Continuous rectification system for ethyl trifluoroacetate

Abstract

The utility model belongs to the technical field of rectification systems of chemicals, and particularly relates to a continuous rectification system for ethyl trifluoroacetate. The ethyl trifluoroacetate continuous rectification system comprises a first-stage rectification tower and a second-stage rectification tower, the tower top of the first-stage rectification tower is connected with a first-stage condenser, a gas outlet of the first-stage condenser is connected with a first-stage absorption device, a liquid outlet of the first-stage condenser is connected with an alcohol-containing substance receiving tank, and the alcohol-containing substance receiving tank is connected with a second-stage absorption device. The first-stage rectifying tower is connected with the second-stage rectifying tower, the tower top of the second-stage rectifying tower is connected with the second-stage condenser, a gas outlet of the second-stage condenser is connected with the first-stage absorption device, and a liquid outlet of the second-stage condenser is connected with the finished product receiving tank. The ethyl trifluoroacetate continuous rectification system provided by the utility model is easy to operate, the cost is reduced, the yield of rectified products is improved, and the process is environment-friendly.

Description

Technical Field

[0001] The utility model belongs to the technical field of distillation systems for chemical products, and in particular relates to a continuous distillation system for ethyl trifluoroacetate. Background Art

[0002] Ethyl trifluoroacetate is a fine chemical product with a density of 1.194 g / cm 3 , boiling point is 60-62℃, easily soluble in ethanol and ether, slightly soluble in water. Due to its fluorine-containing properties, it plays a key role in the fields of medicine and pesticides, especially in the production of fluorine-containing pesticides and pharmaceutical intermediates.

[0003] Ethyl trifluoroacetate is currently mainly prepared by the reaction of trifluoroacetyl chloride and ethanol. The crude product contains impurities such as ethanol, trifluoroacetyl chloride and hydrogen chloride. In the existing process, batch degassing and dealcoholization are first performed by intermittent distillation during the distillation process, and then the main fraction is distilled to finally obtain a high-purity ethyl trifluoroacetate product.

[0004] Patent CN110343043A discloses a purification process of ethyl trifluoroacetate, which removes impurities in crude ethyl trifluoroacetate (to remove most of the alcohol and a small amount of acid contained in the crude ethyl trifluoroacetate) by combining water washing, adsorption and distillation processes. Although a high-purity ethyl trifluoroacetate product can be obtained, the processing process is complicated, the efficiency is low, and the product cost is increased. Utility Model Content

[0005] The technical problem to be solved by the utility model is to overcome the above-mentioned defects in the prior art and provide a continuous distillation system for ethyl trifluoroacetate, which is easy to operate, reduces costs, improves the yield of the distilled product, and is environmentally friendly.

[0006] The utility model discloses a continuous distillation system for ethyl trifluoroacetate, comprising a primary distillation tower and a secondary distillation tower, wherein the top of the primary distillation tower is connected to a primary condenser, the gas outlet of the primary condenser is connected to a primary absorption device, the liquid outlet of the primary condenser is connected to an alcohol-containing receiving tank, the primary distillation tower is connected to a secondary distillation tower, the top of the secondary distillation tower is connected to a secondary condenser, the gas outlet of the secondary condenser is connected to a primary absorption device, and the liquid outlet of the secondary condenser is connected to a finished product receiving tank. The primary distillation tower is used for preliminarily separating impurities in the distillation crude product. The secondary distillation tower is used for further purifying the material from the primary distillation tower.

[0007] Preferably, the primary distillation tower is provided with a crude product liquid inlet and a reflux bottom liquid outlet.

[0008] Preferably, the crude product liquid inlet is connected to a crude distillation product feeding pump, and the crude distillation product feeding pump is connected to a crude product receiving tank.

[0009] Preferably, the reflux bottom liquid outlet is connected to a liquid conduction pump, and the liquid conduction pump is connected to the bottom of the secondary distillation tower.

