Method for producing bromine pentafluoride

Abstract

Provided is a method for producing bromine pentafluoride, whereby it becomes possible to reduce the amount of a remaining unreacted fluorine gas and to produce bromine pentafluoride having high purity. The method for producing bromine pentafluoride comprises: a reaction step of supplying a bromine-containing compound that is at least one of a bromine gas and bromine trifluoride and a fluorine gas to a reactor (1) in such a manner that the molar ratio F / Br of fluorine atoms to bromine atoms can became 3.0 to 4.7 inclusive to perform a reaction of the bromine-containing compound with the fluorine gas, thereby producing a reaction mixture comprising bromine pentafluoride and bromine trifluoride; and a separation step of separating bromine pentafluoride and bromine trifluoride from each other in the reaction mixture.

Description

[Technical field]

[0001] The present invention relates to a method for producing bromine pentafluoride. [Background technology]

[0002] Bromine pentafluoride (BrF5) is generally produced by reacting a bromine-containing compound, which is at least one of bromine gas (Br2) and bromine trifluoride (BrF3), with fluorine gas (F2). For example, Patent Document 1 discloses a method for obtaining bromine pentafluoride by supplying bromine gas or bromine trifluoride and fluorine gas into a reactor filled with nickel fluoride (NiF2) so that the molar ratio of fluorine atoms to bromine atoms, F / Br, is 5 or more, and reacting them to obtain bromine pentafluoride. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japan Patent Publication No. 2017-197390 Summary of the Invention [Problem to be solved by the invention]

[0004] In the method for producing bromine pentafluoride disclosed in Patent Document 1, in order to produce bromine pentafluoride with a high yield, a reaction is carried out by supplying fluorine gas in a reaction system in an amount equal to or greater than a reactive equivalent. However, when an excessive amount of fluorine gas is supplied to the reaction system, a large amount of unreacted fluorine gas may remain, and therefore, it is necessary to treat the remaining fluorine gas by recovery or detoxification. An object of the present invention is to provide a method for producing bromine pentafluoride which allows production of high-purity bromine pentafluoride while leaving a small amount of unreacted fluorine gas. [Means for solving the problem]

[0005] In order to solve the above problems, one aspect of the present invention is as follows [1] to

[11] . [1] a reaction step of supplying a bromine-containing compound, which is at least one of bromine gas and bromine trifluoride, and fluorine gas into a reactor so that the molar ratio of fluorine atoms to bromine atoms, F / Br, is 3.0 or more and 4.7 or less, to react the bromine-containing compound with the fluorine gas to obtain a reaction mixture containing bromine pentafluoride and bromine trifluoride; a separation step of separating bromine pentafluoride and bromine trifluoride from the reaction mixture; A method for producing bromine pentafluoride comprising the steps of:

[0006] [2] The method for producing bromine pentafluoride according to [1], wherein in the reaction step, an inert gas is supplied into the reactor together with the bromine-containing compound and the fluorine gas to carry out the reaction, and the amount of the inert gas supplied is 50 volume % or more of the total volume of the gases consisting of the bromine-containing compound, the fluorine gas, and the inert gas. [3] The method for producing bromine pentafluoride according to [1] or [2], wherein the reaction is carried out under a pressure of 0.1 MPa or more and 0.5 MPa or less.

[0007] [4] The method for producing bromine pentafluoride according to any one of [1] to [3], wherein the reaction is carried out at a temperature of 100° C. or higher and 400° C. or lower. [5] The method for producing bromine pentafluoride according to any one of [1] to [4], wherein at least one of a metal oxide and a metal fluoride is placed in the reactor as a catalyst to carry out the reaction, and the metal is at least one of metals belonging to the third and fourth periods of the periodic table.

[0008] [6] The method for producing bromine pentafluoride according to [5], wherein the catalyst is at least one selected from Al2O3, NiF2, FeF3, CoF2, and AlF3. [7] The method for producing bromine pentafluoride according to any one of [1] to [6], wherein the reactor is a nickel bright annealing tube. [8] The method for producing bromine pentafluoride according to any one of [1] to [7], wherein the separation step comprises a cooling step of cooling the reaction mixture to separate it into a gas component containing bromine pentafluoride and a liquid / solid component containing bromine trifluoride.

[0009] [9] The method for producing bromine pentafluoride according to [8], wherein the separation step further comprises an adsorption step of contacting the gas component containing bromine pentafluoride obtained by the cooling step with an adsorbent to adsorb bromine trifluoride contained in the gas component containing bromine pentafluoride onto the adsorbent.

[10] The method for producing bromine pentafluoride according to [9], wherein the adsorbent is a fluoride of at least one metal belonging to Group 1 and Group 2 of the periodic table.

[11] The method for producing bromine pentafluoride according to [9], wherein the adsorbent is at least one selected from LiF, NaF, KF, RbF, CsF, MgF2, and CaF2. Effect of the Invention

[0010] According to the method for producing bromine pentafluoride of the present invention, the amount of remaining unreacted fluorine gas is small, and it is possible to produce high-purity bromine pentafluoride. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a bromine pentafluoride production apparatus illustrating a method for producing bromine pentafluoride according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing a modified example of the bromine pentafluoride manufacturing apparatus of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An embodiment of the present invention will be described. Note that this embodiment shows an example of the present invention, and the present invention is not limited to this embodiment. In addition, various changes or improvements can be added to this embodiment, and forms with such changes or improvements can also be included in the present invention. For example, the materials, dimensions, etc. exemplified in this embodiment are only examples, and the present invention is not limited thereto, and can be appropriately changed and implemented within the scope in which the effects of the present invention are achieved.

[0013] The method for producing bromine pentafluoride according to the present embodiment includes a reaction step and a separation step. The reaction step is a step of reacting a bromine-containing compound, which is at least one of bromine gas and bromine trifluoride, with fluorine gas to obtain a reaction mixture containing bromine pentafluoride and bromine trifluoride. In this reaction step, the bromine-containing compound and fluorine gas are supplied into a reactor so that the molar ratio F / Br of fluorine atoms to bromine atoms is 3.0 or more and 4.7 or less, and the reaction between the bromine-containing compound and fluorine gas is carried out in the reactor. The separation step is a step of separating bromine pentafluoride and bromine trifluoride from the reaction mixture obtained in the reaction step.

[0014] When bromine pentafluoride is produced by the method of the present embodiment, the amount of fluorine gas used is less than the reaction equivalent, so that no unreacted fluorine gas remains, or even if it remains, it is only a small amount. Therefore, it is possible to reduce or simplify the process of treating the remaining fluorine gas by a method such as recovery or detoxification. In addition, since the amount of fluorine gas used is small, the amount of fluorine gas used can be reduced, and the amount of fluorine gas discharged from the reactor can be reduced.

[0015] Furthermore, the method for producing bromine pentafluoride of this embodiment has a separation step for separating bromine pentafluoride from bromine trifluoride, and therefore it is possible to produce bromine pentafluoride of high purity (for example, purity of 90% or more). In other words, in the separation step, components of the reaction mixture other than fluorine gas and bromine pentafluoride can be efficiently removed, so the method for producing bromine pentafluoride of this embodiment, which contains little fluorine gas remaining in the reaction mixture, is advantageous for obtaining high-purity bromine pentafluoride. The resulting bromine pentafluoride can be used as an etching gas, cleaning gas, fluorinating agent, etc. in the fields of organic synthesis, inorganic synthesis, atomic energy, semiconductor manufacturing, etc.

