Catalyst, method for producing catalyst, and method for producing p-xylene

Abstract

To provide a novel catalyst that efficiently yields p-xylene through the cyclodehydrogenation reaction of diisobutylene.SOLUTION: A catalyst for the cyclodehydrogenation reaction of diisobutylene comprises a carrier and a support metal carried on the carrier, where the support metal contains platinum and tin, and 50% or more of platinum atoms in the support metal form a PtSn(1:1) crystal structure.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to a catalyst, a method for producing the catalyst, and a method for producing p-xylene. [Background technology]

[0002] p-Xylene is an industrially useful substance as a raw material for terephthalic acid, which is an intermediate raw material for polyester fibers and PET resins. Methods for producing p-xylene include, for example, a method for producing p-xylene from raw materials containing ethylene (Patent Document 1) and a method for producing p-xylene from biomass (Patent Document 2), and various methods for efficiently producing p-xylene are being investigated. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-79815 A [Patent Document 2] JP 2015-193647 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure aims to provide a novel catalyst capable of efficiently producing p-xylene by cyclodehydrogenation of diisobutylene, as well as a method for producing the catalyst and a method for producing p-xylene using the catalyst. [Means for solving the problem]

[0005] The present disclosure relates to, for example, the following [1] to [6]. [1] A catalyst for cyclodehydrogenation of diisobutylene, comprising: A carrier; A supported metal supported on the support; Including, The supported metal comprises platinum and tin; A catalyst in which 50% or more of the platinum atoms in the supported metal form a PtSn (1:1) crystal structure. [2] The catalyst according to [1], wherein the support comprises silica. [3] The catalyst according to [1] or [2], wherein the supported metal further contains a Group 13 element. [4] A method for producing the catalyst according to any one of [1] to [3], an impregnation step of impregnating the support with an aqueous solution containing a platinum source and a tin source; a freeze-drying step of freeze-drying the carrier impregnated with the aqueous solution; a reduction step of heating the carrier that has been subjected to the freeze-drying step under a reducing atmosphere to obtain the catalyst; A method for producing a catalyst comprising the steps of: [5] The method further includes a baking step of baking the carrier that has been subjected to the freeze-drying step, The method for producing a catalyst according to [4], wherein the reduction step is a step of heating the support that has been subjected to the calcination step in a reducing atmosphere to obtain the catalyst. [6] A method for producing p-xylene, comprising a step of contacting diisobutylene with the catalyst according to any one of [1] to [3] to obtain p-xylene. Effect of the Invention

[0006] According to the present disclosure, there is provided a novel catalyst capable of efficiently producing p-xylene by cyclodehydrogenation of diisobutylene. In addition, according to the present disclosure, there is provided a method for producing the catalyst, and a method for producing p-xylene using the catalyst. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Preferred embodiments of the present disclosure will now be described in detail.

[0008] <Catalyst> The catalyst of this embodiment includes a support and a supported metal supported on the support. In this embodiment, the supported metal contains platinum and tin, and 50% or more of the platinum atoms in the support metal form a PtSn (1:1) crystal structure.

[0009] The catalyst of the present embodiment is a catalyst that efficiently promotes the cyclization dehydrogenation reaction for obtaining p-xylene from diisobutylene, and can be said to be a catalyst for the cyclization dehydrogenation reaction of diisobutylene.

[0010] Conventionally, catalysts in which platinum and tin are supported on a carrier have been known as catalysts for the dehydrogenation reaction of hydrocarbons. However, according to the findings of the present inventors, the platinum-tin alloy formed on the carrier in the conventional catalyst has various crystal structures (e.g., Pt 3 Sn, Pt 2 Sn 3 , PtSn, etc.) are mixed, and Pt 3 In contrast, the inventors discovered that by forming an alloy mainly having a Pt:Sn=1:1 crystal structure on a support, a catalyst that efficiently promotes the cyclization dehydrogenation reaction to obtain p-xylene from isobutylene can be obtained.

[0011] That is, in the catalyst of this embodiment, 50% or more of the platinum atoms in the supported metal form a PtSn (1:1) crystal structure, and therefore the cyclization dehydrogenation reaction of obtaining p-xylene from isobutylene can be efficiently promoted.

[0012] The support is preferably an inorganic oxide support. The inorganic oxide support may be a support containing an inorganic oxide, or may be a support containing an inorganic oxide as a main component (for example, an inorganic oxide content of 90 mass% or more, preferably 95 mass% or more, more preferably 99 mass% or more).

[0013] Examples of inorganic oxides constituting the support include silica, alumina, magnesia, and composite oxides thereof (for example, silica alumina, magnesia alumina), etc. The support is preferably silica or magnesia alumina.

