CN118084829A - Method for preparing epoxycyclohexane - Google Patents

Abstract

The present invention provides a low-cost and clean continuous process for preparing epoxy cyclohexane, which uses a mixed solution after benzene hydrogenation reaction as a raw material, a supported heteropolyacid salt with high activity and high stability as a catalyst, 15% to 60% of hydrogen peroxide as an oxygen source, and an inert atmosphere of 0.1-4MPa, and continuously prepares epoxy cyclohexane on a large scale. The process does not require cyclohexene purified by rectification as a raw material, which greatly reduces the cost of raw materials. At the same time, by using benzene and cyclohexane in the mixed solution as solvents, the use of toxic chlorinated solvents is avoided. By molding the heteropolyacid salt load, the separation problem of the catalyst is optimized, and the loss of the catalyst is reduced, and the large-scale continuous production of epoxy cyclohexane by catalytic oxidation of cyclohexene can be realized. The process has the advantages of low energy consumption, green environmental protection, mild conditions, easy separation and recycling, and has significant industrial application value.

Description

A method for preparing cyclohexene oxide

Technical Field

The invention relates to the field of fine chemicals, and in particular to a low-cost and clean continuous process for preparing cyclohexene oxide.

Background technique

Cyclohexene oxide is a pharmaceutical raw material and fine chemical raw material with active chemical properties. It can not only be used as an intermediate to synthesize a variety of chemical products with higher added value, but also is an organic solvent with strong dissolving ability. It has a very wide range of uses and can be used in medicine, pesticides, solvents, plasticizers, curing agents, flame retardants, diluents, adhesives, surfactants and biodegradable material monomers. Cyclohexene oxide is an intermediate for the synthesis of the pesticide acaricide propargite [2-(4-tert-butylphenoxy) cyclohexyl-prop-2-ynyl sulfite] and the main raw material for propargite emulsifiable concentrate; the most promising application at present is the copolymerization of cyclohexene oxide and carbon dioxide to produce polycyclohexene carbonate (PCHC), which is considered to be a promising alternative to traditional polystyrene (PS) plastics. With the continuous development of the uses of cyclohexene oxide, its demand has also increased rapidly.

The acquisition of cyclohexene oxide can be divided into separation and recovery method and synthesis method. The synthesis method mainly uses cyclohexene as raw material, including hypochlorous acid oxidation method, organic peroxide oxidation method, molecular oxygen oxidation method and hydrogen peroxide oxidation method. Among them, the industrial application of hypochlorous acid oxidation method has been limited due to poor selectivity and serious pollution. The peroxide in the organic peroxide oxidation method is unstable, easy to decompose, difficult to store, and has serious pollution, which greatly limits the industrial application of the organic peroxide epoxidation method. The molecular oxygen oxidation method will generate a large amount of by-products, and the selectivity of cyclohexene oxide is poor. With the gradual maturity of the process of selective hydrogenation of benzene to prepare cyclohexene, the process technology of preparing cyclohexene oxide by catalytic epoxidation of hydrogen peroxide and cyclohexene has attracted much attention. This epoxidation technology has low environmental pollution and high molecular utilization. It is a green and environmentally friendly process route for preparing cyclohexene oxide. Its core is the preparation of selective epoxidation catalysts. This is because the cyclohexene molecule contains an unsaturated carbon-carbon double bond and multiple active α-H, which can generate a variety of oxides.

CN1401640A discloses a reaction-controlled phase transfer catalyst, wherein the catalyst is dissolved in the reaction system during the reaction process to generate an epoxidation reaction, and after the reaction is completed, the catalyst is separated from the reaction system and converted into a heterogeneous catalyst. The process adopts an intermittent reaction, and there are problems such as a long catalyst separation time and a large loss in the water phase, which leads to high costs. In addition, in order to improve the activity of the catalyst and facilitate the recovery of the catalyst, the system is carried out in a chlorine-containing solvent with high toxicity, which does not meet the requirements of green chemistry. The technical solution of CN101343261B is that during the oxidation reaction, after 10%-100% of hydrogen peroxide is consumed, the water phase is removed from the reaction system, and the oil phase continues to react, so that the catalyst can be completely separated and the oil phase catalyst recovery rate can be improved. However, catalyst loss is inevitable in the water phase, and olefins must be in excess of hydrogen peroxide, and cyclohexene self-polymerization brings about a large material loss. CN103880781A discloses a method for continuously producing cyclohexene oxide. After the reaction is completed, an oil phase, an aqueous phase and a catalyst (solid phase) mixture are separated through a separator. The oil phase is distilled to separate the solvent, cyclohexene and cyclohexene oxide. Since the concentrations of cyclohexene and cyclohexene oxide are high during the reaction, cyclohexene polymerization and cyclohexene oxide ring-opening hydrolysis result in low reaction selectivity.

The catalytic oxidation system composed of titanium silicon molecular sieve (TS-1) and hydrogen peroxide has very good catalytic activity and selectivity for epoxy compounds in propylene epoxidation reaction, and the only byproduct is water. It is an environmentally friendly catalyst, which overcomes the problems of complex operation, harsh conditions, environmental pollution, etc. in the traditional process. However, it is used in the process of cyclohexene oxidation to prepare cyclohexene oxide. For example, the technical solution disclosed in CN103130747A is oxidized in a distillation tower (i.e., under distillation conditions), and part or all of the fillers in the distillation tower are catalysts containing titanium silicon molecular sieves, which fully utilizes the latent heat of reaction. The epoxidation of the titanium silicon molecular sieve catalyst in this system has the problems of low cyclohexene conversion rate and low yield of the target product. At the same time, the titanium silicon molecular sieve catalyst has a short life, and the catalyst replacement cost in the distillation tower is high and the replacement cycle is short, which affects the production efficiency.

