Mesoporous bifunctional catalyst, preparation method and application thereof, and preparation method of dicyclohexylbenzene

Abstract

The present invention relates to the field of catalyst technology, and more specifically to a mesoporous bifunctional catalyst, its preparation method, and application, and a method for preparing dicyclohexylbenzene. The mesoporous bifunctional catalyst has an average pore diameter of 5 nanometers or greater and contains at least 100 μmol / g of strong acid centers. The mesoporous bifunctional catalyst comprises: 10-30% by weight of an acidic silica-alumina composite; 50-65% by weight of an MCM-41 molecular sieve; 5-10% by weight of a solid superacid; and 1-15% by weight of a hydrogenation metal component. The mesoporous bifunctional catalyst has high catalytic activity and is used to prepare dicyclohexylbenzene, achieving high dicyclohexylbenzene yields and low reaction energy consumption.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts, and in particular to a mesoporous bifunctional catalyst, a preparation method and application thereof, and a preparation method of dicyclohexylbenzene. Background Art

[0002] Dicyclohexylbenzene mainly includes three isomers: o-, m-, and p-, and is the main component of hydrogenated terphenyl, a high-temperature heat transfer oil. Hydrogenated terphenyl heat transfer oil is the most widely used product among synthetic heat transfer oils. It has excellent uses in high-temperature fields such as polymerization reactions and distillation separations, and can provide good heat conduction effects. Due to its good high-temperature stability, low toxicity, and strong antioxidant capacity, hydrogenated terphenyl has become increasingly widely used in the market. In recent years, with the continuous upgrading of production capacity in the petrochemical industry, existing heat transfer oils can no longer meet demand, and the demand for such heat transfer oils in emerging industries such as photovoltaic power generation and energy storage has also increased significantly. Therefore, it is of great significance to develop an efficient production technology for hydrogenated terphenyl heat transfer oil.

[0003] Traditional hydrogenated terphenyl production technology uses benzene as a raw material, undergoing dehydrogenation and condensation at temperatures exceeding 800°C to produce biphenyl, with a small amount of crude terphenyl as a by-product. After separating this terphenyl from the biphenyl, it is partially hydrogenated over a catalyst to produce hydrogenated terphenyl. This method requires very high reaction temperatures and yields relatively low yields. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems of high energy consumption and low yield of hydrogenated terphenyl in the prior art, and to provide a mesoporous bifunctional catalyst with high catalytic activity and a preparation method thereof, as well as a preparation method of dicyclohexylbenzene.

[0005] To achieve the above objectives, the first aspect of the present invention provides a mesoporous bifunctional catalyst having an average pore diameter of 5 nanometers or more and a number of strong acid centers of 100 μmol / g or more. The mesoporous bifunctional catalyst comprises: 10-30 weight percent of an acidic silica-alumina composite; 50-70 weight percent of an MCM-41 molecular sieve; 5-10 weight percent of a solid superacid; and 1-15 weight percent of a hydrogenation metal component.

[0006] A second aspect of the present invention provides a method for preparing the mesoporous bifunctional catalyst of the present invention, the method comprising:

[0007] a. Preparation of acidic silica-alumina composite;

[0008] b. The hydrogenation metal component is loaded on the acidic silica - alumina composite to obtain a component;

[0009] c. The solid superacid is loaded on MCM-41 molecular sieve to obtain component II;

[0010] d. Mix and knead component one and component two and form them.

[0011] A third aspect of the present invention provides a use of the mesoporous bifunctional catalyst of the present invention in the preparation of dicyclohexylbenzene.

[0012] A fourth aspect of the present invention provides a method for preparing dicyclohexylbenzene, comprising: subjecting benzene and cyclohexylbenzene to a contact reaction in the presence of the mesoporous bifunctional catalyst of the present invention.

[0013] The mesoporous bifunctional catalyst of the present invention has high catalytic activity and is used for preparing dicyclohexylbenzene, and has the advantages of high dicyclohexylbenzene yield and low reaction energy consumption.

[0014] The present invention adopts benzene and cyclohexylbenzene as raw materials and uses the mesoporous bifunctional catalyst of the present invention to significantly improve the yield of dicyclohexylbenzene product through hydrogenation alkylation, thereby obtaining dicyclohexylbenzene with a higher yield and low energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 1 is the pore size distribution diagram of the catalyst prepared in Examples 1-6. DETAILED DESCRIPTION

[0016] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0017] A first aspect of the present invention provides a mesoporous bifunctional catalyst having an average pore diameter of 5 nanometers or more and a strong acid center count of 100 μmol / g or more. The mesoporous bifunctional catalyst comprises: 10-30 weight percent of an acidic silica-alumina composite; 50-70 weight percent of an MCM-41 molecular sieve; 5-10 weight percent of a solid superacid; and 1-15 weight percent of a hydrogenation metal component.

