Process for the one-step production of cyclohexylbenzene by hydrogenation of benzene

Abstract

This invention discloses a one-step method for the hydrogenation of benzene to produce cyclohexylbenzene. The method includes a contact reaction between benzene and a catalyst, using hydrogen as the hydrogen source to produce cyclohexylbenzene. The catalyst comprises a molecular sieve, an active metal M, and an R group; wherein the R group is selected from at least one of phenyl, benzyl, and phenethyl; and the total acidity of the catalyst is 400–1500 μmol·g. ‑1 The catalyst has an outer surface relative acid equivalent of 15% to 35%. The method provided by this invention features good product selectivity and a low amount of cyclohexane as a byproduct.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, and specifically to a one-step method for producing cyclohexylbenzene by hydrogenation alkylation of benzene. Background Technology

[0002] Cyclohexylbenzene is an important chemical intermediate. After oxidation and acid-catalyzed hydrolysis, it can be used to co-produce two important chemical products, phenol and cyclohexanone (CN104640827A, CN104245642A, etc.), and then further synthesize bulk chemicals such as phenolic resin and nylon 6.

[0003] Methods for producing cyclohexylbenzene from benzene hydrogenation include: alkylation of benzene with the hydrogenation product cyclohexene, selective hydrogenation of biphenyl, and a one-step method for producing cyclohexylbenzene via benzene hydrogenation alkylation. Among these, the one-step method involves mixing benzene with hydrogen gas. Under the action of a hydrogenation / alkylation bifunctional catalyst, the 6-membered cyclic hydrocarbon intermediate (such as cyclohexene) obtained from benzene hydrogenation is directly reacted with the benzene feedstock at the alkylation catalytic center to yield the cyclohexylbenzene product without separation. Compared to the other two methods, this method has advantages such as lower feedstock costs, milder catalytic conditions, and simpler post-processing.

[0004] Currently, common bifunctional catalysts for benzene hydroalkylation mainly consist of combinations of hydrogenation metals and solid acid supports. For example, CN104105679A and US4219689 disclose the applications of two catalytic systems—hydrogenation metal / MCM-22 molecular sieve and Ni-rare earth / HY molecular sieve—in the benzene hydroalkylation reaction, respectively. However, these bifunctional catalysts suffer from the practical problem of excessive metal hydrogenation activity, which is mismatched with the catalytic strength of the alkylation center, leading to an excessive amount of over-hydrogenation byproduct cyclohexane. This, in turn, results in less than ideal selectivity for the target product cyclohexylbenzene (typically not exceeding 75%), affecting the economic value of this route. Summary of the Invention

[0005] The technical problem this invention aims to solve is the low product selectivity and high cyclohexane byproduct associated with the hydrogenation alkylation of benzene to produce cyclohexylbenzene in existing technologies. This invention provides a one-step method for producing cyclohexylbenzene via benzene hydrogenation. The method provided by this invention features good product selectivity and a lower cyclohexane byproduct.

[0006] The first aspect of this invention provides a method for one-step preparation of cyclohexylbenzene by benzene hydrogenation, comprising a contact reaction between benzene and a catalyst, using hydrogen as a hydrogen source to obtain cyclohexylbenzene; the catalyst comprises a molecular sieve, an active metal M group, and an R group;

[0007] Among them, the active metal M is selected from one or more of ruthenium, platinum, palladium, copper and nickel;

[0008] Wherein, the R group is selected from at least one of phenyl, benzyl, and phenethyl;

[0009] The total acidity of the catalyst is 400–1500 μmol·g. -1 The catalyst has an outer surface relative acid equivalent of 15% to 35%.

[0010] Furthermore, based on the mass of the catalyst, the mass content of M is 0.22% to 1.5%, and the ratio of the metal M content on the outer surface of the catalyst to the outer surface elements is less than 0.3%, preferably 0.01% to 0.2%; the outer surface metal M accounts for only 1% to 12% of the total metal content in the catalyst, preferably 1.5% to 10%.

[0011] Furthermore, M is preferably a ruthenium or / and palladium metal element.

[0012] Furthermore, in the catalyst, the mass content of M is preferably 0.1% to 1.5%, more preferably 0.2% to 1.2%, based on the mass of the catalyst, for example, but not limited to 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc.

