Arsenic pentafluoride preparation device and preparation method

Abstract

The invention relates to an arsenic pentafluoride preparation device and method. The preparation device comprises a fluorine gas collecting tank, a first reactor, a second reactor, a rectifying tower, a heat exchanger, an arsenic trifluoride collecting steel cylinder, a product collecting steel cylinder, a first-stage adsorption tower and a second-stage adsorption tower. A fluorine gas collecting tank is connected with a first reactor and a second reactor, an outlet of the first reactor is connected with the second reactor, an outlet of the second reactor is connected with a rectifying tower, and a first outlet and a second outlet of the rectifying tower are connected with an arsenic trifluoride collecting steel cylinder and a heat exchanger respectively. A first outlet of the heat exchanger is connected with a second inlet of the rectifying tower and a first inlet of the product collecting steel cylinder, a second outlet of the heat exchanger is connected with a second inlet of the product collecting steel cylinder, the product collecting steel cylinder is connected with the first-stage adsorption tower, and the first-stage adsorption tower is further connected with the second-stage adsorption tower. The device is simple, the two-stage reactor is adopted to inhibit generation of byproducts, high-temperature and high-pressure conditions are not needed, the fluorine gas utilization rate and the arsenic conversion rate are increased, and high-purity arsenic pentafluoride can be prepared.

Description

Technical Field

[0001] The present invention relates to the technical field of fluoride preparation, and in particular to an arsenic pentafluoride preparation device and a preparation method. Background Art

[0002] Arsenic pentafluoride is an inorganic compound formed by arsenic and fluorine. Arsenic pentafluoride is mainly used in semiconductor manufacturing to improve semiconductor electrical properties, enhance device performance, and synthesize hexafluoroarsenate. Arsenic pentafluoride and graphite can form a conductive material with high conductivity, which is used to prepare high-performance electrode materials.

[0003] There are several methods for preparing arsenic pentafluoride: First: Arsenic reacts with fluorine gas, the equation is As+2.5F2=AsF5. The current technology has a low yield and low arsenic conversion rate. It is easy to obtain arsenic trifluoride intermediates. The reaction conditions require high temperature and high pressure, which causes great damage to the equipment. There is no report on the relevant synthesis process and synthesis equipment in the existing data, and there is no report on industrial production.

[0004] Second: Arsenic trioxide reacts with fluorine gas, the equation is As2O3+5F2=2AsF5+1.5O2. This method requires the use of highly toxic arsenic trioxide, has extremely high requirements for process conditions, requires high temperature conditions, and has high requirements for equipment, which is not suitable for industrial production.

[0005] Third: Arsenic trifluoride reacts with fluorine gas, the equation is AsF3+F2=AsF5. The raw material arsenic trifluoride of this method is not easy to obtain and needs to be prepared separately. It is expensive and the cost remains high.

[0006] Fourth: Arsenic trichloride reacts with hydrogen fluoride and chlorine, the equation is AsCl3+5HF+Cl2=AsF5+ 5HCl, this method requires the use of highly toxic arsenic trichloride, which has active chemical properties and is extremely easy to decompose. It also uses hydrogen fluoride and chlorine. The raw materials are not easy to prepare conventionally and the reaction conditions are harsh.

[0007] Fifth: Arsenic trifluoride reacts with antimony pentafluoride, the equation is AsF3+2SbF5=AsF5+SbF3·SbF5. This method also has problems such as high raw material production costs and is not suitable for industrial production.

[0008] Currently, the preparation of arsenic pentafluoride has only been introduced in relevant papers, but there is no detailed preparation process and no reports of large-scale production. Summary of the Invention

[0009] Aiming at the gaps in existing arsenic pentafluoride preparation technology, the present invention provides an arsenic pentafluoride preparation device and preparation method, which can achieve the synthesis of arsenic pentafluoride with high yield and high conversion rate, mild and controllable reaction conditions, high production safety, low equipment maintenance cost, high product purity, and can achieve large-scale production, providing a new idea for the industrial synthesis of arsenic pentafluoride.

[0010] The present invention is specifically achieved through the following technical solutions. According to the present invention, an arsenic pentafluoride preparation device includes a fluorine gas collection tank, a first reactor, a second reactor, a distillation tower, a heat exchanger, an arsenic trifluoride collection cylinder, a product collection cylinder, a first adsorption tower, and a second adsorption tower; the fluorine gas collection tank is connected to the first reactor and the second reactor, the first reactor outlet is connected to the second reactor, the second reactor outlet is connected to the first inlet of the distillation tower, the first outlet of the distillation tower is connected to the arsenic trifluoride collection cylinder, the second outlet of the distillation tower is connected to the inlet of the heat exchanger, the first outlet of the heat exchanger is connected to the second inlet of the distillation tower and the first inlet of the product collection cylinder through a three-way needle valve, the second outlet of the heat exchanger is connected to the second inlet of the product collection cylinder, the outlet of the product collection cylinder is connected to the inlet of the first adsorption tower, the outlet of the first adsorption tower is connected to the inlet of the second adsorption tower, and the second adsorption tower is provided with a vent.

[0011] The aforementioned arsenic pentafluoride production apparatus includes a material tray within the first reactor for holding the reaction raw materials, and a plurality of baffles within the second reactor, with 5 to 20 baffles. The baffle diameter is smaller than the inner diameter of the second reactor, and adjacent baffles are staggered. The baffles are defined as having a fixed end and a free end, respectively. The fixed end is fixed to the inner wall of the second reactor. The fixed ends of adjacent baffles are positioned opposite each other, with the free ends of the baffles positioned below or above the fixed ends of adjacent baffles. The spacing between adjacent baffles may be equal or unequal.

