A process for the production of cyclohexylbenzene by benzene hydroalkylation

Abstract

The application discloses a method for preparing cyclohexylbenzene by benzene hydroalkylation. The method comprises the following steps: contacting benzene with a hydroalkylation catalyst to perform a reaction, so as to obtain a hydroalkylation product containing cyclohexylbenzene, wherein the hydroalkylation catalyst comprises a metal component and MCM-22 molecular sieve, wherein the weight ratio of framework aluminum (Al [F] ) of the molecular sieve to non-framework aluminum (Al [EF] ) is 5.0-15.5:1. The method can improve the activity, selectivity and stability of the benzene hydroalkylation reaction.

Description

Technical Field

[0001] This invention belongs to the technical field of catalytic chemistry and chemical engineering, and in particular relates to a method for preparing cyclohexylbenzene by hydrogenation alkylation of benzene. Background Technology

[0002] Cyclohexylbenzene, as a high-value-added fine chemical, can be used as a high-boiling-point solvent, diesel additive, liquid crystal intermediate, and can also be used as an anti-overcharge additive for lithium-ion batteries. With the continuous development of the clean energy industry, it is foreseeable that it will have a large market space in emerging fields such as new chemical materials and new energy.

[0003] The benzene hydrogenation alkylation method directly prepares cyclohexylbenzene from benzene using a bifunctional catalyst. It boasts advantages such as low raw material costs and a simple process, making it promising for large-scale industrial production. However, in actual reactions, deep hydrogenation or secondary alkylation often occurs, generating byproducts such as cyclohexane and methylcyclopentylbenzene, leading to a decrease in the selectivity of cyclohexylbenzene in the final product. Furthermore, coking reactions may occur on the catalyst, affecting its stability and lifespan.

[0004] CN114130421A discloses a benzene hydrogenation alkylation catalyst, its preparation method, and its application. The catalyst comprises inorganic oxides, modified molecular sieves, and a metal component. The preparation method includes: (1) reacting a salt solution containing the metal component with inorganic and / or organic ligands to form a complex solution; (2) mixing the complex solution obtained in step (1) with an alkaline solution to obtain a mixed alkaline solution; (3) adding the mixed alkaline solution obtained in step (2) to a mixture of raw materials for molecular sieve synthesis, and carrying out a crystallization reaction under molecular sieve synthesis conditions to obtain a metal-containing molecular sieve; (4) kneading the metal-containing molecular sieve obtained in step (3) with inorganic oxides, followed by drying and calcination to obtain the hydrogenation alkylation catalyst. In the benzene hydrogenation alkylation reaction, the yield of cyclohexylbenzene using this catalyst needs further improvement.

[0005] CN109772432A discloses a metal-coated catalyst for the selective hydrogenation alkylation of benzene to prepare cyclohexylbenzene, as well as its preparation and application methods. The catalyst consists of an active component, a molecular sieve, and a framework. The preparation method involves first loading the active component onto an H-type molecular sieve, performing a reduction reaction, and then introducing the molecular sieve loaded with the active component into a silica-alumina gel for crystallization. This is followed by another H-exchange and reduction reaction to obtain a metal-coated bifunctional catalyst, where the molecular sieve loaded with the active component is encapsulated within the framework. However, this method is complex, and the multiple reduction reactions increase costs.

[0006] In summary, the development and preparation of catalysts with high activity, selectivity and stability are of great significance for the large-scale production of cyclohexylbenzene. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a method for preparing cyclohexylbenzene by the hydrogenation alkylation of benzene. This method improves the activity, selectivity, and stability of the benzene hydrogenation alkylation reaction.

[0008] This invention provides a method for preparing cyclohexylbenzene by hydrogenation alkylation of benzene, comprising: reacting benzene with a hydrogenation alkylation catalyst to obtain a hydrogenation product containing cyclohexylbenzene, wherein the hydrogenation alkylation catalyst comprises a metal component and an MCM-22 molecular sieve, wherein the molecular sieve has an aluminum (Al) framework. [F] ) and non-framework aluminum (Al) [EF] The weight ratio of ) is 5.0 to 15.5:1.

[0009] In the above technical solution, the hydrogenation alkylation reaction conditions are as follows: reaction temperature is 100–200℃, preferably 135–175℃; pressure is 0.5–2.0 MPa, preferably 0.7–1.5 MPa; and benzene mass hourly space velocity is 0.5–2.0 h⁻¹. -1 Preferably, it is 0.6 to 1.2 hours. -1 The molar ratio of hydrogen to benzene is 0.1 to 5.0, preferably 0.3 to 1.0.