[0013] Furthermore, in the catalyst, the mass content of substituent R is 2% to 20% based on the mass of the catalyst.

[0014] Furthermore, in the catalyst, M exists in at least one of the following forms: element, oxide, chloride, and nitrate.

[0015] Furthermore, the molecules in the catalyst are screened from at least one of MWW, FAU, MOR, BEA, and ATS.

[0016] Furthermore, the molecular sieve accounts for 80%-95% of the catalyst mass, and the silicon-aluminum molar ratio is 2-50, preferably 4-40.

[0017] Furthermore, the specific surface area of ​​the catalyst is 385–500 m². 2 / g, preferably 410~490m 2 / g; the total pore volume of the catalyst is not less than 0.18 cm³. 3 / g, preferably 0.18~1.0cm 3 / g.

[0018] Furthermore, the total acidity of the catalyst is 500–1300 μmol·g. -1 The relative acid equivalent of the outer surface area of ​​the catalyst is preferably 20% to 35%.

[0019] Furthermore, the method for preparing the catalyst includes the following steps:

[0020] (1) Mix the solution containing metal M with H-type molecular sieve precursor I, and then dry and reduce it to obtain precursor II;

[0021] (2) The precursor II, aryl reagent C and solvent are mixed and reacted, and the catalyst is obtained by filtration, washing and drying.

[0022] Further, in step (1), the H-type molecular sieve precursor I can be obtained by calcining an alkali metal molecular sieve precursor through ammonium ion exchange. The ammonium ion exchange of the alkali metal molecular sieve precursor I involves removing Na+ from the alkali metal molecular sieve precursor I. + K + Alkali metal or alkaline earth metal cations are exchanged to NH4 + The ammonium ions are exchanged at 20–60℃ for 0.5–4 hours, and can be exchanged once or multiple times. 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 mol / L to 1 mol / L. After the ammonium ion exchange, the mixture is dried at 60–120℃ for 4–24 hours, and then calcined at 400–650℃ for 1–12 hours in an oxygen or air atmosphere to obtain H-type molecular sieve precursor I.

[0023] Further, in step (1), the solution containing metal M can be prepared using a soluble metal compound, wherein the metal is selected from one or more of ruthenium, platinum, palladium, copper and nickel; the metal solution, taking ruthenium as an example, is prepared by using ruthenium nitrate or ruthenium chloride to obtain a ruthenium-containing solution.

[0024] Furthermore, in step (1), the concentration of the solution containing metal M is 1.5–45 g / L.

[0025] Furthermore, in step (1), the solution containing metal M is added dropwise to the H-type precursor I in step (1). This invention does not impose particular limitations on the dropwise addition conditions; for example, it can be added dropwise at room temperature and then mixed for 1 to 10 hours.

[0026] Further, in step (1), the solute content of the solution containing metal M is 0.005 to 0.035:1 in mass ratio with respect to the H-type precursor I in step (1).

[0027] Further, in step (1), the drying can be carried out using conventional methods, preferably with a drying temperature of 40–90°C and a drying time of 4–12 hours. The reduction can be carried out using a reducing gas, preferably hydrogen reduction, with the following preferred reduction conditions: a reduction temperature of 300–450°C, a reduction time of 3–6 hours, and a volume hourly space velocity (VHSV) of 40–200 h⁻¹. -1 .

[0028] Further, in step (2), the arylating agent c is selected from one or more of phenyltrimethoxysilane, tolyltrimethoxysilane, phenylsilanetriol, tolylsilanetriol, and diphenylsilanediol; the solvent is at least one of ethanol or toluene.

[0029] Further, in step (2), the mass ratio of the added precursor II, arylating agent c, and solvent is 1:(0.06~0.45):(6~55), preferably 1:(0.12~0.35):(7.5~52).

[0030] Further, in step (2), the reaction conditions are 40–110°C, preferably 70–110°C, and the processing time is 6–48 h. Additionally, the filtration, washing, and drying can be performed in any manner conventionally known in the art. Specifically, for example, the filtration can be performed by simply filtration of the obtained product mixture. For example, washing can be performed using deionized water and / or ethanol. For example, the drying temperature can be 40–250°C, preferably 60–150°C, and the drying time can be 8–30 hours, preferably 10–20 hours. The drying can be carried out under normal pressure or under reduced pressure.