[0010] Preferably, fillers are provided inside the primary distillation tower.

[0011] Preferably, the primary absorption device is connected to the secondary absorption device, and the secondary absorption device is connected to the tertiary absorption device.

[0012] Preferably, the liquid outlet of the secondary condenser is provided with a pipeline for reflux to the secondary distillation tower.

[0013] Preferably, the liquid outlet of the primary condenser is provided with a pipeline for reflux to the primary distillation tower.

[0014] Preferably, the crude product receiving tank is provided with a production device connecting pipe.

[0015] The utility model discloses a continuous distillation system for ethyl trifluoroacetate, wherein the crude product synthesized by the generating device is connected to the crude product receiving tank through the connecting pipe of the production device, the crude product receiving tank is connected to the primary distillation tower through the distillation crude product feeding pump, the primary distillation tower is connected to the primary condenser, the primary condenser is connected to the alcohol-containing receiving tank, and then the primary distillation tower body is provided with a crude product liquid inlet and a reflux bottom liquid outlet, and the packing adopts a tetrafluoroethylene packing, the crude product liquid inlet is located at the upper part of the tower body but keeps a distance from the reflux liquid nozzle, and the reflux bottom liquid outlet keeps a certain distance from the bottom of the kettle and the crude product liquid inlet (tower body height: reflux bottom liquid outlet is 1.5 meters, and the crude product liquid inlet is 2.5 meters, and the crude product liquid inlet ... Flow spray: crude product liquid inlet: reflux bottom liquid outlet is 10:9:8:3), a distributor (with distribution and liquid storage functions) is arranged at the bottom of the tower at the reflux bottom liquid outlet, the first-stage distillation tower is connected to the second-stage distillation tower through a liquid guide pump, the second-stage distillation tower is connected to the second-stage condenser, the second-stage condenser is connected to the finished product receiving tank, the tower packing adopts PTFE packing, the first-stage condenser and the second-stage condenser are respectively connected to the first-stage absorption device, micro-pressure check valves are arranged on the second-stage condenser and the first-stage absorption device, the first-stage absorption device is connected to the second-stage absorption device, and the second-stage absorption device is connected to the tertiary absorption device.

[0016] Compared with the prior art, the utility model has the following beneficial effects:

[0017] (1) The ethyl trifluoroacetate continuous distillation system of the utility model obtains a high-purity ethyl trifluoroacetate product by double-tower continuous distillation, which is simple to operate and highly efficient.

[0018] (2) The ethyl trifluoroacetate continuous distillation system of the utility model realizes continuous operation, has high utilization rate of intermediates, and saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the continuous distillation system of ethyl trifluoroacetate of the present invention.

[0020] In the figure: 1. primary distillation tower; 2. secondary distillation tower; 3. alcohol-containing receiving tank; 4. finished product receiving tank; 5. primary condenser; 6. secondary condenser; 7. liquid guide pump; 8. primary absorption device; 9. secondary absorption device; 10. tertiary absorption device; 11. crude product liquid inlet; 12. reflux bottom liquid outlet; 13. packing; 14. crude product receiving tank; 15. distillation crude product feeding pump; 16. production device connecting pipe. DETAILED DESCRIPTION

[0021] The utility model is further described below in conjunction with specific embodiments.

[0022] The primary distillation tower 1 and the secondary distillation tower 2 used in the following examples and comparative examples are all existing equipment, and their specific internal structures are not further limited. In addition, the primary absorption device 8, the secondary absorption device 9, and the tertiary absorption device 10 are all structural modes with condensation on the top and storage tanks on the bottom, and their specific internal structures are all existing equipment, and are not discussed in detail.

