Device and method for continuously removing trifluoromethanesulfonic acid bound water

Abstract

The invention relates to a device and a method for continuously removing trifluoromethanesulfonic acid bound water. The device comprises a water removal unit and a rectification unit, the water removal unit comprises an adsorption tower and a water removal tower, an anti-explosion heating assembly is fixedly installed in the adsorption tower, the tower is filled with a molecular sieve, and the adsorption tower is connected with the lower portion of the side face of the water removal tower through a bottom air outlet pipe; the water removal tower is a packed tower, and a gas distributor is mounted at the lower part of packing; the rectification unit comprises a rectification tower, a sulfuric acid storage tank and a trifluoromethanesulfonic acid storage tank, the top of the rectification tower is connected with a condenser through a pipeline, and an outlet of the condenser is connected with the top of the rectification tower and the trifluoromethanesulfonic acid storage tank through pipelines; the bottom of the rectifying tower is connected with a reboiler and a liquid-phase extraction pipe, and the liquid-phase extraction pipe is connected with a sulfuric acid storage tank; and a bottom liquid-phase outlet of the dewatering tower is connected with the upper part of the rectifying tower. According to the invention, the SO3 gas is used as a dewatering agent, and bound water in the trifluoromethanesulfonic acid is effectively removed through a gas-liquid reverse contact reaction, so that the yield and the purity of the trifluoromethanesulfonic acid are improved.

Description

Technical Field

[0001] The invention belongs to the field of fine chemicals, relates to a synthesis technology of fine pharmaceutical intermediates, and in particular to a device and a method for continuously removing trifluoromethanesulfonic acid bound water. Background Art

[0002] Trifluoromethanesulfonic acid is the strongest known organic acid. It is mainly used in pharmaceutical intermediates, ionic liquids, fluorinated surfactants, catalysts, etc. It is a raw material for manufacturing various practical compounds such as herbicides, antimicrobial agents, obesity drugs, and electrolytes in batteries. It can also be used as a component of cleaning gas with a very fast etching speed. Trifluoromethanesulfonic acid has broad application prospects. In my country's petrochemical industry, due to environmental protection considerations, perchloric acid is gradually eliminated, and trifluoromethanesulfonic acid and other organic acids with less pollution are introduced, such as replacing perchloric acid as an additive for petrochemicals. In recent years, some companies have developed new uses for trifluoromethanesulfonic acid, such as using trifluoromethanesulfonic acid as a raw material to produce astaxanthin, which is used to feed tilapia, salmon, lobsters and high-grade shrimps. The global demand is increasing. In the field of fine chemical synthesis, trifluoromethanesulfonic acid is used to synthesize liquid crystal materials, optoelectronic materials and organic light-emitting diode (OLED) materials. These materials have important applications in display technology and optoelectronic equipment.

[0003] Electrolytic fluorination is currently a common method for preparing trifluoromethanesulfonic acid. Crude trifluoromethanesulfonic acid is prepared by acidification with trifluoromethanesulfonate, and further vacuum distillation is performed to obtain fine trifluoromethanesulfonic acid. In this process, the boiling point of trifluoromethanesulfonic acid is about 167°C, and the boiling point of sulfuric acid is about 338°C. Normally, vacuum distillation is used for separation and purification. However, due to the presence of water in the raw materials, trifluoromethanesulfonic acid combines with water to form a monohydrate during the acidification process, and forms the highest azeotrope with sulfuric acid, with a boiling point of more than 330°C. It cannot be effectively separated from sulfuric acid and can only be discharged into the three wastes for disposal. The loss of trifluoromethanesulfonic acid product is as high as 3%-5%, and there is SO4 in the distillation product. 2- High, high product cost problem.

[0004] Chinese patent CN111116424B discloses a method for preparing trifluoromethanesulfonic acid by continuous hydrolysis, comprising: 1) sending trifluoromethanesulfonyl fluoride gas and metal hydroxide solution into a falling film tubular reactor at a molar ratio of 1:1.05-1.2, and carrying out continuous neutralization and hydrolysis reaction under the conditions of pressure 0.1-0.2MPa and temperature 40-50°C; 2) pumping the reaction solution into a drying tower for drying, and then extracting by initial solvent dissolution to obtain trifluoro+methanesulfonic acid alkali metal salt; 3) acidifying the metal salt with concentrated sulfuric acid to obtain a crude trifluoromethanesulfonic acid product, and further purifying to obtain a fine trifluoromethanesulfonic acid product. In this method, both acidification and distillation purification use traditional kettle reactors, and the residual water-containing trifluoromethanesulfonic acid in the kettle at the later stage of distillation cannot be effectively recovered, and the product yield is low.

