Production method and system of caprolactone

Abstract

The invention provides a caprolactone production method and system. The caprolactone production method comprises the following steps: S1, continuously adding carboxylic acid, a catalyst, a stabilizer and hydrogen peroxide into a supergravity reactor; vaporizing a water-carrying agent, and continuously adding the vaporized water-carrying agent into the supergravity reactor; s2, carboxylic acid and hydrogen peroxide react in the supergravity reactor to generate peroxycarboxylic acid, peroxycarboxylic acid reaction liquid containing a water-carrying agent, a catalyst and a stabilizer enters a dehydration device to be subjected to heating dehydration separation, azeotrope with water of the vaporized water-carrying agent is discharged and then condensed, layered and separated, and the separated water-carrying agent circularly flows back to the dehydration device and continuously moves out with water; s3, continuously discharging the separated peroxycarboxylic acid reaction liquid from the dehydration device, dewatering one part of the peroxycarboxylic acid reaction liquid, feeding the dewatered peroxycarboxylic acid reaction liquid into a caprolactone reactor, and circularly feeding the other part of the peroxycarboxylic acid reaction liquid into a supergravity reactor for continuous reaction; and S4, simultaneously adding cyclohexanone into the caprolactone reactor, reacting to obtain a crude caprolactone product, and rectifying and separating the crude caprolactone to obtain the caprolactone.

Description

Technical Field

[0001] The present invention relates to the field of new materials, and particularly to a production method and system for caprolactone monomer. Background Art

[0002] ε-Caprolactone, with the chemical formula C 6 H 10 O 2 , is a colorless liquid with a density of 1.0693, a boiling point of 98 - 99 °C (1.33 kPa), a melting point of about -5 °C, and is soluble in water, ethanol, and benzene. ε-Caprolactone is a widely used chemical intermediate. ε-Caprolactone can undergo a ring-opening reaction catalyzed by various compounds or copolymerize with other monomers to synthesize polymers such as polycaprolactone (PCL), polycaprolactone polyol (PCL polyol), and polycaprolactone polyurethane. PCL resin has good shape memory properties, low-temperature flexibility, and hydrolysis resistance, is non-toxic, harmless, and 100% biodegradable. It is an important polymer material with broad application prospects in fields such as absorbable surgical sutures, facial filling materials, tissue engineering, artificial skin, medical dressings, resin bandages, fracture fixation, and dental impression materials. Polycaprolactone polyol (PCL polyol) obtained by ε-caprolactone under the initiation of polyol, and then reacted with diisocyanate to obtain polycaprolactone-based polyurethane, is widely used in fields such as coatings and adhesives. In addition, ε-caprolactone can also be used as a strong solvent to dissolve many polymer resins and shows good solubility for some poorly soluble resins. For example, it can dissolve chlorinated polyolefin resins and "ESTANE" polyurethane resins.

[0003] Currently, the main industrial production method for ε-caprolactone at home and abroad is the cyclohexanone oxidation method, using organic peroxyacids as oxidants, which has the advantages of strong oxidation ability, high product yield, and rich raw material sources. CN103570667B discloses a method for continuously preparing ε-caprolactone, in which a peroxycarboxylic acid solution and cyclohexanone are added together to the first stirred reaction kettle of 2 - 8 series-connected stirred reaction kettles, and then the reaction materials overflow from kettle to kettle until a solution containing ε-caprolactone is obtained in the last kettle. The conversion rate of cyclohexanone is high, and the selectivity of ε-caprolactone is high. However, this process has a long reaction time and complex process equipment.

[0004] Therefore, it is necessary to provide a new production method and system for caprolactone, with simple process equipment, low energy consumption, and high conversion rate and selectivity. Summary of the Invention

[0005] The object of the present invention is to provide a production method and system for caprolactone, with simple process equipment, low energy consumption, and high reaction conversion rate and selectivity.

