Reaction device for producing epsilon-caprolactone from cyclohexanone

Abstract

The utility model relates to the field of chemical equipment, in particular to a reaction device for producing epsilon-caprolactone from cyclohexanone, which comprises a mixing tank, a dehydrating tower, an oxidation reactor and a separating tank which are sequentially arranged, the mixing tank is connected to the dehydrating tower through a pipeline and a pump, a discharge port at the lower part of the dehydrating tower is connected to the oxidation reactor, and a discharge port at the lower part of the separating tank is connected to the separating tank. The oxidation reactor is further provided with a gas inlet, an organic acid feed port, a cyclohexanone feed port and a crude product discharge port, the crude product discharge port is connected to the separation tank, and an epsilon-caprolactone discharge port is formed in the bottom of the separation tank. According to the utility model, the peroxidation reaction of acid and the oxidation reaction of cyclohexanone are designed in one reactor, and different reaction conditions can be controlled in different zones, so that peroxide immediately flows downwards to react with cyclohexanone after being generated, the existence time of unstable peroxide is shortened to the greatest extent, and the safety is greatly improved. The whole production process is high in conversion rate, stable in operation, high in product yield and capable of realizing continuous production.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical equipment and relates to a method for producing cyclohexanone. e -Reaction apparatus for caprolactone. Background Art

[0002] e -Caprolactone is an important raw material for the synthesis of polycaprolactone (PCL). PCL has good flexibility and excellent processability, and the ester bond in its molecular structure has good hydrolysis properties, which also makes PCL widely concerned in the field of biodegradable polymers. e -Caprolactone synthesis process is relatively complex, and the production equipment and production safety requirements are high, which restricts its large-scale industrial production. e -Caprolactone basically relies on imports, which has restricted related domestic industries.

[0003] The existing process is to prepare the product by reacting cyclohexanone with percarboxylic acid. e -caprolactone, hydrogen peroxide is used to oxidize organic acid to prepare peroxy acid in a stirred tank, and after a certain amount of peroxide is stored, the principle of Baeyer-Villiger oxidation reaction is used to react cyclohexanone with percarboxylic acid. However, during the concentration and separation of peroxy acid, a high concentration of explosive peroxide will be produced, and the water in the reaction system cannot be removed, which will cause a great deal of explosion. e -Hydrolysis of caprolactone greatly limits the industrial application of this process. Summary of the invention

[0004] The utility model provides a method for producing cyclohexanone e -The reaction device for caprolactone integrates the preparation of peroxyacid and the oxidation of cyclohexanone into the oxidation reactor, shortening the existence time of peroxide, greatly improving safety and making production more stable.

[0005] The technical solution of the utility model is a method for producing cyclohexanone e The reaction device of -caprolactone comprises a mixing tank, a dehydration tower, an oxidation reactor and a separation tank which are arranged in sequence, wherein the mixing tank is connected to the dehydration tower through a pipeline and a pump, the lower discharge port of the dehydration tower is connected to the oxidation reactor, the oxidation reactor is also provided with an air inlet, an organic acid feed port, a cyclohexanone feed port and a crude product discharge port, the crude product discharge port is connected to the separation tank, and the bottom of the separation tank is e -Caprolactone outlet.

[0006] Furthermore, the dehydration tower is provided with a dehydration tower circulation material port and a dehydration tower feed port, which are connected by a pipeline and a pump, and a heater is also provided on the pipeline.

[0007] Furthermore, the mixing tank is connected to the pipeline at the front end of the heater through the pipeline and the pump.

[0008] Furthermore, a gas phase discharge port is also provided at the upper portion of the dehydration tower.

[0009] Furthermore, a heat exchange pipe is provided inside the oxidation reactor, and circulating water is introduced into the heat exchange pipe.

[0010] Furthermore, the heat exchange pipe of the oxidation reactor is divided into an upper heat exchange pipe and a lower heat exchange pipe, which are independent of each other to achieve zoned temperature control.

[0011] Furthermore, the air inlet of the oxidation reactor, the organic acid feed inlet and the dehydration tower feed inlet are all arranged at the upper part thereof, the cyclohexanone feed inlet is located in the middle part thereof, and the crude product discharge port is located at the lower part thereof.

[0012] Furthermore, a distributor is provided at the lower part of the cyclohexanone feed port of the oxidation reactor.

[0013] Furthermore, a gas phase outlet is provided at the top of the separation tank, and a vacuum pump is connected to the outside of the separation tank through a pipeline.

