A continuous production process and device for triflurotoluene tower

Abstract

The application discloses a continuous production process and equipment for a trifluoromethylbenzene tower, and belongs to the field of organic fluorine chemistry. The production process comprises the following steps: S1: continuously feeding trichloromethylbenzene and hydrogen fluoride into a tower reactor connected with a heat exchanger circulating cooling system in a reverse direction, so that a three-stage continuous fluorination reaction occurs in the tower reactor to obtain crude trifluoromethylbenzene, and unreacted hydrogen fluoride is separated into liquid at the top of the tower and then flows back into the tower reactor; S2: the crude trifluoromethylbenzene obtained in the reaction is subjected to nitrogen bubbling in a bubble tower, and then is continuously distilled in a rectifying tower to obtain finished trifluoromethylbenzene; and S3: byproduct hydrogen chloride generated in the fluorination reaction is introduced into a hydrochloric acid tank to obtain hydrochloric acid, and the content of hydrofluoric acid in the hydrochloric acid is less than 1000 ppm. The method can greatly improve the utilization rate of raw material hydrogen fluoride, improve the purity of byproduct hydrochloric acid, reduce the generation amount of waste acid, avoid the sharp change of pressure in the reaction process, and realize large-scale, continuous, stable and safe production of trifluoromethylbenzene.

Description

Technical Field

[0001] This invention relates to the field of organofluorine chemistry, and more specifically, to a continuous tower-type production process and equipment for trifluorotoluene. Background Technology

[0002] Trifluorotoluene, with the molecular formula C6H5CF3 and a molecular weight of approximately 146.12, has a melting point of -29.1℃ and a boiling point of 104℃. It is insoluble in water but miscible with alcohols, acetone, benzene, carbon tetrachloride, diethyl ether, and hexane. Trifluorotoluene products are widely used as basic organic chemical raw materials in pesticides, pharmaceuticals, and new electronic materials. It is an intermediate in the preparation of herbicides such as fluroxypyr, flurfluthrin, and pyrifluquinazon, and is also an important intermediate in many pharmaceuticals. With the continuous development of these industries, the demand for trifluorotoluene is also continuously increasing.

[0003] Industrially, trifluorotoluene is produced through two methods: a high-temperature gas-phase method in the presence of a catalyst and a liquid-phase fluorination reaction in the presence of a catalyst. However, the liquid-phase fluorination reaction results in lower product purity and yield, and the utilization rate of hydrogen fluoride feedstock is low, with excess hydrogen fluoride difficult to recover, leading to serious resource waste and environmental pollution. The high-temperature gas-phase method offers significantly higher product yields, but the reaction temperature is as high as 300-500℃, which existing equipment generally cannot meet. Furthermore, current synthesis processes typically suffer from large hazardous waste emissions, high safety risks, and low economic efficiency.

[0004] To address the aforementioned issues, there are four domestic patents related to the production of trifluorotoluene. Among them, Chinese patent application CN201010622092.9, filed on December 31, 2010, provides a method for preparing a benzyl fluoride organic compound; Chinese patent application CN202011316214.1, filed on November 22, 2020, provides a method for preparing trifluorotoluene; and Chinese patent CN202111563841.X, filed on December 20, 2021, provides a titanium-based acidic ionic liquid, its preparation method, and its application. All three patents report processes for preparing trifluorotoluene, although... The prepared trifluorotoluene has high purity, but all three patents use an intermittent batch process, which requires a large equipment area, poses high safety risks, and has an unsatisfactory hydrogen fluoride utilization rate. In addition, there are problems such as excessive waste liquid that needs to be treated and low yield. To solve the above problems, Chinese patent application filed on January 24, 2024, with publication number CN117964597A, discloses a method for preparing fluoroethylene carbonate. This patent uses microchannels to prepare trifluorotoluene, but the method is limited by the characteristics of microchannel technology, and its production scale is small, making it difficult to meet the needs of large-scale industrial production.