The development of an efficient, green, low-cost and continuous production technology for cyclohexene oxidation to prepare cyclohexene oxide has important application value.

In order to solve the above technical problems, the purpose of the present invention is to provide a new process for continuously preparing cyclohexene oxide on a large scale by using the mixed liquid after benzene hydrogenation reaction as raw material, using a highly active and stable supported phosphotungstic heteropoly acid salt as a catalyst, and 30-50% hydrogen peroxide as an oxygen source. The process does not require cyclohexene purified by distillation as a raw material, which greatly reduces the cost of raw materials. At the same time, by using cyclohexane and benzene in the mixed liquid as solvents, the use of toxic chlorinated solvents is avoided. By loading and molding the phosphotungstic heteropoly acid salt, the separation problem of the catalyst is optimized, the loss of the catalyst is reduced, and the large-scale continuous production of cyclohexene oxide by catalytic oxidation of cyclohexene can be achieved, laying the foundation for its large-scale application.

Summary of the invention

The present invention provides a low-cost and clean continuous process for preparing cyclohexene oxide. The process uses a mixed liquid after benzene hydrogenation reaction as a raw material, uses a highly active and highly stable supported heteropolyacid salt as a catalyst, and uses 15% to 60% hydrogen peroxide as an oxygen source. Under an inert atmosphere of 0.1-4MPa, cyclohexene oxide is continuously prepared on a large scale. The process does not require cyclohexene purified by distillation as a raw material, which greatly reduces the cost of raw materials. At the same time, by using benzene and cyclohexane in the mixed liquid as solvents, the use of toxic chlorinated solvents is avoided. By forming the heteropolyacid salt load, the separation problem of the catalyst is optimized, the loss of the catalyst is reduced, and large-scale continuous production of cyclohexene oxide by catalytic oxidation of cyclohexene can be achieved. The process has the advantages of low energy consumption, green environmental protection, mild conditions, easy separation and recycling, and has significant industrial application value.

1. Use the mixed liquid after benzene hydrogenation reaction as raw material instead of high-purity cyclohexene as raw material, thus reducing costs;

2. By using benzene and cyclohexane in the mixed liquid as solvents, no additional solvent is required, thus avoiding the use of toxic chlorinated solvents.

3. Reacting under an inert atmosphere helps dissolve cyclohexene and control the dangers of oxygen produced during the reaction.

4. Heteropolyacid loading simplifies separation and reduces loss

5. The microstructure of the heteropolyacid catalyst is adjusted to improve the selectivity of cyclohexene oxide without the need for additional additives

6. It avoids a series of problems faced by continuous production caused by the introduction of additives and can be produced continuously on a large scale.

Technical solution of the present invention

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

The preparation method of the supported heteropolyacid catalyst comprises the following steps: dispersing metal carbonate MCO ₃ (+2-valent metal M=one or more than one of Mn, Cu, Co and Ni) in deionized water, dropping an aqueous solution of H ₃ XN ₁₂ O ₄₈ (X=one or more than one of P and As; N=one or more than one of W and Mo) into the obtained mixture; stirring the obtained mixture at room temperature for 2-8 hours, adding deionized water and carrier S and continuing to stir for 2-8 hours, filtering the precipitate, washing with deionized water and ethanol three times respectively, and vacuum drying the obtained solid at 30-60° C. for 1-8 hours to obtain M _n H _2-n XN ₁₂ O ₄₈ /S (M＝one or more than one of Mn, Cu, Co, Ni); (abbreviated as M-POM/S, wherein X＝one or more than one of P and As; N＝one or more than one of W and Mo; M＝one or more than one of Mn, Cu, Co, Ni; 0.01<n<1.99, preferably 0.3≤n≤1.8);

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

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

The epoxidation reaction temperature is 30°C-65°C;

The process flow is characterized by the following process steps:

A) preparing cyclohexene by selective hydrogenation of benzene, and subjecting the obtained selective hydrogenation mixed liquid to preliminary treatment for removing water to obtain a reactant stream containing benzene, cyclohexene and cyclohexane;

B) mixing the reactant stream obtained in step A) with hydrogen peroxide and the above-mentioned supported phosphotungstic heteropolyacid salt catalyst in an epoxidation reactor, and directly carrying out epoxidation reaction in the reactor to prepare cyclohexene oxide.

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

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, a selective hydrogenation catalyst, a dispersant, an additive and water are added in sequence to obtain a catalyst reaction slurry, hydrogen is transported to the hydrogenation reactor and replaced, and then filled to the reaction pressure, benzene is transported to the reactor to obtain a benzene/water reaction stream, and a selective hydrogenation reaction is performed;

After the reaction is completed, the organic phase and the catalyst reaction slurry are separated in a phase separator, and the catalyst reaction slurry is circulated to the hydrogenation reactor. The organic phase is the reactant stream (containing benzene, cyclohexene and cyclohexane) of the reaction mixture for selective hydrogenation of benzene to prepare cyclohexene.

