Purification system and purification method of hexafluoro-1,3-butadiene

Abstract

The application provides a hexafluoro-1,3-butadiene purification device system and a purification method. The hexafluoro-1,3-butadiene purification device system is simple in structure, can realize purification of hexafluoro-1,3-butadiene, and can ensure the yield of hexafluoro-1,3-butadiene. Moreover, the purification method corresponds to the purification device system, the operation of the purification method is simple, and the purification of hexafluoro-1,3-butadiene raw materials can be realized by sequentially performing acid removal treatment, first adsorption treatment, second adsorption treatment, first rectification treatment and second rectification treatment, and the purity of obtained hexafluoro-1,3-butadiene can reach more than 99.99%, and the yield can reach more than 68%.

Description

Technical Field

[0001] This invention belongs to the field of purification technology, and relates to a separation and purification device system and purification method for etching gases, particularly to a purification device system and purification method for hexafluoro-1,3-butadiene. Background Technology

[0002] Hexafluoro-1,3-butadiene (C4F6) has a boiling point of 6℃ and a concentration of 1.553 g / mL at -20℃. It is a colorless and odorless gas at room temperature and pressure.

[0003] Hexafluoro-1,3-butadiene has attracted attention as a plasma etching gas for semiconductors. It can etch narrow widths of 100 nm or even narrower, exhibiting faster etching rates, high selectivity, and high aspect ratios. Furthermore, its short atmospheric lifetime and negligible global warming potential compared to traditional etchants make it a highly efficient etchant with low greenhouse effect. Developing separation and purification systems and methods for hexafluoro-1,3-butadiene has significant economic and environmental value.

[0004] Currently, there are two main production processes for hexafluoro-1,3-butadiene in existing technologies. One is to use tetrahalohexafluorobutane, dihalohexafluorobutane, or dihalooctafluorobutane as intermediates to dehalogenate and obtain hexafluoro-1,3-butadiene. The other is to use trifluoroethylene as raw material, react it with zinc to obtain trifluorovinyl zinc bromide intermediate, and then carry out a coupling reaction under the action of a metal oxidant to obtain hexafluoro-1,3-butadiene.

[0005] During the production of hexafluoro-1,3-butadiene, impurities such as fluorochlorobromoalkanes, alkenes, and alcohols are inevitably generated, along with hydrogen fluoride, unnecessary moisture, and impurity gases such as nitrogen, carbon monoxide, and carbon dioxide. To ensure that the obtained hexafluoro-1,3-butadiene meets the requirements of etching gases, it is necessary to remove these impurities.

[0006] US6544319B1 discloses a method for purifying hexafluoro-1,3-butadiene using 5A molecular sieves. After treatment by this method, the purity of hexafluoro-1,3-butadiene can be increased from 99.90% to 99.96%. However, about 0.1 wt% of hexafluoro-2-butyne will be generated during its adsorption purification process, which affects the production yield and purity.

[0007] JP2004339187A discloses a method for purifying hexafluoro-1,3-butadiene using molecular sieves and activated carbon. In this method, the hexafluoro-1,3-butadiene feedstock is passed sequentially through molecular sieves and activated carbon, which can reduce H2O and HF to below 1 ppm. Although the provided method can reduce the content of H2O and HF, it does not involve the removal of other fluorocarbon impurities, and the activated carbon adsorbs a large amount of feedstock, reducing the yield of hexafluoro-1,3-butadiene, making it unsuitable for industrial production.

[0008] It can be seen that the existing purification methods mainly focus on the development of molecular sieves or adsorbents. However, hexafluoro-1,3-butadiene has a diene structure, and it will undergo isomerization or decomposition reactions when it comes into contact with molecular sieves, thereby reducing the yield and purity of hexafluoro-1,3-butadiene. Therefore, it is necessary to adjust the purification devices and purification methods in the existing technology. Summary of the Invention

[0009] The purpose of this invention is to provide a purification device system and purification method for hexafluoro-1,3-butadiene. The purification device system has a simple structure, and the corresponding purification method is also simple. The purity and yield of the purified hexafluoro-1,3-butadiene are both high.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a purification apparatus system for hexafluoro-1,3-butadiene, the purification apparatus system comprising an acid removal device, a first adsorption device, a second adsorption device, a first distillation device, and a second distillation device connected in sequence.

