Method and device for preparing electronic-grade trifluoroiodomethane through photocatalytic halogenation

Abstract

The invention discloses a method and a device for preparing electronic-grade trifluoroiodomethane through photocatalytic halogenation. The method comprises the following steps: continuously reacting trifluoromethane and iodine serving as raw materials in a reactor through ultraviolet light illumination to generate trifluoroiodomethane and hydrogen iodide; by optimizing conditions such as reaction temperature, feeding rate and ultraviolet light illumination in the reaction process, the reaction conversion rate of trifluoromethane reaches 80% or above. Efficient iodine recovery is achieved through a low-temperature condensation mode of reaction products, a continuous rectification mode is adopted, trifluoromethane with the purity larger than or equal to 99.5% is obtained at the top of a recovery tower and recycled, a hydrogen iodide byproduct with the purity larger than or equal to 99.5% is obtained at the top of a light component removal tower, and a trifluoroiodomethane product with the purity larger than or equal to 99.999% is obtained at the top of a heavy component removal tower. Compared with the traditional process, the problems of short service life of the catalyst, low reaction conversion rate and low product purity in the reaction process are solved. The method is simple in process and easy to control, and stable industrial production of trifluoroiodomethane can be realized.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method and device for preparing halogenated hydrocarbon gas through photocatalytic halogenation, in particular to a method and device for preparing electronic-grade trifluoroiodomethane through photocatalytic halogenation. BACKGROUND

[0002] Due to the excellent environmental protection properties of trifluoroiodomethane, such as an ozone depletion potential (ODP) lower than 0.0001, a global warming potential (GWP) of 1, and an atmospheric lifetime less than 1.2 days, and good fire extinguishing performance and insulation performance, trifluoroiodomethane is mainly used as a refrigerant, a fire extinguishing agent and an insulation gas.

[0003] With the vigorous development of the semiconductor industry, trifluoroiodomethane has great potential as an etching gas in the semiconductor industry. Trifluoroiodomethane can be used in 3D NAND Flash advanced processes. Compared with the same etching gas, carbon tetrafluoride and hexafluorobutadiene, trifluoroiodomethane has the advantages of high selectivity and high aspect ratio. However, the purity of the trifluoroiodomethane product generated at present in China is low,

[0004] Patent CN 113423681 proposes a one-step method for preparing trifluoroiodomethane by feeding trifluoroacetyl halide, hydrogen and iodine into a reactor in the presence of a catalyst. The method selects a transition metal catalyst, and trifluoroacetyl halide, hydrogen and iodine are reacted in the vapor phase at a temperature of about 200 DEG C to about 600 DEG C to produce a product containing trifluoroiodomethane, unreacted trifluoroacetyl halide, unreacted hydrogen, unreacted iodine, hydrogen halide and hydrogen iodide. The method has a high reaction temperature, the raw material trifluoroacetyl halide has high toxicity, and strict requirements are placed on the selection and processing of the equipment. In addition, the reaction product components are complex, and the subsequent product purification is difficult.

[0005] It is reported in the literature that the pyrolysis of trifluoroacetate and iodine to prepare trifluoroiodomethane has a relatively considerable reaction yield, but the reaction process is violent, it is difficult to continuously and stably feed iodine, the pipe blockage problem caused by iodine volatilization is serious, the utilization rate of iodine is low, and the recovery of waste iodine salt has not been effectively solved, which is not suitable for industrial production. The gas-phase catalytic reaction of fluorinated alkanes as starting materials is the main research direction of trifluoroiodine preparation at home and abroad. In the reaction process, an alkali metal catalyst with activated carbon as the carrier is used, and the reaction mechanism is mainly that CF2 carbene intermediates are formed on the surface of the catalyst, then CF3 free radicals are disproportionated, and then CF3I is generated by reacting with I2. Compared with the pyrolysis of trifluoroacetate, the method has the advantages of low raw material cost, high iodine utilization rate and continuous operation, but the problems of low catalyst activity and short service life limit its industrial production. SUMMARY

[0006] According to the problems of the prior art, the application provides a method and device for preparing electronic-grade trifluoroiodomethane through photocatalytic halogenation.

