Method for preparing cyclohexanol by using X oil

Abstract

The invention relates to the field of X oil recovery, and discloses a method for preparing cyclohexanol by using X oil. The method comprises the following steps: (1) in the presence of hydrogen, introducing a material flow I containing X oil and an organic solvent into a hydrogenation reactor filled with a hydrogenation catalyst, and carrying out a hydrogenation reaction to obtain a material flow II; the organic solvent is an alkane organic solvent of which the boiling point is less than 130 DEG C; (2) the material flow II is introduced into a two-stage rectifying tower for two-stage refining separation, and cyclohexanol is obtained; wherein the X oil is a tower kettle heavy component for refining cyclohexanone prepared by dehydrogenation of cyclohexanol, the X oil contains phenol, the total content of dipolyketone in the X oil is less than or equal to 20wt%, and the content of cyclohexanol is less than or equal to 20wt%. The scheme provided by the invention has the beneficial effects of high phenol conversion rate and high cyclohexanol selectivity, the utilization value of the X oil can be improved, the production cost is reduced, and the product value is improved.

Description

Technical Field

[0001] This invention relates to the field of X oil recovery, and more specifically to a method for preparing cyclohexanol from X oil. Background Technology

[0002] In the production of caprolactam, one method for producing cyclohexanone is called the hydration method. This involves partially hydrogenating benzene to obtain cyclohexene, hydrating cyclohexene to obtain cyclohexanol, and then dehydrogenating it to obtain cyclohexanone. The crude alcohol-ketone obtained after the dehydrogenation reaction is purified to remove light component impurities, followed by distillation to obtain cyclohexanone. The remaining cyclohexanol and heavy component impurities are then further distilled. The cyclohexanol is distilled off at the top of the distillation column, and the remaining heavy component impurities in the bottom of the column are known as X oil.

[0003] X-oil has a complex composition and contains many impurities, making its recycling difficult. Previously, the primary method for treating X-oil was incineration. However, this method causes environmental pollution, and simple incineration has low material utilization rates, easily leading to resource waste. Therefore, developing economical, environmentally friendly, and efficient X-oil recycling technologies is a very meaningful task. This technology can reduce the demand for new raw materials and the cost of waste treatment, lower production and operating costs, improve the environment, and meet the requirements of energy conservation and emission reduction.

[0004] CN105316024A discloses a method for recycling X oil, using commercially available molecular sieves as catalysts to convert X oil into products such as liquefied petroleum gas, gasoline, and diesel through catalytic cracking, with a total yield of useful components reaching 77.4%. However, the reaction temperature is high (400-600℃), requiring a large amount of carrier gas (5-10 times that of the feed gas), and the catalyst is not recycled, resulting in excessive investment and energy consumption.

[0005] CN117209358A discloses a method for recovering waste oil from a cyclohexanol and cyclohexanone process system. This method involves controlling the temperature of a distillation column and altering the top product, then coarsely screening the various components of the X oil to achieve its recovery. However, the X oil contains a large amount of phenol, and cyclohexanol and phenol form an azeotrope, resulting in the recovered cyclohexanol containing numerous impurities, making direct recovery difficult. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing cyclohexanol from the bottom refining component X oil of cyclohexanol dehydrogenation to cyclohexanone purification tower, which has both high feed conversion rate and high cyclohexanol selectivity.

[0007] To achieve the above objectives, the present invention provides a method for preparing cyclohexanol using X oil, the method comprising:

[0008] (1) In the presence of hydrogen, stream I containing X oil and organic solvent is introduced into a hydrogenation reactor packed with hydrogenation catalyst to carry out hydrogenation reaction, and stream II is obtained.

[0009] The organic solvent is an alkane-based organic solvent with a boiling point <130℃;

[0010] (2) The stream II is introduced into a two-stage distillation column for two-stage purification and separation to obtain cyclohexanol;

[0011] The X oil is a refining component from the bottom of the column for the dehydrogenation of cyclohexanone from cyclohexanol. The X oil contains phenol, and the total content of dimer ketone and the content of cyclohexanol in the X oil are ≤20wt%.