[0012] The first adsorption device is equipped with a first adsorbent for dehydration;

[0013] The second adsorption device is equipped with a second adsorbent that adsorbs both organic and inorganic impurities.

[0014] The hexafluorobutadiene feedstock contains inorganic impurities such as H2O, HF, N2, CO, and CO2, as well as organic impurities such as hexafluoro-2-butyne, octafluoro-2-butene, trifluorobromoethylene, and tetrafluorodibromoethane. This invention uses an acid removal device to remove acidic gases from the hexafluorobutadiene feedstock. Then, a first adsorption treatment is performed in a first adsorption device to remove moisture. Next, a second adsorption treatment is performed in a second adsorption device to adsorb and remove organic and inorganic impurities. Finally, a first distillation treatment is performed in a first distillation device to remove heavy components. The crude product from the top of the distillation column enters a second distillation device for further distillation to remove light components. Purified hexafluoro-1,3-butadiene is obtained at the bottom of the second distillation device.

[0015] Preferably, the acid removal device includes a countercurrent absorption device or a bubbling absorption device.

[0016] Preferably, the acid removal device is equipped with acid removal packing material.

[0017] Preferably, the acid-removing packing includes any one or a combination of at least two of the following: multifaceted hollow spheres, Pall rings, Raschig rings, rectangular saddle rings, conjugate rings, or Heil rings. Typical but non-limiting combinations include combinations of multifaceted hollow spheres and Pall rings, combinations of Raschig rings and rectangular saddle rings, combinations of conjugate rings and Heil rings, combinations of Pall rings, Raschig rings, and rectangular saddle rings, combinations of Raschig rings, rectangular saddle rings, and conjugate rings, or combinations of multifaceted hollow spheres, Pall rings, Raschig rings, rectangular saddle rings, conjugate rings, and Heil rings.

[0018] Preferably, the acid-removing filler is made of any one of polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), or polytetrafluoroethylene (PTFE). Typical but non-limiting combinations include combinations of polyethylene and polypropylene, polypropylene and polyvinyl chloride, polyvinyl chloride and polytetrafluoroethylene, polyethylene, polypropylene and polyvinyl chloride, polypropylene, polyvinyl chloride and polytetrafluoroethylene, or polyethylene, polypropylene, polyvinyl chloride and polytetrafluoroethylene.

[0019] Preferably, the first adsorbent comprises any one or a combination of at least two of anhydrous calcium sulfate, microporous silica gel, anhydrous calcium chloride, or anhydrous copper sulfate. Typical but non-limiting combinations include a combination of anhydrous calcium sulfate and microporous silica gel, a combination of anhydrous calcium chloride and anhydrous copper sulfate, a combination of anhydrous calcium sulfate, anhydrous calcium chloride, and anhydrous copper sulfate, or a combination of anhydrous calcium sulfate, microporous silica gel, anhydrous calcium chloride, and anhydrous copper sulfate.

[0020] Preferably, the second adsorbent comprises any one or a combination of at least two of the following: all-silica molecular sieve, 5A carbon molecular sieve, or activated carbon. Typical but non-limiting combinations include the combination of all-silica molecular sieve and 5A carbon molecular sieve, the combination of 5A carbon molecular sieve and activated carbon, the combination of all-silica molecular sieve and activated carbon, or the combination of all-silica molecular sieve, 5A carbon molecular sieve, and activated carbon.

[0021] The second adsorbent used in this invention includes any one or a combination of at least two of the following: all-silica molecular sieve, 5A carbon molecular sieve, or activated carbon. Since no silica-alumina-based molecular sieve is used, the isomerization or decomposition reaction of the diene-structured hexafluoro-1,3-butadiene at the molecular sieve can be avoided, thus preventing a decrease in the yield and purity of hexafluoro-1,3-butadiene.