[0005] Chinese patent CN113845446B discloses a method for preparing trifluoromethanesulfonic acid, comprising: 1) adding alkali to water and stirring to form a suspension, then dripping trifluoromethyl trifluoromethanesulfonate for hydrolysis reaction, filtering the solution after the reaction to remove solid impurities and obtain a clear filtrate; 2) vacuum drying the filtrate to obtain a trifluoromethanesulfonic acid metal salt; 3) reacting the trifluoromethanesulfonic acid metal salt with concentrated sulfuric acid to obtain a crude trifluoromethanesulfonic acid product, and further reducing the pressure to distill to obtain trifluoromethanesulfonic acid. In this method, due to the low boiling point of trifluoromethyl trifluoromethanesulfonate, the exothermic gasification loss in the reaction process is large, and there is also a problem that there is no effective measure to remove the trifluoromethanesulfonic acid bound water in the kettle residue during the acidification process, and the product yield is low. Summary of the invention

[0006] In order to overcome the above problems existing in the prior art, the object of the present invention is to provide a device and method for continuously removing trifluoromethanesulfonic acid bound water, so as to reduce the loss of trifluoromethanesulfonic acid and improve the yield of preparing trifluoromethanesulfonic acid.

[0007] To achieve the purpose of the present invention, the specific technical solutions provided by the present invention are as follows:

[0008] A device for continuously removing bound water from trifluoromethanesulfonic acid, comprising a water removal unit and a distillation unit;

[0009] The dehydration unit comprises an adsorption tower and a dehydration tower, wherein an explosion-proof heating assembly is fixedly installed inside the adsorption tower, the tower is filled with molecular sieves, and the adsorption tower is connected to the lower side of the dehydration tower through a bottom outlet pipe; the dehydration tower is a packed tower, and a gas distributor is installed at the lower part of the packing;

[0010] The distillation unit comprises a distillation tower, a sulfuric acid storage tank and a trifluoromethanesulfonic acid storage tank, the top of the distillation tower is connected to a condenser through a pipeline, and the outlet of the condenser is connected to the top of the distillation tower and the trifluoromethanesulfonic acid storage tank through a pipeline; the bottom of the distillation tower is connected to a reboiler and a liquid phase extraction pipe, and the liquid phase extraction pipe is connected to the sulfuric acid storage tank;

[0011] The liquid phase outlet at the bottom of the dehydration tower is connected to the upper part of the distillation tower through a pipeline.

[0012] Preferably, a vent pipe is provided at the top of the dewatering tower, a regulating valve is installed on the vent pipe, a liquid inlet pipe is connected to the upper part of the dewatering tower, and a filter and a flow meter are installed on the liquid inlet pipe in sequence along the liquid flow direction;

[0013] The top of the adsorption tower is provided with an air inlet pipe, on which a second regulating valve is installed, and a second flow meter is installed on the connecting pipeline between the adsorption tower and the dewatering tower;

[0014] A shielded pump, a regulating valve and a flow meter are installed on the connecting pipeline between the dehydration tower and the distillation tower;

[0015] A liquid phase extraction valve is provided on the pipeline between the distillation tower and the sulfuric acid storage tank;

[0016] A gas phase extraction valve is arranged on the pipeline between the condenser and the trifluoromethanesulfonic acid storage tank.

[0017] Preferably, the liquid inlet pipe is made of rigid-lined polytetrafluoroethylene material, the filter is a stainless steel sintered filter element, and the filtration accuracy is 1.3 μm; the gas distributor is made of PTFE material, and the opening is upward.

[0018] Preferably, the dewatering tower is provided with a packing section filled with regular corrugated packing made of PTFE, and the packing is fixed by a tetrafluoro support plate; the distillation tower is provided with a packing section filled with tetrafluoro high-temperature resistant ball rings.

[0019] The present invention also provides a method for continuously removing bound water in trifluoromethanesulfonic acid, which is carried out using a device for continuously removing bound water in trifluoromethanesulfonic acid, and the steps include:

[0020] S1, pass SO3 gas into the lower part of the dehydration tower;

[0021] S2, the trifluoromethanesulfonic acid liquid containing 6%-15% of bound water is passed into the upper part of the dehydration tower, and the SO3 gas entering the lower part of the dehydration tower is reversely contacted to remove the bound water to obtain a mixed solution. The reaction equation of the dehydration process is as follows:

[0022] CF3SO3H·H2O+SO3→CF3SO3H+H2SO4

[0023] S3, the mixed liquid is extracted from the liquid phase outlet at the bottom of the dehydration tower and transported to the distillation tower. The bottom liquid of the distillation tower is electrically heated to 150-180°C by a reboiler, and the gas phase at the top of the distillation tower is condensed by a condenser and refluxed. The temperature after condensation is ≤50°C;

[0024] S4, the gas phase of the distillation tower is condensed by the condenser to form liquid trifluoromethanesulfonic acid, and the extraction amount is controlled by adjusting the gas phase extraction valve. The bottom of the trifluoromethanesulfonic acid storage tank is sampled for detection and analysis until the purity of the product trifluoromethanesulfonic acid is ≥99.5%, the water content is ≤500ppm, and the F - ≤10ppm, SO4 2- ≤45ppm, the product is obtained;

[0025] S5. The distillation tower kettle extracts the by-product sulfuric acid through the liquid phase extraction valve and enters the sulfuric acid storage tank.

