Catalyst for oxidative dehydrogenation reaction and method for producing the same

Abstract

An oxidative dehydrogenation catalyst according to one embodiment of the present application comprises: a support; a first coating layer provided on the support and containing a metal oxide; and a second coating layer provided on the first coating layer and containing a zinc ferrite catalyst, wherein the metal oxide contains one or more metals selected from Ce, K, Mg, La, and Y.

Description

[Technical Field]

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2022-0158634, filed with the Korean Intellectual Property Office on November 23, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to a catalyst for oxidative dehydrogenation reactions and a method for producing the same. [Background technology]

[0003] The demand and value of 1,3-butadiene as an intermediate for petrochemical products is gradually increasing worldwide. 1,3-butadiene is produced by naphtha cracking, direct dehydrogenation of butene, oxidative dehydrogenation of butene, etc.

[0004] However, the naphtha cracking process not only consumes a lot of energy due to the high reaction temperature, but also produces excess base fractions other than 1,3-butadiene because it is not a sole process for producing 1,3-butadiene.Furthermore, the direct dehydrogenation reaction of n-butene is not only thermodynamically unfavorable, but is also an endothermic reaction, and requires high temperature and low pressure conditions to produce 1,3-butadiene at a high yield, making it unsuitable as a commercial process for producing 1,3-butadiene.

[0005] Meanwhile, the oxidative dehydrogenation of butene is a reaction in which butene reacts with oxygen in the presence of a metal oxide catalyst to produce 1,3-butadiene and water, and has the advantage of being thermodynamically very favorable because stable water is produced. Furthermore, unlike the direct dehydrogenation of butene, it is an exothermic reaction, so a high yield of 1,3-butadiene can be obtained even at a lower reaction temperature than the direct dehydrogenation, and since no additional heat supply is required, it can be an effective standalone production process that can meet the demand for 1,3-butadiene.

[0006] The metal oxide catalysts are generally synthesized by a precipitation method, but due to technical and spatial limitations, the production volume per run is small, and in order to meet the target volume, the same process must be repeated several times to produce the catalyst. The catalysts produced in this manner may have different reactivities with reactants depending on the number of runs. Such differences in catalyst reactivity are directly related to the yield of the product (butadiene), and research into reducing these differences in catalyst reactivity is ongoing. Summary of the Invention [Problem to be solved by the invention]

[0007] The present application aims to provide a catalyst for oxidative dehydrogenation that can increase the conversion rate of butene, increase the selectivity for butadiene, and produce butadiene in a high yield, and a method for producing the same. [Means for solving the problem]

[0008] One embodiment of the present application is Carrier; a first coating layer provided on the carrier and comprising a metal oxide; and a second coating layer provided on the first coating layer and including a zinc ferrite-based catalyst; The metal oxide contains one or more metals selected from Ce, K, Mg, La and Y, thereby providing an oxidative dehydrogenation catalyst.

[0009] Also, another embodiment of the present application is After coating the support with a first solution containing a metal oxide precursor, a first heat treatment step is performed to form a first coating layer; and and coating the first coating layer with a second solution containing a zinc ferrite catalyst, and then performing a second heat treatment to form a second coating layer; The metal oxide precursor contains one or more metals selected from Ce, K, Mg, La and Y, and the method for producing the catalyst for oxidative dehydrogenation reaction is provided.

[0010] Also, another embodiment of the present application is providing a catalyst for the oxidative dehydrogenation reaction; and using the oxidative dehydrogenation catalyst in the oxidative dehydrogenation of butene to produce butadiene. The present invention provides a method for producing butadiene, comprising: [Effects of the Invention]

[0011] An oxidative dehydrogenation catalyst according to one embodiment of the present application includes a support on which a first coating layer including a metal oxide and a second coating layer including a zinc ferrite-based catalyst are sequentially formed. This not only prevents coke deposition on the catalyst but also increases the activity of the catalyst.

[0012] Therefore, the oxidative dehydrogenation catalyst according to one embodiment of the present application can provide long-term stability and a higher yield of 1,3-butadiene than conventional zinc ferrite catalysts used in the oxidative dehydrogenation of butene. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram schematically illustrating an oxidative dehydrogenation catalyst according to one embodiment of the present application. [Figure 2] FIG. 1 is a diagram schematically illustrating a conventional catalyst for oxidative dehydrogenation reaction. [Figure 3] FIG. 1 is a diagram schematically illustrating a process of coke formation on the surface of an oxidative dehydrogenation catalyst. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present application will now be described in more detail.