[0005] In summary, existing literature has not fundamentally solved the problem of safe, reliable, large-scale, continuous production of high-quality trifluorotoluene. Therefore, it is imperative to provide a method for large-scale, continuous production of trifluorotoluene. Summary of the Invention

[0006] To address the problems existing in the prior art, the first objective of this invention is to provide a continuous trifluorotoluene production process using a tower, which can solve the problems of long preparation processes, large floor space requirements, and environmental unfriendliness. The second objective is to provide equipment for a continuous trifluorotoluene production process using a tower, which can achieve continuous production of trifluorotoluene, and the reaction exothermics of the device are kept constant, which can comprehensively improve the safety level of production.

[0007] To solve the above problems, the present invention adopts the following technical solution.

[0008] A continuous tower-type production process for trifluorotoluene includes the following preparation steps: S1: Fluorination process: Trichlorotoluene and hydrogen fluoride are continuously fed in counter-current manner into a tower reactor connected to a heat exchanger and circulating cooling system. A three-stage continuous fluorination reaction occurs in the tower reactor to obtain crude trichlorotoluene. Unreacted hydrogen fluoride is liquefied and refluxed into the tower reactor at the top of the tower through gas-liquid separation. S2: Distillation process: The crude trifluorotoluene obtained from the reaction enters the bubble column for nitrogen bubbling, and then enters the distillation column for continuous distillation to obtain the finished trifluorotoluene product with a purity of over 99%. S3: Acid formation process: Hydrogen chloride, a byproduct of the fluorination reaction, enters the hydrochloric acid tank to obtain hydrochloric acid.

[0009] Furthermore, the mass ratio of trichlorotoluene to hydrogen fluoride per unit time is ≥3.15:1, preferably 3.15-3.34:1.

[0010] Furthermore, the reaction temperature inside the tower reactor is 100-210℃, preferably 100-190℃.

[0011] Furthermore, the pressure inside the tower reactor is 1.5-5.0 MPa.

[0012] Furthermore, the condensation temperature of the heat exchanger circulating cooling system is -5 to 5°C, preferably -5 to 0°C.

[0013] Furthermore, the crude trifluorotoluene obtained from the reaction is bubbled in a bubbling tower with a nitrogen bubbling pressure of 0.2-2.0 MPa. After the crude trifluorotoluene is bubbled in the bubbling tower with nitrogen, the pressure drops to 0.1-1.0 MPa.

[0014] The present invention also provides equipment for the above-mentioned continuous production process of trifluorotoluene in a tower, including a tower reactor and a heat exchanger circulating cooling system disposed at the top of the tower reactor and connected thereto. The tower reactor has feed ports at both its lower and upper ends, which are respectively connected to a liquefied hydrogen fluoride storage tank and a trichlorotoluene tank. The lower end of the tower reactor has a discharge port with a collection valve, which is connected in sequence to a bubbling tower, a crude product storage tank, a distillation tower, and a distillation cooler via pipelines. The discharge port of the heat exchanger circulating cooling system is connected in sequence to a hydrochloric acid tank, a receiving tank, and several alkali absorption towers via pipelines. The upper end of the bubbling tower has a gas discharge port, which is connected to the receiving tank via a pipeline. The lower end of the bubbling tower is connected to a nitrogen tank.

[0015] Furthermore, submersible pumps are installed between the feed inlet of the tower reactor and the liquefied hydrogen fluoride storage tank and the trichlorotoluene tank, and a fluorination transfer pump is installed between the crude product storage tank and the distillation column; a compressor is installed between the outlet of the heat exchanger circulating cooling system and the hydrochloric acid tank.

[0016] Furthermore, the preferred preparation steps are as follows: Step 1): Trichlorotoluene, the raw material, is pumped from the trichlorotoluene tank to the upper feed port of the fluorination reaction tower via a submersible pump. Hydrogen fluoride, the raw material, is pumped from the liquefied hydrogen fluoride storage tank through a dedicated hydrogen fluoride pipeline to the lower feed port of the fluorination reaction tower. The mass ratio of trichlorotoluene to hydrogen fluoride per unit time is ≥3.15:1. The two materials are flushed and efficiently mixed in the fluorination reaction tower, resulting in a three-stage fluorine-chlorine exchange reaction. The pressure inside the fluorination tower is controlled at 1.5-5.0 MPa, and the reactor temperature is raised to 100-210 ℃. The circulating cooling system of the tower top heat exchanger is turned on, and the condenser power is adjusted to control the temperature to -5 to 5℃, so that the unreacted hydrogen fluoride is condensed through the circulating cooling system of the tower top heat exchanger. The condensed hydrogen fluoride is then returned to the reaction tower to continue participating in the reaction.