[0031] Furthermore, in the reaction, the mass ratio of the raw material benzene to the catalyst is 8 to 40, preferably 10 to 40.

[0032] Furthermore, in the reaction, the reaction temperature is 100–220°C, preferably 120–200°C; the reaction time is 2–8 hours, preferably 2.5–6 hours.

[0033] Furthermore, the reaction hydrogen pressure is 0.8–2.5 MPa, preferably 1.0–2.5 MPa.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] In the one-step hydrogenation method for cyclohexylbenzene of benzene provided by this invention, the catalyst has a specific composition. In particular, due to its low acid content on its outer surface, it primarily utilizes the acid sites within the molecular sieve channels to enhance catalytic performance. Furthermore, the metal is preferably concentrated mainly within the molecular sieve channels, with extremely low metal content on the outer surface. Moreover, the catalyst's outer surface exhibits strong hydrophobicity, thus demonstrating better affinity for benzene, various alkanes, and aromatics—non-polar substances—which is highly advantageous in preventing the formation of excessive hydrogenation byproducts. Furthermore, the catalyst possesses dual functions as both a hydrogenation catalyst and a solid acid, enabling the hydrogenation alkylation of benzene to cyclohexylbenzene under mild reaction conditions. Both the benzene conversion and the selectivity of the main product, cyclohexylbenzene, are very high, and the reaction system exhibits excellent stability. Attached Figure Description

[0036] Figure 1 The image shows the XRD pattern of the catalyst prepared in Example 1. Detailed Implementation

[0037] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited to the following description.

[0038] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0039] In the context of this specification, including in the following examples and comparative examples, the X-ray powder diffractometer used for the samples is a Panalytical X-PERPRO type X-ray powder diffractometer, and the CuKα-ray source is used to analyze the phase composition of the samples. Nickel filter, 2θ scanning range 2~50°, operating voltage 40kV, current 40mA, scanning rate 10° / min.

[0040] In the context of this specification, including in the following examples and comparative examples, the scanning electron microscope (SEM) used for the samples is a model S-4800II field emission scanning electron microscope.

[0041] In the context of this specification, including the following examples and comparative examples, the acid content of molecular sieves was determined using the pyridine adsorption infrared method (Nicolet Model 710 spectrometer). The specific operating steps are as follows: a) Sample pretreatment. The sample (approximately 30 mg) was compressed into a thin disc with a diameter of 13 mm and placed in the infrared sample cell. The sample was then pretreated in a vacuum chamber at 400°C for 1 hour. After the sample cell cooled to room temperature, the infrared data of the sample was scanned as background. b) Pyridine adsorption. Pyridine vapor was introduced into the in-situ under room temperature and vacuum conditions until adsorption reached equilibrium, with an adsorption time of 1 hour. c) Pyridine desorption. After adsorption, a vacuum was applied at 100°C until the internal pressure no longer changed, with a desorption time of 40 minutes. The infrared absorption spectra were then scanned and recorded. The difference spectrum before and after pyridine adsorption is the obtained pyridine adsorption-infrared absorption spectrum. The acid content of the sample was calculated based on the spectrum.

[0042]

[0043] Where r and w are the diameter (cm) and mass (g) of the catalyst disc, respectively, and A is the integral absorbance value at the specified wavenumber peak based on the scanned pyridine adsorption-infrared absorption spectrum. IMEC is the integral molar extinction coefficient. L Version 2.22, IMEC B It is 1.67.

[0044] In the context of this specification, including the following examples and comparative examples, the acidity of the catalyst's outer surface was characterized by a "probe reaction" involving the cleavage of triisopropylbenzene. Specifically, a chromatographic column sample consisting of 50 mg of catalyst and 100 mg of quartz sand was prepared and injected into a gas chromatograph (GC, Agilent 7890B) at 250°C with 1 μL of triisopropylbenzene liquid injected each time. The relative acidity and activity of the catalyst's outer surface were then evaluated based on the yield of cyclohexene in the chromatography, compared to the unarylated "metal-molecular sieve" structure. The specific calculation method is as follows:

[0045] Relative acid equivalent of outer surface = (propylene yield of arylated group / (3 × triisopropylbenzene added to arylated group)) / (propylene yield of non-arylated group / (3 × triisopropylbenzene added to non-arylated group)) × 100%.

