A process for the preparation of epoxycyclohexane

Abstract

This invention provides a low-cost, clean, continuous process for the preparation of cyclohexane oxide. The process uses a mixture from the hydrogenation reaction of benzene as raw material, employs a highly active and stable supported heteropolyacid salt as a catalyst, and uses 15%–60% hydrogen peroxide as an oxygen source. Under an inert atmosphere of 0.1–4 MPa, cyclohexane oxide is continuously and on a large scale. This process eliminates the need for distilled and purified cyclohexene as a raw material, significantly reducing raw material costs. Furthermore, by utilizing benzene and cyclohexane in the mixture as solvents, the use of toxic chlorine-containing solvents is avoided. By supporting the heteropolyacid salt, catalyst separation is optimized, reducing catalyst loss and enabling large-scale continuous production of cyclohexane oxide from cyclohexene through catalytic oxidation. This process offers advantages such as low energy consumption, environmental friendliness, mild conditions, and ease of separation and recycling, demonstrating significant industrial application value.

Description

Technical Field

[0001] This invention relates to the field of fine chemicals, and more specifically to a low-cost, clean, continuous process for the preparation of cyclohexane oxide. Background Technology

[0002] Cyclohexane oxide is a chemically active pharmaceutical and fine chemical raw material. It can be used as an intermediate in the synthesis of various high-value-added chemical products, and is also a highly effective organic solvent with a wide range of applications in pharmaceuticals, pesticides, solvents, plasticizers, curing agents, flame retardants, diluents, adhesives, surfactants, and monomers for biodegradable materials. Cyclohexane oxide is an intermediate in the synthesis of the acaricide chlorpyrifos [2-(4-tert-butylphenoxy)cyclohexyl-prop-2-ynylsulfite], and a major raw material for chlorpyrifos emulsifiable concentrate. Currently, its most promising application is the copolymerization of cyclohexane oxide and carbon dioxide to produce polycyclohexene carbonate (PCHC), which is considered a promising alternative to traditional polystyrene (PS) plastics. With the continuous development of applications for cyclohexane oxide, its demand is rapidly increasing.

[0003] The production of cyclohexane oxide can be divided into separation and recovery methods and synthetic methods. Synthetic methods mainly involve hypochlorous acid oxidation, organic peroxide oxidation, molecular oxygen oxidation, and hydrogen peroxide oxidation, all using cyclohexene as a raw material. Among these, hypochlorous acid oxidation is limited in industrial application due to its poor selectivity and severe pollution. Organic peroxide oxidation suffers from drawbacks such as the instability of peroxides, easy decomposition, difficulty in storage, and severe pollution, which significantly restricts its industrial application. Molecular oxygen oxidation generates a large number of byproducts and has poor selectivity for cyclohexane oxide. With the gradual maturation of the selective hydrogenation process for cyclohexene from benzene, the process technology for the catalytic epoxidation of hydrogen peroxide and cyclohexene to produce cyclohexane oxide has attracted considerable attention. This epoxidation technology has low environmental pollution and high molecular utilization, making it a green and environmentally friendly process for producing cyclohexane oxide. Its core lies in the preparation of a selective epoxidation catalyst, because the cyclohexene molecule contains one unsaturated carbon-carbon double bond and multiple active α-H atoms, which can generate various oxides.

[0004] CN1401640A discloses a reaction-controlled phase transfer catalyst in which the catalyst dissolves into the reaction system during the reaction and undergoes an epoxidation reaction. After the reaction, the catalyst precipitates from the reaction system and transforms into a heterogeneous catalyst. This process uses a batch reaction, which suffers from long catalyst precipitation time and large loss in the aqueous phase, leading to high costs. Furthermore, in order to improve catalyst activity and facilitate catalyst recovery, this system is carried out in a highly toxic solvent containing chlorine, which does not meet the requirements of green chemistry. The technical solution of CN101343261B is to remove the aqueous phase from the reaction system during the oxidation reaction after 10%-100% of the hydrogen peroxide has been consumed, while the oil phase continues to react. This allows for complete catalyst precipitation and improves the recovery rate of the oil phase catalyst. However, catalyst loss in the aqueous phase is unavoidable, and olefins must be in excess of hydrogen peroxide. Cyclohexene self-polymerization leads to significant material losses. CN103880781A discloses a method for continuous production of cyclohexane oxide. After the reaction, a mixture of oil phase, water phase and catalyst (solid phase) is separated by a separator. The oil phase is then separated into solvent, cyclohexene and cyclohexane oxide by distillation. Due to the high concentration of cyclohexene and cyclohexane oxide during the reaction, the polymerization of cyclohexene and the ring-opening hydrolysis of cyclohexane oxide lead to low reaction selectivity.

[0005] The catalytic oxidation system composed of titanium-silicon molecular sieve (TS-1) and hydrogen peroxide exhibits excellent catalytic activity and selectivity for epoxides in the propylene epoxidation reaction, with water as the only byproduct. It is an environmentally friendly catalyst, overcoming the problems of complex operation, harsh conditions, and environmental pollution associated with traditional processes. However, when used in the oxidation of cyclohexene to prepare cyclohexane oxide, such as the technical solution disclosed in CN103130747A, oxidation is carried out in a distillation column (i.e., under distillation conditions), where some or all of the packing material is a catalyst containing titanium-silicon molecular sieve, fully utilizing the latent heat of reaction. This system suffers from low cyclohexene conversion and low yield of the target product. Furthermore, the short lifespan of the titanium-silicon molecular sieve catalyst leads to high replacement costs and short replacement cycles in the distillation column, impacting production efficiency.

[0006] Developing an efficient, green, low-cost, and continuous technology for the oxidation of cyclohexene to produce cyclohexane oxide has significant application value.