[0016] The method for producing bromine pentafluoride according to the present embodiment will be described in further detail below. [1] Reaction to produce bromine pentafluoride In the method for producing bromine pentafluoride of the present embodiment, when the bromine-containing compound is bromine gas (Br2), the raw material compounds, fluorine gas and bromine gas, react as shown in the following chemical reaction formula (1) to produce the target product, bromine pentafluoride. 5F2+ Br2 → 2BrF5 (1)

[0017] When the bromine-containing compound is bromine gas (Br2), the raw material compounds fluorine gas and bromine gas may react in two steps as shown in the following chemical reaction equations (2) and (3) to produce the target product bromine pentafluoride. 5F2+ Br2→ 2BrF3+ 2F2...(2) F2+ BrF3→ BrF5···(3) Furthermore, when the bromine-containing compound is bromine trifluoride, the raw material compounds, fluorine gas and bromine trifluoride gas, react as shown in the following chemical reaction formula (3) to produce the target product, bromine pentafluoride. F2+ BrF3→ BrF5···(3)

[0018] [2] Method of feeding raw material compounds to a reactor The method of supplying fluorine gas to the reactor in the method for producing bromine pentafluoride of this embodiment is not particularly limited, but may be, for example, a method in which a gas supply mechanism is connected to a container filled with compressed fluorine gas or a container filled with compressed mixed gas of fluorine gas and an inert gas, and fluorine gas or mixed gas is supplied to the reactor while controlling the flow rate with the gas supply mechanism. The temperature of the fluorine gas and mixed gas when supplied to the reactor is not particularly limited as long as it is a temperature at which the gas supply mechanism can operate.

[0019] The gas supply mechanism is not particularly limited as long as it has a mechanism for controlling the flow rate of gas, but from the viewpoint of availability, it is preferable to use a mass flow controller, a flow meter, etc. Below, an embodiment in which a mass flow controller is used as an example of the gas supply mechanism is shown.

[0020] In the method for producing bromine pentafluoride of this embodiment, the method for supplying a bromine-containing compound (e.g., bromine gas, bromine trifluoride) to the reactor is not particularly limited, but an example thereof includes a method in which the bromine-containing compound is heated and vaporized in a vaporizer connected to a mass flow controller, and the gas of the bromine-containing compound is supplied to the reactor while controlling the flow rate with the mass flow controller.

[0021] Alternatively, a method of vaporizing the bromine-containing compound using an inert gas can also be used. That is, a mass flow controller is connected to a container filled with compressed inert gas, and the inert gas is supplied to a vaporizer containing the bromine-containing compound while controlling the flow rate with the mass flow controller, the bromine-containing compound is vaporized in the vaporizer, and the mixed gas of the bromine-containing compound and the inert gas, the flow rate of which is controlled, is supplied to a reactor. When supplying the inert gas to the vaporizer, the inert gas may be blown into the liquid bromine-containing compound, or the inert gas may be supplied to the gas phase in the vaporizer.

[0022] The temperature in the vaporizer when the bromine-containing compound is vaporized and supplied to the reactor can be appropriately changed depending on the supply rate of the bromine-containing compound to the reactor. When the bromine-containing compound is bromine gas (Br2), the temperature in the vaporizer is preferably 10°C or higher and 60°C or lower, and when the bromine-containing compound is bromine trifluoride, the temperature in the vaporizer is preferably 30°C or higher and 130°C or lower. If the temperature in the vaporizer is within the above temperature range, the vapor pressure of the bromine-containing compound is sufficiently high, and in addition to excellent productivity of bromine pentafluoride, corrosion of the vaporizer, piping, reactor, etc. due to the bromine-containing compound is unlikely to occur.

[0023] [3] Molar ratio of fluorine atoms to bromine atoms F / Br In order to increase the conversion rate of fluorine gas to 40% or more by the production method for bromine pentafluoride of this embodiment, it is necessary to supply the bromine-containing compound and fluorine gas into the reactor so that the molar ratio F / Br of fluorine atoms to bromine atoms is 3.0 or more and 4.7 or less, and to react the bromine-containing compound with the fluorine gas.

[0024] If the molar ratio F / Br of fluorine atoms to bromine atoms is set to 3.0 or more and 4.7 or less, the amount of unreacted bromine-containing compounds is reduced, so that the productivity of bromine pentafluoride is improved while reducing the amount of unreacted fluorine gas, and in addition, separation of bromine pentafluoride from bromine trifluoride and fluorine gas in the reaction mixture can be easily performed in the separation step. In order to achieve such an effect more effectively, it is preferable that the molar ratio F / Br of fluorine atoms to bromine atoms is set to 3.3 or more and 4.5 or less.

[0025] The conversion rate of fluorine gas in the reaction can be increased to 40% or more by setting the molar ratio of fluorine atoms to bromine atoms, F / Br, to 3.0 or more and 4.7 or less and setting the residence time of the raw material compound gas in the reactor to 5 seconds or more. The residence time of the raw material compound gas in the reactor will be described in detail later.

[0026] [4] Dilution gas for diluting the raw compound In the reaction step of the method for producing bromine pentafluoride of this embodiment, a dilution gas for diluting the raw material compounds may be supplied to a reactor together with the raw material compounds, ie, the gas of a bromine-containing compound and the fluorine gas, to carry out the reaction. That is, the reaction between the bromine-containing compound and the fluorine gas may be carried out in a state where the gas of the bromine-containing compound and the fluorine gas are mixed with a dilution gas and diluted.

[0027] As the dilution gas, an inert gas that does not react with the raw material compounds, bromine-containing compound and fluorine gas, the target product, bromine pentafluoride, and the intermediate or by-product, bromine trifluoride, may be used. The type of inert gas is not particularly limited, but examples thereof include nitrogen gas, argon, and helium. Among these inert gases, nitrogen gas is preferred as the dilution gas from the viewpoints of availability and low cost.

[0028] In the reaction step of the method for producing bromine pentafluoride of this embodiment, the bromine-containing compound gas and fluorine gas are mixed with a dilution gas to carry out the reaction in a diluted state, which makes it easy to control the reaction by suppressing the occurrence of excessive heat generation locally, and therefore makes it possible to suppress runaway reaction and corrosion of the reactor.

[0029] When bromine gas and fluorine gas are used as raw material compounds, the reactions shown in the above chemical reaction formulas (1), (2), and (3) proceed, but the reaction between bromine gas and fluorine gas proceeds violently, so there is a risk of localized reactions or runaway reactions. To prevent such problems from occurring, it is effective to use a dilution gas.

[0030] On the other hand, when bromine trifluoride gas and fluorine gas are used as the raw material compounds, the reaction shown in the above chemical reaction formula (3) proceeds, but since the reaction between bromine trifluoride gas and fluorine gas proceeds relatively slowly, it is not necessary to mix a large amount of diluent gas with the raw material compounds. However, the use of a diluent gas is preferable because it reduces the risk of localized reactions or runaway reactions.

[0031] The amount of the diluent gas supplied into the reactor together with the raw material compound is not particularly limited, but is preferably 30% by volume or more, more preferably 50% by volume or more, of the total volume of the bromine-containing compound gas, fluorine gas, and diluent gas in the reactor. If the amount is 30% by volume or more, the risk of localized reactions or runaway reactions can be sufficiently reduced, so that bromine pentafluoride can be produced more safely.

[0032] In order to increase the separation efficiency of the target product in the separation step, the amount of diluent gas supplied into the reactor together with the raw material compounds is preferably 99 vol % or less, and more preferably 90 vol % or less, of the total volume of the gas in the reactor consisting of the bromine-containing compound gas, the fluorine gas and the diluent gas.

[0033] [5] Temperature inside the reactor In the method for producing bromine pentafluoride of this embodiment, the reaction of the bromine-containing compound with fluorine gas is preferably carried out at a temperature of 100° C. or higher and 400° C. or lower. At a temperature of 100° C. or higher and 400° C. or lower, the reaction of the bromine-containing compound with fluorine gas proceeds smoothly, and the conversion rate of fluorine gas can be 40% or higher. Therefore, the amount of remaining unreacted fluorine gas is reduced, and the process of recovering the remaining unreacted fluorine gas, treating it by a method for detoxification, etc. can be greatly reduced or simplified.

[0034] In addition, at temperatures between 100°C and 400°C, corrosion inside the reactor due to the raw material compounds (fluorine gas, bromine-containing compounds) and the target product (bromine pentafluoride) is unlikely to occur, so there is no need to use expensive materials such as platinum as the reactor material. Furthermore, if the temperature is 100°C or higher and 400°C or lower, the reverse reaction of chemical reaction formula (3) is unlikely to proceed, so that decomposition of the target product, bromine pentafluoride, is unlikely to occur during the reaction.