[0012] The method for preparing cyclohexanol from X oil provided by this invention has the beneficial effects of high phenol conversion rate and high cyclohexanol selectivity. This method can improve the utilization value of X oil, reduce production costs, and increase product value. Detailed Implementation

[0013] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0014] The C5-C8 alkane organic solvents refer to straight-chain alkanes, branched alkanes, or cycloalkanes with a total of 5-8 carbon atoms (e.g., 5, 6, 7, or 8). Examples include cyclohexane, n-hexane, n-heptane, and cyclopentane.

[0015] As mentioned above, this invention provides a method for preparing cyclohexanol using X oil, the method comprising:

[0016] (1) In the presence of hydrogen, stream I containing X oil and organic solvent is introduced into a hydrogenation reactor packed with hydrogenation catalyst to carry out hydrogenation reaction, and stream II is obtained.

[0017] The organic solvent is an alkane-based organic solvent with a boiling point <130℃;

[0018] (2) The stream II is introduced into a two-stage distillation column for two-stage purification and separation to obtain cyclohexanol;

[0019] The X oil is a refining component from the bottom of the column for the dehydrogenation of cyclohexanone from cyclohexanol. The X oil contains phenol, and the total content of dimer ketone and the content of cyclohexanol in the X oil are ≤20wt%.

[0020] It should be noted that, in this invention, the diketone refers to 2-cyclohexylcyclohexanone and / or cyclohexenylcyclohexanone.

[0021] This invention specifically employs an alkane-based organic solvent mixed with the X oil provided by this invention to form stream I, which can improve hydrogen solubility, increase gas-liquid contact area, enhance gas-liquid-solid mass transfer, dilute reactant concentration, avoid local overheating, weaken intermolecular forces of reactants, promote substrate adsorption to catalyst active sites, reduce deposition of heavy components on catalyst surface, prevent catalyst sintering, thereby further improving phenol conversion and cyclohexanol selectivity, and maintaining excellent catalyst stability.

[0022] According to a preferred embodiment, in step (1), the mass ratio of the X oil to the organic solvent is 1:1-10, preferably 1:1-5, and more preferably 1:1-3.

[0023] According to another preferred embodiment, in step (1), the organic solvent is a C5-C8 alkane organic solvent.

[0024] Preferably, in step (1), the organic solvent is a C5-C7 alkane organic solvent.

[0025] More preferably, in step (1), the organic solvent is selected from at least one of cyclohexane, n-hexane, n-heptane, and cyclopentane.

[0026] According to a preferred embodiment, in step (1), the X oil contains the following components in weight percentage: 42-46 wt% phenol, 15-16 wt% cyclohexanol, 7-10 wt% diketone, and 2-3 wt% cyclohexanone.

[0027] In this invention, the components of the X oil may further include 25-30 wt% of other impurities; the other impurities refer to substances other than phenol, cyclohexanol, diketone, and cyclohexanone. For example, the other impurities include 2-cyclohexenol, 1-n-propylcyclohexanol, and cyclohexyl hexanoate.

[0028] In this invention, the dimerketone exhibits strong adsorption on the catalyst surface, covering active sites and affecting the adsorption of phenol and hydrogen, thereby impacting catalytic activity. Furthermore, the ketone groups in the dimerketone may be catalytically hydrogenated to form alcohols. If the hydrogen partial pressure is insufficient, incomplete hydrogenation of phenol may occur, leading to the accumulation of by-products. The inventors discovered that when the total content of dimerketone in the X oil is ≤20wt%, preferably ≤15wt%, more preferably ≤10wt%; and the content of cyclohexanol is ≤20wt%, preferably ≤16wt%, it can reduce liquid phase viscosity, increase hydrogen solubility, optimize mass transfer efficiency, reduce side reactions, enhance reaction selectivity and product yield, reduce local overheating, and improve catalyst stability and lifespan.

