Apparatus and method for purifying phosphorus trifluoride

Abstract

A phosphorus trifluoride (PF3) using a continuous distillation column, according to the present invention, utilizes: a first distillation column in which a mixture containing at least a portion of PF3 is distilled to discharge PF3, HCl, HF, PCl3, and acetonitrile from the column bottom and discharge a mixture of PF3, HCl, and N2 from the column top; a second distillation column in which the mixture of PF3, HCl, and N2 is distilled to discharge PF3 and HCl from the column bottom and discharge the mixture of PF3 and N2 from the top column; and a third distillation column in which the mixture of PF3 and N2 is distilled to discharge PF3 from the column bottom and discharge N2 from the column top.

Description

Phosphorus trifluoride purification apparatus and purification method

[0001] The present invention relates to a phosphorus trifluoride purification apparatus and a purification method.

[0002] Phosphorus trifluoride is an industrial gas that can be used, for example, as a specialty gas. Specialty gases possess a purity higher than that required for general industrial applications and are intended for specific uses. Specialty gases may include electronic and semiconductor gases, standard gases, rare gases, and mixed gases.

[0003] Specifically, phosphorus trifluoride can be used as a specialty gas for semiconductors, such as for semiconductor manufacturing and research, and for TFT-LCD manufacturing. For example, phosphorus trifluoride can be used in etching or cleaning processes during semiconductor fabrication. In this case, the purity of phosphorus trifluoride can affect the degree of etching and pattern formation of the semiconductor wafer. Therefore, to be used as a specialty gas for semiconductors, a higher purity is required than that required for general industrial gases.

[0004] A conventional method for producing phosphorus trifluoride involves reacting hydrogen fluoride with a phosphorus compound. Hydrogen fluoride, the raw material, requires special caution during handling because its strong hydrogen bonding can cause violent exothermic reactions or explosions upon contact with moisture in the air. Furthermore, not only hydrogen fluoride but also its byproducts are highly acidic substances, posing significant limitations to their application in industrial settings.

[0005] Therefore, efforts are required to find safe raw materials that can replace hydrogen fluoride in the production of phosphorus trifluoride. However, in conventional technology, it is not easy to optimize processes such as chemical reaction, purification, mixing, and extraction to ensure process safety by changing the types of reactants, while simultaneously increasing the purity of phosphorus trifluoride gas.

[0006] One aspect of the present invention for solving the aforementioned problem is to provide a phosphorus trifluoride purification apparatus and a purification method that can purify and recover high-purity phosphorus trifluoride by increasing the separation efficiency of phosphorus trifluoride (PF3) using a distillation apparatus utilizing a continuous distillation column.

[0007] The technical problems intended to be solved in this document are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this invention belongs from the description below.

[0008] To achieve the above objective, a phosphorus trifluoride (crude PF3) purification apparatus using a continuous distillation column according to one embodiment of the present invention may include: a first distillation column that distills a mixture containing at least a portion of PF3 to discharge PF3, HCl, HF, PCl3, and acetonitrile from the bottom of the column and discharges a mixture of PF3, HCl, and N2 from the top of the column; a second distillation column that distills the mixture of PF3, HCl, and N2 discharged from the first distillation column to discharge PF3 and HCl from the bottom of the column and discharges a mixture of PF3 and N2 from the top of the column; and a third distillation column that distills the mixture of PF3 and N2 discharged from the second distillation column to discharge PF3 from the bottom of the column and discharge N2 from the top of the column.

[0009] According to one embodiment of the present invention, the first distillation column may include a first condenser at a temperature of -85°C to -70°C and a first reboiler at a temperature of -55°C to -40°C.

[0010] According to one embodiment of the present invention, the second distillation column may include a second condenser at a temperature of -85°C to -75°C and a second reboiler at a temperature of -82°C to -70°C.