[0015] As used herein, "butadiene" means 1,3-butadiene.

[0016] As mentioned above, ferrite catalysts with a spinel structure (AFe2O4) are known to have good activity as catalysts for the process of producing 1,3-butadiene through the oxidative dehydrogenation of butene.

[0017] On the other hand, ferrite-based catalysts are known to exhibit better reactivity toward 2-butene, especially trans-2-butene, than bismuth-molybdenum catalysts (Mo-Bi catalysts). Therefore, even if Mo-Bi catalysts are used in the oxidative dehydrogenation of 2-butene, the effects of the present invention, i.e., butene conversion or butadiene selectivity, cannot be obtained.

[0018] The ZnFe2O4 catalyst used in the oxidative dehydrogenation of butene is generally prepared by the co-precipitation method, which involves precipitation, stirring, aging, washing, drying, and calcination. The most important step is to uniformly precipitate zinc (Zn) and ferrite (Fe).

[0019] In addition, the zinc ferrite catalyst theoretically forms a spinel structure having the chemical formula ZnFe2O4, and additional functions can be added to the catalyst by adding metals other than Zn and Fe.

[0020] Furthermore, in the oxidative dehydrogenation of butene to produce 1,3-butadiene, catalyst deactivation due to coke formation can occur as the catalytic reaction continues. To prevent this catalyst deactivation and increase long-term stability, the present inventors have investigated methods for adding metals to the catalyst that can help improve oxygen storage capacity, thermal stability, and coke reduction, taking into account oxygen diffusion, a key factor in the oxidative dehydrogenation reaction.

[0021] The process of coke formation on the surface of an oxidative dehydrogenation catalyst is shown schematically in Figure 3. As shown in Figure 3, the Zn-Fe catalyst is reduced during the reaction, generating oxygen vacancies where coke is formed. The generated coke then migrates to the support-catalyst interface. Therefore, one embodiment of the present application aims to provide an oxidative dehydrogenation catalyst that can inhibit the deposition of coke on the catalyst, thereby achieving excellent catalytic activity.

[0022] An oxidative dehydrogenation catalyst according to one embodiment of the present application comprises: a support; a first coating layer provided on the support and containing a metal oxide; and a second coating layer provided on the first coating layer and containing a zinc ferrite catalyst, wherein the metal oxide contains one or more metals selected from Ce, K, Mg, La, and Y.

[0023] In one embodiment of the present application, the size and shape of the carrier may vary depending on the size of the reactor to be used in the reaction, and is not particularly limited, but may be spherical or cylindrical with a diameter of 2 mm to 20 mm.

[0024] In one embodiment of the present application, the support may have a pore structure. There are no particular limitations on the support as long as it has a pore structure, but it may have pores of a size that can accommodate the first coating layer containing the metal oxide and the second coating layer containing the zinc ferrite catalyst.

[0025] According to one embodiment of the present application, the pore structure of the support may have a pore size of 10 μm to 300 μm, and a porosity of 10% to 50% of the total volume of the support.

[0026] The pore size on the surface of the support can be measured by a commonly used technique, including, but not limited to, a mercury porosimeter.

[0027] According to one embodiment of the present application, the pore structure of the carrier is such that the carrier has a pore size of 0.005 m 2 / g~0.5m 2 The surface area of ​​the support may be typically a BET surface area determined by N2 adsorption.

[0028] In one embodiment of the present application, the support may include one or more of alumina, silica, alumina-silica, silicon carbide, titania, and zirconia. More specifically, alumina or alumina / silica may be included, which has a pore structure that allows the first and second coating layers to be stably formed on the support, has few areas where side reactions occur, and does not react with the zinc ferrite catalyst, thereby providing chemical stability.

[0029] An oxidative dehydrogenation catalyst according to one embodiment of the present application comprises a first coating layer provided on the support and containing a metal oxide, wherein the metal oxide contains one or more metals selected from Ce, K, Mg, La, and Y.