3. In the above method, the raw material used for epoxidation is a reactant stream of a reaction mixture of benzene selectively hydrogenated to prepare cyclohexene, which is subjected to a preliminary treatment for dehydration; the preliminary dehydration treatment is a dehydration process of the reaction mixture of selective hydrogenation; after dehydration, the water content in the reactant stream is less than 0.5%;

The mass percentage content of cyclohexene in the preliminary treated reaction material flow is 10%-95%, preferably 20%-70%.

4. In the above method, the selectivity of the reactant cyclohexene oxide can be adjusted by adjusting the amount of the metal M added in the supported _{heteropolyacid} salt catalyst _{MnH2 - nXN12O48} /S, and 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 amounts of metal M added, thereby adjusting the selectivity of the reactant cyclohexene oxide, and the selectivity of cyclohexene oxide is >95%.

5. In the above method, the cyclohexene epoxidation reaction is carried out under an inert atmosphere with a pressure of 0.1-4 MPa, preferably 0.5-2 MPa; the inert atmosphere is one or two or more of nitrogen, argon, helium and the like;

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

6. In the above method, after the reaction is completed, the cyclohexene oxide is separated and purified by distillation, and the benzene, cyclohexane and unreacted cyclohexene are hydrogenated and recycled again;

After a single cyclohexene epoxidation reaction, after distillation to separate cyclohexyl oxide, the material flow containing water, benzene, cyclohexane and a small amount of cyclohexene can be directly recycled back to the hydrogenation reactor for another hydrogenation cycle.

7. In the above method, after more than two cycles of hydrogenation and epoxidation to separate epichlorohydrin, when the mass percentage of cyclohexane in the obtained material stream containing water, benzene, cyclohexane and a small amount of cyclohexene is greater than 85%, the obtained material stream can be fully hydrogenated to co-produce cyclohexane.

8. In the above method, the supported heteropolyacid salt catalyst is a heterogeneous catalyst, does not require the participation of additives, is easy to separate and circulate, and can achieve large-scale continuous production of cyclohexene oxide.

The process does not require distilled and purified cyclohexene as raw material, which greatly reduces the cost of raw materials. At the same time, by using benzene and cyclohexane in the mixed solution as solvents, the use of toxic chlorinated solvents is avoided. By loading and molding heteropolyacid salts, the separation problem of the catalyst is optimized, the loss of catalyst is reduced, and large-scale continuous production of epoxy cyclohexane by catalytic oxidation of cyclohexene can be achieved. The process has the advantages of low energy consumption, green environmental protection, mild conditions, easy separation and recycling, and has significant industrial application value.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a continuous process flow for low-cost clean preparation of cyclohexene oxide.

Detailed ways

The present invention is described in detail below in conjunction with embodiments, but the scope of the present invention is not limited to the following embodiments.

FIG1 is a schematic diagram of a continuous process flow for preparing cyclohexene oxide cleanly at low cost. As shown in FIG1 , a continuous process flow for preparing cyclohexene oxide cleanly at low cost specifically includes the following equipment:

1. Benzene selective hydrogenation reactor;

2-phase separator: separation of oil phase and water phase of hydrogenation reaction liquid;

3. Membrane separation tower: to separate a small amount of water from the oil phase of the hydrogenation reaction liquid;

4 Epoxidation reactor: cyclohexene epoxidation reactor;

5. Distillation tower: separates the light components in the epoxidation reaction liquid, including benzene, a small amount of cyclohexene, cyclohexane and water;

6. Distillation tower: distill the crude cyclohexene oxide product to obtain the pure product;

11, 23 nitrogen pipeline: transported to the hydrogenation reactor 1 and the epoxidation reactor 4 as needed;

12 pipelines for conveying aqueous zinc salt solution and alkali solution for selective hydrogenation of benzene;

13 Hydrogen pipeline: transported to hydrogenation reactor 1 as needed;

14 Benzene delivery pipeline: delivered to hydrogenation reactor 1 as needed;

15 hydrogenation catalyst adding channel;

16 The hydrogenation reaction liquid is transported to the phase separator 2 pipeline;

17 is a hydrogen circulation pipeline, which is combined with pipeline 13 and then introduced into hydrogenation reactor 1;

18 is a circulation pipeline for the aqueous phase of the hydrogenation reaction liquid, which is combined with pipeline 12 and then introduced into the hydrogenation reactor 1;

19 Exhaust pipe;

20 The oil phase of the hydrogenation reaction liquid containing a small amount of water is transported to the membrane separation tower 3;

21 is a circulating pipeline for separating water from the membrane separation tower, and is combined with pipelines 18 and 12;

22 a reaction liquid delivery pipeline containing benzene, cyclohexene and cyclohexane, which is delivered to the epoxidation reactor 4;

24 Hydrogen peroxide is added into the pipeline and transported to the epoxidation reactor 4;

25 The supported heteropoly acid salt catalyst is added into the epoxidation reactor 4;

26 epoxidation reaction liquid delivery pipeline, delivered to the distillation tower 5;

27 Epoxidation reaction waste gas pipeline;

28 cyclohexene oxide crude product delivery pipeline, delivered to the distillation tower 6;

The light fraction (benzene/a small amount of cyclohexene/cyclohexane/water) obtained from the distillation tower 5 is transported to the hydrogenation reactor 1 through a circulation pipeline;