[0046] In the context of this specification, including in the following examples and comparative examples, the total pore volume, total specific surface area, and external specific surface area of ​​the catalyst were measured by the nitrogen physical adsorption-desorption method (BET method): the nitrogen physical adsorption-desorption isotherm of the molecular sieve was measured using a physical adsorption instrument (such as a Micromeretic ASAP2020M physical adsorption instrument), and then calculated using the BET equation and the t-plot equation.

[0047] In the context of this specification, including in the following examples and comparative examples, the inductively coupled plasma atomic emission spectrometer (ICP) model used is Varian 725-ES, and the content of elements, in molar terms, is determined by dissolving the sample in hydrofluoric acid, including the determination of the total content of metal M in the sample.

[0048] According to the present invention, in the following examples and comparative examples, the metal M in the catalyst is mainly distributed within the pores of the molecular sieve. The mass content of the outer surface metal M relative to the outer surface elements can be determined by testing the elemental state of the molecular sieve surface using XPS (X-ray photoelectron spectroscopy). The X-ray photoelectron spectrometer (XPS) used for the molecular sieve is a Thermo ESCA LAB-250 X-ray photoelectron spectrometer, and the measured elemental signal is calibrated using C1s = 284.6 eV as an internal standard.

[0049] The proportion of the outer surface metal content to the total metal content can be approximately calculated using the following formula:

[0050] The proportion of metal on the outer surface (M) = (the content of metal on the outer surface as a percentage of the total elemental content * the specific surface area of ​​the catalyst) / (the metal content in the catalyst * the specific surface area of ​​the catalyst).

[0051] 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 metal M on the outer surface is not only proportional to the relative distribution of the metal, but also proportional to the proportion of the specific surface area of ​​the catalyst.

[0052] In the context of this specification, including the following examples and comparative examples, the mass content of substituent R was determined by the mass loss ratio under oxygen atmosphere thermogravimetric analysis (TGA), wherein the thermogravimetric analyzer used was a TA Instrument SDT Q600 model.

[0053] In the context of this specification, the reaction product caprolactone was qualitatively analyzed by gas chromatography-mass spectrometry (GC-MS), and the yield of caprolactone and the conversion of the reaction substrate cyclohexanone were analyzed by gas chromatography (GC). The GC-MS system was an Agilent 7890A from Agilent Technologies, USA, with an HP-5 nonpolar capillary column (30 m, 0.53 mm). The gas chromatograph was an Agilent 7890B, with a flame ionization detector (FID) and an SE-54 capillary column (30 m, 0.53 mm).

[0054] The formulas for calculating the yield and selectivity of the product cyclohexylbenzene are as follows:

[0055] The yield % of the product cyclohexylbenzene = (molar amount of cyclohexylbenzene produced in the reaction × 2) / (molar amount of the substrate benzene) × 100%.

[0056] The selectivity % of the product cyclohexylbenzene = (molar amount of cyclohexylbenzene produced in the reaction × 2) / (molar amount of benzene reacted) × 100%.

[0057] Example 1

[0058] (1) Preparation of H-type MWW molecular sieve precursor I

[0059] Na-type MWW molecular sieve with a silicon-to-aluminum molar ratio of 20:1 was subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 45 °C for 2 hours. After centrifugation and washing, the ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100 °C and calcined in air at 550 °C for 6 hours to obtain H-type precursor I.

[0060] (2) Catalyst preparation

[0061] 1 mL of an 8 g / L ruthenium chloride solution was added dropwise to 1 g of H-type MWW molecular sieve precursor I with a silicon-to-aluminum ratio of 20:1. After drying at 80 °C for 2 h, the mixture was placed in a fixed-bed reactor at 400 °C and a hydrogen hourly space velocity of 80 h⁻¹. -1 Precursor II was obtained by reducing it for 2 hours under the specified conditions.

[0062] 0.3 g of phenyltrimethoxysilane was mixed with 1 g of precursor II and 20 mL of ethanol solvent, refluxed at 75 °C for 24 h, centrifuged with water, washed, and dried at 80 °C for 12 h to obtain the catalyst.

[0063] The obtained catalyst XRD pattern is as follows Figure 1 As shown in the figure, XRD analysis reveals that the catalyst retains the overall structure of the MWW molecular sieve. The specific surface area, pore volume, acidity properties (including total acidity and external surface acidity equivalent), metal content, and external surface metal content of the catalyst are shown in Table 1.