[0010] In the above technical solution, the framework aluminum (Al) of the MCM-22 molecular sieve [F] ) and non-framework aluminum (Al) [EF] The weight ratio of the components is 5.0 to 15.5:1, preferably 7.0 to 11.0:1. More specific non-limiting weight ratios can be 5.0, 6.0, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 12.0, 13.0, 14.0, 15.0, 15.5, etc.

[0011] In the above technical solution, the outer surface of the MCM-22 molecular sieve contains semi-supercage aluminum (Al). (61) ) and framework aluminum (Al) [F] The weight ratio is 0.20 to 0.60:1, preferably 0.22 to 0.42:1, and more specific non-limiting weight ratios can be 0.22, 0.23, 0.24, 0.25, 0.28, 0.30, 0.32, 0.35, 0.38, 0.40, 0.42, 0.45, 0.48, 0.50, 0.55, 0.60, etc.

[0012] In the above technical solution, preferably, the SiO2 / Al2O3 molar ratio of the molecular sieve is 15-60, more preferably 15-45.

[0013] In the above technical solution, preferably, the metal component in the catalyst is selected from at least one of Ru, Pd, and Pt.

[0014] In the above technical solution, preferably, the metal component in the catalyst accounts for 0.02% to 1.0% of the molecular sieve mass, more preferably 0.05% to 0.30%, and even more preferably 0.08% to 0.25% by mass fraction.

[0015] In the above technical solution, the micropore volume of the catalyst is 0.10–0.30 cm³. 3 ·g -1 The mesopore volume is 0.30–0.65 cm³. 3 ·g -1 Specific surface area is 300-650 m² 2 ·g -1 Preferably, the catalyst has a micropore volume of 0.11–0.22 cm³. 3 ·g -1 The mesopore volume is 0.40–0.65 cm³. 3 ·g -1 Specific surface area is 350-500 m² 2 ·g -1 .

[0016] In the above technical solution, the preparation method of the hydrogenation alkylation catalyst includes:

[0017] (1) A mixture A is obtained by contacting silicon source, aluminum source, alkali source, water, template agent and stabilizer, and then crystallizing it to obtain a molecular sieve;

[0018] (2) The molecular sieve obtained in step (1) is impregnated with an impregnation solution containing metal components, and then dried, calcined, exchanged with ammonium, and reduced to obtain the hydrogenation alkylation catalyst.

[0019] In the above technical solution, preferably, the silicon source in step (1) is one or more of tetraethyl orthosilicate, tetraethoxysilane, alkaline silica sol, silica fume, sodium silicate, and silicic acid. The aluminum source is one or more of sodium aluminate, boehmite, aluminum isopropoxide, aluminum sulfate, and aluminum chloride. The alkali source is one or more of sodium hydroxide and potassium hydroxide. The template agent is one or more of hexamethyleneimine, piperidine, ethylenediamine, cyclohexylamine, and dimethylcyclohexylamine.

[0020] In the above technical solution, the stabilizer mentioned in step (1) is selected from at least one of carbonyl-nitroamide compounds, and the structural formula of the carbonyl-nitroamide compound is as follows: R1, R2, and R3 are each independently selected from hydrogen atoms or organic groups, wherein R1, R2, and R3 are each independently selected from hydrogen atoms, ethyl, cyclohexyl, piperidinyl, pyridinyl, pyrimidinyl, methylpiperidinyl, methylpyridinyl, or methylpyrimidinyl.

[0021] In the above technical solution, preferably, the stabilizer is selected from at least one of 4-piperidinecarboxamide, N-cyclohexylcarboxamide, N-ethylcarboxamide, 2-pyridinecarboxamide, and 6-methylnicotinamide.

[0022] In the above technical solution, preferably, in step (1), the molar ratio of silicon source (SiO2), aluminum source (Al2O3), alkali source, water, template agent and stabilizer is 1:(0.01~0.10):(0.02~0.50):(8~25):(0.05~0.5):(0.01~0.30), preferably 1:(0.01~0.07):(0.05~0.30):(10~20):(0.1~0.5):(0.02~0.10).

[0023] In the above technical solution, preferably, the crystallization conditions in step (1) are dynamic crystallization under closed conditions, with a crystallization temperature of 90-190℃ and a crystallization time of 20-120 hours. The dynamic crystallization is carried out under stirring conditions, preferably with a stirring speed of 10-50 rpm.

[0024] In the above technical solution, preferably, the crystallization treatment in step (1) can be followed by conventional post-processing steps in the art: separation, washing, drying, and calcination. The separation is performed by centrifugation, and the washing is done with deionized water until the pH of the separated solid is approximately 7.0–8.0. The drying conditions are 100–180℃ for 5–20 hours. The calcination temperature is 450–600℃, the calcination time is 2–6 hours, and the calcination atmosphere is an oxygen-containing gas, such as air.