[0030] When the metal oxide contains K or Mg, it can effectively remove coke that may be deposited on the catalyst. Also, when the metal oxide contains Ce, La, or Y, it can enhance oxygen diffusion due to its large oxygen storage capacity, thereby suppressing the deposition of coke on the catalyst.

[0031] The first coating layer may be provided on a portion of the surface of the support or on the entire surface of the support, and is preferably provided on the entire surface of the support in order to more effectively prevent coke deposition on the oxidative dehydrogenation catalyst and improve catalytic activity.

[0032] If the first coating layer contains alumina (Al2O3) such as aluminum oxide, the acidity of the alumina, which has acid sites, can cause coke deposition on the alumina, making it impossible to achieve the effect of suppressing the phenomenon of coke deposition on the catalyst of the present invention. Therefore, according to one embodiment of the present application, the first coating layer does not contain alumina.

[0033] An oxidative dehydrogenation catalyst according to one embodiment of the present application includes a second coating layer provided on the first coating layer and including a zinc ferrite-based catalyst.

[0034] The second coating layer may be provided on a portion of the surface of the first coating layer or on the entire surface of the first coating layer. In order to more effectively suppress coke deposition on the oxidative dehydrogenation catalyst and improve catalytic activity, it is preferable that the second coating layer be provided on the entire surface of the first coating layer.

[0035] In one embodiment of the present application, the zinc ferrite catalyst may be represented by the following Chemical Formula 1:

[0036] [Chemical formula 1] ZnFe x O y In the above chemical formula 1, x is 1 to 2.8; y is 1 to 6.

[0037] In the above chemical formula 1, x may be 1 to 2.8, or 1.6 to 2.5, and preferably 1.8 to 2.2.

[0038] In one embodiment of the present application, the content of one or more metals selected from Ce, K, Mg, La, and Y may be 0.05 wt% to 5 wt%, 0.2 wt% to 0.8 wt%, or 0.3 wt% to 0.7 wt%, based on the total weight of the zinc ferrite catalyst. As described above, when the content of one or more metals selected from Ce, K, Mg, La, and Y satisfies the above-mentioned content range, the butene conversion rate and butadiene yield are improved compared to conventional zinc ferrite catalysts. Furthermore, when the content of one or more metals selected from Ce, K, Mg, La, and Y is less than 0.05 wt%, it is difficult to expect improvement in catalyst performance, and when it exceeds 5 wt%, the reaction initiation temperature may be high.

[0039] An oxidative dehydrogenation catalyst according to one embodiment of the present application includes a support on which a first coating layer including a metal oxide and a second coating layer including a zinc ferrite catalyst are sequentially formed, thereby preventing coke deposition on the catalyst.

[0040] As described above, the Zn-Fe catalyst is reduced during the reaction, generating oxygen vacancies where coke is formed. The coke then grows and / or migrates to the support-catalyst interface. In particular, coke precursors weakly adsorbed to the metal can migrate from the metal to the support. In this case, the coke precursors can migrate and reside on acidic supports such as alumina, which can deteriorate the activity and long-term stability of the catalyst. In contrast, a catalyst for oxidative dehydrogenation according to one embodiment of the present application includes a first coating layer containing a metal oxide and a second coating layer containing a zinc ferrite catalyst, sequentially disposed on the support, thereby suppressing coke deposition on the catalyst and increasing its activity.

[0041] An oxidative dehydrogenation catalyst according to one embodiment of the present application is schematically shown in FIG. 1 below, and a conventional oxidative dehydrogenation catalyst is schematically shown in FIG. 2 below.

[0042] As shown in Figure 1 below, an oxidative dehydrogenation catalyst according to one embodiment of the present application comprises a support 10, a first coating layer 20 comprising a metal oxide provided on the support 10, and a second coating layer 30 comprising a zinc ferrite catalyst provided on the first coating layer 20, wherein the metal oxide comprises one or more metals selected from Ce, K, Mg, La, and Y. Also, as shown in Figure 2 below, a conventional oxidative dehydrogenation catalyst comprises a support 10 and a catalyst coating layer 40.