[0007]

[0008] The application optimizes the reaction temperature, feeding rate and ultraviolet light illumination conditions in the reaction process, so that the conversion rate of trifluoromethane in the reaction process reaches more than 80%, the reaction product is recycled through low-temperature condensation, the purity of trifluoromethane obtained at the top of a recovery column is greater than or equal to 99.5% through continuous rectification, the trifluoromethane is recycled, the purity of hydrogen iodide byproduct obtained at the top of a light-removing column is greater than or equal to 99.5%, and the purity of trifluoroiodomethane product obtained at the top of a heavy-removing column is greater than or equal to 99.999%. Compared with the traditional process, the problems of short service life of a catalyst, low reaction conversion rate and low product purity in the reaction process are solved. The method has a simple process and is easy to control, and can realize stable industrialized production of trifluoroiodomethane.

[0009] The application realizes the technical scheme as follows:

[0010] A method for preparing electronic-grade trifluoroiodomethane through photocatalytic halogenation comprises the following steps:

[0011] (1) raw material trifluoromethane carries raw material iodine into a reactor, and the feeding mass ratio of the raw material trifluoromethane to the raw material iodine is 1:(3-4), and the feeding temperature is 130-180 DEG C;

[0012] (2) the reaction temperature of the raw material trifluoromethane and the raw material iodine is 150-200 DEG C, the reaction pressure is 0.02-0.1 MPa, and the wavelength of the ultraviolet light illumination is 230-350 nm;

[0013] (3) the reaction product is recycled through low-temperature condensation, the condensation temperature is 10-20 DEG C, and the condensation pressure is 0.02-0.1 MPa;

[0014] (4) after the iodine is recycled, the material is rectified continuously, the purity of trifluoromethane obtained at the top of a recovery column is greater than or equal to 99.5%, the trifluoromethane is recycled, the purity of hydrogen iodide byproduct obtained at the top of a light-removing column is greater than or equal to 99.5%, and the purity of trifluoroiodomethane product obtained at the top of a heavy-removing column is greater than or equal to 99.999%.

[0015] In the step (1), the iodine feeding rate is controlled by adjusting the valve between the feeding line and the discharging line in the iodine storage tank, and the feeding mass ratio of trifluoromethane to iodine is 1:(3-4).

[0016] The step (4) is that the number of theoretical plates of the recovery tower is 30 to 60, the feeding plate position is 10 to 20, the operating pressure is 0.3MPa to 0.8MPa, the operating temperature is -55℃ to -35℃, and the reflux ratio is 20 to 50.

[0017] The step (4) is that the number of theoretical plates of the light-removing tower is 40 to 80, the feeding plate position is 20 to 40, the operating pressure is 0.2MPa to 0.7MPa, the operating temperature is -10℃ to 25℃, and the reflux ratio is 3 to 10.

[0018] The step (4) is that the number of theoretical plates of the heavy-removing tower is 20 to 40, the feeding plate position is 10 to 15, the operating pressure is 0.1MPa to 0.6MPa, the operating temperature is -5℃ to 35℃, and the reflux ratio is 2 to 5.