[0018] According to a preferred embodiment of the present invention, the average pore diameter of the mesoporous bifunctional catalyst is 5-10 nanometers; thereby, it is beneficial to increase the yield of dicyclohexylbenzene and reduce energy consumption.

[0019] According to a preferred embodiment of the present invention, the amount of strong acid centers is 100-300 μmol / g.

[0020] According to a preferred embodiment of the present invention, the mesoporous bifunctional catalyst contains: 20-28 weight percent of an acidic silica-alumina composite; 55-65 weight percent of an MCM-41 molecular sieve; 6-9 weight percent of a solid superacid; and 2-11 weight percent of a hydrogenation metal component; thereby helping to increase the yield of dicyclohexylbenzene and reduce energy consumption.

[0021] According to a preferred embodiment of the present invention, the molar ratio of alumina to silica in the acidic silica-alumina composite is 1:1 to 1:5, which is beneficial to increasing the yield of dicyclohexylbenzene and reducing energy consumption.

[0022] In the present invention, there is no particular limitation on the solid superacid, and it can be any conventional solid superacid in the art. Preferably, the solid superacid is selected from one or more of zirconium solid acid, titanium solid acid and iron solid acid, more preferably zirconium solid acid; this is beneficial to increasing the yield of dicyclohexylbenzene and reducing energy consumption.

[0023] In the present invention, there is no particular limitation on the hydrogenation metal component, which may be a conventional hydrogenation metal component in the art. Preferably, the hydrogenation metal component element is selected from at least one of Ru, Ni, Co, Mo and W, preferably including at least one of Ru and Ni.

[0024] The catalysts having the aforementioned properties of the present invention can achieve the purpose of the present invention. There are no special requirements for their preparation methods. According to a preferred embodiment of the present invention, the preparation method of the mesoporous bifunctional catalyst comprises:

[0025] a. Preparation of acidic silica-alumina composite;

[0026] b. The hydrogenation metal component is loaded on the acidic silica - alumina composite to obtain a component;

[0027] c. The solid superacid is loaded on MCM-41 molecular sieve to obtain component II;

[0028] d. Mix and knead component one and component two and form them.

[0029] In step a of the present invention, the preparation method of the acidic silica-alumina composite can be a precipitation-impregnation method, a sol-gel method or a grafting method well known to those skilled in the art.

[0030] Step a comprises: mixing a silicon source, an aluminum source and a nitrogen-containing compound for reaction, drying, performing a first calcination, performing ammonium exchange, and then drying and performing a second calcination to obtain an acidic silicon oxide-aluminum oxide composite.

[0031] According to a preferred embodiment of the present invention, in step a, a silicon source and an aluminum source are added to water in proportion to form a mixed solution, the mixed solution is mixed with a nitrogen-containing compound to react, and then filtered, washed, dried at 100-150°C for 5-24 hours, and calcined at 550-950°C for 3-8 hours; subsequently, the calcined sample is exchanged with an ammonium salt solution at 40-100°C for 1-24 hours, washed with deionized water, dried at 100-150°C for 5-24 hours, and calcined at 450-650°C for 3-8 hours to prepare an acidic silicon oxide-aluminum oxide composite.

[0032] According to a preferred embodiment of the present invention, the silicon source is calculated as silicon dioxide, the aluminum source is calculated as aluminum oxide, and the mass ratio of the silicon source, aluminum source, nitrogen-containing compound, and water is 1:0.5-3:2-8:5-20. The amount of water used includes water introduced by the silicon source, aluminum source, etc.

[0033] Preferably, the reaction conditions of step a include: temperature of 0-100° C. and time of 5-24 hours.

[0034] According to a preferred embodiment of the present invention, the nitrogen-containing compound is selected from urea and / or ammonia water.

[0035] According to a preferred embodiment of the present invention, when the nitrogen-containing compound is ammonia water, ammonia water is added to adjust the pH value so that the mixed solution is neutral.

[0036] According to a preferred embodiment of the present invention, the ammonium salt solution includes an aqueous solution prepared by mixing one or a combination of any two or more of ammonium nitrate, ammonium chloride, ammonium sulfate, and ammonium oxalate with deionized water.

[0037] Step b comprises: loading the hydrogenation metal component into the acidic silicon oxide-alumina composite in the form of a salt solution, and then drying, third calcining, and reducing to obtain component one.