[0029] According to another preferred embodiment, in step (1), the hydrogenation catalyst includes an active component and a support, wherein the active component contains at least one element selected from Ni, Pd, Pt, Ru, and Rh.

[0030] Preferably, the active component is selected from at least one of Ni, Pd, and Pt.

[0031] In a preferred embodiment, in step (1), the active component, calculated by element, accounts for 5-40 wt% of the total mass of the hydrogenation catalyst, preferably 10-30 wt%, and more preferably 15-25 wt%.

[0032] According to a preferred embodiment, in step (1), the hydrogenation reactor is a fixed-bed reactor.

[0033] According to another preferred embodiment, in step (1), the conditions for the hydrogenation reaction include: a temperature of 130-200℃, preferably 135-180℃; a pressure of 0.8-2MPa, preferably 0.9-1.6MPa; and a mass hourly space velocity of 1.2-36 mL h⁻¹. -1 g cat -1 Preferably 2.4-30 mL h -1 g cat -1 More preferably 3.6-24 mL h -1 g cat -1 .

[0034] In a preferred embodiment, in step (1), the amount of hydrogen used in the hydrogenation reaction satisfies the following: the hydrogen-to-oil ratio is 60-240:1, preferably 80-180:1, and more preferably 100-140:1.

[0035] In this invention, the hydrogen-to-oil ratio refers to the ratio of the amount of hydrogen to the volume of X oil in the hydrogenation reaction.

[0036] In a preferred embodiment, in step (1), the conditions for the hydrogenation reaction further include a feed rate of 0.1-3 mL / min, preferably 0.2-2 mL / min.

[0037] According to a preferred embodiment, in step (2), the two-stage purification separation includes: performing a first purification separation in a first-stage distillation column and performing a second purification separation in a second-stage distillation column.

[0038] In a preferred embodiment, the conditions for the first purification separation include: a bottom temperature of 80-100°C, preferably 85-95°C; a top temperature of 30-50°C, preferably 38-45°C; and a vacuum degree of 20-60 kPa, preferably 30-53 kPa.

[0039] In a preferred embodiment, the conditions for the second purification separation include: a bottom temperature of 110-140°C, preferably 115-130°C; a top temperature of 70-110°C, preferably 80-95°C; and a vacuum degree of 2-15 kPa, preferably 5-10 kPa.

[0040] According to another preferred embodiment, in step (2), the reflux ratio of the two-stage refining separation is 4-8:1, preferably 4-6:1.

[0041] It should be noted that the reflux ratio of the first-stage purification separation refers to the ratio of the reflux liquid flow rate returning to the column from the top of the distillation column to the product flow rate containing organic solvents; the reflux ratio of the second-stage purification separation refers to the ratio of the reflux liquid flow rate returning to the column from the top of the distillation column to the product flow rate containing cyclohexanol.

[0042] In this invention, a self-made hydrogenation catalyst or a commercially available one can be used. However, in order to further improve the conversion rate of phenol in X oil and the selectivity of the product cyclohexanol, this invention preferably uses a hydrogenation catalyst obtained by the following method to carry out the hydrogenation reaction.

[0043] According to a preferred embodiment, in step (1), the hydrogenation catalyst is prepared by an operation comprising the following steps:

[0044] S1: The active component precursor and the support are ball-milled to obtain mixture I; the active component precursor is selected from at least one of metal-sourced hydrochloride, metal-sourced nitrate and metal-sourced carbonate; the metal source is selected from at least one of Ni, Pd, Pt, Ru and Rh.

[0045] S2: The mixture I is calcined in the presence of an inert atmosphere to obtain the hydrogenation catalyst.

[0046] More preferably, in step S1, the active component precursor is Pd hydrochloride or Ni hydrochloride.

[0047] In a preferred embodiment, in step S1, the support is selected from at least one of SiO2, TiO2, Al2O3, activated carbon, metal-organic framework materials and carbon nitride materials, preferably Al2O3 and / or activated carbon.