[0019] The device for preparing electronic-grade trifluoroiodomethane by photocatalytic halogenation of the application comprises an iodine storage tank (V101), a reactor (R101), an ultraviolet lamp (X101), an iodine recovery tank (V102), a buffer tank (V103), a compressor (C101), a recovery tower (T101), a light-removing tower (T102) and a heavy-removing tower (T103). The top of the iodine storage tank (V101) is provided with an inner extension feeding port and a discharging port, an adjusting valve is arranged between the inner extension feeding pipeline and the discharging pipeline, and the discharging pipeline is connected to the feeding port of the reactor (R101). The lower part of the reactor (R101) is provided with a feeding port, the upper part is provided with a discharging port, the discharging pipeline is connected to the iodine recovery tank (V102), the top is provided with a quartz window, the upper part of the quartz window is provided with the ultraviolet lamp (X101), the ultraviolet lamp (X101) emits ultraviolet light with a wavelength of 230nm to 350nm. The outside of the iodine recovery tank (V102) is provided with a cooling jacket, the middle part is provided with a feeding port, the bottom is provided with a discharge port, the top is provided with a discharging port, and the discharging pipeline is connected to the buffer tank (V103). The middle part of the buffer tank (V103) is provided with a feeding port, the top is provided with a discharging port, and the discharging pipeline is connected to the compressor (C101). The compressor (C101) is provided with a feeding port and a discharging port, and the discharging pipeline is connected to the feeding port of the recovery tower (T101). The middle part of the recovery tower (T101) is provided with a feeding port, the top is provided with a tower top tapping outlet, trifluoromethane is tapped, the tower top tapping pipeline is connected to the feeding pipeline of the iodine storage tank (V101), the tower kettle is provided with a side line tapping outlet, and the tower kettle side line tapping pipeline is connected to the feeding port of the light-removing tower (T102). The middle part of the light-removing tower (T102) is provided with a feeding port, the top is provided with a tower top tapping outlet, hydrogen iodide is tapped, the tower kettle is provided with a side line tapping outlet, and the tower kettle side line tapping pipeline is connected to the heavy-removing tower (T103). The middle part of the heavy-removing tower (T103) is provided with a feeding port, the top is provided with a tower top tapping outlet, and trifluoroiodomethane is tapped.

[0020] The specific description is as follows:

[0021] (1) raw material trifluoromethane is passed into the iodine storage tank according to the set flow, carries the iodine into the reactor, the addition amount of iodine is controlled by adjusting the valve between the inlet pipeline and the outlet pipeline in the iodine storage tank, the mass ratio of trifluoromethane and iodine is 1: (3-4), the feeding temperature of the iodine storage tank is 130-180℃;

[0022] (2) trifluoromethane and iodine are reacted in the reactor, the reaction temperature is 150-200℃, the reaction pressure is 0.02-0.1 MPa, and the wavelength of ultraviolet light is 230-350 nm;

[0023] (3) the reaction product enters the iodine recovery tank, and the iodine in the reaction product is recovered by low-temperature condensation, the condensation temperature is 10-20℃, and the condensation pressure is 0.02-0.1 MPa;

[0024] (4) after the iodine is recovered, the material is pressurized by a compressor and enters the refining system, a continuous distillation method is used, the purity of trifluoromethane obtained at the top of the recovery column is ≥99.5%, the purity of hydrogen iodide byproduct obtained at the top of the light removal column is ≥99.5%, and the purity of trifluoroiodomethane product obtained at the top of the heavy removal column is ≥99.999%.

[0025] The number of theoretical plates of the recovery column is 30-60, the feeding plate position is 10-20, the operating pressure is 0.3-0.8 MPa, the operating temperature is -55- -35℃, and the reflux ratio is 20-50.

[0026] The number of theoretical plates of the light removal column is 40-80, the feeding plate position is 20-40, the operating pressure is 0.2-0.7 MPa, the operating temperature is -10-25℃, and the reflux ratio is 3-10.

[0027] The number of theoretical plates of the heavy removal column is 20-40, the feeding plate position is 10-15, the operating pressure is 0.1-0.6 MPa, the operating temperature is -5-35℃, and the reflux ratio is 2-5.

[0028] The beneficial results of the present application are:

[0029] 1. Trifluoromethane and iodine are used for reaction, the raw materials are easy to obtain and the cost is low.

[0030] 2. The reaction temperature in the reaction process is mild, and the reaction can be promoted by light, and the requirement for equipment material is low.

[0031] 3. The conversion rate of trifluoromethane in the reaction process reaches more than 80%, the raw materials in the reaction product are efficiently recovered, the byproduct hydrogen iodide can be sold as a product, and the production cost is greatly reduced.