[0022] In this invention, the shape of the second adsorbent includes spherical and / or strip-shaped.

[0023] Preferably, the average particle size of the second adsorbent is 2-5 mm, for example, it can be 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] Preferably, the first distillation apparatus is a packed tower.

[0025] Preferably, the second distillation unit is a packed tower.

[0026] The packing materials in the first and second distillation units of this invention are independently either random packing or structured packing.

[0027] The random packing includes any one or a combination of at least two of Pall rings, stepped rings, rectangular saddle rings, or θ rings. Typical but non-limiting combinations include combinations of Pall rings and stepped rings, combinations of rectangular saddle rings and θ rings, combinations of Pall rings, rectangular saddle rings, and θ rings, or combinations of Pall rings, stepped rings, rectangular saddle rings, and θ rings.

[0028] The structured packing includes any one or a combination of at least two of the following: perforated plate corrugated packing, wire mesh corrugated packing, plate corrugated packing, or perforated plate corrugated packing. Typical but non-limiting combinations include a combination of perforated plate corrugated packing and wire mesh corrugated packing, a combination of wire mesh corrugated packing and perforated plate corrugated packing, or a combination of perforated plate corrugated packing, wire mesh corrugated packing, and perforated plate corrugated packing.

[0029] In a second aspect, the present invention provides a method for purifying hexafluoro-1,3-butadiene, wherein the purification method is carried out in the purification apparatus system described in the first aspect, and includes the following steps:

[0030] The hexafluorobutadiene feedstock is subjected to acid removal treatment, first adsorption treatment, second adsorption treatment, first distillation treatment and second distillation treatment in sequence to complete the purification of hexafluoro-1,3-butadiene.

[0031] The acid removal process is carried out in an acid removal device;

[0032] The first adsorption treatment is carried out in the first adsorption device;

[0033] The second adsorption treatment is carried out in the second adsorption device;

[0034] The first distillation process is carried out in a first distillation apparatus;

[0035] The second distillation process is carried out in a second distillation apparatus.

[0036] Preferably, the absorbent used in the acid removal treatment includes any one or a combination of at least two of water, sodium bicarbonate solution, or sodium carbonate solution.

[0037] Preferably, the concentration of the sodium bicarbonate solution is 2-4 wt%, for example, it can be 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt% or 4 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0038] Preferably, the concentration of the sodium carbonate solution is 2-5 wt%, for example, it can be 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, or 5 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0039] Preferably, the temperature of the acid removal treatment is 10-40℃, for example, it can be 10℃, 15℃, 20℃, 25℃, 30℃, 35℃ or 40℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 20-30℃.

[0040] Preferably, the temperature of the first adsorption treatment is 10-40℃, for example, it can be 10℃, 15℃, 20℃, 25℃, 30℃, 35℃ or 40℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 20-30℃.

[0041] Preferably, the volume hourly space velocity (VHSV) of the first adsorption treatment is 100-500 m / s. 3 / h, for example, could be 100m 3 / h、200m 3 / h, 300m 3 / h, 400m 3 / h or 500m 3 / h, but not limited to the listed values, other unlisted values ​​within the range also apply.

[0042] Preferably, the temperature of the second adsorption treatment is 10-40℃, for example, it can be 10℃, 15℃, 20℃, 25℃, 30℃, 35℃ or 40℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 20-30℃.

[0043] Preferably, the volume hourly space velocity (VHSV) of the second adsorption treatment is 100-500 m / s. 3 / h, for example, could be 100m 3 / h、200m 3 / h, 300m 3 / h, 400m 3 / h or 500m 3 / h, but not limited to the listed values, other unlisted values ​​within the range also apply.

[0044] Preferably, the temperature of the reboiler in the first distillation process is 20-30°C, for example, it can be 20°C, 24°C, 25°C, 27°C, 28°C or 30°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0045] Preferably, the absolute pressure of the first distillation treatment is 0.1-1 MPa, for example, it can be 0.1 MPa, 0.3 MPa, 0.5 MPa, 0.6 MPa, 0.8 MPa or 1 MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 0.21-0.24 MPa.

