Catalyst for synthesizing cyclohexylbenzene based on surface modification as well as preparation method and application of catalyst

Abstract

The invention provides a catalyst for synthesizing cyclohexylbenzene based on surface modification and a preparation method and application thereof, the catalyst for synthesizing cyclohexylbenzene comprises a carrier, and a first active component and a second active component which are loaded on the surface of the carrier, and the second active component partially covers the surface of the first active component; wherein the carrier comprises a molecular sieve; the first active component comprises Pt and / or Pd, and the second active component comprises Ni and / or Ru. The carrier is subjected to surface modification by adopting a specific type of metal, so that the performance of the catalyst is effectively regulated and controlled, the selectivity of a by-product cyclohexane is reduced, the yield of a target product cyclohexylbenzene is improved, and large-scale popularization and application are facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of catalyst preparation, and relates to a cyclohexylbenzene synthesis catalyst, in particular to a cyclohexylbenzene synthesis catalyst based on surface modification, and a preparation method and application thereof. Background Art

[0002] Cyclohexylbenzene (CHB) is an important intermediate, widely used in liquid crystals, plastics, coatings, adhesives and other fields. Cyclohexylbenzene liquid crystals have extremely high chemical and photochemical stability, low viscosity and excellent physical properties, and are one of the ideal materials for display devices. As an additive to lithium-ion battery electrolytes, cyclohexylbenzene has anti-overcharge properties and can improve the safety performance of batteries. In addition, phenol and cyclohexanone can be prepared through the peroxidation and decomposition reactions of cyclohexylbenzene, which are used in the production of bulk chemical raw materials such as phenolic resins, caprolactam and nylon, and have good application prospects.

[0003] The research on preparing cyclohexylbenzene by hydroalkylation of benzene began in the 1970s and 1980s. The catalyst developed in the early stage has the problem of low selectivity of cyclohexylbenzene. For example, ExxonMobil has developed a catalyst loaded with hydrogenation metal based on MCM-22 series molecular sieves (US2011 / 0015457A1, US2011 / 0021841A1), which is used for preparing cyclohexylbenzene by hydroalkylation of benzene. This technology has high selectivity for by-product cyclohexane. Patents US4094918, US4219689 and US4329531 of Phillips Petroleum Company of the United States use zeolite catalysts treated with Ni-rare earth and use Pd as an auxiliary agent, and the conversion rate of benzene and the yield of CHB are relatively low. The above-mentioned method has the problem of high selectivity of by-product cyclohexane and low yield of product cyclohexylbenzene in the process of preparing cyclohexylbenzene.

[0004] Therefore, how to provide a catalyst for cyclohexylbenzene synthesis, reduce the selectivity of by-product cyclohexane, and improve the yield of target product cyclohexylbenzene has become an urgent problem to be solved by those skilled in the art. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a catalyst for cyclohexylbenzene synthesis based on surface modification, and a preparation method and application thereof, wherein the surface of the carrier is modified by a specific type of metal, the catalyst performance is effectively regulated, the selectivity of the by-product cyclohexane is reduced, and the yield of the target product cyclohexylbenzene is increased, which is conducive to large-scale promotion and application.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a surface-modified cyclohexylbenzene synthesis catalyst, wherein the cyclohexylbenzene synthesis catalyst comprises a carrier and a first active component and a second active component loaded on the surface of the carrier, and the second active component partially covers the surface of the first active component.

[0008] Wherein, the carrier includes a molecular sieve; the first active component includes Pt and / or Pd, and the second active component includes Ni and / or Ru.

[0009] The present invention loads two specific types of metal active components on the surface of the carrier and limits the second active component to partially cover the surface of the first active component, thereby achieving the surface modification effect of the second active component on the first active component, effectively regulating the catalyst performance, reducing the selectivity of the by-product cyclohexane, and improving the yield of the target product cyclohexylbenzene, which is conducive to large-scale promotion and application.

[0010] Preferably, the molecular sieve includes any one of type 3A molecular sieve, type 4A molecular sieve, MFI molecular sieve or MWW molecular sieve, or a combination of at least two of them.

[0011] Preferably, the silicon to aluminum molar ratio of the molecular sieve is (5-25):1.

[0012] Preferably, the specific surface area of ​​the molecular sieve is 200-800m 2 / g.

[0013] Preferably, based on the mass of the carrier as a calculation basis, the loading amount of the first active component is 0.1-0.35 wt %.

[0014] Preferably, based on the mass of the carrier as a calculation basis, the loading amount of the second active component is 0.3-1.5 wt %.

[0015] Preferably, the second active component covers an area of ​​20%-80% of the surface area of ​​the first active component.

[0016] In a second aspect, the present invention provides a method for preparing the catalyst for cyclohexylbenzene synthesis as described in the first aspect, the preparation method comprising sequentially performing carrier preparation, a first load and a second load.

[0017] The first load is used to load a first active component onto the surface of the carrier, and the second load is used to load a second active component onto the surface of the carrier.

[0018] Preferably, the carrier is prepared by a hydrothermal synthesis method.

[0019] Preferably, the first load and the second load are respectively applied by an impregnation method.

[0020] Preferably, the impregnation solution used for the first loading comprises a platinum salt solution and / or a palladium salt solution.

[0021] The solute in the platinum salt solution includes any one of chloroplatinic acid, potassium tetrachloroplatinate or potassium hexachloroplatinate, or a combination of at least two of them, and chloroplatinic acid is more preferred.

