Catalyst for partial hydrogenation of benzene, preparation method thereof and method for preparing cyclohexene by using catalyst

Abstract

The present invention relates to a catalyst for partial hydrogenation of benzene, a method for preparing the same, and a method for preparing cyclohexene using the same. The catalyst for partial hydrogenation of benzene takes oxidized fullerene as a catalyst carrier, takes ruthenium as a main catalyst, and further comprises one or more auxiliaries. The preparation method of the benzene partial hydrogenation catalyst taking the oxidized fullerene as the carrier is simple and easy to control, and the catalyst also has high activity, high selectivity and good stability, can greatly reduce the production cost of cyclohexene prepared by benzene partial hydrogenation, and has very important economic significance for industrial production of cyclohexene.

Description

Technical Field

[0001] The present invention relates to the field of fine chemicals, and particularly relates to a ruthenium-based catalyst for the partial hydrogenation of benzene to cyclohexene, a preparation method thereof, and a method for preparing cyclohexene using the same. Background Art

[0002] As a very important organic chemical raw material, cyclohexene is widely used in the synthesis of chemical products such as adipic acid, caprolactam, cyclohexanol, nylon 6, and nylon 66. However, compared with the partial hydrogenation of benzene to cyclohexene, the complete hydrogenation of benzene to cyclohexane is a thermodynamically more favorable reaction. Therefore, developing a catalyst with high conversion and high selectivity is the key to realizing the partial hydrogenation of benzene.

[0003] Currently, commonly used catalysts for the partial hydrogenation of benzene include ruthenium-based catalysts, nickel-based catalysts, palladium-based catalysts, etc. Among them, ruthenium-based catalysts have attracted much attention due to their high activity and selectivity, but there are still the following problems: 1) Ruthenium nanoparticles are prone to agglomeration during the reaction process, resulting in a decrease in catalytic activity; 2) The selectivity of the partial hydrogenation of benzene to cyclohexene is relatively low, and side product cyclohexane is easily generated; 3) Traditional catalyst support materials (such as activated carbon, alumina, titanium dioxide, and diatomite, etc.) have a limited specific surface area and insufficient chemical stability, making it difficult to meet the requirements of high-performance catalysts. In order to improve the activity and stability of the catalyst, it is crucial to find a support with a large specific surface area and good stability.

[0004] In order to improve the stability of the catalyst, benzene conversion, and cyclohexene selectivity, it is necessary to select a suitable support to improve the overall performance of the catalyst. As a new type of spherical carbon material, oxidized fullerene has the following characteristics: 1) The high specific surface area of oxidized fullerene can provide abundant active sites for the catalyst; 2) The surface of oxidized fullerene contains functional groups such as hydroxyl groups and carboxyl groups, which can significantly enhance the dispersion and stability of metal catalysts; 3) The electronic structure of oxidized fullerene can adjust the activity and selectivity of the catalyst, improving the reaction efficiency; 4) Oxidized fullerene exhibits excellent chemical stability under conditions such as high temperature and strong acids and bases, and is suitable as a catalyst support.

[0005] In order to reduce the catalyst cost, improve the catalytic activity, overcome the defects that the existing catalysts for the preparation of cyclohexene by the partial hydrogenation of benzene have limited improvement in benzene conversion and cyclohexene selectivity, and it is difficult to maintain high cyclohexene selectivity at high benzene conversion, poor resistance to process fluctuations, large usage amount, and poor stability, it is necessary to provide a simple and feasible ruthenium-based catalyst for the partial hydrogenation of benzene to cyclohexene with high catalytic activity, high benzene conversion, and cyclohexene selectivity, a preparation method thereof, and an application. Summary of the Invention

[0006] The object of the present invention is to provide a benzene partial hydrogenation catalyst with high activity, high selectivity and high stability. A multi-component catalyst with ruthenium as the main catalyst and additives is loaded on oxidized fullerene. By utilizing the spherical structure, high specific surface area and surface oxygen-containing functional groups of oxidized fullerene, which can significantly improve the dispersibility and stability of the catalyst, the problems of easy agglomeration, low selectivity, large usage amount and poor stability of the existing catalyst are solved.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A catalyst for benzene partial hydrogenation, characterized in that the catalyst uses oxidized fullerene as the catalyst carrier, ruthenium as the main catalyst, and also contains one or more additives;