[0046] Preferably, the top product ratio of the first distillation process is 0.7-0.95, for example, it can be 0.7, 0.75, 0.8, 0.85, 0.9 or 0.95, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 0.85-0.9.

[0047] Preferably, the reflux ratio of the first distillation process is 5-20, for example, it can be 5, 8, 10, 12, 15, 18 or 20, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 8-10.

[0048] Preferably, the temperature of the reboiler in the second distillation process is 20-30°C, for example, 20°C, 24°C, 25°C, 27°C, 28°C or 30°C, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0049] Preferably, the absolute pressure of the second distillation treatment is 0.05-0.8 MPa, for example, it can be 0.05 MPa, 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa or 0.8 MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 0.14-0.21 MPa.

[0050] Preferably, the bottom product ratio of the second distillation process is 0.7-0.9, for example, it can be 0.7, 0.75, 0.8, 0.85 or 0.9, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 0.8-0.9.

[0051] Preferably, the reflux ratio of the second distillation process is 5-30, for example, it can be 5, 10, 15, 20, 25 or 30, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 10-12.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] (1) The purification device system provided by the present invention has a simple structure, which can not only achieve the purification of hexafluoro-1,3-butadiene, but also ensure the yield of hexafluoro-1,3-butadiene.

[0054] (2) The purification method provided by the present invention is simple to operate. It only requires sequential acid removal treatment, first adsorption treatment, second adsorption treatment, first distillation treatment and second distillation treatment to purify hexafluorobutadiene raw material. It can also make the purity of the obtained hexafluoro-1,3-butadiene reach more than 99.99% and the yield reach more than 68%. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the purification apparatus system for hexafluoro-1,3-butadiene provided by the present invention.

[0056] Among them: 1, acid removal device; 2, first adsorption device; 3, second adsorption device; 4, first distillation device; 5, second distillation device. Detailed Implementation

[0057] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0058] To clearly illustrate the technical solution of the present invention, the composition of the hexafluorobutadiene raw material in the specific embodiments of the present invention, by mass percentage, is as follows: 45 ppm HF, 30 ppm H2O, 1200 ppm N2, 500 ppm CO, 800 ppm CO2, 650 ppm hexafluoro-2-butyne (C4F6), 80 ppm octafluoro-2-butene (C4F8), 120 ppm heptafluoro-2-butene (C4HF7), 60 ppm trifluorobromoethylene (C2BrF3), 100 ppm tetrafluorodibromoethane (C2BrF4), and the remainder is hexafluoro-1,3-butadiene.

[0059] The composition of the hexafluorobutadiene raw material is only for clearly illustrating the technical solution of the present invention and is not considered as a further limitation of the present invention.

[0060] Example 1

[0061] This embodiment provides a method such as Figure 1 The purification apparatus system for hexafluoro-1,3-butadiene shown includes an acid removal device 1, a first adsorption device 2, a second adsorption device 3, a first distillation device 4, and a second distillation device 5 connected in sequence.

[0062] The first adsorption device 2 is equipped with a first adsorbent for dehydration; the first adsorbent is anhydrous calcium sulfate.

[0063] The second adsorption device 3 is equipped with a second adsorbent for adsorbing organic and inorganic impurities; the second adsorbent is a commercially available 5A carbon molecular sieve with an average particle size of 4 mm.

[0064] The acid removal device 1 is a countercurrent absorption tower, in which acid removal packing is provided; the acid removal packing is polypropylene multifaceted hollow spheres.

[0065] The first distillation unit 4 is a packed tower, and the second distillation unit 5 is a packed tower; the packing in the first distillation unit 4 and the second distillation unit 5 are independently θ-ring bulk packing.

[0066] Example 2

[0067] This embodiment provides a method such as Figure 1 The purification apparatus system for hexafluoro-1,3-butadiene shown includes an acid removal device 1, a first adsorption device 2, a second adsorption device 3, a first distillation device 4, and a second distillation device 5 connected in sequence.