[0025] In the above technical solution, preferably, in step (2), the metal component source in the impregnation solution containing metal components can be a soluble metal salt, preferably a metal chloride.

[0026] In the above technical solution, preferably, in step (2), the impregnation method is equal volume impregnation, the impregnation temperature is 20-60℃, and the impregnation time is 6-24 hours.

[0027] In the above technical solution, preferably, in step (2), the drying conditions are 90-120℃ and the drying time is 6-12h. The calcination conditions are an oxygen-containing atmosphere (such as air), the calcination temperature is 300-500℃, and the calcination time is 2-5h. The ammonium exchange conditions are to treat with an ammonium salt solution with a mass concentration of 2%-10% at 20-70℃ for 1-5h, and to continuously exchange 2-5 times. The ammonium salt is at least one of ammonium sulfate, ammonium acetate, or ammonium nitrate. During the ammonium exchange, the amount of ammonium salt solution added is 10:1 to 3:1 in liquid-to-solid volume ratio.

[0028] In the above technical solution, preferably, in step (2), the reducing atmosphere is a mixture of nitrogen and hydrogen, wherein the volume ratio of nitrogen to hydrogen is 9:1 to 7:3. The reduction temperature is preferably 250 to 450°C, and the reduction time is preferably 2 to 8 hours.

[0029] In the above technical solution, the hydrogenation alkylation catalyst can be in any physical form, such as powder, granules, or molded products, such as flakes, strips, or clover-shaped. These physical forms can be obtained in any manner conventionally known in the art, without particular limitation. When the hydrogenation alkylation catalyst is shaped as needed, the specific preparation method can be: impregnating a molecular sieve with an impregnation solution containing metal components, then mixing and shaping it with a binder, followed by drying, calcination, ammonium exchange, and reduction to obtain the hydrogenation alkylation catalyst. The binder can be at least one of alumina, silica, and titanium dioxide. The amount of binder added accounts for 10% to 40% of the molecular sieve mass.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1. The inventors discovered through research that the hydrogenation alkylation catalyst uses MCM-22 molecular sieve with specific skeletal aluminum content and distribution as the support and alkylation active component, and noble metals as the hydrogenation active component. This allows for the improvement of benzene conversion and cyclohexylbenzene product selectivity under relatively low metal loading and relatively mild reaction conditions.

[0032] 2. This invention introduces a stabilizer during the preparation of molecular sieves to effectively limit and regulate the distribution of framework aluminum in the molecular sieves. After loading the metal, it can achieve efficient synergistic cooperation between the metal active center and the molecular sieve alkylation center, jointly improving the performance of the catalyst. In particular, it has good cyclohexylbenzene selectivity in the hydrogenation alkylation reaction of benzene. Attached Figure Description

[0033] Figure 1 The XRD pattern of the molecular sieve obtained in Example 1 of this invention;

[0034] Figure 2The Al-NMR spectrum of the molecular sieve obtained in Example 1 of this invention;

[0035] Figure 3 The XRD pattern of the molecular sieve obtained in Comparative Example 1 of this invention is shown.

[0036] Figure 4 The image shows the Al-NMR spectrum of the molecular sieve obtained in Comparative Example 1 of this invention. Detailed Implementation

[0037] To provide a clearer understanding of the technical features, objectives, and beneficial effects of the present invention, the present invention will be described in detail below with reference to specific embodiments. However, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0038] In this invention, the distribution of aluminum species in the molecular sieve is determined by analysis. 27 The Al MAS NMR results were obtained using a JEOL 500MHz (11.7T) spectrometer with a 3.2mm HX MAS NMR probe at a rotation speed of 18kHz. The spectrum was acquired at a resonance frequency of 130.3MHz. Chemical shifts were referenced to a 1mol / L Al(NO3)3 solution (δ = 0ppm). The values ​​of δ = 0ppm and 54ppm in the spectrum correspond to octahedral coordinated non-framework aluminum (Al2O3)2, respectively. [EF] ) and four-coordinated framework aluminum (Al [F] The characteristic peaks of ) can be used to determine the aluminum distribution at different tetrahedral sites by performing peak fitting calculations on the latter, where the Al distribution at δ = 50 ppm is determined. (50) Al corresponding to the 12MR supercage of molecular sieve F Distribution, Al deposition at δ = 56 ppm (Al (56) ) corresponds to Al in a sinusoidal channel [F] Distribution, Al deposition at δ = 61 ppm (Al (61) ) Corresponding to the Al on the outer surface of the 12MR semi-supercage [F] distributed.

[0039] In this invention, a Micromeritics ASAP-2000 physical adsorption instrument was used to determine the N2 adsorption-desorption isotherm at 77K. Before the test, the sample was degassed and vacuum-treated at 573K for 4h. The total pore volume and specific surface area were calculated using the BET equation, and the micropore volume was determined using the t-plot curve method. The difference between the total pore volume and the micropore volume is the mesopore volume.