[0022] Preferably, the solute in the palladium salt solution includes any one of palladium chloride, chloropalladic acid, tetraaminopalladium nitrate or sodium tetrachloropalladate, or a combination of at least two thereof, and more preferably chloropalladic acid.

[0023] Preferably, the first load is dried and calcined in sequence after impregnation, and the calcination is carried out in an atmosphere of reducing gas, the calcination temperature is 50-400° C., and the calcination time is 1-8 hours.

[0024] Preferably, the impregnation solution used for the second loading comprises a nickel salt solution and / or a ruthenium salt solution.

[0025] The solute in the nickel salt solution includes any one of nickel chloride, nickel sulfate, nickel nitrite or nickel hydroxide, or a combination of at least two of them, and nickel chloride is more preferred.

[0026] Preferably, the solute in the ruthenium salt solution includes hydrated ruthenium trichloride and / or ruthenium nitrate, and more preferably hydrated ruthenium trichloride.

[0027] Preferably, the impregnation solution used for the second loading is also mixed with polyvinyl pyrrolidone (PVP) and / or ascorbic acid (AA).

[0028] Preferably, the second load is dried after impregnation, and the drying temperature is 25-150° C. and the drying time is 8-48 hours.

[0029] In a third aspect, the present invention provides a method for synthesizing cyclohexylbenzene by hydroalkylation of benzene, wherein the method uses the catalyst for cyclohexylbenzene synthesis as described in the first aspect to carry out a benzene hydroalkylation reaction.

[0030] Preferably, the liquid phase mass space velocity (WHSV) of the benzene hydroalkylation reaction is 2-6h -1 .

[0031] Preferably, the molar ratio of hydrogen to benzene in the benzene hydroalkylation reaction is (1-2):1.

[0032] Preferably, the temperature of the benzene hydroalkylation reaction is 150-200°C.

[0033] Preferably, the pressure of the benzene hydroalkylation reaction is 1-3 MPa.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present invention loads two specific types of metal active components on the surface of the carrier and limits the second active component to partially cover the surface of the first active component, thereby achieving the surface modification effect of the second active component on the first active component, effectively regulating the catalyst performance, reducing the selectivity of the by-product cyclohexane, and improving the yield of the target product cyclohexylbenzene, which is conducive to large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the element distribution mapping diagram of the cyclohexylbenzene synthesis catalyst obtained in Example 1. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0038] A certain embodiment of the present invention provides a surface-modified cyclohexylbenzene synthesis catalyst, which includes a carrier and a first active component and a second active component loaded on the surface of the carrier, and the second active component partially covers the surface of the first active component.

[0039] Wherein, the carrier includes a molecular sieve; the first active component includes Pt and / or Pd, and the second active component includes Ni and / or Ru.

[0040] The present invention loads two specific types of metal active components on the surface of the carrier and limits the second active component to partially cover the surface of the first active component, thereby achieving the surface modification effect of the second active component on the first active component, effectively regulating the catalyst performance, reducing the selectivity of the by-product cyclohexane, and improving the yield of the target product cyclohexylbenzene, which is conducive to large-scale promotion and application.

[0041] In certain embodiments, the molecular sieve includes any one of type 3A molecular sieve, type 4A molecular sieve, MFI type molecular sieve or MWW type molecular sieve, or a combination of at least two of them. Typical but non-limiting combinations include a combination of type 3A molecular sieve and type 4A molecular sieve, a combination of type 4A molecular sieve and MFI type molecular sieve, or a combination of MFI type molecular sieve and MWW type molecular sieve.

[0042] In certain embodiments, the silicon to aluminum molar ratio of the molecular sieve is (5-25):1, for example, 5:1, 10:1, 15:1, 20:1 or 25:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0043] In certain embodiments, the molecular sieve has a specific surface area of ​​200-800 m 2 / g, for example, it can be 200m 2 / g, 250m 2 / g、300m 2 / g, 350m 2 / g, 400m 2 / g, 450m 2 / g、500m 2 / g, 550m 2 / g, 600m 2 / g, 650m 2 / g、700m 2 / g, 750m 2 / g or 800m 2 / g, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0044] In certain embodiments, based on the mass of the carrier as the calculation basis, the loading amount of the first active component is 0.1-0.35wt%, for example, it can be 0.1wt%, 0.15wt%, 0.2wt%, 0.25wt%, 0.3wt% or 0.35wt%, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] In certain embodiments, based on the mass of the carrier, the loading amount of the second active component is 0.3-1.5wt%, for example, it can be 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt% or 1.5wt%, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] In certain embodiments, the surface area covered by the second active component on the surface of the first active component accounts for 20%-80%, for example, it can be 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0047] The present invention also provides a method for preparing the catalyst for cyclohexylbenzene synthesis described in any embodiment, wherein the method comprises sequentially performing carrier preparation, first loading and second loading.

[0048] The first load is used to load a first active component onto the surface of the carrier, and the second load is used to load a second active component onto the surface of the carrier.

[0049] In certain embodiments, the carrier is prepared by a hydrothermal synthesis method.

[0050] In some embodiments, the hydrothermal synthesis method specifically comprises the following steps:

[0051] (1) Dissolve 1-500g of alkali in 100-50000g of deionized water, then add 100-1000g of NaAlO2 and stir to dissolve, then add 500-3000g of hexamethylene amine and stir for 1-100min; then add 50-3000g of boric acid and stir for 2-120min, and keep warm in a water bath at 30-100°C for 1-8h. The alkali in this step is any one of NaOH, KOH or Ca(OH)2 or a combination of at least two of them, preferably NaOH.