[0026] Preferably, in step S1, the intake flow rate of SO3 gas is 3-5m 3 / h, in step S1, the intake flow rate of SO3 gas is 3-5m 3 / h. If the SO3 gas contains impurities, the SO3 gas is first introduced into the adsorption tower (2). After the impurities are adsorbed by the molecular sieve in the adsorption tower (2), the SO3 gas is then introduced into the lower part of the dehydration tower (1). The pressure in the adsorption tower (2) is controlled to be 0.1-0.2MPa and the temperature to be 130-150°C.

[0027] Preferably, in step S1, the adsorption tower is provided with two groups A and B, which are used alternately, and adopt an "adsorption-hot blowing regeneration-cold blowing-adsorption" cycle mode, with program-controlled adsorption for 40-50 hours and analytical regeneration for 40-50 hours.

[0028] Preferably, in step S2, the inlet flow rate of trifluoromethanesulfonic acid liquid is 3-4m 3 / h, and control the pressure in the dehydration tower to 0.01-0.02MPa.

[0029] Preferably, in step S3, the flow rate of the mixed liquid entering the distillation tower is controlled by regulating valve 3 to be 3.5-4m 3 / h, and the liquid level in the distillation tower is controlled to be 300-500mm by regulating valve three and the liquid phase extraction valve.

[0030] Preferably, the purity of the byproduct sulfuric acid is ≥95%.

[0031] The device and method for continuously removing bound water in trifluoromethanesulfonic acid of the present invention have the following beneficial effects:

[0032] 1. The present invention uses SO3 gas as a dehydrating agent, and effectively removes bound water in trifluoromethanesulfonic acid through gas-liquid reverse contact reaction. This method not only solves the problem that trifluoromethanesulfonic acid monohydrate is difficult to recycle in traditional processes, but also significantly improves the yield and purity of trifluoromethanesulfonic acid. The purity of trifluoromethanesulfonic acid in the final product can reach more than 99.5%, the moisture content is less than 500ppm, and the trifluoromethanesulfonic acid can reach 100%. - and SO4 2- The impurity content is also far below the industry standard and can be used directly without further purification.

[0033] 2. During the water removal process, the purity of the generated byproduct sulfuric acid is as high as 95% or more, which has high commercial value and maximizes the utilization of resources. At the same time, the entire process achieves zero emissions, which is in line with the concept of green chemistry and sustainable development.

[0034] 3. The device designed by the present invention includes a dehydration unit and a distillation unit, each unit is closely connected by a pipeline and a valve, and a continuous production process is formed by using a dry dehydration and distillation method to continuously purify and obtain fine trifluoromethanesulfonic acid. This design greatly improves production efficiency, reduces manual intervention, and reduces raw material unit consumption and production costs.

[0035] 4. The device integrates a variety of automatic control components, such as regulating valves, flow meters, shielded pumps, etc., making the entire production process easy to operate, monitor and maintain. At the same time, the alternating use of the two adsorption towers is controlled by the program to achieve continuous and stable operation of the equipment.

[0036] 5. The process route adopted by the present invention is stable and reliable, ensuring the stability and consistency of product quality. Since the device and method of the present invention have the advantages of high efficiency, environmental protection, and high resource utilization, they can significantly reduce production costs and improve economic benefits in practical applications. At the same time, its environmental protection characteristics also meet the requirements of modern society for green production and have significant social value. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The schematic diagram of the device for continuously removing bound water from trifluoromethanesulfonic acid of the present invention is shown;

[0038] Explanation of the markings in the figure: 1. Dewatering tower; 2. Adsorption tower; 3. Distillation tower; 4. Sulfuric acid storage tank; 5. Trifluoromethanesulfonic acid storage tank; 6. Condenser; 7. Reboiler; 8. Vent pipe; 9. Liquid inlet pipe; 10. Filter; 11. Flow meter one; 12. Gas distributor; 13. Control valve one; 14. Inlet pipe; 15. Control valve two; 16. Flow meter two; 17. Shielded pump; 18. Control valve three; 19. Flow meter three; 20. Liquid phase production valve; 21. Gas phase production valve. DETAILED DESCRIPTION

[0039] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0040] Example 1

[0041] like Figure 1 As shown, it is a schematic diagram of the structure of the device for continuously removing bound water in trifluoromethanesulfonic acid according to the present invention.