[0014] The utility model has the following beneficial effects:

[0015] The utility model first mixes the oxidant, stabilizer and water-carrying agent in a mixing tank in proportion and then enters the dehydration tower for concentration, thereby avoiding the risk of decomposition of the oxidant during the dehydration process. The dehydrated material reacts with the organic acid in the oxidation reactor to produce peracid, and the peracid then reacts with cyclohexanone in the oxidation reactor, thereby shortening the existence time of unstable peroxides to the greatest extent and greatly improving safety. Nitrogen is introduced during the reaction, and under the driving effect of the nitrogen flow, on the one hand, it can ensure that the material flows in a predetermined direction, and on the other hand, it accelerates the flow of the material, reduces the residence time of the product, and can bring out the generated water in time, effectively reducing product decomposition; the material in the oxidation reactor enters the separation tank, and the water in the reaction process can be brought out as soon as possible by vacuuming, and the obtained e -Caprolactone further enters the subsequent distillation process.

[0016] The device was used to prepare e -caprolactone, the entire production process has high conversion rate, stable operation, high product yield, and can be produced continuously. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the utility model. DETAILED DESCRIPTION

[0018] The following will be combined with the embodiments and attached Figure 1 The embodiments of the present invention are described in detail, but those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention.

[0019] like Figure 1 As shown, the utility model provides a method for producing cyclohexanone e The reaction device of -caprolactone comprises a mixing tank 1, a dehydration tower 2, an oxidation reactor 3 and a separation tank 4 which are arranged in sequence, wherein the mixing tank is connected to the dehydration tower through a pipeline and a pump, the lower discharge port of the dehydration tower is connected to the oxidation reactor, the oxidation reactor is also provided with an air inlet 3-1, an organic acid feed port 3-2, a cyclohexanone feed port 3-3 and a crude product discharge port 3-4, the crude product discharge port is connected to the separation tank, and the bottom of the separation tank is e -Caprolactone outlet.

[0020] In some embodiments, the dehydration tower is provided with a dehydration tower circulation material port 2-1 and a dehydration tower feed port 2-2, which are connected by a pipeline and a pump, and a heater 5 is also provided on the pipeline.

[0021] In some embodiments, the mixing tank is connected to the pipe at the front end of the heater through a pipe and a pump. The mixing tank is also provided with a liquid level meter, a stirring paddle, etc. The oxidant, stabilizer, and water-carrying agent are added to the mixing tank in proportion and uniformly mixed.

[0022] In some embodiments, a gas phase discharge port 2-3 is further provided at the top of the dehydration tower. The dehydration tower is filled with fillers, which may be metal corrugated fillers, plastic orifice fillers or ceramic particle fillers. The oxidant and the water-carrying agent are dehydrated in the dehydration tower by azeotropic action. The fillers can enhance the mass transfer process and prevent excessive local concentration. At the same time, the addition of stabilizers can effectively inhibit the decomposition of intermediate products and target products, ensuring the safety of the entire process.

[0023] In some embodiments, a heat exchange pipe is further provided inside the oxidation reactor, preferably a heat exchange structure consisting of 5 to 10 heat exchange pipes, and circulating water is passed into the heat exchange pipe.

[0024] In some embodiments, the heat exchange pipe of the oxidation reactor is divided into an upper heat exchange pipe and a lower heat exchange pipe, which are independent of each other and not internally connected, so as to realize zoned temperature control. The cooling medium goes through the tube side, and the reaction materials go through the shell side. The peroxidation of organic acids and the oxidation reaction of cyclohexanone can be integrated into the same reaction equipment. The peroxy acid after the peroxidation of organic acids reacts with cyclohexanone immediately, which shortens the existence time of unstable peroxides to the greatest extent and greatly improves safety. When the device is working normally, the medium of the upper heat exchange pipe is hot water, and the temperature of the hot water is controlled to ensure the smooth progress of the reaction, preferably controlled at 60-90°C; the medium of the lower heat exchange pipe is cooling water, which can remove the heat generated by the reaction in time to reduce e -Decomposition of caprolactone, the temperature is preferably controlled at 30-50°C.

[0025] In some embodiments, the air inlet, organic acid feed inlet and dehydration tower feed inlet of the oxidation reactor are all arranged at the upper part thereof, the cyclohexanone feed inlet is located in the middle part thereof, and the crude product discharge port is located at the lower part thereof.

