A catalyst for producing cyclohexylbenzene, a method for preparing the same, and an application thereof

Abstract

The application discloses a catalyst for producing cyclohexylbenzene and a preparation method and application thereof. The catalyst comprises a molecular sieve, an active metal M and an R group; wherein the active metal M is selected from one or more of ruthenium, platinum, palladium, copper and nickel; wherein the R group is selected from at least one of C1-C4 alkyl; wherein the mass content of the active metal M is 0.2% to 1.5% based on the mass of the catalyst; the mass content of the metal M on the outer surface of the catalyst accounts for 0.4% or less of the mass of the outer surface elements; and the content of the outer surface metal M accounts for 1.2% to 20% of the total metal M content in the catalyst. When the catalyst is used in the production of cyclohexylbenzene by benzene hydrogenation alkylation, the product has the characteristics of good selectivity and less by-product cyclohexane.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chemical technology, in particular to a catalyst for producing cyclohexylbenzene and a preparation method and application thereof. BACKGROUND

[0002] Cyclohexylbenzene is an important chemical product, which has important applications in the fields of liquid crystal and rechargeable batteries. Cyclohexylbenzene liquid crystal has extremely high chemical stability, photochemical stability and excellent physical properties, and is one of the ideal materials for liquid crystal displays. Cyclohexylbenzene can also be used as an additive component in the electrolyte of lithium ion batteries, which can effectively improve the safety of the battery due to its overcharge prevention function. In addition, cyclohexylbenzene can be used as an intermediate to prepare important chemical products such as phenol and cyclohexanone through further peroxidation and decomposition reactions, which can be used in the production of phenolic resin, caprolactam and nylon. Therefore, the preparation and production of cyclohexylbenzene have attracted widespread attention. The basic information of cyclohexylbenzene is as follows: colorless liquid, CAS number 827-52-1, density 0.95 g / cm 3 , boiling point 238-240℃, melting point 5℃, flash point 98℃.

[0003] According to different raw materials, the main methods for preparing cyclohexylbenzene include hexene alkylation method and benzene hydrogenation alkylation method. The basic principle of benzene hydrogenation alkylation method is to use benzene and hydrogen as raw materials, and to obtain a 6-membered ring olefin structure (such as cyclohexene) by hydrogenation of part of benzene on a metal active center. Further alkylation reaction with benzene on the acid active center position to obtain cyclohexylbenzene product. Therefore, a bifunctional catalyst with hydrogenation center and alkylation active center can be used for the production process of cyclohexylbenzene.

[0004] The research on the preparation of cyclohexylbenzene by benzene hydrogenation alkylation method was first started in the 1980s. The catalysts developed at present are mainly metal supported on molecular sieves, most of which have the problems of slow catalytic efficiency and low selectivity. For example, the catalyst based on MCM-22 series molecular sieves (US2011 / 0015457A1, CN104105679A) has the problems of slow catalytic rate and high selectivity of by-product cyclohexane. Other catalysts such as Ni-rare earth treated HY molecular sieve as carrier (US4219689) have the problems of low benzene conversion rate and low yield of cyclohexylbenzene product. Subsequently, it was reported (Molecular Catalysis 2017, 442, 27-38) that Pd / HY supported molecular sieve was used as catalyst for one-step catalytic benzene hydrogenation alkylation to prepare cyclohexylbenzene. The initial conversion rate of benzene was 42.2%, the selectivity of cyclohexylbenzene was maintained at about 75%, and the selectivity of excessive hydrogenation by-product cyclohexane was as high as about 20%.

[0005] In summary, the prior art mainly has the problems of poor product selectivity and more by-product cyclohexane, which brings great problems to industrial practical application. SUMMARY

[0006] The present application provides a catalyst for producing cyclohexylbenzene and a preparation method and application thereof. The catalyst provided by the present application has the characteristics of good product selectivity and less by-product cyclohexane in the production of cyclohexylbenzene by benzene hydrogenation alkylation.

[0007] The present application provides a catalyst for producing cyclohexylbenzene, which comprises a molecular sieve, an active metal M and an R group.