[0042] A device for continuously removing bound water from trifluoromethanesulfonic acid, comprising a water removal unit and a distillation unit;

[0043] The dewatering unit includes a dewatering tower 1, which is a packed tower, and is internally provided with regular corrugated packing made of PTFE. The packing is fixed by a polytetrafluoroethylene support plate, and a gas distributor 12 is provided at the lower part of the packing; a vent pipe 8 is provided at the top of the dewatering tower 1, and a regulating valve 13 is installed on the vent pipe 8. A pressure monitoring point is provided at the top of the dewatering tower 1, and is interlocked with the top regulating valve 13 to control the top pressure of the dewatering tower 1 to be 0.01-0.02MPa; a liquid inlet pipe 9 is connected to the upper part of the dewatering tower 1, and a valve, a filter 10 and a flowmeter 11 are installed on the liquid inlet pipe 9 in sequence. The liquid inlet pipe 9 is made of a rigid-lined polytetrafluoroethylene material, and trifluoromethanesulfonic acid containing bound water is transported by a magnetic pump. The valve controls the inlet flow rate, and the filter 10 is a stainless steel sintered filter element with a filtration accuracy of 1.3μm; a liquid phase outlet is provided at the bottom of the dewatering tower 1.

[0044] The dehydration unit also includes an adsorption tower 2, which has an explosion-proof heating component fixedly installed inside the adsorption tower 2. The heating rod in the explosion-proof heating component is made of S30408 ​​and has a heating power of 15KW. The tower is filled with molecular sieves, and the molecular sieve model is 5A with a pore size of 0.5 nanometers, which is used to adsorb small molecular impurities in SO3 gas; an air inlet pipe 14 is arranged on the top of the adsorption tower 2, and a regulating valve 15 is installed on the air inlet pipe 14; the adsorption tower 2 is connected to the lower side of the dehydration tower 1 through the bottom air outlet pipe, and is connected to the gas distributor 12 inside the dehydration tower 1. The gas distributor 12 is made of PTFE and has an opening facing upward. A flow meter 16 is installed on the connecting pipeline between the adsorption tower 2 and the dehydration tower 1.

[0045] The distillation unit comprises a distillation tower 3, a sulfuric acid storage tank 4 and a trifluoromethanesulfonic acid storage tank 5. A packing section is arranged inside the distillation tower 3 and filled with a tetrafluoro high temperature resistant ball ring. The liquid phase outlet at the bottom of the water removal tower 1 is connected to the upper part of the distillation tower 3 through a pipeline. A shielded pump 17, a regulating valve 18 and a flow meter 19 are installed on the connecting pipeline between the water removal tower 1 and the distillation tower 3. A condenser 6 is connected to the top of the distillation tower 3 through a pipeline. The outlet of the condenser 6 is connected to the top of the distillation tower 3 and the trifluoromethanesulfonic acid storage tank 5 through a pipeline. The outlet of the condenser 6 increases the gas The liquid phase extraction valve 21 adjusts the trifluoromethanesulfonic acid extraction amount of the distillation tower 3, and the vacuum negative pressure of the storage tank is used to control the tower top pressure -0.07 to -0.09MPa; the bottom of the distillation tower 3 is connected to a reboiler 7 and a sulfuric acid extraction pipe, the sulfuric acid extraction pipe is connected to a sulfuric acid storage tank 4, and a liquid phase extraction valve 20 is arranged on the pipeline; the materials of the condenser 6 and the reboiler 7 are both 316L, and the reboiler 7 is heated by an external electric heating plate with a power of 35KW. The condenser 6 is cooled by circulating water, and the temperature after the condenser 6 is controlled to be ≤50°C.

[0046] The distillation tower 3 and the dewatering tower 1 are both steel lined with PTFE, with a lining thickness of 3 mm; the vacuum connected to the upper part of the sulfuric acid storage tank 4 and the trifluoromethanesulfonic acid storage tank 5 is a water ring vacuum pump, and the air extraction capacity is 2.5m 3 / h, a transfer pipe and a sampling valve are provided at the bottom of the sulfuric acid storage tank 4 and the trifluoromethanesulfonic acid storage tank 5.

[0047] The device designed by the present invention includes a dehydration unit and a distillation unit, each unit is closely connected by a pipeline and a valve, and a continuous production process is formed by using a dry dehydration and distillation method to continuously purify and obtain fine trifluoromethanesulfonic acid. This design greatly improves production efficiency, reduces manual intervention, reduces raw material unit consumption and production costs; a variety of automatic control elements such as a regulating valve, a flow meter, a shielded pump, etc. are integrated in the device, making the entire production process easy to operate, easy to monitor and maintain. At the same time, the alternating use of two groups of adsorption towers 2 is controlled by a program, so that the continuous and stable operation of the equipment is achieved.