[0006] To achieve the above object, the technical solution adopted by the present invention is to provide a production method of caprolactone, which includes the following steps: S1: Continuously add carboxylic acid, catalyst and stabilizer to a high-gravity reactor through a first pipeline; continuously add hydrogen peroxide to the high-gravity reactor through a second pipeline; vaporize the water-carrying agent and continuously add it to the high-gravity reactor through a third pipeline; S2: Under the action of the catalyst and stabilizer, the carboxylic acid and hydrogen peroxide react in the high-gravity reactor to generate peroxycarboxylic acid. The peroxycarboxylic acid reaction solution containing the water-carrying agent, catalyst and stabilizer enters a dehydration device for heating dehydration separation. The azeotrope of the vaporized water-carrying agent and water is discharged and then condensed and separated. The separated water-carrying agent is recycled and refluxed to the dehydration device, and water is continuously removed; S3: The separated peroxycarboxylic acid reaction solution is continuously discharged from the dehydration device. After part of the water is removed, it is sent to a caprolactone reactor, and the other part is recycled into the high-gravity reactor for continuous reaction; S4: Cyclohexanone is added to the caprolactone reactor at the same time, and the reaction obtains a crude caprolactone product. The crude caprolactone is separated by distillation to obtain caprolactone.

[0007] Further, the hydrogen peroxide in step S1 is hydrogen peroxide with a mass percentage of 35-70%, the catalyst is one or more of boric acid, sulfuric acid, nitric acid and nicotinic acid, the stabilizer is one or more of 8-hydroxyquinoline, tributyl phosphate, picolinic acid and 2-methylpyridine, the carboxylic acid is acetic acid, propionic acid or butyric acid, and the water-carrying agent is one or more of ethyl acetate, ethyl propionate, ethyl butyrate, propyl propionate and butyl acetate.

[0008] Further, carboxylic acid: water-carrying agent: stabilizer: catalyst: hydrogen peroxide (molar ratio) = (921-961):(218-238):(0.8-1.2):(3.72-7.601):(205-341).

[0009] Further, after adding all the materials to the high-gravity reactor in step S1, evacuate to -0.07-0.1 Mpa and control the reaction solution temperature to 50-68 °C.

[0010] Further, the reaction temperature in step S4 is 40-70 °C and the reaction time is 3-5 hours.

[0011] Further, the molar ratio of peroxycarboxylic acid to cyclohexanone in step S4 is: peroxycarboxylic acid: cyclohexanone = (1-1.2):1.

[0012] Further, the volume ratio of the reaction solution sent to the caprolactone reactor after dehydration by acid anhydride to the reaction solution recycled into the high-gravity reactor in step S3 is 1:(1-20).

[0013] To achieve the above object, the present invention also provides a system for the production method of the above-mentioned caprolactone, which includes a high-gravity reactor, a vaporizer, a dehydration device, a condenser, a separator, a caprolactone reactor, and a rectification column. The outlet of the vaporizer is connected to the high-gravity reactor, the outlet of the high-gravity reactor is respectively connected to the dehydration device and the condenser, the outlet of the dehydration device is respectively connected to the condenser and the microchannel reactor, the outlet of the condenser is connected to the separator, the outlet of the separator is connected to the dehydration device, and the outlet of the microchannel reactor is connected to the rectification column; carboxylic acid, catalyst, stabilizer, and hydrogen peroxide react in the high-gravity reactor to form a peroxycarboxylic acid reaction solution, and a part of the entrainer vapor is incorporated into the peroxycarboxylic acid reaction solution and enters the dehydration device together, and a part of the entrainer vapor directly enters the condenser with water; the dehydration device includes a top dehydration tower and a bottom reboiler. The peroxycarboxylic acid reaction solution in the high-gravity reactor enters the dehydration tower after coming out. The reboiler heats the peroxycarboxylic acid reaction solution in the dehydration tower to discharge the azeotrope of the entrainer and water from the top and then enters the condenser. The entrainer vapor is condensed in the condenser and then enters the separator for separation. The lower-layer water is discharged, and the upper-layer entrainer is refluxed to the dehydration tower; the peroxycarboxylic acid reaction solution in the dehydration tower is pumped out from the bottom of the dehydration tower, and a part of it enters the caprolactone reactor to react with cyclohexanone, and the other part is circulated into the high-gravity reactor; the crude caprolactone product obtained from the reaction in the caprolactone reactor enters the rectification column for rectification to obtain caprolactone.