[0014] The carrier preferably contains silica from the viewpoint of suppressing side reactions in the cyclodehydrogenation reaction of diisobutylene and more efficiently obtaining p-xylene. From the viewpoint of obtaining the above-mentioned effect more significantly, the content of silica in the carrier may be, for example, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 99% by mass or more, or may be 100% by mass, based on the total amount of the carrier.

[0015] The supported metals include platinum and tin, and may further include a Group 13 element.

[0016] The platinum content (also referred to as the amount of supported platinum) may be, for example, 0.1 parts by mass or more relative to 100 parts by mass of the carrier, and from the viewpoint of further improving the activity as a catalyst for the cyclodehydrogenation reaction of diisobutylene, it may be 0.5 parts by mass or more, 1 part by mass or more, or 2 parts by mass or more. The platinum content may be, for example, 30 parts by mass or less relative to 100 parts by mass of the carrier, and from the viewpoint of suppressing aggregation of platinum and efficiently obtaining high catalytic activity, it may be 20 parts by mass or less, 10 parts by mass or less, or 5 parts by mass or less.

[0017] The tin content (also referred to as the amount of tin supported) may be, for example, 0.1 parts by mass or more relative to 100 parts by mass of the support, and from the viewpoint of further improving the activity as a catalyst for the cyclodehydrogenation reaction of diisobutylene, it may be 0.5 parts by mass or more, 1 part by mass or more, or 2 parts by mass or more. In addition, the tin content may be, for example, 30 parts by mass or less, 20 parts by mass or less, 10 parts by mass or less, or 5 parts by mass or less relative to 100 parts by mass of the support.

[0018] In the supported metal, the molar ratio (Pt / Sn) of platinum (Pt) to tin (Sn) may be, for example, 0.3 or more, and from the viewpoint of further improving the activity as a catalyst for the cyclization dehydrogenation reaction of diisobutylene, may be 0.5 or more, 0.8 or more, or 0.9 or more. The molar ratio (Pt / Sn) may be, for example, 3.0 or less, and from the viewpoint of further improving the activity as a catalyst for the cyclization dehydrogenation reaction of diisobutylene, may be 2.0 or less, 1.5 or less, or 1.2 or less.

[0019] The total amount of platinum and tin in the supported metal (the proportion of platinum and tin in the supported metal) may be, for example, 70 mass% or more based on the total amount of the supported metal, and from the viewpoint of obtaining the above-mentioned effect more significantly, it may be 80 mass% or more, 90 mass% or more, or 95 mass% or more, or may be 100 mass%.

[0020] When the supported metal further contains a Group 13 element, the proportion of the Group 13 element may be, for example, 30 mass % or less, 20 mass % or less, 10 mass % or less, or 5 mass % or less, based on the total amount of the supported metal.

[0021] Examples of Group 13 elements include aluminum (Al), gallium (Ga), indium (In), and thallium (Tl). Of these, indium is preferred from the viewpoint of making the cyclization dehydrogenation reaction of diisobutylene proceed more efficiently.

[0022] In the supported metal, the molar ratio of the Group 13 element (M) to platinum (Pt) may be, for example, 0.5 or less, 0.4 or less, 0.3 or less, or 0.25 or less, or may be zero.

[0023] The supported metal may further contain Group 2 elements (e.g., magnesium, calcium), Group 14 elements other than tin (e.g., germanium), etc. The preferred ranges of the contents of these elements are the same as the preferred ranges of the content of Group 13 elements.

[0024] In the supported metal, 50% or more of the platinum atoms form a PtSn (1:1) crystal structure. In this specification, the PtSn (1:1) crystal structure means a crystal structure composed of platinum atoms and tin atoms, in which the ratio of platinum atoms to tin atoms is 1:1.

[0025] The ratio of platinum atoms forming the PtSn (1:1) crystal structure is measured by X-ray diffraction spectroscopy in the following manner. (How to confirm the crystal structure) The peak areas of the PtSn(102) plane and the Pt3Sn(111) plane were obtained from the X-ray diffraction spectrum and calculated using the following formula. (Proportion of platinum atoms forming the PtSn(1:1) crystal structure) = 100 × peak area of ​​the PtSn(102) plane / (peak area of ​​the PtSn(102) plane + peak area of ​​the Pt3Sn(111) plane)

[0026] The catalyst of the present embodiment can be produced, for example, by the following production method.

[0027] <Catalyst manufacturing method> The production method of this embodiment includes an impregnation step of impregnating a support with an aqueous solution containing a platinum source and a tin source, a freeze-drying step of freeze-drying the support impregnated with the aqueous solution, and a reduction step of heating the support that has been subjected to the freeze-drying step in a reducing atmosphere to obtain a catalyst.