[0011] According to one embodiment of the present invention, the third distillation column may include a third condenser at a temperature of -106°C to -96°C and a third reboiler at a temperature of -82°C to -70°C.

[0012] According to one embodiment of the present invention, PF3 discharged from the first distillation column and PF3 discharged from the second distillation column can be reintroduced into the first distillation column.

[0013] According to one embodiment of the present invention, some of the mixture of PF3, HCl, and N2 discharged from the top of the first distillation column may be transferred to the second distillation column, and some may be reintroduced to the first distillation column.

[0014] According to one embodiment of the present invention, some of the mixture of PF3 and N2 discharged from the top of the second distillation column may be transferred to a third distillation column, and some may be reintroduced to the second distillation column.

[0015] According to one embodiment of the present invention, some of the N2 discharged from the top of the third distillation column may be discharged, and some may be reintroduced into the third distillation column.

[0016] A method for purifying high-purity phosphorus trifluoride (PF3) according to one embodiment of the present invention may include: a first distillation step in which a mixture containing at least a portion of PF3 is distilled in a first distillation column to discharge PF3, HCl, HF, PCl3, and acetonitrile from the bottom of the column and a mixture of PF3, HCl, and N2 is discharged from the top of the column; a second distillation step in which the mixture of PF3, HCl, and N2 discharged from the first distillation column is transferred into a second distillation column and the transferred mixture of PF3, HCl, and N2 is distilled to discharge PF3 and HCl from the bottom of the column and a mixture of PF3 and N2 is discharged from the top of the column; and a third distillation step in which the mixture of PF3 and N2 discharged from the second distillation column is transferred into a third distillation column and the transferred mixture of PF3 and N2 is distilled to discharge PF3 from the bottom of the column and N2 from the top of the column.

[0017] According to one embodiment of the present invention, the first distillation step may be performed in a first distillation column comprising a first condenser at a temperature of -85°C to -70°C and a first reboiler at a temperature of -55°C to -40°C.

[0018] According to one embodiment of the present invention, the second distillation step may be performed in a second distillation column comprising a second condenser at a temperature of -85°C to -75°C and a second reboiler at a temperature of -82°C to -70°C.

[0019] According to one embodiment of the present invention, the third distillation step may be performed in a third distillation column comprising a third condenser at a temperature of -106°C to -96°C and a third reboiler at a temperature of -82°C to -70°C.

[0020] According to one embodiment of the present invention, PF3 discharged from the first distillation step and PF3 discharged from the second distillation step can be reintroduced into the first distillation tower to perform the first distillation step again.

[0021] In the first distillation step according to one embodiment of the present invention, some of the mixture of PF3, HCl, and N2 discharged from the top of the first distillation column may be transferred to the second distillation column, and some may be reintroduced to the first distillation column.

[0022] In the second distillation step according to one embodiment of the present invention, some of the mixture of PF3 and N2 discharged from the top of the second distillation column may be transferred to a third distillation column, and some may be reintroduced to the second distillation column.

[0023] In the third distillation step according to one embodiment of the present invention, some of the N2 discharged from the top of the third distillation column may be discharged, and some may be reintroduced into the third distillation column.

[0024] The purity of phosphorus trifluoride separated through the third distillation step according to one embodiment of the present invention may be 99.99% or higher.

[0025] According to the present invention, a PF3 purification apparatus and a purification method can be provided that can purify and recover high-purity phosphorus trifluoride by increasing the separation efficiency of phosphorus trifluoride (PF3) using a distillation apparatus utilizing a continuous distillation column.

[0026] The effects obtainable from the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present invention belongs from the description below.

[0027] FIG. 1 is a schematic diagram illustrating the configuration of a phosphorus trifluoride (PF3) purification apparatus using a continuous distillation column according to one embodiment of the present invention.

[0028] Preferred embodiments of the present invention will be described below with reference to the attached drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

[0029] In drawings, the shapes and sizes of elements may be exaggerated for clearer explanation.