[0012] In the aforementioned arsenic pentafluoride preparation device, the first outlet of the heat exchanger is arranged at the bottom of the heat exchanger, and the second outlet of the heat exchanger is arranged at the top of the heat exchanger.

[0013] In the aforementioned arsenic pentafluoride preparation device, the first outlet of the heat exchanger is connected to the three-way needle valve through the twelfth pipeline, the twelfth pipeline is also provided with a detection port, the three-way needle valve is connected to the second inlet of the distillation tower through the seventh pipeline, and the three-way needle valve is also connected to the first inlet of the product collection cylinder through the eighth pipeline.

[0014] In the aforementioned arsenic pentafluoride preparation device, a partition plate is provided in the product collection cylinder, which divides the inner cavity of the product collection cylinder into a first chamber and a second chamber. The top of the partition plate is connected to the top of the product collection cylinder so that the bottom of the first chamber is connected to the bottom of the second chamber. The first inlet and the second inlet of the product collection cylinder are both connected to the top of the first chamber, and the outlet of the product collection cylinder is connected to the top of the second chamber.

[0015] In the aforementioned arsenic pentafluoride preparation device, the second reactor, distillation tower, heat exchanger, arsenic trifluoride collection cylinder, and product collection cylinder are all provided with jackets, and the jackets are provided with a refrigerant inlet and a refrigerant outlet. The refrigerant in the jackets of the second reactor, distillation tower, heat exchanger, and arsenic trifluoride collection cylinder is industrial alcohol; the refrigerant in the jacket of the product collection cylinder is liquid nitrogen.

[0016] The present invention also provides a method for preparing arsenic pentafluoride, which is implemented using the aforementioned arsenic pentafluoride preparation device and specifically comprises the following steps: (1) Place the reaction raw materials in the tray of the first reactor, seal the first reactor and the second reactor and evacuate to -0.1 ~ -0.09 MPa, preheat the first reactor to 50 ~ 100 ° C, and control the temperature of the second reactor at -50 ~ 30 ° C. First, introduce fluorine gas into the first reactor. When the pressure of the first reactor reaches 0.01 MPa, introduce fluorine gas into the second reactor, and control the pressure of the second reactor at -0.01 ~ 0.01 MPa; Fluorine gas enters the first reactor and reacts with arsenic to generate gaseous arsenic pentafluoride. The reaction temperature of the first reactor is controlled at 100 to 300°C and the pressure is controlled at -0.01 to 0.01 MPa. The product arsenic pentafluoride, a small amount of by-product arsenic trifluoride, and impurity gases enter the second reactor. In the second reactor, the small amount of by-product arsenic trifluoride is separated from the product arsenic pentafluoride, and the product arsenic pentafluoride and the remaining impurity gases enter the distillation tower. (2) The top temperature of the distillation tower is set to -20 ~ -10 °C, and the bottom temperature is set to -40 ~ -20 °C. Arsenic pentafluoride and impurity gases purified by the distillation tower enter the heat exchanger; (3) The temperature of the heat exchanger is maintained at -75 ~ -60℃. Arsenic pentafluoride condenses into liquid in the heat exchanger and accumulates at the bottom of the heat exchanger. The impurity gas enters the product collection cylinder; (4) The purity of the liquefied arsenic pentafluoride is detected through the detection port. When the purity is less than 99%, the liquefied arsenic pentafluoride enters the distillation tower for further distillation and purification; when the purity is not less than 99%, the liquefied arsenic pentafluoride enters the product collection cylinder; (5) The temperature of the product collection cylinder is controlled at -160 ~ -150℃, and arsenic pentafluoride is stored in solid form after entering; the impurity gas enters the first adsorption tower and the second adsorption tower in turn after passing through the product collection cylinder, and is finally discharged.

[0017] In the aforementioned method for preparing arsenic pentafluoride, the reaction raw materials are powdered, granular or block arsenic, or a blend of potassium fluoride, sodium fluoride and arsenic that does not react with fluorine gas, and the volume concentration of fluorine gas introduced into the first reactor and the second reactor is 5-100%.

[0018] In the aforementioned method for preparing arsenic pentafluoride, the flow rate of fluorine gas entering the first reactor is 0.5-100 L / min, and the flow rate entering the second reactor is 0.05-100 L / min.

[0019] In the above-mentioned method for preparing arsenic pentafluoride, fluorine gas can be introduced into the first reactor and the second reactor simultaneously, or it can be introduced into the first reactor first, and then introduced into the second reactor when the pressure of the first reactor reaches 0.01 MPa.

[0020] Compared with the prior art, the present invention has obvious advantages and beneficial effects. By means of the above technical solution, the present invention can achieve considerable technological advancement and practicality, and has a wide range of utilization value. It has at least the following advantages: The present invention addresses the gaps in existing arsenic pentafluoride production technology and provides an arsenic pentafluoride production device and method. The arsenic pentafluoride production device utilizes a two-stage reactor. Fluorine gas enters the first reactor to react with the arsenic feedstock to produce arsenic pentafluoride. The fluorine production temperature in the first reactor is controlled between 100 and 300°C. The product, by-products, and impurity gases enter the second reactor. The by-product, arsenic trifluoride, is separated by controlling the temperature of the second reactor. From the second reactor, the product arsenic pentafluoride and impurity gases enter a distillation tower for purification. The purified arsenic pentafluoride enters a heat exchanger for liquefaction. Once the purity reaches over 99%, it is then transferred to a product collection cylinder, ensuring a purity of over 99%. The impurity gases enter the low-temperature product collection cylinder before entering an adsorption tower, ensuring that the gas entering the adsorption tower contains no arsenic compounds, preventing arsenic compounds from entering the air.