[0048] According to a preferred embodiment, in step S1, the conditions for ball milling include: a rotation speed of 300-600 r / min, preferably 400-500 r / min; and a time of 4-8 h, preferably 5-7 h.

[0049] It should be noted that, in this invention, the average particle size refers to the average diameter of the particles.

[0050] According to a particularly preferred embodiment, in step S1, the mixture I is obtained by ball milling at a rotation speed of 300-600 r / min for 8-12 hours in the presence of 50 grinding balls with a diameter of 4-8 mm and 20 grinding balls with a diameter of 9-12 mm. The invention will not be described in detail here, and those skilled in the art should not construe it as a limitation of the invention.

[0051] According to another preferred embodiment, in step S2, the calcination temperature is 400-600℃, preferably 400-500℃; and the time is 3-6h, preferably 4-5h.

[0052] In a preferred embodiment, the method described in step S2 of the present invention may further include: removing impurities from the intermediate product obtained by the calcination treatment to obtain the hydrogenation catalyst.

[0053] The present invention does not impose any particular limitation on the specific method of impurity removal. Those skilled in the art can select methods based on known techniques. For example, the intermediate product obtained from calcination is centrifuged and washed 3-6 times, and then dried at 60-120°C to obtain the hydrogenation catalyst. The present invention will not be described in detail here, and those skilled in the art should not construe this as a limitation of the present invention.

[0054] In a preferred embodiment, the method further includes: before performing step (1), the X oil is subjected to solid-liquid separation treatment to remove solid impurities therein.

[0055] This invention does not impose any particular limitation on the specific method of solid-liquid separation treatment. Those skilled in the art can select appropriate methods based on known techniques. For example, X oil can be filtered to remove solid impurities, yielding X oil filtrate. This invention will not be described in detail here, and those skilled in the art should not construe this as a limitation of the invention.

[0056] The present invention does not have any special requirements on the temperature of the filtration. For example, it can be carried out at room temperature (15-30°C).

[0057] In a preferred embodiment of the present invention, the method further includes reducing the hydrogenation catalyst before carrying out the hydrogenation reaction, wherein the conditions for the reduction treatment include a temperature of 300-600°C and a time of 4-6 hours.

[0058] In preferred cases, the phenol conversion rate of the method is ≥92.0%, preferably ≥97.0%; and the selectivity of cyclohexanol is ≥94.0%, preferably ≥96.5%.

[0059] The present invention will be described in detail below through examples. Where specific experimental steps or conditions are not specified in the following examples, they can be performed according to the known experimental steps or conditions described in the literature in this field. Where the manufacturers of the raw materials or instruments used are not specified, they are all commercially available.

[0060] In the following examples, the content of the active component in the total mass of the hydrogenation catalyst refers to the active component on an elemental basis.

[0061] Composition of Oil X 1: 45.8 wt% phenol, 15.1 wt% cyclohexanol, 8.2 wt% diketone, 2.3 wt% cyclohexanone, and 28.6 wt% other impurities.

[0062] Composition of Oil X 2: 41.0 wt% phenol, 14.6 wt% cyclohexanol, 18.4 wt% diketone, 1.4 wt% cyclohexanone, and 24.6 wt% other impurities.

[0063] Composition of X Oil 3: 30.5 wt% phenol, 28.3 wt% cyclohexanol, 21.2 wt% diketone, 2.2 wt% cyclohexanone, and 17.8 wt% other impurities.

[0064] The room temperature in the following examples is 25±3℃.