[0017] Step 2): After the feed operation stabilizes, liquid appears at the bottom of the fluorination reaction tower. Open the product collection valve and transport the product to the bubbling tower via pipeline. Introduce nitrogen gas at a pressure of 0.2-2.0 MPa at the bottom of the bubbling tower. The product after nitrogen bubbling enters the crude product storage tank. The crude product, trifluorotoluene, is pumped from the crude product storage tank into the rectification tower for continuous distillation via the fluorination transfer pump. The vapor is condensed in the rectification tower and rectification condenser to obtain trifluorotoluene. At atmospheric pressure, the fraction at 102±0.5 °C is collected.

[0018] Step 3): The byproduct hydrogen chloride is pumped into the hydrochloric acid tank via a compressor or directly pressurized to prepare 31% hydrochloric acid. The hydrofluoric acid content in the hydrochloric acid is <1000ppm. The tail gas generated in the hydrochloric acid tank and the gas generated by bubbling in Step 2 are fed into a receiving tank to generate waste hydrochloric acid. The hydrogen fluoride content in the waste hydrochloric acid generated here is <15%, and after cooling and recovering the hydrogen fluoride, the amount of waste acid is less than 5% of the amount of hydrochloric acid in the hydrochloric acid tank. A small amount of tail gas is discharged into the air after being cleaned by the first, second, and third stage alkaline absorption towers to meet emission standards.

[0019] The delivery pressure of trichlorotoluene and the inlet pressure of hydrogen fluoride are basically the same, with an error of about 0.1 MPa.

[0020] The trifluorotoluene product produced by this invention is tested according to the analytical method described in "T / ZZB 1726-2020 Trifluorotoluene". The main content of trifluorotoluene can reach more than 99%, and the content of single impurities is <0.2%.

[0021] Compared with the prior art, the advantages of this invention are: I. The overall process of this solution has advantages such as high fluorine atom utilization rate, high by-product quality, high safety, stable product quality, low energy consumption, low emissions of waste gas, wastewater, and solid waste, and high economic benefits. This process can significantly improve the utilization rate of raw material hydrogen fluoride, and the content of trifluorotoluene obtained can reach over 99%, with the content of a single impurity controlled below 0.2%, meeting the needs of the high-end market.

[0022] Second, this solution generates less waste, especially waste acid, which is generated at less than 5% of that generated by batch processes. This significantly reduces environmental pressure and aligns with the development concept of green chemistry.

[0023] Third, the continuous and compact process flow of this scheme solves the problems of large equipment footprint and difficulty in hydrogen fluoride recovery in previous preparation methods; in addition, it avoids drastic pressure changes during the reaction process in batch processes, and realizes large-scale, continuous, stable and safe production of trifluorotoluene. Attached Figure Description

[0024] Figure 1 A simplified diagram of the continuous trifluorotoluene production process in Example 1. Attached image description:

[0026] 1. Trichlorotoluene tank, 2. Liquefied hydrogen fluoride storage tank, 3. Submersible pump, 4. Tower reactor, 5. Heat exchanger circulating cooling system, 6. Bubbling tower, 7. Hydrochloric acid tank, 8. Crude product storage tank, 9. Fluoride transfer pump, 10. Distillation tower, 11. Distillation cooler, 12. Receiving tank. Detailed Implementation

[0027] Example 1:

[0028] Reaction apparatus such as Figure 1 As shown, the production equipment includes a tower reactor 4 and a heat exchanger circulating cooling system 5 located at the top of the tower reactor 4 and connected to it. The tower reactor 4 has feeding ports at both the lower and upper ends, which are respectively connected to a liquefied hydrogen fluoride storage tank 2 and a trichlorotoluene tank 1. The lower end of the tower reactor 4 has a discharge port with a collection valve, which is connected in sequence to a bubbling tower 6, a crude product storage tank 8, a distillation tower 10, and a distillation cooler 11 via pipelines. The discharge port of the heat exchanger circulating cooling system 5 is connected in sequence to a hydrochloric acid tank 7, a receiving tank 12, and several alkali absorption towers via pipelines. The upper end of the bubbling tower 6 has a gas discharge port, which is connected to the receiving tank 12 via a pipeline. The lower end of the bubbling tower 6 is connected to a nitrogen tank.