[0040] In this invention, the SiO2 / Al2O3 molar ratio of the molecular sieve was obtained by ICP testing, which was performed using a Varian 725-ES ICP-AES analyzer.

[0041]

Example 1

[0042] This embodiment is used to synthesize a hydrogenation alkylation catalyst, and the specific preparation process is as follows:

[0043] (1) Dissolve 11.3g sodium aluminate (Al2O3 45.0wt%) and 6.0g sodium hydroxide in 234.0g water and stir continuously until dissolved. Then add 24.8g hexamethyleneimine and 6.4g 4-piperidinecarboxamide and stir for 30min. Then add 208.3g tetraethoxysilane. The molar ratio of the reactants is tetraethoxysilane (SiO2): sodium aluminate (Al2O3): NaOH: water: hexamethyleneimine: stabilizer = 1:0.05:0.15:13:0.25:0.05. After stirring for another 30 minutes until the mixture is homogeneous, it is placed in a stainless steel reactor with a polytetrafluoroethylene liner and crystallized at 160°C and 30 rpm for 72 hours in a homogeneous reactor. The resulting mixture is then centrifuged, washed with deionized water to pH 7, dried in a 150°C oven for 8 hours, and calcined in air at 500°C for 5 hours to obtain molecular sieve Al.

[0044] (2) Take 1.0g of the A1 molecular sieve obtained in step (1), and continuously add deionized water until the molecular sieve is just saturated and moistened. Calculate that the water absorption of 1.0g of molecular sieve is 1.7mL. Add 17mL of 1.0mg / mL RuCl3 aqueous solution dropwise to 10g of the molecular sieve prepared in step (1), and use an oscillator to make the metal salt solution evenly distributed on the molecular sieve. After standing at 30℃ for 12h, add 3.0g of alumina and mix well. Knead and shape into strips, dry at 120℃ for 12h, and then calcine in air atmosphere at 350℃ for 3h. Treat with 5% ammonium acetate solution at 30℃ for 2h according to the liquid-to-solid volume ratio of 10:1, and exchange continuously 3 times. Then place in a tube furnace, introduce a mixed gas of nitrogen and hydrogen in a volume ratio of 9:1, and reduce at 300℃ for 2h to obtain the target catalyst B1. In the catalyst, Ru accounts for 0.17% of the molecular sieve mass.

[0045] The XRD pattern of the prepared A1 molecular sieve is as follows: Figure 1 As shown.

[0046] The Al-NMR spectrum of the prepared A1 molecular sieve is as follows: Figure 2 As shown in Table 1, the distribution of aluminum species is shown in the table.

[0047] The micropore volume of catalyst B1 was determined to be 0.16 cm³. 3 ·g -1 The mesopore volume is 0.59 cm³. 3 ·g -1 Specific surface area is 435 m² 2·g -1 .

[0048]

Example 2

[0049] This embodiment is used to synthesize a hydrogenation alkylation catalyst, and the specific preparation process is as follows:

[0050] (1) Dissolve 11.3g sodium aluminate (Al2O3 45.0wt%) and 4.0g sodium hydroxide in 360.0g water and stir continuously until dissolved. Then add 70.1g hexamethyleneimine and 9.8g 2-pyridine amide and stir for 30min. Then add 208.3g tetraethoxysilane. The molar ratio of the reactants is tetraethoxysilane (SiO2): sodium aluminate (Al2O3): NaOH: water: hexamethyleneimine: stabilizer = 1:0.05:0.10:20:0.5:0.08. After stirring for another 30 minutes until the mixture is homogeneous, it is placed in a stainless steel reactor with a polytetrafluoroethylene liner and crystallized at 170°C and 20 rpm for 60 hours in a homogeneous reactor. The resulting mixture is then centrifuged, washed with deionized water to pH 7, dried in an oven at 130°C for 10 hours, and calcined in air at 550°C for 4 hours to obtain molecular sieve A2.

[0051] (2) Take 1.0g of A2 molecular sieve obtained in step (1), and continuously add deionized water until the molecular sieve is just saturated and moistened. Calculate the water absorption of 1.0g of molecular sieve to be 1.7mL. Add 17mL of 1.3mg / mL PdCl2 aqueous solution dropwise to 10g of molecular sieve obtained in step (1), and use an oscillator to make the metal salt solution evenly distributed on the molecular sieve. After standing at 20℃ for 16h, add 2.5g of alumina and mix well. Knead and shape into a clover shape, dry at 110℃ for 10h, and then calcine in air atmosphere at 300℃ for 4h. Treat with 7% ammonium sulfate solution at 20℃ for 1h according to the liquid-to-solid volume ratio of 8:1, and exchange 4 times continuously. Then place in a tube furnace, introduce a mixed gas of nitrogen and hydrogen in a volume ratio of 7:1, and reduce at 280℃ for 3h to obtain the target catalyst B2. In the catalyst, Pd accounts for 0.22% of the molecular sieve mass.