[0065] Preparation Example 1

[0066] S1: Weigh 10g of Al2O3 and 8.72g of Ni(NO3)2 using an analytical balance, grind them evenly in a mortar, and then place them in a 100mL ball mill jar. In the presence of 50 grinding balls with a diameter of 6mm and 20 grinding balls with a diameter of 10mm, ball mill at a speed of 400r / min for 10h to obtain mixture I;

[0067] S2: Place mixture I in a sealed tube furnace purged with nitrogen and calcine at 400°C for 4 hours. After cooling to room temperature, remove the mixture, centrifuge and wash it four times, and dry it at 90°C to obtain hydrogenation catalyst I (the active component accounts for 21.8 wt% of the total mass of hydrogenation catalyst I).

[0068] Preparation Example 2

[0069] The preparation was carried out using a method similar to that of Example 1, except that the active component precursor in step S1 was 8.42 g of H2PtCl6, to obtain hydrogenation catalyst II (the active component accounted for 23.2 wt% of the total mass of hydrogenation catalyst II).

[0070] Preparation Example 3

[0071] The preparation was carried out using a method similar to that of Example 1, except that the support in step S1 was 10 g of zirconium oxide, resulting in hydrogenation catalyst III (the active component accounted for 21.3 wt% of the total mass of hydrogenation catalyst III).

[0072] Preparation Example 4

[0073] The preparation was carried out using a method similar to that of Example 1, except that the calcination time in step S2 was 5 h, to obtain hydrogenation catalyst IV (the active component accounted for 20.2 wt% of the total mass of hydrogenation catalyst IV).

[0074] Example 1

[0075] (1) 720g of X oil 1 was filtered at room temperature to remove solid impurities. The filtrate was mixed with cyclohexane at a mass ratio of 1:2 to form a solution. The solution was introduced into the middle section of a fixed-bed reactor containing 15g of hydrogenation catalyst I. Quartz sand was packed at both ends for fixation. Nitrogen gas was introduced to check for leaks in the reactor. Then, hydrogen gas was used to replace the nitrogen gas in the reaction system. The temperature was raised to 550℃ in the presence of hydrogen gas and maintained for 5h to reduce the catalyst. After the reduction was completed and the temperature was lowered to room temperature, hydrogen gas was introduced at a hydrogen-to-oil ratio of 120:1. The pressure was increased to 1.5MPa, the reactor temperature was raised to 140℃, and the mass hourly space velocity was 6mL / h. -1 g cat -1 The filtrate flow rate was 1.5 mL / min, and hydrogenation was carried out to obtain stream II;

[0076] (2) The collected stream is introduced into the distillation column for distillation. The bottom temperature of the first-stage distillation column is 90℃, the top temperature is 40℃, the vacuum degree is 40kPa, and the reflux ratio is 4:1. The bottom product is collected for secondary distillation. The bottom temperature of the second-stage distillation column is 130℃, the top temperature is 90℃, the vacuum degree is 8kPa, and the reflux ratio is 4:1. The top fraction is collected and named XL-1.

[0077] Example 2

[0078] The process was carried out using a method similar to that in Example 1, except that hydrogenation catalyst I in step (1) was replaced with hydrogenation catalyst II of equal mass, and the reduction conditions were adjusted to a hydrogen atmosphere and heated to 300°C, and maintained for 5 hours to reduce the catalyst, resulting in a fraction named XL-2.

[0079] Example 3

[0080] The procedure was carried out using a method similar to that in Example 1, except that hydrogenation catalyst I in step (1) was replaced with an equal mass of hydrogenation catalyst III, while keeping the reduction conditions unchanged, and a fraction was obtained, named XL-3.

[0081] Example 4

[0082] The procedure was carried out using a method similar to that in Example 1, except that hydrogenation catalyst I in step (1) was replaced with an equal mass of hydrogenation catalyst IV, while keeping the reduction conditions unchanged, and a fraction was obtained, named XL-4.

[0083] Example 5

[0084] The same method as in Example 1 was used, except that the hydrogen-to-oil ratio was kept constant, the hydrogen in step (1) was pressurized to 2 MPa, and other conditions were kept constant to obtain a fraction named XL-5.

[0085] Example 6

[0086] The process was carried out using a method similar to that in Example 1, except that the reactor in step (1) was heated to 180°C while keeping other conditions unchanged, and a fraction was obtained, which was named XL-6.