[0030] Throughout the specification, the same reference numerals refer to the same components. This specification does not describe all elements of the embodiments, and general content in the art to which the invention pertains or content that overlaps between embodiments is omitted. According to the embodiments of this specification, it is possible for a plurality of 'parts, modules, components, blocks' to be implemented as a single component, or for a single 'part, module, component, block' to include a plurality of components.

[0031] Throughout the specification, when a part is described as being "connected" to another part, this includes not only cases where they are directly connected but also cases where they are indirectly connected, and indirect connections include connections made via a wireless communication network.

[0032] Furthermore, when it is stated that a part "includes" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0033] Throughout the specification, when it is stated that a component is located "on" another component, this includes not only cases where a component is in contact with another component, but also cases where another component exists between the two components.

[0034] The terms first, second, etc. are used to distinguish one component from another, and the components are not limited by the aforementioned terms.

[0035] Singular expressions include plural expressions unless there is an obvious exception in the context.

[0036] In each step, identification codes are used for convenience of explanation and do not describe the order of the steps; the steps may be performed differently from the specified order unless a specific order is clearly indicated in the context.

[0037] As used in this specification, the term 'top of the tower' means the upper surface of the distillation tower, and the term 'bottom of the tower' means the lower surface of the distillation tower.

[0038] As used in this specification, the term "condenser" refers to a device installed in the path of a piping system separately from the main body of a distillation column, and may refer to a cooling device for cooling a substance discharged from the main body by means such as contacting it with cooling water from the outside. Additionally, the term "reboiler" may refer to, for example, a heating device installed outside the distillation column, and may refer to an evaporation device for reheating and evaporating a product rich in high-boiling-point components extracted from the bottom of the distillation column.

[0039] The continuous distillation column included in the phosphorus trifluoride purification apparatus according to the present invention is a device for separating high-purity phosphorus trifluoride from crude phosphorus trifluoride, and is characterized by including three distillation columns.

[0040] In addition, the phosphorus trifluoride purification apparatus according to the present invention has a condenser installed outside the top of each of the first distillation column, the second distillation column, and the third distillation column, and a reboiler installed outside the bottom of each of the first distillation column, the second distillation column, and the third distillation column.

[0041] A phosphorus trifluoride (PF3) purification apparatus using a continuous distillation column according to a preferred embodiment of the present invention will be described in detail below with reference to the attached drawings.

[0042] FIG. 1 is a schematic diagram illustrating the configuration of a phosphorus trifluoride (PF3) purification apparatus using a continuous distillation column according to a preferred embodiment of the present invention.

[0043] As illustrated in FIG. 1, the phosphorus trifluoride (PF3) purification apparatus according to the present invention (hereinafter referred to as the ‘apparatus’) comprises a first distillation tower (20) connected to a phosphorus trifluoride manufacturing apparatus (10), a second distillation tower (30) connected to the first distillation tower (20), and a third distillation tower (40) connected to the second distillation tower (30).

[0044] The first distillation column (20) distills a mixture containing at least some PF3, discharging PF3, HCl, HF, PCl3, and acetonitrile from the bottom of the column and a mixture of PF3, HCl, and N2 from the top of the column.

[0045] The mixture containing at least some of the above-mentioned PF3 can be applied to the purification apparatus without limitation as long as it is a mixture containing at least some of the PF3 generated during the phosphorus trifluoride manufacturing process, for example, it may be crude phosphorus trifluoride (crude PF3) obtained after the manufacture of phosphorus trifluoride.

[0046] The phosphorus trifluoride above may be produced in a phosphorus trifluoride production device (10) connected to a first distillation column, and the phosphorus trifluoride production device (10) may include a reaction space for PCl3, NaF, acetonitrile, and a catalyst to react. The reaction space may include a spiral screw reactor.