[0026] In some embodiments, a distributor 3-5 is further provided at the lower part of the cyclohexanone feed port of the oxidation reactor. The distributor divides the oxidation reactor into two upper and lower areas for loading different catalysts. The circulating water inlet of the upper heat exchange pipe is located above the distributor, and the outlet is located at the upper part of the oxidation reactor; the circulating water inlet of the lower heat exchange pipe is located at the lower part of the oxidation reactor, and the outlet is located below the distributor. The upper part of the oxidizer is loaded with a solid acid catalyst, where the organic acid and the dehydrated oxidant generate organic acid peroxides, which flow to the lower part of the oxidizer and react with the cyclohexanone flowing out of the distributor to generate e -Caprolactone.

[0027] In some embodiments, a gas phase outlet is provided on the top of the separation tank, and a vacuum pump is connected to the outside of the separation tank through a pipeline; under a high vacuum environment, water in the product is quickly evaporated to avoid e -Hydrolysis of caprolactone.

[0028] During the specific operation, the oxidant, stabilizer and water-carrying agent are added to the mixing tank according to a certain proportion, and after being mixed evenly, they are transported to the inlet of the heater through a material pump and a pipeline. After being heated by the heater, the materials enter the dehydration tower, and the materials flow from top to bottom in the dehydration tower, and are divided into fine droplets by the fillers in the tower. In this process, the water and water-carrying agent in the raw materials are gasified and extracted from the gas phase discharge port 2-3 provided at the upper part of the dehydration tower, and the concentrated oxidant and stabilizer enter the bottom of the dehydration tower, and then are transported to the heater through a pump and a pipeline for cyclic heating, and part of the materials are transported to the upper part of the oxidation reactor through the discharge port below the dehydration tower. The concentrated oxidant and stabilizer are mixed with the organic acid entering the organic acid feed port 3-2 at the upper part of the oxidation reactor, react under the action of the catalyst to generate peroxide, and flow downward under the driving effect of the nitrogen flow coming in from the oxidation reactor air inlet 3-1. Cyclohexanone is added from the cyclohexanone feed port 3-3 and enters the oxidation reactor evenly through the distributor, where it mixes with the peroxy organic acid flowing downward and reacts under the action of the catalyst at the bottom of the oxidation reactor to generate e The generated crude product, driven by the nitrogen flow, enters the top of the separation tank through the crude product outlet 3-4, and the water and nitrogen in the product are extracted from the system through the gas phase outlet provided at the top of the separation tank. e -Caprolactone falls into the bottom of the separation tank, and the bottom of the separation tank is e -The caprolactone outlet enters the subsequent distillation process.

[0029] The above embodiments are only for illustrating the technical ideas and features of the utility model, and the contents are only preferred embodiments of the utility model, but the protection scope of the utility model is not limited thereto. Within the technical scope disclosed by the utility model, equivalent changes or improvements based on the technical solution and utility model concept of the utility model should be included in the protection scope of the utility model.

Claims

1. A method of producing cyclohexanone ε - a reaction device for caprolactone, characterized in that: The invention comprises a mixing tank, a dehydration tower, an oxidation reactor and a separation tank which are arranged in sequence, wherein the mixing tank is connected to the dehydration tower through a pipeline and a pump, the lower discharge port of the dehydration tower is connected to the oxidation reactor, the oxidation reactor is also provided with an air inlet, an organic acid feed port, a cyclohexanone feed port and a crude product discharge port, the crude product discharge port is connected to the separation tank, and the bottom of the separation tank is ε -Caprolactone outlet.

2. The device according to claim 1, characterized in that: The dehydration tower is provided with a dehydration tower circulation material port and a dehydration tower feed port, which are connected by a pipeline and a pump, and a heater is also provided on the pipeline.

3. The device according to claim 2, characterized in that: The mixing tank is connected to the pipeline in front of the heater through pipelines and pumps.

4. The device according to claim 1, characterized in that: A gas phase discharge port is also provided at the top of the dehydration tower.

5. The device according to any one of claims 1 to 4, characterized in that: A heat exchange pipe is also arranged inside the oxidation reactor, and circulating water is introduced into the heat exchange pipe.

6. The device according to claim 5, characterized in that: The heat exchange pipe of the oxidation reactor is divided into an upper heat exchange pipe and a lower heat exchange pipe, which are independent of each other to achieve zoned temperature control.

7. The device according to claim 1, characterized in that: The air inlet of the oxidation reactor, the organic acid feed inlet and the dehydration tower feed inlet are all arranged at the upper part thereof, the cyclohexanone feed inlet is located in the middle part thereof, and the crude product discharge port is located at the lower part thereof.

8. The device according to claim 1, characterized in that: A distributor is also provided at the lower part of the cyclohexanone feed port of the oxidation reactor.

9. The device according to claim 1, characterized in that: A gas phase outlet is provided on the top of the separation tank, and a vacuum pump is connected to the outside of the separation tank through a pipeline.

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