[0087] Example 7

[0088] The same method as in Example 1 was used, except that in step (1), the amount of filtrate was kept constant, the mass ratio of filtrate to cyclohexane was adjusted to 1:5, and other conditions were kept constant to obtain a fraction named XL-8.

[0089] Example 8

[0090] The same method as in Example 1 was used, except that the cyclohexane in step (1) was replaced with an equal mass of cyclobutane, while keeping other conditions unchanged, and a fraction was obtained, named XL-7.

[0091] Example 9

[0092] The same method as in Example 1 was used, except that X oil 1 in step (1) was replaced with an equal mass of X oil 2, while keeping other conditions unchanged, and a fraction was obtained, named XL-9.

[0093] Example 10

[0094] The same method as in Example 1 was used, except that in step (1), the amount of filtrate was kept constant, the mass ratio of filtrate to cyclohexane was adjusted to 1:10, and other conditions were kept constant to obtain a fraction named XL-10.

[0095] Comparative Example 1

[0096] The procedure was carried out using a method similar to that of Example 1, except that no organic solvent was used in step (1);

[0097] Specifically, in step (1), 720g of X oil 1 is filtered at room temperature to remove solid impurities and obtain filtrate. The filtrate is introduced into the middle section of a fixed-bed reactor containing 15g of hydrogenation catalyst I. Quartz sand is packed at both ends for fixation. Nitrogen gas is introduced to check for leaks in the reactor. Then, hydrogen gas is used to replace the nitrogen gas in the reaction system. The temperature is raised to 550℃ in the presence of hydrogen gas and maintained for 5h to reduce the catalyst. After the reduction is completed and the temperature is lowered to room temperature, hydrogen gas is introduced at a hydrogen-to-oil ratio of 120:1. The hydrogen gas is pressurized to 1.5MPa, the reactor temperature is raised to 140℃, and the mass hourly space velocity is 6mL / h. -1 g cat -1 The filtrate flow rate was 1.5 mL / min, and hydrogenation was carried out to obtain stream II;

[0098] Step (2) is the same as in Example 1, and a fraction is obtained, named XD-1.

[0099] Comparative Example 2

[0100] The same method as in Example 1 was used, except that the cyclohexane in step (1) was replaced with an equal mass of cyclohexanol, while keeping the other conditions unchanged, and a fraction was obtained, named XD-2.

[0101] Comparative Example 3

[0102] The same method as in Example 1 was used, except that X oil 1 in step (1) was replaced with an equal mass of X oil 3, while keeping the other conditions unchanged, and a fraction was obtained, named XD-3.

[0103] Test case

[0104] The fractions obtained in the above examples were analyzed and detected using an Agilent gas chromatograph equipped with an INNOWAX capillary column. The area normalization method was used for quantitative analysis of each component.

[0105] Phenol conversion rate = (mass content of phenol in X oil - mass content of phenol in stream II) / mass content of phenol in X oil × 100%.

[0106] Cyclohexanol selectivity = [(mass content of cyclohexanol in stream II - mass content of cyclohexanol in X oil) × 94.11] / [(mass content of phenol in X oil - mass content of phenol in stream II) × 100.16] × 100%.

[0107] The results are shown in Table 1.

[0108] Table 1

[0109] Example number distillate The phenol conversion rate is (%) Cyclohexanol selectivity (%) Example 1 XL-1 99.2 99.7 Example 2 XL-2 98.1 96.5 Example 3 XL-3 98.3 99.2 Example 4 XL-4 97.3 99.3 Example 5 XL-5 100.0 99.7 Example 6 XL-6 99.9 99.6 Example 7 XL-7 99.7 99.5 Example 8 XL-8 93.6 97.2 Example 9 XL-9 96.2 94.1 Example 10 XL-10 92.3 99.5 Comparative Example 1 XD-1 20.3 65.1 Comparative Example 2 XD-2 41.5 98.2 Comparative Example 3 XD-3 61.1 91.7

[0110] As can be seen from the results in Table 1, the method for preparing cyclohexanol using the bottom refining component X oil from the dehydrogenation of cyclohexanol to cyclohexanone in this invention has a higher phenol conversion rate and cyclohexanol selectivity than the prior art, which significantly improves the utilization value of X oil and reduces production costs.