[0028] According to the production method of this embodiment, the catalyst of this embodiment having a PtSn (1:1) crystal structure can be produced efficiently.

[0029] The reason why the PtSn (1:1) crystal structure is formed in large amounts in the manufacturing method of this embodiment is believed to be as follows. In the freeze-drying process, an aqueous solution containing platinum and tin sources is frozen and the water is evaporated by sublimation, which is believed to improve the dispersibility of platinum and tin and facilitate the formation of the PtSn (1:1) crystal structure.

[0030] Each step of the manufacturing method of this embodiment will be described in detail below.

[0031] (Impregnation process) In the impregnation step, the support is impregnated with an aqueous solution containing a platinum source and a tin source.

[0032] The metal source (platinum source, tin source, indium source, etc.) in the aqueous solution may be, for example, a salt or complex containing a metal element (platinum, tin, indium, etc.). The salt may be, for example, an inorganic salt, an organic salt, or a hydrate thereof. The complex may be, for example, an alkoxide complex, an ammine complex, etc. The inorganic salt may be, for example, a sulfate, a nitrate, a chloride, a phosphate, a carbonate, etc. The organic salt may be, for example, an acetate, an oxalate, etc. The complex may be, for example, an alkoxide complex, an ammine complex, etc.

[0033] The platinum source may be any platinum compound that can be prepared as an aqueous solution. The platinum source may be used alone or in combination of two or more.

[0034] Examples of platinum sources include dinitrodiammineplatinum(II) (Pt(NO 2 ) 2 (NH 3 ) 2 ), chloroplatinic acid hexahydrate(IV)(H 2 PtCl 6 6H 2 O), tetraamminedichloroplatinum(II) (Pt(NH 3 ) 4 Cl 2 As a platinum source, dinitrodiammine platinum(II) (Pt(NO 2 ) 2 (NH 3 ) 2 ), tetraamminedichloroplatinum(II) (Pt(NH 3 ) 4 Cl 2 ), and dinitrodiammineplatinum(II) (Pt(NO 2 ) 2 (NH 3 ) 2 ) is more preferred.

[0035] The tin source may be any tin compound that can be prepared as an aqueous solution. The tin source may be used alone or in combination of two or more kinds.

[0036] Examples of tin sources include tin(II) chloride (SnCl 2 ), ammonium hexachlorostannate(IV) ((NH 4 ) 2 SnCl 6 ), ammonium hexafluorostannate(IV) ((NH 4 ) 2 SnF 6 ), Sodium Stannate Trihydrate(IV)(Na 2 SnO 3 6H 2 As a tin source, from the viewpoint of improving the dispersibility of tin, tin(II) chloride (SnCl 2 ), ammonium hexachlorostannate(IV) ((NH 4 ) 2 SnCl 6 ), ammonium hexafluorostannate(IV) ((NH 4 ) 2 SnF 6 ) is preferred.

[0037] The aqueous solution may contain a metal source other than the platinum source and the tin source, for example, the aqueous solution may further contain a metal compound containing a Group 13 element (e.g., an indium source).

[0038] The metal compound containing a Group 13 element may be any compound that can be prepared as an aqueous solution. The metal compound may be used alone or in combination of two or more kinds.

[0039] Indium sources include, for example, indium(III) nitrate n-hydrate (In(NO 3 ) 3 nH 2 O), indium(III) sulfate n-hydrate (In(NO 3 ) 3 nH 2O), indium(III) acetate (In(CH 3 COO) 3 ) etc.

[0040] The content of each metal source in the aqueous solution may be appropriately adjusted depending on the desired amount to be supported.

[0041] The method for impregnating the support with the aqueous solution is not particularly limited, and examples thereof include a method of immersing the support in the aqueous solution, a pore filling method, and the like.

[0042] (lyophilization process) In the freeze-drying step, the support impregnated with the aqueous solution is freeze-dried and, if necessary, further calcined to obtain a catalyst precursor.

[0043] In freeze-drying, a support impregnated with an aqueous solution is cooled to freeze the aqueous solution, and the support containing the frozen aqueous solution is held under reduced pressure to remove at least a portion of the water in the aqueous solution.

[0044] In freeze-drying, the cooling method for freezing the aqueous solution is not particularly limited, and examples of the cooling method include cooling with liquid nitrogen, cooling with a refrigerator, cooling with an aqueous solution containing dissolved sodium hydroxide, and cooling with ice water.

[0045] In the freeze-drying, the pressure reduction may be performed at a temperature at which the aqueous solution remains frozen. The temperature may be, for example, from -100°C to 10°C, or from -20°C to 0°C.

[0046] In the freeze-drying, the degree of pressure reduction is not particularly limited as long as the pressure reduction is sufficient to remove water from the frozen aqueous solution. The pressure may be, for example, 1 to 3000 Pa, or 1 to 1000 Pa.