[0009] Preferably, the oxidized fullerene is selected from one or more of oxidized C60, C70, C76, C84, C90, C94, C98 and C100, and preferably oxidized C60;

[0010] Preferably, based on the mass of ruthenium, the main catalyst accounts for 1% to 30% of the mass of the catalyst carrier, and preferably 10%;

[0011] Preferably, the additives are selected from one or more of zinc, aluminum, boron, lanthanum, cerium, iron, copper, cobalt, and magnesium, and preferably zinc and cobalt;

[0012] Preferably, based on the mass of the metal, the mass ratio of the main catalyst to the additives is 1:(2 to 40); more preferably, the additives are zinc and cobalt, and based on the mass of the metal, the mass ratio of ruthenium, zinc and cobalt is 1:(1 to 20):(1 to 20), and more preferably 1:5:5.

[0013] According to another aspect of the present invention, it provides a method for preparing the catalyst, and the method includes the following steps:

[0014] Step 1: Oxidize the fullerene using ozone, air, oxygen or hydrogen peroxide, preferably oxidize the fullerene using ozone, to obtain oxidized fullerene as the catalyst carrier;

[0015] Step 2: Load the ruthenium and additives on the oxidized fullerene to obtain the catalyst for benzene partial hydrogenation.

[0016] According to an embodiment of the present invention, wherein the step 1 includes:

[0017] Step 1a: Disperse the fullerene in a solvent, then introduce ozone at 0°C to 25°C, after reacting for 0.5 - 2 h, raise the temperature to 25°C to 100°C at a rate of 0.5 - 5°C / min and react for 1 - 10 h to obtain an intermediate;

[0018] Step 1b: Add a reducing agent to the intermediate obtained in Step 1a, react at a temperature of 25°C to 100°C for 1 to 12 hours, and then obtain oxidized fullerene by centrifugation, separation, and drying to serve as a catalyst support.

[0019] Preferably, in the above Step 1a, the molar ratio of ozone to fullerene is selected from 3:1 - 30:1, preferably 6:1.

[0020] Preferably, in the above Step 1a, ozone is first introduced at 0°C, and after reacting for 1.5 h, the temperature is raised to 60°C at a rate of 1°C / min and reacted for 5 h to obtain an intermediate.

[0021] Preferably, in the above Step 1b, the added reducing agent is selected from one or more of dimethyl sulfide, triphenylphosphine, sodium sulfite, and zinc powder, preferably dimethyl sulfide.

[0022] Preferably, in the above Step 1b, the molar ratio of the reducing agent to ozone in Step 1a is 1:1 to 1:5, preferably 1:2 to 1:3.

[0023] Preferably, the reaction temperature in the above Step 1b is 50°C.

[0024] Preferably, the reaction time in the above Step 1b is 4 h.

[0025] According to an embodiment of the present invention, wherein, Step 2 includes:

[0026] Step 2a: Immerse the oxidized fullerene prepared in Step 1 in an aqueous solution of precursors of ruthenium and promoters, perform ultrasonic stirring treatment, filter and dry, and reduce the obtained solid under a hydrogen atmosphere to obtain the catalyst for partial hydrogenation of benzene.

[0027] Preferably, the precursor of ruthenium is selected from one or two of ruthenium trichloride, ruthenium nitrate, ruthenium acetate, potassium hexachlororuthenate, potassium hexacyanoruthenate, potassium ruthenate, and ruthenium tribromide, preferably ruthenium trichloride.

[0028] Preferably, the main catalyst accounts for 1% to 30% of the mass of the catalyst support, preferably 10%.

[0029] Preferably, the promoters are mainly selected from one or more of zinc, aluminum, boron, lanthanum, cerium, iron, copper, cobalt, magnesium, etc., preferably zinc and cobalt.