[0068] The first adsorption device 2 is equipped with a first adsorbent for dehydration; the first adsorbent is anhydrous copper sulfate.

[0069] The second adsorption device 3 is equipped with a second adsorbent for adsorbing organic and inorganic impurities; the second adsorbent is a commercially available 5A carbon molecular sieve with an average particle size of 2 mm.

[0070] The acid removal device 1 is a countercurrent absorption tower, in which acid removal packing is installed; the acid removal packing is commercially available polyvinyl chloride Pall rings.

[0071] The first distillation unit 4 is a packed tower, and the second distillation unit 5 is a packed tower; the packing in the first distillation unit 4 and the second distillation unit 5 are respectively independently structured wire mesh corrugated packing.

[0072] Example 3

[0073] This embodiment provides a method such as Figure 1 The purification apparatus system for hexafluoro-1,3-butadiene shown includes an acid removal device 1, a first adsorption device 2, a second adsorption device 3, a first distillation device 4, and a second distillation device 5 connected in sequence.

[0074] The first adsorption device 2 is equipped with a first adsorbent for dehydration; the first adsorbent is anhydrous copper sulfate.

[0075] The second adsorption device 3 is equipped with a second adsorbent for adsorbing organic and inorganic impurities; the second adsorbent is a commercially available all-silicon molecular sieve with an average particle size of 5 mm.

[0076] The acid removal device 1 is a countercurrent absorption tower, in which acid removal packing is installed; the acid removal packing is commercially available polypropylene Raschig rings.

[0077] The first distillation unit 4 is a packed tower, and the second distillation unit 5 is a packed tower; the packing in the first distillation unit 4 and the second distillation unit 5 are independently structured perforated corrugated packing.

[0078] Example 4

[0079] This embodiment provides a method such as Figure 1 The purification apparatus system for hexafluoro-1,3-butadiene shown includes an acid removal device 1, a first adsorption device 2, a second adsorption device 3, a first distillation device 4, and a second distillation device 5 connected in sequence.

[0080] The first adsorption device 2 is equipped with a first adsorbent for dehydration; the first adsorbent is anhydrous copper sulfate.

[0081] The second adsorption device 3 is equipped with a second adsorbent for adsorbing organic and inorganic impurities; the second adsorbent is commercially available activated carbon with an average particle size of 4 mm.

[0082] The acid removal device 1 is a bubbling absorption tower, in which acid removal packing is provided; the acid removal packing is a commercially available polyethylene conjugate ring.

[0083] The first distillation unit 4 is a packed tower, and the second distillation unit 5 is a packed tower; the packing in the first distillation unit 4 and the second distillation unit 5 are respectively independently structured wire mesh corrugated packing.

[0084] Application Example 1

[0085] This application example provides a purification method for the purification apparatus system provided in Application Embodiment 1, the purification method comprising the following steps:

[0086] The hexafluorobutadiene feedstock is subjected to acid removal treatment, first adsorption treatment, second adsorption treatment, first distillation treatment and second distillation treatment in sequence to complete the purification of hexafluoro-1,3-butadiene.

[0087] The absorbent used in the acid removal treatment is a 3 wt% sodium bicarbonate solution, and the temperature of the acid removal treatment is 25°C.

[0088] The first adsorption treatment was performed at a temperature of 25°C and a volume hourly space velocity of 200 m / s. 3 / h;

[0089] The second adsorption treatment was performed at a temperature of 25°C and a volume hourly space velocity of 150 m / s. 3 / h;

[0090] The reboiler temperature of the first distillation process is 25°C, the absolute pressure is 0.21 MPa, the top product ratio is 0.9, and the reflux ratio is 8.

[0091] The temperature of the bottom of the second distillation column is 25°C, the absolute pressure is 0.14 MPa, the bottom product ratio is 0.9, and the reflux ratio is 10.