[0029] Submersible pumps 3 are installed between the feed inlet of the tower reactor 4 and the liquefied hydrogen fluoride storage tank 2 and the trichlorotoluene tank 1. A fluorination transfer pump 9 is installed between the crude product storage tank 8 and the distillation column 10. A compressor is installed between the outlet of the heat exchanger circulating cooling system 5 and the hydrochloric acid tank 7.

[0030] The reaction steps are as follows: Step 1): Trichlorotoluene, the raw material, is pumped into the top feed port of the tower reactor 4 via submersible pump 3 at a flow rate of 6.70 kg / min and a pressure of 1.5 MPa. Hydrogen fluoride, the raw material, is pumped into the bottom feed port of the tower reactor 4 via submersible pump 3 at a flow rate of 2.05 kg / min and a pressure of 1.5 MPa. The fluorination temperature is 100℃. The circulating cooling system 5 of the heat exchanger at the top of the tower is turned on, and ice-salt water is used for cooling to -5 to 0℃ to cool any unreacted hydrogen fluoride, which is then refluxed back into the tower to continue participating in the reaction.

[0031] Step 2): After the feed operation stabilizes, liquid appears at the bottom of tower reactor 4. Open the product collection valve and transport the product through the pipeline to bubble column 6. Introduce nitrogen gas at a flow rate of 1.0 m³ / s into the lower end of bubble column 6. 3 The pressure is 0.2 MPa. The product after nitrogen bubbling enters the crude product storage tank 8. The crude product, trifluorotoluene, is pumped from the crude product storage tank 8 into the distillation column 10 for continuous atmospheric distillation (0.101 MPa) via the fluorination transfer pump 9. The vapor is condensed in the distillation column 10 and the distillation cooler 11, and the fraction with a boiling point of 102 ± 0.5 °C is collected; this fraction is the target product. The above continuous preparation of trifluorotoluene operated for 24 hours, yielding 6.64 tons of finished trifluorotoluene, with a yield of 92%. Testing showed that the trifluorotoluene content was >99.3%, and the single impurity was <0.2%.

[0032] Step 3): The hydrogen chloride byproduct of the fluorination reaction is pumped into hydrochloric acid tank 7 via a compressor to prepare hydrochloric acid with a mass concentration of 31%. The tail gas from hydrochloric acid tank 7 and the gas discharged from bubble column 6 are fed into receiving tank 12 together. The generated gas is absorbed by 1-3 stage alkali absorption towers and then discharged into the air. The above steps, when operated continuously, produce 15.9 tons of hydrochloric acid as a byproduct, with a hydrofluoric acid content of <1000ppm.

[0033] Example 2:

[0034] The reaction apparatus in this embodiment is the same as that in Embodiment 1, and the reaction steps are as follows: Step 1): Trichlorotoluene, the raw material, is pumped into the top feed port of the tower reactor 4 via submersible pump 3 at a flow rate of 13.4 kg / min and a pressure of 3.0 MPa. Hydrogen fluoride, the raw material, is pumped into the bottom feed port of the tower reactor 4 via submersible pump 3 at a flow rate of 4.10 kg / min and a pressure of 3.0 MPa. The fluorination temperature is 150 ℃. The circulating cooling system 5 of the heat exchanger at the top of the tower is turned on, and ice-salt water is used for cooling to -5 to 0 ℃. Unreacted hydrogen fluoride is cooled and refluxed into the tower to continue participating in the reaction.