[0047] The crude trifluoride produced in the above-described phosphorus trifluoride manufacturing device (10) may further include a compressor (not shown) for pressurizing the crude trifluoride before it is introduced into the first distillation tower (20). Additionally, a storage tank (not shown) for storing the crude trifluoride pressurized by the compressor may be included between the phosphorus trifluoride manufacturing device (10) and the first distillation tower (20). The compressor may be provided in the connection between the phosphorus trifluoride manufacturing device (10) and the first distillation tower (20), or it may be provided within the storage tank for storing the crude trifluoride.

[0048] In the first distillation column (20) above, a mixture containing at least some PF3, preferably the crude phosphorus trifluoride, is distilled to discharge PF3, HCl, HF, PCl3, and acetonitrile from the bottom of the column, and a mixture of PF3, HCl, and N2 from the top of the column.

[0049] A first condenser (21) is installed outside the top of the first distillation tower (20), and a first reboiler (22) is installed outside the bottom of the tower. The first condenser and the first reboiler can be installed in various shapes, not just the shape shown in FIG. 1.

[0050] The temperature of the first condenser (21) may be -85°C to -70°C, and the temperature of the first reboiler (22) may be -55°C to -40°C.

[0051] When a mixture containing at least some PF3, preferably crude phosphorus trifluoride, is introduced into the first distillation column (20), the vapor evaporated in the first reboiler (22) rises toward the upper direction of the distillation column, and the liquid condensed in the first condenser (21) is refluxed and flows toward the lower direction of the distillation column. When the vapor and the liquid come into contact inside the first distillation column (20), the vapor condenses and the liquid evaporates, and the vapor is condensed by the first condenser (21), some of which is transferred to the second distillation column (30), and some is reintroduced back into the first distillation column (20). In addition, some of the components discharged from the lower part of the first distillation column (20) are stored in the first storage tank (23) connected to the first reboiler (22), and some can be evaporated again in the first reboiler (22) and sent to the bottom of the first distillation column (20). In particular, the PF3 discharged from the top of the tower can be transferred to the first distillation tower (20) and undergo a purification process using a continuous distillation tower again.

[0052] In the second distillation tower (30) and third distillation tower (40) described later, the components introduced can also be separated and discharged using the same principle as above.

[0053] The second distillation column (30) is connected to the first distillation column (20) and distills the mixture of PF3, HCl, and N2 discharged from the top of the first distillation column (20), discharging PF3 and HCl from the bottom of the column and discharging the mixture of PF3 and N2 from the top of the column.

[0054] A second condenser (31) is installed outside the top of the second distillation tower (30), and a second reboiler (32) is installed outside the bottom of the tower. The temperature of the second condenser (31) may be -85°C to -75°C, and the temperature of the second reboiler (32) may be -82°C to -70°C.

[0055] In the second distillation tower (30) above, a mixture of PF3, HCl, and N2 can be distilled and discharged using the same principle as the first distillation tower (20) described above, and a detailed explanation is omitted here.

[0056] A portion of the mixture of PF3 and N2 discharged from the top of the second distillation column (30) is fed into the third distillation column (40), and a portion is reintroduced into the second distillation column (30). Additionally, a portion of the PF3 and HCl discharged from the bottom of the second distillation column (30) is stored in the second storage tank (33) connected to the second reboiler (32), and a portion can be sent back to the bottom of the second distillation column (30). In particular, the PF3 discharged from the bottom can be transferred to the first distillation column (20) and undergo a purification process using a continuous distillation column.

[0057] The third distillation tower (40) is connected to the second distillation tower (30) and separates the mixture of PF3 and N2 discharged from the top of the second distillation tower (30) by distillation.

[0058] A third condenser (41) is installed outside the top of the third distillation tower (40), and a third reboiler (42) is installed outside the bottom of the tower. The temperature of the third condenser (41) may be -106°C to -96°C, and the temperature of the third reboiler (42) may be -82°C to -70°C.

[0059] In the above third distillation tower (40), the mixture of PF3 and N2 can be distilled and discharged using the same principle as the above first distillation tower (20), and a detailed explanation is omitted here.