[0043] Furthermore, a method for producing an oxidative dehydrogenation catalyst according to one embodiment of the present application includes the steps of: coating a support with a first solution containing a metal oxide precursor, followed by a first heat treatment step to form a first coating layer; and coating the first coating layer with a second solution containing a zinc ferrite catalyst, followed by a second heat treatment step to form a second coating layer, wherein the metal oxide precursor contains one or more metals selected from Ce, K, Mg, La, and Y.

[0044] In the method for producing an oxidative dehydrogenation catalyst according to one embodiment of the present application, the support, the first coating layer, the second coating layer, the zinc ferrite catalyst, etc. are as described above.

[0045] The metal oxide precursor is a precursor of the metal oxide that constitutes the first coating layer. There are no particular limitations on the metal oxide precursor, and ammonium salts, nitrates, carbonates, chlorides, hydroxides, or mixtures thereof containing one or more metals selected from Ce, K, Mg, La, and Y can be used in combination.

[0046] The first solution and the second solution may each independently further comprise a solvent, which may be any solvent known in the art, such as, but not limited to, water.

[0047] The coating method for the first solution and the second solution may be a method known in the art, such as, but not limited to, dip-coating, wash-coating, etc.

[0048] The first and second heat treatment steps may each independently include drying and calcination steps. The drying may be performed at a temperature of 50°C to 150°C for 1 hour to 48 hours, or at a temperature of 60°C to 100°C for 5 hours to 36 hours, but is not limited thereto. The calcination may be performed in an air atmosphere at a temperature of 350°C to 1,100°C for 1 hour to 10 hours, or at a temperature of 500°C to 1,000°C for 1.5 hours to 8 hours, but is not limited thereto.

[0049] The method for producing an oxidative dehydrogenation catalyst according to an embodiment of the present application may further include preparing the zinc ferrite catalyst. The step of preparing the zinc ferrite catalyst may include contacting a metal precursor solution containing a zinc precursor, a ferrite precursor, and water with a basic aqueous solution to obtain a precipitate; and filtering the precipitate, drying it, and calcining it.

[0050] The content of the zinc precursor may be 0.1 wt % to 5 wt %, or 0.1 wt % to 3 wt %, based on the total weight of the metal precursor solution. Furthermore, the content of the ferrite precursor may be 1 wt % to 10 wt %, or 1 wt % to 7 wt %, based on the total weight of the metal precursor solution. When the contents of the zinc precursor and ferrite precursor are within the above ranges, it is easy to synthesize a zinc ferrite catalyst when forming a precipitate by coprecipitation.

[0051] The zinc precursor and the ferrite precursor may each independently be one or more selected from the group consisting of nitrate, ammonium salt, sulfate, and chloride, or hydrates thereof. Specifically, nitrate, chloride, or hydrates thereof are preferred.

[0052] The zinc precursor may be zinc chloride (ZnCl2), which is excellent for forming zinc ferrite-based catalysts. The ferrite precursor may be ferric chloride hydrate (FeCl3·6H2O), which is excellent for forming zinc ferrite-based catalysts.

[0053] The water may be purified water (DI water). The temperature of the purified water (DI water) may be above 0°C and below 40°C, preferably above 0°C and below 30°C, and more preferably above 5°C and below 25°C. When the temperature of the purified water satisfies the above range, the catalyst production amount by the precipitation method can be increased, the content of the active catalyst can be controlled, and ultimately, the selectivity and yield of butadiene in the oxidative dehydrogenation reaction can be improved.

[0054] The pH of the basic aqueous solution may be 7 to 10. Preferably, the pH may be 7.5 to 9. When the pH satisfies the above range, there is an effect of stably producing a zinc ferrite catalyst.

[0055] The basic aqueous solution may be one or more selected from the group consisting of potassium hydroxide, ammonium carbonate, ammonium bicarbonate, aqueous sodium hydroxide, aqueous sodium carbonate, and aqueous ammonia. Preferably, the basic aqueous solution may be aqueous ammonia. In this case, precipitation is facilitated during the production process of the zinc ferrite catalyst, resulting in excellent formation of catalyst particles.

[0056] The concentration of the basic aqueous solution may be 20% by weight to 40% by weight, or 25% by weight to 30% by weight.