[0052] The XRD pattern of molecular sieve A2 indicates that it is MCM-22 molecular sieve.

[0053] The distribution of aluminum species obtained by Al-NMR testing of molecular sieve A2 and peak fitting is shown in Table 1.

[0054] The micropore volume of catalyst B2 was determined to be 0.14 cm³. 3 ·g -1 The mesopore volume is 0.53 cm³. 3 ·g -1Specific surface area is 417 m² 2 ·g -1 .

[0055]

Example 3

[0056] This embodiment is used to synthesize a hydrogenation alkylation catalyst, and the specific preparation process is as follows:

[0057] (1) Dissolve 6.8g sodium aluminate (Al2O3 45.0wt%) and 4.8g sodium hydroxide in 270.0g water. After stirring continuously until dissolved, add 17.0g piperidine and 4.1g 6-methylnicotinamide. After stirring for 30min, add 208.3g tetraethoxysilane. The molar ratio of the reactants is tetraethoxysilane (SiO2): sodium aluminate (Al2O3): NaOH: water: piperidine: stabilizer = 1:0.03:0.12:15:0.2:0.03. Continue stirring for 30min until uniformly mixed. Then, put it into a stainless steel reactor with a polytetrafluoroethylene liner and place it in a homogeneous reactor for crystallization at 150℃ and 25rpm for 96 hours. After that, centrifuge the obtained mixture, wash it with deionized water to pH 7, dry it in an oven at 140℃ for 9h, and calcine it in air at 550℃ for 6h to obtain molecular sieve A3.

[0058] (2) Take 1.0g of the A3 molecular sieve obtained in step (1), and continuously add deionized water until the molecular sieve is just saturated and moistened. Calculate that the water absorption of 1.0g of molecular sieve is 1.7mL. Add 17mL of 0.7mg / mL PtCl4 aqueous solution dropwise to 10g of the molecular sieve prepared in step (1). During this process, use an oscillator to ensure that the metal salt solution is evenly distributed on the molecular sieve. Let it stand at 40℃ for 10h, add 3.5g of alumina and mix well. Knead and shape into strips, dry at 100℃ for 10h, and then calcine in air at 400℃ for 2h. Treat with 8% ammonium acetate solution at 40℃ for 1h according to the liquid-to-solid volume ratio of 6:1, and exchange 4 times continuously. Then place it in a tube furnace, introduce a mixed gas of nitrogen and hydrogen in a volume ratio of 8:1, and reduce at 300℃ for 3h to obtain the target catalyst B3. In the catalyst, Pt accounts for 0.12% of the molecular sieve mass.

[0059] The XRD pattern of molecular sieve A3 indicates that it is MCM-22 molecular sieve.

[0060] The distribution of aluminum species obtained by Al-NMR testing and peak fitting of molecular sieve A3 is shown in Table 1.

[0061] The micropore volume of catalyst B3 was determined to be 0.13 cm³. 3 ·g -1 The mesopore volume is 0.50 cm³. 3 ·g-1 Specific surface area is 408m² 2 ·g -1 .

[0062]

Example 4

[0063] This embodiment is used to synthesize a hydrogenation alkylation catalyst, and the specific preparation process is as follows:

[0064] (1) Dissolve 7.0g of boehmite and 8.4g of potassium hydroxide in 216.0g of water and stir continuously until dissolved. Then add 24.8g of hexamethyleneimine and 3.7g of N-ethylformamide. After stirring for 30min, add 150.0g of silica sol. The molar ratio of the reactants is: silica sol (SiO2): boehmite (Al2O3): KOH: water: hexamethyleneimine: stabilizer = 1:0.06:0.15:12:0.25:0.05. Continue stirring for 30min until uniformly mixed. Then, put it into a stainless steel reactor with a polytetrafluoroethylene liner and place it in a homogeneous reactor for crystallization at 175℃ and 15rpm for 40 hours. After that, centrifuge the resulting mixture, wash it with deionized water to pH 7, dry it in an oven at 120℃ for 12h, and calcine it in air at 480℃ for 5h to obtain A4 molecular sieve.