[0092] Application Example 2

[0093] This application example provides a purification method for the purification apparatus system provided in Application Embodiment 1, the purification method comprising the following steps:

[0094] The hexafluorobutadiene feedstock is subjected to acid removal treatment, first adsorption treatment, second adsorption treatment, first distillation treatment and second distillation treatment in sequence to complete the purification of hexafluoro-1,3-butadiene.

[0095] The absorbent used in the acid removal treatment is a 4 wt% sodium carbonate solution, and the temperature of the acid removal treatment is 20°C.

[0096] The first adsorption treatment was performed at a temperature of 20°C and a volume hourly space velocity of 150 m / s. 3 / h;

[0097] The second adsorption treatment was performed at a temperature of 25°C and a volume hourly space velocity of 150 m / s. 3 / h;

[0098] The reboiler temperature of the first distillation process is 30°C, the absolute pressure is 0.24 MPa, the top product ratio is 0.85, and the reflux ratio is 9.

[0099] The temperature of the bottom of the second distillation column is 20°C, the absolute pressure is 0.21 MPa, the bottom product ratio is 0.8, and the reflux ratio is 11.

[0100] Application Example 3

[0101] This application example provides a purification method for the purification apparatus system provided in Application Embodiment 1, the purification method comprising the following steps:

[0102] The hexafluorobutadiene feedstock is subjected to acid removal treatment, first adsorption treatment, second adsorption treatment, first distillation treatment and second distillation treatment in sequence to complete the purification of hexafluoro-1,3-butadiene.

[0103] The absorbent used in the acid removal treatment is water, and the temperature of the acid removal treatment is 30°C.

[0104] The first adsorption treatment was performed at a temperature of 30°C and a volume hourly space velocity of 200 m / s. 3 / h;

[0105] The second adsorption treatment was performed at a temperature of 30°C and a volume hourly space velocity of 200 m / s. 3 / h;

[0106] The reboiler temperature of the first distillation process is 20°C, the absolute pressure is 0.21 MPa, the top product ratio is 0.9, and the reflux ratio is 10.

[0107] The temperature of the bottom of the second distillation column is 30°C, the absolute pressure is 0.14 MPa, the bottom product ratio is 0.85, and the reflux ratio is 12.

[0108] Application Example 4

[0109] This application example provides a purification method for the purification apparatus system provided in Application Embodiment 1, the purification method comprising the following steps:

[0110] The hexafluorobutadiene feedstock is subjected to acid removal treatment, first adsorption treatment, second adsorption treatment, first distillation treatment and second distillation treatment in sequence to complete the purification of hexafluoro-1,3-butadiene.

[0111] The absorbent used in the acid removal treatment is water, and the temperature of the acid removal treatment is 20°C.

[0112] The first adsorption treatment was performed at a temperature of 20°C and a volume hourly space velocity of 200 m / s. 3 / h;

[0113] The second adsorption treatment was performed at a temperature of 20°C and a volume hourly space velocity of 200 m / s. 3 / h;

[0114] The reboiler temperature of the first distillation process is 25°C, the absolute pressure is 0.21 MPa, the top product ratio is 0.85, and the reflux ratio is 8.

[0115] The temperature of the bottom of the second distillation column is 25°C, the absolute pressure is 0.14 MPa, the bottom product ratio is 0.9, and the reflux ratio is 10.

[0116] Application Example 5

[0117] This application example provides a purification method for the purification apparatus system provided in Application Embodiment 1, the purification method comprising the following steps:

[0118] The hexafluorobutadiene feedstock is subjected to acid removal treatment, first adsorption treatment, second adsorption treatment, first distillation treatment and second distillation treatment in sequence to complete the purification of hexafluoro-1,3-butadiene.

[0119] The absorbent used in the acid removal treatment is a 3 wt% sodium bicarbonate solution, and the temperature of the acid removal treatment is 10°C.