[0032] 4. The reaction product is refined by continuous rectification process, the purity of hydrogen iodide by-product is ≥99.5% at the top of the light removal column, the purity of trifluoroiodomethane product is ≥99.999% at the top of the heavy removal column, the energy consumption is small during the refining process, the yield is high, the process is simple, easy to control, and stable industrial production of trifluoroiodomethane can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 A method for preparing electronic grade trifluoroiodomethane by photocatalytic halogenation and a device schematic diagram:

[0034] V101: iodine storage tank; R101: reactor; X101: ultraviolet lamp; V102: iodine recovery tank; V103: buffer tank; C101:

[0035] Compressor; T101: recovery column; T102: light removal column; T103: heavy removal column DETAILED DESCRIPTION

[0036] The application discloses a method and device for preparing electronic grade trifluoroiodomethane by photocatalytic halogenation: raw material trifluoromethane and iodine are continuously reacted to generate trifluoroiodomethane and hydrogen iodide in a reactor through ultraviolet light irradiation. By optimizing the reaction temperature, feeding rate and ultraviolet light irradiation conditions in the reaction process, the reaction conversion rate of trifluoromethane reaches more than 80%. The reaction product is subjected to low-temperature condensation to realize efficient recovery of iodine, a continuous rectification mode is adopted, the purity of trifluoromethane is ≥99.5% at the top of the recovery column, the purity of hydrogen iodide by-product is ≥99.5% at the top of the light removal column, and the purity of trifluoroiodomethane product is ≥99.999% at the top of the heavy removal column. Compared with the traditional process, the problems of short service life of the catalyst, low reaction conversion rate and low product purity in the reaction process are solved. The method has a simple process, is easy to control, and can realize stable industrial production of trifluoroiodomethane.

[0037] As Figure 1As shown, a device for preparing electronic-grade trifluoroiodomethane by photocatalytic halogenation includes: an iodine storage tank (V101), a reactor (R101), a UV lamp (X101), an iodine recovery tank (V102), a buffer tank (V103), a compressor (C101), a recovery column (T101), a light tower (T102), and a heavy tower (T103). The iodine storage tank (V101) is provided with an inner extension feed inlet and a discharge outlet at the top, an adjusting valve is arranged between the inner extension feed pipeline and the discharge pipeline, and the discharge pipeline is connected to the feed inlet of the reactor (R101); the reactor (R101) is provided with a feed inlet at the lower part and a discharge outlet at the upper part, the discharge pipeline is connected to the iodine recovery tank (V102), a quartz window is arranged at the top, a UV lamp (X101) is arranged at the upper part of the quartz window, the UV lamp (X101) is irradiated with ultraviolet light with a wavelength of 230nm-350nm; the iodine recovery tank (V102) is provided with a cooling jacket outside, a feed inlet in the middle, a discharge outlet at the top, and a discharge port at the bottom, and the discharge pipeline is connected to the buffer tank (V103); the buffer tank (V103) is provided with a feed inlet in the middle and a discharge outlet at the top, and the discharge pipeline is connected to the compressor (C101); the compressor (C101) is provided with a feed inlet and a discharge outlet, and the discharge pipeline is connected to the feed inlet of the recovery column (T101); the recovery column (T101) is provided with a feed inlet in the middle, a tower top outlet at the top, and a tower bottom outlet at the bottom, and the tower top outlet is connected to the feed pipeline of the iodine storage tank (V101); the tower bottom outlet is connected to the feed inlet of the light tower (T102); the light tower (T102) is provided with a feed inlet in the middle, a tower top outlet at the top, and a tower bottom outlet at the bottom, and the tower top outlet is connected to the feed inlet of the light tower (T102); the tower bottom outlet is connected to the feed inlet of the heavy tower (T103); and the heavy tower (T103) is provided with a feed inlet in the middle, a tower top outlet at the top, and a tower bottom outlet at the bottom, and the tower top outlet is connected to the feed inlet of the heavy tower (T103).

