Hydroalkylation catalyst and preparation method thereof

Abstract

The invention discloses a hydroalkylation catalyst and a preparation method thereof. The catalyst comprises a metal component and a molecular sieve, wherein the weight ratio of framework aluminum (Al [F]) to non-framework aluminum (Al [EF]) of the molecular sieve is (5.0-15.0): 1. The catalyst provided by the invention is especially suitable for benzene hydroalkylation reaction, and can improve the activity of benzene hydroalkylation reaction and the selectivity and stability of cyclohexylbenzene.

Description

Technical Field

[0001] The invention belongs to the technical field of catalytic chemistry and chemical engineering, and in particular relates to a hydroalkylation catalyst and a preparation method thereof. Background Art

[0002] Cyclohexylbenzene, the product of benzene hydroalkylation, can be used as a high-boiling point solvent, liquid crystal intermediate, and anti-overcharge additive for lithium-ion battery electrolyte. It can also produce phenol and cyclohexanone through oxidation-decomposition reaction. It is a high-value-added chemical with market potential.

[0003] The benzene hydroalkylation method is a one-step process to directly produce cyclohexylbenzene from benzene. The synthesis process is simple, green and low-cost, and has application prospects. However, in the actual reaction process, the yield of cyclohexylbenzene is limited due to the existence of side reactions such as deep hydrogenation and secondary alkylation.

[0004] CN114130424A discloses a hydroalkylation catalyst and its preparation method and application. The catalyst comprises an inorganic oxide, a modified molecular sieve and a metal component, wherein the ratio of the acid center density to the micropore volume of the modified molecular sieve is 1000-2000 μmol / cm 3 The preparation method of the modified molecular sieve includes: the basic molecular sieve is subjected to subsequent hydrothermal treatment and acid-base treatment to optimize the ratio of the acid center density to the molecular sieve micropore volume. The catalyst is used in the benzene hydroalkylation reaction and has good cyclohexylbenzene selectivity, while significantly improving the selectivity of dicyclohexylbenzene.

[0005] CN109772432A discloses a metal-coated catalyst for preparing cyclohexylbenzene by selective hydroalkylation of benzene, and its preparation method and use method. The catalyst is composed of an active component, a molecular sieve and a skeleton. The preparation method is to first load the active component on an H-type molecular sieve, perform a reduction reaction, then introduce the molecular sieve loaded with the active component into a silica-alumina gel for crystallization, and perform H exchange and reduction reaction again to obtain a metal-coated bifunctional catalyst, that is, the molecular sieve loaded with the active component is coated inside the skeleton, but the process of this method is complicated, and multiple reduction reactions increase the cost.

[0006] In summary, how to more economically synthesize molecular sieve catalysts with efficient coupling of hydrogenation and alkylation functions and improve the yield of cyclohexylbenzene is a research hotspot in this field. Summary of the invention

[0007] In view of the shortcomings of the prior art, the present invention provides a hydroalkylation catalyst and a preparation method thereof. The catalyst of the present invention is used in the benzene hydroalkylation reaction and can improve the activity of the benzene hydroalkylation reaction, the selectivity and stability of cyclohexylbenzene.

[0008] The first aspect of the present invention provides a hydroalkylation catalyst, the catalyst comprising a metal component and a molecular sieve, wherein the framework aluminum (Al [F] ) and non-framework aluminum (Al [EF] ) by weight ratio is 5.0-15.0:1.

[0009] In the above technical solution, preferably, the outer surface of the molecular sieve has aluminum (Al (61) ) and skeleton aluminum (Al [F] )The weight ratio is 0.22~0.50:1.

[0010] In the above technical solution, the framework aluminum (Al [F] ) and non-framework aluminum (Al [EF] ) by weight ratio is 5.0-15.0:1, preferably 7.0-11.0:1, further preferably 7.0-10.0:1, and a more specific non-limiting weight ratio can be 5.0, 6.5, 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 and the like.

[0011] In the above technical solution, the outer surface of the molecular sieve is semi-super cage aluminum (Al (61) ) and skeleton aluminum (Al [F] ) weight ratio is 0.22-0.50:1, preferably 0.22-0.42:1, further preferably 0.25-0.30:1, and more specifically, the non-limiting weight ratio 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 and the like.

[0012] In the above technical solution, preferably, the molecular sieve is a silicon-aluminum molecular sieve with a twelve-membered ring pore structure, preferably an MCM-22 molecular sieve. Further preferably, the SiO2 / Al2O3 molar ratio of the molecular sieve is 15-55, preferably 18-38.

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

[0014] In the above technical solution, preferably, in the catalyst, the metal component accounts for 0.05% to 1.0% of the mass of the molecular sieve, preferably 0.10% to 0.30% by mass.

[0015] In the above technical solution, the micropore volume of the catalyst is 0.10 to 0.30 cm 3 ·g -1, the mesopore volume is 0.30~0.65cm 3 ·g -1 , with a specific surface area of ​​300 to 650 m 2 ·g -1 Preferably, the micropore volume of the catalyst is 0.11 to 0.22 cm 3 ·g -1 , the mesopore volume is 0.40~0.65cm 3 ·g -1 , with a specific surface area of ​​350 to 500 m 2 ·g -1 .

[0016] The second aspect of the present invention provides a method for preparing the hydroalkylation catalyst, comprising: impregnating a molecular sieve with an impregnation solution containing a metal component, and then drying, calcining, ammonium exchanging, and reducing to obtain the hydroalkylation catalyst.