[0038] In the present invention, the hydrogenation component can be loaded onto the silica-alumina composite in the form of a salt solution by conventional techniques in the art, such as the equal volume impregnation method and the excess solution impregnation method well known to those skilled in the art.

[0039] According to a preferred embodiment of the present invention, the silicon oxide-aluminum oxide composite is loaded with the hydrogenation metal component salt solution and then dried using conventional methods in the art, such as drying at 100-150° C. for 5-24 hours.

[0040] According to a preferred embodiment of the present invention, in step b, the third calcination condition includes: calcination at 450-650° C. for 3-8 hours.

[0041] According to a preferred embodiment of the present invention, in step b, the reduction conditions include: reduction under a hydrogen atmosphere, a reduction temperature of 100-500°C, a reduction time of 0.5-12 hours, and a hydrogen volume space velocity of 100-600h -1 .

[0042] According to a preferred embodiment of the present invention, step c comprises: loading the soluble salt of the solid superacid on the MCM-41 molecular sieve under alkaline conditions, contacting with a sulfuric acid aqueous solution after drying, and then drying and calcining for the fourth time to obtain component two.

[0043] According to a preferred embodiment of the present invention, preferably, step c comprises: placing the MCM-41 molecular sieve in an aqueous solution of a soluble compound of the solid superacid, adding aqueous ammonia at room temperature to precipitate it, then filtering and washing, drying at room temperature and pressure for 1-24 hours, and drying at 100-150°C for 5-24 hours; then contacting with an aqueous sulfuric acid solution, drying at room temperature and pressure for 1-24 hours, and drying at 100-150°C for 5-24 hours, and fourth calcining to obtain component two.

[0044] According to the present invention, the concentration of the aqueous sulfuric acid solution is preferably 5-20% by weight. During use, for example, 98% by weight concentrated sulfuric acid can be added with water for preparation.

[0045] According to a preferred embodiment of the present invention, in step c, the fourth calcination condition includes: calcination at 450-650° C. for 3-8 hours.

[0046] According to a preferred embodiment of the present invention, the soluble compound of the solid superacid is selected from at least one of zirconium acetate, titanium chloride and ferric nitrate.

[0047] In the present invention, in step c, the contact with the aqueous sulfuric acid solution can be carried out by using an equal volume impregnation method, an excess solution impregnation method, etc., which are well known to those skilled in the art.

[0048] Step d comprises: kneading component one and component two in a certain proportion, and forming the mixture through mechanical stamping to prepare particles.

[0049] The present invention has no special requirements on the morphology of the catalyst, and the catalyst can be prepared into a specific shape according to actual needs.

[0050] A third aspect of the present invention provides a use of the mesoporous bifunctional catalyst of the present invention in the preparation of dicyclohexylbenzene.

[0051] A fourth aspect of the present invention provides a method for preparing dicyclohexylbenzene, the method comprising:

[0052] Benzene and cyclohexylbenzene are contacted and reacted in the presence of the mesoporous bifunctional catalyst of the present invention. Using the mesoporous bifunctional catalyst of the present invention, the yield of dicyclohexylbenzene product can be significantly increased through hydroalkylation, resulting in a high yield of dicyclohexylbenzene with low energy consumption.

[0053] According to a preferred embodiment of the present invention, the weight ratio of benzene to cyclohexylbenzene is 1:5 to 1:10, which is beneficial to increasing the yield of dicyclohexylbenzene and reducing energy consumption.

[0054] According to a preferred embodiment of the present invention, the conditions of the contact reaction include: a reaction temperature of 120 to 230° C., preferably 150 to 210° C.; a reaction pressure of 0.6 to 2.0 MPa, preferably 0.8 to 1.5 MPa; this is conducive to increasing the yield of dicyclohexylbenzene and reducing energy consumption.

[0055] According to a preferred embodiment of the present invention, the molar ratio of benzene to hydrogen is 2 to 6, preferably 2.5 to 4; the total mass space velocity of benzene and cyclohexylbenzene is 1.6 to 3.0 h -1 , preferably 2.0 to 25 hours -1 ; This is beneficial to increasing the yield of dicyclohexylbenzene and reducing energy consumption.

[0056] The present invention will be described in detail below through examples.

[0057] In the following examples, the pore size of the catalyst was obtained by low-temperature nitrogen physical adsorption, which is a conventional molecular sieve pore volume analysis method.