[0057] The step of obtaining the precipitate may further include a step of stirring the metal precursor solution after contacting it with the basic aqueous solution. The step of stirring facilitates precipitation of the metal precursor, which is advantageous for the formation of catalyst particles. The stirring step may be performed at room temperature, and any stirring method may be used as long as it is a method of mixing liquids. The stirring time for the stirring step may be 30 minutes to 3 hours, or 1 hour to 2 hours.

[0058] The step of filtering the precipitate is not particularly limited as long as it is a filtering method commonly used in the art. For example, it may be vacuum filtration. Specifically, it may be a method of filtering under reduced pressure using a vacuum pump, which has the effect of washing and separating water from the catalyst.

[0059] The method may further include a step of washing the precipitate after filtering and before calcining, whereby unnecessary ions remaining in the precipitate can be removed.

[0060] The drying step can be performed after filtering and washing the precipitate and before calcining. The method for drying the precipitate is not particularly limited as long as it is a drying method commonly used in the relevant field. For example, a dryer or an oven can be used. The drying step can be performed at a temperature of 80°C to 150°C.

[0061] The step of calcining the precipitate may involve raising the temperature from 80°C at a rate of 1°C / min and maintaining it at 600°C to 800°C for 5 to 10 hours. Specifically, the calcination step may be performed at 600°C to 700°C, more specifically, 600°C to 650°C. Specifically, the calcination step may be performed for 5 to 8 hours, more specifically, 5 to 6 hours.

[0062] The calcination method may be a heat treatment method commonly used in the art.

[0063] Furthermore, one embodiment of the present application provides a method for producing butadiene, including the steps of: preparing the above-mentioned oxidative dehydrogenation catalyst; and using the above-mentioned oxidative dehydrogenation catalyst in the oxidative dehydrogenation of butene to produce butadiene.

[0064] In one embodiment of the present application, the step of producing butadiene comprises reacting a raw material containing a C4 fraction, steam, oxygen (O2), and nitrogen (N2) at a reaction temperature of 400°C to 600°C, a pressure of 0.1 bar to 10 bar, and a GHSV (Gas Hourly Space Velocity) of 200 h. -1 ~400h -1 The reaction may be carried out under the following conditions.

[0065] The C4 fraction may refer to C4 raffinate-1, 2, 3 remaining after separating useful compounds from a C4 mixture produced by naphtha cracking, or may refer to C4s obtainable through ethylene dimerization.

[0066] In one embodiment of the present application, the C4 fraction may be a mixture of one or more selected from the group consisting of n-butane, trans-2-butene, cis-2-butene, and 1-butene.

[0067] In one embodiment of the present application, the steam or nitrogen (N) is a dilution gas introduced in the oxidative dehydrogenation reaction for the purposes of reducing the risk of explosion of the reactants, preventing coking of the catalyst, and removing the heat of reaction.

[0068] In one embodiment of the present application, the oxygen (O2) acts as an oxidant to react with the C4 fraction to cause a dehydrogenation reaction.

[0069] In one embodiment of the present application, the oxidative dehydrogenation reaction can be carried out according to the following Reaction Scheme 1 or Reaction Scheme 2. [Reaction Scheme 1] C4H8+1 / 2O2 → C4H6+H2O [Reaction Scheme 2] C4H 10 +O2 → C4H6+2H2O

[0070] In the oxidative dehydrogenation reaction, butadiene is produced by removing hydrogen from butane or butene. Meanwhile, the oxidative dehydrogenation reaction may produce by-products, such as carbon monoxide (CO) or carbon dioxide (CO), in addition to the main reaction shown in Reaction Scheme 1 or 2. The process may include a step of separating and discharging the by-products to the outside of the system to prevent their continuous accumulation within the process. [Example]

[0071] Hereinafter, the present application will be described in detail with reference to examples in order to specifically explain the present application. However, the examples of the present application can be modified in various different forms, and the scope of the present application should not be construed as being limited to the examples detailed below. The examples of the present application are provided to more completely explain the present application to those skilled in the art.