[0120] The temperature of the first adsorption treatment was 10°C, and the volume hourly space velocity was 100 m / s. 3 / h;

[0121] The second adsorption treatment was performed at a temperature of 10°C and a volume hourly space velocity of 100 m / s. 3 / h;

[0122] The reboiler temperature of the first distillation process is 20°C, the absolute pressure is 0.1 MPa, the top product ratio is 0.7, and the reflux ratio is 20.

[0123] The temperature of the bottom of the second distillation column is 20°C, the absolute pressure is 0.05 MPa, the bottom product ratio is 0.7, and the reflux ratio is 30.

[0124] Application Example 6

[0125] This application example provides a purification method for the purification apparatus system provided in Application Embodiment 1, the purification method comprising the following steps:

[0126] The hexafluorobutadiene feedstock is subjected to acid removal treatment, first adsorption treatment, second adsorption treatment, first distillation treatment and second distillation treatment in sequence to complete the purification of hexafluoro-1,3-butadiene.

[0127] The absorbent used in the acid removal treatment is a 3 wt% sodium bicarbonate solution, and the temperature of the acid removal treatment is 40°C.

[0128] The first adsorption treatment was performed at a temperature of 40°C and a volume hourly space velocity of 500 m / s. 3 / h;

[0129] The second adsorption treatment was performed at a temperature of 40°C and a volume hourly space velocity of 500 m / s. 3 / h;

[0130] The temperature of the bottom of the first distillation column is 30°C, the absolute pressure is 1 MPa, the top product ratio is 0.95, and the reflux ratio is 5.

[0131] The temperature of the bottom of the second distillation column is 30°C, the absolute pressure is 0.8 MPa, the bottom product ratio is 0.9, and the reflux ratio is 5.

[0132] Application Example 7

[0133] This application example provides a purification method, which is the same as that in application example 1, except that the purification method is carried out in the purification apparatus system provided in example 2.

[0134] Application Example 8

[0135] This application example provides a purification method, which is the same as that in application example 1, except that the purification method is carried out in the purification apparatus system provided in example 3.

[0136] Application Example 9

[0137] This application example provides a purification method, which is the same as that in application example 1, except that the purification method is carried out in the purification apparatus system provided in example 4.

[0138] The purity and yield of hexafluoro-1,3-butadiene obtained in corresponding cases 1-9 were tested, and the results are shown in Table 1. OFC in Table 1 represents the total content of organic impurities in the obtained hexafluoro-1,3-butadiene.

[0139] Table 1

[0140]

[0141] In summary, the purification apparatus system provided by this invention has a simple structure, which can not only purify hexafluoro-1,3-butadiene, but also ensure the yield of hexafluoro-1,3-butadiene. The purification method provided by this invention is simple to operate, requiring only sequential acid removal treatment, first adsorption treatment, second adsorption treatment, first distillation treatment, and second distillation treatment to purify the hexafluorobutadiene raw material, and can achieve a purity of over 99.99% and a yield of over 68% for the obtained hexafluoro-1,3-butadiene.

[0142] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for purifying hexafluoro-1,3-butadiene, characterized in that, Includes the following steps: The hexafluorobutadiene feedstock is subjected to acid removal treatment, first adsorption treatment, second adsorption treatment, first distillation treatment and second distillation treatment in sequence to complete the purification of hexafluoro-1,3-butadiene. The purification method is carried out in a purification device system for hexafluoro-1,3-butadiene; the purification device system includes an acid removal device, a first adsorption device, a second adsorption device, a first distillation device, and a second distillation device connected in sequence. The first adsorption device is equipped with a first adsorbent for dehydration; The second adsorption device is equipped with a second adsorbent for adsorbing organic and inorganic impurities; the second adsorbent includes 5A carbon molecular sieve and / or activated carbon; the average particle size of the second adsorbent is 2-5 mm; The first distillation unit is used to remove heavy components; the second distillation unit is used to remove light components.

2. The purification method according to claim 1, characterized in that, The acid removal device includes a countercurrent absorption device or a bubbling absorption device.

3. The purification method according to claim 1, characterized in that, The acid removal device is equipped with acid removal packing material.