[0038] The specific implementation is as follows:

[0039] (1) The raw material trifluoromethane is fed into the iodine storage tank at a set flow rate, and the iodine is carried into the reactor, the amount of iodine added is controlled by adjusting the adjusting valve between the inner extension feed pipeline and the discharge pipeline of the iodine storage tank, the mass ratio of trifluoromethane and iodine is 1:(3-4), and the feeding temperature of the iodine storage tank is 130℃-180℃;

[0040] (2) Trifluoromethane and iodine are reacted in the reactor, the reaction temperature is 150℃-200℃, the reaction pressure is 0.02MPa-0.1MPa, and the wavelength of the irradiated ultraviolet light is 230nm-350nm;

[0041] (3) The reaction product enters the iodine recovery tank, and the iodine in the reaction product is recovered by low-temperature condensation, the condensation temperature is 10℃-20℃, and the condensation pressure is 0.02MPa-0.1MPa;

[0042] (4) The material after iodine recovery is pressurized by a compressor and then enters a refining system. By using continuous rectification, the purity of trifluoromethane obtained at the top of the recovery tower is ≥99.5%, the purity of hydrogen iodide obtained at the top of the light-removing tower is ≥99.5%, and the purity of trifluoroiodomethane obtained at the top of the heavy-removing tower is ≥99.999%.

[0043] The number of theoretical plates of the recovery tower is 30 to 60, the feeding plate position is 10 to 20, the operating pressure is 0.3 MPa to 0.8 MPa, the operating temperature is -55°C to -35°C, and the reflux ratio is 20 to 50.

[0044] The number of theoretical plates of the light-removing tower is 40 to 80, the feeding plate position is 20 to 40, the operating pressure is 0.2 MPa to 0.7 MPa, the operating temperature is -10°C to 25°C, and the reflux ratio is 3 to 10.

[0045] The number of theoretical plates of the heavy-removing tower is 20 to 40, the feeding plate position is 10 to 15, the operating pressure is 0.1 MPa to 0.6 MPa, the operating temperature is -5°C to 35°C, and the reflux ratio is 2 to 5.

[0046] Example 1

[0047] The application is further described below in combination with the accompanying Figure 1 and specific embodiments.

[0048] (1) The temperature of the iodine storage tank is controlled at 150°C. The raw material trifluoromethane is fed into the iodine storage tank at a flow rate of 1 kg / h. The iodine feeding flow rate is controlled at 3.5 kg / h by adjusting the valve between the feeding line and the discharging line in the iodine storage tank.

[0049] (2) The trifluoromethane and iodine are reacted in the reactor. The reaction temperature is controlled at 170°C, the reaction pressure is 0.05 MPa, and the wavelength of the ultraviolet light is 230 nm to 350 nm.

[0050] (3) The reaction product is collected from the discharging port of the reactor and then enters the iodine recovery tank. The iodine in the reaction product is recovered by low-temperature condensation. The condensation temperature is 10°C, and the condensation pressure is 0.05 MPa.

[0051] (4) The material after iodine recovery is pressurized to 0.9 MPa by a compressor and then enters the recovery tower. The operating pressure of the recovery tower is 0.8 MPa, and the operating temperature is -35°C. Trifluoromethane is collected from the top of the recovery tower and then enters the feeding line of the iodine storage tank. The material after recovery is collected from the side line of the recovery tower and then enters the light-removing tower.

[0052] (5) The operating pressure of the light-removing tower is 0.7 MPa, and the operating temperature is 25°C. Hydrogen iodide is collected from the top of the light-removing tower. The material after light removal is collected from the side line of the light-removing tower and then enters the heavy-removing tower.

[0053] (6) The operating pressure of the heavy component removal column is 0.6 MPa, and the operating temperature is 35℃. The trifluoroiodomethane is collected from the top of the heavy component removal column;

[0054] (7) The purity of the trifluoroiodomethane product is 99.9993%, the purity of the hydrogen iodide byproduct is 99.8%, and the purity of the recovered trifluoromethane is 99.6%.

[0055] Example 2

[0056] (1) The temperature of the iodine storage tank is controlled at 140℃. The raw material trifluoromethane is fed into the iodine storage tank at a flow rate of 1 kg / h. The iodine feed flow rate is controlled at 3.3 kg / h by adjusting the valve between the inlet line and the outlet line in the iodine storage tank;

[0057] (2) The trifluoromethane and iodine are reacted in the reactor. The reaction temperature is controlled at 160℃, and the reaction pressure is 0.06 MPa. The ultraviolet light wavelength is 230 nm-350 nm;

[0058] (3) The reaction product is collected from the outlet of the reactor and then enters the iodine recovery tank. The iodine in the reaction product is recovered by low-temperature condensation. The condensation temperature is 10℃, and the condensation pressure is 0.06 MPa;