[0021] The preparation apparatus of the present invention satisfies the requirement for excess fluorine gas, reduces byproduct generation, improves fluorine gas utilization and arsenic conversion, and enables high separation from byproducts. Combined with distillation tower purification, high-purity arsenic pentafluoride can be produced. The preparation apparatus and preparation method of the present invention do not require high temperature and high pressure conditions, offer mild and controllable reaction conditions, high production safety, simple post-processing operations, minimal equipment loss, low maintenance costs, high raw material conversion rates, and high product purity, enabling large-scale production. These methods provide new approaches for the industrial synthesis of arsenic pentafluoride. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the arsenic pentafluoride preparation device of the present invention.

[0023] Component number description: 1-Fluorine gas collection tank, 2-First reactor, 3-Second reactor, 4-Distillation tower, 5-Heat exchanger, 6-Arsenic trifluoride collection cylinder, 7-Product collection cylinder, 8-First adsorption tower, 9-Second adsorption tower, 10-Jacket, 11-First pipeline, 12-Second pipeline, 13-Third pipeline, 14-Fourth pipeline, 15-Fifth pipeline, 16-Sixth pipeline, 17-Seventh pipeline, 18-Eighth pipeline, 19-Ninth pipeline, 20-Tenth pipeline, 21-Eleventh pipeline, 22-Twelfth pipeline, 23-Flow meter, 2.1-Material tray, 2.2-First fluorine inlet, 2.3-First reactor outlet, 3.1-Second reactor first inlet, 3.2-Second reactor second inlet Inlet, 3.3-baffle, 3.31-fixed end, 3.32-suspended end, 3.4-second reactor outlet, 4.1-first inlet of distillation tower, 4.2-second inlet of distillation tower, 4.3-first outlet of distillation tower, 4.4-second outlet of distillation tower, 5.1-heat exchanger inlet, 5.2-first outlet of heat exchanger, 5.3-second outlet of heat exchanger, 7.1-first inlet of product collecting cylinder, 7.2-second inlet of product collecting cylinder, 7.3-outlet of product collecting cylinder, 7.4-partition plate, 7.5-first chamber, 7.6-second chamber, 8.1-first adsorption tower inlet, 8.2-first adsorption tower outlet, 9.1-secondary adsorption tower inlet, 9.2-vent, 22.1-detection port. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0025] like Figure 1 As shown, the arsenic pentafluoride preparation device provided by the present invention includes a fluorine gas collection tank 1, a first reactor 2, a second reactor 3, a distillation tower 4, a heat exchanger 5, an arsenic trifluoride collection cylinder 6, a product collection cylinder 7, a primary adsorption tower 8, and a secondary adsorption tower 9.

[0026] The first reactor 2 is a tubular reactor, which is provided with a material tray 2.1 for holding the reaction raw materials. A first fluorine inlet 2.2 is provided on one side of the first reactor, and the first fluorine inlet is connected to the fluorine gas collection tank through a first pipeline 11. The first reactor outlet 2.3 is connected to the second reactor first inlet 3.1 through a second pipeline 12. In one embodiment, the second reactor first inlet is provided at the bottom of the second reactor, such as Figure 1 shown.

[0027] In one embodiment, the tray is a nickel tray, but this description is not to be considered as limiting the present invention.

[0028] The second reactor is also provided with a second inlet 3.2, which is connected to the fluorine gas collection tank via a third pipeline 13. Figure 1 In the embodiment shown, the second inlet 3.2 is arranged as follows Figure 1 The lower portion of the side wall of the second reactor is shown.

[0029] The second reactor is also provided with baffles 3.3, the number of which is 5 to 20, the diameter of which is smaller than the inner diameter of the second reactor, and two adjacent baffles are staggered. Figure 1 As shown, the two ends of the baffle are defined as a fixed end 3.31 and a suspended end 3.32, the fixed end is fixed to the inner wall of the second reactor, the fixed ends of two adjacent baffles are arranged opposite to each other, and the suspended end of the baffle is located below or above the fixed end of the adjacent baffle.

[0030] In one embodiment, the spacing between two adjacent baffles is equal. In other embodiments, the spacing between two adjacent baffles may be unequal according to actual needs.

[0031] The second reactor is topped with a second reactor outlet 3.4, which is connected to the first inlet 4.1 of the distillation tower via a fourth pipeline 14. The distillation tower is also equipped with a second inlet 4.2, a first outlet 4.3, and a second outlet 4.4. The first and second inlets 4.1, 4.2 are located at the lower side of the distillation tower, with the second inlet 4.2 located opposite the first inlet 4.1. The first outlet 4.3 is located at the bottom of the distillation tower, while the second outlet 4.4 is located at the top. The first outlet 4.3 is connected to the arsenic trifluoride collection cylinder 6 via a fifth pipeline 15, while the second outlet 4.4 is connected to the heat exchanger inlet 5.1 via a sixth pipeline 16. The distillation tower is equipped with stainless steel theta ring packing.