[0030] Preferably, the precursor of the promoter is selected from one or more of the sulfate, acetate, halide, and nitrate of the promoter.

[0031] Preferably, the precursor of zinc is selected from one or more of zinc sulfate, zinc chloride, zinc acetate, and zinc nitrate, preferably zinc sulfate.

[0032] Preferably, the cobalt precursor is selected from one or more of cobalt sulfate, cobalt fluoride, cobalt chloride, cobalt bromide, cobalt iodide, cobalt nitrate, cobalt carbonate, and cobalt acetate, and preferably cobalt chloride;

[0033] Preferably, based on the mass of the metal, the mass ratio of the main catalyst to the promoter is 1:(2 to 40); more preferably, the promoter is zinc and cobalt, and based on the mass of the metal, the mass ratios of ruthenium, zinc, and cobalt to the catalyst mass are selected from 1:(1 to 20):(1 to 20), preferably 1:5:5;

[0034] Preferably, in the step 2a, the ultrasonic stirring treatment time of the oxidized fullerene in the aqueous solution of the precursors of the main catalyst and the promoter is 1 h to 24 h, preferably 12 h;

[0035] Preferably, in the step 2a, the hydrogen pressure is 1 MPa to 5 MPa, preferably 4 MPa;

[0036] Preferably, in the step 2a, the temperature is 100 °C to 200 °C, preferably 130 °C;

[0037] Preferably, in the step 2a, the reduction time in the hydrogen atmosphere is 6 h to 30 h, preferably 20 h.

[0038] According to another aspect of the present invention, it provides a method for preparing cyclohexene using the catalyst, and the method includes the following steps:

[0039] Step 1: Mix the catalyst for partial hydrogenation of benzene described above with benzene and react in a hydrogen atmosphere to obtain cyclohexene.

[0040] Preferably, the catalyst for partial hydrogenation of benzene accounts for 1% to 40% of the mass of benzene, preferably 10%;

[0041] Preferably, the molar ratio of benzene to hydrogen is 1:1 to 1:6, preferably 1:2.2;

[0042] Preferably, the reaction pressure is 3 MPa - 6 MPa, preferably 4.5 MPa;

[0043] Preferably, the reaction temperature is 120 °C - 180 °C, preferably 150 °C;

[0044] Preferably, the reaction time is 10 min to 90 min, preferably 30 min.

[0045] Beneficial effects

[0046] By loading a ruthenium-zinc-cobalt multi-component catalyst on oxidized fullerene, the present invention solves the problems of easy agglomeration and low selectivity of existing catalysts; the high specific surface area and surface oxygen-containing functional groups of oxidized fullerene can significantly improve the dispersibility and stability of the catalyst, while the synergistic effect of the ruthenium-zinc-aluminum multi-component catalyst can further improve the activity and selectivity of the catalyst; the catalyst preparation process is simple, the reaction conditions are mild, easy to control, and the operation is simple, which is suitable for industrial production.

[0047] In summary, the method for preparing a benzene partial hydrogenation catalyst using oxidized fullerene as a carrier provided by the present invention is simple and easy to control, and the catalyst also has high activity, high selectivity and good stability, which can greatly reduce the production cost of benzene partial hydrogenation to cyclohexene, and this has very important economic significance for the industrial production of cyclohexene. Detailed implementation manners

[0048] The present invention has been described in detail above, but the above embodiments are essentially illustrative only and are not intended to limit the present invention. In addition, the present application is not limited by any theory described in the foregoing prior art or the invention content or the following examples.

[0049] Unless otherwise clearly stated, the numerical ranges in the entire application document include any sub-ranges therein and any numerical values incremented by the smallest sub-unit of the given value therein. Unless otherwise clearly stated, the numerical values in the entire application document represent an approximate measure or limitation of the scope of embodiments including minor deviations from the given values and having approximately the mentioned values and having the exact values mentioned. Except for the working examples provided at the end of the detailed description, all numerical values of the parameters (such as quantities or conditions) in this application document (including the appended claims) should be understood to be modified by the term "about" in all cases, whether or not "about" actually appears before the numerical value. "About" means that the stated numerical value allows for a slight imprecision (somewhat close to the exact value; approximately or reasonably close to the value; approximate). If the imprecision provided by "about" is not understood in this ordinary meaning in the art, then "about" as used herein at least represents the variation that can be produced by the ordinary methods of measuring and using these parameters. For example, "about" can include variations of less than or equal to 10%, less than or equal to 5%, less than or equal to 4%, less than or equal to 3%, less than or equal to 2%, less than or equal to 1% or less than or equal to 0.5%.

