JP5036990B2 - Method for producing manganese fluoride - Google Patents

Description

  The present invention relates to a method for producing manganese fluoride excellent in safety and productivity.

  In recent years, fluorine gas has been used for the etching process and the cleaning process in the electronic industry field, and has been used for the fluorination of inorganic compounds and organic compounds, taking advantage of its characteristics. However, since fluorine gas is a combustion-supporting gas with very strong oxidizing properties, and it is highly toxic and corrosive, it must be handled with care and difficult to be purified by distillation when producing fluorine gas. It has been known.

As a method for safely supplying fluorine gas, HALOGEN GENERATOR that generates fluorine gas by heating a fluorine compound has been proposed (see, for example, Patent Document 1).
Patent Document 2 discloses a method for producing purified fluorine gas using MnF ₄ . Specifically, first, MnF ₄ produced by reacting MnF ₃ and fluorine gas in a fluorine gas stream at 450 to 650 ° C. was sublimated and then condensed at a temperature of 70 ° C. or less.
A method is described in which high purity fluorine gas is obtained by heating nF ₄ to 70 to 300 ° C. according to a reaction formula of MnF ₄ → MnF ₃ + 1 / 2F ₂ .

However, in this method, MnF ₄ cannot be synthesized unless it is a complicated apparatus that can perform heating sublimation and collection of sublimated MnF ₄ , and it has to go through a process of sublimation and condensation. There is a problem that production is difficult.

In order to produce MnF ₄ without going through a process of sublimation / condensation, the present inventors
A method of synthesizing MnF ₄ via MnF ₃ by reacting MnF ₂ with fluorine gas (
As a reaction formula, MnF ₂ + F ₂ → MnF ₄ ) was tried. However, simply reacting MnF ₂ with fluorine gas makes it vitreous and melts it into a glass, making it difficult to produce MnF ₄ . When the pressure is increased, the reaction to MnF ₄ proceeds, but a pressure vessel that can use fluorine gas at a high temperature and a high pressure becomes very expensive, and as a result, the synthesized MnF ₄ becomes expensive. Therefore, there has been a demand for the development of a method capable of performing the reaction at as low a temperature and low pressure as possible.
US 5,363,396 SU143001

  An object of the present invention is to develop a method for producing a large amount of manganese fluoride capable of generating fluorine gas under low temperature and low pressure conditions and a simple method without going through a process of sublimation and condensation. .

The present inventors have intensively studied to solve the above problems. As a result, when producing manganese fluoride (MnF _x : x = 3-4) by reacting a manganese compound with a fluorinating agent, 5
After performing the step (1) of bringing the fluorinating agent into contact with the manganese compound at a temperature of 0 to 250 ° C., the method of contacting the fluorinating agent at 250 to 450 ° C. with the manganese fluoride passed through the step (1), It has been found that the above problems can be solved, and the present invention has been completed.

That is, this invention relates to the manufacturing method of manganese fluoride shown by the following [1]-[11].
[1] Step (1) of reacting a manganese compound and a fluorinating agent at 50 to 250 ° C., and further reacting the product obtained in the step (1) with the fluorinating agent at 250 to 450 ° C. The manufacturing method of manganese fluoride characterized by including a process (2).

[2] The method for producing manganese fluoride according to [1], including a step of drying the manganese compound at a temperature of 100 ° C. or higher before the step (1).
[3] The step (1) includes a step of contacting the manganese compound and the fluorinating agent by supplying the fluorinating agent to the container filled with the manganese compound at a constant rate from the reduced pressure state until a constant pressure is reached. The method for producing manganese fluoride according to [1] or [2].

  [4] The step (2) includes a step of contacting the manganese compound and the fluorinating agent by supplying the fluorinating agent to the container filled with the manganese compound at a constant rate from the reduced pressure state to a constant pressure. [1] The method for producing manganese fluoride according to any one of [3].

[5] The method for producing manganese fluoride according to any one of [1] to [4], wherein the step (1) includes a step of removing impurities under reduced pressure.
[6] The method for producing manganese fluoride according to any one of [1] to [5], wherein the step (2) includes a step of removing impurities under reduced pressure.