[0035] The method for reacting a bromine-containing compound with fluorine gas at a temperature of 100° C. or higher and 400° C. or lower is not particularly limited, but an example of the method includes a method in which a bromine-containing compound gas and fluorine gas are supplied into a reactor while the temperature inside the reactor is adjusted to 100° C. or higher and 400° C. or lower.

[0036] The method for adjusting the temperature inside the reactor to 100° C. or more and 400° C. or less is not particularly limited, but examples thereof include a method for adjusting the temperature inside the reactor by heating the reactor with a heating means such as an electric heater or steam, or, in some cases, cooling the reactor with a jacket through which a refrigerant is introduced.

[0037] When the reaction of the bromine-containing compound with fluorine gas is carried out with the catalyst placed in the reactor, the reactor may be heated with the catalyst placed in the reactor to adjust the reactor and the catalyst to the desired temperatures, and then the bromine-containing compound gas and fluorine gas may be fed into the reactor. The higher the temperature of the catalyst, the higher the conversion rate of the fluorine gas.

[0038] [6] Pressure inside the reactor In the method for producing bromine pentafluoride of this embodiment, the pressure inside the reactor during the reaction can be set arbitrarily depending on the method for separating and recovering the bromine-containing compound and the method for recovering the target product, bromine pentafluoride.

[0039] However, when the reaction of a bromine-containing compound with fluorine gas is carried out under pressurized conditions, the reaction equilibrium is shifted toward the production of bromine pentafluoride, and therefore, the productivity of bromine pentafluoride can be improved by increasing the pressure inside the reactor. On the other hand, in order to reduce the risk of leakage of toxic and corrosive fluorine gas, bromine gas, bromine trifluoride gas, and bromine pentafluoride gas, it is preferable not to increase the pressure inside the reactor during the reaction more than necessary.

[0040] Considering these points, the reaction of the bromine-containing compound with the fluorine gas is preferably carried out under a pressure of 0.05 MPa or more and 0.5 MPa or less, more preferably under a pressure of 0.1 MPa or more and 0.5 MPa or less, and even more preferably under a pressure of 0.1 MPa or more and 0.2 MPa or less. In the present invention, the pressure means absolute pressure unless otherwise specified.

[0041] [7] The time that the raw material gas remains in the reactor In the method for producing bromine pentafluoride of the present embodiment, the time during which the gas of the raw material compound supplied into the reactor remains in the reactor (hereinafter, also referred to as the "residence time") can be appropriately set in consideration of the yield and productivity of bromine pentafluoride.

[0042] At a reaction temperature at which the reverse reaction of decomposing bromine pentafluoride into bromine trifluoride and fluorine gas does not become significant, the conversion rate of fluorine gas increases as the residence time increases. However, since the need to increase the volume of the reactor arises with an increase in the residence time, it is preferable to have a short residence time and a small volume of the reactor in consideration of the productivity of bromine pentafluoride. Considering these factors, when the reaction of a bromine-containing compound with fluorine gas is carried out under temperature conditions of 100°C or higher and 400°C or lower, the residence time is preferably 5 seconds or longer, which makes it possible to achieve a conversion rate of fluorine gas of 40% or higher.

[0043] [8] Catalyst In the method for producing bromine pentafluoride of the present embodiment, in order to control the reaction to obtain bromine pentafluoride, a catalyst may be placed in a reactor and allowed to coexist with raw material compounds such as a bromine-containing compound and fluorine gas during the reaction, thereby carrying out the reaction of the bromine-containing compound with fluorine gas.

[0044] The catalyst preferably has low reactivity with bromine-containing compounds, fluorine gas, and bromine pentafluoride, and examples of the compound used as the catalyst include at least one of a metal oxide and a metal fluoride, and the metal is at least one of the metals belonging to the third and fourth periods of the periodic table.

[0045] Specific examples of metal fluorides include aluminum fluoride (AlF3), calcium fluoride (CaF2), iron (III) fluoride (FeF3), cobalt (II) fluoride (CoF2), nickel (II) fluoride (NiF2), copper (I) fluoride (CuF), potassium fluoride (KF), magnesium fluoride (MgF2), and sodium fluoride (NaF), and examples of metal oxides include aluminum oxide (Al2O3 such as α-Al2O3), nickel (II) oxide (NiO), iron (III) oxide (Fe2O3), and cobalt (II) oxide (CoO). Considering low reactivity with bromine-containing compounds, fluorine gas, and bromine pentafluoride and easy availability, AlF3, FeF3, CoF2, NiF2, and α-Al2O3 are more preferable.

[0046] In addition, the catalyst preferably does not contain moisture. If a catalyst containing moisture is used, fluorine gas, bromine gas, bromine trifluoride, or bromine pentafluoride reacts with moisture during the production of bromine pentafluoride to produce hydrogen fluoride (HF) or hydrogen bromide (HBr), which may cause problems such as the hydrogen fluoride or hydrogen bromide being mixed into the target product bromine pentafluoride, or the corrosion of the reactor or piping being accelerated. When a catalyst containing moisture is used, it is preferable to perform a pretreatment in which the catalyst is dehydrated by a means such as heating and drying under an inert gas flow or vacuum drying. The shape of the catalyst is not particularly limited as long as it allows efficient contact with the fluorine gas, bromine gas, and bromine trifluoride gas flowing through the reactor and does not cause these gases to clog the reactor.

[0047] As a specific example, a metal fluoride can be produced by fluorinating the metal surface by contacting a metal porous body or a metal mesh with fluorine gas, chlorine trifluoride gas (ClF3), iodine heptafluoride gas (IF7), or bromine pentafluoride gas at high temperature, and the like, and the like can be used as the catalyst. Alternatively, a commercially available metal fluoride or metal oxide powder molded into pellets, or a commercially available molded product of a metal fluoride or metal oxide can be used as it is.

[0048] However, from the viewpoint of the large contact area per unit volume between the gas and the metal surface and the efficient progress of the reaction for producing bromine pentafluoride, the catalyst is preferably in the form of a porous body, mesh, or the like. In particular, from the viewpoint of ease of availability, a porous body having a pore size of 0.3 mm or more and 3.2 mm or less, a specific surface area of ​​500 m 2 / m 3 More than 10000m 2 / m 3 More preferred are the following porous bodies and meshes with a wire diameter of 0.04 mm or more and 0.8 mm or less and a mesh size of 0.04 mm or more and 0.98 mm or less.

[0049] [9] Reactor structure The reactor used in the method for producing bromine pentafluoride of this embodiment preferably has a structure that allows the bromine-containing compound gas, which is the raw material compound, and the fluorine gas to come into contact with the catalyst, and a flow reactor or a batch reactor can be used. The reactor may be tubular or tank-shaped, and the tubular type may be single-tube or multi-tube, and the catalyst may be packed in a fluidized bed or a fixed bed. The reactor is preferably shaped like a single tube or multi-tube, and the catalyst is preferably packed in a fixed bed.

[0050] When using a flow reactor, it is necessary to simultaneously feed the bromine-containing compound gas and fluorine gas, which are raw material compounds, into the flow reactor. When using a batch reactor, the bromine-containing compound gas and fluorine gas may be mixed in advance and introduced into the batch reactor, or the bromine-containing compound gas and fluorine gas may be separately fed into the batch reactor. When the bromine-containing compound gas and fluorine gas are separately fed into the batch reactor, the order in which these raw material compounds are fed into the reactor is not particularly limited, and the bromine-containing compound gas and fluorine gas may be simultaneously fed into the reactor, or may be fed into the reactor successively.

[0051] However, in the method for producing bromine pentafluoride according to the present embodiment, in consideration of obtaining bromine pentafluoride continuously, it is preferable to use a flow-type tubular reactor as the reactor. The shape of the flow-type tubular reactor is not particularly limited as long as it can pass bromine-containing compound gas, fluorine gas, etc., but when a catalyst such as NiF2 is placed in the reactor, it is preferable that the reactor has a cavity so that the catalyst can be accommodated and the gas can be passed through while the catalyst is accommodated.