[0052] (2) 1-10000 g of colloidal silica (Ludox AS-30) is heated to 70° C. in a water bath and slowly dripped into the solution obtained in step (1) under vigorous stirring to form a gel product. The container containing Ludox AS-40 is rinsed with 500 g of water several times and transferred to the sol system.

[0053] (3) The obtained gel is stirred for 1-60 minutes, transferred to a reaction vessel, and the temperature is controlled at 60° C. After stirring for 30-180 minutes, the temperature is raised to 120-240° C. and crystallization is continued for 3-20 days.

[0054] (4) After washing the product, it is dried at 120° C. for 12-60 hours and the carrier is collected.

[0055] In some embodiments, the first loading and the second loading are respectively carried out by dipping.

[0056] In certain embodiments, the impregnation solution used for the first loading comprises a platinum salt solution and / or a palladium salt solution.

[0057] In certain embodiments, the solute in the platinum salt solution includes any one of chloroplatinic acid, potassium tetrachloroplatinate or potassium hexachloroplatinate, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of chloroplatinic acid and potassium tetrachloroplatinate, a combination of potassium tetrachloroplatinate and potassium hexachloroplatinate, a combination of chloroplatinic acid and potassium hexachloroplatinate, or a combination of chloroplatinic acid, potassium tetrachloroplatinate and potassium hexachloroplatinate, and chloroplatinic acid is further preferred.

[0058] In certain embodiments, the solute in the palladium salt solution includes any one of palladium chloride, chloropalladic acid, tetraaminopalladium nitrate or sodium tetrachloropalladate, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of palladium chloride and chloropalladic acid, a combination of chloropalladic acid and tetraaminopalladium nitrate, a combination of tetraaminopalladium nitrate and sodium tetrachloropalladate, a combination of palladium chloride, chloropalladic acid and tetraaminopalladium nitrate, or a combination of chloropalladic acid, tetraaminopalladium nitrate and sodium tetrachloropalladate, and chloropalladic acid is further preferred.

[0059] In certain embodiments, the first load is dried and calcined in sequence after impregnation, and the calcination is carried out in an atmosphere of reducing gas, the calcination temperature is 50-400°C, for example, it can be 50°C, 100°C, 150°C, 200°C, 250°C, 300°C, 350°C or 400°C, and the calcination time is 1-8h, for example, it can be 1h, 2h, 3h, 4h, 5h, 6h, 7h or 8h, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0060] In some embodiments, the first load specifically includes the following steps:

[0061] (1) Disperse 0.1-1 g of a precursor of a first active component in 500 mL of deionized water, wherein the precursor of the first active component includes a platinum salt and / or a palladium salt.

[0062] (2) Add 100 g of the carrier to the dispersion obtained in step (1) for impregnation, continue stirring for 1-10 hours, and then centrifuge to obtain a wet powder, wash it three times with water, and then dry it at 25-150° C. for 8-48 hours to obtain an unreduced catalyst powder.

[0063] (3) The catalyst powder obtained in step (2) is calcined in a hydrogen atmosphere at 50-400° C. for 1-8 h to obtain a single-component catalyst loaded with the first active component.

[0064] In certain embodiments, the impregnation solution used for the second loading includes a nickel salt solution and / or a ruthenium salt solution.

[0065] In certain embodiments, the solute in the nickel salt solution includes any one of nickel chloride, nickel sulfate, nickel nitrite or nickel hydroxide, or a combination of at least two of them. Typical but non-limiting combinations include a combination of nickel chloride and nickel sulfate, a combination of nickel sulfate and nickel nitrite, a combination of nickel nitrite and nickel hydroxide, a combination of nickel chloride, nickel sulfate and nickel nitrite, or a combination of nickel sulfate, nickel nitrite and nickel hydroxide, and nickel chloride is further preferred.

[0066] In certain embodiments, the solute in the ruthenium salt solution includes hydrated ruthenium trichloride and / or ruthenium nitrate, and more preferably hydrated ruthenium trichloride.

[0067] In certain embodiments, the impregnation solution used for the second loading further contains polyvinyl pyrrolidone and / or ascorbic acid.

[0068] In certain embodiments, the second load is dried after impregnation, and the drying temperature is 25-150°C, for example, 25°C, 50°C, 75°C, 100°C, 125°C or 150°C, and the drying time is 8-48h, for example, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h, 26h, 28h, 30h, 32h, 34h, 36h, 38h, 40h, 42h, 44h, 46h or 48h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0069] In some embodiments, the second load specifically includes the following steps:

[0070] (1) 50 g of a single-component catalyst loaded with a first active component is dispersed in 500 mL of deionized water, and 0.1-1 g of a precursor of a second active component is added, wherein the precursor of the second active component includes a nickel salt and / or a ruthenium salt.

[0071] (2) Add 5-50 g of PVP to the slurry obtained in step (1) and stir for 10-120 min, wherein the molecular weight of the PVP is any one of 8000, 24000, 58000, and 1300000, preferably 24000; then add 20-200 mL of AA solution with a concentration of 0.1-0.6 mol / L, continue mixing for 1-6 h, and then centrifuge to obtain a wet powder, wash three times with water, and then dry at 25-150° C. for 8-48 h to obtain a dual-component catalyst simultaneously loaded with the first active component and the second active component, i.e., a catalyst for cyclohexylbenzene synthesis.