[0008] The active metal M is selected from one or more of ruthenium, platinum, palladium, copper and nickel.

[0009] The R group is selected from at least one of C1-C4 alkyl groups.

[0010] The mass content of the active metal M in the catalyst is 0.2% to 1.5%, the mass content of the metal M on the outer surface of the catalyst is 0.4% or less, and the metal M on the outer surface accounts for 1.2% to 20% of the total content of the metal M in the catalyst.

[0011] Further, the M is preferably a ruthenium metal element.

[0012] Further, the mass content of the M in the catalyst is preferably 0.2% to 1.2%, more preferably 0.3% to 1.0%, for example but not limited to 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% and the like.

[0013] Further, the R group in the catalyst is preferably selected from at least one of methyl, ethyl, propyl and isopropyl.

[0014] Further, the mass content of the R group in the catalyst is 1% to 10% based on the mass of the catalyst.

[0015] Further, the M in the catalyst exists in at least one of the forms of an element, an oxide, a chloride and a nitrate.

[0016] Further, the mass content of the metal M on the outer surface of the catalyst is 0.01% to 0.35% of the mass of the outer surface elements, and the metal M on the outer surface accounts for 1.5% to 18% of the total content of the metal M in the catalyst.

[0017] Further, in the catalyst, the molecular sieve is selected from at least one of MWW, FAU, MOR, BEA, and ATS.

[0018] Further, in the catalyst, the molecular sieve accounts for 90% to 98% of the mass of the catalyst, and the molar ratio of silicon to aluminum is 2 to 50, preferably 4 to 40.

[0019] Further, the specific surface area of the catalyst is 380 to 800 m 2 / g, preferably 400 to 700 m 2 / g, and more preferably 440 to 700 m 2 / g; and the total pore volume of the catalyst is not less than 0.15 cm 3 / g, and preferably 0.2 to 0.9 cm 3 / g.

[0020] Further, the total acid amount of the catalyst is 400 to 1500 μmol·g -1 , and preferably 450 to 1250 μmol·g -1 .

[0021] Further, the relative acid equivalent of the external surface of the catalyst is 30% to 50%.

[0022] Further, the ratio of the acid amount of B acid to L acid of the catalyst is 0.2 to 6.0, and preferably 0.4 to 5.5.

[0023] The second aspect of the present application provides a preparation method of the catalyst for producing cyclohexylbenzene described above, comprising the following steps:

[0024] (1) subjecting a molecular sieve I to ammonium ion exchange and calcination to obtain a H-type precursor I;

[0025] (2) adding a solution containing M metal to the H-type precursor I of step (1), and subjecting to drying and reduction to obtain a precursor II;

[0026] (3) mixing the precursor II, an alkylating agent c, and a solvent to react, and subjecting to filtration, washing, and drying to obtain the catalyst.

[0027] Further, in step (1), the molecular sieve I is a basic metal type molecular sieve I.

[0028] Further, in step (1), the ammonium ion exchange is to exchange Na + , K + , or other alkali metal or alkaline earth metal cations in the basic metal type molecular sieve into NH4 +The ammonium ion exchange is carried out at 20-60℃ for 0.5-4h, and can be carried out once or more than once. The ammonium salt in the ammonium ion exchange is selected from one or more of ammonia, ammonium chloride, ammonium nitrate and ammonium carbonate. The concentration of the ammonium salt is 0.1-1.0 mol / L. After the ammonium ion exchange, the product is dried at 60-120℃ for 4-24h, and then calcined at a temperature of 400-650℃ for 1-12h in an oxygen or air atmosphere to obtain the H-type molecular sieve precursor I.

[0029] Further, in step (1), the solution containing M metal can be prepared by dissolving a soluble metal compound, wherein the metal is selected from one or more of ruthenium, platinum, palladium, copper and nickel; and the metal solution, for example, a solution of ruthenium nitrate or ruthenium chloride, is prepared to obtain a solution containing ruthenium.

[0030] Further, in step (1), the concentration of the solution containing M metal is 2-50g / L.