[0052] When a tubular reactor is used in the method for producing bromine pentafluoride of this embodiment, if the inner surface of the tubular reactor is rough, resistance occurs when the gas flows through the tubular reactor, and gas retention, increased pressure loss, abnormal heat generation due to local reactions, etc. occur, which may make it difficult to control the reaction. Therefore, the inner surface of the tubular reactor is preferably smooth. Specifically, it is preferable to use a bright annealed tube with a smooth inner surface, which is produced by a method including a process of heating and quenching in a non-oxidizing atmosphere such as an inert gas or vacuum, as the tubular reactor.

[0053]

[10] Reactor Material The reactor used in the method for producing bromine pentafluoride of this embodiment must be made of a material that is resistant to corrosion by fluorine gas and bromine-containing compound gas. Specific examples of the material include metals such as nickel, nickel-based alloys, aluminum, stainless steel, and platinum, and ceramics such as alumina. Specific examples of nickel-based alloys include Inconel (registered trademark), Hastelloy (registered trademark), and Monel (registered trademark).

[0054] When the temperature inside the reactor is set to 150°C or higher, it is preferable to select nickel, nickel-based alloys, platinum, and alumina, which are particularly excellent in corrosion resistance, from among the above materials, and nickel and nickel-based alloys, which are easily available and relatively inexpensive, are particularly preferable. Note that the metal oxides and metal fluorides used as catalysts can also be used as the materials for the reactor.

[0055] A bright annealing tube made of nickel is preferably used as the reactor used in the method for producing bromine pentafluoride of this embodiment. Nickel has excellent corrosion resistance against high-temperature fluorine gas, bromine gas, bromine trifluoride gas, and bromine pentafluoride gas used in the method for producing bromine pentafluoride of this embodiment, and the bright annealing tube has a smooth surface, so that the risk of abnormal reactions between the gases and metal residues and damage to the reactor can be minimized.

[0056] When the method for producing bromine pentafluoride of this embodiment is carried out using a nickel reactor, the inner surface of the reactor may be fluorinated by fluorine gas, bromine trifluoride gas, or bromine pentafluoride gas, and may change to NiF2. However, as can be seen from the fact that NiF2 can be used as a catalyst in the method for producing bromine pentafluoride of this embodiment, it is acceptable for the inner surface of the reactor to change to NiF2. Similarly, even if the material of the reactor is one of the metals exemplified above, it is acceptable for the inner surface of the reactor to be fluorinated by the reaction of the metal with fluorine gas, bromine trifluoride gas, or bromine pentafluoride gas. As the material for the bright annealed tube, in addition to nickel, nickel-based alloys (e.g., Inconel (registered trademark), Hastelloy (registered trademark), Monel (registered trademark)) containing 50 mass% or more of nickel and also containing iron, copper, chromium, molybdenum, etc., and NiF2 can be used.

[0057]

[11] Cooling collection vessel The method for producing bromine pentafluoride according to the present embodiment includes a separation step in which bromine pentafluoride and bromine trifluoride in the reaction mixture obtained in the reaction step are separated in the separation step. The separation step may include a cooling step in which the reaction mixture is cooled to separate the mixture into a gas component containing bromine pentafluoride and a liquid solid component containing bromine trifluoride.

[0058] For example, a cold collection vessel can be used to cool the reaction mixture. When the reaction mixture obtained in the reaction step is supplied to a cold collection vessel and cooled to a temperature at which bromine trifluoride solidifies or liquefies but bromine pentafluoride does not solidify or liquefy, bromine trifluoride and bromine pentafluoride can be separated. For example, when cooled to 0°C, most of the bromine trifluoride becomes solid and is collected in the cold collection vessel (hereinafter, sometimes referred to as "cold collection vessel for collecting bromine trifluoride"), but most of the bromine pentafluoride passes through the cold collection vessel in the form of gas.

[0059] Although most of the bromine trifluoride becomes solid in the cold collection vessel, some liquid or gaseous bromine trifluoride may also be present and pass through the cold collection vessel, so it is preferable to further carry out an operation to separate bromine trifluoride from the gas that has passed through the cold collection vessel. This operation will be described in detail in Section

[12] . When a diluent gas such as nitrogen gas is used in the reaction step, the diluent gas is entrained in the reaction mixture, so that although some of the bromine pentafluoride is collected in the cold collection vessel as a liquid, most of the bromine pentafluoride is likely to pass through the cold collection vessel as a gas.

[0060] The cooling temperature of the reaction mixture in the cold collection vessel is preferably in the range of -20°C to 30°C, more preferably in the range of -10°C to 20°C. Within this temperature range, bromine trifluoride can be collected with high efficiency, and since the amount of bromine pentafluoride collected is small, the separation efficiency of bromine pentafluoride and bromine trifluoride is high. If collection is performed at a temperature below the melting point of bromine trifluoride, there is a concern that bromine trifluoride will solidify in the piping connected to the cold collection vessel, causing blockage of the piping. However, if a diluent gas is used in the reaction step and the diluent gas is entrained in the reaction mixture, blockage of the piping due to solidification of bromine trifluoride can be suppressed. The pressure inside the cold collection vessel here is preferably 0.05 MPa to 0.5 MPa, more preferably 0.1 MPa to 0.3 MPa.

[0061] Bromine pentafluoride that has passed through the cooling trapping vessel is supplied to another cooling trapping vessel (hereinafter, sometimes referred to as a "cooling trapping vessel for collecting bromine pentafluoride") and cooled to a temperature at which bromine pentafluoride solidifies or liquefies, whereby bromine pentafluoride can be collected in the other cooling trapping vessel. The cooling temperature in the cooling trapping vessel for collecting bromine pentafluoride is not particularly limited as long as it is a temperature lower than the boiling point of bromine pentafluoride. However, in order to improve the efficiency of collecting bromine pentafluoride, it is preferable to cool to a temperature at which the vapor pressure of bromine pentafluoride is sufficiently low. Specifically, the cooling temperature in the cooling trapping vessel for collecting bromine pentafluoride is preferably in the range of -100°C or higher and 0°C or lower, more preferably in the range of -80°C or higher and -20°C or lower.

[0062] If the trapping is performed at a temperature below the melting point of bromine pentafluoride, there is a concern that bromine pentafluoride may solidify in the piping connected to the cooling trapping vessel for trapping bromine pentafluoride, causing blockage of the piping, but if a dilution gas is used in the reaction step and the dilution gas is entrained in the reaction mixture, blockage of the piping due to solidification of bromine pentafluoride can be suppressed. The pressure inside the cooling trapping vessel here is preferably 0.05 MPa or more and 0.5 MPa or less, more preferably 0.1 MPa or more and 0.3 MPa or less.

[0063] The cold trapping vessel for trapping bromine trifluoride and the cold trapping vessel for trapping bromine pentafluoride must be made of a material that is resistant to reaction with fluorine gas, bromine gas, bromine trifluoride gas, and bromine pentafluoride gas and has corrosion resistance. Specific examples of the material include metals such as nickel, nickel-based alloys, aluminum, stainless steel, and platinum, and ceramics such as alumina. Specific examples of nickel-based alloys include Inconel (registered trademark), Hastelloy (registered trademark), and Monel (registered trademark). In addition, among the surfaces of the cold trapping vessels made of the above metals, the inner surface that comes into contact with fluorine gas and the like may be fluorinated. Among these, Monel (registered trademark), aluminum, alumina, and stainless steel, which are easily available and relatively inexpensive, are particularly preferable.

[0064]

[12] Adsorption tower As described above, the method for producing bromine pentafluoride according to the present embodiment includes a separation step, in which bromine pentafluoride and bromine trifluoride in the reaction mixture obtained in the reaction step are separated in the separation step. The separation step includes a cooling step in which the reaction mixture is cooled to separate the mixture into a gas component containing bromine pentafluoride and a liquid solid component containing bromine trifluoride, and may further include an adsorption step in which the gas component containing bromine pentafluoride obtained in the cooling step is brought into contact with an adsorbent to adsorb bromine trifluoride contained in the gas component containing bromine pentafluoride onto the adsorbent. For example, an adsorption tower can be used for adsorption of bromine trifluoride.