[0014] Further, the high-gravity reactor includes a liquid-phase inlet, a liquid-phase outlet, a liquid distributor, a packing layer, a rotor, a rotating shaft, a gas-phase inlet, and a gas-phase outlet. Carboxylic acid, catalyst, and stabilizer continuously enter the liquid distributor from the liquid-phase inlet through the first pipeline, and hydrogen peroxide continuously enters the liquid distributor from another liquid-phase inlet through the second pipeline. The liquid is evenly distributed on the packing layer through the liquid distributor. The outlet of the vaporizer is connected to the gas-phase inlet of the high-gravity reactor, and the vaporized entrainer enters the packing layer from the gas-phase inlet of the high-gravity reactor; the packing layer is made of a porous material and is used to increase the gas-liquid contact area. The rotor is fixed and drives the packing layer to rotate to simulate a high-gravity environment, and the rotating shaft supports and drives the rotor to rotate; the top gas-phase outlet of the high-gravity reactor is connected to the inlet of the condenser, and the entrainer vapor enters the condenser after coming out from the top gas-phase outlet of the high-gravity reactor. The bottom liquid-phase outlet of the high-gravity reactor is connected to the middle inlet of the dehydration tower, and the peroxycarboxylic acid reaction solution enters the dehydration tower from the middle inlet of the dehydration tower after coming out from the bottom liquid-phase outlet of the high-gravity reactor.

[0015] Further, the caprolactone reactor includes a microchannel reactor and a ripening device. The peroxycarboxylic acid reaction solution from the dehydration tower enters the microchannel reactor to react with cyclohexanone. The outlet of the microchannel reactor is connected to the inlet of the ripening device, and the outlet of the ripening device is connected to the inlet of the rectification tower. The reaction solution after reaction in the microchannel reactor enters the ripening device to continue the reaction, and the crude caprolactone obtained after the reaction in the ripening device enters the rectification tower for rectification.

[0016] The present invention has the following beneficial effects compared with the prior art: The production method and system of caprolactone provided by the present invention oxidize carboxylic acid and hydrogen peroxide in a rotating packed bed reactor in the presence of a catalyst and a stabilizer to obtain peroxycarboxylic acid. During the reaction process, the constantly vaporized water-carrying agent is used for azeotropic water removal, which can accelerate the removal of water from the reaction system. Then, peroxycarboxylic acid reacts with cyclohexanone to obtain caprolactone. At the same time, the peroxycarboxylic acid reaction solution is continuously recycled into the rotating packed bed reactor for sufficient material contact reaction, thereby improving the conversion rate and utilization rate of hydrogen peroxide, making the conversion rate of hydrogen peroxide greater than 99% and the utilization rate greater than 90%. In a rotating packed bed environment, both the molecular diffusion between molecules of different sizes and the mass transfer process between phases are much faster than those in a conventional gravitational field. The microscopic mixing and mass transfer processes are greatly enhanced, and the production efficiency per unit equipment volume can be significantly improved. Moreover, the water-carrying agent vaporized during the reaction takes away water, which is beneficial to the forward reaction, ensures the smooth progress of the reaction, reduces the reaction time, and avoids the decomposition of peroxycarboxylic acid caused by too long reaction time. At the same time, the coupling technology of rotating packed bed reaction and rectification strengthens the reaction mass transfer, improves the reaction conversion rate and selectivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is the process flow chart of the production of caprolactone in the embodiment of the present invention; Figure 2 is the schematic diagram of the production system of caprolactone in the embodiment of the present invention; Figure 3 is the schematic diagram of the production system of peroxycarboxylic acid in the embodiment of the present invention.