[0072] <Example> Example 1: Ce 0.5 wt% supported 1) Production of zinc ferrite catalysts A metal precursor solution was prepared by dissolving 12.019 g of zinc chloride (ZnCl2) and 47.662 g of ferric chloride (FeCl3) in 155.59 g of distilled water. The molar ratio of the metal components contained in the metal precursor solution was Zn:Fe = 1:2. Ammonia water solution was added dropwise to the prepared metal precursor solution to adjust the pH to 9, and the solution was stirred for 1 hour to allow for co-precipitation. The coprecipitate was then obtained by filtering the coprecipitate under reduced pressure. This coprecipitate was then dried at 90°C for 16 hours, and then heated in an air atmosphere from 80°C to 650°C at a rate of 1°C / min and maintained for 6 hours to produce zinc-iron oxide (ZnFe2O4) powder with a spinel structure.

[0073] 2) Preparation of Ce precursor solution A Ce precursor solution was prepared by diluting Ce(NO3)3·6H2O in water (200 mL) so that the weight of Ce was 0.5 wt% based on the weight of zinc-iron oxide (ZnFe2O4) powder.

[0074] 3) Preparation of the first coating layer containing a metal oxide A porous aluminum silicate support was immersed in the Ce precursor solution, and water was evaporated under reduced pressure at 90°C. The support supporting the Ce precursor was dried at 120°C for 16 hours. The temperature was then increased from 80°C to 650°C at a rate of 1°C / min in an air atmosphere and maintained at this temperature for 6 hours to produce a support having a first coating layer containing Ce oxide.

[0075] 4) Production of catalysts for oxidative dehydrogenation reactions The prepared zinc-iron oxide powder was crushed to 180 μm or less and diluted with water to prepare a catalyst slurry. The support having the first coating layer containing Ce oxide was immersed in the catalyst slurry, aerated, and dried at 120°C for 1 hour. The dried porous aluminum silicate support was then immersed in the catalyst slurry again, aerated, and dried, and this process was repeated three times. The resulting catalyst was dried at 120°C for 16 hours and then heated in an air atmosphere from 80°C to 650°C at a heating rate of 1°C / min and maintained for 6 hours to prepare a porous oxidative dehydrogenation catalyst.

[0076] Example 2: La 0.5 wt% supported The same procedure as in Example 1 was carried out except that the La precursor solution was used instead of the Ce precursor solution. The La precursor solution was prepared by diluting La(NO) with water so that the weight of La was 0.5 wt % based on the weight of the zinc-iron oxide (ZnFeO) powder.

[0077] Example 3: K 0.5 wt% supported The same procedure as in Example 1 was carried out, except that a K precursor solution was used instead of the Ce precursor solution. The K precursor solution was prepared by diluting KNO with water so that the weight of K was 0.5 wt % based on the weight of the zinc-iron oxide (ZnFeO) powder.

[0078] Example 4: 0.5 wt% Mg supported The same procedure as in Example 1 was carried out except that an Mg precursor solution was used instead of the Ce precursor solution. The Mg precursor solution was prepared by diluting Mg(NO) with water so that the weight of Mg was 0.5 wt % based on the weight of the zinc-iron oxide (ZnFeO) powder.

[0079] Example 5: Y 0.5 wt% supported The same procedure as in Example 1 was carried out, except that a Y precursor solution was used instead of the Ce precursor solution. The Y precursor solution was prepared by diluting Y(NO) with water so that the weight of Y was 0.5 wt % based on the weight of the zinc-iron oxide (ZnFeO) powder.

[0080] <Comparative Example 1> 1) Production of zinc ferrite catalysts Zinc-iron oxide (ZnFe2O4) powder was produced in the same manner as in the production of the zinc ferrite catalyst in Example 1 above.

[0081] 2) Production of catalysts for oxidative dehydrogenation reactions The zinc-iron oxide powder was crushed to 180 μm or less and diluted with water at a 1:1 weight ratio to prepare a catalyst slurry. A porous aluminum silicate support was immersed in the catalyst slurry, aerated, and dried at 120°C for 1 hour. The dried porous aluminum silicate support was then immersed in the catalyst slurry, aerated, and dried three times. The resulting catalyst was dried at 120°C for 16 hours and then heated in an air atmosphere from 80°C to 650°C at a heating rate of 1°C / min and maintained for 6 hours to prepare a porous oxidative dehydrogenation catalyst.

[0082] <Comparative Example 2> Addition of 0.5wt% Ce 1) Production of zinc ferrite catalysts Zinc-iron oxide (ZnFe2O4) powder was produced in the same manner as in the production of the zinc ferrite catalyst in Example 1 above.