[0048] Example 2

[0049] A method for continuously removing bound water from trifluoromethanesulfonic acid is carried out using a device for continuously removing bound water from trifluoromethanesulfonic acid according to Example 1, wherein the bound water in trifluoromethanesulfonic acid exists in the form of monohydrate, mainly produced from the residual liquid in the late distillation process of the trifluoromethanesulfonic acid preparation process, containing about 6-15% water, a melting point of about 32°C, a boiling point of 230°C, and impurities SO4 2- Content 1-2%.

[0050] The method comprises the following steps:

[0051] S1, bottled SO3 is decompressed and then introduced into adsorption tower 2 in gas form for adsorption and impurity removal. The intake flow rate of SO3 gas is 3m 3 / h, the pressure in the adsorption tower 2 is controlled to be 0.2MPa through the air inlet regulating valve 15, and the temperature in the tower is controlled to be 140℃ by adjusting the voltage of the heating rod. The 5A adsorbent in the tower selectively adsorbs and removes a small amount of small molecule gas in the raw gas, and the SO3 gas passes through the molecular sieve in the adsorption tower 2 to adsorb impurities and then enters the lower part of the dehydration tower 1; wherein, the adsorption tower 2 is set to have two groups A and B, which are used alternately, and each group of adsorption towers 2 adopts the cycle mode of "adsorption-hot blowing regeneration-cold blowing-adsorption" for operation. When the adsorption tower 2 of group A is performing adsorption operation, the adsorption tower 2 of group B is performing hot blowing regeneration and cold blowing operation. The program is set to control the adsorption for 48h, and the analytical regeneration is operated for 48h. The analytical regeneration includes hot blowing regeneration and cold blowing operation.

[0052] S2, the trifluoromethanesulfonic acid liquid containing 10% of bound water is transported to the upper liquid inlet pipe 9 of the dehydration tower 1 through a fluorine-lined magnetic pump, and enters the dehydration tower 1 after passing through the filter 10. The inlet flow rate of the trifluoromethanesulfonic acid liquid is 3.5m 3 / h, and contacts with the SO3 gas entering from the lower part in reverse, removes bound water, and obtains a mixed liquid. The liquid level of the dehydration tower 1 is controlled by the liquid inlet valve interlocking. A pressure monitoring point is set at the top of the dehydration tower 1, and interlocking control is achieved with the regulating valve 13 on the top vent pipe 8 to control the pressure in the dehydration tower 1 to 0.015MPa. The reaction equation of the dehydration process is as follows:

[0053] CF3SO3H·H2O+SO3→CF3SO3H+H2SO4

[0054] S3, the trifluoromethanesulfonic acid and sulfuric acid mixture after dehydration is collected in the bottom of the dehydration tower 1, the mixed liquid is extracted through the liquid phase outlet at the bottom of the dehydration tower 1, and is transported to the distillation tower 3 by the shielded pump 17, and the flow rate of the mixed liquid entering the distillation tower 3 is controlled by the regulating valve 3 18 to be 3.5m 3 / h, transported to the distillation tower 3, the liquid level of the distillation tower 3 is controlled to be 300-500mm by the regulating valve 3 18 and the liquid phase extraction valve 20, the bottom liquid of the distillation tower 3 is electrically heated to 160°C by the reboiler 7, the trifluoromethanesulfonic acid is vaporized and rises along the tower, the top gas phase of the distillation tower 3 is condensed by the condenser 6 and refluxed, the temperature after condensation is 30°C, and the top pressure of the tower is controlled and adjusted to -0.09MPa by the gas phase extraction valve 21;

[0055] S4, the gas phase of the distillation tower 3 is condensed by the condenser 6 to form liquid trifluoromethanesulfonic acid, and the extraction amount is controlled by adjusting the gas phase extraction valve 21. The bottom of the trifluoromethanesulfonic acid storage tank 5 is sampled for detection and analysis, and the moisture content is ≤500ppm, F - ≤10ppm, SO4 2- ≤45ppm, the analysis results are shown in Table 1, the purity of the product trifluoromethanesulfonic acid is ≥99.5%, and the product is filled;

[0056] S5, the bottom of the distillation tower 3 controls the bottom temperature at 150°C through the liquid phase extraction valve 20, extracts the by-product sulfuric acid into the sulfuric acid storage tank 4, samples and analyzes the test. The analysis results are shown in Table 2. The purity of the by-product sulfuric acid is ≥95%.

[0057] Example 3

[0058] A method for continuously removing bound water in trifluoromethanesulfonic acid is carried out using the device for continuously removing bound water in trifluoromethanesulfonic acid in Example 1.