[7] The manganese compound, MnF _2, MnCO _3, MnO and manganese fluoride as claimed in any one of at least one compound selected from the group consisting of hydrate [1] to [6] Manufacturing method.

[8] The method for producing manganese fluoride according to [7], wherein the manganese compound is MnF ₂ or a hydrate thereof.
[9] The method for producing manganese fluoride according to any one of [1] to [8], wherein the fluorinating agent is at least one compound selected from the group consisting of F ₂ , ClF, and ClF ₃ .

Method for producing manganese fluoride as claimed in [10] wherein the fluorinating agent is F ₂ [9].
[11] The method for producing manganese fluoride according to any one of [1] to [10], wherein the manganese fluoride obtained by the production method is MnF _x (x = 3 to 4).

[12] The method for producing manganese fluoride according to any one of [1] to [11], wherein the reaction in the step (1) is performed at 100 to 200 ° C.
[13] The method for producing manganese fluoride according to any one of [1] to [12], wherein the reaction in the step (2) is performed at 250 to 400 ° C.

  [14] The method for producing manganese fluoride according to any one of [1] to [13], wherein the reaction in the steps (1) and (2) is performed while pulverizing the reaction product.

  According to the present invention, the reaction between the manganese compound and the fluorinating agent can be performed under conditions of low temperature and low pressure, and manganese fluoride can be produced in a large amount by an inexpensive and simple method without going through a process of sublimation and condensation. Can be manufactured.

Hereinafter, the manufacturing method of manganese fluoride concerning the present invention is explained in detail.
The method for producing manganese fluoride according to the present invention comprises the step (1) of reacting a manganese compound with a fluorinating agent brought into contact at a temperature of 50 to 250 ° C., and then the product obtained by the step (1). And a step (2) in which a fluorinating agent is brought into contact with and reacted at a temperature of 250 to 450 ° C.

As the manganese compound used in the present invention, a commercially available manganese compound can be used, and examples thereof include MnF ₂ , MnCO ₃ , and MnO. Among these, it is preferable to use MnF ₂ because it is not necessary to replace the anion with fluorine.

The manganese compound may be a hydrate, but the by-product HF generated by the reaction with fluorine gas may inhibit the synthesis of manganese fluoride, so that it is preferably 100 ° C. or higher, more preferably 200 ° C. or higher, It is particularly preferable that the drying be performed at a temperature of 300 ° C. or higher before contacting with the fluorinating agent. Examples of the drying method include a method of drying under an inert gas (He, N _2, etc.) stream having a dew point of −70 ° C. or less, a method of heating under reduced pressure conditions, and the like.

The fluorinating agent used in the present invention may be any fluorinating agent that can increase the valence of manganese, and examples thereof include F ₂ , ClF, and ClF ₃ . Among these, it is preferable to use F ₂ because only pure fluorination can proceed.

Next, a method for producing manganese fluoride using MnF ₂ as a manganese compound and F ₂ as a fluorinating agent will be specifically described.
In addition, since manganese fluoride does not exist as a single molecule, the crystal structure is in a state where a MnF ₃ state and a MnF ₄ state are mixed. Therefore, for example, when the MnF ₃ state is 50% and the MnF ₄ state is 50% in the crystal structure, it is expressed as MnF _{3.5 in} this specification. In this way, the valence is not expressed as an integer but may be expressed as a number including a decimal point. Therefore, in this specification, it is expressed as MnF _x (x = 3 to 4).

The purity of MnF _{2 to be} used is not particularly limited, but if the purity is too low, fluorination may be inhibited by impurities. Therefore, it is preferably 90% or more, more preferably 95% or more, and particularly preferably 98% or more. It is desirable to be. Further, the purity of F ₂ is not particularly limited, but as with MnF ₂ , fluorination may be inhibited by impurities if the purity is too low, and is preferably 95% or more, more preferably 99% or more, particularly Preferably it is 99.9% or more. In addition, when HF is present in F ₂ , a molten salt of manganese fluoride is likely to be generated. Therefore, the HF concentration in F ₂ is preferably 1% or less, more preferably 0.1%.
% Or less, particularly preferably 0.01% or less.