[0035] Step 2): After the feed operation stabilizes, liquid appears at the bottom of tower reactor 4. Open the product collection valve and transport the product through the pipeline to bubble column 6. Introduce nitrogen gas at a flow rate of 2.0 m / s² into the lower end of bubble column 6. 3 The product, after being bubbled with nitrogen, enters the crude product storage tank 8 to obtain crude trifluorotoluene. The crude trifluorotoluene is then pumped from the crude product storage tank 8 into the distillation column 10 via the fluorination transfer pump 9. Continuous distillation is performed at atmospheric pressure (0.101 MPa). The vapor is condensed in the distillation column 10 and the distillation cooler 11, and the fraction with a boiling point of 102 ± 0.5 °C is collected; this fraction is the target product. After 24 hours of continuous trifluorotoluene production, 13.57 tons of finished trifluorotoluene were obtained, with a yield of 94%. Testing showed that the trifluorotoluene content in the target product was >99.2%, and the content of any single impurity was <0.2%.

[0036] Step 3): The hydrogen chloride byproduct of the fluorination reaction is pumped into hydrochloric acid tank 7 via a compressor to prepare 30% hydrochloric acid. The tail gas from hydrochloric acid tank 7 and the gas discharged from bubble column 6 are both fed into receiving tank 12, and then absorbed by 1-3 stage alkali absorption towers before being discharged into the air. The above steps, operating continuously, produce 32.5 tons of hydrochloric acid as a byproduct, with a hydrofluoric acid content of <1000ppm.

[0037] Example 3:

[0038] The reaction apparatus in this embodiment is the same as that in Embodiment 1, and the reaction steps are as follows: Step 1): Trichlorotoluene, the raw material, is pumped into the top feed port of the tower reactor 4 via submersible pump 3 at a flow rate of 20.1 kg / min and a pressure of 4.5 MPa. Hydrogen fluoride, the raw material, is pumped into the bottom feed port of the tower reactor 4 via submersible pump 3 at a flow rate of 6.3 kg / min and a pressure of 4.5 MPa. The fluorination temperature is 190 °C. The circulating cooling system 5 of the top heat exchanger is started, and ice-salt water is used for cooling to -5 to 0 °C. Unreacted hydrogen fluoride is cooled and refluxed into the tower to continue participating in the reaction.

[0039] Step 2): After the feed operation stabilizes, liquid appears at the bottom of tower reactor 4. Open the product collection valve and transport the product through the pipeline to bubble column 6. Introduce nitrogen gas at a flow rate of 2.0 m / s² into the lower end of bubble column 6. 3 The pressure is 1.5 MPa. The product, after being bubbled with nitrogen, enters the crude product storage tank 8. The crude product, trifluorotoluene, is pumped from the crude product storage tank 8 into the distillation column 10 for continuous atmospheric distillation (0.101 MPa) via the fluorination transfer pump 9. The vapor is condensed in the distillation column 10 and the distillation cooler 11, and the fraction with a boiling point of 102 ± 0.5 °C is collected; this fraction is the target product. The above continuous preparation of trifluorotoluene operated for 24 hours, yielding 20.77 tons of finished trifluorotoluene, with a yield of 96%. Testing showed that the trifluorotoluene content was >99.2%, and the single impurity was <0.2%.

[0040] Step 3): The hydrogen chloride byproduct of the fluorination reaction is pumped into hydrochloric acid tank 7 via a compressor to prepare 30% hydrochloric acid. The tail gas from hydrochloric acid tank 7 and the gas discharged from bubble column 6 are fed into receiving tank 12 together. The generated gas is then discharged into the air after being washed by 1-3 stage alkali absorption towers. The above steps, when operated continuously, produce 49.8 tons of hydrochloric acid byproduct, of which the hydrofluoric acid content is <1000ppm.

[0041] Example 4:

[0042] The reaction apparatus in this embodiment is the same as that in Embodiment 1, and the reaction steps are as follows: Step 1): Trichlorotoluene, the raw material, is pumped into the top feed port of the tower reactor 4 via submersible pump 3 at a flow rate of 23.4 kg / min and a pressure of 5.0 MPa. Hydrogen fluoride, the raw material, is pumped into the bottom feed port of the tower reactor 4 via submersible pump 3 at a flow rate of 7.0 kg / min and a pressure of 5.0 MPa. The fluorination temperature is 210 ℃. The circulating cooling system 5 of the top heat exchanger is started, and ice-salt water is used for cooling to -5 to 0 ℃. Unreacted hydrogen fluoride is cooled and refluxed into the tower to continue participating in the reaction.