[0111] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing cyclohexanol using X oil, characterized in that, The method includes: (1) In the presence of hydrogen, stream I containing X oil and organic solvent is introduced into a hydrogenation reactor packed with hydrogenation catalyst to carry out hydrogenation reaction, and stream II is obtained. The organic solvent is an alkane-based organic solvent with a boiling point <130℃; (2) The stream II is introduced into a two-stage distillation column for two-stage purification and separation to obtain cyclohexanol; The X oil is a refining component from the bottom of the column for the dehydrogenation of cyclohexanone from cyclohexanol. The X oil contains phenol, and the total content of dimer ketone and the content of cyclohexanol in the X oil are ≤20wt%.

2. The method according to claim 1, characterized in that, In step (1), the mass ratio of the X oil to the organic solvent is 1:1-10, preferably 1:1-5; And / or, the organic solvent is a C5-C8 alkane organic solvent.

3. The method according to claim 1 or 2, characterized in that, In step (1), the X oil contains the following components in weight percentage: 42-46 wt% phenol, 15-16 wt% cyclohexanol, 7-10 wt% diketone, and 2-3 wt% cyclohexanone.

4. The method according to any one of claims 1-3, characterized in that, In step (1), the hydrogenation catalyst includes an active component and a support, wherein the active component contains at least one element selected from Ni, Pd, Pt, Ru, and Rh; And / or, the active component, by elemental basis, accounts for 5-40 wt% of the total mass of the hydrogenation catalyst.

5. The method according to any one of claims 1-4, characterized in that, In step (1), the hydrogenation reactor is a fixed-bed reactor.

6. The method according to any one of claims 1-5, characterized in that, In step (1), the conditions for the hydrogenation reaction include: a temperature of 130-200℃, a pressure of 0.8-2 MPa, and a mass hourly space velocity of 1.2-36 mL h⁻¹. -1 g cat -1 ; And / or, the amount of hydrogen used in the hydrogenation reaction satisfies the following: hydrogen-to-oil ratio of 60-240:

1.

7. The method according to any one of claims 1-6, characterized in that, In step (2), the two-stage purification separation operation includes: performing a first purification separation in a first-stage distillation column and a second purification separation in a second-stage distillation column; The conditions for the first purification and separation include: a bottom temperature of 80-110℃, a top temperature of 30-50℃, and a vacuum degree of 20-60kPa; And / or, the conditions for the second purification separation include: a bottom temperature of 110-140°C, a top temperature of 70-110°C, and a vacuum of 2-15 kPa.

8. The method according to claim 7, characterized in that, The reflux ratios of the first purification separation and the second purification separation are each independently 4-8:

1.

9. The method according to claim 4, characterized in that, In step (1), the hydrogenation catalyst is prepared by an operation comprising the following steps: S1: The active component precursor and the support are ball-milled to obtain mixture I; the active component precursor is selected from at least one of metal-sourced hydrochloride, metal-sourced nitrate and metal-sourced carbonate; the metal source is selected from at least one of Ni, Pd, Pt, Ru and Rh. S2: The mixture I is calcined in the presence of an inert atmosphere to obtain the hydrogenation catalyst.

10. The method according to claim 9, characterized in that, In step S1, the conditions for ball milling include: a rotation speed of 300-600 r / min and a time of 8-12 h; And / or, in step S2, the calcination treatment is carried out at a temperature of 400-600°C for a time of 3-6 hours; And / or, the phenol conversion rate of the method is ≥92.0%, and the selectivity of cyclohexanol is ≥94.0%.