The average particle diameter of MnF ₂ is preferably 10 μm or less, more preferably 1 μm or less, and particularly preferably 0.1 μm or less, because the smaller the particle size, the larger the surface area and the better the efficiency of fluorination. Is desirable.

Further, MnF ₂ is usually a reaction of MnCO ₃ and HF (MnCO ₃ + 2HF →
MnF ₂ + CO ₂ + H ₂ O). By using such anhydrous MnF ₂ , manganese fluoride (MnF _x : x = 3 to 4) can be produced without going through a process such as sublimation / condensation. This method is preferable because it can be manufactured at a lower cost than the method.

In the method for producing manganese fluoride of the present invention, first, the above MnF ₂ is put in a reaction vessel, and initial drying is performed while heating under reduced pressure. This trace amount of or crystal water remaining in the preparation of MnF _2, in order to remove moisture adhering to MnF ₂ crystal surface. At this time, the depressurization is interrupted, and after pressurizing the reaction vessel with an inert gas (He, N _2, etc.) having a dew point of −70 ° C. or lower, the depressurized state is again applied to efficiently remove moisture. it can. If the number of times is increased, the water can be removed as much, but the water can be sufficiently removed by repeating the operation 5 to 10 times. If the temperature at this time is 100 ° C. or higher, the water can be removed, but it is preferable to carry out at 300 to 400 ° C. because the water can be removed more efficiently.

After removing moisture of MnF ₂ as described above, when reacting with F ₂ to synthesize manganese fluoride, first the reaction vessel is evacuated (<1 kPa) and then F ₂ is introduced into the reaction vessel. . At this time, if fluorine gas is supplied into the reaction vessel at a pressure and the pressure is higher than atmospheric pressure, the reaction between MnF ₂ and F ₂ proceeds instantaneously and the manganese compound melts and solidifies, and the solidified internal fluoride Since F ₂ cannot contact manganese and the reaction does not proceed, the reaction rate may be greatly reduced. Therefore, melting is prevented and fluorination can be continued by slowly supplying a flow rate of F ₂ to the reaction vessel in a vacuum state.

The reaction between MnF ₂ and F ₂ in the step (1) is desirably performed at 50 to 250 ° C., more preferably at 100 to 200 ° C. If the reaction temperature in step (1) is too low, the reaction rate will be slow, and if it is too high, MnF ₄ may be produced on the crystal surface and the reaction may not proceed further.

The rate of F ₂ supplied to the vacuum vessel at the above reaction temperature is preferably 1 mol / hr or less, more preferably 0.5 mol / hr or less, particularly preferably 0.1 mol with respect to 1 mol of the manganese compound inside the reaction vessel. / Hr or less is desirable. At the beginning of the reaction, MnF ₂
Since the reaction rate of F ₂ and F ₂ is slower than the supply rate of F ₂ , the pressure in the reaction vessel gradually increases, and when the pressure becomes equal to the supply pressure, the reaction vessel has a constant pressure. In the latter stage of the reaction when the pressure is constant, only F ₂ reacts with manganese fluoride. Until it reaches a certain pressure,
The supply rate of F ₂ is preferably constant within the above range.

  The pressure of fluorination in the above step (1) is not particularly limited, but if it is carried out at a high pressure, the risk of handling fluorine gas increases, and an expensive pressure-resistant reaction vessel is required. Is preferred. The specific pressure is preferably 2 MPa or less, more preferably 1 MPa or less, and particularly preferably 0.5 MPa or less.

As described above, the reason why the manganese fluoride can be prevented from being melted by controlling the supply rate of F ₂ is not clearly understood. However, if it is suddenly supplied, it may be instantaneously generated on the surface of the MnF ₂ crystal. It is presumed that MnF ₄ is formed, and MnF ₄ is melted by the heat of reaction at that time and is adhered and solidified.