[0017] In the above technical solution, preferably, the method for preparing the molecular sieve comprises:

[0018] (a) contacting a silicon source, an aluminum source, an alkali source, water, a template agent, and a stabilizer to obtain a mixture A;

[0019] (b) crystallizing the mixture A to obtain the molecular sieve.

[0020] In the above technical solution, preferably, the silicon source described in step (a) is one or more of tetraethyl orthosilicate, tetraethoxysilane, alkaline silica sol, white carbon black, sodium silicate, and silicic acid.

[0021] In the above technical solution, preferably, the aluminum source described in step (a) is one or more of sodium aluminate, pseudo-boehmite, aluminum isopropoxide, aluminum sulfate, and aluminum chloride.

[0022] In the above technical solution, preferably, the alkali source in step (a) is one or more of sodium hydroxide and potassium hydroxide.

[0023] In the above technical solution, preferably, the template agent described in step (a) is one or more of hexamethyleneimine, piperidine, ethylenediamine, cyclohexylamine, and dimethylcyclohexylamine.

[0024] In the above technical solution, preferably, the stabilizer in step (a) is selected from at least one of carbonyl-nitrogen amide compounds, and the structural formula of the carbonyl-nitrogen amide compound is Wherein R1, R2 and R3 are each independently selected from a hydrogen atom or an organic group, wherein R1, R2 and R3 are each independently selected from a hydrogen atom, an ethyl group, a cyclohexyl group, a piperidinyl group, a pyridinyl group, a pyrimidinyl group, a methyl piperidinyl group, a methyl pyridinyl group or a methyl pyrimidinyl group. Further preferably, the stabilizer is selected from at least one of 4-piperidinamide, N-cyclohexylcarboxamide, N-ethylcarboxamide, 2-pyridinecarboxamide and 6-methylnicotinamide.

[0025] In the above technical scheme, preferably, in step (a), the molar ratio of the silicon source in terms of SiO2, the aluminum source in terms of Al2O3, the alkali source, water, the template and the 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).

[0026] In the above technical solution, preferably, the crystallization condition in step (b) is dynamic crystallization under closed conditions, the crystallization temperature is 90-190°C, and the crystallization time is 20-120 hours. The dynamic crystallization is carried out under stirring conditions, preferably, the stirring speed is 10-50 rpm.

[0027] In the above technical scheme, preferably, the conventional post-treatment steps in the art can be adopted after the crystallization treatment in step (b): separation, washing, drying and roasting. The separation adopts centrifugal separation, and the washing is to separate the solid obtained by deionized water washing liquid to a pH of about 7.0 to 8.0. The drying condition is drying at 100 to 180°C for 5 to 20 hours. The roasting temperature is 450 to 600°C, the roasting time is 2 to 6 hours, and the roasting atmosphere is an oxygen-containing gas, such as air.

[0028] In the above technical solution, preferably, in the method for preparing the molecular sieve, the utilization rate of the raw material aluminum source is 91.0% to 99.0%, preferably 93.0% to 98.0%.

[0029] In the above technical solution, preferably, in the catalyst preparation method, in the impregnation solution containing metal components, the metal component source can be a soluble metal salt, preferably a metal chloride.

[0030] In the above technical solution, preferably, in the catalyst preparation method, the impregnation method is preferably equal volume impregnation, the impregnation temperature is 20 to 60° C., and the impregnation time is 6 to 24 hours.

[0031] In the above technical scheme, preferably, in the catalyst preparation method, the drying conditions after impregnation are: drying temperature is 90-120°C, and drying time is 6-12h. The roasting conditions are an oxygen-containing atmosphere (such as an air atmosphere), a roasting temperature of 300-500°C, and a roasting time of 2-5h. The ammonium exchange conditions are to use an ammonium salt solution with a mass concentration of 2% to 10% at 20-70°C for 1-5h, and exchange continuously 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 is added at a liquid-to-solid volume ratio of 10:1 to 3:1.

[0032] In the above technical solution, preferably, in the catalyst preparation method, the reducing atmosphere is preferably a mixed gas of nitrogen and hydrogen, wherein the volume ratio of nitrogen to hydrogen is 9:1 to 7:3. The reducing temperature is preferably 250 to 450°C, and the time is preferably 2 to 8 hours.

[0033] In the above technical scheme, the hydroalkylation catalyst can be in any physical form, such as powder, granular or molded product, such as sheet, strip, clover. These physical forms can be obtained in any conventional manner known in the art, and there is no special limitation. When the hydroalkylation catalyst is molded as needed, the specific preparation method can be: impregnating the molecular sieve with an impregnation solution containing a metal component, then mixing and molding with a binder, and then drying, roasting, ammonium exchange, and reduction to obtain the hydroalkylation catalyst. The binder can be at least one of aluminum oxide, silicon oxide, and titanium oxide. The amount of the binder added accounts for 10% to 40% of the mass of the molecular sieve.

[0034] The catalyst of the present invention is particularly suitable for preparing cyclohexylbenzene by hydrogenation alkylation reaction of benzene.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] 1. The inventors have found through research that a hydroalkylation catalyst using a molecular sieve with a specific skeleton aluminum content and distribution as a carrier and an alkylation active component and a noble metal as a hydrogenation active component, when used in a benzene hydroalkylation reaction, can improve the benzene conversion rate and the selectivity of the cyclohexylbenzene product under relatively low metal loading and relatively mild reaction conditions, and has good stability.