30. Pipe for removing high boiling point fractions such as cyclohexene polymer;

31 Collection pipeline for pure cyclohexene oxide;

32 A light fraction containing a small amount of cyclohexene oxide is produced;

33 exhaust gas pipeline, after merging with pipelines 19 and 27, is burned;

The nitrogen delivery pipeline 11, the hydrogen delivery pipeline 13, the zinc salt aqueous solution and alkali solution delivery pipeline 12, the benzene delivery pipeline 14 and the hydrogenation catalyst addition channel 15 are respectively connected to the hydrogenation reactor 1. After the hydrogenation reaction is completed, the hydrogen after the hydrogenation reaction is circulated back to the pipeline 13 through the pipeline 17, and the obtained hydrogenation reaction liquid is transported to the phase separator 2 through the pipeline 16; the hydrogenation reaction liquid is separated in the phase separator 2, and the obtained water phase is combined through the phase separator substrate pipeline 18 and the pipeline 12 to circulate back to the hydrogenation reactor 1, the obtained waste gas is discharged through the pipeline 19 at the top of the phase separator, and the obtained oil phase is transported to the membrane separation tower 3 through the pipeline 20 for further water removal; the water separated in the membrane separation tower 3 is combined with the pipelines 18 and 12 to circulate back to the hydrogenation reactor 1, and the oil phase separated at the top of the membrane separation tower 3 is transported to the epoxidation reactor 4 through the pipeline 22; in addition, the nitrogen delivery pipeline 23, the hydrogen peroxide delivery pipeline 24, the loaded heteropolyacid catalyst addition channel 15 are connected to the hydrogenation reactor 1 through the pipeline 21, the hydrogen peroxide delivery pipeline 24, the loaded heteropolyacid catalyst addition channel 16, the hydrogenation reaction liquid is separated in the phase separator 2, and the hydrogenation reaction liquid is transported to the phase separator 2; ...; the hydrogenation reaction liquid is separated in the phase separator 2; the hydrogenation reaction liquid is separated in the phase separator 2; the hydrogenation reaction liquid is separated in the phase separator 2; the hydrogenation reaction liquid is separated in the phase The channels 25 are respectively connected to the epoxidation reactor 4. After the mixed material containing benzene, cyclohexene and cyclohexane from the pipeline 22 undergoes epoxidation reaction in the epoxidation reactor 4, the waste gas generated is discharged from the pipeline 27 at the top of the epoxidation reactor, and the obtained epoxidation reaction liquid is transported to the distillation tower 5 through the pipeline 26; after the reaction liquid is rectified in the distillation tower 5, a mixed light fraction containing benzene, a small amount of cyclohexene, cyclohexane and water is obtained at the top of the tower, and the mixed light fraction is combined with the pipeline 14 as needed through the pipeline 29 and then recycled back to the hydrogenation reactor 1, or transported to all hydrogenation reactors through the pipeline 29 and the pipeline 34 to co-produce cyclohexane, and the crude cyclohexene oxide product obtained at the bottom of the distillation tower is transported to the distillation tower 6 for rectification through the pipeline 28; at the bottom of the distillation tower 6, polymers such as polycyclohexene are extracted through the pipeline 30, and a light fraction containing a small amount of cyclohexene oxide is extracted through the pipeline 32 at the top, and pure cyclohexene oxide is extracted through the pipeline 31, and the waste gas obtained by distillation is discharged through the pipeline 33. The exhaust gas pipes 19, 29 and 33 are combined and then burned.

Example 1

Catalyst preparation

5mmol of metal carbonate MCO ₃ (+2-valent metal M is Mn, Cu, Co or Ni) is dispersed in 30mL of deionized water, and 20mL of H ₃ PW ₁₂ O ₄₈ (10mmol) aqueous solution is added dropwise to the obtained mixture; the obtained mixture is stirred at room temperature for 6h, 2L of deionized water and 330g of zeolite Y sodium salt carrier are added, and stirring is continued for 6h, the precipitate is filtered, and washed with deionized water and ethanol three times respectively. The obtained solid is vacuum dried at 50°C for 4h to obtain M _0.5 H _2.0 PW ₁₂ O ₄₈ /zeolite Y sodium salt. The loading amount of heteropolyacid salt in this series of supported heteropolyacid salt catalysts is 0.03mol/Kg carrier (M is Mn, Cu, Co or Ni). (abbreviated as M-POM/Y-1; M is Mn, Cu, Co, Ni; n=0.5);

Example 2

Preparation of catalyst: 10 mmol of metal carbonate MCO ₃ (+2-valent metal M is Mn, Cu, Co or Ni) is dispersed in 30 mL of deionized water, and 20 mL of H ₃ PW ₁₂ O ₄₈ (10 mmol) aqueous solution is added dropwise to the obtained mixture; the obtained mixture is stirred at room temperature for 6 h, 2 L of deionized water and 1 kg of zeolite Y sodium salt carrier are added, and stirring is continued for 6 h, the precipitate is filtered, and washed with deionized water and ethanol three times respectively. The obtained solid is vacuum dried at 50°C for 4 h to obtain MHPW ₁₂ O ₄₈ /zeolite Y sodium salt. The loading amount of heteropolyacid salt in this series of supported heteropolyacid salt catalysts is 0.01 mol/kg carrier (M is Mn, Cu, Co or Ni). (abbreviated as M-POM/Y-2; M is Mn, Cu, Co or Ni; n=1);