[0065] The type of adsorbent to be filled in the adsorption tower is not particularly limited as long as it is difficult to adsorb bromine pentafluoride and can adsorb bromine trifluoride, but at least one fluoride of metals belonging to Groups 1 and 2 of the periodic table can be used. As shown in chemical reaction formula (4), these metal fluorides react with bromine trifluoride to form a salt, but do not react with bromine pentafluoride to form a salt, so that selective separation of bromine trifluoride can be performed. In addition, M in chemical reaction formula (4) represents a metal, and x represents 1 or 2. BrF3+MF x → MBrF x+3 (4)

[0066] Among these metal fluorides, at least one selected from lithium fluoride (LiF), sodium fluoride (NaF), potassium fluoride (KF), rubidium fluoride (RbF), cesium fluoride (CsF), magnesium fluoride (MgF2), and calcium fluoride (CaF2) is preferred, and from the viewpoint of availability, at least one selected from LiF, NaF, KF, MgF2, and CaF2 is more preferred.

[0067] The adsorption temperature of bromine trifluoride, i.e., the temperature in the adsorption tower when the gas component containing bromine pentafluoride obtained by the cooling step is brought into contact with the adsorbent in the adsorption tower, is preferably in the range of 0°C to 100°C, more preferably in the range of 20°C to 70°C. Within this temperature range, solidification of bromine trifluoride and liquefaction of bromine pentafluoride are unlikely to occur, so that the adsorption tower and the piping connected to the adsorption tower are unlikely to be clogged, and in addition, desorption of bromine trifluoride from the adsorbent is unlikely to occur, so that bromine trifluoride can be sufficiently separated. The pressure inside the adsorption tower is preferably 0.05 MPa to 0.5 MPa, more preferably 0.1 MPa to 0.3 MPa.

[0068] The adsorption tower needs to be made of a material that is resistant to reaction with fluorine gas, bromine gas, bromine trifluoride gas, and bromine pentafluoride gas and has corrosion resistance. Specific examples of the material include metals such as nickel, nickel-based alloys, aluminum, stainless steel, and platinum, and ceramics such as alumina. Specific examples of nickel-based alloys include Inconel (registered trademark), Hastelloy (registered trademark), and Monel (registered trademark). Of the surfaces of the adsorption towers made of the above metals, the inner surface that comes into contact with fluorine gas and the like may be fluorinated.

[0069]

[13] Example of a bromine pentafluoride manufacturing plant The method for producing bromine pentafluoride according to the present embodiment can be carried out in a bromine pentafluoride production apparatus shown in Fig. 1. The bromine pentafluoride production apparatus shown in Fig. 1 includes a reactor 1 for reacting a gas of a bromine-containing compound, which is at least one of bromine and bromine trifluoride, with fluorine gas, a fluorine gas supplying device 2 for supplying fluorine gas to the reactor 1, a mass flow controller 11 for controlling the flow rate of the fluorine gas supplied from the fluorine gas supplying device 2 to the reactor 1, an inert gas supplying device 3 for supplying an inert gas to the reactor 1, a mass flow controller 12 for controlling the flow rate of the inert gas supplied from the inert gas supplying device 3 to the reactor 1, and a vaporizer 4 for accommodating a bromine-containing compound 6, which is at least one of liquid bromine and liquid bromine trifluoride, vaporizing the liquid bromine-containing compound 6, and supplying it to the reactor 1.

[0070] A metal (not shown) serving as a catalyst is placed inside the reactor 1. The reactor 1 also includes a heating device (not shown) such as an electric furnace, so that the temperature inside the reactor 1 can be controlled to any desired temperature. The vaporizer 4 is equipped with an inert gas supplying device 5 that blows an inert gas into the liquid bromine-containing compound 6 in the vaporizer 4, a mass flow controller 14 that controls the flow rate of the inert gas supplied from the inert gas supplying device 5 to the vaporizer 4, and a heating device 13 that heats the liquid bromine-containing compound 6 in the vaporizer 4.

[0071] The bromine pentafluoride production apparatus shown in FIG. 1 further includes a pressure gauge 15 for measuring the pressure inside the reactor 1, a first cooling and collecting vessel 7 (corresponding to the above-mentioned "cooling and collecting vessel for collecting bromine trifluoride") for cooling a reaction mixture containing bromine pentafluoride and bromine trifluoride, collecting bromine trifluoride and passing the bromine pentafluoride through the reaction mixture to separate bromine pentafluoride and bromine trifluoride, an adsorption tower 8 filled with a metal fluoride as an adsorbent, and a second cooling and collecting vessel 9 (corresponding to the above-mentioned "cooling and collecting vessel for collecting bromine pentafluoride") for cooling and collecting the bromine pentafluoride that has passed through the adsorption tower 8.

[0072] The first cold trapping vessel 7 is provided with a cooling tank 19, and the temperature inside the first cold trapping vessel 7 can be controlled by the cooling tank 19. Similarly, the second cold trapping vessel 9 is provided with a cooling tank 20, and the temperature inside the second cold trapping vessel 9 can be controlled by the cooling tank 20.

[0073] The reactor 1, the first cold trapping vessel 7, the adsorption tower 8, and the second cold trapping vessel 9 are arranged in series in the order shown, and are connected to each other by piping. A pressure regulating valve 16, a Fourier transform infrared spectrophotometer 17, and an ultraviolet-visible spectrophotometer 18 are installed in the piping connecting the reactor 1 and the first cooling collection vessel 7, and the pressure regulating valve 16, the Fourier transform infrared spectrophotometer 17, and the ultraviolet-visible spectrophotometer 18 are arranged in series in this order from the reactor 1 side.

[0074] Next, an example of a method for producing bromine pentafluoride using the bromine pentafluoride production apparatus shown in FIG. 1 will be described. The liquid bromine-containing compound 6 in the vaporizer 4 is heated by the heating device 13 to vaporize the bromine-containing compound 6. As a result, the liquid bromine-containing compound 6 and the gas of the bromine-containing compound 6 are present in the vaporizer 4. An inert gas is blown from the inert gas supply device 5 into the liquid bromine-containing compound 6 in the vaporizer 4 while controlling the flow rate by the mass flow controller 14. By blowing in the inert gas, the gas of the bromine-containing compound 6 is supplied from the vaporizer 4 to the reactor 1 while being diluted with the inert gas.

[0075] On the other hand, fluorine gas is supplied from the fluorine gas supplying device 2 to the reactor 1 while controlling the flow rate by the mass flow controller 11, and inert gas is supplied from the inert gas supplying device 3 to the reactor 1 while controlling the flow rate by the mass flow controller 12. At this time, the concentration of the fluorine gas supplied to the reactor 1 can be controlled by the mass flow controllers 11 and 12.

[0076] That is, if only fluorine gas is supplied and no inert gas is supplied, fluorine gas with a concentration of 100% can be supplied to the reactor 1. In addition, if both fluorine gas and inert gas are supplied, fluorine gas diluted with the inert gas to an arbitrary concentration can be supplied to the reactor 1.

[0077] In the following, fluorine gas diluted to x% by volume with inert gas will be referred to as "x% by volume fluorine gas." For example, fluorine gas diluted to 20% by volume with inert gas will be referred to as "20% by volume fluorine gas," fluorine gas diluted to 50% by volume with inert gas will be referred to as "50% by volume fluorine gas," and fluorine gas not diluted with inert gas will be referred to as "100% by volume fluorine gas."

[0078] A bromine-containing compound gas and fluorine gas are supplied to the reactor 1 to react with the bromine-containing compound gas and the fluorine gas, and the reaction is carried out by supplying the bromine-containing compound gas and the fluorine gas so that the molar ratio F / Br of fluorine atoms to bromine atoms is 3.0 to 4.7. During the reaction, the pressure in the reactor 1 is measured by a pressure gauge 15. As a result of the reaction, a gaseous reaction mixture containing bromine pentafluoride and bromine trifluoride is obtained. When an inert gas is supplied to the reactor 1 together with the bromine-containing compound gas and fluorine gas, a gaseous reaction mixture containing bromine pentafluoride, bromine trifluoride, and the inert gas is obtained. However, the reaction mixture may contain unreacted fluorine gas, bromine gas, or bromine monofluoride (BrF) as a by-product.