[0031] Further, in step (1), the solution containing M metal is added to the H-type precursor I in step (1) by dropwise addition. The present application does not have a special limitation on the dropwise addition conditions, for example, the dropwise addition can be carried out at room temperature, and the mixture is allowed to stand for 1-10h.

[0032] Further, in step (1), the mass ratio of the solute content of the solution containing M metal to the H-type precursor I in step (1) is 0.004-0.03:1.

[0033] Further, in step (1), the drying can be carried out by a conventional method, and preferably, the drying temperature is 40-90℃, and the drying time is 4-12h. The reduction can be carried out by reduction with a reducing gas, and preferably, the reduction is carried out by reduction with hydrogen. The reduction conditions are preferably as follows: the reduction temperature is 300-450℃, the reduction time is 3-6h, the volume space velocity of the reduction gas is 40-200h-1, and the reduction atmosphere is hydrogen. -1 .

[0034] Further, in step (2), the alkylating agent c is selected from one or more of methyltrimethoxysilane, dimethyldimethoxysilane, ethyltrimethoxysilane, diethyldimethoxysilane, propyltrimethoxysilane and isopropyltrimethoxysilane, and preferably, one or more of dimethyldimethoxysilane, diethyldimethoxysilane and isopropyltrimethoxysilane; and the solvent is at least one of ethanol and toluene.

[0035] Further, in step (2), the mass ratio of the added precursor II, alkylating agent c and solvent is 1:(0.05-0.40):(5-50), and preferably, 1:(0.10-0.33):(8-50).

[0036] Further, in step (2), the reaction condition of the reaction is 40-110°C, preferably 70-110°C, and the treatment time is 6-48 hours. In addition, the filtration, washing and drying can be performed in any manner known in the art. Specifically, as the filtration, for example, the obtained product mixture can be simply suction-filtered. As the washing, for example, washing with deionized water and / or ethanol can be mentioned. As the drying temperature, for example, 40-250°C, preferably 60-150°C can be mentioned, and as the drying time, for example, 8-30 hours, preferably 10-20 hours can be mentioned. The drying can be performed under normal pressure or under reduced pressure.

[0037] The third aspect of the present application provides a method for preparing cyclohexylbenzene from benzene by one-step hydrogenation using the above-mentioned catalyst.

[0038] Further, the method comprises contacting the raw material benzene with the catalyst to react to prepare cyclohexylbenzene using hydrogen as the hydrogen source.

[0039] Further, the mass ratio of the raw material benzene to the catalyst is 8-40, preferably 10-40.

[0040] Further, the reaction temperature is 100-220°C, preferably 120-200°C, and the reaction time is 2-8 hours, preferably 2.5-6 hours.

[0041] Further, the reaction hydrogen pressure is 0.8-2.5 MPa, preferably 1.0-2.5 MPa.

[0042] Compared with the prior art, the present application has the following beneficial effects:

[0043] 1. The catalyst provided by the present application has a specific composition, especially the metal is mainly distributed in the molecular sieve channel, the metal content on the outer surface is extremely low, and the outer surface of the catalyst has strong hydrophobicity, thereby having better affinity with benzene, various alkane aromatic hydrocarbons and other nonpolar substances, which is very advantageous for preventing the generation of excessive hydrogenation by-products.

[0044] 2. The preparation method according to the present application is simple to operate. After the ion-exchanged molecular sieve precursor is mixed with the M metal, the catalyst is obtained through alkylation treatment.

[0045] 3. The catalyst provided by the present application has hydrogenation and solid acid bifunctionalities, realizes the hydrogenation alkylation reaction of benzene to generate cyclohexylbenzene under mild reaction conditions, and the benzene conversion rate and the selectivity of the main product cyclohexylbenzene are very high, and the reaction system has good stability. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 XRD pattern of the catalyst prepared in Example 1. DETAILED DESCRIPTION

[0047] The present application is described in detail below by way of examples, but the scope of the present application is not limited to the following description.

[0048] When specific conditions are not mentioned in the examples, the routine conditions or the conditions recommended by the manufacturer are used. When the manufacturers of the reagents or instruments are not mentioned, the routine products available on the market are used.