[0060] Some of the N2 discharged from the top of the third distillation tower (40) is reintroduced into the third distillation tower (40). Additionally, some of the PF3 discharged from the bottom of the third distillation tower (40) is stored in the third storage tank (43) connected to the third reboiler (42), and some can be sent back to the bottom of the third distillation tower (40).

[0061] As described above, phosphorus trifluoride (PF3) separated by continuous distillation through the first distillation column, the second distillation column, and the third distillation column can have high purity, that is, a purity of 99.99% or higher. In other words, according to the present invention, phosphorus trifluoride of high purity can be purified using a phosphorus trifluoride purification apparatus utilizing three continuous distillation columns.

[0062] Next, a method for purifying phosphorus trifluoride (PF3) using the phosphorus trifluoride purification apparatus utilizing the continuous distillation column of the present invention will be described.

[0063] The method for purifying phosphorus trifluoride using the above-described continuous distillation column may include: a first distillation step in which a mixture containing at least a portion of PF3 is distilled in a first distillation column to discharge PF3, HCl, HF, PCl3, and acetonitrile from the bottom of the column and a mixture of PF3, HCl, and N2 is discharged from the top of the column; a second distillation step in which the mixture of PF3, HCl, and N2 discharged from the first distillation column is transferred into a second distillation column and the transferred mixture of PF3, HCl, and N2 is distilled to discharge PF3 and HCl from the bottom of the column and a mixture of PF3 and N2 from the top of the column; and a third distillation step in which the mixture of PF3 and N2 discharged from the second distillation column is transferred into a third distillation column and the transferred mixture of PF3 and N2 is distilled to discharge PF3 from the bottom of the column and N2 from the top of the column.

[0064] Each step is explained in detail below.

[0065] First, in the first distillation step, a mixture containing at least some PF3 is distilled in the first distillation column, and PF3, HCl, HF, PCl3, and acetonitrile are discharged from the bottom of the column, and a mixture of PF3, HCl, and N2 is discharged from the top of the column.

[0066] The mixture containing at least some of the above-mentioned PF3 can be applied to the purification apparatus without limitation as long as it is a mixture containing at least some of the PF3 generated during the phosphorus trifluoride manufacturing process, for example, it may be crude phosphorus trifluoride (crude PF3) obtained after the manufacture of phosphorus trifluoride.

[0067] The above crude trifluoride may be manufactured using a trifluoride manufacturing device (10).

[0068] Specifically, the crude phosphorus trifluoride may include the steps of introducing NaF and a catalyst into a screw reactor and introducing PCl3 and acetonitrile into the screw reactor to obtain crude phosphorus trifluoride. Additionally, after the step of introducing NaF, the process may be carried out by vacuum purging the inside of the screw reactor with an inert gas.

[0069] The above phosphorus trifluoride manufacturing device (10) may be a single device, or two or more manufacturing devices may be connected in parallel or in series.

[0070] The crude phosphorus trifluoride produced in the above phosphorus trifluoride manufacturing device (10) may contain, in addition to phosphorus trifluoride, about 10% by-products such as HCl, HF, unreacted phosphorus chloride compounds, solvents, etc.

[0071] Therefore, to separate pure phosphorus trifluoride from the crude phosphorus trifluoride produced above, it can be purified into high-purity phosphorus trifluoride using a phosphorus trifluoride purification device utilizing three continuous distillation columns.

[0072] The crude phosphorus trifluoride produced in the above-mentioned phosphorus trifluoride manufacturing device (10) is introduced into the first distillation tower (20), and then distilled within the first distillation tower (20) to discharge PF3, HCl, HF, PCl3, and acetonitrile from the bottom of the tower, and a mixture of PF3, HCl, and N2 from the top of the tower.