When synthesizing manganese fluoride in the above step (1), fluorination is performed using MnF ₂ that has been dried first. Depending on the purity of MnF ₂ , impurities may be present in the form of Mn—OH or the like even after drying. There is a possibility that F ₂ and impurities react to generate impurities such as HF. Therefore, it is desirable to remove these impurities by temporarily stopping the supply of F _{2 during} the reaction and reducing the pressure. The number of times of depressurization at this time depends on the amount of impurities to be generated, but may be approximately once, and may be two or more depending on the amount of impurities to be generated.

If the reaction in the above step (1) is continued, absorption of fluorine gas into manganese fluoride in the reaction vessel stops, and the reaction does not proceed any further. At this time, the analysis of the synthesized through the steps (1) manganese fluoride, because it is MnF _x (x ≒ 3), from MnF _2, approximately MnF ₃
The resulting compound has been synthesized. Even if the step (1) is continued, MnF ₃
Since the reaction to a further fluorinated compound hardly proceeds, step (2) is subsequently carried out.

The reaction temperature in step (2) is preferably in the range of 250 to 450 ° C, more preferably 250 to 400 ° C, in order to further promote fluorination. Thus, fluorination further proceeds by raising the reaction temperature, but MnF _x synthesized in step (1) may have x smaller than 3, but in that case, step (2) When carrying out
There is a possibility of dissolution and solidification by increasing the initial reaction heat. Therefore, in the step (2), it is preferable to raise the reaction temperature stepwise from 250 ° C.

By gradually increasing the reaction temperature as described above, absorption of fluorine gas by manganese fluoride in the reaction vessel is resumed, and the reaction is continuously performed at the same pressure as that in the later stage of the reaction in step (1). Can do. In addition, it is more preferable that the step (2) is performed after once removing the impurities that may be generated in a trace amount under a reduced pressure condition when the step (1) is completed. Further, in the step (2), in order to avoid instantaneously reacting on the surface of the manganese fluoride compound and causing the powder to be in a molten state as in the step (1), the flow rate is slowly restricted to the vacuum vessel while the flow rate is limited. It is preferable to introduce ₂ to perform fluorination.

The supply rate of F ₂ in the step (2) is preferably 1 mol / hr or less, more preferably 0.5 mol / hr or less, particularly preferably 0.1 mol with respect to 1 mol of the manganese compound inside the decompressed reaction vessel. / Hr or less is desirable. At this time, as in step (1), in the initial reaction of step (2), the reaction rate of manganese fluoride and F ₂ is slower than the supply rate of F ₂ , so that the pressure in the reaction vessel gradually increases. When the pressure becomes equal to the supply pressure, the inside of the reaction vessel becomes a constant pressure. In the later stage of the reaction when the pressure is constant, only the amount of fluorine gas that has reacted with manganese fluoride is supplied. Incidentally, until a constant pressure, it is preferable feed rate of F ₂ is constant within the above range.

  The pressure of fluorination in step (2) is not particularly limited as in step (1). However, if it is carried out at a high pressure, the risk of handling fluorine gas increases, and an expensive pressure-resistant reaction vessel is required. It is preferable to carry out at a pressure as low as possible. The specific pressure is preferably 2 MPa or less, more preferably 1 MPa or less, and particularly preferably 0.5 MPa or less.

In the step (2), since fluorination is performed under a higher temperature condition, impurities such as HF may be generated from impurities that have not reacted in the step (1). Therefore, it is desirable to remove these impurities by temporarily stopping the supply of F ₂ and reducing the pressure. The number of times of depressurization at this time depends on the amount of impurities to be generated, but may be approximately once, and may be performed twice or more depending on the amount of impurities to be generated.

Further, in step (1) and step (2), the reaction may be performed while pulverizing the reaction product.
By implementing the manufacturing method of the present invention described above, at least x = 3 to 3 from MnF _2.
4 MnF _x , more specifically x = 3.5 to preferred for use as a fluorine generator
4 MnF _x can be synthesized.

  The shape of the reaction vessel used in the present invention is not particularly limited. However, if the reaction vessel is extremely thin or thick and short, it takes a space as a reaction vessel, which is not preferable. Therefore, in the case of a cylindrical reaction vessel, the ratio between the agent filling height and the reaction vessel diameter is preferably about agent filling height / reaction vessel diameter = about 1.5-15.