[0047] In freeze-drying, at least a portion of the water in the aqueous solution is removed, preferably 80% or more, and more preferably 90% or more of the water in the aqueous solution is removed.

[0048] In freeze-drying, a part of the water in the aqueous solution may not be removed and may remain. For example, in freeze-drying, 1% or more of the water in the aqueous solution may remain, or 5% or more of the water may remain.

[0049] The freeze-drying time is not particularly limited as long as it is a time that allows the water in the aqueous solution to be removed as described above, and may be, for example, 12 to 240 hours, or 24 to 120 hours.

[0050] The carrier that has been freeze-dried may be subjected to the reduction step as it is, may be subjected to a high-temperature drying step and then to the reduction step, may be subjected to a baking step and then to the reduction step, or may be subjected to a high-temperature drying step and a baking step and then to the reduction step. That is, the production method of this embodiment may further include a high-temperature drying step, may further include a baking step, or may further include a high-temperature drying step and a baking step.

[0051] The high-temperature drying step is a step in which the carrier that has been subjected to freeze-drying is dried at a high temperature.

[0052] The drying temperature in the high-temperature drying step may be, for example, 50°C to 150°C, preferably 70°C to 120°C, and more preferably 80°C to 100°C.

[0053] The drying time in the high-temperature drying step is not particularly limited and may be, for example, 6 to 48 hours, and preferably 12 to 24 hours.

[0054] (Firing process) The calcination step is a step of calcining the support that has been subjected to the freeze-drying step (optionally, the support that has been further subjected to a high-temperature drying step). Hereinafter, the support that has been subjected to the calcination step is also referred to as a catalyst precursor.

[0055] In the firing step, the firing temperature may be, for example, 200° C. or higher, 250° C. or higher, 300° C. or higher, or 350° C. or higher. The firing temperature may be, for example, 700° C. or lower, 600° C. or lower, 500° C. or lower, or 450° C. or lower.

[0056] In the firing process, the firing time (the time for holding the carrier at the above-mentioned firing temperature) may be, for example, 1 hour or more, or 2 hours or more. Further, the firing time may be, for example, 10 hours or less, or 5 hours or less.

[0057] The firing may be carried out, for example, in an oxygen-containing gas atmosphere (for example, in an air atmosphere).

[0058] (Reduction process) In the reduction process, the carrier that has undergone the freeze-drying process (optionally, the carrier that has further undergone the high-temperature drying process and / or the firing process) is heated in a reducing atmosphere to obtain a catalyst.

[0059] In the reduction process, the reduction temperature may be, for example, 400°C or higher, and from the viewpoint of further promoting the formation of the PtSn crystal structure, it may be 450°C or higher or 500°C or higher. Further, the reduction temperature may be, for example, 1000°C or lower, and from the viewpoint of further suppressing the aggregation of the PtSn crystal structure, it may be 900°C or lower, 800°C or lower, or 700°C or lower.

[0060] In the reduction process, the reduction time (the time for holding the catalyst precursor at the above-mentioned reduction temperature) may be, for example, 0.3 hours or more, and from the viewpoint of further promoting the formation of the PtSn crystal structure, it may be 0.5 hours or more. Further, the reduction time may be, for example, 5 hours or less, and from the viewpoint of further suppressing the aggregation of the PtSn crystal structure, it may be 3 hours or less, 2 hours or less, or 1 hour or less.

[0061] The reduction process may be carried out, for example, in a hydrogen-containing gas atmosphere. The hydrogen-containing gas may be, for example, hydrogen gas or a mixed gas of hydrogen and an inert gas. The hydrogen content in the hydrogen-containing gas may be, for example, 50% by volume or more, and may also be 80% by volume or more, or 90% by volume or more. The inert gas may be, for example, nitrogen, helium, argon, etc.

[0062] <Method for producing p-xylene> The method for producing p-xylene of this embodiment includes a reaction step of contacting diisobutylene with the catalyst of this embodiment to obtain p-xylene by cyclization dehydrogenation reaction of diisobutylene.

[0063] As used herein, diisobutylene may be 2,4,4-trimethyl-1-pentene, 2,4,4-trimethyl-2-pentene, or a mixture thereof.

[0064] The method for producing p-xylene according to the present embodiment uses the above-mentioned catalyst, and therefore p-xylene can be efficiently produced from diisobutylene.

[0065] Diisobutylene can be obtained, for example, by the dimerization reaction of isobutene.

[0066] The reaction step may be a step of contacting a feedstock component containing diisobutylene with the catalyst of this embodiment.

[0067] The content of diisobutylene in the raw material components may be, for example, 50 mass% or more, 80 mass% or more, 90 mass% or more, or 95 mass% or more, or may be 100 mass%, based on the total amount of the raw material components.