[0049] In the context of the present specification, including in the examples and comparative examples below, the X-ray powder diffractometer used to analyze the phase of the sample is a Panalytical X'Pert Pro X-ray powder diffractometer, Cu Ka radiation source Nickel filter, 2 theta scan range 2-50°, operating voltage 40 kV, current 40 mA, scan rate 10° / min.

[0050] In the context of the present specification, including in the examples and comparative examples below, the pyridine adsorption infrared method (Nicolet Model 710 spectrometer) is used to determine the acid amount and acid type of the molecular sieve. The specific operation steps are as follows: a, sample pretreatment. The sample (about 30 mg) is pressed into a thin disc of 13 mm in diameter and loaded into the infrared sample cell. Then, the sample is pretreated under vacuum pool conditions and at 400°C for 1 h. After the sample cell is cooled to room temperature, the infrared data of the sample is scanned as background. b, pyridine adsorption. At room temperature and in a vacuum environment, pyridine vapor is introduced into the in-situ until the adsorption reaches equilibrium, and the adsorption time is 1 h. c, pyridine desorption. After the adsorption is completed, vacuum is extracted at 100°C until the internal pressure no longer changes, and the desorption time is 40 min, and the infrared absorption spectrum is scanned and recorded respectively. The difference spectrum before and after pyridine adsorption is the obtained pyridine adsorption-infrared absorption spectrum. The acid amount of the sample is calculated according to the spectrum:

[0051]

[0052] Wherein r and w are the diameter (cm) and mass (g) of the catalyst thin disc, A is the absorbance integral value at the specified wave number peak according to the scanned pyridine adsorption-infrared absorption spectrum. IMEC is the integral molar extinction coefficient, IMEC L is 2.22, and IMEC B is 1.67. The peak near 1545 cm -1 is B acid, and the peak near 1455 cm -1 is L acid.

[0053] In the context of the present specification, including in the examples and comparative examples below, the relative acid amount of the outer surface of the catalyst is determined using the "probe reaction" triisopropylbenzene cracking, which is carried out by preparing a chromatographic column sample of 50 mg of catalyst mixed with 100 mg of quartz sand, followed by injecting 1 μL of triisopropylbenzene liquid per time at 250 °C by gas chromatography (GC, Agilent 7890B), followed by evaluating the relative acid amount and activity of the outer surface of the catalyst based on the yield of cyclohexene in the chromatogram, in comparison with the "metal-molecular sieve" structure without alkylation treatment, according to the following calculation method:

[0054] Relative acid amount of the outer surface = (alkylated group propylene yield / (3 x alkylation group triisopropylbenzene input)) / (non-alkylated group propylene yield / (3 x non-alkylated group triisopropylbenzene input)) x 100%.

[0055] In the context of the present specification, including in the examples and comparative examples below, the total pore volume, the total specific surface area and the external specific surface area of the catalyst are determined by nitrogen physical adsorption-desorption (BET method): the nitrogen physical adsorption-desorption isotherm of the molecular sieve is determined using a physical adsorption instrument (such as a Micromeretic ASAP2020M physical adsorption instrument), and then calculated by the BET equation and the t-plot equation.

[0056] In the context of the present specification, including in the examples and comparative examples below, the inductively coupled plasma atomic emission spectrometry (ICP) used is a Varian 725-ES, and the content of the elements, in moles, is determined by dissolving the analysis sample with hydrofluoric acid to detect the content of the metal M in the sample.

[0057] According to the present application, including in the examples and comparative examples below, the metal M in the catalyst is mainly distributed in the pores of the molecular sieve. The mass content of the outer surface metal M in the outer surface elements can be determined according to the XPS (X-ray photoelectron spectroscopy) test of the state of the elements on the surface of the molecular sieve. The X-ray photoelectron spectrometer (XPS) of the molecular sieve is a Thermo ESCA LAB-250 type X-ray photoelectron spectrometer, and the C1s = 284.6 eV is used as an internal standard to correct the measured element signal.