[0065] (2) Take 1.0g of A4 molecular sieve obtained in step (1), and continuously add deionized water until the molecular sieve is just saturated and moistened. Calculate that the water absorption of 1.0g of molecular sieve is 1.7mL. Add 17mL of 1.0mg / mL RuCl3 aqueous solution dropwise to 10g of molecular sieve obtained in step (1), and use an oscillator to make the metal salt solution evenly distributed on the molecular sieve. After standing at 30℃ for 10h, add 2.5g of alumina and mix well. Knead and shape into strips, dry at 120℃ for 8h, and then calcine in air atmosphere at 450℃ for 2h. According to the liquid-solid volume ratio of 5:1, treat with 9% ammonium acetate solution at 30℃ for 1h, and repeat the treatment 4 times. Then place in a tube furnace, introduce a mixed gas of nitrogen and hydrogen in a volume ratio of 6:1, and reduce at 350℃ for 2h to obtain the target catalyst B4. In the catalyst, Ru accounts for 0.17% of the molecular sieve mass.

[0066] The XRD pattern of molecular sieve A4 indicates that it is MCM-22 molecular sieve.

[0067] The distribution of aluminum species obtained by Al-NMR testing and peak fitting of molecular sieve A4 is shown in Table 1.

[0068] The micropore volume of catalyst B4 was determined to be 0.12 cm³. 3 ·g -1 The mesopore volume is 0.48 cm³. 3 ·g-1 Specific surface area is 395m² 2 ·g -1 .

[0069]

Example 5

[0070] This embodiment is used to synthesize a hydrogenation alkylation catalyst, and the specific preparation process is as follows:

[0071] (1) Dissolve 10.2g aluminum isopropoxide and 4.5g NaOH in 324.0g water, and continue stirring until dissolved. Then add 24.8g hexamethyleneimine and 6.4g N-cyclohexylformamide, and stir for 30min. Then add 65.0g silica. The molar ratio of the reactants is silica (SiO2): aluminum isopropoxide (Al2O3): NaOH: water: hexamethyleneimine: stabilizer = 1:0.05:0.15:18:0.25:0.05. Continue stirring for 30min until the mixture is homogeneous. Then put it into a stainless steel reactor with a polytetrafluoroethylene liner and place it in a homogeneous reactor for crystallization at 160℃ and 30rpm for 72 hours. After that, centrifuge the resulting mixture, wash it with deionized water to pH 7, and then dry it in an oven at 150℃ for 8h. Then calcine it in air at 500℃ for 5h to obtain A5 molecular sieve.

[0072] (2) Take 1.0g of A5 molecular sieve obtained in step (1), and continuously add deionized water until the molecular sieve is just saturated and moistened. Calculate that the water absorption of 1.0g of molecular sieve is 1.7mL. Add 17mL of 1.2mg / mL RuCl3 aqueous solution dropwise to 10g of molecular sieve obtained in step (1). During this process, use an oscillator to ensure that the metal salt solution is evenly distributed on the molecular sieve. After standing at 30℃ for 12h, add 2g of silicon dioxide and mix well. Knead and shape into strips, dry at 120℃ for 12h, and then calcine in air at 350℃ for 3h. According to the liquid-to-solid volume ratio of 10:1, treat with 5% ammonium acetate solution at 30℃ for 2h, and exchange continuously 3 times. Then place in a tube furnace, introduce a mixed gas of nitrogen and hydrogen in a volume ratio of 9:1, and calcine at 300℃ for 2h to obtain the target catalyst B5. In the catalyst, Ru accounts for 0.2% of the molecular sieve mass.

[0073] The XRD pattern of molecular sieve A5 indicates that it is MCM-22 molecular sieve.

[0074] The distribution of aluminum species obtained by Al-NMR testing and peak fitting of molecular sieve A5 is shown in Table 1.

[0075] The micropore volume of catalyst B5 was determined to be 0.15 cm³. 3 ·g -1 The mesopore volume is 0.46 cm³. 3 ·g-1 Specific surface area is 411 m² 2 ·g -1 .

[0076] Comparative Example 1

[0077] Compared with Example 1, this comparative example did not add a stabilizer, but all other steps were the same. The specific process is as follows:

[0078] (1) Dissolve 11.3g of sodium aluminate (Al2O3 45.0wt%) and 6.0g of sodium hydroxide in 234.0g of water. After stirring continuously until dissolved, add 24.8g of hexamethyleneimine and stir for 30min. Then add 208.3g of tetraethoxysilane. The molar ratio of the reactants is tetraethoxysilane (SiO2): sodium aluminate (Al2O3): NaOH: water: hexamethyleneimine = 1:0.05:0.15:13:0.25. Continue stirring for 30min until homogeneous. Then, put it into a stainless steel reactor with a polytetrafluoroethylene liner and place it in a homogeneous reactor for crystallization at 160℃ and 30rpm for 72 hours. After that, centrifuge the resulting mixture, wash it with deionized water to pH 7, and then dry it in an oven at 150℃ for 8h. Then, calcine it in air at 500℃ for 5h to obtain D1 molecular sieve for later use.