[0037] 2. The present invention effectively limits and regulates the distribution of framework aluminum in the molecular sieve by introducing a stabilizer during the preparation process of the molecular sieve. After the metal is loaded, efficient coordination between the metal active center and the molecular sieve alkylation center can be achieved, thereby jointly improving the performance of the catalyst, especially for benzene hydroalkylation reaction, with good cyclohexylbenzene selectivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The XRD spectra of the molecular sieves obtained in Example 1 and Comparative Example 1 of the present invention are shown in FIG.

[0039] Figure 2 This is the Al-NMR spectrum of the molecular sieve obtained in Example 1 of the present invention;

[0040] Figure 3 This is the Al-NMR spectrum of the molecular sieve obtained in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0041] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the present invention is described in detail below in conjunction with specific implementation methods, but it should be understood that the protection scope of the present invention is not limited to the specific implementation methods.

[0042] In the present invention, the distribution of aluminum species in the molecular sieve is determined by analyzing 27 The Al MAS NMR test results were obtained. The test was carried out on a JEOL 500MHz (11.7T) spectrometer using a 3.2mm HX MAS NMR probe at a rotation speed of 18kHz. The spectrum was acquired at a resonance frequency of 130.3MHz. The chemical shift was referenced to a 1mol / L Al(NO3)3 solution (δ=0ppm). The δ=0ppm and 54ppm in the spectrum corresponded to the octahedral coordinated non-framework aluminum (Al [EF] ) and tetracoordinated framework aluminum (Al [F] ) characteristic peaks, and the latter peak fitting calculation can determine the distribution of aluminum on different tetrahedral sites, where the Al location at δ = 50ppm (Al (50) ) corresponds to the Al of molecular sieve 12MR super cage F Distribution, Al location at δ = 56 ppm (Al (56) ) corresponds to Al in the sinusoidal channel [F] Distribution, Al location at δ = 61ppm (Al (61) ) corresponds to the Al on the outer surface of the 12MR half-supercage [F] distributed.

[0043] In the present invention, a Micromeritics ASAP-2000 physical adsorption instrument is used to measure the N2 adsorption-desorption isotherm at 77K. The sample is degassed and vacuum treated at 573K for 4 hours before testing. The total pore volume and specific surface area are calculated using the BET equation, and the micropore volume is determined using the t-plot curve method. The difference between the total pore volume and the micropore volume is the mesopore volume.

[0044] In the present invention, the SiO2 / Al2O3 molar ratio of the molecular sieve and the utilization rate of the raw aluminum source are obtained by ICP testing and calculation, and are measured using a Varian 725-ES ICP-AES analyzer.

[0045] [Example 1]

[0046] This example is used to synthesize a hydroalkylation catalyst, and the specific preparation process is as follows:

[0047] (1) Dissolve 11.3 g of sodium aluminate (Al2O3 45.0 wt%) and 6.0 g of sodium hydroxide in 234.0 g of water, continue stirring until dissolved, add 24.8 g of hexamethyleneimine and 6.4 g of 4-piperidinecarboxamide, stir for 30 min, and then add 208.3 g of tetraethoxysilane. The molar ratio of the reactants is tetraethoxysilane calculated as SiO2: sodium aluminate calculated as Al2O3: NaOH: water: hexamethyleneimine: stabilizer = 1: 0.05: 0.15: 13: 0.25: 0.05. Continue stirring for 30 minutes until the mixture is evenly mixed, then put it into a stainless steel reactor with a polytetrafluoroethylene liner, and place it in a homogeneous reactor for crystallization at 160°C and 30 rpm for 72 hours. Then, centrifuge the resulting mixture, wash it with deionized water to a pH of 7, and then place it in a 150°C oven to dry for 8 hours, and place it in an air atmosphere at 500°C for calcination for 5 hours to obtain molecular sieve M1.

[0048] (2) Take 1.0 g of the M1 molecular sieve obtained in step (1), and continuously drip deionized water until the molecular sieve is just saturated and wet. The corresponding water absorption of 1.0 g of the molecular sieve is calculated to be 1.7 mL; 17 mL of a 1.2 mg / mL RuCl3 aqueous solution is added dropwise to 10 g of the molecular sieve obtained in step (1), and an oscillator is used during the process to evenly distribute the metal salt solution on the molecular sieve. After standing at 30°C for 12 hours, 3.0 g of alumina is added and mixed, kneaded into strips, and dried at a constant temperature of 120°C for 12 hours, and then calcined in an air atmosphere at 350°C for 3 hours; according to a liquid-to-solid volume ratio of 10:1, an ammonium acetate solution with a mass concentration of 5% is used for treatment at 30°C for 2 hours, and the mixture is exchanged continuously for 3 times; then placed in a tubular furnace, a mixed gas of nitrogen and hydrogen with a volume ratio of 9:1 is introduced, and the target catalyst C1 is obtained after reduction at 300°C for 2 hours. In the catalyst, Ru accounts for 0.2% of the mass of the molecular sieve.

[0049] The XRD spectrum of the obtained M1 molecular sieve is as follows: Figure 1 shown.

[0050] The Al-NMR spectrum of the obtained M1 molecular sieve is as follows: Figure 2 The distribution of aluminum species is shown in Table 1.

[0051] The utilization rate of the raw material aluminum source when preparing molecular sieve M1 is shown in Table 1.

[0052] Through testing, the micropore volume of catalyst C1 is 0.15cm 3 ·g -1 The mesopore volume is 0.59 cm 3 ·g -1 , with a specific surface area of ​​427m 2 ·g -1 .

[0053] Catalyst C1 was evaluated for hydroalkylation reaction at a reaction temperature of 140 °C, a reaction pressure of 0.9 MPa, and a mass space velocity of benzene of 1 h -1 The molar ratio of hydrogen to benzene was 0.5. The results after 36 hours of reaction are shown in Table 2.