[0079] The resulting reaction mixture is sent to a Fourier transform infrared spectrophotometer 17 and an ultraviolet-visible spectrophotometer 18 while adjusting the pressure to about 0.1 to 0.2 MPa with a pressure regulating valve 16, and the components of the reaction mixture are quantitatively determined by Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy, and then sent to the first cold trapping vessel 7. Since the temperature inside the first cold trapping vessel 7 is controlled to a predetermined temperature by a cooling tank 19, the reaction mixture is separated into a gas component containing bromine pentafluoride and a liquid / solid component containing bromine trifluoride.

[0080] More specifically, most of the bromine trifluoride in the reaction mixture solidifies in the first cold collection vessel 7 and is collected in the first cold collection vessel 7. Reference numeral 21 in FIG. 1 indicates solidified bromine trifluoride. If unreacted bromine gas is contained in the reaction mixture, the unreacted bromine gas is also solidified and collected in the first cold collection vessel 7. On the other hand, although some of the bromine pentafluoride in the reaction mixture is liquefied and collected, most of it is in gaseous form. Therefore, a mixed gas containing gaseous bromine pentafluoride and at least one of unreacted fluorine gas and inert gas is discharged from the first cold collection vessel 7 and sent to the adsorption tower 8.

[0081] Although a small amount of bromine trifluoride is mixed into the mixed gas that has passed through the first cooling collection vessel 7, this bromine trifluoride forms a complex salt with the metal fluoride filled in the adsorption tower 8, and therefore the bromine trifluoride is selectively adsorbed and separated from the mixed gas by the adsorption tower 8. Therefore, the mixed gas that has passed through the adsorption tower 8 contains almost no bromine trifluoride.

[0082] The mixed gas containing bromine pentafluoride that has passed through the adsorption tower 8 is supplied to a second cold trapping vessel 9. Since the temperature inside the second cold trapping vessel 9 is controlled to a predetermined temperature by a cooling tank 20, the bromine pentafluoride in the mixed gas is solidified or liquefied and collected. Reference numeral 22 in FIG. 1 indicates the solidified or liquefied bromine pentafluoride. The bromine pentafluoride obtained here has a high purity of, for example, 90% or more.

[0083] At least one of the unreacted fluorine gas and the inert gas in the mixed gas is not collected in the second cooling collection vessel 9 either, and is discharged from the bromine pentafluoride manufacturing apparatus. The bromine pentafluoride production apparatus of Fig. 2, which is a modified example of the bromine pentafluoride production apparatus of Fig. 1, does not include the adsorption tower 8, and the first cold trapping vessel 7 and the second cold trapping vessel 9 are directly connected by piping. Even when the bromine pentafluoride production apparatus of Fig. 2 having such a structure is used, bromine pentafluoride can be produced in the same manner as the bromine pentafluoride production apparatus of Fig. 1. EXAMPLES

[0084] The present invention will be described more specifically below with reference to examples and comparative examples. [Catalyst Preparation Example 1] Nickel porous body with 99% purity (manufactured by Nilaco Corporation, pore size 0.5 mm, specific surface area 7500 m 2 / m 3 The nickel porous body was placed in a bright annealing tube (inner diameter 25.4 mm, length 300 mm) equipped with an electric heater and a pressure gauge. The bright annealing tube was heated by the electric heater, and the temperature of the nickel porous body was raised to 300°C. The nickel bright annealed tube is a bright annealed tube made of Ni201 (nickel purity of 99.7% by mass or more) standardized in JIS H4552:2000 "Nickel and nickel alloy seamless tubes".

[0085] Next, 50 volume percent fluorine gas was introduced at a flow rate of 200 sccm from one end (hereinafter referred to as the "inlet") of the bright annealing tube, and exhausted from the other end (hereinafter referred to as the "outlet"). This caused the nickel constituting the nickel porous body to react with the fluorine gas, resulting in a porous body made of NiF2. At this time, the pressure inside the bright annealing tube was set to 0.1 MPa. Here, "sccm" refers to the volumetric flow rate (cm) per minute normalized under conditions of 0°C and 1 atm. 3 ).

[0086] The completion of the reaction between nickel and fluorine gas to produce NiF2 was confirmed by the following method. The exhaust gas discharged from the outlet of the bright annealing tube was passed through a 10 mass% potassium iodide (KI) aqueous solution for 5 minutes, and the potassium iodide aqueous solution through which the exhaust gas was passed was subjected to oxidation-reduction titration using a 0.1 N sodium thiosulfate aqueous solution. The concentration of fluorine gas discharged from the outlet of the bright annealing tube was quantified by this oxidation-reduction titration. When the concentration of fluorine gas discharged from the outlet of the bright annealing tube became equal to the concentration of fluorine gas supplied from the inlet of the bright annealing tube, the reaction between nickel and fluorine gas was determined to be complete.

[0087] The redox titration was performed after 50% by volume fluorine gas had been passed through the bright annealing tube for 3 hours, thereby confirming the completion of the reaction.Then, ion chromatography and inductively coupled plasma atomic emission spectrometry were performed using the following equipment and conditions to confirm the production of NiF2.

[0088] (Ion Chromatography) Approximately 50 mg of sample was weighed into a 50 mL container, 40 mL of pure water was added and stirred, and further pure water was added to make a constant volume of 50 mL to obtain a sample solution. This sample solution was further diluted 100 times with pure water, and ion chromatography was performed on this diluted sample solution under the following conditions.

[0089] Measurement equipment: DIONEX ICS-2000 manufactured by Nippon Dionex Co., Ltd. Eluent: Potassium hydroxide solution (gradient elution at 4-40 mM concentration) ·Flow rate: 1.0mL / min Column: DIONEX AG18 / AS18 manufactured by Nippon Dionex Co., Ltd. Column inner diameter: 4mm Column temperature: 30℃ Sample injection volume: 25μL Detector: Electrical conductivity detector

[0090] (Inductively Coupled Plasma Atomic Emission Spectroscopy) The same sample solution as in the case of ion chromatography was further diluted 100-fold with dilute nitric acid, and this diluted sample solution was subjected to inductively coupled plasma optical emission spectrometry using an inductively coupled plasma optical emission spectrometry analyzer Vista-PRO manufactured by Hitachi High-Tech Science Corporation. The NiF2 porous body (mass 48 g (0.5 mol)) obtained as described above was used as a catalyst, and a bright annealing tube with this NiF2 porous body placed inside was used as a reactor for producing bromine pentafluoride.

[0091] [Catalyst Preparation Example 2] The nickel porous body was replaced with a 99% purity iron porous body (manufactured by Taisei Kogyo Co., Ltd., pore size 0.8 mm, specific surface area 5700 m 2 / m 3 A catalyst (FeF3 porous body) was prepared and analyzed in the same manner as in Catalyst Preparation Example 1, except that the amount of the catalyst used was changed to 27.9 g (0.5 mol) (mass of 27.9 g (0.5 mol)).

[0092] [Catalyst Preparation Example 3] Nickel porous body was replaced with 99% pure cobalt porous body (manufactured by Nilaco Corporation, pore size 2.0 mm, specific surface area 6200 m 2 / m 3 A catalyst (CoF2 porous body) was prepared and analyzed in the same manner as in Catalyst Preparation Example 1, except that the amount of the catalyst used was changed to 29.5 g (0.5 mol) (mass of 29.5 g (0.5 mol)).

[0093] [Catalyst Preparation Example 4] The nickel porous body was then mixed with a 99% purity aluminum porous body (manufactured by Taisei Kogyo Co., Ltd., pore size 0.5 mm, specific surface area 7000 m 2 / m 3 A catalyst (AlF3 porous body) was prepared and analyzed in the same manner as in Catalyst Preparation Example 1, except that the amount of the catalyst used was changed to 27.9 g (0.5 mol) (mass of 27.9 g (0.5 mol)).