[0007] To address the aforementioned technical problems, the present invention aims to provide a novel process for the continuous large-scale production of cyclohexane oxide using a mixture following the hydrogenation reaction of benzene as raw material, a highly active and stable supported phosphotungstic heteropolyacid salt as catalyst, and 30-50% hydrogen peroxide as oxygen source. This process eliminates the need for distilled and purified cyclohexene as a raw material, significantly reducing raw material costs. Furthermore, by utilizing cyclohexane and benzene in the mixture as solvents, the use of toxic chlorine-containing solvents is avoided. By supporting the phosphotungstic heteropolyacid salt, catalyst separation is optimized, reducing catalyst loss and enabling large-scale continuous production of cyclohexane oxide from cyclohexene through catalytic oxidation, laying the foundation for its large-scale application. Summary of the Invention

[0008] This invention provides a low-cost, clean, continuous process for the preparation of cyclohexane oxide. The process uses a mixture from the hydrogenation reaction of benzene as raw material, employs a highly active and stable supported heteropolyacid salt as a catalyst, and uses 15%–60% hydrogen peroxide as an oxygen source. Under an inert atmosphere of 0.1–4 MPa, cyclohexane oxide is continuously and on a large scale. This process eliminates the need for distilled and purified cyclohexene as a raw material, significantly reducing raw material costs. Furthermore, by utilizing benzene and cyclohexane in the mixture as solvents, the use of toxic chlorine-containing solvents is avoided. By supporting the heteropolyacid salt, catalyst separation is optimized, reducing catalyst loss and enabling large-scale continuous production of cyclohexane oxide from cyclohexene through catalytic oxidation. This process offers advantages such as low energy consumption, environmental friendliness, mild conditions, and ease of separation and recycling, demonstrating significant industrial application value.

[0009] 1. Using the mixture after the hydrogenation reaction of benzene as raw material, instead of using high-purity cyclohexene, reduces costs;

[0010] 2. By utilizing benzene and cyclohexane in the mixture as solvents, no additional solvents are needed, thus avoiding the use of toxic chlorine-containing solvents.

[0011] 3. Reacting under an inert atmosphere helps dissolve cyclohexene and controls the dangers posed by the generation of oxygen during the reaction.

[0012] 4. Heteropolyacid loading simplifies separation and reduces loss.

[0013] 5. Adjusting the microstructure of the heteropolyacid catalyst improves the selectivity of cyclohexane oxide, eliminating the need for additional additives.

[0014] 6. It avoids a series of problems encountered in continuous production caused by the introduction of additives, and can be used for large-scale continuous production.

[0015] Technical solution of the present invention

[0016] 1. A method for preparing cyclohexene oxide, comprising the following specific steps: using the mixed solution after benzene hydrogenation reaction as raw material, supported heteropolyacid salt as catalyst, and hydrogen peroxide with a mass concentration of 15% - 60% as oxygen source, continuously preparing cyclohexene oxide under an inert atmosphere of 0.1 - 4 MPa;

[0017] The preparation method of the supported heteropolyacid salt catalyst: dispersing metal carbonate MCO3 (divalent metal M = one or more of Mn, Cu, Co, Ni) into deionized water, and dropping an aqueous solution of H3XN

[0020] , , 12 , 48 , , 2-n , ,

[0019] , ,

[0023] ,

[0018] ,

[0022] , ,

[0021] , O 48 (X = one or two of P, As; N = one or two of W, Mo) into the obtained mixture; stirring the obtained mixture at room temperature for 2 - 8 h, adding deionized water and carrier S and continuing to stir for 2 - 8 h, filtering the precipitate, washing three times with deionized water and ethanol respectively, and drying the obtained solid under vacuum at 30 - 60 °C for 1 - 8 h to obtain M n H 2-n XN 12 O 48 / S (M = one or more of Mn, Cu, Co, Ni); (abbreviated as M - POM / S, where X = one or two of P, As; N = one or two of W, Mo; M = one or more of Mn, Cu, Co, Ni; 0.01 < n < 1.99, preferably 0.3 ≤ n ≤ 1.8);

[0018] The loading amount of the heteropolyacid salt in the supported heteropolyacid salt catalyst is 0.001 - 0.1 mol / Kg carrier S; the carrier S of the supported heteropolyacid salt catalyst is one or more of the alkali metal salts of zeolite Y, MCM - 41, and ZSM - 5;

[0019] The addition amount of the supported heteropolyacid salt catalyst is 5% - 50% of the mass of the mixed solution after benzene hydrogenation reaction (reaction material stream containing benzene, cyclohexene and cyclohexane), preferably 10% - 40%; the mass percentage content of cyclohexene in the mixed solution after benzene hydrogenation reaction (reaction material stream containing benzene, cyclohexene and cyclohexane) is 10% - 95%, preferably 20% - 70%;

[0020] The epoxidation reaction temperature is 30 °C - 65 °C;

[0021] The process flow is characterized by including the following process steps: ​​​​B) Mix the reaction material stream obtained in step A) with hydrogen peroxide and the above-mentioned supported phosphotungstic heteropolyacid salt catalyst in an epoxidation reactor, and directly carry out an epoxidation reaction in the reactor to prepare cyclohexene oxide.

[0024] In the above method, C) after the epoxidation reaction is completed, cyclohexene oxide is separated and purified by distillation, and benzene, cyclohexane and unreacted cyclohexene are transported to the benzene selective hydrogenation reactor again for selective hydrogenation and recycled.