[0043] Step 2): After the feed operation stabilizes, liquid appears at the bottom of tower reactor 4. Open the product collection valve and transport the product through the pipeline to bubble column 6. Introduce nitrogen gas at a flow rate of 2.0 m / s² into the lower end of bubble column 6. 3The pressure is 2.0 MPa. The product, after being bubbled with nitrogen, enters the crude product storage tank 8. The crude product, trifluorotoluene, is pumped from the crude product storage tank 8 into the distillation column 10 for continuous atmospheric distillation (0.101 MPa) via the fluorination transfer pump 9. The vapor is condensed in the distillation column 10 and the distillation cooler 11, and the fraction with a boiling point of 102 ± 0.5 °C is collected; this fraction is the target product. The above continuous preparation of trifluorotoluene operated for 24 hours, yielding 22.84 tons of finished trifluorotoluene, with a yield of 95%. Testing showed that the trifluorotoluene content was >99.0%, and the single impurity was <0.2%.

[0044] Step 3): The hydrogen chloride byproduct of the fluorination reaction is pumped into hydrochloric acid tank 7 via a compressor to prepare 30% hydrochloric acid. The tail gas from hydrochloric acid tank 7 and the gas discharged from bubble column 6 are fed into receiving tank 12 together. The generated gas is then discharged into the air after being washed by 1-3 stage alkali absorption towers. The above steps, when operated continuously, produce 54.7 tons of hydrochloric acid byproduct, of which the hydrofluoric acid content is <1000ppm.

[0045] Comparative Example 1: A method for preparing trichlorotoluene involves adding 4200L of trichlorotoluene and 3kg of iron powder to a fluorination reactor. After confirming the brine is normal, 1900kg of hydrogen fluoride is added. For the initial addition, the amount of hydrogen fluoride can be increased to 2000kg, while other parameters remain unchanged. After adding the materials, the reactor is closed, and stirring is started. The frequency converter is adjusted to 30Hz, and stirring is performed for 10 minutes. After observing no abnormalities, a small amount of steam is introduced to slowly raise the temperature, reaching 20℃ in 2-3 hours. At 20℃, the steam is turned off, and the pressure is increased to 11kg before depressurization begins. The pressure is controlled and balanced at 14-15kg. When the temperature reaches 10-25℃, the fluorination reaction is in a relatively fast stage. Depending on the depressurization rate, the steam can be reduced or shut off for a period of time to ensure stable depressurization. The first batch of fluorination reaction samples are taken after 1 hour and sent to the analysis laboratory for sample retention to determine the peak time of difluoride. Under normal conditions, the pressure is maintained for 0.5-1 hour before sampling, with the endpoint being a difluoride concentration of less than 0.5-1%. After the reaction is completed, when the temperature is around 40℃, the lower valve of the pressure relief tank is closed, and the reaction vessel is shut off. Open the pressure relief valve slowly, releasing pressure until it reaches zero within one hour, while maintaining the temperature at 40℃-50℃. After pressure relief, close the pressure relief tank's upper valve and open the bypass valve and air compressor valve to begin purging the hydrogen fluoride inside the reactor, maintaining the temperature at 40℃-50℃. During purging, compressed gas will be present in the pipeline, and frost will form on the outer wall of the pipeline. Purge until the frost is gone, maintaining this temperature for 0.5-1 hour. The total purging time is approximately 2 hours. After purging, pre-fill the reactor with 500-800 kg of clean water. 100 kg of soda ash was dissolved by direct gas, then cooled to room temperature and set aside. Once ready, the soda ash was transferred to the steaming kettle. After the transfer was completed, direct gas was turned on and mixed for 2-3 minutes. A sample was taken from the alkali inlet or hand hole to measure the pH to 8-9. Steaming was then started. Ten minutes after discharge, a second pH test was taken, which was considered normal at 7-8. If the pH was less than 7, the alkali was adjusted to meet the standard, and steaming was continued until no oil droplets remained. After steaming, the trifluorotoluene was discharged into a distillation column for distillation. The fraction with a boiling point of 102±0.5 ℃ was collected, yielding 3896 kg of trifluorotoluene with a purity of 99.2%.