[0054] [Example 2]

[0055] This example is used to synthesize a hydroalkylation catalyst, and the specific preparation process is as follows:

[0056] (1) 9.2 g of sodium aluminate (Al2O3 45.0 wt%) and 2.0 g of sodium hydroxide were dissolved in 360.0 g of water. After continuous stirring until dissolved, 70.1 g of hexamethyleneimine and 9.8 g of 2-pyridinecarboxamide were added. After stirring for 30 min, 208.3 g of tetraethoxysilane was added. The molar ratio of the reactants was tetraethoxysilane calculated as SiO2: sodium aluminate calculated as Al2O3: NaOH: water: hexamethyleneimine: stabilizer = 1: 0.04: 0.05: 20: 0.5: 0.08. Continue stirring for 30 minutes until the mixture is evenly mixed, put it into a stainless steel reactor with a polytetrafluoroethylene liner, place it in a homogeneous reactor and crystallize it at 170°C and 20rpm for 60 hours. Then, centrifuge the resulting mixture and wash it with deionized water to a pH of 7, then place it in a 130°C oven to dry for 10 hours, and place it in an air atmosphere at 550°C for 4 hours to obtain molecular sieve M2.

[0057] (2) Take 1.0 g of the M2 molecular sieve obtained in step (1), and continuously drip deionized water until the molecular sieve is just saturated and wet. The corresponding water absorption of 1.0 g of the molecular sieve is calculated to be 1.7 mL; 17 mL of a 1.5 mg / mL PdCl2 aqueous solution is added dropwise to 10 g of the molecular sieve obtained in step (1), and an oscillator is used during the process to evenly distribute the metal salt solution on the molecular sieve. After standing at 20°C for 16 hours, 2.5 g of alumina is added and mixed, and kneaded into a clover shape, and dried at a constant temperature of 110°C for 10 hours, and then calcined in an air atmosphere at 300°C for 4 hours; according to a liquid-to-solid volume ratio of 8:1, an ammonium sulfate solution with a mass concentration of 7% is used for treatment at 20°C for 1 hour, and the mixture is exchanged continuously for 4 times; then placed in a tubular furnace, a mixed gas with a volume ratio of nitrogen and hydrogen of 7:1 is introduced, and the target catalyst C2 is obtained after reduction at 280°C for 3 hours. In the catalyst, Pd accounts for 0.25% of the mass of the molecular sieve.

[0058] From the XRD spectrum of molecular sieve M2, it can be known that it is MCM-22 molecular sieve.

[0059] The Al-NMR test on molecular sieve M2 and the distribution of aluminum species obtained by peak fitting are shown in Table 1.

[0060] The utilization rate of the raw material aluminum source when preparing molecular sieve M2 is shown in Table 1.

[0061] Through testing, the micropore volume of catalyst C2 is 0.13 cm 3 ·g -1 , the mesopore volume is 0.51cm 3 ·g -1 , with a specific surface area of ​​410m 2 ·g -1 .

[0062] Catalyst C2 was evaluated for hydroalkylation reaction at a reaction temperature of 140°C, a reaction pressure of 0.9 MPa, and a mass space velocity of benzene of 1 h -1 The molar ratio of hydrogen to benzene was 0.5. The results after 36 hours of reaction are shown in Table 2.

[0063] [Example 3]

[0064] This example is used to synthesize a hydroalkylation catalyst, and the specific preparation process is as follows:

[0065] (1) 6.8 g of sodium aluminate (Al2O3 45.0 wt%) and 8.0 g of sodium hydroxide were dissolved in 270.0 g of water, and 17.0 g of piperidine and 4.1 g of 6-methylnicotinamide were added after continuous stirring until dissolved. After stirring for 30 min, 208.3 g of tetraethoxysilane was added. The molar ratio of the reactants was tetraethoxysilane in terms of SiO2: sodium aluminate in terms of Al2O3: NaOH: water: piperidine: stabilizer = 1: 0.03: 0.2: 15: 0.2: 0.03. Stirring was continued for 30 min until the mixture was uniformly mixed, and then the mixture was placed in a stainless steel reactor with a polytetrafluoroethylene liner, and placed in a homogeneous reactor for crystallization at 150° C. and 25 rpm for 96 hours. The obtained mixture was then centrifuged and washed with deionized water until the pH was 7, and then placed in a 140° C. oven for drying for 9 hours, and then placed in an air atmosphere for calcination at 550° C. for 6 hours to obtain molecular sieve M3.

[0066] (2) Take 1.0 g of the M3 molecular sieve obtained in step (1), continuously drip deionized water until the molecular sieve is just saturated and wet, calculate that the corresponding water absorption of 1.0 g of the molecular sieve is 1.7 mL, add 17 mL of 0.6 mg / mL PtCl4 aqueous solution dropwise to 10 g of the molecular sieve obtained in step (1), during which the metal salt solution is evenly distributed on the molecular sieve with an oscillator, stand at 40°C for 10 h, add 3.5 g of alumina to mix, knead and shape into strips, dry at 100°C for 10 h, and then roast in an air atmosphere at 400°C for 2 h; treat with an ammonium acetate solution with a mass concentration of 8% at 40°C for 1 h according to a liquid-to-solid volume ratio of 6:1, and exchange continuously for 4 times; then place in a tubular furnace, pass a mixed gas of nitrogen and hydrogen with a volume ratio of 8:1, and reduce at 300°C for 3 h to obtain the target catalyst C3. In the catalyst, Pt accounts for 0.1% of the mass of the molecular sieve.