[0025] 2. In the above method, the process of preparing cyclohexene by selective hydrogenation of benzene is as follows: after replacing the atmosphere in the hydrogenation reactor with nitrogen, successively add a selective hydrogenation catalyst, a dispersant, an additive and water to obtain a catalyst reaction slurry. Hydrogen is transported to the hydrogenation reactor for replacement and then filled to the reaction pressure. Benzene is transported to the reactor to obtain a reaction stream of benzene / water, and a selective hydrogenation reaction is carried out;

[0026] After the reaction is completed, the organic phase is separated from the catalyst reaction slurry in a phase separator. The catalyst reaction slurry is recycled and transported to the hydrogenation reactor, and the organic phase is the reaction material stream of the reaction mixture for preparing cyclohexene by selective hydrogenation of benzene (which contains benzene, cyclohexene and cyclohexane).

[0027] 3. In the above method, the raw material for epoxidation is the reaction material stream of the reaction mixture for preparing cyclohexene by selective hydrogenation of benzene after preliminary dehydration treatment; the preliminary dehydration treatment is the dehydration process of the reaction mixture for selective hydrogenation; after dehydration, the percentage content of water in the reaction material stream < 0.5%;

[0028] The mass percentage content of cyclohexene in the reaction material stream after preliminary treatment is 10% - 95%, preferably 20% - 70%.

[0029] 4. In the above method, the supported heteropolyacid salt catalyst M n H 2-n XN 12 O 48 / S, by adjusting the addition amount of metal M, the selectivity of the reactant cyclohexene oxide can be adjusted. The value range of n is 0.01 < n < 1.99, preferably 0.3 ≤ n ≤ 1.8; the supported heteropolyacid salt catalyst used can also be a mixture of catalysts with different addition amounts of metal M, thereby adjusting the selectivity of the reactant cyclohexene oxide, and the selectivity of cyclohexene oxide > 95%.

[0030] 5. In the above method, the cyclohexene epoxidation reaction is carried out under an inert atmosphere, and the pressure of the inert atmosphere is 0.1 - 4 MPa, preferably 0.5 - 2 MPa; the inert atmosphere is one or more of nitrogen, argon, helium and other atmospheres;

[0031] The mass concentration of the hydrogen peroxide oxygen source used is 15% to 60%, preferably 30% to 50%.

[0032] 6. In the above method, after the reaction is completed, cyclohexane oxide is purified by distillation, and benzene, cyclohexane and unreacted cyclohexene are hydrogenated and recycled.

[0033] After a single cyclohexene epoxidation reaction, the cyclohexane oxide is separated by distillation. The material stream containing water, benzene, cyclohexane, and a small amount of cyclohexene can be directly recycled back to the hydrogenation reactor for further hydrogenation.

[0034] 7. In the above method, after two or more cycles of hydrogenation and epoxidation to separate epichlorohydrin, if the mass percentage of cyclohexane in the resulting material stream containing water, benzene, cyclohexane and a small amount of cyclohexene is >85%, the resulting material stream can be completely hydrogenated to co-produce cyclohexane.

[0035] 8. In the above method, the supported heteropolyacid salt catalyst is a heterogeneous catalyst, which does not require the participation of additives, is easy to separate and recycle, and can realize the large-scale continuous production of cyclohexane oxide.

[0036] This process eliminates the need for distilled and purified cyclohexene as a raw material, significantly reducing raw material costs. Simultaneously, by utilizing benzene and cyclohexane in the mixture as solvents, the use of toxic chlorinated solvents is avoided. By supporting and molding heteropolyacid salts, catalyst separation is optimized, reducing catalyst loss and enabling large-scale continuous production of cyclohexane oxide from cyclohexene. This process offers advantages such as low energy consumption, environmental friendliness, mild conditions, and ease of separation and recycling, demonstrating significant industrial application value. Attached Figure Description

[0037] Figure 1 A schematic diagram of a low-cost, clean, continuous process for preparing cyclohexane oxide. Detailed Implementation

[0038] The present invention will be described in detail below with reference to the embodiments, but the scope of the present invention is not limited to the following embodiments.

[0039] Figure 1 A schematic diagram of a low-cost, clean, continuous process for the preparation of cyclohexane oxide, as shown below. Figure 1 The diagram illustrates a low-cost, clean, continuous process for preparing cyclohexane oxide, specifically including the following equipment:

[0040] 1. Benzene selective hydrogenation reactor;

[0041] Two-phase separator: Separation of the oil phase and the aqueous phase of the hydrogenation reaction liquid;

[0042] 3. Membrane separation tower: Separates a small amount of water from the oil phase of the hydrogenation reaction liquid;

[0043] 4. Epoxidation reactor: Cyclohexene epoxidation reactor;

[0044] 5. Distillation column: Separates light components from the epoxidation reaction solution, including benzene, small amounts of cyclohexene, cyclohexane, and water;

[0045] 6. Distillation column: Crude cyclohexane oxide is distilled to obtain pure product;

[0046] 11, 23 Nitrogen pipelines: to be supplied to hydrogenation reactor 1 and epoxidation reactor 4 as needed;

[0047] 12. Pipeline for transporting zinc salt aqueous solution and alkaline solution with selective hydrogenation of benzene;

[0048] 13. Hydrogen pipeline: to be supplied to hydrogenation reactor 1 as needed;

[0049] 14. Benzene delivery pipeline: to deliver to hydrogenation reactor 1 as needed;

[0050] 15. Hydrogenation catalyst added to the channel;

[0051] 16. The hydrogenation reaction solution is transported to phase separator 2 via pipeline 16.

[0052] The hydrogen circulation pipeline 17, combined with pipeline 13, is then fed into hydrogenation reactor 1;

[0053] The circulation pipeline of the aqueous phase of the hydrogenation reaction liquid 18 is combined with pipeline 12 and then introduced into hydrogenation reactor 1;

[0054] 19. Exhaust gas ducts;

[0055] 20. The hydrogenation reaction liquid oil phase containing a small amount of water is transported to membrane separation tower 3 via a pipeline.