Regarding the valence of manganese in this specification, manganese fluoride is dissolved in a nitric acid aqueous solution or a hydrochloric acid aqueous solution, manganese is analyzed by ICP, and fluorine is analyzed by ion chromatography. The ratio was calculated.

  High purity fluorine gas of 99,95% or more can be generated by placing manganese fluoride obtained by the production method of the present invention in a Ni container and heating. The purity of the fluorine gas can be determined by analyzing the amount of impurities contained in the fluorine gas by gas chromatography and FT-IR.

[Example]
EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not limited to these Examples at all.

FIG. 1 is a schematic view showing an example of a production apparatus used in the method for producing manganese fluoride of the present invention. The following examples and comparative examples were performed using a manufacturing apparatus as shown in FIG.
[Example 1]
60 g (0.65 mol) of MnF ₂ was charged into a 0.1 L-Ni reaction vessel 10 (φ30 × 150 mm). The reaction vessel 10 is heated by an electric heater 9 and the pressure is 1 by a vacuum pump 11.
The pressure was reduced to kPa or less and drying was performed for 1 hour. Vacuuming was temporarily interrupted in the middle of drying, He was supplied from the valve 3 to the reaction vessel 10 at 0.1 MPa (gauge pressure), and vacuuming was performed again five times. Thereafter, fluorine gas (F ₂ ) was added to the reaction vessel 10 in a vacuum state of 150 ° C. and 1 kPa or less by the mass flow controller 5 at 50 ml / min (0.13 mol).
/ Hr), and the reaction of the step (1) was performed. The pressure gradually increased and became constant at 0.4 MPa, the same as the supply pressure, and absorption of fluorine gas by manganese fluoride in the reaction vessel continued. At 360 minutes after the start of the reaction, the supply of the fluorine gas was stopped once, and the pressure inside the reaction vessel was reduced to 1 kPa or less by evacuation, and then the fluorine gas was again reduced to 50 ml / min (0.13 mol / min by the mass flow controller 5). hr). The pressure rose to 0.4 MPa, the same as the supply pressure, and absorption of fluorine gas by manganese fluoride in the reaction vessel was started again, and the reaction was terminated when absorption of fluorine gas by manganese fluoride was not observed. Changes in fluorine gas flow rate and pressure are shown in FIGS. 2 and 3, respectively. As a result of obtaining the valence of manganese fluoride obtained from the analysis values of ICP and ion chromatography, it was MnF _2.96 .

[Example 2]
Subsequent to Example 1, step (2) was performed.
First, the supply of fluorine gas was stopped, and evacuation was performed with a vacuum pump 11 to make the pressure in the reaction vessel 1 kPa or less. Thereafter, fluorine gas was supplied at 200 ml / min (0.54 mol / hr) to the reaction vessel 10 in a vacuum state of 280 ° C. and 1 kPa or less to carry out the reaction in the step (2). The reaction was terminated when no absorption of fluorine gas by manganese fluoride was observed. Changes in fluorine gas flow rate and pressure are shown in FIGS. 4 and 5, respectively. As a result of obtaining the valence of manganese fluoride obtained from the analysis values of ICP and ion chromatography, it was MnF _3.91 .

[Comparative Example 1]
60 g (0.65 mol) of MnF ₂ was charged into a 0.1 L-Ni reaction vessel 10 (φ30 × 150 mm). The reaction vessel 10 is heated by an electric heater 9 and the pressure is 1 by a vacuum pump 11.
The pressure was reduced to kPa or less and drying was performed for 1 hour. The evacuation was temporarily interrupted during the drying, and He was supplied from the valve 3 to the reaction vessel at 0.1 MPa (gauge pressure), and the evacuation was performed again 5 times. Thereafter, fluorine gas was supplied at 50 ml / min (0.13 mol / hr) by the mass flow controller 5 to the reaction vessel 10 in a vacuum state of 300 ° C. and 1 kPa or less to perform a fluorination reaction. After the start of the reaction, the pressure gradually increased and became constant at 0.4 MPa, the same as the supply pressure. At 360 minutes after the start of the reaction, the supply of fluorine gas was once stopped, vacuuming was performed to reduce the pressure in the reaction vessel to 1 kPa or less, and then the fluorine gas was reduced to 50 ml / min (0.13 mol / hr by the mass flow controller 5). ). The pressure rose to 0.4 MPa, the same as the supply pressure, and the reaction was terminated because manganese fluoride in the reaction vessel hardly absorbed the fluorine gas. Changes in the flow rate and pressure of the fluorine gas are shown in FIGS. 6 and 7, respectively. As a result of obtaining the valence of manganese fluoride obtained from the analysis values of ICP and ion chromatography, it was MnF _2.11 .