[0050] The following further illustrates the present invention in conjunction with embodiments. It should be noted that the following embodiments are provided for illustrative purposes only and do not constitute a limitation on the scope of the present invention claimed.

[0051] Unless otherwise specified, the raw materials, reagents, methods, etc. used in the embodiments are all conventional raw materials, reagents, methods in the art.

[0052] Example 1:

[0053] Step 1: Weigh 3.6 g (0.5 mmol) of C60 and disperse it in 500 mL of toluene solution, then place it in an ice-water bath and cool it to 0 °C. Subsequently, slowly introduce 3 mmol of ozone into the above solution and react for 1.5 h. Then, raise the temperature of the reaction solution to 60 °C at a rate of 1 °C / min and react for another 5 h. After TLC detection, the ozone reaction is complete;

[0054] Step 2: Weigh dimethyl sulfide with half the molar amount of ozone and add it to the reaction solution in Step 1. Then, react at 50 °C for 4 h. Subsequently, let the obtained reaction solution stand, centrifuge, and filter to obtain a filter cake. Wash the obtained filter cake with toluene and dry it under vacuum to obtain oxidized C60.

[0055] Step 3: Calculate by mass percentage of oxidized C60, weigh ruthenium trichloride trihydrate (ruthenium content accounts for 37%), zinc sulfate (zinc content accounts for 40.5%), and cobalt chloride (cobalt content accounts for 45.4%) at a ratio of ruthenium accounting for 1%, zinc accounting for 5%, and cobalt accounting for 5%, and dissolve them in water. Then, add the oxidized C60 prepared in Step 2, stir well for 12 h under ultrasonic conditions, then transfer the aqueous solution to a reaction kettle, and reduce it at 130 °C under a hydrogen atmosphere (4 MPa) for 20 h. After cooling, filter the obtained precipitate and freeze-dry it to obtain the ruthenium-based benzene partial hydrogenation catalyst 1.

[0056] Example 2:

[0057] Step 1: Weigh 3.6 g (0.5 mmol) of C60 and disperse it in 500 mL of toluene solution, then place it in an ice-water bath and cool it to 0 °C. Subsequently, slowly introduce 3 mmol of ozone into the above solution and react for 1.5 h. Then, raise the temperature of the reaction solution to 60 °C at a rate of 1 °C / min and react for another 5 h. After TLC detection, the ozone reaction is complete;

[0058] Step 2: Weigh dimethyl sulfide with half the molar amount of ozone and add it to the reaction solution in Step 1. Then, react at 50 °C for 4 h. Subsequently, let the obtained reaction solution stand, centrifuge, and filter to obtain a filter cake. Wash the obtained filter cake with toluene and dry it under vacuum to obtain oxidized C60.

[0059] Step 3: Weigh ruthenium trichloride hydrate (ruthenium content: 37%), zinc sulfate (zinc content: 40.5%), and cobalt chloride (cobalt content: 45.4%) in proportions of 10% ruthenium, 50% zinc, and 50% cobalt by mass percentage of oxidized C60, dissolve them in water, then add the oxidized C60 prepared in Step 2, stir well for 12 h under ultrasonic conditions, then transfer the aqueous solution to a reaction kettle, and reduce it at 130 °C under a hydrogen atmosphere (4 MPa) for 20 h. After cooling, filter the obtained precipitate and freeze-dry it to obtain the ruthenium-based benzene partial hydrogenation catalyst 2.

