. However, it exhibited improved stability and surpassed the activity of the Pt-only catalyst, which degraded over time.

[0079] Catalyst No. 20, shown in Table 3, was prepared by rearranging the selenium loading order of catalyst No. 12, shown in Table 2. Catalyst No. 21, also shown in Table 3, was prepared by replacing selenium with sulfur while rearranging the sulfur loading order. The results of comparing and evaluating the activity of these catalysts with catalyst No. 1' are shown in Figure 11 and Table 11. Catalyst No. 20, in which Pt was supported on TiO2 of a rutile and anatase mixed type P25, and then Se was supported, showed improved activity and stability, but the effect was not as significant as that of catalyst No. 19 shown in Figure 10, in which Se was supported before the Pt. When sulfur (S) was supported on the same TiO2 instead of se, the effect was not as significant as with se, but both the activity and stability were improved compared to catalyst No. 1', which was supported only with platinum (Pt).

[0080] The effect of the loading order was investigated when selenium was supported on a Pt / TiO2-based catalyst with titanium dioxide as the support. Catalysts No. 15 to 18 shown in Table 3 were produced by adding platinum to the selenium-supported form of catalyst No. 11 shown in Table 2, and each catalyst has a different molar ratio of selenium to platinum. Figure 12 and Table 12 show the evaluation results for catalysts No. 15, 16 and catalyst No. 2, while Figure 13 and Table 13 show the evaluation results for catalysts No. 17, 18 and catalyst No. 2.

[0081] [Table 12]

[0082] [Table 13]

[0083] When Se was added to the rutile-type STR-100N TiO2 catalyst after supporting Pt, the activity actually decreased, as shown in Figure 12. Combined with the results shown in Figure 13, varying the amount of Se resulted in lower activity than the catalyst supported only by Pt. This indicates that for rutile-type TiO2 catalysts, good activity cannot be obtained unless Se is supported before Pt.

[0084] (Influence of precursors) To examine the effect of the precursor, catalyst No. 24, shown in Table 3, was prepared using an NH4 salt precursor instead of the Na salt precursor of catalyst No. 11, shown in Table 2. Additionally, catalyst No. 25, shown in Table 3, was prepared using an NH4 salt precursor instead of the Na salt precursor of catalyst No. 13, shown in Table 2, which used sulfur as the secondary support. Catalyst No. 24 used (NH4)2SeO4 as a precursor, as shown in Table 3, and catalyst No. 25 used (NH4)2SO4 as a precursor. The activity evaluation results for catalysts No. 24 and 25 are shown in Figures 14 and 15, and Table 14. Figure 14 shows the activity evaluation results for catalysts No. 2 and No. 11' together, and Figure 15 shows the activity evaluation results for catalysts No. 2 and No. 13 together.

[0085] [Table 14]

[0086] As shown in Figure 14, a comparison of catalysts No. 11' and 24 revealed that when supporting Se or S on the TiO2-based support of rutile-type STR-100N before supporting Pt, the addition of Se was effective and good activity was obtained whether the Se precursor was in the form of an NH4 salt "(NH4)2SeO4" or a Na salt "Na2SeO4". In contrast, when supporting sulfur (S), a comparison of catalysts No. 13 and 25 shown in Figure 15 revealed that while a precursor in the form of a Na salt "Na2SO4" is effective, using an NH4 salt "(NH4)2SO4" precursor (catalyst No. 25) is even better in terms of improving activity. [Industrial applicability]

[0087] Based on the above, the present invention provides a dehydrogenation catalyst for organic hydrides that is highly active and durable, and can be manufactured at low cost, as well as a method for producing the dehydrogenation catalyst for organic hydrides.

Claims

1. A method for producing a dehydrogenation catalyst for organic hydrides, characterized by supporting a second supporting material containing either sulfur or arsenic on a support containing titanium oxide having a rutile-type crystalline structure, before supporting a first supporting metal containing platinum, and then supporting the first supporting metal containing platinum.

2. The method for producing a dehydrogenation catalyst for organic hydrides according to claim 1, characterized in that the amount of platinum supported in the first supported metal is 0.1 to 5.0 parts by mass per 100 parts by mass of the total of the carrier and the first supported metal.