[0058] And the proportion of the outer surface metal content to the total metal content is approximately calculated by the following formula:

[0059] Proportion of the outer surface metal M = (mass content of the outer surface metal in the outer surface elements * external specific surface area of the catalyst) / total metal content in the catalyst * specific surface area of the catalyst,

[0060] That is, since the metal M in the catalyst is uniformly supported on the inner and outer surfaces of the molecular sieve by a simple impregnation method, the proportion of the metal M on the outer surface is in direct proportion to the proportion of the metal relative distribution and in direct proportion to the proportion of the outer specific surface area of the catalyst.

[0061] In the context of the present specification, including in the examples and comparative examples below, the mass content of the substituent R is determined by the proportion of mass loss under oxygen atmosphere thermogravimetric analysis (TGA), wherein the thermogravimetric analyzer used is a model SDT Q600 of the TA Instrument Company.

[0062] In the context of the present specification, the reaction product caprolactone is qualitatively analyzed by gas chromatography-mass spectrometry (GC-MS), and the yield of the product caprolactone and the conversion rate of the reaction substrate cyclohexanone are analyzed by gas chromatography (GC). The gas chromatography-mass spectrometer is an Agilent 7890A of Agilent Technologies, Inc., the chromatographic column is an HP-5 non-polar capillary column (30 m, 0.53 mm), the gas chromatograph is an Agilent 7890B, the detector is a flame ionization detector (FID), and the chromatographic column is an SE-54 capillary column (30 m, 0.53 mm).

[0063] The formula for calculating the yield and selectivity of the product cyclohexylbenzene is:

[0064] The yield % of the product cyclohexylbenzene = (the molar amount of cyclohexylbenzene generated by the reaction x 2) / (the molar amount of benzene as the reaction substrate) x 100%.

[0065] The selectivity % of the product cyclohexylbenzene = (the molar amount of cyclohexylbenzene generated by the reaction x 2) / (the molar amount of benzene as the reaction substrate) x 100%.

[0066] Example 1

[0067] The Na-type MWW molecular sieve with a silicon-aluminum molar ratio of 25:1 was subjected to ammonium ion exchange with a 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 45°C for 2 hours, then centrifuged and washed, and the sample obtained after repeating the ammonium ion exchange twice was oven-dried overnight at 100°C and calcined in air at 550°C for 6 hours to prepare a precursor I of H type.

[0068] 4 mL of a 3.2 g / L ruthenium chloride solution was added dropwise to 1 g of the precursor I. After drying at 80°C for 2 h, the precursor II was prepared by reduction in a fixed bed reactor at 350°C under a hydrogen gas volume space velocity of 50 h-1 for 3 h. -1

[0069] 0.2 g of methyltrimethoxysilane was mixed with 1 g of the precursor II and 10 mL of toluene solvent, and after refluxing at 110°C for 24 h, the mixture was centrifuged with water, washed, and dried at 80°C for 12 h to obtain the catalyst. ​

[0070] The XRD pattern of the catalyst is shown in Figure 1 Table 1. The XRD pattern shows that the catalyst retains the MWW structure as a whole. The catalyst specific surface area, pore volume, acid properties (including total acid amount and external surface acid amount equivalent), metal content and external surface metal content are shown in Table 1.

[0071] Example 2

[0072] Na-type MWW molecular sieve with a silicon-aluminum molar ratio of 25:1 was subjected to ammonium ion exchange with a 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 45°C for 2 hours, and then centrifuged and washed. The sample obtained after repeating the ammonium ion exchange twice was dried overnight at 100°C, and H-type precursor I was prepared by calcining the dried sample in air at 550°C for 6 hours.

[0073] A 3.2 g / L ruthenium chloride solution was taken in an amount of 4 mL, and added dropwise to 1 g of the precursor I. After drying at 80°C for 2 hours, the precursor II was prepared by reduction in a fixed bed reactor at 350°C under a hydrogen gas volume space velocity of 50 h -1 for 3 hours.

[0074] A 0.3 g dimethyl dimethoxysilane was mixed with 1 g of the precursor II and 15 mL of toluene solvent, and refluxed at 110°C for 24 hours. After centrifugation and washing with water, the catalyst was obtained by drying at 80°C for 12 hours.