[0060] Example 3:

[0061] Step 1: Weigh 3.6 g (0.5 mmol) of C60 and disperse it in 500 mL of toluene solution, then cool it to 0 °C in an ice-water bath. Subsequently, slowly introduce 3.0 mmol of ozone into the above solution and react for 1.5 h. Then, raise the temperature of the reaction solution to 50 °C at a rate of 1 °C / min and react for another 5 h. After TLC detection, the ozone reaction is complete.

[0062] Step 2: Weigh dimethyl sulfide with half the molar amount of ozone and add it to the reaction solution in Step 1. Then, react at 50 °C for 4 h. Subsequently, let the obtained reaction solution stand, centrifuge, and filter to obtain a filter cake. Wash the obtained filter cake with toluene and vacuum-dry it to obtain oxidized C60.

[0063] Step 3: Weigh ruthenium trichloride hydrate (ruthenium content: 37%), zinc sulfate (zinc content: 40.5%), and cobalt chloride (cobalt content: 45.4%) in proportions of 30% ruthenium, 150% zinc, and 150% cobalt by mass percentage of oxidized C60, dissolve them in water, then add the oxidized C60 prepared in Step 2, stir well for 12 h under ultrasonic conditions, then transfer the aqueous solution to a reaction kettle, and reduce it at 130 °C under a hydrogen atmosphere (4 MPa) for 20 h. After cooling, filter the obtained precipitate and freeze-dry it to obtain the ruthenium-based benzene partial hydrogenation catalyst 3.

[0064] Comparative Example 1:

[0065] Weigh a certain amount of C60, then weigh ruthenium trichloride hydrate (ruthenium content: 37%), zinc sulfate (zinc content: 40.5%), and cobalt chloride (cobalt content: 45.4%) in proportions of 1% ruthenium, 5% zinc, and 5% cobalt by mass percentage of C60, dissolve them in water, stir well for 12 h under ultrasonic conditions, then transfer the aqueous solution to a reaction kettle, and reduce it at 130 °C under a hydrogen atmosphere (4 MPa) for 20 h. After cooling, filter the obtained precipitate and freeze-dry it to obtain the ruthenium-based benzene partial hydrogenation comparative catalyst 1.

[0066] Comparative Example 2:

[0067] Weigh a certain amount of C60, and then, based on the mass percentage of C60, weigh ruthenium trichloride trihydrate (ruthenium content: 37%), zinc sulfate (zinc content: 40.5%), and cobalt chloride (cobalt content: 45.4%) at the ratios of 10% ruthenium, 50% zinc, and 50% cobalt respectively, and dissolve them in water. Stir well for 12 h under ultrasonic conditions, then transfer the aqueous solution to a reaction kettle, and then reduce it at 130 °C under a hydrogen atmosphere (4 MPa) for 20 h. After cooling, filter the obtained precipitate and freeze-dry it to obtain the ruthenium-based benzene partial hydrogenation comparative catalyst 2.

[0068] Comparative Example 3:

[0069] Weigh a certain amount of C60, and then, based on the mass percentage of C60, weigh ruthenium trichloride trihydrate (ruthenium content: 37%), zinc sulfate (zinc content: 40.5%), and cobalt chloride (cobalt content: 45.4%) at the ratios of 30% ruthenium, 150% zinc, and 150% cobalt respectively, and dissolve them in water. Stir well for 12 h under ultrasonic conditions, then transfer the aqueous solution to a reaction kettle, and then reduce it at 130 °C under a hydrogen atmosphere (4 MPa) for 20 h. After cooling, filter the obtained precipitate and freeze-dry it to obtain the ruthenium-based benzene partial hydrogenation comparative catalyst 3.

