Production method for phosphorus trifluoride

Abstract

The purpose of the present invention is to provide a production method for phosphorus trifluoride in which the reaction can be carried out using readily available materials at a temperature equal to or lower than atmospheric temperature, said method being suitable for use on an industrial scale.　The production method for phosphorus trifluoride involves reacting phosphorus trichloride and hydrogen fluoride in the presence of an organic solvent.

Description

Method for producing phosphorus trifluoride

[0001] The present invention relates to a method for producing phosphorus trifluoride.

[0002] Phosphorus trifluoride (PF ３ ) is a transition metal ligand, LIB electrolyte LiPF ６ It is used as a raw material for semiconductor etching gases, etc. Phosphorus trifluoride can be produced by phosphorus trichloride (PCl ３ ) to trialkyltin fluoride (R ３ a method of reacting with a fluorinating agent such as SnF (Non-Patent Document 1), a method of reacting with phosphorus trichloride (PCl ３ ) together with hydrogen fluoride (HF) in an activated carbon packed column (Patent Document 1), ３ ) and antimony fluoride (SbF ３ ), a method of reacting phosphorus trichloride (PCl) (Non-Patent Documents 2 and 3), ３ and a method of reacting a fluoride compound (e.g., NaF or KF-HF) with an alkali metal fluoride (e.g., NaF, KF-HF) (Non-Patent Documents 4 and 5).

[0003] International Publication No. 2023 / 168597

[0004] Z. Naturforsch. 49b, 981-982 (1994)Inorganic Syntheses, 26, 12-17, 1989Inorganic Syntheses, 26, 310-15, 1990Indian Journal of Chemistry, Section A : Inorganic, Physical, Theoretical & Analytical 20A, 1, 83-84, 1981Indian Journal of Chemistry, Section A : Inorganic, Physical, Theoretical & Analytical 23A, 12, 990-991, 1984

[0005] However, PCl ３The reaction between fluorination and HF has low reactivity, requires heating at 100°C or higher and an excess amount of hydrogen fluoride, and requires time and effort to maintain the equipment and recover the raw materials. ３ Although the fluorination of phosphorus trifluoride (SnF) has been reported in Non-Patent Document 1, the fluorinating agent is expensive and difficult to use on an industrial scale. Therefore, an object of the present invention is to provide a method for producing phosphorus trifluoride that is suitable for industrial scale operation and that can carry out the reaction at a low temperature below room temperature using readily available materials.

[0006] The present invention provides the following inventions. [1] A method for producing phosphorus trifluoride, comprising reacting phosphorus trichloride with hydrogen fluoride in the presence of an organic solvent. [2] The method according to [1], wherein the organic solvent is at least one selected from the group consisting of carbonate compounds, ester compounds, ether compounds, nitrile compounds, aldehyde compounds, and ketone compounds. [3] The method according to [1], wherein the organic solvent is at least one selected from the group consisting of dimethyl carbonate, ethyl methyl carbonate, ethyl acetate, acetonitrile, tetrahydrofuran, N-methylpyrrolidone, and N,N'-dimethylpropylene urea. [4] The method according to any one of [1] to [3], wherein the reaction is carried out at a temperature of 25°C to -40°C. [5] The method according to any one of [1] to [3], further comprising removing hydrogen chloride remaining in the organic solvent from the organic solvent after the reaction, and then adding phosphorus trichloride and hydrogen fluoride to the organic solvent to continue the reaction.

[0007] According to the present invention, by using hydrogen fluoride as a fluorinating agent in the presence of an organic solvent, the reaction proceeds instantaneously at room temperature, and phosphorus trifluoride can be obtained in high yield by using an almost stoichiometric amount of hydrogen fluoride. More specifically, the present invention provides the following effects: (1) The method for producing PCl in the presence of an organic solvent according to the present invention ３ According to the reaction of PF with hydrogen fluoride, PF can be produced with almost the theoretical amount of hydrogen fluoride at temperatures below room temperature. ３Since the reaction can proceed at room temperature, in a short time, and with a theoretical amount of hydrogen fluoride, the method of the present invention can be carried out with simpler production equipment and is highly productive. (2) PF produced as a result of the reaction ３ Since HCl is a gas at room temperature and pressure, the organic solvent can be reused by expelling the product from the reaction system as a gas, resulting in a clean reaction system with little waste.