[0064] Example 2

[0065] (1) Preparation of H-type MWW molecular sieve precursor I

[0066] The preparation process is the same as in Example 1, using Na-type MWW molecular sieve with a silicon-to-aluminum molar ratio of 25:1.

[0067] (2) Preparation of catalyst

[0068] 2 mL of an 8 g / L ruthenium chloride solution was added dropwise to 1 g of H-type MWW molecular sieve precursor I with a silicon-to-aluminum ratio of 25:1. After drying at 80 °C for 2 h, the mixture was placed in a fixed-bed reactor at 400 °C and a hydrogen hourly space velocity of 80 h⁻¹. -1 Precursor II was obtained by reducing it for 3 hours under the specified conditions.

[0069] 0.2 g of tolyltrimethoxysilane was mixed with 1 g of precursor II and 20 mL of toluene solvent. The mixture was refluxed at 110 °C for 24 h, centrifuged with water, washed, and dried at 80 °C for 12 h to obtain the catalyst.

[0070] The obtained catalyst XRD pattern is the same as Figure 1 The specific surface area, pore volume, acidity properties (including total acidity and external surface acidity), metal content, and external surface metal content of the catalyst are shown in Table 1.

[0071] Example 3

[0072] (1) Preparation of H-type MOR molecular sieve precursor I

[0073] The preparation process is the same as in Example 1, using Na-type MOR molecular sieves with a silicon-to-aluminum molar ratio of 10:1.

[0074] (2) Preparation of catalyst

[0075] 1 mL of an 8 g / L ruthenium chloride solution was added dropwise to 1 g of H-type MOR molecular sieve precursor I with a silicon-to-aluminum ratio of 10:1. After drying at 80 °C for 2 h, the mixture was placed in a fixed-bed reactor at 350 °C and a hydrogen volume hourly space velocity of 150 h⁻¹. -1 Precursor II was obtained by reducing it for 3 hours under the specified conditions.

[0076] 0.3 g of phenylsilanetriol was mixed with 1 g of precursor II and 30 mL of toluene solvent, refluxed at 110 °C for 24 h, centrifuged with water, washed, and dried at 80 °C for 12 h to obtain the catalyst.

[0077] The resulting catalyst retains the overall structure of the MOR molecular sieve. The specific surface area, pore volume, acidity properties (including total acidity and external surface acidity equivalent), metal content, and external surface metal content of the catalyst are shown in Table 1.

[0078] Example 4

[0079] (1) Preparation of H-type MOR molecular sieve precursor I

[0080] The preparation process is the same as in Example 1, using Na-type MOR molecular sieves with a silicon-to-aluminum molar ratio of 15:1.

[0081] (2) Preparation of catalyst

[0082] 1 mL of an 8 g / L palladium chloride solution was added dropwise to 1 g of H-type MOR molecular sieve precursor I with a silicon-to-aluminum ratio of 15:1. After drying at 80 °C for 2 h, the mixture was then placed in a fixed-bed reactor at 350 °C and a hydrogen hourly space velocity of 80 h⁻¹. -1 Precursor II was obtained by reducing it for 3 hours under the specified conditions.

[0083] 0.2 g of diphenylsilanediol was mixed with 1 g of precursor II and 20 mL of ethanol solvent. The mixture was refluxed at 75 °C for 24 h, centrifuged with water, washed, and dried at 80 °C for 12 h to obtain the catalyst. The obtained catalyst retained the MOR molecular sieve structure as a whole. The specific surface area, pore volume, acidity properties (including total acid content and external surface acid equivalent), metal content, and external surface metal content of the catalyst are shown in Table 1.

[0084] Example 5

[0085] 1. Catalyst preparation:

[0086] 1.2 mL of an 8 g / L ruthenium chloride solution was added dropwise onto 1 g of an H-type ATS molecular sieve with a silicon-to-aluminum molar ratio of 10:1. After drying at 80 °C for 2 h, the solution was placed in a fixed-bed reactor at 350 °C and a hydrogen hourly space velocity of 80 h⁻¹. -1 Precursor II was obtained by reducing it for 3 hours under the specified conditions.