[0067] From the XRD spectrum of molecular sieve M3, it can be known that it is MCM-22 molecular sieve.

[0068] The Al-NMR test on molecular sieve M3 and the distribution of aluminum species obtained by peak fitting are shown in Table 1.

[0069] The utilization rate of the raw material aluminum source when preparing molecular sieve M3 is shown in Table 1.

[0070] Through testing, the micropore volume of catalyst C3 is 0.12cm 3 ·g -1 , the mesopore volume is 0.47 cm 3 ·g -1 , with a specific surface area of ​​392m 2 ·g -1 .

[0071] Catalyst C3 was evaluated for hydroalkylation reaction at a reaction temperature of 140°C, a reaction pressure of 0.9 MPa, and a mass space velocity of benzene of 1 h -1 The molar ratio of hydrogen to benzene was 0.5. The results after 36 hours of reaction are shown in Table 2.

[0072] [Example 4]

[0073] This example is used to synthesize a hydroalkylation catalyst, and the specific preparation process is as follows:

[0074] (1) Dissolve 5.8 g of pseudo-boehmite and 8.4 g of potassium hydroxide in 216.0 g of water, continue stirring until dissolved, then add 24.8 g of hexamethyleneimine and 3.7 g of N-ethylformamide, stir for 30 min, and then add 150.0 g of silica sol. The molar ratio of the reactants is silica sol in terms of SiO2: pseudo-boehmite in terms of Al2O3: KOH: water: hexamethyleneimine: stabilizer = 1: 0.05: 0.15: 12: 0.25: 0.05. Continue stirring for 30 min until the mixture is uniformly mixed, then put it into a stainless steel reactor with a polytetrafluoroethylene liner, place it in a homogeneous reactor at 175°C and 15 rpm for crystallization for 40 hours, then centrifuge the resulting mixture, wash it with deionized water to a pH of 7, place it in a 120°C oven for drying for 12 hours, and place it in an air atmosphere for calcination at 480°C for 5 hours to obtain M4 molecular sieve.

[0075] (2) 1.0 g of the M4 molecular sieve obtained in step (1) was taken, and deionized water was continuously added until the molecular sieve was just saturated and wetted. The corresponding water absorption of 1.0 g of the molecular sieve was calculated to be 1.7 mL. 17 mL of a 0.9 mg / mL RuCl3 aqueous solution was added dropwise to 10 g of the molecular sieve obtained in step (1). During this period, an oscillator was used to evenly distribute the metal salt solution on the molecular sieve. After standing at 30° C. for 10 h, 2.5 g of alumina was added and mixed. The mixture was kneaded into strips, dried at a constant temperature of 120° C. for 8 h, and then calcined in an air atmosphere at 450° C. for 2 h; at a liquid-to-solid volume ratio of 5:1, an ammonium acetate solution with a mass concentration of 9% was used for treatment at 30° C. for 1 h, and the treatment was repeated 4 times; then the mixture was placed in a tubular furnace, and a mixed gas with a volume ratio of nitrogen and hydrogen of 6:1 was introduced, and the target catalyst C4 was obtained after reduction at 350° C. for 2 h. In the catalyst, Ru accounts for 0.15% of the mass of the molecular sieve.

[0076] From the XRD spectrum of molecular sieve M4, it can be known that it is MCM-22 molecular sieve.

[0077] The Al-NMR test on molecular sieve M4 and the distribution of aluminum species obtained by peak fitting are shown in Table 1.

[0078] The utilization rate of the raw material aluminum source when preparing molecular sieve M4 is shown in Table 1.

[0079] Through testing, the micropore volume of catalyst C4 is 0.13cm 3 ·g -1 , the mesopore volume is 0.48 cm 3 ·g -1 , with a specific surface area of ​​404m 2 ·g -1 .

[0080] Catalyst C4 was evaluated for hydroalkylation reaction at a reaction temperature of 140°C, a reaction pressure of 0.9 MPa, and a mass space velocity of benzene of 1 h -1 The molar ratio of hydrogen to benzene was 0.5. The results after 36 hours of reaction are shown in Table 2.

[0081] [Example 5]

[0082] This example is used to synthesize a hydroalkylation catalyst, and the specific preparation process is as follows:

[0083] (1) Dissolve 10.2g of aluminum isopropoxide and 6.0g of NaOH in 324.0g of water, continue stirring until dissolved, add 24.8g of hexamethyleneimine and 6.4g of N-cyclohexylformamide, stir for 30min, and then add 65.0g of white carbon black. The molar ratio of the reactants is white carbon black in terms of SiO2: aluminum isopropoxide in terms of Al2O3: NaOH: water: hexamethyleneimine: stabilizer = 1: 0.05: 0.2: 18: 0.25: 0.05. Continue stirring for 30min until the mixture is uniformly mixed, then put it into a stainless steel reactor with a polytetrafluoroethylene liner, place it in a homogeneous reactor at 160°C and 30rpm for crystallization for 72 hours, then centrifuge the obtained mixture, wash it with deionized water to pH 7, and then place it in a 150°C oven for drying for 8h, and place it in an air atmosphere for calcination at 500°C for 5h to obtain M5 molecular sieve.