[0059] (4) After the iodine is recovered, the material is pressurized to 0.7 MPa by a compressor and then enters the recovery column. The operating pressure of the recovery column is 0.6 MPa, and the operating temperature is -40℃. The trifluoromethane is collected from the top of the recovery column and enters the inlet line of the iodine storage tank. The recovered material is collected from the side line of the recovery column and enters the light component removal column;

[0060] (5) The operating pressure of the light component removal column is 0.5 MPa, and the operating temperature is 15℃. The hydrogen iodide is collected from the top of the light component removal column. The light component removal column is connected to the side line of the recovery column;

[0061] (6) The operating pressure of the heavy component removal column is 0.4 MPa, and the operating temperature is 25℃. The trifluoroiodomethane is collected from the top of the heavy component removal column;

[0062] (7) The purity of the trifluoroiodomethane product is 99.9994%, the purity of the hydrogen iodide byproduct is 99.6%, and the purity of the recovered trifluoromethane is 99.6%.

[0063] Example 3

[0064] (1) The temperature of the iodine storage tank is controlled at 150℃. The raw material trifluoromethane is fed into the iodine storage tank at a flow rate of 1 kg / h. The iodine feed flow rate is controlled at 3.7 kg / h by adjusting the valve between the inlet line and the outlet line in the iodine storage tank;

[0065] (2) The trifluoromethane and iodine are reacted in the reactor. The reaction temperature is controlled at 160℃, and the reaction pressure is 0.05 MPa. The ultraviolet light wavelength is 230 nm-350 nm;

[0066] (3) The reaction product is taken out from the reactor outlet and enters the iodine recovery tank, and iodine in the reaction product is recovered by low-temperature condensation, the condensation temperature is 10℃, and the condensation pressure is 0.05 MPa;

[0067] (4) After the iodine is recovered, the material is pressurized to 0.5 MPa by a compressor and then enters the recovery column, the operating pressure of the recovery column is 0.4 MPa, the operating temperature is-48℃, trifluoromethane is taken out from the top of the recovery column and enters the iodine storage tank feed line, and the recovered material is taken out from the side line of the recovery column and enters the light-removing column;

[0068] (5) The operating pressure of the light-removing column is 0.3 MPa, the operating temperature is 2℃, hydrogen iodide is taken out from the top of the light-removing column, and the light-removed material is taken out from the side line of the light-removing column and enters the heavy-removing column;

[0069] (6) The operating pressure of the heavy-removing column is 0.2 MPa, the operating temperature is 8℃, and trifluoroiodomethane is taken out from the top of the heavy-removing column;

[0070] (7) The purity of trifluoroiodomethane product is 99.9995%, the purity of hydrogen iodide byproduct is 99.7%, and the purity of recovered trifluoromethane is 99.6%.

[0071] The technical scheme disclosed and presented in the present application can be realized by referring to the content of the present application, appropriately changing the conditions and routes, etc. Although the method and preparation technology of the present application have been described by means of preferred embodiments, it is obvious for those skilled in the art that the method and technical route of the present application can be modified or recombined without departing from the content, spirit and scope of the present application, to realize the final preparation technology. It is particularly pointed out that all similar substitutions and modifications are obvious to those skilled in the art, and they are considered to be included in the spirit, scope and content of the present application.

[0072] The above-mentioned embodiments are only preferred embodiments of the present application, and cannot be used to limit the protection scope of the present application, and any non-essential changes and substitutions made by those skilled in the art on the basis of the present application are within the scope of the present application.