[0032] The heat exchanger is also provided with a first heat exchanger outlet 5.2 and a second heat exchanger outlet 5.3. The first heat exchanger outlet 5.2 is located at the bottom of the heat exchanger, and the second heat exchanger outlet 5.3 is located at the top of the heat exchanger. In a preferred embodiment, the heat exchanger inlet and the two heat exchanger outlets are located at opposite ends of the heat exchanger. For example, the heat exchanger inlet is located on the left side of the heat exchanger, and the first heat exchanger outlet 5.2 and the second heat exchanger outlet 5.3 are both located on the right side of the heat exchanger. In a preferred embodiment, the end where the heat exchanger inlet is located is slightly higher than the end where the second heat exchanger outlet 5.3 is located, forming a slope at the bottom of the heat exchanger, facilitating the outflow of condensed liquid within the heat exchanger through the first heat exchanger outlet. In other embodiments, the first heat exchanger outlet may also be located at the bottom of the header on the right side of the heat exchanger. The first outlet of the heat exchanger is connected to the three-way needle valve through the twelfth pipeline 22, and the three-way needle valve is also connected to the second inlet 4.2 of the distillation tower through the seventh pipeline 17. Moreover, the three-way needle valve is also connected to the first inlet 7.1 of the product collection cylinder through the eighth pipeline 18. The twelfth pipeline is also provided with a detection port 22.1.

[0033] The second outlet 5.3 of the heat exchanger is connected to the second inlet 7.2 of the product collection cylinder via a ninth pipeline 19. The outlet 7.3 of the product collection cylinder is connected to the inlet 8.1 of the first adsorption tower via a tenth pipeline 20. The outlet 8.2 of the first adsorption tower is connected to the inlet 9.1 of the second adsorption tower via an eleventh pipeline 21. A vent 9.2 is provided at the top of the second adsorption tower.

[0034] The first inlet 7.1 of the product collecting cylinder, the second inlet 7.2 of the product collecting cylinder, and the outlet 7.3 of the product collecting cylinder are all arranged at the top of the product collecting cylinder.

[0035] Furthermore, a partition plate 7.4 is installed within the product collection cylinder, dividing the interior of the product collection cylinder into a first chamber 7.5 and a second chamber 7.6. The partition plate is axially aligned with the axis of the product collection cylinder, and its axial length is approximately two-thirds of the axial length of the product collection cylinder. For example, if both the product collection cylinder and the partition plate are oriented vertically, the top of the partition plate is connected to the top of the product collection cylinder, while the bottom of the partition plate is free from contact with the bottom of the product collection cylinder. This creates a left-right distribution of the first and second chambers, with the bottom of the first chamber connected to the bottom of the second chamber. The first and second inlets 7.1 and 7.2 of the product collection cylinder are both connected to the top of the first chamber, while the outlet 7.3 of the product collection cylinder is connected to the top of the second chamber.

[0036] The primary adsorption tower inlet 8.1 is located at the bottom of the primary adsorption tower or at the lower portion of the primary adsorption tower sidewall, and the primary adsorption tower outlet 8.2 is located at the top of the primary adsorption tower or at the upper portion of the primary adsorption tower sidewall. The secondary adsorption tower inlet 8.1 is located at the bottom of the secondary adsorption tower or at the lower portion of the secondary adsorption tower sidewall, and the vent 8.2 is located at the top of the secondary adsorption tower or at the upper portion of the secondary adsorption tower sidewall, preferably at the top of the secondary adsorption tower.

[0037] Furthermore, valves are provided on the first pipeline, the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, the sixth pipeline, the ninth pipeline, the tenth pipeline, the eleventh pipeline and the twelfth pipeline for controlling the on and off of the pipelines, and the twelfth pipeline is connected to the seventh pipeline and the eighth pipeline through a three-way needle valve.

[0038] Flow meters 23 are also provided on the first pipeline and the third pipeline to control the flow rate of the fluorine gas entering the first reactor and the second reactor.

[0039] The first reactor, second reactor, heat exchanger, distillation column, arsenic trifluoride collection cylinder, and product collection cylinder are equipped with thermometers and pressure gauges to measure the temperature and pressure within these cylinders. The top and bottom of the distillation column are equipped with thermometers to measure the top and bottom temperatures, respectively.

[0040] The second reactor, distillation column, heat exchanger, arsenic trifluoride collection cylinder, and product collection cylinder are all equipped with jackets 10, each with a refrigerant inlet and outlet. Refrigerant is passed through the jackets of the second reactor, distillation column, heat exchanger, and arsenic trifluoride collection cylinder to maintain the temperatures of the respective reactors at a set value. Industrial alcohol can be used as the refrigerant.

[0041] More specifically, the refrigerant in the jackets of the second reactor, the distillation tower, and the arsenic trifluoride collection cylinder enters from the bottom and exits from the top. The refrigerant inlet in the heat exchanger jacket is close to the first outlet of the heat exchanger, and the refrigerant outlet is close to the inlet of the heat exchanger.

[0042] Liquid nitrogen is passed through the jacket of the product collection cylinder to control the temperature of the product collection cylinder at -160 ~ -150℃, and the liquid nitrogen is fed in from the bottom and discharged from the top.

[0043] Furthermore, the seventh pipeline and the eighth pipeline may also be covered with a jacket, and a refrigerant is passed through the jacket to reduce the temperature of the seventh pipeline and the eighth pipeline to ensure the transportation of the liquefied product.