[0056] The circulating pipeline for the water separated by the membrane separation tower 21 is combined with pipelines 18 and 12;

[0057] 22. The reaction liquid containing benzene, cyclohexene and cyclohexane is transported to the epoxidation reactor 4 via a pipeline.

[0058] 24. Hydrogen peroxide is added to the pipeline and transported to the epoxidation reactor 4;

[0059] 25. The supported heteropoly acid salt catalyst is added to the epoxidation reactor 4 through the addition channel;

[0060] 26. Epoxidation reaction liquid is transported to distillation column 5 via pipeline 26.

[0061] 27. Epoxidation reaction exhaust gas pipeline;

[0062] 28. Crude cyclohexane oxide is transported to distillation column 6 via pipeline 28.

[0063] The light fraction (benzene / small amount of cyclohexene / cyclohexane / water) obtained from distillation column 5 is transported to hydrogenation reactor 1 via a circulating pipeline.

[0064] 30% Cyclohexene polymer and other high-boiling-point fractions are discharged through the pipeline;

[0065] 31. Collection pipeline for pure cyclohexane oxide;

[0066] 32. Light fractions containing trace amounts of cyclohexane oxide were collected;

[0067] 33 exhaust gas duct, after being combined with ducts 19 and 27, is treated by combustion;

[0068] Nitrogen delivery pipeline 11, hydrogen delivery pipeline 13, zinc salt aqueous solution and alkali solution delivery pipeline 12, benzene delivery pipeline 14, and hydrogenation catalyst addition channel 15 are respectively connected to hydrogenation reactor 1. After the hydrogenation reaction is completed, the hydrogen gas after the hydrogenation reaction is recycled back to pipeline 13 via pipeline 17, and the resulting hydrogenated reaction liquid is transported to phase separator 2 via pipeline 16. The hydrogenated reaction liquid is separated in phase separator 2, and the resulting aqueous phase is recycled back to hydrogenation reactor 1 via phase separator substrate pipeline 18 and pipeline 12. The resulting waste gas is discharged through the top pipeline 19 of the phase separator, and the resulting oil phase is transported to membrane separation tower 3 via pipeline 20 for further water removal. The water separated in membrane separation tower 3 is recycled back to hydrogenation reactor 1 via pipeline 21 and pipelines 18 and 12, and the oil phase separated at the top of membrane separation tower 3 is transported to epoxidation reactor 4 via pipeline 22. In addition, nitrogen delivery pipeline 23, hydrogen peroxide delivery pipeline 24, and supported heteropoly acid salt catalyst addition channel are also connected. Channels 25 are connected to the epoxidation reactor 4. The mixture containing benzene, cyclohexene, and cyclohexane from pipe 22 undergoes an epoxidation reaction in the epoxidation reactor 4. The resulting waste gas is discharged through pipe 27 at the top of the epoxidation reactor. The resulting epoxidized reaction liquid is transported to the distillation column 5 via pipe 26. After distillation in the distillation column 5, a mixed light fraction containing benzene, a small amount of cyclohexene, cyclohexane, and water is obtained at the top of the column. This mixed light fraction is transported through pipe 29. As needed, the product is combined with pipeline 14 and recycled back to hydrogenation reactor 1, or transported to all hydrogenation reactors via pipeline 29 and pipeline 34 to co-produce cyclohexane. The crude cyclohexane oxide product obtained from the bottom of the distillation column is transported to distillation column 6 for distillation via pipeline 28. Polycyclohexene and other polymers are collected from the bottom of distillation column 6 via pipeline 30, and a light fraction containing a small amount of cyclohexane oxide is collected from the upper part via pipeline 32. Pure cyclohexane oxide is collected via pipeline 31, and the waste gas obtained from distillation is discharged via pipeline 33. The waste gas from pipelines 19, 29, and 33 is combined and then treated by combustion.

[0069] Example 1

[0070] Catalyst preparation

[0071] 5 mmol of metal carbonate MCO3 (with +2 valence metal M being Mn, Cu, Co, or Ni) was dispersed in 30 mL of deionized water, and 20 mL of H3PW was added dropwise to the resulting mixture. 12 O 48 A 10 mmol aqueous solution was used; the resulting mixture was stirred at room temperature for 6 h, then 2 L of deionized water and 330 g of zeolite Y sodium salt support were added, and stirring was continued for 6 h. The precipitate was filtered, washed three times with deionized water and ethanol, respectively, and the resulting solid was dried under vacuum at 50 °C for 4 h to obtain M. 0.5 H 2.0 PW 12 O 48 / Zeolite Y sodium salt, the loading of heteropolyacid in this series of supported heteropolyacid acid catalysts is 0.03 mol / Kg support (M is Mn, Cu, Co or Ni respectively). (Abbreviation M-POM / Y-1; M is Mn, Cu, Co, Ni respectively; n = 0.5);

[0072] Example 2

[0073] Catalyst preparation: 10 mmol of metal carbonate MCO3 (with +2 valence metal M being Mn, Cu, Co, or Ni) was dispersed in 30 mL of deionized water, and 20 mL of H3PW was added dropwise to the resulting mixture. 12 O 48 A 10 mmol aqueous solution was used; the resulting mixture was stirred at room temperature for 6 h, 2 L of deionized water and 1 kg of zeolite Y sodium salt support were added, and stirring was continued for 6 h. The precipitate was filtered, washed three times with deionized water and ethanol, respectively, and the resulting solid was dried under vacuum at 50 °C for 4 h to obtain MHPW. 12 O 48 / Zeolite Y sodium salt, the loading of heteropolyacid in this series of supported heteropolyacid acid catalysts is 0.01 mol / Kg support (M is Mn, Cu, Co or Ni respectively). (Abbreviation M-POM / Y-2; M is Mn, Cu, Co or Ni respectively; n=1);