[0075] The XRD pattern of the catalyst is shown in Figure 1 . The catalyst specific surface area, pore volume, acid properties (including total acid amount and external surface acid amount), metal content and external surface metal content are shown in Table 1.

[0076] Example 3

[0077] Na-type FAU molecular sieve with a silicon-aluminum molar ratio of 10:1 was subjected to ammonium ion exchange with a 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 45°C for 2 hours, and then centrifuged and washed. The sample obtained after repeating the ammonium ion exchange twice was dried overnight at 100°C, and H-type precursor I was prepared by calcining the dried sample in air at 550°C for 6 hours.

[0078] A 3.2 g / L ruthenium chloride solution was taken in an amount of 6 mL, and added dropwise to 1 g of the precursor I. After drying at 80°C for 2 hours, the precursor II was prepared by reduction in a fixed bed reactor at 350°C under a hydrogen gas volume space velocity of 100 h -1 for 3 hours.

[0079] Take 0.3 g ethyl trimethoxysilane and 1 g precursor II, and 15 mL toluene solvent mixture, reflux at 110°C for 24 h, centrifugal washing with water, drying at 80°C for 12 h, to obtain the catalyst.

[0080] The XRD of the obtained catalyst retains the FAU molecular sieve structure as a whole. The specific surface area, pore volume, acid properties (including total acid amount and external surface acid amount equivalent), metal content and external surface metal content of the catalyst are shown in Table 1.

[0081] Example 4

[0082] The Na-type FAU molecular sieve with a silicon-aluminum molar ratio of 5:1 was subjected to ammonium ion exchange with a 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 45°C for 2 h, then centrifugal washing, and the sample obtained after repeating the ammonium ion exchange twice was oven dried overnight at 100°C and calcined in air at 550°C for 6 h to prepare the H-type precursor I.

[0083] Take 3 mL of 2.6 g / L palladium chloride solution and drop it on 1 g of precursor I. After drying at 80°C for 2 h, reduce it in a fixed bed reactor at 350°C, hydrogen gas hourly space velocity of 100 h -1 for 3 h to prepare the precursor II.

[0084] Take 0.2 g isopropyl trimethoxysilane and 1 g of precursor II, and 10 mL of toluene solvent mixture, reflux at 110°C for 24 h, centrifugal washing with water, drying at 80°C for 12 h, to obtain the catalyst. The XRD of the obtained catalyst retains the FAU molecular sieve structure as a whole. The specific surface area, pore volume, acid properties (including total acid amount and external surface acid amount equivalent), metal content and external surface metal content of the catalyst are shown in Table 1.

[0085] Example 5

[0086] 1. Catalyst preparation:

[0087] Take 4 mL of 3.2 g / L ruthenium chloride solution and drop it on 1 g of H-type ATS molecular sieve with a silicon-aluminum molar ratio of 10:1. After drying at 80°C for 2 h, reduce it in a fixed bed reactor at 350°C, hydrogen gas hourly space velocity of 50 h -1 for 3 h to prepare the precursor II.

[0088] Take 0.2 g isopropyl trimethoxysilane and 1 g of precursor II, and 10 mL of toluene solvent mixture, reflux at 110°C for 24 h, centrifugal washing with water, drying at 80°C for 12 h, to obtain the catalyst.

[0089] The XRD pattern of the obtained catalyst is similar to that of the ATS molecular sieve. The specific surface area, pore volume, acid properties (including total acid amount and external surface acid amount), metal content and external surface metal content of the catalyst are shown in Table 1.

[0090] Example 6

[0091] 1. Catalyst preparation:

[0092] The preparation method is the same as that of Example 1, except that the raw material is changed to Na-type MWW molecular sieve with a silicon-aluminum molar ratio of 50:1, and the remaining steps remain unchanged. The catalyst properties are shown in Table 1.

[0093] The XRD pattern of the obtained catalyst is similar to that of the ATS molecular sieve. Figure 1 The specific surface area, pore volume, acid properties (including total acid amount and external surface acid amount), metal content and external surface metal content of the catalyst are shown in Table 1.