[0059] The method comprises the following steps:

[0060] S1, bottled SO3 is decompressed and then introduced into adsorption tower 2 in gas form for adsorption treatment. The intake flow rate of SO3 gas is 5m 3 / h, the pressure in the adsorption tower 2 is controlled to be 0.1MPa through the air inlet regulating valve 15, and the temperature in the tower is controlled to be 130℃ by adjusting the voltage of the heating rod. The 5A adsorbent in the tower selectively adsorbs and removes a small amount of small molecule gas in the raw gas, and the SO3 gas passes through the molecular sieve in the adsorption tower 2 to adsorb impurities and then passes into the lower part of the dehydration tower 1; wherein, the adsorption tower 2 is provided with two groups A and B, which are used alternately, and adopts the "adsorption-hot blowing regeneration-cold blowing-adsorption" cycle mode, with program-controlled adsorption for 48 hours and analytical regeneration operation for 48 hours.

[0061] S2, the trifluoromethanesulfonic acid liquid containing 15% of bound water is transported to the upper liquid inlet pipe 9 of the dehydration tower 1 through a fluorine-lined magnetic pump, and enters the dehydration tower 1 after passing through the filter 10. The inlet flow rate of the trifluoromethanesulfonic acid liquid is 4m 3 / h, and contacts with the SO3 gas entering from the lower part in reverse direction to remove bound water and obtain a mixed liquid. The liquid level of the dehydration tower 1 is controlled by the liquid inlet valve interlocking. A pressure monitoring point is set on the top of the dehydration tower 1, which is interlocked with the regulating valve 13 on the top vent pipe 8 to control the pressure in the dehydration tower 1 to 0.01MPa.

[0062] S3, the trifluoromethanesulfonic acid and sulfuric acid mixture after dehydration is collected in the bottom of the dehydration tower 1, the mixed liquid is extracted through the liquid phase outlet at the bottom of the dehydration tower 1, and is transported to the distillation tower 3 by the shielded pump 17, and the flow rate of the mixed liquid entering the distillation tower 3 is controlled by the regulating valve 3 18 to be 4m 3 / h, transported to the distillation tower 3, the liquid level of the distillation tower 3 is controlled to be 300-500mm by the regulating valve 3 18 and the liquid phase extraction valve 20, the bottom liquid of the distillation tower 3 is electrically heated to 180°C by the reboiler 7, so that the trifluoromethanesulfonic acid is vaporized and rises along the tower, the top gas phase of the distillation tower 3 is condensed by the condenser 6 and refluxed, the temperature after condensation is 40°C, and the top pressure of the tower is controlled and adjusted to -0.08MPa by the gas phase extraction valve 21;

[0063] S4, the gas phase of the distillation tower 3 is condensed by the condenser 6 to form liquid trifluoromethanesulfonic acid, and the extraction amount is controlled by adjusting the gas phase extraction valve 21. The bottom of the trifluoromethanesulfonic acid storage tank 5 is sampled for detection and analysis, and the moisture content is ≤500ppm, F - ≤10ppm, SO4 2- ≤45ppm, the analysis results are shown in Table 1, the purity of the product trifluoromethanesulfonic acid is ≥99.5%, and the product is filled;

[0064] S5, the bottom of the distillation tower 3 controls the bottom temperature at 150°C through the liquid phase extraction valve 20, extracts the by-product sulfuric acid into the sulfuric acid storage tank 4, samples and analyzes the test. The analysis results are shown in Table 2. The purity of the by-product sulfuric acid is ≥95%.

[0065] Example 4

[0066] A method for continuously removing bound water in trifluoromethanesulfonic acid is carried out using the device for continuously removing bound water in trifluoromethanesulfonic acid in Example 1.

[0067] The method comprises the following steps:

[0068] S1, bottled SO3 is decompressed and then introduced into adsorption tower 2 in gas form for adsorption treatment. The intake flow rate of SO3 gas is 4m 3 / h, the pressure in the adsorption tower 2 is controlled to be 0.2MPa through the air inlet regulating valve 15, and the temperature in the tower is controlled to be 150℃ by adjusting the voltage of the heating rod. The 5A adsorbent in the tower selectively adsorbs and removes a small amount of small molecule gas in the raw gas, and the SO3 gas passes through the molecular sieve in the adsorption tower 2 to adsorb impurities and then passes into the lower part of the dehydration tower 1; wherein, the adsorption tower 2 is provided with two groups A and B, which are used alternately, and adopts the "adsorption-hot blowing regeneration-cold blowing-adsorption" cycle mode, with program-controlled adsorption for 48h and analytical regeneration operation for 48h.