[0087] 0.2 g of phenyltrimethoxysilane was mixed with 1 g of precursor II and 10 mL of toluene solvent. The mixture was refluxed at 110 °C for 24 h, centrifuged with water, washed, and dried at 80 °C for 12 h to obtain the catalyst.

[0088] The resulting catalyst retains the overall structure of the ATS molecular sieve. The specific surface area, pore volume, acidity properties (including total acidity and external surface acidity equivalent), metal content, and external surface metal content of the catalyst are shown in Table 1.

[0089] Example 6

[0090] 1. Catalyst preparation:

[0091] The preparation method is the same as in Example 1, except that the raw material is changed to H-type MWW molecular sieve with a silicon-aluminum molar ratio of 50:1, and the other steps remain unchanged.

[0092] The obtained catalyst XRD pattern is as follows Figure 1 As shown in the figure, XRD analysis reveals that the catalyst retains the overall structure of the MWW molecular sieve. The specific surface area, pore volume, acidity properties (including total acidity and external surface acidity equivalent), metal content, and external surface metal content of the catalyst are shown in Table 1.

[0093] Examples 7-9

[0094] Take 0.25g of the catalyst synthesized in Example 1 and add it to the high-pressure reactor. Then add 10g of benzene to the reactor and charge it with hydrogen gas. The reaction is completed after 4 hours. See Table 2 for specific evaluation conditions and evaluation data.

[0095] Example 10

[0096] 0.25g of the catalyst synthesized in Example 2 was added to a high-pressure reactor, followed by the addition of 10g of benzene and the introduction of hydrogen gas to bring the system pressure to 1.0MPa. The system was then heated to 180°C and the reaction was stopped after 4 hours.

[0097] For ease of comparison, the evaluation data is summarized in Table 2.

[0098] Example 11

[0099] 0.25g of the catalyst synthesized in Example 3 was added to a high-pressure reactor, followed by the addition of 10g of benzene and the introduction of hydrogen gas to bring the system pressure to 1.0MPa. The system was then heated to 180°C and the reaction was stopped after 4 hours.

[0100] For ease of comparison, the evaluation data is summarized in Table 2.

[0101] Example 12

[0102] 0.25g of the catalyst synthesized in Example 4 was added to a high-pressure reactor, followed by the addition of 10g of benzene and the introduction of hydrogen gas to bring the system pressure to 1.0MPa. The system was then heated to 180°C and the reaction was stopped after 4 hours.

[0103] For ease of comparison, the evaluation data is summarized in Table 2.

[0104] Example 13

[0105] 0.25g of the catalyst synthesized in Example 5 was added to a high-pressure reactor, followed by the addition of 10g of benzene and the introduction of hydrogen gas to bring the system pressure to 1.0MPa. The system was then heated to 180°C and the reaction was stopped after 4 hours.

[0106] For ease of comparison, the evaluation data is summarized in Table 2.

[0107] Example 14

[0108] 0.25 g of the catalyst synthesized in Example 6 was added to a high-pressure reactor, followed by the addition of 10 g of benzene and the introduction of hydrogen gas to bring the system pressure to 1.0 MPa. The system was then heated to 180 °C and the reaction was stopped after 4 hours.

[0109] For ease of comparison, the evaluation data is summarized in Table 2.

[0110] Comparative Example 1

[0111] 1. Catalyst preparation:

[0112] The preparation method is the same as in Example 1, except that the treatment with phenyltrimethoxysilane is omitted, and precursor II is directly evaluated as a catalyst.

[0113] 2. Catalyst Evaluation:

[0114] The catalyst evaluation method is described in Example 10.

[0115] For ease of comparison, the evaluation results of the catalysts are listed in Table 2.

[0116] Comparative Example 2

[0117] 1. Catalyst preparation:

[0118] The preparation method is the same as in Example 1, except that the content of ruthenium chloride of the same concentration added is increased to 8 mL, that is, only the metal content in the catalyst is increased.

[0119] 2. Catalyst Evaluation:

[0120] The catalyst evaluation method is described in Example 10.

[0121] For ease of comparison, the evaluation results of the catalysts are listed in Table 2.

[0122] Comparative Example 3

[0123] 1. Catalyst preparation:

[0124] The preparation method is the same as in Example 1, except that the arylation step condition was changed from adding "0.3g phenyltrimethoxysilane" to adding 0.8g phenyltrimethoxysilane.