[0044] In the arsenic pentafluoride preparation apparatus of the present invention, all equipment and pipelines that come into contact with the product arsenic pentafluoride are made of corrosion-resistant materials, such as monel, stainless steel, and other corrosion-resistant materials. A passivation treatment is required before the preparation process begins. The passivation treatment can be performed by passing a fluorine-nitrogen mixed gas. After the entire apparatus system is evacuated, a mixed gas of fluorine and nitrogen is introduced. The mass concentration of fluorine in the mixed gas is 10-20%, and the remainder is nitrogen. The passivation time is 24 hours.

[0045] The process for preparing arsenic pentafluoride by the above arsenic pentafluoride preparation device includes: (1) Place the reaction raw materials in the tray of the first reactor. The reaction raw materials are arsenic (in powder, granular or block form), or a mixture of potassium fluoride, sodium fluoride and arsenic that does not react with fluorine gas. After the first reactor and the second reactor are sealed and qualified, evacuate to -0.1 ~ -0.09 MPa. Preheat the first reactor to 50 ~ 100℃, and control the temperature of the second reactor at -50 ~ 30℃. First, introduce fluorine gas into the first reactor. When the pressure of the first reactor reaches 0.01 MPa, introduce fluorine gas into the second reactor. The pressure of the second reactor is controlled at -0.01 ~ 0.01 MPa.

[0046] Fluorine gas enters the first reactor and reacts with arsenic to produce gaseous arsenic pentafluoride. The reaction temperature in the first reactor is controlled between 100°C and 300°C, and the pressure is controlled between -0.01 and 0.01 MPa. The reaction product, arsenic pentafluoride, a small amount of byproduct arsenic trifluoride, and other impurities (such as unreacted fluorine gas, nitrogen, and a small amount of nitrogen in the fluorine gas collection tank) enter the second reactor through a second pipeline. The temperature of the second reactor is controlled between -50°C and 30°C. This low temperature can be controlled by introducing a refrigerant into the jacket of the second reactor. The boiling points of arsenic pentafluoride are -52.8°C, arsenic trifluoride is 63°C, fluorine gas is -188.12°C, and nitrogen is -196°C. In the second reactor, the small amount of byproduct arsenic trifluoride is condensed and separated from the product arsenic pentafluoride. Fluorine gas enters the second reactor, providing an excess of fluorine and reacting with any remaining uncondensed arsenic trifluoride in the second reactor to produce arsenic pentafluoride. The remaining gas exits the second reactor via a fourth pipeline and enters the distillation column. The gas entering the distillation column includes the product arsenic pentafluoride, nitrogen, unreacted fluorine, and any remaining unreacted, uncondensed arsenic trifluoride.

[0047] (2) The top temperature of the distillation tower is set at -20 to -10°C, and the bottom temperature is set at -40 to -20°C. If the gas entering the distillation tower contains a small amount of arsenic trifluoride, the arsenic trifluoride is condensed in the distillation tower to achieve further separation from the product arsenic pentafluoride. After purification in the distillation tower, the arsenic pentafluoride and impurity gases (such as unreacted fluorine and nitrogen) enter the heat exchanger from the second outlet at the top of the distillation tower.

[0048] (3) A refrigerant is passed through the heat exchanger jacket to keep the heat exchanger temperature at -75 ~ -60 °C. Arsenic pentafluoride condenses into liquid in the heat exchanger and accumulates near the first outlet of the heat exchanger. The impurity gas enters the product collection cylinder from the second outlet of the heat exchanger through the ninth pipeline.

[0049] (4) The purity of the liquefied arsenic pentafluoride is tested through the detection port on the twelfth pipeline. If the purity is less than 99%, the liquefied arsenic pentafluoride is returned to the distillation tower through the seventh pipeline by controlling the three-way needle valve for further distillation and purification. If the purity of the liquefied arsenic pentafluoride is not less than 99%, the three-way needle valve is controlled to allow the liquefied arsenic pentafluoride to enter the product collection cylinder through the eighth pipeline.

[0050] (5) The temperature of the product collection cylinder is controlled at -160 ~ -150℃. Arsenic pentafluoride is stored in solid form after entering. Impurity gases (such as unreacted fluorine gas, nitrogen, etc.) pass through the first chamber and the second chamber of the product collection cylinder in sequence, are discharged from the outlet of the product collection cylinder, and enter the first adsorption tower and the second adsorption tower in sequence. After adsorption and neutralization in the two-stage adsorption tower, they are finally discharged. The adsorbent in the first adsorption tower and the second adsorption tower can be a mixture of one or more of sodium hydroxide, calcium hydroxide, sodium oxide, calcium oxide, and sodium fluoride.

[0051] In step (1), the entire device system can be vacuumed through the vent of the secondary adsorption tower.

[0052] In step (1), fluorine gas can be introduced into the first reactor and the second reactor simultaneously, or it can be introduced into the first reactor first, and then introduced into the second reactor after the pressure of the first reactor reaches 0.01 MPa. The flow rate of fluorine gas entering the first reactor can be 0.5-100 L / min, and the flow rate of fluorine gas entering the second reactor can be 0.05-100 L / min.

[0053] The fluorine gas in the fluorine gas collection tank is produced on-site. It is prepared according to conventional electrolytic fluorine production processes, purified according to conventional procedures, and then passed into the fluorine gas collection tank. The volume concentration of fluorine gas in the fluorine gas collection tank ranges from 5% to 100%. Fluorine gas obtained from electrolytic fluorine production can be used directly for the reaction, or it can be diluted with nitrogen and used as fluorine for the reaction. When the fluorine concentration is low, a catalyst can be added to the first and second reactors.