  From the above results, it was found that the fluorination reaction did not proceed sufficiently when the initial temperature of the reaction was 300 ° C. as compared with Example 1.

It is the schematic which shows an example of the manufacturing apparatus used for the manufacturing method of manganese fluoride of this invention. 3 is a graph showing changes in the flow rate of fluorine gas in Example 1. 3 is a graph showing changes in pressure in Example 1. 6 is a graph showing changes in the flow rate of fluorine gas in Example 2. 6 is a graph showing changes in pressure in Example 2. 6 is a graph showing changes in the flow rate of fluorine gas in Comparative Example 1. 10 is a graph showing changes in pressure in Comparative Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Stop valve 2 ... Pressure gauge 3 ... Stop valve 4 ... Stop valve 5 ... Mass flow controller 6 ... Cushion tank 7 ... NaF cylinder 8 ... Stop valve 9. · heater 10 ... Ni reaction vessel 11 ... vacuum pump 12 ... abatement _{13 ··· Mn x F y (y} / x = 2~4)
14 ... Thermocouple

Claims (11)

50 at least one manganese compound selected from the group consisting of MnF ₂ , MnCO ₃ , MnO and their hydrates and at least one fluorinating agent selected from the group consisting of F ₂ , ClF and ClF ₃ A step (1) of reacting at ˜250 ° C., and a product obtained by the step (1) and at least one fluorinating agent selected from the group consisting of F ₂ , ClF and ClF ₃ , The step of reacting at ~ 450 ° C (2)
Only including,
The pressure in the step (1) is 2 MPa or less, and the supply rate of the fluorinating agent is 1 mol / hr or less with respect to 1 mol of the manganese compound;
Wherein step (2) the pressure in is less than or equal 2 MPa, and, MnF _{x (x} = 3 the feed rate of the fluorinating agent is characterized <br/> that is 1mol / hr or less with respect to the manganese compound 1mol Manufacturing method of manganese fluoride represented by ~ 4) .   The manufacturing method of the manganese fluoride of Claim 1 including the process of drying the said manganese compound at the temperature of 100 degreeC or more before the said process (1).   The step (1) includes a step of supplying a fluorinating agent to a container filled with a manganese compound at a constant rate from a reduced pressure state until a constant pressure is brought into contact with the manganese compound and the fluorinating agent. Or the manufacturing method of manganese fluoride of 2.   The step (2) includes a step of contacting the manganese compound and the fluorinating agent by supplying the fluorinating agent to the container filled with the manganese compound at a constant rate from a reduced pressure state to a constant pressure. The manufacturing method of manganese fluoride in any one of -3.   The method for producing manganese fluoride according to claim 1, wherein the step (1) includes a step of removing impurities under reduced pressure.   The method for producing manganese fluoride according to any one of claims 1 to 5, wherein the step (2) includes a step of removing impurities under reduced pressure. The method for producing manganese fluoride according to claim 1, wherein the manganese compound is MnF ₂ or a hydrate thereof. Method for producing manganese fluoride as claimed in claim 1 wherein the fluorinating agent is F _2. The method for producing manganese fluoride according to any one of claims 1 to 8 , wherein the reaction in the step (1) is performed at 100 to 200 ° C. The method for producing manganese fluoride according to any one of claims 1 to 9 , wherein the reaction in the step (2) is performed at 250 to 400 ° C. The method for producing manganese fluoride according to any one of claims 1 to 10 , wherein the reaction in the steps (1) and (2) is performed while pulverizing the reaction product.

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