[0008] [Action] Phosphorus trichloride, the raw material, has an unshared electron pair and is therefore not expected to easily react with nucleophilic species. In fact, prior art techniques using hydrogen fluoride are generally carried out under heated conditions. On the other hand, selecting a fluorinating agent with stronger nucleophilicity increases costs and makes handling difficult. Therefore, the present inventors focused on the leaving group side of phosphorus trichloride and hypothesized that the reaction might proceed smoothly by creating an environment in which hydrogen chloride is easily eliminated. In the present invention, hydrogen fluoride was dissolved in an organic solvent, such as a carbonate compound, an ester compound, an ether compound, a nitrile compound, an aldehyde compound, or a ketone compound, which readily dissolves the hydrogen chloride by-product eliminated during the reaction, and this was used as the fluorinating agent. As a result, the reaction proceeded in a short time at or below room temperature, and phosphorus trifluoride was obtained in high yield. As will be seen from the comparative examples described below, simply stirring and mixing phosphorus trichloride and hydrogen fluoride at or below room temperature results in the mixture separating into two layers, making it impossible to efficiently fluorinate phosphorus trichloride to phosphorus trifluoride.

[0009] [Raw Material] In the present invention, phosphorus trichloride (PCl) is used as the raw material. ３ ) is used. ３ is the cheapest and most readily available trivalent phosphorus source, is liquid at room temperature, and is easier to handle than elemental phosphorus.

[0010] [Organic Solvent] The organic solvent may be any organic solvent commonly used in organic synthesis reactions, as long as it provides a good yield of the target product, phosphorus trifluoride. Examples of the organic solvent include aprotic organic solvents such as carbonate compounds, ester compounds, ether compounds, nitrile compounds, aldehyde compounds, and ketone compounds. More specifically, examples of carbonate compounds include dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and propylene carbonate (PC). Examples of ester compounds include ethyl acetate, butyl acetate, and 4-butyrolactone. Examples of ether compounds include tetrahydrofuran (THF), diethyl ether, diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether. Examples of nitrile compounds include acetonitrile and propionitrile. Examples of aldehyde compounds include butyraldehyde, benzaldehyde, phenylacetaldehyde, and tolualdehyde. Examples of ketone compounds include dimethyl ketone, methyl ethyl ketone, diethyl ketone, dibutyl ketone, methyl isobutyl ketone, cyclohexanone, acetophenone, etc. In addition, N-methylpyrrolidone, N,N'-dimethylpropylene urea, dimethyl sulfoxide, dimethylformamide, etc. can also be preferably used.

[0011] The organic solvent is PCl ３ Solvent-nHF (n is the molar ratio number) is charged into the reactor so that there is 3 times the molar amount of HF relative to the solvent. HF does not dissolve (associate) in any amount in the solvent, and as n increases, HF tends to volatilize and become difficult to handle. When n reaches the latter half of 2, HF volatilizes in solvent-nHF, generating pressure inside the reactor. The organic solvent is usually used in a volume ratio of 1 to 10 times the volume of HF.

[0012] The reaction can be carried out efficiently by mixing an organic solvent and hydrogen fluoride in advance and then adding phosphorus trichloride to the resulting mixture. The mixing ratio of the organic solvent to hydrogen fluoride is preferably 1:0.1 to 1:5 in molar ratio, more preferably 1:0.1 to 1:3 in molar ratio, more preferably 1:0.1 to 1:2.5 in molar ratio, and particularly preferably 1:0.2 to 1:2.3 in molar ratio. Specific examples of mixtures of organic solvents and hydrogen fluoride include the following: DMC-0.8HF: A mixture of dimethyl carbonate and hydrogen fluoride in a molar ratio of 1:0.8 DMC-2.3HF: A mixture of dimethyl carbonate and hydrogen fluoride in a molar ratio of 1:2.3 EMC-0.9HF: A mixture of ethyl methyl carbonate and hydrogen fluoride in a molar ratio of 1:0.9 Ethyl acetate-0.9HF: A mixture of ethyl acetate and hydrogen fluoride in a molar ratio of 1:0.9 Acetonitrile-0.4HF: A mixture of acetonitrile and hydrogen fluoride in a molar ratio of 1:0.4 THF-0.5HF: A mixture of tetrahydrofuran and hydrogen fluoride in a molar ratio of 1:0.5 NMP-0.2HF: A mixture of N-methylpyrrolidone and hydrogen fluoride in a molar ratio of 1:0.2 DMPU-1.0HF: A mixture of N,N'-dimethylpropylene urea and hydrogen fluoride in a molar ratio of 1:1.0

[0013] [Reaction Conditions] The reaction of the present invention can be carried out under atmospheric pressure at a temperature equal to or lower than room temperature. Because the produced phosphorus trifluoride and hydrogen chloride are gases under the reaction conditions, the reaction temperature is preferably around 0°C, for example, 25°C to -40°C, preferably 20°C to -20°C, more preferably 10°C to -10°C, more preferably 5°C to -5°C, and more preferably 5°C to 0°C. It is desirable that the reaction liquid be a homogeneous solution in terms of evaporation of the reaction product gas and recovery by cooling.