[0054] In the above preparation process, after the reaction is completed, the temperature of the second reactor returns to room temperature, and the arsenic trifluoride condensed in the second reactor is liquefied and returned to the first reactor to participate in the next preparation process of arsenic pentafluoride.

[0055] Throughout the preparation process, the valve on the fifth pipeline is closed, and the amount of arsenic trifluoride condensed in the distillation tower is very small. After the reaction is complete and the temperature of the distillation tower rises, the valve on the fifth pipeline is opened, and the arsenic trifluoride liquefies and enters the arsenic trifluoride collection cylinder through the fifth pipeline for storage. The temperature of the arsenic trifluoride collection cylinder is maintained at -50 to -40°C. The three-way needle valve selects whether to connect to the seventh pipeline or the eighth pipeline based on the test results of the test port.

[0056] The diameters of the first and second inlets of the product collection cylinder should be larger, and both can only be set at the top of the product collection cylinder. Otherwise, arsenic pentafluoride solidifies at a temperature of -160 ~ -150℃ and easily blocks the first and second inlets of the product collection cylinder.

[0057] Arsenic pentafluoride was prepared according to the above method using different process parameters. In the following examples, fluorine gas was prepared by an existing conventional electrolytic fluorine production process, and arsenic was purchased from Shaanxi Didu Pharmaceutical Chemical Co., Ltd., but this description is not to be construed as limiting the present invention.

[0058] Example 1 1000 g of arsenic was placed in the nickel tray of the first reactor. After the first and second reactors were sealed, they were evacuated to -0.1 to -0.09 MPa. The first reactor was preheated to 50°C, and the second reactor was cooled to 0°C. Fluorine gas was first introduced into the first reactor at a flow rate of 0.43 L / min. When the pressure in the first reactor reached 0.01 MPa, fluorine gas was introduced into the second reactor at a flow rate of 0.05 L / min. The reaction temperature in the first reactor was controlled at 150°C, and the temperature in the second reactor was controlled at 0°C. Fluorine was continuously introduced into the first and second reactors for 29 hours. The top temperature of the distillation column was maintained at -20°C, and the bottom temperature at -40°C. After purification in the distillation column, arsenic pentafluoride and other impurity gases (such as unreacted fluorine and nitrogen) were discharged into a heat exchanger through the second outlet at the top of the distillation column. The heat exchanger temperature was maintained at -75°C. The arsenic pentafluoride condensed into a liquid in the heat exchanger and accumulated near the first outlet of the heat exchanger. The impurity gases were discharged from the second outlet of the heat exchanger through the ninth pipeline into a product collection cylinder. Based on the test results at the inspection port, the liquefied arsenic pentafluoride in the heat exchanger is either returned to the distillation tower for further purification (arsenic pentafluoride purity less than 99%) or collected in a product collection cylinder (arsenic pentafluoride purity not less than 99%). The product collection cylinder is kept at -150°C, and the arsenic pentafluoride is stored in a solid state. Impurity gases (fluorine and nitrogen) enter the primary and secondary adsorption towers before being exhausted.

[0059] The number of baffles in the second reactor is 10, and the adsorbent in the primary adsorption tower and the secondary adsorption tower is sodium hydroxide.

[0060] After testing, the purity of arsenic pentafluoride entering the product collection cylinder was 99.2%, and the yield calculated based on the arsenic conversion rate was 83.5%.

[0061] Example 2 2000 g of arsenic was placed in the nickel tray of the first reactor. After the first and second reactors were sealed, they were evacuated to -0.1 to -0.09 MPa. The first reactor was preheated to 70°C, and the second reactor was cooled to -25°C. Fluorine gas was first introduced into the first reactor at a flow rate of 0.64 L / min. After the pressure in the first reactor reached 0.01 MPa, fluorine gas was introduced into the second reactor at a flow rate of 0.07 L / min. The reaction temperatures of the first reactor and the second reactor were controlled at 100°C and -25°C, respectively. Fluorine was continuously introduced into the first and second reactors for 38 hours. The top temperature of the distillation column was maintained at -15°C, and the bottom temperature was maintained at -30°C. After purification in the distillation column, the arsenic pentafluoride and other impurities (e.g., unreacted fluorine and nitrogen) were passed through the second outlet at the top of the distillation column into a heat exchanger. The heat exchanger temperature is -70°C. Arsenic pentafluoride condenses into a liquid in the heat exchanger and accumulates near the first outlet. Impurity gases enter the product collection cylinder from the second outlet via the ninth pipeline. Based on the test results at the detection port, the liquefied arsenic pentafluoride in the heat exchanger is either returned to the distillation tower for further purification (arsenic pentafluoride purity less than 99%) or collected in the product collection cylinder (arsenic pentafluoride purity not less than 99%). The product collection cylinder is kept at -150°C, and the arsenic pentafluoride is stored in a solid state. Impurity gases (fluorine and nitrogen) enter the primary and secondary adsorption towers before being discharged.

[0062] The number of baffles in the second reactor is 15, and the adsorbent in the primary adsorption tower and the secondary adsorption tower is sodium oxide.

[0063] After testing, the purity of arsenic pentafluoride entering the product collection cylinder was 99.5%, and the yield calculated based on the arsenic conversion rate was 84.2%.