[0072] The present invention also provides a method for synthesizing cyclohexylbenzene by hydrogenation alkylation of benzene. The method uses the catalyst for synthesizing cyclohexylbenzene described in any embodiment to carry out a benzene hydrogenation alkylation reaction.

[0073] In certain embodiments, the liquid phase mass space velocity of the benzene hydroalkylation reaction is 2-6h -1 , for example, it can be 2h -1 , 2.5h -1 , 3h -1 , 3.5h -1 , 4h -1 , 4.5h -1 , 5h -1 , 5.5h -1 or 6h -1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0074] In certain embodiments, the molar ratio of hydrogen to benzene in the benzene hydroalkylation reaction is (1-2):1, for example, 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1 or 2:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0075] In certain embodiments, the temperature of the benzene hydroalkylation reaction is 150-200°C, for example, 150°C, 160°C, 170°C, 180°C, 190°C or 200°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0076] In certain embodiments, the pressure of the benzene hydroalkylation reaction is 1-3 MPa, for example, 1 MPa, 1.2 MPa, 1.4 MPa, 1.6 MPa, 1.8 MPa, 2 MPa, 2.2 MPa, 2.4 MPa, 2.6 MPa, 2.8 MPa or 3 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0077] In certain embodiments, the method for synthesizing cyclohexylbenzene by hydrogenation alkylation of benzene specifically comprises: loading 20 g of catalyst into a fixed bed, with a loading height-to-diameter ratio of L / d=36.3; activating the catalyst by heating from 18°C ​​to 180°C at a rate of 1°C / min for 5 hours under a hydrogen flow rate of 200 mL / min, and starting to feed benzene at 80 g / h after the catalyst activation is completed, controlling the hydrogen-to-benzene molar ratio to be (1-2):1, and WHSV=2-6h. -1 , the reaction pressure is 1-3MPa, and the reaction temperature is 150-200℃.

[0078] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0079] Example 1

[0080] This embodiment provides a surface-modified cyclohexylbenzene synthesis catalyst and a preparation method thereof, the preparation method comprising the following steps:

[0081] (1) Preparation of carrier:

[0082] (1.1) Dissolve 100 g of NaOH in 6000 g of deionized water, add 480 g of NaAlO2 and stir to dissolve, then add 1460 g of hexamethylenediamine and stir for 10 min; then add 700 g of boric acid and stir for 10 min, and keep warm in a water bath at 70°C for 2 h.

[0083] (1.2) 5300 g of colloidal silica (Ludox AS-30) was heated to 70° C. in a water bath and slowly dripped into the solution obtained in step (1) under vigorous stirring to form a gel product. The container containing Ludox AS-40 was rinsed with 500 g of water several times and transferred to the sol system.

[0084] (1.3) The obtained gel was stirred for 20 min and transferred to a reactor. The temperature was controlled at 60 °C. After stirring for 40 min, the temperature was raised to 150 °C and crystallization was continued for 7 days.

[0085] (1.4) After washing the product, it was dried at 120°C for 16 h and the carrier was collected.

[0086] (2) First load:

[0087] (2.1) Disperse 0.6 g of sodium tetrachloropalladate in 500 mL of deionized water.

[0088] (2.2) Add 100 g of the carrier to the dispersion obtained in step (2.1) for impregnation, continue stirring for 3 hours, and then centrifuge to obtain a wet powder. Wash it three times with water, and then dry it at 50° C. for 12 hours to obtain an unreduced catalyst powder.

[0089] (2.3) The catalyst powder obtained in step (2.2) was calcined in a hydrogen atmosphere at 200° C. for 4 h to obtain a single-component catalyst loaded with Pd.

[0090] (3) Second load:

[0091] (3.1) Disperse 50 g of the Pd-loaded single-component catalyst in 500 mL of deionized water, and add 0.8 g of hydrated ruthenium trichloride.

[0092] (3.2) 20 g of PVP with a molecular weight of 8000 was added to the slurry obtained in step (3.1) and stirred for 60 min; then 40 mL of 0.2 mol / L AA solution was added, and the mixture was mixed for 2 h and then centrifuged to obtain a wet powder, which was washed three times with water and then dried at 75 ° C for 14 h to obtain a dual-component catalyst loaded with Pd and Ru, i.e., a catalyst for cyclohexylbenzene synthesis.

[0093] Figure 1 This is the element distribution mapping diagram of the cyclohexylbenzene synthesis catalyst obtained in this example.

[0094] Depend on Figure 1 It can be seen that the catalyst obtained in this embodiment includes an MFI-type ZSM-5 molecular sieve carrier with Si as the main component and a first active component Pd and a second active component Ru loaded on the surface of the carrier, and the second active component Ru partially covers the surface of the first active component Pd, with an area accounting for about 40%, indicating that the second active component Ru has a surface modification effect on the first active component Pd.

[0095] Example 2

[0096] This embodiment provides a surface-modified cyclohexylbenzene synthesis catalyst and a preparation method thereof, the preparation method comprising the following steps:

[0097] (1) Preparation of carrier:

[0098] (1.1) Dissolve 300 g of KOH in 8000 g of deionized water, add 600 g of NaAlO2 and stir to dissolve, then add 1400 g of hexamethylenediamine and stir for 80 min; then add 1500 g of boric acid and stir for 100 min, and keep warm in a water bath at 60°C for 5 h.