[0018] Reference numerals in the drawings: 1 - carboxylic acid, 2 - catalyst, 3 - stabilizer, 4 - water-carrying agent, 5 - hydrogen peroxide, 6 - vaporizer, 7 - rotating packed bed reactor, 8 - dehydration tower, 9 - reboiler, 10 - condenser, 11 - separator, 12 - caprolactone reactor, 13 - rectification tower, 71 - first pipeline, 72 - second pipeline, 73 - third pipeline, 89 - dehydration device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The present invention will be further described below with reference to the drawings and embodiments.

[0020] Please refer to Figure 1 , the method for producing caprolactone provided by the present invention includes the following steps: S1: Continuously add carboxylic acid, catalyst and stabilizer into the high gravity reactor through the first pipeline; continuously add hydrogen peroxide into the high gravity reactor through the second pipeline; vaporize the water-carrying agent and continuously add it into the high gravity reactor through the third pipeline. Preferably, the hydrogen peroxide is hydrogen peroxide with a mass percentage of 35 - 70%, more preferably hydrogen peroxide with a mass percentage of 50%. The catalyst is one or more of boric acid, sulfuric acid, nitric acid and nicotinic acid. The stabilizer is one or more of 8-hydroxyquinoline, tributyl phosphate, picolinic acid and 2-methylpyridine. The carboxylic acid is acetic acid, propionic acid or butyric acid. The water-carrying agent is one or more of ethyl acetate, ethyl propionate, ethyl butyrate, propyl propionate and butyl acetate. In a preferred embodiment, carboxylic acid: water-carrying agent: stabilizer: catalyst: hydrogen peroxide (molar ratio) = (921 - 961):(218 - 238):(0.8 - 1.2):(3.72 - 7.601):(205 - 341). After adding all the materials into the high gravity reactor, evacuate to -0.07 - 0.1 Mpa and control the temperature of the reaction solution to 50 - 68 °C.

[0021] The high gravity reactor will simulate a high gravity environment. So-called high gravity refers to the force that substances receive in an environment much larger than the earth's gravitational acceleration (9.8 m / s 2 ). In a high gravity environment, the molecular diffusion between molecules of different sizes and the mass transfer process between phases are much faster than those in a conventional gravity field. The micro-mixing and mass transfer processes are greatly enhanced, and the production efficiency per unit equipment volume is increased by 1 - 2 orders of magnitude.

[0022] S2: Under the action of the catalyst and stabilizer, the carboxylic acid and hydrogen peroxide react in the high gravity reactor to generate peroxycarboxylic acid (Product 1). The peroxycarboxylic acid reaction solution containing the water-carrying agent, catalyst and stabilizer enters the dehydration device for heating dehydration separation. The azeotrope of the vaporized water-carrying agent and water is discharged and then condensed and separated by stratification. The separated water-carrying agent is recycled back to the dehydration device and continuously removes water. The presence of water in the reaction system will hinder the forward progress of the reaction. Water must be continuously removed during the reaction to ensure the smooth progress of the reaction. However, if the reaction time is too long, the peroxycarboxylic acid will decompose. The vaporized water-carrying agent is conducive to the rapid removal of water, reducing the reaction time and thus avoiding the decomposition of peroxycarboxylic acid.

[0023] S3: The separated peroxycarboxylic acid reaction solution is continuously discharged from the dehydration device. After removing water, a part of it is sent to the caprolactone reactor, and the other part is recycled into the high gravity reactor for continuous reaction. Specifically, the peroxycarboxylic acid reaction solution is dehydrated by acid anhydride. The volume ratio of the reaction solution sent to the caprolactone reactor to the reaction solution recycled into the high gravity reactor is preferably 1:(1 - 20). Continuously recycle the peroxycarboxylic acid reaction solution into the high gravity reactor for sufficient material contact reaction, so as to improve the conversion rate and utilization rate of hydrogen peroxide.