Example 3

Preparation of catalyst: 10 mmol of metal carbonate MCO ₃ (+2-valent metal M is Mn, Cu, Co or Ni) is dispersed in 30 mL of deionized water, and 20 mL of H ₃ PW ₁₂ O ₄₈ (10 mmol) aqueous solution is added dropwise to the obtained mixture; the obtained mixture is stirred at room temperature for 6 h, 2 L of deionized water and 500 g of MCM-41 carrier are added, and stirring is continued for 6 h. The precipitate is filtered, and washed with deionized water and ethanol three times respectively. The obtained solid is vacuum dried at 50°C for 4 h to obtain MHPW ₁₂ O ₄₈ /MCM-41. The loading amount of heteropolyacid salt in this series of supported heteropolyacid salt catalysts is 0.02 mol/Kg carrier (M is Mn, Cu, Co or Ni). (abbreviated as M-POM/MCM41-1; M is Mn, Cu, Co or Ni; n=1);

Example 4

Preparation of catalyst: 10 mmol of metal carbonate MCO ₃ (+2-valent metal M is Mn, Cu, Co or Ni) is dispersed in 30 mL of deionized water, and 20 mL of H ₃ PW ₁₂ O ₄₈ (10 mmol) aqueous solution is added dropwise to the obtained mixture; the obtained mixture is stirred at room temperature for 6 h, 2 L of deionized water and 1 kg of MCM-41 carrier are added, and stirring is continued for 6 h, the precipitate is filtered, and washed three times with deionized water and ethanol respectively. The obtained solid is vacuum dried at 50°C for 4 h to obtain MHPW ₁₂ O ₄₈ /MCM-41. The loading amount of heteropolyacid salt in this series of supported heteropolyacid salt catalysts is 0.01 mol/kg carrier (M is Mn, Cu, Co or Ni). (abbreviated as M-POM/MCM41-2; M is Mn, Cu, Co or Ni; n=1);

Example 5

After the selective hydrogenation reactor 1 was replaced with nitrogen three times, 40.37 kg of 90 wt% Ru-8 wt% Zn-2 wt% O hydrogenation catalyst, 201.85 kg of monoclinic zirconium dioxide dispersant, 167.45 kg of zinc sulfate additive and 720 kg of water were added in sequence through pipeline 12, and the catalyst reaction slurry was obtained after stirring at 145 ° C. Hydrogen was transported to the hydrogenation reactor and replaced, and the hydrogen was filled to 4.5 MPa. Benzene was transported to the hydrogenation reactor through pipeline 14 to obtain a reaction flow of benzene/water with a mass concentration of 28 wt%. The total flow rate of the benzene water slurry was 1000 kg/h, and then the flow rate of 72 kg/h was 200 kg/h through pipeline 13. Hydrogen is introduced in large amounts to carry out a selective reduction reaction, and the mass ratio of benzene, cyclohexene and cyclohexane in the obtained hydrogenation reaction liquid is 4.4:5.9:1; the hydrogenation reaction liquid is transported to a phase separator 2 through a pipeline 16; the hydrogenation reaction liquid is separated in the phase separator 2, and water is separated out through a pipeline 18, accounting for 98.2% of the total water content in the system, and the obtained oil phase (reactant stream of the reaction mixture for preparing cyclohexene by selective hydrogenation of benzene) is transported to a membrane separation tower 3 (ultrafiltration membrane UF) through a pipeline 20 for further water removal; the oil phase separated at the top of the membrane separation tower 3 is transported to an epoxidation reactor 4 through a pipeline 22; the water mass content of the oil phase sampled and measured by the Karl Fischer method is 0.2%.

105 kg of a supported heteropolyacid catalyst (Cu-POM/Y-1, with a supported heteropolyacid of 0.03 mol/kg carrier) was added to the epoxidation reactor 4 through the channel 25, and nitrogen was introduced through the pipeline 23 to maintain the reaction pressure at 1.0 MPa. The reactant stream of the reaction mixture for preparing cyclohexene by selective hydrogenation of benzene (a mixture containing benzene, cyclohexene and cyclohexane (with a water content of 0.2%)) flowed in through the pipeline 22 at a flow rate of 290.4 kg/h, and 30% hydrogen peroxide flowed in through the pipeline 24 at a flow rate of 210 kg/h. The obtained mixture is transported at 50° C. in a reactor 4 for epoxidation of cyclohexene, and the generated waste gas is discharged from a pipe 27 at the top of the epoxidation reactor. The obtained epoxidation reaction liquid is transported to a distillation tower 5 via a pipe 26; after the reaction liquid is rectified in the distillation tower 5, a mixed light fraction (the mass content of cyclohexene is 2.5%) containing benzene, a small amount of cyclohexene, cyclohexane and water is obtained at the top of the tower. When the mass percentage of cyclohexane in the mixed light fraction is greater than 85%, the obtained material flow 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 less than 85%, it is combined through pipeline 29 and pipeline 14 and then recycled back to the hydrogenation reactor 1. The crude cyclohexene oxide product obtained at the bottom of the distillation tower is transported to the distillation tower 6 for distillation through pipeline 28; at the bottom of the distillation tower 6, polymers such as polycyclohexene are produced through pipeline 30, and light fractions containing a small amount of cyclohexene oxide are produced through pipeline 32. In each hydrogenation cycle, an average of 175.0 kg/h of pure cyclohexene oxide is produced through pipeline 31, with a GC purity of 99.5%. The yield of cyclohexene oxide relative to hydrogen peroxide is 95%. The mass ratio of co-produced cyclohexene oxide and cyclohexane is 5.4:1.