[0023] like Figure 1 As shown, the ethyl trifluoroacetate continuous distillation system of the utility model comprises a primary distillation tower 1 and a secondary distillation tower 2, the top of the primary distillation tower 1 is connected to a primary condenser 5, the gas outlet of the primary condenser 5 is connected to a primary absorption device 8, the liquid outlet of the primary condenser 5 is connected to an alcohol-containing receiving tank 3, the primary distillation tower 1 is connected to a secondary distillation tower 2, the top of the secondary distillation tower 2 is connected to a secondary condenser 6, the gas outlet of the secondary condenser 6 is connected to a primary absorption device 8, and the liquid outlet of the secondary condenser 6 is connected to a finished product receiving tank 4. The primary distillation tower 1 is used for preliminarily separating impurities in the distillation crude product. The secondary distillation tower 2 is used for further purifying the material from the primary distillation tower 1.

[0024] The primary distillation tower 1 is provided with a crude product liquid inlet 11 and a reflux bottom liquid outlet 12 .

[0025] The crude product liquid inlet 11 is connected to a crude distillation product feeding pump 15 , and the crude distillation product feeding pump 15 is connected to a crude product receiving tank 14 .

[0026] The reflux bottom liquid outlet 12 is connected to the liquid guiding pump 7 , and the liquid guiding pump 7 is connected to the bottom of the secondary distillation tower 2 .

[0027] The first-stage distillation tower 1 is provided with a packing 13 inside.

[0028] The primary absorption device 8 is connected to the secondary absorption device 9 , and the secondary absorption device 9 is connected to the tertiary absorption device 10 .

[0029] The liquid outlet of the secondary condenser 6 is provided with a pipeline for reflux to the secondary distillation tower 2 .

[0030] The liquid outlet of the primary condenser 5 is provided with a pipeline for reflux to the primary distillation tower 1 .

[0031] The crude product receiving tank 14 is provided with a production device connecting pipe 16 .

[0032] The utility model discloses a continuous distillation system for ethyl trifluoroacetate, wherein the crude product synthesized by the generating device is connected to the crude product receiving tank 14 through the production device connecting pipe 16, the crude product receiving tank is connected to the primary distillation tower 1 through the distillation crude product feeding pump 15, the primary distillation tower 1 is connected to the primary condenser 5, the primary condenser 5 is connected to the alcohol-containing receiving tank 3, and then the primary distillation tower body is provided with a crude product liquid inlet 11 and a reflux bottom liquid outlet 12, and then the packing 13 adopts a tetrafluoroethylene packing, the crude product liquid inlet 11 is located at the upper part of the tower body but keeps a distance from the reflux liquid nozzle, and the reflux bottom liquid outlet 12 keeps a certain distance from the bottom of the kettle and the crude product liquid inlet 11 (tower body height: reflux bottom liquid outlet 12). Flow spray: crude product liquid inlet 11: reflux bottom liquid outlet 12 is 10:9:8:3), a distributor (with distribution and liquid storage functions) is arranged at the lower part of the tower at the reflux bottom liquid outlet 12, the primary distillation tower 1 is connected to the secondary distillation tower 2 through a liquid guide pump 7, the secondary distillation tower 2 is connected to the secondary condenser 6, the secondary condenser 6 is connected to the finished product receiving tank 4, the tower packing adopts polytetrafluoroethylene packing, the primary condenser 5 and the secondary condenser 6 are respectively connected to the primary absorption device 8, micro-pressure check valves are arranged on the secondary condenser 6 and the primary absorption device 8, the primary absorption device 8 is connected to the secondary absorption device 9, and the secondary absorption device 9 is connected to the tertiary absorption device 10.