[0084] (2) Take 1.0 g of the M5 molecular sieve obtained in step (1), and continuously drip deionized water until the molecular sieve is just saturated and wet. The corresponding water absorption of 1.0 g of the molecular sieve is calculated to be 1.7 mL. 17 mL of a 1.2 mg / mL RuCl3 aqueous solution is dropwise added to 10 g of the molecular sieve obtained in step (1). During this period, an oscillator is used to evenly distribute the metal salt solution on the molecular sieve. After standing at 30°C for 12 hours, 2 g of silicon oxide is added and mixed. The mixture is kneaded into strips, dried at a constant temperature of 120°C for 12 hours, and then calcined in an air atmosphere at 350°C for 3 hours; according to a liquid-to-solid volume ratio of 10:1, an ammonium acetate solution with a mass concentration of 5% is used for treatment at 30°C for 2 hours, and the mixture is exchanged continuously for 3 times; then the mixture is placed in a tubular furnace, and a mixed gas with a volume ratio of nitrogen and hydrogen of 9:1 is introduced. After 2 hours at 300°C, the target catalyst C5 is obtained. In the catalyst, Ru accounts for 0.2% of the mass of the molecular sieve.

[0085] From the XRD spectrum of molecular sieve M5, it can be known that it is MCM-22 molecular sieve.

[0086] The Al-NMR test of molecular sieve M5 and the distribution of aluminum species obtained by peak fitting are shown in Table 1.

[0087] The utilization rate of the raw material aluminum source when preparing molecular sieve M5 is shown in Table 1.

[0088] Through testing, the micropore volume of catalyst C5 is 0.14 cm 3 ·g -1 , the mesopore volume is 0.50cm 3 ·g -1 , with a specific surface area of ​​415m 2 ·g -1 .

[0089] Catalyst C5 was evaluated for hydroalkylation reaction at a reaction temperature of 140°C, a reaction pressure of 0.9 MPa, and a mass space velocity of benzene of 1 h -1 The molar ratio of hydrogen to benzene was 0.5. The results after 36 hours of reaction are shown in Table 2.

[0090] [Example 6]

[0091] This example is used to synthesize a hydroalkylation catalyst, and the specific preparation process is as follows:

[0092] (1) Dissolve 11.3 g of sodium aluminate (Al2O3 45.0 wt%) and 6.0 g of sodium hydroxide in 234.0 g of water, continue stirring until dissolved, add 24.8 g of hexamethyleneimine and 6.4 g of 4-piperidinecarboxamide, stir for 30 min, and then add 208.3 g of tetraethoxysilane. The molar ratio of the reactants is tetraethoxysilane calculated as SiO2: sodium aluminate calculated as Al2O3: NaOH: water: hexamethyleneimine: stabilizer = 1: 0.05: 0.15: 13: 0.25: 0.05. Continue stirring for 30 minutes until the mixture is evenly mixed, then put it into a stainless steel reactor with a polytetrafluoroethylene liner, and place it in a homogeneous reactor for crystallization at 160°C and 30 rpm for 72 hours. Then, centrifuge the resulting mixture, wash it with deionized water to a pH of 7, and then place it in a 150°C oven to dry for 8 hours, and place it in an air atmosphere at 500°C for 5 hours to obtain molecular sieve M6.

[0093] (2) Take 1.0 g of the M6 ​​molecular sieve obtained in step (1), continuously drip deionized water until the molecular sieve is just saturated and wet, calculate that the corresponding water absorption of 1.0 g of the molecular sieve is 1.7 mL, add 17 mL of 1.2 mg / mL RuCl3 aqueous solution dropwise to 10 g of the molecular sieve obtained in step (1), during which the metal salt solution is evenly distributed on the molecular sieve with an oscillator, and after standing for 12 hours, add 3 g of titanium oxide and mix, knead and shape into strips, dry at a constant temperature of 120° C. for 12 hours, and then roast in an air atmosphere at 350° C. for 3 hours; according to the liquid-to-solid volume ratio of 10:1, use a 5% ammonium acetate solution at 30° C. for 2 hours, and exchange continuously for 3 times; then place it in a tubular furnace, pass a mixed gas of nitrogen and hydrogen in a volume ratio of 9:1, heat it to 300° C. at a heating rate of 2° C. / min, and reduce it for 2 hours to obtain the target catalyst C6. In the catalyst, Ru accounts for 0.25% of the mass of the molecular sieve.

[0094] The XRD spectrum of molecular sieve M6 shows that it is MCM-22 molecular sieve. The Al-NMR test of molecular sieve M6 and the distribution of aluminum species obtained by peak fitting are shown in Table 1.

[0095] The utilization rate of the raw material aluminum source when preparing molecular sieve M6 is shown in Table 1.

[0096] Through testing, the micropore volume of catalyst C6 is 0.15cm 3 ·g -1 The mesopore volume is 0.49 cm 3 ·g -1 , with a specific surface area of ​​418m 2 ·g -1 .

[0097] Catalyst C6 was evaluated for hydroalkylation reaction at a reaction temperature of 140°C, a reaction pressure of 0.9 MPa, and a mass space velocity of benzene of 1 h -1 The molar ratio of hydrogen to benzene was 0.5. The results after 36 hours of reaction are shown in Table 2.

[0098] [Comparative Example 1]

[0099] Compared with Example 1, no stabilizer was added in this comparative example, and the other steps were the same. The specific process is as follows:

[0100] (1) Dissolve 11.3g sodium aluminate (Al2O3 45.0wt%) and 6.0g sodium hydroxide in 234.0g water, continue stirring until dissolved, add 24.8g hexamethyleneimine, stir for 30min, add 208.3g tetraethoxysilane, the material molar ratio of the reactants is tetraethoxysilane in terms of SiO2: sodium aluminate in terms of Al2O3: NaOH: water: hexamethyleneimine = 1: 0.05: 0.15: 13: 0.25. Continue stirring for 30min until the mixture is uniformly mixed, put it into a stainless steel reactor with a polytetrafluoroethylene liner, place it in a homogeneous reactor at 160°C and 30rpm for crystallization for 72 hours, then centrifuge the obtained mixture, wash it with deionized water to pH 7, place it in a 150°C oven for drying for 8h, place it in an air atmosphere for calcination at 500°C for 5h, and obtain D1 molecular sieve for standby use.