[0068] The feedstock component may be, for example, a reaction product of the dimerization reaction of isobutene, and may further contain by-products in the dimerization reaction of isobutene (e.g., trimethylpentene isomers, dimethylhexene isomers, etc.) The feedstock component may also further contain hydrocarbons having a carbon number of 12 or less.

[0069] The reaction temperature of the cyclization dehydrogenation reaction (for example, the temperature inside a reactor described below) may be, for example, 450° C. or higher, and from the viewpoint of further promoting the dehydrogenation reaction, may be 480° C. or higher or 500° C. or higher. The reaction temperature of the cyclization dehydrogenation reaction may be, for example, 700° C. or lower, and from the viewpoint of further suppressing side reactions, may be 650° C. or lower or 550° C. or lower.

[0070] The reaction pressure of the cyclization dehydrogenation reaction (e.g., the pressure inside a reactor described below) may be, for example, 3.0 MPa-G or less, and from the viewpoint of further promoting the dehydrogenation reaction, it may be 1.0 MPa-G or less, 0.5 MPa-G or less, or 0.1 MPa-G or less.

[0071] The cyclization dehydrogenation reaction may be carried out, for example, by using a reactor filled with the present embodiment catalyst and passing the raw material components through the reactor. As the reactor, various reactors used in gas phase reactions using solid catalysts can be used. As the reactor, for example, a fixed bed type reactor, a radial flow type reactor, a tubular type reactor, etc. can be mentioned.

[0072] When the cyclization dehydrogenation reaction is carried out in a continuous reaction system in which the raw material gas (raw material gas) is continuously supplied, the weight hourly space velocity (WHSV) is, for example, 0.1 h -1 may be more than 0.5h -1 or more than 0.8 hours -1 The weight hourly space velocity (WHSV) may be, for example, 10.0 h -1 may be less than 5.0h -1 Below, 3.0h -1 Less than or equal to 2.0h -1 In this specification, the weight hourly space velocity refers to the ratio (F / W) of the feed rate (F) (feed amount / time) of the raw material gas to the mass (W) of the catalyst.

[0073] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. EXAMPLES

[0074] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0075] Example 1 (1) Preparation of Catalyst A-1 Catalyst A-1 was prepared in the following manner. 10 g of CAriACT G-6 (silica carrier) manufactured by Fuji Silysia was prepared as a carrier. Dinitrodiammine platinum and tin chloride were dissolved in 16 mL of ion-exchanged water so that the amount of Pt supported on the carrier was 3 mass% and the atomic ratio of Pt to Sn was 1:1 to obtain a metal source solution. The metal source solution was dripped onto the carrier by the pore-filling method to impregnate it and then sealed in a plastic film. This was left at room temperature for 16 hours, then freeze-dried at 0°C under reduced pressure for 24 hours, and further dried at 90°C for 16 hours. The obtained powder was calcined in air at 400°C for 1 hour, and then reduced in a hydrogen stream at 700°C for 1 hour to obtain catalyst A-1. (2) Crystal structure analysis The crystal structure of the obtained catalyst A-1 was analyzed by the following method. An X-ray diffraction pattern was obtained using a Rigaku MiniFlex700+D / teX Ultra with Cu Kα as the X-ray source. In the obtained X-ray diffraction pattern, only peaks derived from PtSn and Pt3Sn were observed as Pt-containing crystal structures. As a result of peak analysis, it was confirmed that 84% of the platinum atoms in catalyst A-1 formed a PtSn (1:1) crystal structure. (3) Production of p-xylene Using catalyst A-1, p-xylene was produced by the following method. A reaction test was carried out by simultaneously flowing 0.25 g / h of Tokyo Chemical Industry Co., Ltd. diisobutylene and 6.8 mL / min of nitrogen into a reaction tube filled with 0.25 g of catalyst A-1 at a reaction temperature of 530°C and a reaction pressure of 30 kPa-G. The paraxylene yield after 2 hours from the start of the reaction is shown in Table 1.