[0069] S2, the trifluoromethanesulfonic acid liquid containing 6% of bound water is transported to the upper liquid inlet pipe 9 of the dehydration tower 1 through a fluorine-lined magnetic pump, and enters the dehydration tower 1 after passing through the filter 10. The inlet flow rate of the trifluoromethanesulfonic acid liquid is 3m 3 / h, and contacts with the SO3 gas entering from the lower part in reverse to remove bound water to obtain a mixed liquid. The liquid level of the dehydration tower 1 is controlled by the liquid inlet valve interlocking. A pressure monitoring point is set on the top of the dehydration tower 1, which is interlocked with the regulating valve 13 on the top vent pipe 8 to control the pressure in the dehydration tower 1 to 0.02MPa.

[0070] S3, the trifluoromethanesulfonic acid and sulfuric acid mixture after dehydration is collected in the bottom of the dehydration tower 1, the mixed liquid is extracted through the liquid phase outlet at the bottom of the dehydration tower 1, and is transported to the distillation tower 3 by the shielded pump 17, and the flow rate of the mixed liquid entering the distillation tower 3 is controlled by the regulating valve 3 18 to be 3.5m 3 / h, transported to the distillation tower 3, the liquid level of the distillation tower 3 is controlled to be 300-500mm by the regulating valve 3 18 and the liquid phase extraction valve 20, the bottom liquid of the distillation tower 3 is electrically heated to 150°C by the reboiler 7, so that the trifluoromethanesulfonic acid is vaporized and rises along the tower, the top gas phase of the distillation tower 3 is condensed by the condenser 6 and refluxed, the temperature after condensation is 50°C, and the top pressure of the tower is controlled and adjusted to -0.07MPa by the gas phase extraction valve 21;

[0071] S4, the gas phase of the distillation tower 3 is condensed by the condenser 6 to form liquid trifluoromethanesulfonic acid, and the extraction amount is controlled by adjusting the gas phase extraction valve 21. The bottom of the trifluoromethanesulfonic acid storage tank 5 is sampled for detection and analysis, and the moisture content is ≤500ppm, F - ≤10ppm, SO4 2- ≤45ppm, the analysis results are shown in Table 1, the purity of the product trifluoromethanesulfonic acid is ≥99.5%, and the product is filled;

[0072] Table 1 Example 1-3 trifluoromethanesulfonic acid product analysis results

[0073]

[0074] S5, the bottom of the distillation tower 3 controls the bottom temperature at 155°C through the liquid phase extraction valve 20, extracts the by-product sulfuric acid and enters the sulfuric acid storage tank 4, samples and analyzes the test. The analysis results are shown in Table 2. The purity of the by-product sulfuric acid is ≥95%, trifluoromethanesulfonic acid ω / % ≤0.5, ash ω / % ≤0.1, and transparency / mm ≥80.

[0075] Table 2 Analysis results of by-product sulfuric acid in Examples 1-3

[0076]

[0077] The device and method of the present invention can realize continuous production to remove bound water in trifluoromethanesulfonic acid, solving the problems of high energy consumption and low yield caused by conventional distillation methods to remove bound water in trifluoromethanesulfonic acid. The process is simple to operate and has a high degree of automation. The product trifluoromethanesulfonic acid H2O≤500ppm, F - ≤10ppm, SO4 2- ≤45ppm, purity ≥99.5%, meeting industry standards, purity of by-product sulfuric acid ≥95%, zero emission in the process, with great economic and social value, and easy to promote.

[0078] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A device for continuously removing bound water from trifluoromethanesulfonic acid, characterized in that: It includes a water removal unit and a distillation unit; The dehydration unit comprises an adsorption tower (2) and a dehydration tower (1); the dehydration tower (1) is a packed tower, and a gas distributor (12) is installed below the packing; an explosion-proof heating component is fixedly installed inside the adsorption tower (2), and the tower is filled with molecular sieves; the adsorption tower (2) is connected to the lower side of the dehydration tower (1) via a bottom gas outlet pipe; The distillation unit comprises a distillation tower (3), a sulfuric acid storage tank (4) and a trifluoromethanesulfonic acid storage tank (5); the top of the distillation tower (3) is connected to a condenser (6) via a pipeline, and the outlet of the condenser (6) is connected to the top of the distillation tower (3) and the trifluoromethanesulfonic acid storage tank (5) via a pipeline; the bottom of the distillation tower (3) is connected to a reboiler (7) and a liquid phase extraction pipe, and the liquid phase extraction pipe is connected to the sulfuric acid storage tank (4); The liquid phase outlet at the bottom of the dewatering tower (1) is connected to the upper part of the distillation tower (3) through a pipeline.