4. The purification method according to claim 3, characterized in that, The acid removal packing includes any one or a combination of at least two of the following: multifaceted hollow spheres, Pall rings, Raschig rings, rectangular saddle rings, conjugate rings, or Heil rings.

5. The purification method according to claim 3, characterized in that, The acid-removing filler material includes any one of polyethylene, polypropylene, polyvinyl chloride, or polytetrafluoroethylene.

6. The purification method according to claim 1, characterized in that, The first adsorbent includes any one or a combination of at least two of anhydrous calcium sulfate, fine-porous silica gel, anhydrous calcium chloride, or anhydrous copper sulfate.

7. The purification method according to claim 1, characterized in that, The first distillation unit is a packed tower.

8. The purification method according to claim 1, characterized in that, The second distillation unit is a packed tower.

9. The purification method according to claim 1, characterized in that, The absorbent used in the acid removal treatment includes any one or a combination of at least two of the following: water, sodium bicarbonate solution, or sodium carbonate solution.

10. The purification method according to claim 9, characterized in that, The concentration of the sodium bicarbonate solution is 2-4 wt%.

11. The purification method according to claim 9, characterized in that, The concentration of the sodium carbonate solution is 2-5 wt%.

12. The purification method according to claim 1, characterized in that, The temperature for the acid removal treatment is 10-40℃.

13. The purification method according to claim 12, characterized in that, The temperature for the acid removal treatment is 20-30℃.

14. The purification method according to claim 1, characterized in that, The temperature of the first adsorption treatment is 10-40℃.

15. The purification method according to claim 14, characterized in that, The temperature of the first adsorption treatment is 20-30℃.

16. The purification method according to claim 1, characterized in that, The volume hourly space velocity (VHSV) of the first adsorption treatment is 100-500 m. 3 / h.

17. The purification method according to claim 16, characterized in that, The volume hourly space velocity (VHSV) of the first adsorption treatment is 150-200 m. 3 / h.

18. The purification method according to claim 1, characterized in that, The temperature for the second adsorption treatment is 10-40℃.

19. The purification method according to claim 18, characterized in that, The temperature for the second adsorption treatment is 20-30℃.

20. The purification method according to claim 1, characterized in that, The volume hourly space velocity (VHSV) of the second adsorption treatment is 100-500 m / s. 3 / h.

21. The purification method according to claim 20, characterized in that, The volume hourly space velocity (VHSV) of the second adsorption treatment is 150-200 m / s. 3 / h.

22. The purification method according to claim 1, characterized in that, The temperature of the bottom of the first distillation treatment column is 20-30℃.

23. The purification method according to claim 1, characterized in that, The absolute pressure of the first distillation process is 0.1-1 MPa.

24. The purification method according to claim 23, characterized in that, The absolute pressure of the first distillation process is 0.21-0.24 MPa.

25. The purification method according to claim 1, characterized in that, The top product ratio of the first distillation process is 0.7-0.

95.

26. The purification method according to claim 25, characterized in that, The top product ratio of the first distillation process is 0.85-0.

9.

27. The purification method according to claim 1, characterized in that, The reflux ratio of the first distillation process is 5-20.

28. The purification method according to claim 27, characterized in that, The reflux ratio of the first distillation process is 8-10.

29. The purification method according to claim 1, characterized in that, The temperature of the bottom column in the second distillation process is 20-30℃.

30. The purification method according to claim 1, characterized in that, The absolute pressure of the second distillation process is 0.05-0.8 MPa.

31. The purification method according to claim 30, characterized in that, The absolute pressure of the second distillation process is 0.14-0.21 MPa.

32. The purification method according to claim 1, characterized in that, The bottom product ratio of the second distillation treatment is 0.7-0.

9.

33. The purification method according to claim 32, characterized in that, The bottom product ratio of the second distillation treatment is 0.8-0.

9.

34. The purification method according to claim 1, characterized in that, The reflux ratio for the second distillation process is 5-30.

35. The purification method according to claim 34, characterized in that, The reflux ratio for the second distillation process is 10-12.

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