[0076] Example 2 (1) Preparation of Catalyst A-2 The tin source was ammonium hexachlorostannate(IV) ((NH 4 ) 2 SnCl 6 ), catalyst A-2 was obtained in the same manner as in Example 1. When the crystal structure of the obtained catalyst A-2 was analyzed in the same manner as in Example 1, it was confirmed that 75% of platinum atoms in catalyst A-2 formed a PtSn(1:1) crystal structure. (2) Production of p-xylene Except for using Catalyst A-2 instead of Catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0077] Example 3 (1) Preparation of Catalyst A-3 The tin source was ammonium hexachlorostannate(IV) ((NH 4 ) 2 SnCl 6 ) and the reduction temperature was changed from 700° C. to 550° C., and the same procedure as in Example 1 was used to obtain catalyst A-3. When the crystal structure of the obtained catalyst A-3 was analyzed in the same manner as in Example 1, it was confirmed that 91% of platinum atoms in catalyst A-3 formed a PtSn (1:1) crystal structure. (2) Production of p-xylene Except for using Catalyst A-3 instead of Catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0078] Example 4 (1) Preparation of Catalyst A-4 The tin source was ammonium hexachlorostannate(IV) ((NH 4 ) 2 SnCl 6 ) and the reduction temperature was changed from 700° C. to 500° C., and the same procedure as in Example 1 was used to obtain catalyst A-4. When the crystal structure of the obtained catalyst A-4 was analyzed in the same manner as in Example 1, it was confirmed that 85% of the platinum atoms in catalyst A-4 formed a PtSn (1:1) crystal structure. (2) Production of p-xylene Except for using Catalyst A-4 instead of Catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0079] Example 5 (1) Preparation of Catalyst A-5 The tin source was prepared from ammonium hexafluorostannate(IV) ((NH4 ) 2 SnF 6 ) and the reduction temperature was changed from 700° C. to 550° C., and the same procedure as in Example 1 was used to obtain catalyst A-5. When the crystal structure of the obtained catalyst A-5 was analyzed in the same manner as in Example 1, it was confirmed that 89% of the platinum atoms in catalyst A-5 formed a PtSn (1:1) crystal structure. (2) Production of p-xylene Except for using Catalyst A-5 instead of Catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0080] Example 6 (1) Preparation of Catalyst A-6 The tin source was converted from tin chloride to sodium stannate (IV) (Na 2 SnO 3 ) and the reduction temperature was changed from 700° C. to 550° C., and the same procedure as in Example 1 was used to obtain catalyst A-6. When the crystal structure of the obtained catalyst A-6 was analyzed in the same manner as in Example 1, it was confirmed that 63% of platinum atoms in catalyst A-6 formed a PtSn (1:1) crystal structure. (2) Production of p-xylene Except for using Catalyst A-6 instead of Catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0081] Example 7 (1) Preparation of Catalyst A-7 The tin source was ammonium hexachlorostannate(IV) ((NH 4 ) 2 SnCl 6 ), the atomic ratio of Pt to Sn (Pt:Sn) was changed to 1.25:1, and the reduction temperature was changed from 700°C to 550°C, and the same procedure was followed to obtain catalyst A-7. When the crystal structure of the obtained catalyst A-7 was analyzed in the same manner as in Example 1, it was confirmed that 73% of the platinum atoms in catalyst A-7 formed a PtSn (1:1) crystal structure. (2) Production of p-xylene Except for using Catalyst A-7 instead of Catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0082] Example 8 (1) Preparation of Catalyst A-8 The tin source was ammonium hexachlorostannate(IV) ((NH 4 ) 2 SnCl 6 ), the atomic ratio of Pt to Sn (Pt:Sn) was changed to 0.83:1, and the reduction temperature was changed from 700°C to 550°C, and the same procedure was followed to obtain catalyst A-8. When the crystal structure of the obtained catalyst A-8 was analyzed in the same manner as in Example 1, it was confirmed that 94% of the platinum atoms in catalyst A-8 formed a PtSn (1:1) crystal structure. (2) Production of p-xylene Except for using Catalyst A-8 instead of Catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0083] Example 9 (1) Preparation of Catalyst A-9 The tin source was ammonium hexachlorostannate(IV) ((NH 4 ) 2 SnCl 6 ), calcination in air was not performed, and the reduction temperature was changed from 700° C. to 550° C., and the same procedure as in Example 1 was used to obtain catalyst A-9. When the crystal structure of the obtained catalyst A-9 was analyzed in the same manner as in Example 1, it was confirmed that 80% of the platinum atoms in catalyst A-9 formed a PtSn (1:1) crystal structure. (2) Production of p-xylene Except for using Catalyst A-9 instead of Catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0084] Example 10 (1) Preparation of Catalyst A-10 The tin source was ammonium hexachlorostannate(IV) ((NH 4 ) 2 SnCl 6 ), the calcination temperature was changed from 400°C to 200°C, and the reduction temperature was changed from 700°C to 550°C, and the same procedure was followed to obtain catalyst A-10. When the crystal structure of the obtained catalyst A-10 was analyzed in the same manner as in Example 1, it was confirmed that 86% of the platinum atoms in catalyst A-10 formed a PtSn (1:1) crystal structure. (2) Production of p-xylene Except for using Catalyst A-10 instead of Catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0085] Example 11 (1) Preparation of Catalyst A-11 As a support, 10 g of CALiACT G-6 (silica support) manufactured by Fuji Silysia Chemical Ltd. was prepared. A platinum source solution was prepared by dissolving dinitrodiammine platinum in 16 mL of ion-exchanged water so that the amount of Pt supported on the support was 3 mass %. The support was then impregnated with the metal source solution by the pore-filling method and sealed in a plastic film. This was left at room temperature for 16 hours, then freeze-dried at 0°C under reduced pressure for 24 hours, and further dried at 90°C for 16 hours. The resulting powder was calcined in air at 400°C for 1 hour, and then reduced in a hydrogen stream at 300°C for 1 hour to obtain catalyst precursor A-11. In addition, 10 g of catalyst precursor A-11 was prepared, and ammonium hexachlorostannate (IV) ((NH 4 ) 2 SnCl 6) was dissolved in 16 mL of