[0074] Example 3

[0075] Catalyst preparation: 10 mmol of metal carbonate MCO3 (with +2 valence metal M being Mn, Cu, Co, or Ni) was dispersed in 30 mL of deionized water, and 20 mL of H3PW was added dropwise to the resulting mixture. 12 O 48 A 10 mmol aqueous solution was used; the resulting mixture was stirred at room temperature for 6 h, then 2 L of deionized water and 500 g of MCM-41 support were added, and stirring was continued for 6 h. The precipitate was filtered, washed three times with deionized water and ethanol, respectively, and the resulting solid was dried under vacuum at 50 °C for 4 h to obtain MHPW. 12 O48 / MCM-41 refers to a series of supported heteropolyacid acid salt catalysts where the heteropolyacid acid salt loading is 0.02 mol / Kg support (M represents Mn, Cu, Co, or Ni). (Abbreviated as M-POM / MCM41-1; M represents Mn, Cu, Co, or Ni; n = 1);

[0076] Example 4

[0077] Catalyst preparation: 10 mmol of metal carbonate MCO3 (with +2 valence metal M being Mn, Cu, Co, or Ni) was dispersed in 30 mL of deionized water, and 20 mL of H3PW was added dropwise to the resulting mixture. 12 O 48 A 10 mmol aqueous solution was used; the resulting mixture was stirred at room temperature for 6 h, then 2 L of deionized water and 1 kg of MCM-41 support were added, and stirring was continued for 6 h. The precipitate was filtered, washed three times with deionized water and ethanol, respectively, and the resulting solid was dried under vacuum at 50 °C for 4 h to obtain MHPW. 12 O 48 / MCM-41 refers to a series of supported heteropolyacid acid salt catalysts where the heteropolyacid acid salt loading is 0.01 mol / Kg support (M represents Mn, Cu, Co, or Ni). (Abbreviated as M-POM / MCM41-2; M represents Mn, Cu, Co, or Ni; n = 1);

[0078] Example 5

[0079] After being purged with nitrogen three times, selective hydrogenation reactor 1 was sequentially added via pipeline 12 with 40.37 kg of 90 wt% Ru-8 wt% Zn-2 wt% O hydrogenation catalyst, 201.85 kg of monoclinic zirconia dispersant, 167.45 kg of zinc sulfate additive, and 720 kg of water. After stirring at 145°C, a catalyst reaction slurry was obtained. Hydrogen was then introduced into the hydrogenation reactor for purging, followed by purging to 4.5 MPa. Benzene was then introduced into the hydrogenation reactor via pipeline 14 to obtain a benzene / water reaction stream with a mass concentration of 28 wt%. The total flow rate of the benzene-water slurry was 1000 kg / h. The slurry was then introduced via pipeline 13 at a flow rate of 72 kg / h. Hydrogen gas is introduced to carry out a selective reduction reaction. The mass ratio of benzene, cyclohexene, and cyclohexane in the resulting hydrogenation reaction solution is 4.4:5.9:1. This hydrogenation reaction solution is transported to phase separator 2 through pipeline 16. In phase separator 2, the hydrogenation reaction solution is separated, and water accounting for 98.2% of the total water in the system is separated through pipeline 18. The resulting oil phase (the reactant stream of the reaction mixture for the selective hydrogenation of benzene to cyclohexene) is transported to membrane separation tower 3 (ultrafiltration membrane UF) through pipeline 20 for further water removal. The oil phase separated at the top of membrane separation tower 3 is transported to epoxidation reactor 4 through pipeline 22. The water content of this oil phase is determined by Karl Fischer method to be 0.2%.

[0080] In the epoxidation reactor 4, 105 kg of supported heteropolyacid acid catalyst (Cu-POM / Y-1, with a heteropolyacid acid loading of 0.03 mol / kg support) is added through channel 25. Nitrogen gas is introduced through pipe 23 to maintain the reaction pressure at 1.0 MPa. The reaction mixture for the selective hydrogenation of benzene to cyclohexene (a mixture containing benzene, cyclohexene, and cyclohexane (water content of 0.2%)) flows in through pipe 22 at a flow rate of 290.4 kg / h. 30% hydrogen peroxide flows in through pipe 24 at a flow rate of 210 kg / h. The mixture is transported and subjected to cyclohexene epoxidation in reactor 4 at 50°C. The generated waste gas is discharged through pipe 27 at the top of the epoxidation reactor. The resulting epoxidation reaction liquid is transported to distillation column 5 through pipe 26. After distillation in distillation column 5, a mixed light fraction containing benzene, a small amount of cyclohexene, cyclohexane and water is obtained at the top of the column (cyclohexene mass content is 2.5%). When the mass percentage of cyclohexane in the mixed light fraction is >85%, the resulting material stream can be transported to all hydrogenation reactors through pipe 29 and pipe 34 to co-produce cyclohexane. When the mass percentage of cyclohexane in the mixed light fraction is <85%, it is recycled back to the hydrogenation reactor 1 via pipes 29 and 14. The crude cyclohexane oxide product obtained from the bottom of the distillation column is transported to distillation column 6 for rectification via pipe 28. Polycyclohexene and other polymers are collected from the bottom of distillation column 6 via pipe 30, and a light fraction containing a small amount of cyclohexane oxide is collected from the top via pipe 32. On average, 175.0 kg / h of pure cyclohexane oxide is collected via pipe 31 in each hydrogenation cycle, with a GC purity of 99.5%. The yield of cyclohexane oxide relative to hydrogen peroxide is 95%. The mass ratio of cyclohexane oxide to cyclohexane is 5.4:1.