2. A device for continuously removing bound water in trifluoromethanesulfonic acid according to claim 1, characterized in that: The dewatering tower (1) is provided with a vent pipe (8) at the top, and a regulating valve (13) is installed on the vent pipe (8). The upper part of the dewatering tower (1) is connected with a liquid inlet pipe (9), and a filter (10) and a flow meter (11) are installed on the liquid inlet pipe (9) in sequence along the liquid flow direction; An air inlet pipe (14) is provided at the top of the adsorption tower (2), a regulating valve (15) is installed on the air inlet pipe (14), and a flow meter (16) is installed on the connecting pipeline between the adsorption tower (2) and the dewatering tower (1); A shielded pump (17), a regulating valve (18) and a flow meter (19) are installed on the connecting pipeline between the dehydration tower (1) and the distillation tower (3); A liquid phase extraction valve (20) is provided on the pipeline between the distillation tower (3) and the sulfuric acid storage tank (4); A gas phase extraction valve (21) is provided on the pipeline between the condenser (6) and the trifluoromethanesulfonic acid storage tank (5).

3. A device for continuously removing bound water in trifluoromethanesulfonic acid according to claim 2, characterized in that: The liquid inlet pipe (9) is made of a rigid-lined polytetrafluoroethylene material, and the filter (10) is a stainless steel sintered filter element with a filtration accuracy of 1.3 μm; the gas distributor (12) is made of a PTFE material with an opening facing upward.

4. A device for continuously removing bound water in trifluoromethanesulfonic acid according to claim 1, characterized in that: The dewatering tower (1) is provided with a packing section filled with regular corrugated packing made of PTFE, and the packing is fixed by a tetrafluoro support plate; the distillation tower (3) is provided with a packing section filled with tetrafluoro high-temperature resistant ball rings.

5. A method for continuously removing bound water from trifluoromethanesulfonic acid, characterized in that: The method is carried out using a device for continuously removing bound water in trifluoromethanesulfonic acid as described in any one of claims 1 to 4, and the steps include: S1, passing SO3 gas into the lower part of the dehydration tower (1); S2, the trifluoromethanesulfonic acid liquid containing 6%-15% of bound water is passed into the upper part of the dehydration tower (1), and is in reverse contact with the SO3 gas entering from the lower part of the dehydration tower (1), and the bound water is removed to obtain a mixed solution. The reaction equation of the dehydration process is as follows: CF3SO3H·H2O+SO3→CF3SO3H+H2SO4 S3, the mixed liquid is extracted from the liquid phase outlet at the bottom of the dewatering tower (1) and transported to the distillation tower (3), the bottom liquid of the distillation tower (3) is electrically heated to 150-180° C. by a reboiler (7), and the gas phase at the top of the distillation tower (3) is condensed by a condenser (6) and then refluxed, and the temperature after condensation is ≤50° C.; S4, the gas phase of the rectification tower (3) is condensed by the condenser (6) to form liquid trifluoromethanesulfonic acid, and the extraction amount is controlled by adjusting the gas phase extraction valve (21), and the bottom of the trifluoromethanesulfonic acid storage tank (5) is sampled for detection and analysis until the purity of the product trifluoromethanesulfonic acid is ≥99.5%, the water content is ≤500ppm, and the trifluoromethanesulfonic acid content is ≤99.5%. - ≤10ppm, SO4 2- ≤45ppm, the product is obtained; S5. The bottom of the distillation tower (3) extracts the by-product sulfuric acid through the liquid phase extraction valve (20) and enters the sulfuric acid storage tank (4).

6. A method for continuously removing bound water in trifluoromethanesulfonic acid according to claim 5, characterized in that: In step S1, the intake flow rate of SO3 gas is 3-5m 3 / h. If the SO3 gas contains impurities, the SO3 gas is first introduced into the adsorption tower (2). After the impurities are adsorbed by the molecular sieve in the adsorption tower (2), the SO3 gas is then introduced into the lower part of the dehydration tower (1). The pressure in the adsorption tower (2) is controlled to be 0.1-0.2MPa and the temperature to be 130-150°C.

7. A method for continuously removing bound water in trifluoromethanesulfonic acid according to claim 6, characterized in that: In step S1, the adsorption tower (2) is provided with two groups A and B, which are used alternately, and adopts the "adsorption-hot blowing regeneration-cold blowing-adsorption" cycle mode, and the program controls the adsorption for 40-50 hours and the desorption regeneration for 40-50 hours.

8. A method for continuously removing bound water in trifluoromethanesulfonic acid according to claim 5, characterized in that: In step S2, the inlet flow rate of trifluoromethanesulfonic acid liquid is 3-4m 3 / h, and the pressure in the dewatering tower (1) is controlled to be 0.01-0.02MPa.

9. A method for continuously removing bound water in trifluoromethanesulfonic acid according to claim 5, characterized in that: In step S3, the flow rate of the mixed liquid entering the distillation tower (3) is controlled to be 3.5-4m 3 / h, and the liquid level of the distillation tower (3) is controlled to be 300-500mm through the regulating valve three (18) and the liquid phase extraction valve (20).

10. The method for continuously removing bound water in trifluoromethanesulfonic acid according to claim 5, characterized in that: The purity of the by-product sulfuric acid is ≥95%.

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