[0101] (2) Take 1 g of the D1 molecular sieve obtained in step (1), continuously drip deionized water until the molecular sieve is just saturated and wet, calculate that the corresponding water absorption of 1 g of the molecular sieve is 1.7 mL, add 17 mL of 1.2 mg / mL RuCl3 aqueous solution dropwise to 10 g of the molecular sieve obtained in step (1), during which the metal salt solution is evenly distributed on the molecular sieve with an oscillator, stand at 30°C for 12 hours, add 3 g of alumina and mix, knead and shape into strips, dry at 120°C for 12 hours, and then calcine in an air atmosphere at 350°C for 3 hours; treat with 5% ammonium acetate solution at 30°C for 2 hours at a liquid-to-solid volume ratio of 10:1, and exchange continuously for 3 times; then place in a tubular furnace, pass a mixed gas of nitrogen and hydrogen in a volume ratio of 9:1, heat to 300°C at a rate of 2°C / min, and reduce for 2 hours to obtain the target catalyst C7. In the catalyst, Ru accounts for 0.2% of the mass of the molecular sieve.

[0102] The XRD spectrum of the obtained D1 molecular sieve is as follows: Figure 1 shown.

[0103] The Al-NMR spectrum of the obtained D1 molecular sieve is as follows: Figure 3 The distribution of aluminum species obtained by peak fitting is shown in Table 1.

[0104] The utilization rate of the raw material aluminum source when preparing molecular sieve D1 is shown in Table 1.

[0105] Through testing, the micropore volume of catalyst C7 is 0.12cm 3 ·g -1 , the mesopore volume is 0.46 cm 3 ·g -1 , with a specific surface area of ​​389m 2 ·g -1 .

[0106] Catalyst C7 was evaluated for hydroalkylation reaction at a reaction temperature of 140°C, a reaction pressure of 0.9 MPa, and a mass space velocity of benzene of 1 h -1 The molar ratio of hydrogen to benzene was 0.5. The results after 36 hours of reaction are shown in Table 2.

[0107] [Comparative Example 2]

[0108] Compared with Example 1, this comparative example does not load metal, and the other steps are the same. The specific process is as follows:

[0109] (1) Dissolve 11.3 g of sodium aluminate (Al2O3 45.0 wt%) and 6.0 g of sodium hydroxide in 234.0 g of water, continue stirring until dissolved, add 24.8 g of hexamethyleneimine and 6.4 g of 4-piperidinecarboxamide, stir for 30 min, and then add 208.3 g of tetraethoxysilane. The molar ratio of the reactants is tetraethoxysilane calculated as SiO2: sodium aluminate calculated as Al2O3: NaOH: water: hexamethyleneimine: stabilizer = 1: 0.05: 0.15: 13: 0.25: 0.05. Continue stirring for 30 minutes until the mixture is evenly mixed, then put it into a stainless steel reactor with a polytetrafluoroethylene liner, place it in a homogeneous reactor and crystallize it at 160°C and 30 rpm for 72 hours. Then, centrifuge the resulting mixture, wash it with deionized water to a pH of 7, place it in a 150°C oven to dry for 8 hours, and place it in an air atmosphere at 500°C for 5 hours to obtain a D2 molecular sieve.

[0110] (2) Take 10g of molecular sieve and add 3.0g of alumina to mix, knead and shape into strips, dry at a constant temperature of 120°C for 12h, and then calcine in an air atmosphere at 350°C for 3h; treat with a 5% ammonium acetate solution at a liquid-to-solid volume ratio of 10:1 at 30°C for 2h, and exchange three times continuously; then place in a tubular furnace, pass a mixed gas of nitrogen and hydrogen in a volume ratio of 9:1, and reduce at 300°C for 2h to obtain the target catalyst C8.

[0111] Through testing, the micropore volume of catalyst C8 is 0.16cm 3 ·g -1 , the mesopore volume is 0.60cm 3 ·g -1 , with a specific surface area of ​​440m 2 ·g -1 .

[0112] Catalyst C8 was evaluated for hydroalkylation reaction at a reaction temperature of 140°C, a reaction pressure of 0.9 MPa, and a mass space velocity of benzene of 1 h -1 The molar ratio of hydrogen to benzene was 0.5. The results after 36 hours of reaction are shown in Table 2.

[0113] Table 1 Distribution of aluminum species in the molecular sieves obtained in each case, silicon-aluminum ratio and utilization rate of raw aluminum source in molecular sieve preparation

[0114]

[0115] Table 2 Reaction results of the catalysts obtained in each example applied to benzene hydroalkylation to produce cyclohexylbenzene

[0116]

[0117]

[0118] One-way life test

[0119] Catalysts C1-C7 prepared in Examples 1-6 and Comparative Example 1 were tested for their one-way life in benzene hydroalkylation reaction under ultra-high benzene space velocity reaction conditions, with a reaction temperature of 140°C, a reaction pressure of 0.9 MPa, and a mass space velocity of benzene of 8 h -1 , the molar ratio of hydrogen to benzene is 0.5, and the one-way life refers to the time from the start of the reaction to the time when the conversion rate of benzene drops to 40% of the initial conversion rate. The test results are shown in Table 3.