[0081] Example 6

[0082] After nitrogen purging, selective hydrogenation reactor 1 is followed by the sequential addition of 50.25 kg of 87.5 wt% Ru-10 wt% Zn-2.5 wt% O hydrogenation catalyst, 250.50 kg of monoclinic zirconium dioxide dispersant, 251.25 kg of zinc sulfate additive, and 720 kg of water via pipeline 12. The mixture is stirred at 150°C to obtain a catalyst reaction slurry. Hydrogen is then introduced into the hydrogenation reactor for purging, followed by purging to 5.0 MPa. Benzene is then introduced into the hydrogenation reactor via pipeline 14 to obtain a benzene / water reaction stream with a mass concentration of 28 wt%. The total flow rate of the benzene-water slurry is 1000 kg / h. The slurry is then introduced via pipeline 13 at a rate of 50 kg / h. Hydrogen gas is introduced at a flow rate of h to carry out a selective reduction reaction. The mass ratio of benzene, cyclohexene, and cyclohexane in the resulting hydrogenation reaction solution is 4.4:5.9:1. This hydrogenation reaction solution is transported to phase separator 2 through pipeline 16. In phase separator 2, the hydrogenation reaction solution is separated, and water accounting for 98.2% of the total water in the system is separated through pipeline 18. The resulting oil phase (the reactant stream of the reaction mixture for the selective hydrogenation of benzene to cyclohexene) is transported to membrane separation tower 3 (ultrafiltration membrane UF) through pipeline 20 for further water removal. The oil phase separated at the top of membrane separation tower 3 is transported to epoxidation reactor 4 through pipeline 22. The water content of this oil phase is determined by Karl Fischer method to be 0.1%.

[0083] In the epoxidation reactor 4, 100 kg of supported heteropolyacid acid catalyst (Ni-POM / Y-2, with a heteropolyacid acid loading of 0.01 mol / kg support) is added through channel 25. Argon gas is introduced through pipe 23 to maintain the reaction pressure at 2.0 MPa. The reaction material stream of the reaction mixture for the selective hydrogenation of benzene to cyclohexene (a mixture containing benzene, cyclohexene, and cyclohexane (water content of 0.2%)) flows in through pipe 22 at a flow rate of 290 kg / h. 50% hydrogen peroxide flows in through pipe 24 at a flow rate of 126 kg / h. The mixture is transported and subjected to cyclohexene epoxidation in reactor 4 at 55°C. The generated waste gas is discharged through pipe 27 at the top of the epoxidation reactor. The resulting epoxidation reaction liquid is transported to distillation column 5 through pipe 26. After distillation in distillation column 5, a mixed light fraction containing benzene, a small amount of cyclohexene, cyclohexane and water is obtained at the top of the column (cyclohexene content is 1.5%). When the mass percentage of cyclohexane in the mixed light fraction is >85%, the resulting material stream can be transported to all hydrogenation reactors through pipe 29 and pipe 34 to co-produce cyclohexane. When the mass percentage of cyclohexane in the mixed light fraction is <85%, it is recycled back to the hydrogenation reactor 1 via pipes 29 and 14. The crude cyclohexane oxide product obtained from the bottom of the distillation column is transported to distillation column 6 for rectification via pipe 28. Polycyclohexene and other polymers are collected from the bottom of distillation column 6 via pipe 30, and a light fraction containing a small amount of cyclohexane oxide is collected from the top via pipe 32. On average, 173.8 kg / h of pure cyclohexane oxide is collected via pipe 31 in each hydrogenation cycle, with a GC purity of 99.8%. The yield of cyclohexane oxide relative to hydrogen peroxide is 98%. The mass ratio of cyclohexane oxide to cyclohexane is 5.3:1.

[0084] Example 7

[0085] After nitrogen purging, selective hydrogenation reactor 1 is followed by the sequential addition of 40.37 kg of 85 wt% Ru-12 wt% Zn-3 wt% O hydrogenation catalyst, 210.85 kg of monoclinic zirconium dioxide dispersant, 180.20 kg of zinc sulfate additive, and 680 kg of water via pipeline 12. The mixture is stirred at 148°C to obtain a catalyst reaction slurry. Hydrogen is then introduced into the hydrogenation reactor for purging, followed by purging to 5.0 MPa. Benzene is then introduced into the hydrogenation reactor via pipeline 14 to obtain a 32 wt% benzene / water reaction stream. The total flow rate of the benzene-water slurry is 1000 kg / h. The slurry is then introduced via pipeline 13 at a flow rate of 50 kg / h. Hydrogen gas is introduced to carry out a selective reduction reaction. The mass ratio of benzene, cyclohexene, and cyclohexane in the resulting hydrogenation reaction solution is 2.5:3.9:1. This hydrogenation reaction solution is transported to phase separator 2 through pipeline 16. In phase separator 2, the hydrogenation reaction solution is separated, and water accounting for 98.5% of the total water in the system is separated through pipeline 18. The resulting oil phase (the reactant stream of the reaction mixture for the selective hydrogenation of benzene to cyclohexene) is transported to membrane separation tower 3 (ultrafiltration membrane UF) through pipeline 20 for further water removal. The oil phase separated at the top of membrane separation tower 3 is transported to epoxidation reactor 4 through pipeline 22. The water content of this oil phase is determined by Karl Fischer method to be 0.1%.