ion-exchanged water to prepare a tin source solution. The support was impregnated with the metal source solution by the pore-filling method, and then sealed in a plastic film. The support was left at room temperature for 16 hours, then freeze-dried at 0°C under reduced pressure for 24 hours, and further dried at 90°C for 16 hours. The obtained powder was calcined in air at 400°C for 1 hour, and then reduced in a hydrogen stream at 550°C for 1 hour to obtain catalyst A-11. The crystal structure of the obtained catalyst A-11 was analyzed by the same method as in Example 1, and it was confirmed that 83% of the platinum atoms in catalyst A-11 formed a PtSn (1:1) crystal structure. (2) Production of p-xylene Except for using Catalyst A-11 instead of Catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0086] Example 12 (1) Preparation of Catalyst A-12 The tin source was ammonium hexachlorostannate(IV) ((NH 4 ) 2 SnCl 6 ) to ammonium hexafluorostannate(IV) ((NH 4 ) 2 SnF 6 ), catalyst A-12 was obtained in the same manner as in Example 11. The crystal structure of the obtained catalyst A-12 was analyzed in the same manner as in Example 1, and it was confirmed that 89% of platinum atoms in the catalyst A-12 formed a PtSn(1:1) crystal structure. (2) Production of p-xylene Except for using Catalyst A-12 instead of Catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0087] Example 13 (1) Preparation of Catalyst A-13 The tin source was ammonium hexachlorostannate(IV) ((NH 4 ) 2 SnCl 6), the amount of Pt supported on the carrier was changed from 3 mass% to 5 mass%, and the reduction temperature was changed from 700 ° C. to 550 ° C., and the catalyst A-13 was obtained in the same manner as in Example 1. When the crystal structure of the obtained catalyst A-13 was analyzed in the same manner as in Example 1, it was confirmed that 88% of the platinum atoms in the catalyst A-13 formed a PtSn (1:1) crystal structure. (2) Production of p-xylene Except for using Catalyst A-13 instead of Catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0088] Example 14 (1) Preparation of Catalyst A-14 Indium nitrate trihydrate (In(NO 3 ) 3 3H 2 O) was prepared. The tin source was ammonium hexachlorostannate(IV) ((NH 4 ) 2 SnCl 6 ), and an In source was added to the metal source solution so that the atomic ratio of Pt, Sn, and In (Pt:Sn:In) became 1:0.8:0.2, and catalyst A-14 was obtained in the same manner as in Example 1. When the crystal structure of the obtained catalyst A-14 was analyzed in the same manner as in Example 1, it was confirmed that 95% of platinum atoms in catalyst A-14 formed a PtSn (1:1) crystal structure. (2) Production of p-xylene Except for using Catalyst A-14 instead of Catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0089] Example 15 (1) Preparation of Catalyst A-15 Ammonium hexafluorogermanate ((NH 4 ) 2 GeF 6 ) was prepared. The tin source was ammonium hexachlorostannate(IV) ((NH4 ) 2 SnCl 6 ), a Ge source was added to the metal source solution so that the atomic ratio of Pt, Sn, and Ge (Pt:Sn:Ge) became 1:0.8:0.2, and the reduction temperature was changed from 700° C. to 550° C., and a catalyst A-15 was obtained in the same manner as in Example 1. When the crystal structure of the obtained catalyst A-15 was analyzed in the same manner as in Example 1, it was confirmed that 65% of the platinum atoms in the catalyst A-15 formed a PtSn (1:1) crystal structure. (2) Production of p-xylene Except for using Catalyst A-15 instead of Catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0090] (Example 16) (1) Preparation of Catalyst A-16 Magnesium nitrate hexahydrate (Mg(NO) 3 ) 3 6H 2 O) was prepared. The tin source was ammonium hexachlorostannate(IV) ((NH 4 ) 2 SnCl 6 ), and a Mg source was added to the metal source solution so that the atomic ratio of Pt, Sn, and Mg (Pt:Sn:Mg) became 1:1:5, and a catalyst A-16 was obtained in the same manner as in Example 1. When the crystal structure of the obtained catalyst A-16 was analyzed in the same manner as in Example 1, it was confirmed that 92% of the platinum atoms in the catalyst A-16 formed a PtSn (1:1) crystal structure. (2) Production of p-xylene Except for using Catalyst A-16 instead of Catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0091] (Example 17) (1) Preparation of Catalyst A-17 Calcium nitrate tetrahydrate (Ca(NO) 3 ) 3 4H 2O) was prepared. The tin source was ammonium hexachlorostannate(IV) ((NH 4 ) 2 SnCl 6 ), and a Ca source was added to the metal source solution so that the atomic ratio of Pt, Sn, and Ca (Pt:Sn:Ca) became 1:1:5, and catalyst A-17 was obtained in the same manner as in Example 1. When the crystal structure of the obtained catalyst A-17 was analyzed in the same manner as in Example 1, it was confirmed that 91% of platinum atoms in catalyst A-17 formed a PtSn (1:1) crystal structure. (2) Production of p-xylene Except for using Catalyst A-17 instead of Catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0092] Comparative Example 1 (1) Production of Catalyst X-1 Catalyst X-1 was obtained in the same manner as in Example 1, except that the atomic ratio of Pt to Sn (Pt:Sn) was changed to 3:1. When the crystal structure of the obtained catalyst X-1 was analyzed in the same manner as in Example 1, no peak derived from PtSn was observed, and only a peak derived from Pt3Sn was observed. From this, it was confirmed that the platinum atoms in catalyst X-1 did not form a PtSn (1:1) crystal structure. (2) Production of p-xylene Except for using Catalyst X-1 instead of Catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0093] Comparative Example 2 (1) Production of Catalyst X-2 Catalyst X-2 was obtained in the same manner as in Example 1, except that freeze-drying was not performed, and the catalyst was dried at 90° C. for 16 hours after impregnation with the metal source solution. When the crystal structure of the obtained catalyst X-2 was analyzed in the same manner as in Example 1, no peak derived from PtSn was observed, and only a peak derived from Pt3Sn was observed. This confirmed that the platinum atoms in catalyst X-2 did not form a PtSn (1:1) crystal structure. (2) Production of p-xylene Except for using catalyst X-2 instead of catalyst A-1, p-xylene was produced in the same manner as in Example 1. The results are shown in Table 1.