[0024] S4: Cyclohexanone is added to the caprolactone reactor, and the reaction yields a crude caprolactone product. After the crude caprolactone is separated by distillation, caprolactone is obtained. Preferably, the molar ratio of peroxycarboxylic acid to cyclohexanone is: peroxycarboxylic acid: cyclohexanone = (1 - 1.2): 1, the reaction temperature is 40 - 70 °C, and the reaction time is 3.5 - 4.5 hours.

[0025] Please refer to Figure 2 and Figure 3 , To implement the above production method of caprolactone, the present invention provides a caprolactone production system, including a rotating packed bed reactor 7, a vaporizer 6, a dehydration device 89, a condenser 10, a separator 11, a caprolactone reactor 12, and a distillation column 13. The top outlet of the vaporizer 6 is connected to the rotating packed bed reactor 7. The outlet of the rotating packed bed reactor 7 is respectively connected to the dehydration device 89 and the condenser 10. The outlet of the dehydration device 89 is respectively connected to the condenser 10 and the caprolactone reactor 12. The outlet of the condenser 10 is connected to the separator 11. The outlet of the separator 11 is connected to the dehydration device 89. The outlet of the caprolactone reactor 12 is connected to the distillation column 13.

[0026] Carboxylic acid 1, catalyst 2, stabilizer 3, and hydrogen peroxide 5 react in the rotating packed bed reactor 7 to form a peroxycarboxylic acid reaction solution. Part of the entrainer 4 vapor is incorporated into the peroxycarboxylic acid reaction solution and enters the dehydration device 89 together. Part of the entrainer 4 vapor directly enters the condenser 10 with water.

[0027] The dehydration device 89 includes a top dehydration tower 8 and a bottom reboiler 9. The peroxycarboxylic acid reaction solution from the rotating packed bed reactor 7 enters the dehydration tower 8. The reboiler 9 heats the peroxycarboxylic acid reaction solution in the dehydration tower 8 to discharge the azeotrope of the entrainer and water from the top and enter the condenser 10. The entrainer vapor is condensed in the condenser 10 and enters the separator 11 for separation. The lower layer of water is discharged, and the upper layer of entrainer is refluxed to the dehydration tower 8, continuously circulating to continuously discharge the water in the reaction system.

[0028] The peroxycarboxylic acid reaction solution in the dehydration tower 8 is pumped out from the bottom of the dehydration tower, and a part of it enters the caprolactone reactor 12 to react with cyclohexanone, and the other part is recycled to the rotating packed bed reactor 7; the crude caprolactone product obtained from the reaction in the caprolactone reactor 12 enters the distillation column 13 for distillation to obtain caprolactone (product 2).

[0029] The supergravity reactor 7 includes a liquid-phase feed port, a liquid-phase discharge port, a liquid distributor, a packing layer, a rotor, a rotating shaft, a gas-phase feed port, and a gas-phase discharge port. Carboxylic acid 1, catalyst 2, and stabilizer 3 continuously enter the liquid distributor from the liquid-phase feed port through the first pipeline 71. Hydrogen peroxide 5 continuously enters the liquid distributor from another liquid-phase feed port through the second pipeline 72. The reaction liquid is evenly distributed on the packing layer by the liquid distributor. The discharge port of the vaporizer 6 is connected to the gas-phase feed port of the supergravity reactor 7. The water-carrying agent 4 enters the vaporizer 6 from the bottom feed port of the vaporizer 6 and is vaporized. The vaporized water-carrying agent 4 enters the packing layer from the gas-phase feed port of the supergravity reactor 7. The packing layer is made of a porous material and is used to increase the gas-liquid contact area. The rotor is fixed and drives the packing layer to rotate to simulate a supergravity environment. The rotating shaft supports and drives the rotor to rotate. The top gas-phase discharge port of the supergravity reactor 7 is connected to the inlet of the condenser. A part of the water-carrying agent 4 vapor directly enters the condenser 10 after coming out from the top gas-phase discharge port of the supergravity reactor 7. The bottom liquid-phase discharge port of the supergravity reactor 7 is connected to the middle feed port of the dehydration tower 8. The peroxycarboxylic acid reaction liquid comes out from the bottom liquid-phase discharge port of the supergravity reactor 7 and enters the dehydration tower 8 from the middle feed port of the dehydration tower 8.