[0014] [Recovery of Reaction Products] In the present invention, phosphorus trifluoride and hydrogen chloride are generated as gases, which are liquefied using a condenser installed in the reactor and recovered as a mixture of phosphorus trifluoride and hydrogen chloride. The recovered mixture of phosphorus trifluoride and hydrogen chloride can be purified by precision distillation due to the difference in boiling points. The mixture ratio of phosphorus trifluoride and hydrogen chloride recovered as a gas outside the reaction system is affected by the proportion of hydrogen fluoride in the organic solvent-hydrogen fluoride mixture used in the reaction. The smaller the n number in the solvent-nHF system, the greater the solvent ratio, which tends to dissolve the by-product HCl better. For example, Example 1, described below, uses an acidic organic solvent, DMC-0.8HF, and the amount of DMC is 125.7 g, with dissolved hydrogen chloride being approximately half the theoretical amount. In contrast, Example 3, which uses DMC-2.3HF, uses 43.8 g of DMC, with dissolved hydrogen chloride being approximately 10% of the theoretical amount.

[0015] [Reuse of Organic Solvent] In the present invention, the organic solvent remains in the reactor without reacting, and after the reaction, the hydrogen chloride remaining in the organic solvent can be removed as a gas and reused in the reaction. Since the boiling point of hydrogen chloride is -85°C, which is significantly lower than that of the organic solvent, it can be easily removed by raising the temperature of the organic solvent. After removing the hydrogen chloride, hydrogen fluoride and phosphorus trichloride can be introduced back into the organic solvent, allowing phosphorus trifluoride to be repeatedly produced.

[0016] The present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to these examples. In the following description, the following abbreviations may be used. PFA: Perfluoroalkoxyalkane DMC: Dimethyl carbonate EMC: Ethyl methyl carbonate THF: Tetrahydrofuran NMP: N-methylpyrrolidone DMPU: N,N'-dimethylpropylene urea DMC-0.8HF: Mixture of dimethyl carbonate and hydrogen fluoride in a molar ratio of 1:0.8 DMC-2.3HF: Mixture of dimethyl carbonate and hydrogen fluoride in a molar ratio of 1:2.3 EMC-0.9HF: Mixture of ethyl methyl carbonate and hydrogen fluoride in a molar ratio of 1:0.9 Ethyl acetate-0.9HF: Mixture of ethyl acetate and hydrogen fluoride in a molar ratio of 1:0.9 Acetonitrile-0.4HF: Mixture of acetonitrile and hydrogen fluoride in a molar ratio of 1:0.4 THF-0.5HF: Mixture of tetrahydrofuran and hydrogen fluoride in a molar ratio of 1:0.5 NMP-0.2HF: A mixture of N-methylpyrrolidone and hydrogen fluoride in a molar ratio of 1:0.2 DMPU-1.0HF: A mixture of N,N'-dimethylpropylene urea and hydrogen fluoride in a molar ratio of 1:1.0

[0017] Example 1 A 250 ml PFA reactor, which had been thoroughly purged with dry nitrogen in advance, was equipped with a thermometer, a −5° C. chiller circulation condenser, and an inlet tube, and 147.9 g of an acidic organic solvent, DMC-0.8HF (HF content: 1.11 mol), was charged and cooled to 5° C. in an ice bath. ３ 50.0 g (0.36 mol) of the mixture was added dropwise from the introduction tube over 1 hour. Simultaneously with the addition, the generation of gas was visually confirmed. After the addition was completed, the ice bath was removed, and the reaction solution was stirred and aged for 1 hour while returning to room temperature. 38.4 g of the generated gas was collected in a SUS cylinder cooled with pentane / liquid nitrogen via a trap cooled to around -100°C. The composition of the collected gas was determined from the area % of GC analysis to be PF ３ NMR analysis of the reaction mixture revealed that PF ３ is dissolved at 3%, and the raw material PCl ３ No traces of HCl were detected. In addition, ion chromatography revealed that approximately half of the theoretical amount of HCl was dissolved. The collected gas was subjected to a standard distillation procedure, resulting in a 98% increase in the PF product.３ 27.2 g of the compound was obtained (27.2 g x 0.98 = 26.7 g, the reaction yield was 83% from 0.30 mol).