[0094] [Table 1]

[0095] In the table, "raw material conversion rate (%)" indicates the conversion rate (%) of diisobutylene 2 hours after the start of the reaction, and "PX yield (%)" indicates the yield (%) of paraxylene 2 hours after the start of the reaction. "PtSn (%)" indicates the ratio (%) of platinum atoms in the catalyst that form a PtSn (1:1) crystal structure. "Sn1" in the Sn source indicates tin(II) chloride (SnCl 2 ), and "Sn2" is ammonium hexachlorostannate(IV) ((NH 4 ) 2 SnCl 6 ), and "Sn3" is ammonium hexafluorostannate(IV) ((NH 4 ) 2 SnF 6 ) and "Sn4" sodium stannate(IV) (Na 2 SnO 3 In addition, "ratio Pt / Sn" indicates the molar ratio of platinum atoms to tin atoms in the catalyst, and "Pt amount (mass %)" indicates the content of platinum atoms in the catalyst.

Claims

1. A catalyst for cyclodehydrogenation of diisobutylene, comprising: A carrier; A supported metal supported on the support; Including, The supported metal comprises platinum and tin; A catalyst in which 50% or more of the platinum atoms in the supported metal form a PtSn (1:1) crystal structure.

2. The catalyst of claim 1 , wherein the support comprises silica.

3. 10. The catalyst of claim 1, wherein the supported metal further comprises a Group 13 element.

4. A method for producing the catalyst according to any one of claims 1 to 3, comprising the steps of: an impregnation step of impregnating the support with an aqueous solution containing a platinum source and a tin source; a freeze-drying step of freeze-drying the carrier impregnated with the aqueous solution; a reduction step of heating the carrier that has been subjected to the freeze-drying step under a reducing atmosphere to obtain the catalyst; A method for producing a catalyst comprising the steps of:

5. The method further includes a baking step of baking the carrier that has been subjected to the freeze-drying step, The method for producing a catalyst according to claim 4, wherein the reduction step is a step of heating the support that has been subjected to the calcination step in a reducing atmosphere to obtain the catalyst.

6. A method for producing p-xylene, comprising the step of contacting diisobutylene with the catalyst according to any one of claims 1 to 3 to obtain p-xylene.

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