[0120] Table 3

[0121] Catalyst No. One-way life, h C1 167 C2 151 C3 142 C4 158 C5 149 C6 150 C7 85

[0122] The embodiments of the present invention are only 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 can be implemented without relying on the steps described in the above embodiments. In summary, any improvements made by those skilled in the art to the present invention, including replacement of the raw materials and additives described in the present invention, selection of specific implementation methods, etc., all belong to the protection scope and disclosure scope of the present invention.

Claims

1. A hydroalkylation catalyst comprising a metal component and a molecular sieve, wherein the framework aluminum (Al [F] ) and non-framework aluminum (Al [EF] ) is 5.0 to 15.0:1, preferably 7.0 to 11.0:1, and more preferably 7.0 to 10.0:

1.

2. The catalyst according to claim 1, characterized in that The outer surface of the molecular sieve is semi-super cage aluminum (Al (61) ) and skeleton aluminum (Al [F] ) weight ratio is 0.22 to 0.50:1, preferably 0.22 to 0.42:1, and more preferably 0.25 to 0.30:

1.

3. The catalyst according to claim 1, characterized in that The molecular sieve is a silicon-aluminum molecular sieve having a twelve-membered ring pore structure, preferably a MCM-22 molecular sieve.

4. The catalyst according to claim 1, characterized in that In the catalyst, the metal component is selected from at least one of Ru, Pd and Pt. Preferably, in the catalyst, the metal component accounts for 0.05% to 1.0% of the mass of the molecular sieve, preferably 0.10% to 0.30% by mass.

5. The catalyst according to claim 1, characterized in that The micropore volume of the catalyst is 0.10 to 0.30 cm 3 ·g -1 , the mesopore volume is 0.30~0.65cm 3 ·g -1 , with a specific surface area of ​​300 to 650 m 2 ·g -1 Preferably, the micropore volume of the catalyst is 0.11 to 0.22 cm 3 ·g -1 , the mesopore volume is 0.40~0.65cm 3 ·g -1 , with a specific surface area of ​​350 to 500 m 2 ·g -1 .

6. The method for preparing the hydroalkylation catalyst according to any one of claims 1 to 5, comprising: The molecular sieve is impregnated with an impregnation solution containing metal components, and then dried, calcined, ammonium exchanged and reduced to obtain the hydroalkylation catalyst.

7. The preparation method according to claim 6, characterized in that: The preparation method of the molecular sieve comprises: (a) contacting a silicon source, an aluminum source, an alkali source, water, a template agent, and a stabilizer to obtain a mixture A; (b) crystallizing the mixture A to obtain the molecular sieve.

8. The preparation method according to claim 7, characterized in that: The silicon source described in step (a) is one or more of tetraethyl orthosilicate, tetraethoxysilane, alkaline silica sol, white carbon, sodium silicate, and silicic acid; and / or, the aluminum source is one or more of sodium aluminate, pseudo-boehmite, aluminum isopropoxide, aluminum sulfate, and aluminum chloride; and / or, the alkali source is one or more of sodium hydroxide and potassium hydroxide; and / or, the template is one or more of hexamethyleneimine, piperidine, ethylenediamine, cyclohexylamine, and dimethylcyclohexylamine.

9. The preparation method according to claim 7, characterized in that: The stabilizer in step (a) is selected from at least one of carbonyl-nitrogen amide compounds, the structural formula of which is Wherein R1, R2 and R3 are each independently selected from a hydrogen atom or an organic group; preferably, R1, R2 and R3 are each independently selected from a hydrogen atom, an ethyl group, a cyclohexyl group, a piperidinyl group, a pyridinyl group, a pyrimidinyl group, a methyl piperidinyl group, a methyl pyridinyl group or a methyl pyrimidinyl group; further preferably, the stabilizer is selected from at least one of 4-piperidinamide, N-cyclohexylcarboxamide, N-ethylcarboxamide, 2-pyridinecarboxamide and 6-methylnicotinamide.

10. The preparation method according to claim 7, characterized in that: In step (a), the molar ratio of the silicon source in terms of SiO2, the aluminum source in terms of Al2O3, the alkali source, water, the template and the 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).

11. The preparation method according to claim 7, characterized in that: The crystallization conditions in step (b) are dynamic crystallization under closed conditions, the crystallization temperature is 90 to 190° C., and the crystallization time is 20 to 120 hours.

12. The preparation method according to claim 7, characterized in that: In the method for preparing the molecular sieve, the utilization rate of the raw material aluminum source is 91.0% to 99.0%, preferably 93.0% to 98.0%.

13. The preparation method according to claim 6, characterized in that: In the catalyst preparation method, the impregnation method is equal volume impregnation, the impregnation temperature is 20-60°C, and the impregnation time is 6-24 hours; and / or, the drying temperature is 90-120°C, and the drying time is 6-12 hours; and / or, the roasting condition is an oxygen-containing atmosphere, the roasting temperature is 300-500°C, and the roasting time is 2-5 hours; and / or, the ammonium exchange condition is using an ammonium salt solution with a mass concentration of 2% to 10% at 20-70°C for 1-5 hours, and continuously exchanging 2-5 times; and / or, the reducing atmosphere is a mixed gas of nitrogen and hydrogen, wherein the volume ratio of nitrogen to hydrogen is 9:1-7:3, the reduction temperature is preferably 250-450°C, and the time is preferably 2-8 hours.

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