[0058] In the following examples, the number of strong acid centers in the catalyst was characterized by pyridine infrared acidity test. The test method includes: using an infrared spectrometer to measure the acidity of the sample by pyridine infrared. The sample was pressed into a tablet and placed in an infrared vacuum cell at 400 ° C and 10 -3 Pyridine adsorption spectra were collected after desorption at 200℃, 300℃ and 400℃, with the acquisition range of 1300-4000cm -1 The acidity of samples B and L is determined by the IR spectra at 1540 and 1450 cm -1 The integral intensity of the absorption peak near the α-D-type ... -1 , εL=2.22cm / μmol -1 .

[0059] The composition of the catalyst is calculated from the preparation ratio.

[0060] In Example 1-7, the hydroalkylation reaction method includes the following steps: preparing a mixture of benzene and cyclohexylbenzene in a mass ratio of 1:5, and the total mass space velocity of benzene and cyclohexylbenzene is 2.0h -1, the molar ratio of benzene to hydrogen feed is 5; the reaction temperature is 180°C, and the reaction pressure is 0.8 MPa.

[0061] Example 1

[0062] a. Take 60 grams of silica, add it to 500 grams of deionized water, and stir thoroughly to form a suspension. Then add 125 grams of aluminum nitrate nonahydrate and stir at 60°C for 10 minutes; then add 280 grams of urea and continue heating at 80°C for 12 hours; filter, wash with deionized water, dry at 120°C for 12 hours, and calcine at 600°C for 5 hours; then, exchange the calcined sample with 2M ammonium chloride solution at 90°C for 12 hours, wash with deionized water, dry at 120°C for 12 hours, and calcine at 550°C for 6 hours. An acidic silica-alumina composite with a molar ratio of aluminum oxide to silica of 1:3 is obtained;

[0063] b. Take 50 g of silica-alumina composite, loaded with 4 g of Ru, and impregnated with ruthenium chloride salt in equal volumes, dried at 120 ° C for 12 hours, and calcined at 550 ° C for 5 hours; the resulting sample was reduced at 300 ° C for 3 hours and a hydrogen volume space velocity of 300h -1 , get component one;

[0064] c. Take 100 grams of MCM-41 molecular sieve, add it to 500 grams of deionized water, stir thoroughly to form a suspension; then add 20 grams of zirconium acetate, add 50 milliliters of 35% by weight ammonia water, continue heating at 80°C for 12 hours, then filter, wash with deionized water and dry at 120°C for 12 hours. Subsequently, take 12 grams of concentrated sulfuric acid (98% by weight), dissolve it in 100 milliliters of deionized water, impregnate the dried MCM-41, dry it at room temperature and pressure for 12 hours, dry it at 100-150°C for 12 hours, and calcine it at 500°C for 6 hours to obtain component two;

[0065] d. Take 30 g of component one and 70 g of component two, knead and mix, and then mechanically stamp to form a flaky granular catalyst, referred to as catalyst A. Catalyst A consists of 27.8 wt% of an acidic silica-alumina complex; 61.7 wt% of an MCM-41 molecular sieve; 8.3 wt% of a solid superacid; and 2.2 wt% of a hydrogenation metal component.

[0066] Catalyst A was subjected to low-temperature nitrogen physical adsorption analysis and pyridine infrared acidity characterization. The results are shown in Table 1 and Figure 1 .

[0067] Catalyst A was subjected to hydroalkylation reaction evaluation, and the reaction results are shown in Table 1.

[0068] Example 2

[0069] a. Take 100 g of 40 wt% silica sol, add 108 g of aluminum chloride hexahydrate with sufficient stirring, then adjust the pH to neutral with ammonia, and continue stirring for 12 hours; filter, wash with deionized water and dry at 120 ° C for 12 hours, calcined at 600 ° C for 5 hours; then, the calcined sample was exchanged with 2M ammonium chloride solution at 90 ° C for 12 hours, washed with deionized water, dried at 120 ° C for 12 hours, and calcined at 550 ° C for 6 hours; to obtain an acidic silica-alumina composite with a ratio of aluminum oxide to silicon oxide of 1:3;

[0070] b. Take 50 g of the above silica - alumina composite, loaded with 15 g of Ni, and impregnated with an equal volume of nickel nitrate, dried at 120 ° C for 12 hours, and calcined at 550 ° C for 5 hours; the resulting sample was reduced at 450 ° C for 3 hours and a hydrogen volume space velocity of 300h -1 , get component one;