[0079] (2) Take 1g of the D1 molecular sieve obtained in step (1), and continuously add deionized water until the molecular sieve is just saturated and moistened. Calculate that the water absorption of 1g of molecular sieve is 1.7mL. Add 17mL of 1.0mg / mL RuCl3 aqueous solution dropwise to 10g of the molecular sieve prepared in step (1). During this process, use an oscillator to ensure that the metal salt solution is evenly distributed on the molecular sieve. After standing at 30℃ for 12h, add 3g of alumina and mix well. Knead and shape into strips, dry at 120℃ for 12h, and then calcine in air at 350℃ for 3h. Treat with 5% ammonium acetate solution at 30℃ for 2h according to the liquid-to-solid volume ratio of 10:1, and exchange continuously 3 times. Then place it in a tube furnace, introduce a mixed gas of nitrogen and hydrogen in a volume ratio of 9:1, and heat to 300℃ at a heating rate of 2℃ / min. After reduction for 2h, the target catalyst B6 is obtained. In the catalyst, Ru accounts for 0.17% of the molecular sieve mass.

[0080] The XRD pattern of the prepared D1 molecular sieve is as follows: Figure 3 As shown.

[0081] The Al-NMR spectrum of the prepared D1 molecular sieve is as follows: Figure 4 As shown in Table 1, the distribution of aluminum species obtained by peak fitting is shown in Table 1.

[0082] The micropore volume of catalyst B6 was determined to be 0.13 cm³. 3 ·g-1 The mesopore volume is 0.46 cm³. 3 ·g -1 Specific surface area is 392m² 2 ·g -1 .

[0083] Comparative Example 2

[0084] Compared with Example 1, this comparative example did not have metal loading, but all other steps were the same. The specific process is as follows:

[0085] (1) Dissolve 11.3g sodium aluminate (Al2O3 45.0wt%) and 6.0g sodium hydroxide in 234.0g water. After stirring continuously until dissolved, add 24.8g hexamethyleneimine and 6.4g 4-piperidinecarboxamide. After stirring for 30min, add 208.3g tetraethoxysilane. The molar ratio of the reactants is tetraethoxysilane (SiO2): sodium aluminate (Al2O3): NaOH: water: hexamethyleneimine: stabilizer = 1:0.05:0.15:13:0.25:0.05. After stirring for another 30 minutes until the mixture is homogeneous, it is placed in a stainless steel reactor with a polytetrafluoroethylene liner and crystallized at 160°C and 30 rpm for 72 hours in a homogeneous reactor. The resulting mixture is then centrifuged, washed with deionized water to pH 7, dried in a 150°C oven for 8 hours, and calcined in air at 500°C for 5 hours to obtain D2 molecular sieve.

[0086] (2) Take 10g of molecular sieve and add 3.0g of alumina to mix evenly, knead into strip shape, dry at 120℃ for 12h, and then calcine in air atmosphere at 350℃ for 3h; treat with ammonium acetate solution with mass concentration of 5% at 30℃ for 2h according to liquid-solid volume ratio of 10:1, and exchange continuously 3 times; then place in tube furnace, introduce mixed gas with nitrogen and hydrogen volume ratio of 9:1, reduce at 300℃ for 2h to obtain target catalyst B7.

[0087] The micropore volume of catalyst B7 was determined to be 0.16 cm³. 3 ·g -1 The mesopore volume is 0.60 cm³. 3 ·g -1 Specific surface area is 440m² 2 ·g -1 .

[0088]

Examples 6-10

[0089] Catalysts B1-B5 prepared in Examples 1-5 were respectively applied to the hydrogenation alkylation of benzene to cyclohexylbenzene, wherein the reaction temperature was 140°C, the reaction pressure was 1 MPa, and the benzene mass hourly space velocity was 1 h⁻¹. -1The molar ratio of hydrogen to benzene was 0.33. The conversion rate of benzene and the content of key products were tested. The results after 40 hours of reaction are shown in Table 2.

[0090] Comparative Examples 3-4

[0091] Catalysts B6-B7 prepared in Comparative Examples 1 and 2 were applied to the hydrogenation alkylation of benzene to cyclohexylbenzene, respectively, at a reaction temperature of 140 °C, a reaction pressure of 1 MPa, and a benzene mass hourly space velocity of 1 h⁻¹. -1 The molar ratio of hydrogen to benzene was 0.33. The results after 40 hours of reaction are shown in Table 2.