[0094] Examples 7-10

[0095] Take 0.25 g of the catalyst synthesized in Example 1 and add it to a high-pressure reaction kettle, then add 8 g of benzene to the kettle, and charge hydrogen gas to make the system pressure reach 1.2 MPa. Then heat the system to 150°C, and after 4 h of reaction, the reaction is stopped.

[0096] Example 11

[0097] Take 0.25 g of the catalyst synthesized in Example 2 and add it to a high-pressure reaction kettle, then add 8 g of benzene to the kettle, and charge hydrogen gas to make the system pressure reach 1.2 MPa. Then heat the system to 150°C, and after 4 h of reaction, the reaction is stopped.

[0098] For ease of comparison, the evaluation data are summarized in Table 2.

[0099] Example 12

[0100] Take 0.25 g of the catalyst synthesized in Example 3 and add it to a high-pressure reaction kettle, then add 8 g of benzene to the kettle, and charge hydrogen gas to make the system pressure reach 1.2 MPa. Then heat the system to 150°C, and after 4 h of reaction, the reaction is stopped.

[0101] For ease of comparison, the evaluation data are summarized in Table 2.

[0102] Example 13

[0103] Take 0.25 g of the catalyst synthesized in Example 4 and add it to a high-pressure reaction kettle, then add 8 g of benzene to the kettle, and charge hydrogen gas to make the system pressure reach 1.2 MPa. Then heat the system to 150°C, and after 4 h of reaction, the reaction is stopped.

[0104] For ease of comparison, the evaluation data are summarized in Table 2.

[0105] Example 14

[0106] Example 14

[0107] For comparison purposes, the evaluation data are summarized in Table 2.

[0108] Example 15

[0109] Example 15

[0110] For comparison purposes, the evaluation data are summarized in Table 2.

[0111] Comparative Example 1

[0112] 1. Catalyst preparation:

[0113] The preparation method corresponds to Example 1, except that the treatment with methyltrimethoxysilane was omitted, i.e. precursor II was evaluated as catalyst without further treatment. The catalyst properties are summarized in Table 1.

[0114] 2. Catalyst evaluation:

[0115] The catalyst evaluation method corresponds to Example 11.

[0116] For comparison purposes, the evaluation data are summarized in Table 2.

[0117] Comparative Example 2

[0118] 1. Catalyst preparation:

[0119] The preparation method corresponds to Example 1, except that the amount of ruthenium chloride added was increased to 20 mL, i.e. only the metal content of the catalyst was increased. The catalyst properties are summarized in Table 1.

[0120] 2. Catalyst evaluation:

[0121] The catalyst evaluation method corresponds to Example 11.

[0122] For comparison purposes, the evaluation data are summarized in Table 2.

[0123] Comparative Example 3

[0124] 1. Catalyst preparation:

[0125] The preparation method is according to Example 2, only the addition of "0.3 g dimethyl dimethoxysilane" is changed to 1.0 g dimethyl dimethoxysilane, and the rest of the steps remain unchanged. The catalyst properties are shown in Table 1.

[0126] 2. Catalyst evaluation:

[0127] The catalyst evaluation method is according to Example 11.

[0128] The catalyst evaluation results are listed in Table 2 for easy comparison.

[0129] Comparative Example 4

[0130] 1. Catalyst preparation:

[0131] The molecular sieve in Example 1 is selected.

[0132] 2. Catalyst evaluation:

[0133] The catalyst evaluation method is according to Example 11, only the hydrogen partial pressure in the reaction conditions is changed to 4.0 MPa, and the rest of the operations remain unchanged.

[0134] The catalyst evaluation results are listed in Table 2 for easy comparison.

[0135] Table 1 Physical and chemical properties of catalysts obtained in each example and comparative example

[0136]

[0137]

[0138] Table 1 (continued)

[0139]

[0140] Table 2 Catalytic performance of catalysts obtained in each example and comparative example

[0141]

[0142]

[0143] Example 16

[0144] The catalyst prepared in Example 1 is washed and dried, and then used in the next reaction, a total of 6 reaction cycles. Among them, the catalyst evaluation is to add 8 g of benzene into the high-pressure reaction kettle, and fill hydrogen to make the system pressure reach 1.2 MPa. Then the system is heated to 150°C, and the reaction is terminated after 4 h.