[0070] Experimental Examples 1 - 3 and Comparative Experimental Examples 1 - 3

[0071] The ruthenium-based benzene partial hydrogenation catalysts 1 - 3 prepared in Examples 1 - 3 and the ruthenium-based benzene partial hydrogenation comparative catalysts 1 - 3 prepared in Comparative Examples 1 - 3 were respectively used in the reaction of benzene partial hydrogenation to cyclohexene. The reaction conditions were: reaction temperature 150 °C, reaction pressure 4.5 MPa, reaction time 30 min, the molar ratio of benzene to hydrogen 1:2.2, and the proportion of the ruthenium-based benzene partial hydrogenation catalyst in benzene 10%. The specific reaction results are shown in Table 1:

[0072] Table 1: Reaction Results of Catalysts 1 - 3 and Comparative Catalysts 1 - 3 for Benzene Partial Hydrogenation to Cyclohexene

[0073] Catalyst Benzene conversion rate (%) Cyclohexene selectivity (%) Cyclohexene yield (%) Catalyst 1 15.3 85.1 13.0 Catalyst 2 52.7 84.6 44.6 Catalyst 3 42.7 83.7 35.7 Comparative catalyst 1 12.5 68.7 8.6 Comparative catalyst 2 25.3 66.1 16.7 Comparative catalyst 3 21.8 62.9 13.7

[0074] Experimental Example 4

[0075] The basic ruthenium-based benzene partial hydrogenation catalyst 2 prepared in Example 2 was used in a continuous reactor for the reaction of benzene partial hydrogenation to cyclohexene. The reaction conditions were as follows: in a 2 L reactor, the reaction temperature was 150 °C, the amount of catalyst used was 132 g, the benzene flow rate was 50 mL / min, the molar ratio of benzene to hydrogen was 1:2.2, the residence time of benzene in the reactor was 30 min, and the continuous reaction time was 100 h. The specific reaction results are shown in Table 2 below:

[0076] Table 2: Reaction results of benzene partial hydrogenation to cyclohexene after 100 h of reaction of catalyst 2 in a continuous reactor

[0077] Catalyst Benzene conversion rate (%) Cyclohexene selectivity (%) Cyclohexene yield (%) Catalyst 2 51.8 83.2 43.1

[0078] As can be seen from Table 1 and Table 2, the ruthenium-based benzene partial hydrogenation catalyst 2 prepared in the present invention has high activity, high selectivity and good stability when used in the reaction of benzene partial hydrogenation to cyclohexene. This also makes the ruthenium-based benzene partial hydrogenation catalyst 2 prepared in the present invention have a very broad application prospect in the industrial production of catalytic benzene partial hydrogenation to cyclohexene.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A catalyst for partial hydrogenation of benzene, characterized in that, The catalyst uses oxidized fullerene as the catalyst carrier, ruthenium as the main catalyst, and also contains one or more promoters.

2. The catalyst according to claim 1, wherein, The oxidized fullerene is selected from one or more of oxidized C60, C70, C76, C84, C90, C94, C98, and C100, preferably oxidized C60.

3. The catalyst according to claim 1, wherein, Based on the mass of ruthenium, the main catalyst accounts for 1% to 30% of the mass of the catalyst carrier, preferably 10%. Preferably, the promoter is selected from one or more of zinc, aluminum, boron, lanthanum, cerium, iron, copper, cobalt, and magnesium, preferably zinc and cobalt.

4. The catalyst according to claim 1, wherein Based on the mass of the metal, the mass ratio of the main catalyst to the promoter is 1:(2 to 40); more preferably, the promoter is zinc and cobalt, and based on the mass of the metal, the mass ratio of ruthenium, zinc, and cobalt is 1:(1 to 20):(1 to 20), more preferably 1:5:

5.

5. A method for preparing the catalyst according to claim 1, the method comprising the following steps: Step 1: Oxidize the fullerene using ozone, air, oxygen, or hydrogen peroxide, preferably oxidize the fullerene using ozone, to obtain oxidized fullerene as the catalyst carrier; Step 2: Load the ruthenium and the promoter on the oxidized fullerene to obtain the catalyst for partial hydrogenation of benzene.

6. The preparation method according to claim 5, wherein, The said Step 1 includes: Step 1a: Disperse the fullerene in a solvent, then introduce ozone at 0°C to 25°C, after reacting for 0.5 - 2 h, raise the temperature to 25°C to 100°C at a rate of 0.5 - 5°C / min and react for 1 - 10 h to obtain an intermediate; Step 1b: Add a reducing agent to the intermediate obtained in Step 1a, react at a temperature of 25°C to 100°C for 1 to 12 hours, and then obtain the oxidized fullerene as the catalyst carrier through centrifugation, separation, and drying.