[0125] 2. Catalyst Evaluation:

[0126] The catalyst evaluation method is described in Example 10.

[0127] For ease of comparison, the evaluation results of the catalysts are listed in Table 2.

[0128] Comparative Example 4

[0129] 1. Catalyst preparation:

[0130] The catalyst prepared in Example 1 was selected.

[0131] 2. Catalyst Evaluation:

[0132] The catalyst evaluation method is described in Example 10, except that the hydrogen partial pressure in the reaction conditions was changed to 4.0 MPa, while the other operations remained unchanged.

[0133] For ease of comparison, the evaluation results of the catalysts are listed in Table 2.

[0134] Table 1. Physicochemical properties of catalysts obtained in each example and comparative example.

[0135]

[0136] Table 2 Catalytic performance of catalysts obtained in each example and comparative example

[0137]

[0138]

[0139] Example 15

[0140] The catalyst prepared in Example 1 was washed, dried, and then added to the next reaction, for a total of 6 cycles. The catalyst was evaluated by adding 8g of benzene to the high-pressure reactor and purging with hydrogen to reach a system pressure of 1.2MPa. The system was then heated to 150°C and the reaction was stopped after 4 hours.

[0141] Table 3

[0142] Number of times to apply in a loop Yield of cyclohexylbenzene (%) Selectivity of cyclohexylbenzene (%) 1 62 94.7 2 61 93.8 3 62 93.5 4 61 94.1 5 60 93.3 6 61 94.0

[0143] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for one-step preparation of cyclohexylbenzene by benzene hydrogenation, comprising a contact reaction between benzene and a catalyst, using hydrogen as a hydrogen source to obtain cyclohexylbenzene; wherein the catalyst comprises a molecular sieve, an active metal M group, and an R group; in, The active metal M is selected from one or more of ruthenium, platinum, palladium, copper, and nickel; the mass content of the active metal M is 0.22% to 1.5% based on the mass of the catalyst. Wherein, the R group is selected from at least one of phenyl, benzyl, and phenethyl; based on the mass of the catalyst, the mass content of the R group is 2% to 20%; The total acid amount of the catalyst is 400-1500 µmol·g -1 The relative acid equivalent of the outer surface of the catalyst is 15%-35%. In the reaction, the hydrogen pressure is 0.8~2.5 MPa.

2. The method according to claim 1, characterized in that, The active metal M is ruthenium or / and palladium.

3. The method according to claim 1, characterized in that, The catalyst contains molecular sieves selected from at least one of MWW, FAU, MOR, BEA, and ATS; the molecular sieves account for 80%-95% of the catalyst mass, and the silicon-aluminum molar ratio is 2-50.

4. The method according to claim 3, characterized in that, The molecular sieve in the catalyst has a silicon-to-aluminum molar ratio of 4 to 40.

5. The method according to claim 1, characterized in that, The specific surface area of the catalyst is 385-500 m 2 / g; the total pore volume of the catalyst is not less than 0.18 cm 3 / g.

6. The method according to claim 1, characterized in that, The specific surface area of the catalyst is 410-490 m 2 / g; the total pore volume of the catalyst is 0.18-1.0 cm 3 / g.

7. The method according to claim 1, characterized in that, The method for preparing the catalyst includes the following steps: (1) Mix the solution containing metal M with H-type molecular sieve precursor I, and then dry and reduce it to obtain precursor II; (2) The precursor II, aryl reagent C and solvent are mixed and reacted, and the catalyst is obtained by filtration, washing and drying.

8. The method according to claim 7, characterized in that, In step (1), the concentration of the solution containing metal M is 1.5~45 g / L.

9. The method according to claim 7, characterized in that, In step (2), the arylating agent c is selected from one or more of phenyltrimethoxysilane, tolyltrimethoxysilane, phenylsilanetriol, tolylsilanetriol, and diphenylsilanediol; the solvent is at least one of ethanol or toluene.

10. The method according to claim 7, characterized in that, In step (2), the mass ratio of the added precursor II, arylating agent c, and solvent is 1:(0.06~0.45):(6~55).

11. The method according to claim 1, characterized in that, In the reaction, the mass ratio of benzene to catalyst is 8-40, the reaction temperature is 100-220℃, and the reaction time is 2-8 hours.

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