[0145] Table 3

[0146] Number of recycling cycles Yield of cyclohexylbenzene (%) Selectivity of cyclohexylbenzene (%) 1 61 90.8 2 60 91.3 3 61 91.1 4 59 90.4 5 58 91.1 6 61 91.2

[0147] It should be noted that the foregoing examples have been provided merely for the purposes of illustration and are not intended to limit the application thereof in any way. The application has been described in reference to various exemplary embodiments and its terminology has been used for the purpose of description. The terminology is not intended to be limiting, but rather exemplary. Changes and modifications can be made to the application without departing from the spirit and scope thereof. The application described herein is intended to cover all alternatives, modifications, additions and subtractions falling within the scope of the application as defined by the claims.

Claims

1. A catalyst for producing cyclohexylbenzene, characterized by, The catalyst comprises a molecular sieve, an active metal M and an R group; The active metal M is selected from one or more of ruthenium, platinum, palladium, copper and nickel; The R group is selected from at least one of C1-C4 alkyl groups; The mass content of the active metal M in the catalyst is 0.2%-1.5% based on the mass of the catalyst; the mass content of the metal M on the outer surface of the catalyst is 0.4% or less based on the mass of the outer surface elements; and the content of the metal M on the outer surface accounts for 1.2%-20% of the total content of the metal M in the catalyst. The molecular sieve in the catalyst is selected from at least one of MWW, FAU, MOR, BEA and ATS. The mass content of the substituent R in the catalyst is 1%-10% based on the mass of the catalyst.

2. The catalyst according to claim 1, characterized in that, The mass content of the active metal M in the catalyst is 0.2%-1.2% based on the mass of the catalyst.

3. The catalyst of claim 1, wherein The content of the molecular sieve in the catalyst is 90%-98% based on the mass of the catalyst, and the silica-alumina ratio is 2-50.

4. The catalyst of claim 3, wherein The silica-alumina ratio of the molecular sieve in the catalyst is 4-40.

5. The catalyst of claim 1, wherein The specific surface area of the catalyst is 380-800 m 2 / g; the total pore volume of the catalyst is not less than 0.15 cm 3 / g.

6. The catalyst of claim 5, wherein The specific surface area of the catalyst is 400-700 m 2 / g; the total pore volume of the catalyst is 0.2-0.9 cm 3 / g.

7. The catalyst of claim 1, wherein The total acid amount of the catalyst is 400-1500 pmol-g -1 .

8. The catalyst of claim 1, wherein The relative acid equivalent of the outer surface of the catalyst is 30%-50%. The ratio of the B acid / L acid in the catalyst is 0.2-6.

0.

9. A preparation method of the catalyst for producing cyclohexylbenzene according to any one of claims 1-8, comprising the following steps: (1) ammonium ion exchange and calcination of a molecular sieve I to obtain a H-type precursor I; (2) adding a solution containing M metal to the H-type precursor I of step (1), drying and reducing to obtain a precursor II; (3) mixing the precursor II, an alkylating agent c and a solvent, filtering, washing and drying to obtain the catalyst.

10. The method of claim 9, wherein, In step (2), the concentration of the solution containing M metal is 2-50 g / L.

11. The preparation method according to claim 9, characterized in that, In step (3), the alkylating agent c is selected from one or more of methyltrimethoxysilane, dimethyldimethoxysilane, ethyltrimethoxysilane, diethyldimethoxysilane, propyltrimethoxysilane and isopropyltrimethoxysilane; and the solvent is at least one of ethanol and toluene.

12. The method of claim 11, wherein, In step (3), the alkylating agent c is selected from one or more of dimethyldimethoxysilane, diethyldimethoxysilane and isopropyltrimethoxysilane.

13. The preparation method according to claim 9, characterized in that, In step (3), the mass ratio of the precursor II, the alkylating agent c and the solvent is 1:(0.05-0.40):(5-50).

14. A method for producing cyclohexylbenzene by one-step hydrogenation of benzene using the catalyst according to any one of claims 1-8.

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