[0030] In a specific embodiment, the caprolactone reactor 12 includes a microchannel reactor and a ripening device. The peroxycarboxylic acid reaction liquid coming out from the dehydration tower enters the microchannel reactor to react with cyclohexanone. The discharge port of the microchannel reactor is connected to the feed port of the ripening device. The discharge port of the ripening device is connected to the feed port of the rectification tower. The reaction liquid after reaction in the microchannel reactor enters the ripening device to continue the reaction. The crude caprolactone obtained after the reaction in the ripening device enters the rectification tower for rectification separation to obtain caprolactone. In other embodiments, a tubular reactor can also be used to replace the microchannel reactor.

[0031] Example 1 In this example, acetic acid: ethyl acetate: 8-hydroxyquinoline: boric acid: 35% hydrogen peroxide solution materials are put into the supergravity reactor according to a molar ratio of 921:218:0.8:3.72:205. The vacuum is pumped to -0.07 Mpa. The temperature of the reaction liquid is 50 °C, and the reaction time is 3 hours. The mass percentage concentration of the obtained peracetic acid is 11%.

[0032] Example 2 In this example, propionic acid: propyl propionate: tributyl phosphate: sulfuric acid: 43% hydrogen peroxide solution materials are put into the supergravity reactor according to a molar ratio of 931:223:0.9:4.69:239. The vacuum is pumped to -0.03 Mpa. The temperature of the reaction liquid is 55 °C, and the reaction time is 3.5 hours. The mass percentage concentration of the obtained perpropionic acid is 11.6%.

[0033] Example 3 In this example, propionic acid: ethyl propionate: 2-methylpyridine: boric acid: 50% hydrogen peroxide solution are fed into a high-gravity reactor in a molar ratio of 941:228:1:5.66:273. The reactor is evacuated to 0.01 Mpa, the reaction solution temperature is 60 °C, and the reaction time is 4 hours. The mass percentage concentration of peroxypropionic acid obtained is 17%.

[0034] Example 4 In this example, butyric acid: ethyl butyrate: pyridinecarboxylic acid: nitric acid: 45% hydrogen peroxide solution are fed into a high-gravity reactor in a molar ratio of 951:233:1.1:6.63:307. The reactor is evacuated to 0.05 Mpa, the reaction solution temperature is 64 °C, and the reaction time is 4.5 hours. The mass percentage concentration of peroxybutyric acid obtained is 20%.

[0035] Example 5 In this example, acetic acid: butyl acetate: 2-methylpyridine: nicotinic acid: 50% hydrogen peroxide solution are fed into a high-gravity reactor in a molar ratio of 961:238:1.2:7.601:341. The reactor is evacuated to 0.1 Mpa, the reaction solution temperature is 68 °C, and the reaction time is 5 hours. The mass percentage concentration of peroxyacetic acid obtained is 22%.

[0036]

[0037] Example 6 In this example, in step S4, the molar ratio of peroxycarboxylic acid to cyclohexanone is: peroxycarboxylic acid: cyclohexanone = 1:1, the reaction temperature is 40 °C, and the reaction time is 3 hours.

[0038] Example 7 In this example, in step S4, the molar ratio of peroxycarboxylic acid to cyclohexanone is: peroxycarboxylic acid: cyclohexanone = 1.2:1, the reaction temperature is 70 °C, and the reaction time is 4 hours.