[0071] c. Take 100 grams of MCM-41 molecular sieve and add it to 500 grams of deionized water, stirring thoroughly to form a suspension. Then add 20 grams of zirconium acetate and 50 milliliters of 35% ammonia water, continue heating at 80°C for 12 hours, then filter, wash with deionized water and dry at 120°C for 12 hours; then, take 12 grams of concentrated sulfuric acid, dissolve it in 100 milliliters of deionized water, impregnate the dried MCM-41, dry it at room temperature and pressure for 12 hours, dry it at 100-150°C for 12 hours, and calcine it at 500°C for 6 hours to obtain component two;

[0072] d. Take 30 g of component one and 70 g of component two, knead and mix, and then mechanically stamp to form a flaky granular catalyst, referred to as catalyst B. The composition of catalyst B is 23.1 wt% of an acidic silica-alumina complex; 61.7 wt% of an MCM-41 molecular sieve; 8.3 wt% of a solid superacid; and 6.9 wt% of a hydrogenation metal component.

[0073] Catalyst B was subjected to low-temperature nitrogen physical adsorption analysis and pyridine infrared acidity characterization. The results are shown in Table 1 and Figure 1 .

[0074] Catalyst B was subjected to hydroalkylation reaction evaluation, and the reaction results are shown in Table 1.

[0075] Example 3

[0076] a. Take 60 grams of silica, add it to 500 grams of deionized water, stir thoroughly to form a suspension; then add 125 grams of aluminum nitrate nonahydrate and stir at 60°C for 10 minutes. Subsequently, add 280 grams of urea and continue heating at 80°C for 12 hours; filter, wash with deionized water, dry at 120°C for 12 hours, and calcine at 600°C for 5 hours; then, exchange the calcined sample with 2M ammonium chloride solution at 90°C for 12 hours, wash with deionized water, dry at 120°C for 12 hours, and calcine at 550°C for 6 hours; obtain an acidic silica-alumina composite with a molar ratio of aluminum oxide to silica of 1:3;

[0077] b. Take 50 g of the above silica - alumina composite, loaded with 5 g of Ru, and impregnated with an equal volume of ruthenium chloride salt, dried at 120 ° C for 12 hours, and calcined at 550 ° C for 5 hours; the resulting sample was reduced at 300 ° C for 3 hours, with a hydrogen volume space velocity of 300h -1 , get component one;

[0078] c. Take 100 g of MCM-41 molecular sieve, added to 500 g of deionized water, stirred thoroughly to form a suspension; then added 12 g of titanium tetrachloride, added 80 ml of 35% ammonia, continued heating at 80 ℃ for 12 hours, then filtered, washed with deionized water and dried at 120 ℃ for 12 hours; then, take 6 g of concentrated sulfuric acid, dissolved in 100 ml of deionized water, impregnated in the dried MCM-41, dried at room temperature and pressure for 12 hours, dried at 100-150 ℃ for 12 hours, calcined at 500 ℃ for 6 hours to obtain component II;

[0079] d. Take 30 g of component one and 70 g of component two, knead and mix, and then mechanically stamp to form a flaky granular catalyst, referred to as catalyst C. The composition of catalyst C is 27.3 wt% of an acidic silica-alumina complex; 63.0 wt% of an MCM-41 molecular sieve; 7.0 wt% of a solid superacid; and 2.7 wt% of a hydrogenation metal component.

[0080] Catalyst C was subjected to low-temperature nitrogen physical adsorption analysis and pyridine infrared acidity characterization. The results are shown in Table 1 and Figure 1 .

[0081] Catalyst C was subjected to hydroalkylation reaction evaluation, and the reaction results are shown in Table 1.

[0082] Example 4

[0083] a. Take 100 g of 40 wt% silica sol, add 108 g of aluminum chloride hexahydrate with sufficient stirring, then adjust the pH to neutral with ammonia, and continue stirring for 12 hours; filter, wash with deionized water and dry at 120 ° C for 12 hours, calcined at 600 ° C for 5 hours; then, the calcined sample was exchanged with 2M ammonium chloride solution at 90 ° C for 12 hours, washed with deionized water, dried at 120 ° C for 12 hours, and calcined at 550 ° C for 6 hours; to obtain an acidic silica-alumina composite with a ratio of aluminum oxide to silicon oxide of 1:3;

[0084] b. Take 50 g of the above silica - alumina composite, loaded with 15 g of Ni, and impregnated with an equal volume of nickel nitrate, dried at 120 ° C for 12 hours, and calcined at 550 ° C for 5 hours; the resulting sample was reduced at 450 ° C for 3 hours and a hydrogen volume space velocity of 300h -1 , get component one;

[0085] c. Take 100 grams of MCM-41 molecular sieve and add it to 500 grams of deionized water. Stir thoroughly to form a suspension. Then add 10 grams of titanium tetrachloride and 80 milliliters of 35% ammonia water. Continue heating at 80°C for 12 hours. Then filter, wash with deionized water, and dry at 120°C for 12 hours. Then, take 6 grams of concentrated sulfuric acid, dissolve it in 100 milliliters of deionized water, and impregnate the dried MCM-41. Dry it at room temperature and pressure for 12 hours, dry it at 100-150°C for 12 hours, and calcine it at 500°C for 6 hours to obtain component two.