[0099] (1.2) 5000 g of colloidal silica (Ludox AS-30) was heated to 70° C. in a water bath and slowly dripped into the solution obtained in step (1) under vigorous stirring to form a gel product. The container containing Ludox AS-40 was rinsed with 500 g of water several times and transferred to the sol system.

[0100] (1.3) The obtained gel was stirred for another 40 min, transferred to a reactor, and the temperature was controlled at 60°C. After stirring for 80 min, the temperature was raised to 140°C and crystallization was continued for 10 days.

[0101] (1.4) After washing the product, it was dried at 120°C for 40 hours and the carrier was collected.

[0102] (2) First load:

[0103] (2.1) Disperse 0.4 g of tetraaminopalladium nitrate in 500 mL of deionized water.

[0104] (2.2) Add 100 g of the carrier to the dispersion obtained in step (2.1) for impregnation, continue stirring for 8 hours, and then centrifuge to obtain a wet powder. Wash it with water three times, and then dry it at 75°C for 10 hours to obtain an unreduced catalyst powder.

[0105] (2.3) The catalyst powder obtained in step (2.2) was calcined in a hydrogen atmosphere at 250° C. for 2 h to obtain a single-component catalyst loaded with Pd.

[0106] (3) Second load:

[0107] (3.1) Disperse 50 g of Pd-loaded single-component catalyst in 500 mL of deionized water and add 0.7 g of nickel chloride.

[0108] (3.2) 30 g of PVP with a molecular weight of 24,000 was added to the slurry obtained in step (3.1) and stirred for 10 min; then 60 mL of 0.3 mol / L AA solution was added, and the mixture was mixed for 3 h and then centrifuged to obtain a wet powder, which was washed three times with water and then dried at 110° C. for 14 h to obtain a dual-component catalyst loaded with Pd and Ni, i.e., a catalyst for cyclohexylbenzene synthesis.

[0109] The element distribution of the catalyst obtained in this example is similar to that in Example 1, so it will not be described here in detail.

[0110] Example 3

[0111] This embodiment provides a surface-modified cyclohexylbenzene synthesis catalyst and a preparation method thereof, the preparation method comprising the following steps:

[0112] (1) Preparation of carrier:

[0113] (1.1) Dissolve 320 g of Ca(OH)2 in 4000 g of deionized water, add 230 g of NaAlO2 and stir to dissolve, then add 1270 g of hexamethylenediamine and stir for 100 min; then add 2530 g of boric acid and stir for 52 min, and keep warm in a water bath at 60°C for 4 h.

[0114] (1.2) 5600 g of colloidal silica (Ludox AS-30) was heated to 70° C. in a water bath and slowly dripped into the solution obtained in step (1) under vigorous stirring to form a gel product. The container containing Ludox AS-40 was rinsed with 500 g of water several times and transferred to the sol system.

[0115] (1.3) The obtained gel was stirred for another 40 min, transferred to a reactor, and the temperature was controlled at 60°C. After stirring for 80 min, the temperature was raised to 190°C and crystallization was continued for 15 days.

[0116] (1.4) After washing the product, it was dried at 120°C for 20 h and the carrier was collected.

[0117] (2) First load:

[0118] (2.1) Disperse 0.45 g of potassium tetrachloroplatinate in 500 mL of deionized water.

[0119] (2.2) Add 100 g of the carrier to the dispersion obtained in step (2.1) for impregnation, continue stirring for 6 hours, and then centrifuge to obtain a wet powder. Wash it three times with water, and then dry it at 150° C. for 19 hours to obtain an unreduced catalyst powder.

[0120] (2.3) The catalyst powder obtained in step (2.2) was calcined at 300°C for 6 h in a hydrogen atmosphere to obtain a single-component catalyst loaded with Pt.

[0121] (3) Second load:

[0122] (3.1) Disperse 50 g of Pt-loaded single-component catalyst in 500 mL of deionized water and add 1 g of hydrated ruthenium trichloride.

[0123] (3.2) 35 g of PVP with a molecular weight of 24,000 was added to the slurry obtained in step (3.1) and stirred for 120 min; then 80 mL of 0.5 mol / L AA solution was added, and the mixture was mixed for 2 h and then centrifuged to obtain a wet powder, which was washed three times with water and then dried at 80° C. for 30 h to obtain a dual-component catalyst simultaneously loaded with Pt and Ru, i.e., a catalyst for cyclohexylbenzene synthesis.

[0124] The element distribution of the catalyst obtained in this example is similar to that in Example 1, so it will not be described here in detail.

[0125] Example 4

[0126] This embodiment provides a surface-modified cyclohexylbenzene synthesis catalyst and a preparation method thereof, the preparation method comprising the following steps:

[0127] (1) Preparation of carrier:

[0128] (1.1) Dissolve 270 g of NaOH in 10,000 g of deionized water, add 460 g of NaAlO2 and stir to dissolve, then add 1,600 g of hexamethylenediamine and stir for 50 min; then add 2,400 g of boric acid and stir for 120 min, and keep warm in a water bath at 60°C for 2 h.

[0129] (1.2) 7900 g of colloidal silica (Ludox AS-30) was heated to 70° C. in a water bath and slowly dripped into the solution obtained in step (1) under vigorous stirring to form a gel product. The container containing Ludox AS-40 was rinsed with 500 g of water several times and transferred to the sol system.

[0130] (1.3) The obtained gel was stirred for 60 min and transferred to a reactor. The temperature was controlled at 60 °C. After stirring for 120 min, the temperature was raised to 190 °C and crystallization was continued for 11 days.