[0094] Example 1 Bromine pentafluoride was produced using an apparatus similar to that shown in Fig. 1. A bright annealing tube (reactor) equipped with 48 g of the catalyst (NiF2 porous body) prepared in Catalyst Preparation Example 1 was heated in an electric furnace, and the temperature inside the bright annealing tube (i.e., reaction temperature) was set to 280°C. Therefore, the temperature of the catalyst was also 280°C.

[0095] Next, a vaporizer containing liquid bromine trifluoride as a bromine-containing compound was heated to 90°C, and then nitrogen gas was blown into the liquid bromine trifluoride to obtain bromine trifluoride gas, which was then supplied to a bright annealing tube. The flow rate of the nitrogen gas blown into the liquid bromine trifluoride was 300sccm converted at 0°C and 101kPa, and the flow rate of the bromine trifluoride gas supplied to the bright annealing tube was 102sccm.

[0096] At the same time that bromine trifluoride gas was supplied to the bright annealing tube, 100 volume percent fluorine gas was supplied to the bright annealing tube at a flow rate of 76 sccm, and nitrogen gas, which is a dilution gas, was supplied to the bright annealing tube at a flow rate of 732 sccm. In other words, a gas of raw material compounds with a composition ratio (volume ratio) of bromine trifluoride: fluorine gas: nitrogen gas = 11.2: 8.4: 80.4 when the total is taken as 100 was supplied to the bright annealing tube. Therefore, the molar ratio F / Br of fluorine atoms and bromine atoms in the raw material compound gas was 4.5. At this time, the pressure in the bright annealing tube was set to 0.1 MPa. The time that the raw material compound gas remained in the bright annealing tube was 5 seconds.

[0097] Under these conditions, the gas of the raw material compound was passed through the bright annealing tube for 1 hour to continuously carry out the reaction of fluorine gas and bromine trifluoride to obtain bromine pentafluoride. Then, the gaseous reaction mixture discharged from the bright annealing tube was subjected to Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy to measure the composition of the reaction mixture (concentrations of fluorine gas, bromine trifluoride, bromine pentafluoride, etc.). At this time, the amount of nitrogen gas was assumed to be unchanged, and the composition of the reaction mixture and the conversion rate of fluorine gas were calculated.

[0098] The Fourier transform infrared spectroscopic analysis was performed using a Fourier transform infrared spectrophotometer Nicolet iS5 manufactured by Thermo Fisher Scientific Co., Ltd., and the concentrations of bromine trifluoride and bromine pentafluoride were measured by the analysis. The ultraviolet-visible spectroscopic analysis was performed using a ultraviolet-visible spectrophotometer double beam spectrophotometer U-2900 manufactured by Hitachi High-Tech Science Co., Ltd., and the concentrations of bromine gas and fluorine gas were measured by the analysis.

[0099] The reaction conditions, the composition of the raw material gas, the composition of the reaction mixture, and the conversion rate of fluorine gas are shown in Table 1. The molar ratio F / Br of fluorine atoms to bromine atoms in the raw material compound can be calculated by substituting the concentrations (volume %) of fluorine gas, bromine gas, and bromine trifluoride gas in the raw material compound into the following formula. F / Br = [3 x concentration of bromine trifluoride gas (volume%) + 2 x concentration of fluorine gas (volume%)] / [concentration of bromine trifluoride gas (volume%) + 2 x concentration of bromine gas (volume%)]

[0100] The conversion rate (yield) of fluorine gas can be calculated by substituting the concentration (volume %) of fluorine gas in the raw material compound gas and the concentration (volume %) of fluorine gas in the reaction mixture into the following formula. Conversion rate (%) = [fluorine gas concentration (volume %) in the raw material compound gas - fluorine gas concentration (volume %) in the reaction mixture] / fluorine gas concentration (volume %) in the raw material compound gas

[0101] [Table 1]

[0102] Next, the gaseous reaction mixture discharged from the bright annealing tube was fed to a first stainless steel cooling collection vessel (volume 500 mL) cooled to 0°C under a pressure of 0.1 MPa, where it was cooled and bromine trifluoride was collected. The composition of the material collected in the first cooling collection vessel was measured by Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy. The results are shown in Table 2.

[0103] Next, the gaseous reaction mixture that passed through the first cooling collection vessel was passed through a stainless steel tube (inner diameter 12.7 mm, length 100 mm) filled with sodium fluoride (purity 99%, mass 30 g (0.7 mol)) as an adsorbent, and bromine trifluoride in the reaction mixture was adsorbed by the adsorbent at a temperature of 35°C. Then, the gaseous reaction mixture that passed through the stainless steel tube was supplied to a second stainless steel cooling collection vessel (capacity 500 mL) cooled to -80°C, where it was cooled, and bromine pentafluoride was collected. The composition of the collected material in the second cooling collection vessel was measured by Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy. The results are shown in Table 2.

[0104] [Table 2]

[0105] Example 2 The reaction and analysis were carried out in the same manner as in Example 1, except that bromine gas was used as the bromine-containing compound and the composition ratio (volume ratio) of the gas of the raw material compound supplied to the bright annealing tube was bromine gas: fluorine gas: nitrogen gas = 2.0: 9.0: 89.0. The results are shown in Tables 1 and 2. Example 3 The reaction and analysis were carried out in the same manner as in Example 1, except that the reaction temperature (catalyst temperature) was 150° C. The results are shown in Tables 1 and 2.

[0106] Example 4 The reaction and analysis were carried out in the same manner as in Example 1, except that the reaction temperature was 150° C. and the reaction pressure (pressure inside the bright annealing tube) was 0.2 MPa. The results are shown in Tables 1 and 2. Example 5 The reaction and analysis were carried out in the same manner as in Example 2, except that the reaction temperature was 120° C. The results are shown in Tables 1 and 2.

[0107] Example 6 The reaction and analysis were carried out in the same manner as in Example 1, except that the composition ratio (volume ratio) of the raw material compound gases supplied to the bright annealing tube was bromine trifluoride gas:fluorine gas:nitrogen gas=16.8:8.4:74.8, with F / Br being 4.0. The results are shown in Tables 1 and 2. Example 7 Except for changing the catalyst to that prepared in Catalyst Preparation Example 2 (FeF3 porous body), the reaction and analysis were carried out in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[0108] Example 8 Except for changing the catalyst to that prepared in Catalyst Preparation Example 3 (CoF2 porous body), the reaction and analysis were carried out in the same manner as in Example 1. The results are shown in Tables 1 and 2. Example 9 Except for changing the catalyst to that prepared in Catalyst Preparation Example 4 (AlF3 porous body), the reaction and analysis were carried out in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[0109] Example 10 Except for changing the catalyst to α-Al2O3, the reaction and analysis were carried out in the same manner as in Example 1. The results are shown in Tables 1 and 2. Example 11 The reaction and analysis were carried out in the same manner as in Example 1, except that bromine trifluoride and bromine gas were used as the bromine-containing compounds and the composition ratio (volume ratio) of the gas of the raw material compounds supplied to the bright annealing tube was bromine gas:bromine trifluoride gas:fluorine gas:nitrogen gas=2.0:5.6:13.2:79.2. The results are shown in Tables 1 and 2.

[0110] Example 12 The reaction and analysis were carried out in the same manner as in Example 1, except that the composition ratio (volume ratio) of the raw material compound gases supplied to the bright annealing tube was bromine trifluoride gas: fluorine gas: nitrogen gas = 25.6: 19.2: 55.2. The results are shown in Tables 1 and 2. Example 13 The reaction and analysis were carried out in the same manner as in Example 1, except that a pellet (mass 48 g (0.5 mol)) with a diameter of 3 mm and length of 5 mm, prepared by pressure molding NiF2 powder (manufactured by Aldrich, purity 99%), was used as the catalyst. The results are shown in Tables 1 and 2.