[0086] d. Take 35 g of component one and 65 g of component two, knead and mix, and then mechanically stamp to form a flaky granular catalyst, referred to as catalyst D. The composition of catalyst D is 26.9 wt% of an acidic silica-alumina complex; 57.1 wt% of an MCM-41 molecular sieve; 7.9 wt% of a solid superacid; and 8.1 wt% of a hydrogenation metal component.

[0087] Catalyst D was subjected to low-temperature nitrogen physical adsorption analysis and pyridine infrared acidity characterization, and the results obtained are shown in Tables 1 and Figure 1 .

[0088] Catalyst D was subjected to hydroalkylation reaction evaluation, and the reaction results are shown in Table 1.

[0089] Example 5

[0090] a. Take 60 grams of silica and add it to 500 grams of deionized water, stirring thoroughly to form a suspension. Then add 125 grams of aluminum nitrate nonahydrate and stir at 60°C for 10 minutes; then add 280 grams of urea and continue heating at 80°C for 12 hours; filter, wash with deionized water, dry at 120°C for 12 hours, and calcine at 600°C for 5 hours; then, exchange the calcined sample with 2M ammonium chloride solution at 90°C for 12 hours, wash with deionized water, dry at 120°C for 12 hours, and calcine at 550°C for 6 hours; obtain an acidic silica-alumina composite with a molar ratio of aluminum oxide to silica of 1:3;

[0091] b. Take 50 g of the above silica - alumina composite, loaded with 20 g of Ni, and impregnated with an equal volume of nickel nitrate, dried at 120 ° C for 12 hours, and calcined at 550 ° C for 5 hours; the resulting sample was reduced at 300 ° C for 3 hours, with a hydrogen volume space velocity of 300h -1 , get component one;

[0092] c. Take 100 grams of MCM-41 molecular sieve and add it to 500 grams of deionized water, stirring thoroughly to form a suspension. Then add 18 grams of zirconium acetate and 50 milliliters of 35% ammonia water, continue heating at 80°C for 12 hours, then filter, wash with deionized water and dry at 120°C for 12 hours; then, take 12 grams of concentrated sulfuric acid, dissolve it in 100 milliliters of deionized water, impregnate the dried MCM-41, dry it at room temperature and pressure for 12 hours, dry it at 100-150°C for 12 hours, and calcine it at 500°C for 6 hours to obtain component two;

[0093] d. Take 30 g of component one and 70 g of component two, kneaded and mixed, and then mechanically stamped to form a flaky granular catalyst, referred to as catalyst E. The composition of catalyst E is 21.4 wt% of an acidic silica - alumina complex; 62.5 wt% of an MCM-41 molecular sieve; 7.6 wt% of a solid superacid; and 8.6 wt% of a hydrogenation metal component.

[0094] Catalyst E was subjected to low-temperature nitrogen physical adsorption analysis and pyridine infrared acidity characterization. The results are shown in Tables 1 and Figure 1 .

[0095] Catalyst E was subjected to hydroalkylation reaction evaluation, and the reaction results are shown in Table 1.

[0096] Example 6

[0097] a. Take 60 grams of silica, add it to 500 grams of deionized water, and stir thoroughly to form a suspension. Then add 125 grams of aluminum nitrate nonahydrate and stir at 60°C for 10 minutes; then add 280 grams of urea and continue heating at 80°C for 12 hours; filter, wash with deionized water, dry at 120°C for 12 hours, and calcine at 600°C for 5 hours; then, exchange the calcined sample with 2M ammonium chloride solution at 90°C for 12 hours, wash with deionized water, dry at 120°C for 12 hours, and calcine at 550°C for 6 hours. An acidic silica-alumina composite with a molar ratio of aluminum oxide to silica of 1:3 is obtained;

[0098] b. Take 50 g of silica-alumina composite, loaded with 2 g of Ru, and impregnated with ruthenium trichloride salt in equal volumes, dried at 120 ° C for 12 hours, and calcined at 550 ° C for 5 hours; the resulting sample was reduced at 300 ° C for 3 hours and a hydrogen volume space velocity of 300h -1 , get component one;