[0064] Example 3 3000 g of arsenic was placed in the nickel tray of the first reactor. After the first and second reactors were sealed, they were evacuated to -0.1 to -0.09 MPa. The first reactor was preheated to 100°C, and the second reactor was cooled to -45°C. Fluorine gas was first introduced into the first reactor at a flow rate of 0.85 L / min. After the pressure in the first reactor reached 0.01 MPa, fluorine gas was introduced into the second reactor at a flow rate of 0.09 L / min. The reaction temperatures in the first reactor and the second reactor were controlled at 250°C and -45°C, respectively. Fluorine was continuously introduced into the first and second reactors for 43 hours. The top temperature of the distillation column was maintained at -10°C, and the bottom temperature was maintained at -20°C. After purification in the distillation column, the arsenic pentafluoride and other impurities (e.g., unreacted fluorine and nitrogen) were passed through the second outlet at the top of the distillation column into a heat exchanger. The heat exchanger temperature is -60°C. Arsenic pentafluoride condenses into a liquid in the heat exchanger and accumulates near the first outlet. Impurity gases enter the product collection cylinder from the second outlet via the ninth pipeline. Based on the test results at the detection port, the liquefied arsenic pentafluoride in the heat exchanger is either returned to the distillation tower for further purification (arsenic pentafluoride purity less than 99%) or collected in the product collection cylinder (arsenic pentafluoride purity not less than 99%). The product collection cylinder is kept at -160°C, and the arsenic pentafluoride is stored in a solid state. Impurity gases (fluorine and nitrogen) enter the primary and secondary adsorption towers before being discharged.

[0065] The number of baffles in the second reactor is 20, and the adsorbent in the primary adsorption tower and the secondary adsorption tower is calcium oxide.

[0066] After testing, the purity of arsenic pentafluoride entering the product collection cylinder was 99.4%, and the yield calculated based on the arsenic conversion rate was 84.7%.

[0067] Example 4 1000 g of arsenic was placed in the nickel tray of the first reactor. After the first and second reactors were sealed, they were evacuated to -0.1 to -0.09 MPa. The first reactor was preheated to 60°C, and the second reactor was cooled to -10°C. Fluorine gas was first introduced into the first reactor at a flow rate of 0.52 L / min. When the pressure in the first reactor reached 0.01 MPa, fluorine gas was introduced into the second reactor at a flow rate of 0.06 L / min. The reaction temperatures of the first reactor and the second reactor were maintained at 200°C and -10°C, respectively. Fluorine was continuously introduced into the first and second reactors for 23 hours. The top temperature of the distillation column was maintained at -10°C, and the bottom temperature was maintained at -25°C. After purification in the distillation column, the arsenic pentafluoride and other impurities (e.g., unreacted fluorine and nitrogen) were passed through the second outlet at the top of the distillation column into a heat exchanger. The heat exchanger temperature is -65°C. Arsenic pentafluoride condenses into a liquid in the heat exchanger and accumulates near the first outlet. Impurity gases enter the product collection cylinder from the second outlet via the ninth pipeline. Based on the test results at the detection port, the liquefied arsenic pentafluoride in the heat exchanger is either returned to the distillation tower for further purification (arsenic pentafluoride purity less than 99%) or collected in the product collection cylinder (arsenic pentafluoride purity not less than 99%). The product collection cylinder is kept at -150°C, and the arsenic pentafluoride is stored in a solid state. Impurity gases (fluorine and nitrogen) enter the primary and secondary adsorption towers before being discharged.

[0068] The number of baffles in the second reactor is 18, and the adsorbent in the primary adsorption tower and the secondary adsorption tower is calcium hydroxide.

[0069] After testing, the purity of arsenic pentafluoride entering the product collection cylinder was 99.3%, and the yield calculated based on the arsenic conversion rate was 83.9%.

[0070] The calculated results for the arsenic feed mass (g), arsenic pentafluoride yield (g), and arsenic conversion rate w for Examples 1 to 4 are shown in Table 1. Arsenic conversion rate w = (m2 / m1) × 100%, where m1 is the arsenic feed mass and m2 is the mass of arsenic actually reacted. m2 is calculated based on the reaction equation and the arsenic pentafluoride yield.

[0071] Table 1. Arsenic conversion rates in Examples 1 to 4 Arsenic feed mass / g Arsenic pentafluoride production / g Arsenic conversion rate / % Example 1 1000 1894.81 83.5 Example 2 2000 3819.23 84.2 Example 3 3000 5762.35 84.7 Example 4 1000 1903.78 83.9 The above description is merely an embodiment of the present invention and does not constitute any form of limitation to the present invention. The present invention may also have other forms of embodiments based on the above structures and functions, which are not listed here one by one. Therefore, any simple modification, equivalent changes, and modifications made to the above embodiments by any person skilled in the art in accordance with the technical essence of the present invention without departing from the scope of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. An arsenic pentafluoride preparation device, characterized in that: The invention comprises a fluorine gas collecting tank (1), a first reactor (2), a second reactor (3), a distillation tower (4), a heat exchanger (5), an arsenic trifluoride collecting cylinder (6), a product collecting cylinder (7), a first adsorption tower (8), and a second adsorption tower (9); the fluorine gas collecting tank (1) is connected to the first reactor and the second reactor, the first reactor outlet is connected to the second reactor, the second reactor outlet is connected to the first inlet (4.1) of the distillation tower, the first outlet (4.3) of the distillation tower is connected to the arsenic trifluoride collecting cylinder (6), and the distillation tower outlet is connected to the first inlet (4.1) of the distillation tower. The second outlet (4.4) is connected to the inlet (5.1) of the heat exchanger. The first outlet (5.2) of the heat exchanger is connected to the second inlet (4.2) of the distillation tower and the first inlet (7.1) of the product collection cylinder through a three-way needle valve. The second outlet (5.3) of the heat exchanger is connected to the second inlet (7.2) of the product collection cylinder. The outlet (7.3) of the product collection cylinder is connected to the inlet (8.1) of the first adsorption tower. The outlet (8.2) of the first adsorption tower is connected to the inlet (9.1) of the second adsorption tower. The second adsorption tower is provided with a vent (9.2).