Claims

1. A method for the photocatalytic halogenation for the production of electronic grade trifluoroiodomethane, characterized in that It comprises the following contents: (1) The raw material trifluoromethane carries the raw material iodine into the reactor, and the raw material trifluoromethane and the raw material iodine are fed at a mass ratio of 1:(3-4), and the feeding temperature is 130-180℃; (2) The raw material trifluoromethane and the raw material iodine are reacted at a temperature of 150-200℃, a reaction pressure of 0.02-0.1 MPa, and a wavelength of 230-350 nm of the ultraviolet light; (3) The reaction product is recovered by low-temperature condensation to recover the raw material iodine, and the condensation temperature is 10-20℃ and the condensation pressure is 0.02-0.1 MPa; (4) After the iodine is recovered, the material is subjected to continuous rectification, and at the top of the recovery tower, trifluoromethane with a purity of ≥99.5% is obtained, which is recycled, at the top of the light-removing tower, hydrogen iodide with a purity of ≥99.5% is obtained as a byproduct, and at the top of the heavy-removing tower, trifluoroiodomethane with a purity of ≥99.999% is obtained.

2. The device for photocatalytic halogenation preparation of electronic grade trifluoroiodomethane according to claim 1, characterized in that: The device for preparing electronic-grade trifluoroiodomethane by photocatalytic halogenation comprises an iodine storage tank (V101), a reactor (R101), an ultraviolet lamp (X101), an iodine recovery tank (V102), a buffer tank (V103), a compressor (C101), a recovery tower (T101), a light-removing tower (T102), and a heavy-removing tower (T103). The top of the iodine storage tank (V101) is provided with an inner extension feeding port and a discharging port, an adjusting valve is arranged between the inner extension feeding pipeline and the discharging pipeline, and the discharging pipeline is connected to the feeding port of the reactor (R101). The lower part of the reactor (R101) is provided with a feeding port, the upper part is provided with a discharging port, the discharging pipeline is connected to the iodine recovery tank (V102), the top is provided with a quartz window, the upper part of the quartz window is provided with the ultraviolet lamp (X101), the wavelength of the ultraviolet light of the ultraviolet lamp (X101) is 230-350 nm, the outside of the iodine recovery tank (V102) is provided with a cooling jacket, the middle part is provided with a feeding port, the bottom is provided with a discharge port, the top is provided with a discharging port, and the discharging pipeline is connected to the buffer tank (V103). The middle part of the buffer tank (V103) is provided with a feeding port, the top is provided with a discharging port, and the discharging pipeline is connected to the compressor (C101). The compressor (C101) is provided with a feeding port and a discharging port, and the discharging pipeline is connected to the feeding port of the recovery tower (T101). The middle part of the recovery tower (T101) is provided with a feeding port, the top is provided with a tower top tapping outlet, trifluoromethane is tapped, the tower top tapping pipeline is connected to the feeding pipeline of the iodine storage tank (V101), the tower kettle is provided with a side line tapping outlet, and the tower kettle side line tapping pipeline is connected to the feeding port of the light-removing tower (T102). The middle part of the light-removing tower (T102) is provided with a feeding port, the top is provided with a tower top tapping outlet, hydrogen iodide is tapped, the tower kettle is provided with a side line tapping outlet, and the tower kettle side line tapping pipeline is connected to the heavy-removing tower (T103). The middle part of the heavy-removing tower (T103) is provided with a feeding port, the top is provided with a tower top tapping outlet, and trifluoroiodomethane is tapped.

3. The method of claim 1, wherein: The iodine feeding rate is controlled by adjusting the adjusting valve between the inner extension feeding pipeline and the discharging pipeline of the iodine storage tank (V101), and the mass ratio of trifluoromethane to iodine is 1:(3-4).

4. The method of claim 1, wherein: The recovery tower (T101) has 30 to 60 theoretical tray plates, 10 to 20 feeding tray plate positions, an operating pressure of 0.3 to 0.8 MPa, an operating temperature of -55 to -35 DEG C, and a reflux ratio of 20 to 50.

5. The method of claim 1, wherein: The light-removing tower (T102) has 40 to 80 theoretical tray plates, 20 to 40 feeding tray plate positions, an operating pressure of 0.2 to 0.7 MPa, an operating temperature of -10 to 25 DEG C, and a reflux ratio of 3 to 10.

6. The method of claim 1, wherein: The heavy-removing tower (T103) has 20 to 40 theoretical tray plates, 10 to 15 feeding tray plate positions, an operating pressure of 0.1 to 0.6 MPa, an operating temperature of -5 to 35 DEG C, and a reflux ratio of 2 to 5.

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