[0073] The temperature of the first condenser (21) installed outside the top of the first distillation tower (20) may be -85°C to -70°C, and the temperature of the first reboiler (22) installed outside the bottom of the tower may be -55°C to -40°C.

[0074] Some of the mixture of PF3, HCl, and N2 separated from the top of the first distillation column (20) is transferred to the second distillation column (30), and some is reintroduced to the first distillation column (20) to undergo the first distillation step again. Additionally, some of the PF3, HCl, HF, PCl3, and acetonitrile separated from the bottom of the first distillation column (20) are stored in the first storage tank (23) connected to the first reboiler (22) of the first distillation column (20), and some can be evaporated again in the first reboiler (22) and sent to the bottom of the first distillation column (20). In particular, the PF3 discharged from the bottom can be transferred to the first distillation column (20) to perform a purification process using a continuous distillation column again.

[0075] Next, the mixture of PF3, HCl, and N2 discharged from the top of the first distillation tower (20) is introduced into the second distillation tower (30) and distilled to discharge PF3 and HCl from the bottom of the tower and the mixture of PF3 and N2 from the top of the tower.

[0076] The temperature of the second condenser (31) installed outside the top of the second distillation tower (30) may be -85°C to -75°C, and the temperature of the second reboiler (32) installed outside the bottom of the tower may be -82°C to -70°C.

[0077] A portion of the mixture of PF3 and N2 separated from the top of the second distillation column (30) is transferred to the third distillation column (40), and a portion is reintroduced to the second distillation column (30) to undergo the second distillation step again. Additionally, some of the PF3 and HCl separated from the bottom of the second distillation column (30) is stored in a second storage tank (33) connected to the second reboiler (32) of the second distillation column (30), and a portion can be evaporated again in the second reboiler (32) and sent to the bottom of the second distillation column (30). In particular, the PF3 discharged from the bottom of the column can be transferred to the first distillation column (20) to perform a purification process using a continuous distillation column again.

[0078] Next, the mixture of PF3 and N2 discharged from the top of the second distillation tower (30) is introduced into the third distillation tower (40) and distilled so that PF3 is discharged from the bottom of the tower and N2 is discharged from the top of the tower.

[0079] The temperature of the third condenser (41) installed outside the top of the third distillation tower (40) may be -106°C to -96°C, and the temperature of the third reboiler (42) installed outside the bottom of the tower may be -82°C to -70°C.

[0080] Some of the N2 discharged from the top of the third distillation tower (40) can be reintroduced into the third distillation tower (40). Additionally, some of the PF3 discharged from the bottom of the third distillation tower (40) is stored in the third storage tank (43) connected to the third reboiler (42), and some can be sent back to the bottom of the third distillation tower (40).

[0081] As described above, phosphorus trifluoride (PF3) separated from the bottom of the third distillation column (40) through three consecutive distillation columns according to the present invention may have a purity of 99.99% or higher.

[0082] The present invention will be explained in more detail below through the following examples. However, the following examples are merely illustrative of the present invention, and the scope of the present invention is not limited thereto.

[0083] Example 1

[0084] Phosphorus trifluoride (PF3) was purified using a phosphorus trifluoride purification apparatus using three continuous distillation columns as shown in Fig. 1.

[0085] After introducing NaF, acetonitrile, and Sb2O3 catalyst into the screw reactor of a phosphorus trifluoride manufacturing apparatus in a weight ratio of 9.2:1:0.003, PCl3 was introduced in an amount equal to 1 / 3 of the NaF equivalent ratio (molar ratio) and reacted to produce crude PF3.

[0086] The crude PF3 prepared above was fed into a first distillation column in which a first condenser installed outside the top of the column was controlled to -78°C and a first reboiler installed outside the bottom of the column was controlled to -47°C, and then distilled to separate a mixture of PF3, HCl, and N2 from the top of the column, and separated PF3, HCl, HF, PCl3, and acetonitrile from the bottom of the column.