3. A method for producing a dehydrogenation catalyst for organic hydrides according to claim 1 or 2, characterized in that the molar ratio of the second supported material to platinum in the first supported metal is 0.001 to 1.

0.

4. A method for producing a dehydrogenation catalyst for organic hydrides according to any one of claims 1 to 3, characterized in that the platinum in the first supported metal is in the form of particles, and the particle size is 0.1 to 20 nm.

5. A method for producing a dehydrogenation catalyst for organic hydrides according to any one of claims 1 to 4, characterized in that the first supported metal and the second supported material do not contain rhenium.

6. In the step of supporting the second supported substance containing either sulfur or arsenic on the carrier containing titanium dioxide, Na ２ MO ｘ , or (NH ４ ) ２ MO ｘ A method for producing a dehydrogenation catalyst for organic hydrides according to any one of claims 1 to 5, characterized by forming a precursor in any of the following forms. Here, M is a second supported material and x is a natural number.

7. A support containing titanium dioxide with an anatase crystal structure, A first supported metal containing platinum supported on the carrier, A dehydrogenation catalyst for organic hydrides comprising a second supported material containing selenium supported on the carrier, wherein the molar ratio of the second supported material to platinum in the first supported metal is 0.001 to 0.

03.

8. A support containing titanium dioxide with an anatase crystal structure, A first supported metal containing platinum supported on the carrier, A dehydrogenation catalyst for organic hydrides comprising a second supported material containing selenium supported on the carrier, wherein the molar ratio of the second supported material to platinum in the first supported metal is 0.001 to 0.

01.

9. The amount of platinum supported in the first supported metal is 0.1 to 5.0 parts by mass per 100 parts by mass of the total of the carrier and the first supported metal, characterized in that the dehydrogenation catalyst for organic hydrides is as described in claim 7 or 8.

10. The dehydrogenation catalyst for organic hydrides according to any one of claims 7 to 9, characterized in that the platinum in the first supported metal is in the form of particles, and the particle size is 0.1 to 20 nm.

11. The dehydrogenation catalyst for organic hydrides according to any one of claims 7 to 10, characterized in that the first supported metal and the second supported material do not contain rhenium.

12. A method for producing a dehydrogenation catalyst for organic hydrides according to any one of claims 7 to 11, A process of supporting a first supported metal containing platinum on a support containing titanium oxide, A method for producing a dehydrogenation catalyst for organic hydrides, characterized by comprising the step of supporting a second supported material containing selenium on a carrier containing titanium dioxide.

13. In the step of supporting the second supported substance containing selenium on the carrier containing titanium oxide, Na ２ MO ｘ , or (NH ４ ) ２ MO ｘ The method for producing a dehydrogenation catalyst for organic hydride according to claim 12, characterized in that a precursor in any form is formed. Here, M is the second supported substance and x is a natural number.

14. A method for producing a dehydrogenation catalyst for organic hydrides according to claim 12 or 13, characterized in that the first supported metal containing platinum is supported on the carrier containing titanium oxide before the second supported material containing selenium is supported on the carrier containing titanium oxide.

15. A support containing titanium dioxide whose crystalline structure is a mixture of rutile and anatase, A first supported metal containing platinum supported on the carrier, A method for producing a dehydrogenation catalyst for organic hydrides, comprising a second supported material containing selenium supported on the aforementioned carrier, A process of supporting a first supported metal containing platinum on a support containing titanium oxide, The process includes supporting a second supporting material containing selenium on the carrier containing titanium dioxide, A method for producing a dehydrogenation catalyst for organic hydrides, characterized in that the second supported material is supported before the first supported metal is supported.

16. The method for producing a dehydrogenation catalyst for organic hydrides according to claim 15, characterized in that the molar ratio of the second supported material to platinum in the first supported metal is 0.001 to 1.

0.

17. In the step of supporting the second supported material containing selenium on the carrier containing titanium dioxide, Na ２ MO ｘ , or (NH ４ ) ２ MO ｘ A method for producing a dehydrogenation catalyst for organic hydrides according to claim 15 or 16, characterized by forming a precursor in any of the following forms. Here, M is a second supported material and x is a natural number.

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