Example 6

After the selective hydrogenation reactor 1 was replaced with nitrogen, 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 were added in sequence through pipeline 12, and the catalyst reaction slurry was obtained after stirring at 150 ° C. The hydrogen was transported to the hydrogenation reactor and replaced, and the hydrogen was filled to 5.0 MPa. Benzene was transported to the hydrogenation reactor through pipeline 14 to obtain a reactant flow of benzene/water with a mass concentration of 28 wt%. The total flow rate of the benzene-water slurry was 1000 kg/h, and then the benzene-water slurry was transported to the hydrogenation reactor at a rate of 50 kg/h through pipeline 13. h flow rate of hydrogen to carry out selective reduction reaction, the mass ratio of benzene, cyclohexene and cyclohexane in the obtained hydrogenation reaction liquid is 4.4:5.9:1; the hydrogenation reaction liquid is transported to the phase separator 2 through the pipeline 16; the hydrogenation reaction liquid is separated in the phase separator 2, and the water separated by the pipeline 18 accounts for 98.2% of the total water content in the system, and the obtained oil phase (reactant stream of the reaction mixture of selective hydrogenation of benzene to prepare cyclohexene) is transported to the membrane separation tower 3 (ultrafiltration membrane UF) through the pipeline 20 for further dehydration; the oil phase separated at the top of the membrane separation tower 3 is transported to the epoxidation reactor 4 through the pipeline 22; the water content of the oil phase sampled and measured by the Karl Fischer method is 0.1%.

100 kg of a supported heteropolyacid catalyst (Ni-POM/Y-2, with a supported heteropolyacid of 0.01 mol/kg carrier) was added to the epoxidation reactor 4 through the channel 25, and argon was introduced through the pipeline 23 to maintain the reaction pressure at 2.0 MPa. The reactant stream of the reaction mixture for preparing cyclohexene by selective hydrogenation of benzene (a mixture containing benzene, cyclohexene and cyclohexane (with a water content of 0.2%)) flowed in through the pipeline 22 at a flow rate of 290 kg/h, and 50% hydrogen peroxide was introduced into the reaction mixture through the pipeline 24 at a flow rate of 126 kg/h. The obtained mixture is transported at 55° C. in a reactor 4 for epoxidation of cyclohexene, and the generated waste gas is discharged from a pipe 27 at the top of the epoxidation reactor. The obtained epoxidation reaction liquid is transported to a distillation tower 5 via a pipe 26; after the reaction liquid is rectified in the distillation tower 5, a mixed light fraction (cyclohexene content is 1.5%) containing benzene, a small amount of cyclohexene, cyclohexane and water is obtained at the top of the tower. When the mass percentage of cyclohexane in the mixed light fraction is greater than 85%, the obtained material flow 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 less than 85%, it is combined through pipeline 29 and pipeline 14 and then recycled back to the hydrogenation reactor 1. The crude cyclohexene oxide product obtained at the bottom of the distillation tower is transported to the distillation tower 6 for distillation through pipeline 28; at the bottom of the distillation tower 6, polymers such as polycyclohexene are produced through pipeline 30, and light fractions containing a small amount of cyclohexene oxide are produced through pipeline 32. In each hydrogenation cycle, an average of 173.8 kg/h of pure cyclohexene oxide is produced through pipeline 31, with a GC purity of 99.8%. The yield of cyclohexene oxide relative to hydrogen peroxide is 98%. The mass ratio of co-produced cyclohexene oxide and cyclohexane is 5.3:1.

Example 7

After the selective hydrogenation reactor 1 was replaced with nitrogen, 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 were added in sequence through pipeline 12, and the catalyst reaction slurry was obtained after stirring at 148 ° C. The hydrogen was transported to the hydrogenation reactor and replaced, and the hydrogen was filled to 5.0 MPa. Benzene was transported to the hydrogenation reactor through pipeline 14 to obtain a reactant flow of benzene/water with a mass concentration of 32 wt%. The total flow rate of the benzene-water slurry was 1000 kg/h, and then the benzene-water slurry was transported to the hydrogenation reactor at a flow rate of 50 kg/h through pipeline 13. Hydrogen is introduced at a flow rate to carry out a selective reduction reaction, and the mass ratio of benzene, cyclohexene and cyclohexane in the obtained hydrogenation reaction liquid is 2.5:3.9:1; the hydrogenation reaction liquid is transported to the phase separator 2 through the pipeline 16; the hydrogenation reaction liquid is separated in the phase separator 2, and the water separated through the pipeline 18 accounts for 98.5% of the total water content in the system, and the obtained oil phase (reactant stream of the reaction mixture of selective hydrogenation of benzene to prepare cyclohexene) is transported to the membrane separation tower 3 (ultrafiltration membrane UF) through the pipeline 20 for further dehydration; the oil phase separated at the top of the membrane separation tower 3 is transported to the epoxidation reactor 4 through the pipeline 22; the water content of the oil phase sampled and measured by the Karl Fischer method is 0.1%.