[0039] Example 8 In this example, in step S4, the molar ratio of peroxycarboxylic acid to cyclohexanone is: peroxycarboxylic acid: cyclohexanone = 1.1:1, the reaction temperature is 55 °C, and the reaction time is 5 hours.

[0040]

[0041] In summary, the present invention obtains peroxycarboxylic acid by carrying out an oxidation reaction in a high-gravity reactor. During the reaction process, the continuous azeotropic water-carrying of the vaporized water-carrying agent can accelerate the removal of water from the reaction system. Then, the peroxycarboxylic acid reacts with cyclohexanone to obtain caprolactone. At the same time, the peroxycarboxylic acid reaction solution is continuously recycled into the high-gravity reactor for sufficient material contact reaction, thereby improving the conversion rate and utilization rate of hydrogen peroxide. At the same time, the coupling technology of high-gravity reaction and rectification strengthens the mass transfer of the reaction and improves the reaction conversion rate and selectivity of cyclohexanone. The present invention realizes industrial continuous production, simplifies the process equipment, improves the production efficiency, and reduces the production cost.

[0042] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be defined by the claims.

Claims

1. A method for producing caprolactone, characterized in that: The steps include: S1: continuously adding carboxylic acid, catalyst and stabilizer into the high gravity reactor through the first pipeline; continuously adding hydrogen peroxide into the high gravity reactor through the second pipeline; The water-carrying agent is vaporized and continuously added into the supergravity reactor through the third pipeline; S2: under the action of the catalyst and the stabilizer, the carboxylic acid and the hydrogen peroxide react in the supergravity reactor to generate peroxycarboxylic acid, the peroxycarboxylic acid reaction liquid containing the water-carrying agent, the catalyst and the stabilizer enters the dehydration device for heating, dehydration and separation, the azeotrope of the vaporized water-carrying agent and water is discharged and condensed and separated by layers, and the separated water-carrying agent is circulated back to the dehydration device and continuously removed with water; S3: The separated peroxycarboxylic acid reaction liquid is continuously discharged from the dehydration device, a part of which is sent to the caprolactone reactor after dehydration, and the other part is circulated into the supergravity reactor to continue the reaction; S4: Cyclohexanone is added into the caprolactone reactor at the same time to react to obtain a crude caprolactone product, and the crude caprolactone is distilled and separated to obtain caprolactone.

2. The method for producing caprolactone according to claim 1, wherein: The hydrogen peroxide in step S1 is hydrogen peroxide with a mass percentage of 35-70%, the catalyst is one or more of boric acid, sulfuric acid, nitric acid and nicotinic acid, the stabilizer is one or more of 8-hydroxyquinoline, tributyl phosphate, pyridinecarboxylic acid and 2-methylpyridine, the carboxylic acid is acetic acid, propionic acid or butyric acid, and the water-carrying agent is one or more of ethyl acetate, ethyl propionate, ethyl butyrate, propyl propionate and butyl acetate.

3. The method for producing caprolactone according to claim 2, characterized in that Carboxylic acid: water-carrying agent: stabilizer: catalyst: hydrogen peroxide (molar ratio) = (921-961): (218-238): (0.8-1.2): (3.72-7.601): (205-341).

4. The method for producing caprolactone according to claim 1, wherein: In step S1, after all materials are added, the supergravity reactor is evacuated to -0.07-0.1Mpa, and the temperature of the reaction liquid is controlled to 50-68°C.

5. The method for producing caprolactone according to claim 1, wherein: The reaction temperature in step S4 is 40-70° C., and the reaction time is 3-5 hours.

6. The method for producing caprolactone according to claim 1, wherein: The molar ratio of peroxycarboxylic acid to cyclohexanone in step S4 is: peroxycarboxylic acid:cyclohexanone=(1-1.2):

1.