[0086] In the epoxidation reactor 4, 120 kg of supported heteropolyacid acid catalyst (Co-POM / MCM41-1, with a heteropolyacid acid loading of 0.02 mol / kg support) is added through channel 25. Nitrogen gas is introduced through pipe 23 to maintain the reaction pressure at 2.5 MPa. The reaction mixture for the selective hydrogenation of benzene to cyclohexene (a mixture containing benzene, cyclohexene, and cyclohexane (water content of 0.2%)) flows in through pipe 22 at a flow rate of 332 kg / h. 50% hydrogen peroxide flows in through pipe 145 kg / h. 24. The resulting mixture is subjected to cyclohexene epoxidation in reactor 4 at 63°C. The generated waste gas is discharged through pipe 27 at the top of the epoxidation reactor. The resulting epoxidation reaction liquid is transported to distillation column 5 through pipe 26. After distillation in distillation column 5, a mixed light fraction containing benzene, a small amount of cyclohexene, cyclohexane and water is obtained at the top of the column (cyclohexene content is 2.5%). When the mass percentage of cyclohexane in the mixed light fraction is >85%, the resulting material stream can be transported to all hydrogenation reactors through pipe 29 and pipe 34 to co-produce cyclohexane. When the mass percentage of cyclohexane in the mixed light fraction is <85%, it is recycled back to the hydrogenation reactor 1 via pipes 29 and 14. The crude cyclohexane oxide product obtained from the bottom of the distillation column is transported to distillation column 6 for rectification via pipe 28. Polycyclohexene and other polymers are collected from the bottom of distillation column 6 via pipe 30, and a light fraction containing a small amount of cyclohexane oxide is collected from the top via pipe 32. On average, 203.2 kg / h of pure cyclohexane oxide is collected via pipe 31 in each hydrogenation cycle, with a GC purity of 99.5%. The yield of cyclohexane oxide relative to hydrogen peroxide is 95%. The mass ratio of cyclohexane oxide to cyclohexane is 3.8:1.

[0087] Example 8

[0088] After nitrogen purging, selective hydrogenation reactor 1 is followed by the sequential addition of 40.37 kg of 90 wt% Ru-8 wt% Zn-2 wt% O hydrogenation catalyst, 180.55 kg of monoclinic zirconium dioxide dispersant, 150.44 kg of zinc sulfate additive, and 740 kg of water via pipeline 12. The mixture is stirred at 150°C to obtain a catalyst reaction slurry. Hydrogen is then introduced into the hydrogenation reactor for purging, followed by purging to 4.0 MPa. Benzene is then introduced into the hydrogenation reactor via pipeline 14 to obtain a benzene / water reaction stream with a mass concentration of 26 wt%. The total flow rate of the benzene-water slurry is 1000 kg / h. The slurry is then introduced via pipeline 13 at a flow rate of 50 kg / h. Hydrogen gas is introduced to carry out a selective reduction reaction. The mass ratio of benzene, cyclohexene, and cyclohexane in the resulting hydrogenation reaction solution is 3.1:2.28:1. This hydrogenation reaction solution is transported to phase separator 2 through pipeline 16. In phase separator 2, the hydrogenation reaction solution is separated, and water accounting for 98.4% of the total water in the system is separated through pipeline 18. The resulting oil phase (the reactant stream of the reaction mixture for the selective hydrogenation of benzene to cyclohexene) is transported to membrane separation tower 3 (ultrafiltration membrane UF) through pipeline 20 for further water removal. The oil phase separated at the top of membrane separation tower 3 is transported to epoxidation reactor 4 through pipeline 22. The water content of this oil phase is determined by Karl Fischer method to be 0.1%.

[0089] In the epoxidation reactor 4, 80 kg of supported heteropolyacid acid catalyst (Mn-POM / MCM41-2, with a heteropolyacid acid loading of 0.01 mol / kg support) is added through channel 25. Helium gas is introduced through pipe 23 to maintain the reaction pressure at 1.5 MPa. The reaction mixture for the selective hydrogenation of benzene to cyclohexene (a mixture containing benzene, cyclohexene, and cyclohexane (water content of 0.2%)) flows in through pipe 22 at a flow rate of 267.7 kg / h. 30% hydrogen peroxide flows in through pipe 22 at a flow rate of 132 kg / h. 24. The resulting mixture undergoes cyclohexene epoxidation in reactor 4 at 60°C. The generated waste gas is discharged through pipe 27 at the top of the epoxidation reactor. The resulting epoxidation reaction liquid is transported to distillation column 5 via pipe 26. After distillation in distillation column 5, a mixed light fraction containing benzene, a small amount of cyclohexene, cyclohexane, and water (cyclohexene content is 4.0%) is obtained at the top of the column. When the mass percentage of cyclohexane in the mixed light fraction is >85%, the resulting material stream can be transported to all hydrogenation reactors via pipe 29 and pipe 34 to co-produce cyclohexane. When the mass percentage of cyclohexane in the mixed light fraction is <85%, it is recycled back to the hydrogenation reactor 1 via pipes 29 and 14. The crude cyclohexane oxide product obtained from the bottom of the distillation column is transported to distillation column 6 for rectification via pipe 28. Polycyclohexene and other polymers are collected from the bottom of distillation column 6 via pipe 30, and a light fraction containing a small amount of cyclohexane oxide is collected from the top via pipe 32. On average, 108.6 kg / h of pure cyclohexane oxide is collected via pipe 31 in each hydrogenation cycle, with a GC purity of 99.5%. The yield of cyclohexane oxide relative to hydrogen peroxide is 97%. The mass ratio of cyclohexane oxide to cyclohexane is 2.2:1.