[0083] 2) Production of catalysts for oxidative dehydrogenation reactions An oxidative dehydrogenation catalyst was prepared in the same manner as in Comparative Example 1, except that Ce(NO)·6H0 was added to prepare the catalyst slurry so that the weight of Ce was 0.5 wt % based on the weight of the zinc-iron oxide (ZnFeO) powder.

[0084] <Comparative Example 3> Addition of 0.5wt% La 1) Production of zinc ferrite catalysts Zinc-iron oxide (ZnFe2O4) powder was produced in the same manner as in the production of the zinc ferrite catalyst in Example 1 above.

[0085] 2) Production of catalysts for oxidative dehydrogenation reactions An oxidative dehydrogenation catalyst was prepared in the same manner as in Comparative Example 1, except that La(NO) was further added so that the weight of La was 0.5 wt % based on the weight of the zinc-iron oxide (ZnFeO) powder during the preparation of the catalyst slurry.

[0086] <Experimental Example 1> Analysis of catalyst for oxidative dehydrogenation reaction The metal content in the oxidative dehydrogenation catalysts prepared in the above examples and comparative examples can be analyzed using ICP (Inductively Coupled Plasma) analysis. The ICP analysis can be performed using an ICP-OES (Inductively Coupled Plasma-Optical Emission) instrument. More specifically, an ICP-OES (Optima 7300DV) instrument can be used, and the procedure is as follows:

[0087] <Experimental method 1, analysis of main components (Fe, Zn)> 1) Approximately 0.01 g of sample is placed in a platinum crucible and the weight is measured accurately. 2) Add 3 mL of concentrated hydrochloric acid and shake well to mix. 3) The sample is heated to decompose (130°C, 3 hours). 4) Once the sample is dissolved, cool it to room temperature, add 500 μL of Sc internal standard solution, and dilute with ultrapure water to a total volume of 50 mL. 5) Measure using ICP-OES. If the value exceeds the calibration range, further dilute and measure.

[0088] <Experimental Method 2, Microanalysis> 1) Approximately 0.1 g of sample is placed in a platinum crucible and the weight is measured accurately. 2) Add 3 mL of concentrated hydrochloric acid and shake well to mix. 3) The sample is heated to decompose (130°C, 3 hours). 4) Once the sample is dissolved, cool it to room temperature, add 100 μL of Sc internal standard solution, and dilute with ultrapure water to a total volume of 10 mL. 5) Measure using ICP-OES. If the value exceeds the calibration range, further dilute and measure.

[0089] <Experimental Example 2> Production of butadiene 300℃~600℃, GHSV=50h -1 ~200h -1 1,3-Butadiene was produced by oxidative dehydrogenation using the zinc ferrite catalysts prepared in the examples and comparative examples under the conditions of OBR=0.5-1.5, SBR=6-10, and NBR=1. OBR=Oxygen / total 2-butene ratio SBR=Steam / total 2-butene ratio NBR=Nitrogen / total 2-butene ratio

[0090] In addition, in the oxidative dehydrogenation reaction of butene, the butene conversion rate, butadiene selectivity, butadiene yield, etc. were measured and are shown in Table 1 below.

[0091] In this specification, the "yield (%)" is defined as the value obtained by dividing the number of moles of 1,3-butadiene, which is the product of the oxidative dehydrogenation reaction, by the number of moles of butene, which is the raw material. For example, the yield can be expressed by the following formula. Yield (%) = [(moles of 1,3-butadiene produced) / (moles of butene fed)] × 100

[0092] As used herein, the term "conversion (%)" refers to the rate at which reactants are converted to products. For example, the conversion rate of butene can be defined by the following formula: Conversion rate (%) = [(number of moles of reacted butene) / (number of moles of fed butene)] × 100

[0093] In this specification, "selectivity (%)" is defined as the change in butadiene (BD) divided by the change in butene (BE). For example, selectivity can be expressed by the following formula: Selectivity (%) = [(number of moles of 1,3-butadiene or COx produced) / (number of moles of butene reacted)] × 100

[0094] <Experimental Example 3> Analysis of coke production To measure the amount of coke produced by the catalysts of the Examples and Comparative Examples recovered after the reaction, thermogravimetric analysis was carried out using a Waters TGA 550. The analysis conditions were an air atmosphere with a temperature rise rate of 10°C / min from 50°C to 650°C, and a flow rate of 60 cm3 of air. 3 / min, balance N240cm 3 The amount of coke produced and the coke reduction rate were measured and are shown in Table 1 below.