7. The method for producing caprolactone according to claim 1, wherein: The volume ratio of the reaction liquid sent to the caprolactone reactor after dehydration by anhydride in step S3 and the reaction liquid circulated into the supergravity reactor is 1: (1-20).

8. A system for the production method of caprolactone according to any one of claims 1 to 7, characterized in that: It comprises a supergravity reactor, a vaporizer, a dehydration device, a condenser, a stratifier, a caprolactone reactor and a distillation tower, wherein the discharge port of the vaporizer is connected to the supergravity reactor, the discharge port of the supergravity reactor is respectively connected to the dehydration device and the condenser, the discharge port of the dehydration device is respectively connected to the condenser and the microchannel reactor, the discharge port of the condenser is connected to the stratifier, the discharge port of the stratifier is connected to the dehydration device, and the discharge port of the microchannel reactor is connected to the distillation tower; Carboxylic acid, catalyst, stabilizer and hydrogen peroxide react in a supergravity reactor to form a peroxycarboxylic acid reaction liquid, part of the water-carrying steam is melted into the peroxycarboxylic acid reaction liquid and enters the dehydration device together, and part of the water-carrying steam directly enters the condenser with water; The dehydration device includes a top dehydration tower and a bottom reboiler. The peroxycarboxylic acid reaction liquid in the supergravity reactor enters the dehydration tower after coming out. The reboiler heats the peroxycarboxylic acid reaction liquid in the dehydration tower so that the azeotrope of the water-carrying agent and water is discharged from the top and then enters the condenser. The water-carrying agent steam is condensed in the condenser and then enters the separator for separation. The lower layer of water is discharged, and the upper layer of the water-carrying agent is refluxed to the dehydration tower. The peroxycarboxylic acid reaction liquid in the dehydration tower is pumped out from the bottom of the dehydration tower, and a part of it enters the caprolactone reactor to react with cyclohexanone, and the other part is circulated into the supergravity reactor; the crude caprolactone product obtained by the reaction in the caprolactone reactor enters the distillation tower for distillation to obtain caprolactone.

9. The system according to claim 8, characterized in that The high-gravity reactor comprises a liquid-phase feed port, a liquid-phase discharge port, a liquid distributor, a packing layer, a rotor, a rotating shaft, a gas-phase feed port and a gas-phase discharge port. Carboxylic acid, a catalyst and a stabilizer are continuously fed into the liquid distributor from the liquid-phase feed port through a first pipeline. Hydrogen peroxide is continuously fed into the liquid distributor from another liquid-phase feed port through a second pipeline. The liquid is evenly distributed in the packing layer through the liquid distributor. The discharge port of the vaporizer is connected to the gas-phase feed port of the high-gravity reactor. The vaporized water-carrying agent is fed into the packing layer from the gas-phase feed port of the high-gravity reactor. layer; the packing layer is made of porous material and is used to increase the gas-liquid contact area; the rotor is fixed and drives the packing layer to rotate to simulate the supergravity environment; the rotating shaft supports and drives the rotor to rotate; the top gas phase discharge port of the supergravity reactor is connected to the inlet of the condenser, and the water-containing steam enters the condenser after coming out of the top gas phase discharge port of the supergravity reactor; the bottom liquid phase discharge port of the supergravity reactor is connected to the middle feed port of the dehydration tower; the peroxycarboxylic acid reaction liquid enters the dehydration tower from the middle feed port of the dehydration tower after coming out of the bottom liquid phase discharge port of the supergravity reactor.

10. The system according to claim 8, characterized in that The caprolactone reactor comprises a microchannel reactor and a ripener. The peroxycarboxylic acid reaction liquid from the dehydration tower enters the microchannel reactor to react with cyclohexanone. The discharge port of the microchannel reactor is connected to the feed port of the ripener. The discharge port of the ripener is connected to the feed port of the distillation tower. The reaction liquid after the reaction in the microchannel reactor enters the ripener to continue the reaction. The crude caprolactone obtained after the reaction in the ripener enters the distillation tower for rectification.

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