Claims

1. A method for preparing cyclohexane oxide, characterized in that: Cyclohexane oxide was continuously prepared using a mixture of benzene hydrogenation reaction products as raw materials, supported heteropoly acid salts as catalysts, and hydrogen peroxide with a mass concentration of 15% to 60% as an oxygen source under an inert atmosphere of 0.1 to 4 MPa. The preparation method of the supported heteropolyacid acid salt catalyst is as follows: A metal carbonate MCO3 is dispersed in deionized water, wherein M is a +2 valence metal, and M = one or more of Mn, Cu, Co, and Ni. H3XN is then added dropwise to the resulting mixture. 12 O 48 An aqueous solution of X = one or two of P and As; N = one or two of W and Mo; the resulting mixture is stirred at room temperature for 2-8 h, then deionized water and support S are added and stirring is continued for 2-8 h. The precipitate is filtered and washed three times with deionized water and ethanol, respectively. The resulting solid is vacuum dried at 30-60 °C for 1-8 h to obtain M. n H 2-n XN 12 O 48 / S, abbreviated as M-POM / S, where M = one or more of Mn, Cu, Co, and Ni; X = one or two of P and As; N = one or two of W and Mo; 0.01 <n<1.99, The loading amount of the heteropolyacid in the supported heteropolyacid catalyst is 0.001-0.1 mol / Kg support S; the support S of the supported heteropolyacid catalyst is one or more of the following: alkali metal salt of zeolite Y, MCM-41, ZSM-5; The amount of the supported heteropolyacid acid catalyst added is 5%-50% of the mass of the mixture after the benzene hydrogenation reaction, the mass percentage of cyclohexene in the mixture after the benzene hydrogenation reaction is 10%-95%, and the mixture after the benzene hydrogenation reaction is a reactant stream containing benzene, cyclohexene and cyclohexane. The epoxidation reaction temperature is 30℃-65℃; The process flow includes the following steps: A) Cyclohexene is prepared by selective hydrogenation of benzene. The resulting selective hydrogenation mixture is pre-treated by dehydration to obtain a reactant stream containing benzene, cyclohexene and cyclohexane. B) The reactant stream obtained in step A) is mixed with hydrogen peroxide and the above-mentioned supported heteropolyacid acid catalyst in an epoxidation reactor to directly carry out the epoxidation reaction in the reactor to prepare cyclohexane oxide.

2. The method according to claim 1, characterized in that, C) After the epoxidation reaction is completed, the cyclohexane oxide is purified by distillation, and the benzene, cyclohexane and unreacted cyclohexene are sent to the benzene selective hydrogenation reactor for selective hydrogenation and reused.

3. The method according to claim 1, characterized in that, Supported heteropolyacid acid catalyst M n H 2-n XN 12 O 48 / S 0.3≤n≤1.8; the amount of the supported heteropolyacid acid catalyst added is 10-40% of the mass of the mixture after the benzene hydrogenation reaction; the mass percentage of cyclohexene in the mixture after the benzene hydrogenation reaction is 20%-70%.

4. The method according to claim 1 or 2, characterized in that, The process of selective hydrogenation of benzene to prepare cyclohexene is as follows: after replacing the atmosphere in the hydrogenation reactor with nitrogen, a catalyst, a dispersant, an additive and water are added in sequence to obtain a catalyst reaction slurry. Hydrogen is then transported to the hydrogenation reactor for replacement and then charged to the reaction pressure. Benzene is then transported to the reactor to obtain a benzene / water reaction stream for selective hydrogenation reaction. After the reaction is completed, the organic phase and the catalyst reaction slurry are separated in a phase separator. The catalyst reaction slurry is then circulated to the hydrogenation reactor. The organic phase is the reaction material stream of the reaction mixture for the selective hydrogenation of benzene to cyclohexene, which contains benzene, cyclohexene and cyclohexane.

5. The method according to claim 1, characterized in that, The raw material used in epoxidation is a reaction stream from the selective hydrogenation reaction mixture of benzene to cyclohexene, which has undergone preliminary dehydration treatment. This preliminary dehydration treatment is a process for dehydrating the selective hydrogenation reaction mixture. After dehydration, the water percentage in the reaction stream is <0.5%. The mass percentage of cyclohexene in the pre-treated reaction stream is 10%-95%.

6. The method according to claim 5, characterized in that, The mass percentage of cyclohexene in the pre-processed reaction material stream is 20%-70%.

7. The method according to claim 1, characterized in that, The supported heteropolyacid salt catalyst M n H 2-n XN 12 O 48 By adjusting the addition amount of metal M in / S, the selectivity of the reactant cyclohexene oxide can be adjusted. The value range of n is 0.01 < n < 1.

99. The supported heteropolyacid salt catalyst used can also be a mixture of catalysts with different addition amounts of metal M, thereby adjusting the selectivity of the reactant cyclohexene oxide, and the selectivity of cyclohexene oxide > 95%.

8. The method according to claim 1, characterized in that, The cyclohexene epoxidation reaction is carried out under an inert atmosphere with a pressure of 0.1-4 MPa; the inert atmosphere is one or more of nitrogen, argon, and helium. The mass concentration of the hydrogen peroxide oxygen source used is 15%~60%.

9. The method according to claim 1, characterized in that, The cyclohexene epoxidation reaction was carried out under an inert atmosphere with a pressure of 0.5-2 MPa; the mass concentration of the hydrogen peroxide oxygen source used was 30%-50%.

10. The method according to claim 1 or 2, characterized in that, After the reaction is complete, cyclohexane oxide is purified by distillation, and benzene, cyclohexane and unreacted cyclohexene are hydrogenated and recycled. After a single cyclohexene epoxidation reaction, the cyclohexane oxide is separated by distillation. The material stream containing water, benzene, cyclohexane, and a small amount of cyclohexene can be directly recycled back to the hydrogenation reactor for further hydrogenation.

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