[0131] (1.4) After washing the product, it was dried at 120°C for 40 hours and the carrier was collected.

[0132] (2) First load:

[0133] (2.1) Disperse 0.3 g of potassium tetrachloroplatinate in 500 mL of deionized water.

[0134] (2.2) Add 100 g of the carrier to the dispersion obtained in step (2.1) for impregnation, continue stirring for 6 hours, and then centrifuge to obtain a wet powder. Wash it three times with water, and then dry it at 150° C. for 18 hours to obtain an unreduced catalyst powder.

[0135] (2.3) The catalyst powder obtained in step (2.2) was calcined in a hydrogen atmosphere at 100° C. for 6 h to obtain a single-component catalyst loaded with Pt.

[0136] (3) Second load:

[0137] (3.1) Disperse 50 g of Pt-loaded single-component catalyst in 500 mL of deionized water and add 1 g of nickel chloride.

[0138] (3.2) 50 g of PVP with a molecular weight of 24,000 was added to the slurry obtained in step (3.1) and stirred for 120 min; then 200 mL of 0.6 mol / L AA solution was added, and the mixture was mixed for 5 h and then centrifuged to obtain a wet powder, which was washed three times with water and then dried at 75° C. for 32 h to obtain a dual-component catalyst simultaneously loaded with Pt and Ni, i.e., a catalyst for cyclohexylbenzene synthesis.

[0139] The element distribution of the catalyst obtained in this example is similar to that in Example 1, so it will not be described here in detail.

[0140] Example 5

[0141] This embodiment provides a surface-modified cyclohexylbenzene synthesis catalyst and a preparation method thereof. Except that the sodium tetrachloropalladate in step (2.1) is replaced with an equal mass of chloropalladic acid, the remaining steps and conditions are the same as those in Example 1, and thus are not described in detail here.

[0142] Example 6

[0143] This embodiment provides a surface-modified cyclohexylbenzene synthesis catalyst and a preparation method thereof. Except that the tetraaminopalladium nitrate in step (2.1) is replaced with an equal mass of palladium chloride, the remaining steps and conditions are the same as those in Example 2, and thus are not described in detail here.

[0144] Example 7

[0145] This embodiment provides a surface-modified cyclohexylbenzene synthesis catalyst and a preparation method thereof. Except that the potassium tetrachloroplatinate in step (2.1) is replaced with an equal mass of potassium hexachloroplatinate, the remaining steps and conditions are the same as those in Example 3, and thus are not described in detail here.

[0146] Example 8

[0147] This embodiment provides a surface-modified cyclohexylbenzene synthesis catalyst and a preparation method thereof. Except that the potassium tetrachloroplatinate in step (2.1) is replaced with an equal mass of chloroplatinic acid, the remaining steps and conditions are the same as those in Example 4, and thus are not described in detail here.

[0148] Example 9

[0149] This embodiment provides a surface-modified cyclohexylbenzene synthesis catalyst and a preparation method thereof. Except that the hydrated ruthenium trichloride in step (3.1) is replaced with an equal mass of ruthenium nitrate, the remaining steps and conditions are the same as those in Example 1, and therefore are not described in detail here.

[0150] Example 10

[0151] This embodiment provides a surface-modified cyclohexylbenzene synthesis catalyst and a preparation method thereof. Except that the nickel chloride in step (3.1) is replaced with an equal mass of nickel sulfate, the remaining steps and conditions are the same as those in Example 2, and therefore are not described in detail here.

[0152] Embodiment 11

[0153] This embodiment provides a surface-modified cyclohexylbenzene synthesis catalyst and a preparation method thereof. Except that the hydrated ruthenium trichloride in step (3.1) is replaced with an equal mass of nickel nitrite, the remaining steps and conditions are the same as those in Example 3, and therefore are not described in detail here.

[0154] Example 12

[0155] This embodiment provides a surface-modified cyclohexylbenzene synthesis catalyst and a preparation method thereof. Except that the nickel chloride in step (3.1) is replaced with an equal mass of nickel hydroxide, the remaining steps and conditions are the same as those in Example 4, and therefore are not described in detail here.

[0156] Example 13

[0157] This embodiment provides a surface-modified cyclohexylbenzene synthesis catalyst and a preparation method thereof. Except that PVP is not added in step (3.2), the remaining steps and conditions are the same as those in Example 1, and thus are not described in detail here.

[0158] Embodiment 14

[0159] This embodiment provides a surface-modified cyclohexylbenzene synthesis catalyst and a preparation method thereof. Except that the AA solution is not added in step (3.2), the remaining steps and conditions are the same as those in Example 1, and thus are not described in detail here.

[0160] Embodiment 15

[0161] This embodiment provides a surface-modified cyclohexylbenzene synthesis catalyst and a preparation method thereof. Except that PVP and AA solution are not added in step (3.2), the remaining steps and conditions are the same as those in Example 1, so they are not described here.

[0162] Example 16

[0163] This embodiment provides a surface-modified cyclohexylbenzene synthesis catalyst and a preparation method thereof. Except that the AA solution in step (3.2) is replaced by 40 mL of an ice-water solution containing 4 g of NaBH4, the remaining steps and conditions are the same as those in Example 1, and thus are not described in detail here.