2. The arsenic pentafluoride preparation device according to claim 1, characterized in that: A material tray (2.1) is provided in the first reactor for holding reaction raw materials, and a plurality of baffles are provided in the second reactor. The diameter of the baffles is smaller than the inner diameter of the second reactor, and two adjacent baffles are staggered.

3. The arsenic pentafluoride preparation device according to claim 1, characterized in that: The first outlet of the heat exchanger is arranged at the bottom of the heat exchanger, and the second outlet of the heat exchanger is arranged at the top of the heat exchanger.

4. The arsenic pentafluoride preparation device according to claim 1 or 3, characterized in that: The first outlet of the heat exchanger is connected to the three-way needle valve via the twelfth pipeline (22), and a detection port is also provided on the twelfth pipeline.

5. The arsenic pentafluoride preparation device according to claim 1, characterized in that: A partition plate (7.4) is provided in the product collection cylinder, and the partition plate divides the inner cavity of the product collection cylinder into a first chamber (7.5) and a second chamber (7.6). The top of the partition plate is connected to the top of the product collection cylinder so that the bottom of the first chamber is connected to the bottom of the second chamber. The first inlet of the product collection cylinder and the second inlet of the product collection cylinder are both connected to the top of the first chamber, and the outlet of the product collection cylinder is connected to the top of the second chamber.

6. The arsenic pentafluoride preparation device according to claim 1, characterized in that: The second reactor, the distillation tower, the heat exchanger, the arsenic trifluoride collecting cylinder, and the product collecting cylinder are all provided with a jacket (10), and a refrigerant inlet and a refrigerant outlet are provided on the jacket. The refrigerant in the jackets of the second reactor, the distillation tower, the heat exchanger, and the arsenic trifluoride collecting cylinder is industrial alcohol; and the refrigerant in the jacket of the product collecting cylinder is liquid nitrogen.

7. A method for preparing arsenic pentafluoride, characterized in that: The following steps are involved: (1) Place the reaction raw materials in the tray of the first reactor, seal the first reactor and the second reactor and evacuate to -0.1 ~ -0.09 MPa, preheat the first reactor to 50 ~ 100 ° C, and control the temperature of the second reactor at -50 ~ 30 ° C. First, introduce fluorine gas into the first reactor. When the pressure of the first reactor reaches 0.01 MPa, introduce fluorine gas into the second reactor, and control the pressure of the second reactor at -0.01 ~ 0.01 MPa; Fluorine gas enters the first reactor and reacts with arsenic to generate gaseous arsenic pentafluoride. The reaction temperature of the first reactor is controlled at 100-300°C and the pressure is controlled at -0.01-0.01 MPa. The product arsenic pentafluoride, a small amount of by-product arsenic trifluoride, and impurity gases enter the second reactor. In the second reactor, a small amount of by-product arsenic trifluoride is separated from the product arsenic pentafluoride, and the product arsenic pentafluoride and the remaining impurity gases enter the distillation tower. (2) The top temperature of the distillation tower is set to -20 ~ -10 °C, and the bottom temperature is set to -40 ~ -20 °C. Arsenic pentafluoride and impurity gases purified by the distillation tower enter the heat exchanger; (3) The temperature of the heat exchanger is maintained at -75 ~ -60℃. Arsenic pentafluoride condenses into liquid in the heat exchanger and accumulates at the bottom of the heat exchanger. The impurity gas enters the product collection cylinder; (4) The purity of the liquefied arsenic pentafluoride is detected through the detection port. When the purity is less than 99%, the liquefied arsenic pentafluoride enters the distillation tower for further distillation and purification; when the purity is not less than 99%, the liquefied arsenic pentafluoride enters the product collection cylinder; (5) The temperature of the product collection cylinder is controlled at -160 ~ -150℃, and arsenic pentafluoride is stored in solid form after entering; the impurity gas enters the first adsorption tower and the second adsorption tower in turn after passing through the product collection cylinder, and is finally discharged.

8. The method for preparing arsenic pentafluoride according to claim 7, wherein: The reaction raw materials are powdered, granular or block arsenic, or a mixture of potassium fluoride, sodium fluoride and arsenic that does not react with fluorine gas. The volume concentration of fluorine gas introduced into the first reactor and the second reactor is 5-100%.

9. The method for preparing arsenic pentafluoride according to claim 7, wherein: The flow rate of fluorine gas entering the first reactor is 0.5~100 L / min, and the flow rate entering the second reactor is 0.05~100 L / min.

10. The method for preparing arsenic pentafluoride according to claim 7, wherein: The fluorine gas is introduced into the first reactor and the second reactor at the same time, or first introduced into the first reactor, and then introduced into the second reactor when the pressure of the first reactor reaches 0.01 MPa.

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