[0087] Next, the mixture of PF3, HCl, and N2 separated from the top of the first distillation column was fed into a second distillation column in which a second condenser installed outside the top of the column was controlled to -80°C and a second reboiler installed outside the bottom of the column was controlled to -76°C, and then distilled to separate PF3 and HCl from the bottom of the column and the mixture of PF3 and N2 from the top of the column.

[0088] Next, the mixture of PF3 and N2 separated from the top of the second distillation column was fed into a third distillation column in which a third condenser installed outside the top of the column was controlled to -101°C and a third reboiler installed outside the bottom of the column was controlled to -78°C, and then distilled to separate PF3 from the bottom of the column and N2 from the top of the column.

[0089] As described above, PF3 with a purity of 99.99% was separated from the bottom of the third distillation column.

[0090] The components obtained from the crude phosphorus trifluoride produced from the above phosphorus trifluoride production apparatus, the top and bottom of the first distillation column, the top and bottom of the second distillation column, and the top and bottom of the third distillation column were analyzed by mass spectrum and are shown in Table 1 below.

[0091] Classification Phosphorus Trifluoride Distillation 1st Distillation 2nd Distillation 3rd Distillation 3rd Column Top Bottom Top Bottom Top Bottom Temperature (°C) 25-78-47-80-76-101-78 Pressure (bar.g) 3.03.03.02.72.72.42.4 Components (%) PCl 31.73200.000026.69940.00000.00000.00000.0000 Acetonitrile 0.92280.000014.22560.00000.00000.0000.0000HF 0.45910.00497.07780.00000.00000.00000.0000 HCl1.85020.106926.97970.00541.04990.00000.0063PF389.471893.938425.01759 3.436698.950156.238899.9937N25.56415.94980.00006.55810.000043.76120.0000

[0092] As shown in Table 1 above, it was found that according to the present invention, impurities are sequentially removed from crude phosphorus trifluoride through continuous distillation using three continuous distillation columns, a first distillation column, a second distillation column, and a third distillation column, thereby enabling the purification of phosphorus trifluoride to a high purity of 99.99%.

[0093] Comparative Example 1

[0094] For Comparative Example 1, crude PF3 was used, which was not subjected to a separate purification process after the preparation of phosphorus trifluoride in Example 1 above.

[0095] The purity of the phosphorus trifluoride finally separated from Example 1 and Comparative Example 1 was analyzed by mass spectrum, and the results are shown in Table 2 below.

[0096] Classification Purity (%) Example 199.99 Comparative Example 189.47

[0097] As shown in Table 2 above, in the case of Example 1, which was sequentially distilled and separated using three continuous distillation columns according to the present invention, it was confirmed that phosphorus trifluoride could be purified to a high purity of 99.99% compared to Comparative Example 1, which did not have a separate purification process through continuous distillation columns. Although embodiments of the invention disclosed above have been illustrated and described, the disclosed invention is not limited to the specific embodiments described above, and various modifications may be made by those skilled in the art to which the disclosed invention belongs without departing from the gist of the claims.