[0164] Comparative Example 1

[0165] This comparative example provides a cyclohexylbenzene synthesis catalyst and a preparation method thereof, the preparation method comprising the following steps:

[0166] (1) Preparation of carrier:

[0167] (1.1) Dissolve 100 g of NaOH in 6000 g of deionized water, add 480 g of NaAlO2 and stir to dissolve, then add 1460 g of hexamethylenediamine and stir for 10 min; then add 700 g of boric acid and stir for 10 min, and keep warm in a water bath at 70°C for 2 h.

[0168] (1.2) 5300 g of colloidal silica (Ludox AS-30) was heated to 70° C. in a water bath and slowly dripped into the solution obtained in step (1) under vigorous stirring to form a gel product. The container containing Ludox AS-40 was rinsed with 500 g of water several times and transferred to the sol system.

[0169] (1.3) The obtained gel was stirred for 20 min and transferred to a reactor. The temperature was controlled at 60 °C. After stirring for 40 min, the temperature was raised to 150 °C and crystallization was continued for 7 days.

[0170] (1.4) After washing the product, it was dried at 120°C for 16 h and the carrier was collected.

[0171] (2) Active ingredient loading:

[0172] (2.1) Disperse 0.6 g of sodium tetrachloropalladate and 0.8 g of hydrated ruthenium trichloride in 500 mL of deionized water.

[0173] (2.2) Add 100 g of the carrier to the dispersion obtained in step (2.1) for impregnation, continue stirring for 3 hours, and then centrifuge to obtain a wet powder. Wash it three times with water, and then dry it at 50° C. for 12 hours to obtain an unreduced catalyst powder.

[0174] (2.3) The catalyst powder obtained in step (2.2) is calcined in a hydrogen atmosphere at 200° C. for 4 h to obtain a dual-component catalyst loaded with both Pd and Ru, i.e., a catalyst for cyclohexylbenzene synthesis.

[0175] Comparative Example 2

[0176] This comparative example provides a cyclohexylbenzene synthesis catalyst and a preparation method thereof, the preparation method comprising the following steps:

[0177] (1) Preparation of carrier:

[0178] (1.1) Dissolve 100 g of NaOH in 6000 g of deionized water, add 480 g of NaAlO2 and stir to dissolve, then add 1460 g of hexamethylenediamine and stir for 10 min; then add 700 g of boric acid and stir for 10 min, and keep warm in a water bath at 70°C for 2 h.

[0179] (1.2) 5300 g of colloidal silica (Ludox AS-30) was heated to 70° C. in a water bath and slowly dripped into the solution obtained in step (1) under vigorous stirring to form a gel product. The container containing Ludox AS-40 was rinsed with 500 g of water several times and transferred to the sol system.

[0180] (1.3) The obtained gel was stirred for 20 min and transferred to a reactor. The temperature was controlled at 60 °C. After stirring for 40 min, the temperature was raised to 150 °C and crystallization was continued for 7 days.

[0181] (1.4) After washing the product, it was dried at 120°C for 16 h and the carrier was collected.

[0182] (2) Active ingredient loading:

[0183] (2.1) Disperse 0.6 g of sodium tetrachloropalladate in 500 mL of deionized water.

[0184] (2.2) Add 100 g of the carrier to the dispersion obtained in step (2.1) for impregnation, continue stirring for 3 hours, and then centrifuge to obtain a wet powder. Wash it three times with water, and then dry it at 50° C. for 12 hours to obtain an unreduced catalyst powder.

[0185] (2.3) The catalyst powder obtained in step (2.2) was calcined in a hydrogen atmosphere at 200° C. for 4 h to obtain a Pd-loaded single-component catalyst, i.e., a catalyst for cyclohexylbenzene synthesis.

[0186] Comparative Example 3

[0187] This comparative example provides a cyclohexylbenzene synthesis catalyst and a preparation method thereof, the preparation method comprising the following steps:

[0188] (1) Preparation of carrier:

[0189] (1.1) Dissolve 100 g of NaOH in 6000 g of deionized water, add 480 g of NaAlO2 and stir to dissolve, then add 1460 g of hexamethylenediamine and stir for 10 min; then add 700 g of boric acid and stir for 10 min, and keep warm in a water bath at 70°C for 2 h.

[0190] (1.2) 5300 g of colloidal silica (Ludox AS-30) was heated to 70° C. in a water bath and slowly dripped into the solution obtained in step (1) under vigorous stirring to form a gel product. The container containing Ludox AS-40 was rinsed with 500 g of water several times and transferred to the sol system.

[0191] (1.3) The obtained gel was stirred for 20 min and transferred to a reactor. The temperature was controlled at 60 °C. After stirring for 40 min, the temperature was raised to 150 °C and crystallization was continued for 7 days.

[0192] (1.4) After washing the product, it was dried at 120°C for 16 h and the carrier was collected.

[0193] (2) First load:

[0194] (2.1) Disperse 50 g of the carrier in 500 mL of deionized water and add 0.8 g of hydrated ruthenium trichloride.

[0195] (2.2) 20 g of PVP with a molecular weight of 8000 was added to the slurry obtained in step (2.1) and stirred for 60 min; then 40 mL of 0.2 mol / L AA solution was added, and the mixture was mixed for 2 h and then centrifuged to obtain a wet powder, which was washed three times with water and then dried at 75 °C for 14 h to obtain a Ru-loaded single-component catalyst.

[0196] (3) Second load:

[0197] (3.1) Disperse 0.6 g of sodium tetrachloropalladate in 500 mL of deionized water.