120 kg of a supported heteropolyacid catalyst (Co-POM/MCM41-1, with a supported heteropolyacid of 0.02 mol/kg carrier) was added to the epoxidation reactor 4 through the channel 25, and nitrogen was introduced through the pipeline 23 to maintain the reaction pressure at 2.5 MPa. The reactant stream of the reaction mixture for preparing cyclohexene by selective hydrogenation of benzene (a mixture containing benzene, cyclohexene and cyclohexane (with a water content of 0.2%)) flowed in through the pipeline 22 at a flow rate of 332 kg/h, and 50% hydrogen peroxide was introduced through the pipeline 23 at a flow rate of 145 kg/h. The obtained mixture is transported through pipe 24, and cyclohexene is epoxidized in reactor 4 at 63°C. The generated waste gas is discharged through pipe 27 at the top of the epoxidation reactor. The obtained epoxidation reaction liquid is transported to distillation tower 5 through pipe 26. After the reaction liquid is rectified in distillation tower 5, a mixed light fraction (cyclohexene content is 2.5%) containing benzene, a small amount of cyclohexene, cyclohexane and water is obtained at the top of the tower. When the mass percentage of cyclohexane in the mixed light fraction is greater than 85%, the obtained material flow 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 less than 85%, it is combined through pipeline 29 and pipeline 14 and then recycled back to the hydrogenation reactor 1. The crude cyclohexene oxide product obtained at the bottom of the distillation tower is transported to the distillation tower 6 for distillation through pipeline 28; at the bottom of the distillation tower 6, polymers such as polycyclohexene are produced through pipeline 30, and light fractions containing a small amount of cyclohexene oxide are produced through pipeline 32. In each hydrogenation cycle, an average of 203.2 kg/h of pure cyclohexene oxide is produced through pipeline 31, with a GC purity of 99.5%. The yield of cyclohexene oxide relative to hydrogen peroxide is 95%. The mass ratio of co-produced cyclohexene oxide and cyclohexane is 3.8:1.

Example 8

After the selective hydrogenation reactor 1 was replaced with nitrogen, 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 were added in sequence through pipeline 12, and the catalyst reaction slurry was obtained after stirring at 150 ° C. The hydrogen was transported to the hydrogenation reactor and replaced, and the hydrogen was filled to 4.0 MPa. Benzene was transported to the hydrogenation reactor through pipeline 14 to obtain a reaction flow of benzene/water with a mass concentration of 26 wt%. The total flow rate of the benzene water slurry was 1000 kg/h, and then the flow rate of 50 kg/h was 200 kg/h through pipeline 13. Hydrogen is introduced in large amounts to carry out a selective reduction reaction, and the mass ratio of benzene, cyclohexene and cyclohexane in the obtained hydrogenation reaction liquid is 3.1:2.28:1; the hydrogenation reaction liquid is transported to a phase separator 2 through a pipeline 16; the hydrogenation reaction liquid is separated in the phase separator 2, and water is separated out through a pipeline 18, accounting for 98.4% of the total water content in the system, and the obtained oil phase (reactant stream of the reaction mixture for preparing cyclohexene by selective hydrogenation of benzene) is transported to a membrane separation tower 3 (ultrafiltration membrane UF) through a pipeline 20 for further water removal; the oil phase separated at the top of the membrane separation tower 3 is transported to an epoxidation reactor 4 through a pipeline 22; the water content of the oil phase sampled and measured by the Karl Fischer method is 0.1%.

80 kg of a supported heteropolyacid catalyst (Mn-POM/MCM41-2, with a supported heteropolyacid of 0.01 mol/kg carrier) was added to the epoxidation reactor 4 through the channel 25, and helium was introduced through the pipeline 23 to maintain the reaction pressure at 1.5 MPa. The reactant stream of the reaction mixture for preparing cyclohexene by selective hydrogenation of benzene (a mixture containing benzene, cyclohexene and cyclohexane (with a water content of 0.2%)) flowed in through the pipeline 22 at a flow rate of 267.7 kg/h, and 30% hydrogen peroxide was introduced through the pipeline 23 at a flow rate of 132 kg/h. The obtained mixture is transported through pipe 24, and cyclohexene is epoxidized in reactor 4 at 60° C. The generated waste gas is discharged through pipe 27 at the top of the epoxidation reactor. The obtained epoxidation reaction liquid is transported to distillation tower 5 through pipe 26. After the reaction liquid is rectified in distillation tower 5, a mixed light fraction (cyclohexene content is 4.0%) containing benzene, a small amount of cyclohexene, cyclohexane and water is obtained at the top of the tower. When the mass percentage of cyclohexane in the mixed light fraction is greater than 85%, the obtained material flow 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 less than 85%, it is combined through pipeline 29 and pipeline 14 and then recycled back to the hydrogenation reactor 1. The crude cyclohexene oxide product obtained at the bottom of the distillation tower is transported to the distillation tower 6 for distillation through pipeline 28; at the bottom of the distillation tower 6, polymers such as polycyclohexene are produced through pipeline 30, and light fractions containing a small amount of cyclohexene oxide are produced through pipeline 32. In each hydrogenation cycle, an average of 108.6 kg/h of pure cyclohexene oxide is produced through pipeline 31, with a GC purity of 99.5%. The yield of cyclohexene oxide relative to hydrogen peroxide is 97%. The mass ratio of co-produced cyclohexene oxide and cyclohexane is 2.2:1.