[0095] In this specification, the amount of coke produced (wt%) is defined as a value indicating the weight change amount according to the TGA analysis results. For example, the amount of coke produced can be expressed by the following formula: Coke production (wt%) = [(weight of catalyst before TGA analysis - weight of catalyst after TGA analysis) / (weight of catalyst before TGA analysis)] × 100

[0096] In this specification, the coke reduction rate (%) is defined as a value indicating the change in the amount of coke produced. For example, the coke reduction rate can be expressed by the following formula: Coke reduction rate (%) = [(amount of coke produced in Comparative Example 1 - amount of coke produced in Example or Comparative Example) / (amount of coke produced in Comparative Example 1)] × 100

[0097] [Table 1]

[0098] As can be seen from the above results, the oxidative dehydrogenation catalysts of Examples 1 to 5 of the present application produced less coke and exhibited a superior coke reduction rate compared to the oxidative dehydrogenation catalysts of Comparative Examples 1 to 3. In particular, a comparison of Example 1 and Comparative Example 2 shows that forming an additional metal oxide in the first coating layer of the oxidative dehydrogenation catalyst, as shown in Figure 1 below, not only inhibits coke deposition on the catalyst but also increases the activity of the catalyst.

[0099] An oxidative dehydrogenation catalyst according to one embodiment of the present application includes a support on which a first coating layer including a metal oxide and a second coating layer including a zinc ferrite-based catalyst are sequentially formed. This not only prevents coke deposition on the catalyst but also increases the activity of the catalyst.

[0100] Furthermore, the oxidative dehydrogenation catalyst according to one embodiment of the present application can provide long-term stability and a higher yield of 1,3-butadiene than conventional zinc ferrite catalysts used in the oxidative dehydrogenation of butene. [Explanation of symbols]

[0101] 10: Carrier 20: First coating layer 30: Second coating layer 40: Catalyst coating layer

Claims

1. Carrier; a first coating layer provided on the carrier and comprising a metal oxide; and a second coating layer provided on the first coating layer and including a zinc ferrite-based catalyst; The metal oxide contains one or more metals selected from the group consisting of Ce, K, Mg, La and Y.

2. 2. The oxidative dehydrogenation catalyst according to claim 1, wherein the first coating layer is provided on the entire surface of the support.

3. 2. The oxidative dehydrogenation catalyst according to claim 1, wherein the second coating layer is provided on the entire surface of the first coating layer.

4. The zinc ferrite catalyst according to claim 1, wherein the zinc ferrite catalyst is represented by the following chemical formula 1: [Chemical formula 1] ZnFe ｘ O ｙ In the above Chemical Formula 1, x is 1 to 2.8; y is 1 to 6.

5. 2. The oxidative dehydrogenation catalyst of claim 1, wherein the content of the at least one metal selected from Ce, K, Mg, La, and Y is 0.05 wt % to 5 wt %, based on the total weight of the zinc ferrite catalyst.

6. 2. The oxidative dehydrogenation catalyst according to claim 1, wherein the support comprises at least one of alumina, silica, alumina-silica, silicon carbide, titania, and zirconia.

7. After coating the support with a first solution containing a metal oxide precursor, a first heat treatment step is performed to form a first coating layer; and a step of coating a second solution containing a zinc ferrite catalyst on the first coating layer, and then performing a second heat treatment to form a second coating layer; The metal oxide precursor contains one or more metals selected from Ce, K, Mg, La, and Y.

8. 8. The method for producing a catalyst for oxidative dehydrogenation reaction according to claim 7, wherein the zinc ferrite catalyst is represented by the following chemical formula 1: [Chemical formula 1] ZnFe ｘ O ｙ In the above Chemical Formula 1, x is 1 to 2.8; y is 1 to 6.

9. Providing a catalyst for oxidative dehydrogenation reaction according to any one of claims 1 to 6; and using the oxidative dehydrogenation catalyst in the oxidative dehydrogenation of butene to produce butadiene. A method for producing butadiene, comprising:

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