[0092]

Example 11

[0093] The catalyst B1 prepared in Example 1 was applied to the hydrogenation alkylation of benzene to cyclohexylbenzene, wherein the reaction temperature was 150°C, the reaction pressure was 0.9 MPa, and the benzene mass hourly space velocity was 0.8 h⁻¹. -1 The molar ratio of hydrogen to benzene was 0.4. The conversion rate of benzene and the content of key products were tested. The results after 40 hours of reaction are shown in Table 2.

[0094] Table 1 shows the distribution of aluminum species and the silicon-to-aluminum ratio in the molecular sieves obtained in each example.

[0095] A1 9.5 0.28 19.81 A2 9.0 0.25 19.93 A3 8.5 0.29 32.80 A4 8.9 0.25 16.67 A5 7.8 0.27 19.83 D1 4.4 0.20 20.58 D2 9.5 0.28 19.81

[0096] Table 2 shows the reaction results of applying the obtained catalysts to the hydrogenation alkylation of benzene to cyclohexylbenzene.

[0097]

[0098] Single-cycle life test

[0099] The catalysts B1-B6 prepared in Examples 1-5 and Comparative Example 1 were tested for their single-pass lifetimes in the benzene hydrogenation alkylation reaction under ultra-high benzene space velocity reaction conditions: reaction temperature 140°C, reaction pressure 1 MPa, and benzene mass hourly space velocity 8 h⁻¹. -1 The molar ratio of hydrogen to benzene was 0.33. The single-pass lifetime refers to the time elapsed from the start of the reaction until the conversion rate of benzene drops to 40% of the initial conversion rate. The test results are shown in Table 3.

[0100] Table 3

[0101] B1 156 B2 148 B3 139 B4 154 B5 145 B6 82

[0102] The embodiments described above are merely detailed descriptions of the technical solutions of the present invention, but the present invention is not limited to the above embodiments, that is, the present invention does not depend on the steps described in the above embodiments to be implemented. In summary, any improvements made to the present invention by those skilled in the art, including the substitution of the raw materials and additives described in the present invention, the selection of specific implementation methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing cyclohexylbenzene by hydrogenation alkylation of benzene, comprising: Benzene reacts with a hydroalkylation catalyst to yield a hydrogenation product containing cyclohexylbenzene. The hydroalkylation catalyst comprises a metal component and an MCM-22 molecular sieve, wherein the MCM-22 molecular sieve has an aluminum (Al) framework. [F] ) and non-framework aluminum (Al) [EF] The weight ratio of aluminum (Al) to aluminum (Al) in the outer surface of the MCM-22 molecular sieve is 5.0~15.5:1; (61) ) and framework aluminum (Al) [F] The weight ratio is 0.22~0.60:1; In the catalyst, the metal component is selected from at least one of Ru, Pd, and Pt; The catalyst, by mass fraction, has a metal component accounting for 0.02% to 1.0% of the molecular sieve mass.

2. The method according to claim 1, characterized in that, The hydrogenation alkylation reaction conditions are as follows: reaction temperature 100–200 °C, pressure 0.5–2.0 MPa, and benzene mass hourly space velocity (WHSV) 0.5–2.0 h⁻¹. -1 The molar ratio of hydrogen to benzene is 0.1 to 5.

0.

3. The method according to claim 2, characterized in that, The hydrogenation alkylation reaction conditions are as follows: reaction temperature 135–175 °C, pressure 0.7–1.5 MPa, and benzene mass hourly space velocity (WHSV) 0.6–1.2 h⁻¹. -1 The molar ratio of hydrogen to benzene is 0.3 to 1.

0.

4. The method according to claim 1, characterized in that, The framework aluminum (Al) of the MCM-22 molecular sieve [F] ) and non-framework aluminum (Al) [EF] The weight ratio of ) is 7.0~11.0:

1.

5. The method according to claim 1, characterized in that, The outer surface of the MCM-22 molecular sieve contains semi-supercage aluminum (Al). (61) ) and framework aluminum (Al) [F] The weight ratio is 0.22~0.42:

1.

6. The method according to claim 1, characterized in that, The SiO2 / Al2O3 molar ratio of the molecular sieve is 15~60.

7. The method according to claim 6, characterized in that, The SiO2 / Al2O3 molar ratio of the molecular sieve is 15~45.

8. The method according to claim 1, characterized in that, The catalyst, by mass fraction, has a metal component accounting for 0.05% to 0.30% of the molecular sieve mass.

9. The method according to claim 8, characterized in that, The catalyst, by mass fraction, comprises a metal component accounting for 0.08% to 0.25% of the molecular sieve mass.

10. The method according to claim 1, characterized in that, The catalyst has a micropore volume of 0.10~0.30 cm³. 3 ·g -1 The mesopore volume is 0.30~0.65 cm³. 3 ·g -1 Specific surface area is 300~650 m² 2 ·g -1 .

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