[0046] Test Example 1: The content and yield of trifluorotoluene in the final products of Examples 1-4 and Comparative Example 1, as well as the amount of waste acid generated and waste liquid treated during the experiment, were detected. The results are shown in Table 1.

[0047] ; As can be seen from the data in Table 1, the preparation methods involved in Examples 1-4 not only achieved high purity and yield, but also did not generate a large amount of waste acid and waste liquid, which significantly reduced the burden of subsequent waste liquid treatment and was more in line with the concept of green chemistry and sustainable development.

[0048] The above embodiments describe the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0049] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A continuous production process for trifluorotoluene using a tower-type process, characterized in that: The preparation steps include the following: S1: Fluorination process: Trichlorotoluene and hydrogen fluoride are continuously fed in countercurrent direction into a tower reactor (4) connected to a heat exchanger circulation cooling system (5) at the top. A three-stage continuous fluorination reaction occurs in the tower reactor (4) to obtain crude trichlorotoluene. Unreacted hydrogen fluoride is liquefied and refluxed into the tower reactor (4) at the top of the tower through gas-liquid separation. S2: Distillation process: The crude trifluorotoluene obtained from the reaction enters the bubble column (6) for nitrogen bubbling, and then enters the distillation column (10) for continuous distillation to obtain the finished trifluorotoluene product; S3: Acid formation process: Hydrogen chloride, a byproduct of the fluorination reaction, enters the hydrochloric acid tank (4) to obtain hydrochloric acid.

2. The continuous production process of trifluorotoluene using a tower as described in claim 1, characterized in that: The mass ratio of trichlorotoluene to hydrogen fluoride fed per unit time is ≥3.15:

1.

3. The continuous production process of trifluorotoluene using a tower as described in claim 1, characterized in that: The reaction temperature inside the tower reactor (4) is 100-210℃.

4. The continuous production process of trifluorotoluene using a tower as described in claim 1, characterized in that: The internal pressure of the tower reactor (4) is 1.5-5.0 MPa.

5. The continuous production process of trifluorotoluene using a tower as described in claim 1, characterized in that: The condensation temperature of the heat exchanger circulating cooling system (5) is -5-5℃.

6. The continuous production process of trifluorotoluene using a tower as described in claim 1, characterized in that: The crude trifluorotoluene obtained from the reaction is fed into a bubbling tower (6) for nitrogen bubbling at a pressure of 0.2-2.0 MPa. After passing through the bubbling tower, the pressure of the crude trifluorotoluene drops to 0.1-1.0 MPa.

7. The equipment for a continuous trifluorotoluene production process according to any one of claims 1-6, characterized in that: The system includes a tower reactor (4) and a heat exchanger circulating cooling system (5) located at the top of the tower reactor (4) and connected to it. The tower reactor (4) has a feeding port at both the bottom and top, and is connected to a liquefied hydrogen fluoride storage tank (2) and a trichlorotoluene tank (1), respectively. The bottom of the tower reactor (4) has an outlet with a collection valve, and the outlet is connected to a bubbling tower (6), a crude product storage tank (8), a distillation tower (10), and a distillation cooler (11) in sequence through pipes. The outlet of the heat exchanger circulating cooling system (5) is connected to a hydrochloric acid tank (7), a receiving tank (12), and several alkali absorption towers in sequence through pipes. The top of the bubbling tower (6) has a gas outlet, which is connected to the receiving tank (12) through pipes. The bottom of the bubbling tower (6) is connected to a nitrogen tank.

8. The equipment for a continuous trifluorotoluene production process using a tower as described in claim 7, characterized in that: Submersible pumps (3) are provided between the feed inlet of the tower reactor (4) and the liquefied hydrogen fluoride storage tank (2) and the trichlorotoluene tank (1). A fluorination transfer pump (9) is provided between the crude product storage tank (8) and the distillation tower (10). A compressor is provided between the outlet of the heat exchanger circulating cooling system (5) and the hydrochloric acid tank (7).

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