[0198] (3.2) Add 100 g of Ru-loaded single-component catalyst to the dispersion obtained in step (3.1) for impregnation, continue stirring for 3 hours, and then centrifuge to obtain wet powder, wash three times with water, and then dry at 50°C for 12 hours to obtain unreduced catalyst raw powder.

[0199] (3.3) The catalyst powder obtained in step (3.2) was calcined in a hydrogen atmosphere at 200° C. for 4 h to obtain a dual-component catalyst loaded with both Pd and Ru, i.e., a catalyst for cyclohexylbenzene synthesis.

[0200] Performance Testing

[0201] The catalysts obtained in Examples 1-16 and Comparative Examples 1-3 were used to carry out benzene hydrogenation alkylation to synthesize cyclohexylbenzene. The specific method was as follows: 20 g of the catalyst was loaded into a fixed bed with a loading height-to-diameter ratio of L / d=36.3; the catalyst was activated by heating from 18°C ​​to 180°C at a rate of 1°C / min for 5 h under a hydrogen flow rate of 200 mL / min. After the catalyst was activated, benzene was fed at a rate of 80 g / h, and the hydrogen-to-benzene molar ratio was controlled to be 1:1, and WHSV=4h. -1 , the reaction pressure is 2MPa, and the reaction temperature is 150℃.

[0202] The catalyst was tested for physical properties and the resulting product was analyzed for components. The relevant results are shown in Table 1 below.

[0203] Table 1

[0204]

[0205]

[0206] It can be seen that the present invention realizes the surface modification effect of the second active component on the first active component by loading two specific types of metal active components on the surface of the carrier and limiting the second active component to partially cover the surface of the first active component, thereby effectively regulating the catalyst performance, reducing the selectivity of the by-product cyclohexane, and improving the yield of the target product cyclohexylbenzene, which is conducive to large-scale promotion and application.

[0207] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A surface-modified cyclohexylbenzene synthesis catalyst, characterized in that: The cyclohexylbenzene synthesis catalyst comprises a carrier and a first active component and a second active component supported on the surface of the carrier, wherein the second active component partially covers the surface of the first active component; Wherein, the carrier includes a molecular sieve; the first active component includes Pt and / or Pd, and the second active component includes Ni and / or Ru.

2. The cyclohexylbenzene synthesis catalyst according to claim 1, characterized in that The molecular sieve includes any one of 3A molecular sieve, 4A molecular sieve, MFI molecular sieve or MWW molecular sieve, or a combination of at least two thereof; And / or, the silicon to aluminum molar ratio of the molecular sieve is (5-25):1; And / or, the specific surface area of ​​the molecular sieve is 200-800m 2 / g.

3. The cyclohexylbenzene synthesis catalyst according to claim 1 or 2, characterized in that Taking the mass of the carrier as the calculation basis, the loading amount of the first active component is 0.1-0.35wt%; And / or, based on the mass of the carrier as the calculation basis, the loading amount of the second active component is 0.3-1.5wt%; And / or, the area covered by the second active component on the surface of the first active component accounts for 20%-80%.

4. A method for preparing a cyclohexylbenzene synthesis catalyst as claimed in any one of claims 1 to 3, characterized in that: The preparation method comprises carrier preparation, first loading and second loading performed sequentially; The first load is used to load a first active component onto the surface of the carrier, and the second load is used to load a second active component onto the surface of the carrier.

5. The preparation method according to claim 4, characterized in that: The carrier is prepared by a hydrothermal synthesis method; And / or, the first load and the second load are respectively impregnated.

6. The preparation method according to claim 5, characterized in that: The impregnation solution used for the first loading includes a platinum salt solution and / or a palladium salt solution; Wherein, the solute in the platinum salt solution includes any one of chloroplatinic acid, potassium tetrachloroplatinate or potassium hexachloroplatinate, or a combination of at least two thereof; And / or, the solute in the palladium salt solution includes any one or a combination of at least two of palladium chloride, chloropalladic acid, tetraaminopalladium nitrate or sodium tetrachloropalladate; And / or, the first load is dried and calcined in sequence after impregnation, and the calcination is carried out in an atmosphere of reducing gas, the calcination temperature is 50-400° C., and the calcination time is 1-8 hours.

7. The preparation method according to claim 5, characterized in that: The impregnation solution used for the second loading includes a nickel salt solution and / or a ruthenium salt solution; Wherein, the solute in the nickel salt solution includes any one of nickel chloride, nickel sulfate, nickel nitrite or nickel hydroxide, or a combination of at least two thereof; and / or, the solute in the ruthenium salt solution includes hydrated ruthenium trichloride and / or ruthenium nitrate; And / or, the impregnation solution used for the second load is also mixed with polyvinyl pyrrolidone and / or ascorbic acid; And / or, the second load is dried after impregnation, and the drying temperature is 25-150° C. and the drying time is 8-48 hours.

8. A method for synthesizing cyclohexylbenzene by hydroalkylation of benzene, characterized in that: The method uses the cyclohexylbenzene synthesis catalyst as claimed in any one of claims 1 to 3 to carry out benzene hydroalkylation reaction.

9. The method according to claim 8, characterized in that The liquid phase mass space velocity of the benzene hydroalkylation reaction is 2-6h -1 ; And / or, the molar ratio of hydrogen to benzene in the benzene hydroalkylation reaction is (1-2):

1.

10. The method according to claim 8 or 9, characterized in that: The temperature of the benzene hydroalkylation reaction is 150-200°C; And / or, the pressure of the benzene hydroalkylation reaction is 1-3 MPa.

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