[0033] Specifically, the operation process of the ethyl trifluoroacetate continuous distillation system is as follows: the crude ethyl trifluoroacetate synthesized by the production device is continuously pumped into the crude product receiving tank 14 through the production device connecting pipe 16, and after reaching a certain liquid level, it is all introduced into the primary distillation tower 1 through the crude distillation product feeding pump 15, and the crude distillation product feeding pump 15 is turned off, and then the temperature of the tower bottom of the primary distillation tower 1 is set at 40-55°C for degassing treatment, and when the system pressure begins to be lower than the liquid seal pressure of the primary absorption device 8 and no bubbles are generated, dealcoholization treatment is carried out, and when the gas phase temperature reaches the range of 60-62°C and the alcohol content of the distilled component is less than 0.1%, the crude distillation product feeding pump 15 is turned on for continuous feeding and the liquid guide pump 7 is turned on to return part of the distillation tower to the distillation tower. The liquid is continuously pumped into the secondary distillation tower 2, and when the kettle of the secondary distillation tower 2 reaches the liquid level, the first and second continuous distillation is carried out, the kettle bottom temperatures of the first distillation tower 1 and the second distillation tower 2 are maintained at 75-85°C, and the reflux ratios are 25:1 / 4:1 respectively, and the first and second condensation circulating water temperatures are maintained at 2-8°C. The fore fraction and the main fraction are received by the alcohol-containing receiving tank 3 and the finished product receiving tank 4 respectively, and the gas phase is collected by the first absorption device 8, the second absorption device 9, and the tertiary absorption device 10. The kettle temperatures of the first absorption device 8 and the second absorption device 9 are 40-50°C, condensed at 5-10°C, and the kettle temperature of the tertiary absorption device 10 is condensed at 15-20°C. The purity of the final product is 99.95% as detected by GC.

[0034] Of course, the above contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of the embodiments of the present invention. The present invention is not limited to the above examples. Equal changes and improvements made by ordinary technicians in the technical field within the essential scope of the present invention should all fall within the scope of the patent coverage of the present invention.

Claims

1. A continuous distillation system for ethyl trifluoroacetate, characterized in that: The invention comprises a primary distillation tower (1) and a secondary distillation tower (2), wherein the top of the primary distillation tower (1) is connected to a primary condenser (5), the gas outlet of the primary condenser (5) is connected to a primary absorption device (8), the liquid outlet of the primary condenser (5) is connected to an alcohol-containing receiving tank (3), the primary distillation tower (1) is connected to a secondary distillation tower (2), the top of the secondary distillation tower (2) is connected to a secondary condenser (6), the gas outlet of the secondary condenser (6) is connected to the primary absorption device (8), and the liquid outlet of the secondary condenser (6) is connected to a finished product receiving tank (4).

2. The continuous distillation system of ethyl trifluoroacetate according to claim 1, characterized in that: The primary distillation tower (1) is provided with a crude product liquid inlet (11) and a reflux bottom liquid outlet (12).

3. The continuous distillation system of ethyl trifluoroacetate according to claim 2, characterized in that: The crude product liquid inlet (11) is connected to a crude distillation product feeding pump (15), and the crude distillation product feeding pump (15) is connected to a crude product receiving tank (14).

4. The continuous distillation system of ethyl trifluoroacetate according to claim 2, characterized in that: The reflux bottom liquid outlet (12) is connected to a liquid guiding pump (7), and the liquid guiding pump (7) is connected to the bottom of the secondary distillation tower (2).

5. The continuous distillation system of ethyl trifluoroacetate according to claim 1, characterized in that: The first-stage distillation tower (1) is provided with a filler (13) inside.

6. The continuous distillation system of ethyl trifluoroacetate according to claim 1, characterized in that: The primary absorption device (8) is connected to the secondary absorption device (9), and the secondary absorption device (9) is connected to the tertiary absorption device (10).

7. The continuous distillation system of ethyl trifluoroacetate according to claim 1, characterized in that: The liquid outlet of the secondary condenser (6) is provided with a pipeline for reflux to the secondary distillation tower (2).

8. The continuous distillation system of ethyl trifluoroacetate according to claim 1, characterized in that: The liquid outlet of the primary condenser (5) is provided with a pipeline for reflux to the primary distillation tower (1).

9. The continuous distillation system of ethyl trifluoroacetate according to claim 3, characterized in that: The crude product receiving tank (14) is provided with a production device connecting pipe (16).

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