[0099] c. Take 100 grams of MCM-41 molecular sieve and add it to 500 grams of deionized water, stirring thoroughly to form a suspension; then add 10 grams of zirconium acetate and 50 milliliters of 35% ammonia water, continue heating at 80°C for 12 hours, then filter, wash with deionized water and dry at 120°C for 12 hours. Subsequently, take 12 grams of concentrated sulfuric acid, dissolve it in 100 milliliters of deionized water, impregnate the dried MCM-41, dry it at room temperature and pressure for 12 hours, dry it at 100-150°C for 12 hours, and calcine it at 500°C for 6 hours to obtain component two;

[0100] d. Take 30 g of component one and 70 g of component two, kneaded and mixed, and then mechanically stamped to form a flaky granular catalyst, referred to as catalyst F. The composition of catalyst F is 28.9 wt% of an acidic silica-alumina complex; 65.6 wt% of an MCM-41 molecular sieve; 4.4 wt% of a solid superacid; and 1.1 wt% of a hydrogenation metal component.

[0101] Catalyst F was subjected to low-temperature nitrogen physical adsorption analysis and pyridine infrared acidity characterization. The results are shown in Table 1 and Figure 1 .

[0102] The prepared catalyst was designated as catalyst F. Catalyst F was subjected to a hydroalkylation reaction evaluation, and the reaction results are shown in Table 1.

[0103] from Figure 1 , It can be seen from the pore size distribution diagram of the catalysts prepared in Examples 1-6 that the average pore size distribution of the catalysts prepared in Examples 1-6 is above 5 nanometers, indicating that each catalyst has a mesoporous structure.

[0104] Example 7

[0105] Compared to Example 1, the catalyst composition is 30 wt% of an acidic silica-alumina composite; 53 wt% of an MCM-41 molecular sieve; 5 wt% of a solid superacid; and 12 wt% of a hydrogenation metal component. Catalyst G, designated as catalyst G, was subjected to low-temperature nitrogen physical adsorption analysis and pyridine infrared spectroscopy. The results are shown in Table 1.

[0106] Catalyst G was subjected to hydroalkylation reaction evaluation, and the reaction results are shown in Table 1.

[0107] Comparative Example 1

[0108] Compared with Example 1, the difference is that in step c, microporous ZSM-5 molecular sieve is used instead of MCM-41, and the other conditions are the same as those in Example 1.

[0109] The prepared catalyst was recorded as catalyst H. Catalyst H was subjected to low-temperature nitrogen physical adsorption analysis and pyridine infrared acidity characterization. The results are shown in Table 1.

[0110] Catalyst H was subjected to hydroalkylation reaction evaluation, and the reaction results are shown in Table 1.

[0111] Comparative Example 2

[0112] Compared with Example 1, the difference is that step a is not performed, and in step b, alumina is used instead of the acidic silica-alumina composite prepared in step a of Example 1. The other conditions are the same as those of Example 1.

[0113] The prepared catalyst is designated as Catalyst I. Catalyst I was subjected to low-temperature nitrogen physical adsorption analysis and pyridine infrared acidity characterization. The results are shown in Table 1.

[0114] Catalyst I was subjected to hydroalkylation reaction evaluation, and the reaction results are shown in Table 1.

[0115] Table 1 Catalyst pore size and its hydroalkylation reaction results

[0116]

[0117] As can be seen from Table 1, by adopting the method for preparing dicyclohexylbenzene of the present invention, the yield of dicyclohexylbenzene reaches more than 10% after the reaction.

[0118] Example 8

[0119] Using catalyst A prepared in Example 1, the hydroalkylation reaction conditions were:

[0120] Prepare a mixture of benzene and cyclohexylbenzene with a mass ratio of 1:8, and the total mass space velocity of benzene and cyclohexylbenzene is 2.0h -1, the molar ratio of benzene to hydrogen feed is 5; the reaction temperature is 120°C, and the reaction pressure is 0.6 MPa.

[0121] The benzene conversion rate was 38.6%, and the dicyclohexylbenzene yield was 10.3%.

[0122] Example 9

[0123] Using catalyst A prepared in Example 1, the hydroalkylation reaction conditions were:

[0124] Prepare a mixture of benzene and cyclohexylbenzene with a mass ratio of 1:8, and the total mass space velocity of benzene and cyclohexylbenzene is 2.5h -1 , the molar ratio of benzene to hydrogen feed is 6; the reaction temperature is 230°C, and the reaction pressure is 2.0 MPa.

[0125] The benzene conversion rate was 41.5%, and the dicyclohexylbenzene yield was 17.8%.