7. The preparation method according to claim 6, wherein, In the above Step 1a, the molar ratio of ozone to fullerene is selected from 3:1 - 30:1, preferably 6:

1. Preferably, in the above Step 1a, ozone is introduced first at 0°C, after reacting for 1.5 h, raise the temperature to 60°C at a rate of 1°C / min and react for 5 h to obtain an intermediate. Preferably, in the above Step 1b, the added reducing agent is selected from one or more of dimethyl sulfide, triphenylphosphine, sodium sulfite, and zinc powder, preferably dimethyl sulfide. Preferably, in the above Step 1b, the molar ratio of the reducing agent to ozone in Step 1a is 1:1 to 1:5, preferably 1:2 to 1:

3. Preferably, the reaction temperature in the above Step 1b is 50°C. Preferably, the reaction time in the above Step 1b is 4 h.

8. The preparation method according to claim 5, wherein, The said Step 2 includes: Step 2a: Immerse the oxidized fullerene prepared in Step 1 in an aqueous solution of the precursors of ruthenium and the promoter, perform ultrasonic stirring treatment, filter and dry, and reduce the obtained solid under a hydrogen atmosphere to obtain the catalyst for partial hydrogenation of benzene.

9. According to the preparation method described in claim 8, wherein The precursor of ruthenium is selected from one or two of ruthenium trichloride, ruthenium nitrate, ruthenium acetate, potassium hexachlororuthenate, potassium hexacyanoruthenate, potassium ruthenate, and ruthenium tribromide, preferably ruthenium trichloride. Preferably, the main catalyst accounts for 1% to 30% of the mass of the catalyst carrier, preferably 10%. Preferably, the promoter is selected from one or more of zinc, aluminum, boron, lanthanum, cerium, iron, copper, cobalt, and magnesium, preferably zinc and cobalt; Preferably, the precursor of the promoter is selected from one or more of the sulfate, acetate, halide, and nitrate of the promoter; Preferably, the precursor of zinc is selected from one or more of zinc sulfate, zinc chloride, zinc acetate, and zinc nitrate, preferably zinc sulfate; Preferably, the precursor of cobalt is selected from one or more of cobalt sulfate, cobalt fluoride, cobalt chloride, cobalt bromide, cobalt iodide, cobalt nitrate, cobalt carbonate, and cobalt acetate, preferably cobalt chloride; Preferably, based on the mass of the metal, the mass ratio of the main catalyst to the promoter is 1:(2 to 40); more preferably, the promoter is zinc and cobalt, and based on the mass of the metal, the mass ratios of ruthenium, zinc, and cobalt to the catalyst mass are selected from 1:(1 to 20):(1 to 20), preferably 1:5:5; Preferably, in the step 2a, the ultrasonic stirring treatment time of the oxidized fullerene in the aqueous solution of the precursors of the main catalyst and the promoter is 1 h to 24 h, preferably 12 h; Preferably, in the step 2a, the hydrogen pressure is 1 MPa to 5 MPa, preferably 4 MPa; Preferably, in the step 2a, the temperature is 100 °C to 200 °C, preferably 130 °C; Preferably, in the step 2a, the reduction time in the hydrogen atmosphere is 6 h to 30 h, preferably 20 h.

10. A method for preparing cyclohexene using the catalyst according to any one of claims 1 to 4 or the catalyst prepared by the method according to any one of claims 5 to 9, the method comprising the following steps: Step 1: Mix the catalyst with benzene and react in a hydrogen atmosphere to obtain cyclohexene, Preferably, the catalyst accounts for 1% to 40% of the mass of benzene, preferably 10%; Preferably, the molar ratio of benzene to hydrogen is 1:1 to 1:6, preferably 1:2.2; Preferably, the reaction pressure is 3 MPa - 6 MPa, preferably 4.5 MPa; Preferably, the reaction temperature is 120 °C - 180 °C, preferably 150 °C; Preferably, the reaction time is 10 min to 90 min, preferably 30 min.