Claims

A first distillation column that distills a mixture containing at least a portion of PF3, discharging PF3, HCl, HF, PCl3, and acetonitrile from the bottom of the column and discharging a mixture of PF3, HCl, and N2 from the top of the column; A second distillation column that distills the mixture of PF3, HCl, and N2 discharged from the first distillation column above, discharging PF3 and HCl from the bottom of the column and discharging the mixture of PF3 and N2 from the top of the column; and Phosphorus trifluoride (PF3) purification apparatus comprising: a third distillation column that distills a mixture of PF3 and N2 discharged from the second distillation column above, discharging PF3 from the bottom of the column and N2 from the top of the column. In paragraph 1, Phosphorus trifluoride (PF3) purification apparatus, wherein the first distillation column comprises a first condenser at a temperature of -85°C to -70°C and a first reboiler at a temperature of -55°C to -40°C. In paragraph 1, Phosphorus trifluoride (PF3) purification apparatus, wherein the second distillation column comprises a second condenser at a temperature of -85°C to -75°C and a second reboiler at a temperature of -82°C to -70°C. In paragraph 1, Phosphorus trifluoride (PF3) purification apparatus, wherein the above-mentioned third distillation column includes a third condenser at a temperature of -106°C to -96°C and a third reboiler at a temperature of -82°C to -70°C. In paragraph 1, Phosphorus trifluoride (PF3) purification apparatus in which PF3 discharged from the first distillation tower and PF3 discharged from the second distillation tower are reintroduced into the first distillation tower. In paragraph 1, Phosphorus trifluoride (PF3) purification apparatus, wherein a portion of the mixture of PF3, HCl, and N2 discharged from the top of the first distillation column is transferred to a second distillation column, and a portion is reintroduced to the first distillation column. In paragraph 1, Phosphorus trifluoride (PF3) purification apparatus, wherein a portion of the mixture of PF3 and N2 discharged from the top of the second distillation column is transferred to a third distillation column, and a portion is reintroduced to the second distillation column. In paragraph 1, Phosphorus trifluoride (PF3) purification apparatus in which some of the N2 discharged from the top of the third distillation tower is discharged and some is reintroduced into the third distillation tower. A first distillation step in which a mixture containing at least a portion of PF3 is distilled in a first distillation column to discharge PF3, HCl, HF, PCl3, and acetonitrile from the bottom of the column and a mixture of PF3, HCl, and N2 from the top of the column; A second distillation step of transferring the mixture of PF3, HCl, and N2 discharged from the first distillation column into a second distillation column, and distilling the transferred mixture of PF3, HCl, and N2 to discharge PF3 and HCl from the bottom of the column and discharge the mixture of PF3 and N2 from the top of the column; and A method for purifying phosphorus trifluoride (PF3), comprising: a third distillation step of transferring a mixture of PF3 and N2 discharged from the second distillation column into a third distillation column, and distilling the transferred mixture of PF3 and N2 to discharge PF3 from the bottom of the column and N2 from the top of the column. In Paragraph 9, A method for purifying phosphorus trifluoride (PF3), wherein the first distillation step is performed in a first distillation column comprising a first condenser at a temperature of -85°C to -70°C and a first reboiler at a temperature of -55°C to -40°C. In Paragraph 9, A method for purifying phosphorus trifluoride (PF3), wherein the second distillation step is performed in a second distillation column comprising a second condenser at a temperature of -85°C to -75°C and a second reboiler at a temperature of -82°C to -70°C. In Paragraph 9, A method for purifying phosphorus trifluoride (PF3), wherein the third distillation step is performed in a third distillation column comprising a third condenser at a temperature of -106°C to -96°C and a third reboiler at a temperature of -82°C to -70°C. In Paragraph 9, A method for purifying phosphorus trifluoride (PF3), wherein PF3 discharged from the first distillation step and PF3 discharged from the second distillation step are reintroduced into the first distillation column to perform the first distillation step again. In Paragraph 9, A method for purifying phosphorus trifluoride (PF3), wherein in the first distillation step, a portion of the mixture of PF3, HCl, and N2 discharged from the top of the first distillation column is transferred to a second distillation column, and a portion is reintroduced to the first distillation column. In Paragraph 9, A method for purifying phosphorus trifluoride (PF3), wherein in the second distillation step, a portion of the mixture of PF3 and N2 discharged from the top of the second distillation column is transferred to a third distillation column, and a portion is reintroduced to the second distillation column. In Paragraph 9, A method for purifying phosphorus trifluoride (PF3), wherein in the third distillation step above, some of the N2 discharged from the top of the third distillation column is discharged and some is reintroduced into the third distillation column. In Paragraph 9, A method for purifying phosphorus trifluoride (PF3) with a purity of 99.99% or higher, separated through the above third distillation step.

Images