[0126] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A mesoporous bifunctional catalyst, characterized in that: The mesoporous bifunctional catalyst has an average pore diameter of more than 5 nanometers and a number of strong acid centers of more than 100 μmol / g. The mesoporous bifunctional catalyst contains: 10-30% by weight of an acidic silica-alumina composite; 50-70% by weight of an MCM-41 molecular sieve; 5-10% by weight of a solid superacid; and 1-15% by weight of a hydrogenation metal component.

2. The catalyst according to claim 1, wherein The average pore size of the mesoporous bifunctional catalyst is 5-10 nanometers; and / or The number of strong acid sites is 100-300 μmol / g; and / or The mesoporous bifunctional catalyst contains: 20-28 weight percent of an acidic silicon oxide-aluminum oxide composite; 55-65 weight percent of an MCM-41 molecular sieve; 6-9 weight percent of a solid superacid; and 2-11 weight percent of a hydrogenation metal component.

3. The catalyst according to claim 1 or 2, wherein The molar ratio of aluminum oxide to silicon oxide in the acidic silicon oxide-aluminum oxide composite is 1:1 to 1:

5.

4. The catalyst according to claim 1 or 2, wherein The solid superacid is selected from one or more of zirconium solid acid, titanium solid acid and iron solid acid; and / or The hydrogenation metal component element is selected from at least one of Ru, Ni, Co, Mo and W.

5. The catalyst according to claim 4, wherein The solid superacid is selected from zirconium solid acids; and / or The hydrogenation metal component element is selected from at least one of Ru and Ni.

6. The method for preparing the catalyst according to any one of claims 1 to 5, characterized in that: The method includes: a. Preparation of acidic silica - alumina composite; b The hydrogenation metal component is supported on the acidic silica - alumina composite to obtain a component; c The solid super acid is loaded on MCM-41 molecular sieve to obtain component two; d. Mix and knead component 1 and component 2 and shape them.

7. The preparation method according to claim 6, wherein Step a comprises: adding a silicon source and an aluminum source to water in proportion to form a mixed solution, mixing the mixed solution with a nitrogen-containing compound to react, drying, performing a first calcination, performing ammonium exchange, and then drying and performing a second calcination to obtain an acidic silicon oxide-aluminum oxide composite; Step b comprises: loading the hydrogenation metal component onto the acidic silica-alumina composite in the form of a salt solution, and then drying, third calcining, and reducing to obtain component 1; Step c comprises: loading the soluble salt of the solid superacid on the MCM-41 molecular sieve under alkaline conditions, drying, contacting with a sulfuric acid aqueous solution, and then drying and calcining for the fourth time to obtain component 2; Step d comprises: kneading component one and component two, and forming them.

8. The preparation method according to claim 7, wherein In step a, the silicon source is calculated as silicon dioxide, the aluminum source is calculated as aluminum oxide, and the mass ratio of the silicon source, the aluminum source, the nitrogen-containing compound and water is 1:0.5-3:2-8:5-20; and / or The reaction conditions of step a include: temperature of 0-100°C, time of 5-24 hours, The nitrogen-containing compound is selected from urea and / or ammonia; and / or The first calcination conditions include: calcination at 550-950° C. for 3-8 hours; and / or Ammonium exchange conditions include: exchanging with an ammonium salt solution at 40-100°C for 1-24 hours; and / or The second calcination conditions include: calcination at 450-650°C for 3-8 hours; and / or In step b, The third calcination condition includes: calcination at 450-650°C for 3-8 hours; and / or The reduction conditions include: reduction under hydrogen atmosphere, reduction temperature of 100-500 ° C, reduction time of 0.5-12 hours, hydrogen volume space velocity of 100-600 h -1 and / or In step c, The fourth calcination condition includes: calcination at 450-650° C. for 3-8 hours.

9. Use of the mesoporous bifunctional catalyst according to any one of claims 1 to 5 in the preparation of dicyclohexylbenzene.

10. A method for preparing dicyclohexylbenzene, characterized in that: The method comprises: carrying out contact reaction between benzene and cyclohexylbenzene in the presence of a mesoporous bifunctional catalyst; the mesoporous bifunctional catalyst is the mesoporous bifunctional catalyst described in any one of claims 1-5.

11. The preparation method according to claim 10, wherein The weight ratio of benzene to cyclohexylbenzene is 1:5 to 1:10; and / or The conditions of the contact reaction include: reaction temperature of 120-230° C., reaction pressure of 0.6-2.0 MPa; and / or The molar ratio of benzene to hydrogen is 2 to 6; The total mass space velocity of benzene and cyclohexylbenzene is 1.6~3.0 h -1 .

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