[0111] Example 14 The reaction and analysis were carried out in the same manner as in Example 1, except that the gaseous reaction mixture that had passed through the first cryogenic collection vessel was supplied to the second cryogenic collection vessel instead of being passed through the stainless steel tube filled with sodium fluoride. The results are shown in Tables 1 and 2. Example 15 The reaction and analysis were carried out in the same manner as in Example 1, except that the composition ratio (volume ratio) of the raw material compound gases supplied to the bright annealing tube was bromine trifluoride gas:fluorine gas:nitrogen gas=11.2:1.8:87.0, and F / Br was 3.3. The results are shown in Tables 1 and 2.

[0112] Example 16 The reaction and analysis were carried out in the same manner as in Example 1, except that the reaction temperature was 150° C. and the reaction pressure (pressure inside the bright annealing tube) was 0.5 MPa. The results are shown in Tables 1 and 2. Example 17 The reaction and analysis were carried out in the same manner as in Example 1, except that the reaction temperature was 400° C. The results are shown in Tables 1 and 2.

[0113] Comparative Example 1 The reaction and analysis were carried out in the same manner as in Example 1, except for the points described below. A pellet (mass 85 g (0.88 mol)) made by pressure molding NiF2 powder was used as a catalyst. The reaction temperature was 270°C. The composition ratio (volume ratio) of the raw material compound gas supplied to the bright annealing tube was bromine trifluoride gas: fluorine gas: nitrogen gas = 9.0: 45.5: 45.5. The flow rate of the raw material compound gas supplied to the bright annealing tube was set to 1151 cm at 0°C and 101 kPa so that the raw material compound gas would reside in the bright annealing tube for 10 seconds. 3 / min. No collection was performed using the first and second cold collection vessels, and no adsorption was performed using an adsorbent. The results are shown in Table 1.

[0114] In the case of Comparative Example 1, as can be seen from Table 1, the composition of the reaction mixture discharged from the bright annealing tube was 0.4 volume % of bromine trifluoride, 80.1 volume % of fluorine gas, and 19.5 volume % of bromine pentafluoride, and the reaction mixture contained a large amount of unreacted fluorine gas. Therefore, large-scale equipment is required to treat the remaining fluorine gas by recovery and detoxification.

[0115] In contrast, the results of Examples 1 and 2 show that when a NiF2 porous body is used as the catalyst and F / Br is set to 4.5, fluorine gas is quantitatively consumed and bromine pentafluoride is obtained with a purity of 99% or more, regardless of whether bromine gas or bromine trifluoride is used as the bromine-containing compound.

[0116] Furthermore, from the results of Examples 3 to 5 and Example 16, it is found that when the reaction temperature is 120° C. or 150° C., a small amount of fluorine gas remains, but the conversion rate of fluorine gas is improved by increasing the reaction pressure to 0.2 MPa or 0.5 MPa. In Examples 3 to 5, about 1% of fluorine gas was detected from the first and second cooling and collecting vessels.

[0117] The results of Examples 6 and 15 show that even if F / Br is set to 4.0 or 3.3, the reaction proceeds without any problems and bromine pentafluoride can be obtained with a purity of 99% or more. The results of Examples 7 to 10 show that when a porous FeF3 body, a porous CoF2 body, a porous AlF3 body, or α-Al2O3 is used as a catalyst, the conversion rate of fluorine gas decreases slightly, but bromine pentafluoride is obtained with high purity.

[0118] From the results of Example 11, it is seen that even under conditions in which bromine gas and bromine trifluoride gas are simultaneously passed, the conversion of fluorine gas proceeds smoothly, and bromine pentafluoride can be obtained with a purity of 99% or more. From the results of Example 12, it is seen that even if the concentration of diluting nitrogen gas is reduced to 55.2%, the conversion of fluorine gas proceeds quantitatively and bromine pentafluoride can be obtained with a purity of 99% or more.

[0119] From the results of Example 13, it is seen that when NiF2 pellets are used as a catalyst, although the conversion rate of fluorine gas decreases, bromine pentafluoride can be obtained with high purity. The results of Example 14 show that if the gaseous reaction mixture that has passed through the first cold collection vessel is not adsorbed by an adsorbent, a small amount of bromine trifluoride is collected in the second cold collection vessel. From the results of Example 17, a small amount of fluorine gas remained when the reaction temperature was 400° C. This is considered to be because the decomposition reaction of bromine pentafluoride proceeded under high temperature conditions.

[0120] Example 20 200 g of the collected material (a mixture of bromine trifluoride and bromine pentafluoride) collected in the first cooling collection vessel in Example 1 was collected. Then, except that the collected material was used as a raw material compound, that is, the collected material was used as a bromine-containing compound in the vaporizer, bromine trifluoride, fluorine gas, bromine pentafluoride, and nitrogen gas were supplied to a bright annealing tube (reactor) equipped with a catalyst, and a reaction to obtain bromine pentafluoride from fluorine gas and bromine trifluoride was continuously carried out under the reaction conditions (gas composition of raw material compound and F / Br) shown in Table 3.

[0121] [Table 3]

[0122] The composition of the reaction mixture obtained by the reaction and the compositions of the collected materials in the first and second cryogenic collection vessels are shown in Tables 3 and 4. As can be seen from Tables 3 and 4, the conversion rate of fluorine gas exceeded 99%, and bromine pentafluoride with a purity of 99% or more was collected in the second cryogenic collection vessel.

[0123] [Table 4] [Explanation of symbols]

[0124] 1. Reactor 2. Fluorine gas supply device 3, 5: Inert gas supply device 4. Carburetor 6...brominated compounds 7. First cooling collection vessel 8...Adsorption tower 9. Second cooling collection vessel 11, 12, 14 Mass flow controller 13...Heating device 15. Pressure gauge 16 Pressure Regulating Valve 17. Fourier transform infrared spectrophotometer 18...UV-visible spectrophotometer 19, 20...Cooling tank 21 Bromine trifluoride 22 Bromine pentafluoride

Claims

1. a reaction step of supplying a bromine-containing compound, which is at least one of bromine gas and bromine trifluoride, and fluorine gas into a reactor such that the molar ratio of fluorine atoms to bromine atoms, F / Br, is 3.0 or more and 4.7 or less, to react the bromine-containing compound with the fluorine gas to obtain a reaction mixture containing bromine pentafluoride and bromine trifluoride; a separation step of separating bromine pentafluoride and bromine trifluoride from the reaction mixture; having A method for producing bromine pentafluoride, wherein the reaction is carried out by placing at least one of a metal oxide and a metal fluoride as a catalyst in the reactor, the catalyst being at least one selected from the group consisting of Al2O3, FeF3, CoF2, and AlF3.

2. 2. The method for producing bromine pentafluoride according to claim 1, wherein in the reaction step, an inert gas is supplied into the reactor together with the bromine-containing compound and the fluorine gas to carry out the reaction, and an amount of the inert gas supplied is 50% by volume or more of a total volume of the gases including the bromine-containing compound, the fluorine gas, and the inert gas.

3. The method for producing bromine pentafluoride according to claim 1 or 2, wherein the reaction is carried out under a pressure of 0.1 MPa or more and 0.5 MPa or less.

4. The method for producing bromine pentafluoride according to any one of claims 1 to 3, wherein the reaction is carried out at a temperature of 100°C or higher and 400°C or lower.

5. The method for producing bromine pentafluoride according to any one of claims 1 to 4, wherein the reactor is a nickel bright annealing tube.

6. The method for producing bromine pentafluoride according to any one of claims 1 to 5, wherein the separation step includes a cooling step of cooling the reaction mixture to separate it into a gas component containing bromine pentafluoride and a liquid solid component containing bromine trifluoride.

7. 7. The method for producing bromine pentafluoride according to claim 6, wherein the separation step further comprises an adsorption step of contacting the gas component containing bromine pentafluoride obtained by the cooling step with an adsorbent to adsorb bromine trifluoride contained in the gas component containing bromine pentafluoride onto the adsorbent.

8. 8. The method for producing bromine pentafluoride according to claim 7, wherein the adsorbent is a fluoride of at least one metal selected from the group 1 and group 2 elements of the periodic table.

9. The adsorbent is LiF, NaF, KF, RbF, CsF, MgF 2 , and CaF 2 The method for producing bromine pentafluoride according to claim 7, wherein the compound is at least one selected from the group consisting of:

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