Claims (9)

1. A process for preparing epoxycyclohexane characterized by: taking mixed liquid after benzene hydrogenation reaction as a raw material, taking supported heteropolyacid salt as a catalyst, taking hydrogen peroxide with the mass concentration of 15% -60% as an oxygen source, and continuously preparing the epoxy cyclohexane under the inert atmosphere of 0.1-4 MPa;

The preparation method of the supported heteropolyacid salt catalyst comprises the following steps: dispersing metal carbonate MCO ₃ (+2 valence metal m= Mn, cu, co, ni) in deionized water, and adding dropwise an aqueous solution of H ₃XN₁₂O₄₈ (one or two of x= P, as; one or two of n= W, mo) to the resultant mixture; stirring the obtained mixture at room temperature for 2-8h, adding deionized water and carrier S, continuously stirring for 2-8h, precipitating, filtering, washing with deionized water and ethanol for three times respectively, and vacuum drying the obtained solid at 30-60deg.C for 1-8h to obtain M _nH_2-nXN₁₂O₄₈/S (one or more than two of M= Mn, cu, co, ni); (abbreviated as M-POM/S, wherein one or two of x= P, as; one or two of n= W, mo; one or more of m= Mn, cu, co, ni; 0.01< N <1.99, preferably 0.3. Ltoreq.n.ltoreq.1.8);

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

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

The epoxidation reaction temperature is 30-65 ℃;

The process flow is characterized by comprising the following process steps:

A) Preparing cyclohexene by benzene selective hydrogenation, and primarily treating the obtained selective hydrogenation mixed solution by water removal to obtain a reactant stream containing benzene, cyclohexene and cyclohexane;

B) Mixing the reactant flow obtained in the step A) with hydrogen peroxide and the supported phosphotungstic heteropolyacid salt catalyst in an epoxidation reactor, and directly carrying out epoxidation reaction in the reactor to prepare the cyclohexene oxide.

2. The method of claim 1, wherein the step of determining the position of the substrate comprises,

C) After the epoxidation reaction is finished, the cyclohexene oxide is separated and purified by rectification, and benzene, cyclohexane and unreacted cyclohexene are conveyed to a benzene selective hydrogenation reaction kettle again for selective hydrogenation and recycling.

3. The method according to claim 1 or 2, wherein the process of preparing cyclohexene by benzene selective hydrogenation comprises the steps of replacing the atmosphere in a hydrogenation reaction kettle with nitrogen, sequentially adding a selective hydrogenation catalyst, a dispersing agent, an additive and water to obtain catalyst reaction slurry, delivering hydrogen to the hydrogenation reaction kettle for replacement, filling the hydrogen to the reaction pressure, delivering benzene to the reaction kettle to obtain a benzene/water reactant stream, and carrying out selective hydrogenation reaction;

After the reaction is finished, the organic phase and the catalyst reaction slurry are separated in a phase separator, the catalyst reaction slurry is circularly conveyed to a hydrogenation reaction kettle, and the organic phase is the reactant flow (containing benzene, cyclohexene and cyclohexane) of the reaction mixture for preparing cyclohexene by benzene selective hydrogenation.

4. A process according to claim 1 or 3, characterized in that the starting material for the epoxidation is a reactant stream of a preliminary treatment for the removal of water from a reaction mixture for the preparation of cyclohexene by the selective hydrogenation of benzene; the primary water removal treatment is a water removal process of a reaction mixture subjected to selective hydrogenation; after water removal, the water percentage content in the reactant stream is <0.5%;

The cyclohexene content in the initially treated reactant stream is from 10% to 95%, preferably from 20% to 70%, by mass.

5. The method according to claim 1, wherein the selectivity of the epoxycyclohexane as a reactant can be adjusted by adjusting the addition amount of the metal M in the supported heteropolyacid salt catalyst M _nH_2-nXN₁₂O₄₈/S, and the value range of n is 0.01< n <1.99, preferably 0.3.ltoreq.n.ltoreq.1.8; the supported heteropolyacid salt catalyst can also be a mixture of catalysts with different metal M addition amounts, so as to adjust the selectivity of the reactant epoxycyclohexane, and the selectivity of the epoxycyclohexane is more than 95 percent.

6. The process according to claim 1, characterized in that cyclohexene epoxidation is carried out under an inert atmosphere at a pressure of 0.1 to 4MPa, preferably 0.5 to 2MPa; the inert atmosphere is one or two or more of nitrogen, argon, helium and the like; the mass concentration of the hydrogen peroxide oxygen source is 15% -60%, preferably 30% -50%.

7. The method according to claim 1 or 2, wherein after the reaction is finished, the epoxycyclohexane is separated and purified by rectification, and benzene, cyclohexane and unreacted cyclohexene are recycled by hydrogenation again;

After the single cyclohexene epoxidation reaction, the material flow containing water, benzene, cyclohexane and a small amount of cyclohexene can be directly recycled to the hydrogenation reaction kettle for hydrogenation circulation again after the cyclohexene oxide is separated by rectification.

8. The method according to claim 1 or 7, wherein after the epichlorohydrin is separated by more than 2 times of cyclic hydrogenation and epoxidation, the obtained material flow containing water, benzene, cyclohexane and a small amount of cyclohexene can be completely hydrogenated to co-produce cyclohexane when the mass percentage of the cyclohexane is more than 85%.

9. The method according to claim 1 or 5, wherein the supported heteropolyacid salt catalyst is a heterogeneous catalyst, and the method is easy to separate and circulate without the participation of additives, so that the large-scale continuous production of the cyclohexene oxide can be realized.