[0018] (Example 2) After HCl was removed from the reaction solution of Example 1, HF was added to re-prepare the acidic organic solvent DMC-0.8HF. Using this re-prepared acidic organic solvent, the same operation as in Example 1 was carried out, and 39.0 g of the generated gas was collected in an SUS cylinder. The composition of the collected gas was determined from the area % of GC analysis to be PF ３ NMR analysis of the reaction mixture revealed that PF ３ is dissolved at 2% and the raw material PCl ３ Furthermore, ion chromatography revealed that approximately half of the theoretical amount of HCl was dissolved.

[0019] (Example 3) The same procedure as in Example 1 was carried out, except that the acidic organic solvent was changed to 66.0 g of DMC-2.3HF (HF content: 1.11 mol). 55.0 g of the generated gas was collected in an SUS cylinder. The composition of the collected gas was determined from the area percentage of GC analysis to determine the PF ３ NMR analysis of the reaction mixture revealed that PF ３ is dissolved at 1% and the raw material PCl ３ Furthermore, ion chromatography revealed that approximately 10% of the theoretical amount of HCl was dissolved.

[0020] Example 4 A 250 ml PFA reactor, which had been thoroughly purged with dry nitrogen in advance, was equipped with a thermometer, a −5° C. chiller circulation condenser, and an inlet tube, and 66.0 g of an acidic organic solvent, DMC-2.3HF (HF content: 1.11 mol), was charged and the internal temperature was adjusted to 25° C. While stirring, PC1 ３ 50.0 g (0.36 mol) of the mixture was added dropwise from the introduction tube over 1 hour. The generation of gas was visually confirmed at the same time as the addition, and the mixture was stirred and aged for 1 hour after the addition. 58.5 g of the generated gas was collected in a SUS cylinder cooled with pentane / liquid nitrogen via a trap cooled to around -100°C. The composition of the collected gas was determined from the area % of GC analysis to be PF ３ NMR analysis of the reaction mixture revealed that PF ３is dissolved at 1% and the raw material PCl ３ Furthermore, ion chromatography revealed that approximately 7% of the theoretical amount of HCl was dissolved.

[0021] (Example 5) A 100 ml PFA reactor, which had been thoroughly purged with dry nitrogen in advance, was equipped with a thermometer, a −5° C. chiller circulation condenser, and an inlet tube, and 30 ml of the solvent DMC and PC1 ３ The mixture was cooled to 5°C in an ice bath. While stirring, 6.6 g (0.33 mol) of HF was introduced over 1 hour. The evolved gas was monitored by FT-IR. ３ Only PCl and HCl were detected. NMR analysis of the reaction solution that had been stirred and aged for 1 hour after the introduction of HF revealed that PCl ３ Thus, even if the order of adding the solvents is changed, PF ３ It was confirmed that this occurs.

[0022] Example 6 The same procedure as in Example 1 was carried out, except that the acidic organic solvent was changed to 151.3 g of EMC-0.9HF (HF content: 1.11 mol). 38.1 g of the gas generated by the reaction was collected in an SUS cylinder. The composition of the collected gas was determined from the area % of GC analysis to be PF ３ NMR analysis of the reaction mixture revealed that PF ３ is dissolved at 2% and the raw material PCl ３ Furthermore, ion chromatography revealed that approximately half of the theoretical amount of HCl was dissolved.

[0023] (Example 7) The same procedure as in Example 6 was carried out except that the reaction temperature was changed to -20°C. 34.9 g of the gas generated in the reaction was collected in an SUS cylinder. The composition of the collected gas was determined from the area % of GC analysis to be PF ３ NMR analysis of the reaction solution revealed that PF ３ is dissolved at 3%, and the raw material PCl ３ Furthermore, ion chromatography revealed that approximately 70% of the theoretical amount of HCl dissolved.

[0024] Example 8 The same procedure as in Example 1 was carried out, except that the acidic organic solvent was changed to 131.4 g of ethyl acetate-0.9HF (HF content: 1.11 mol). 41.0 g of the gas generated by the reaction was collected in an SUS cylinder. The composition of the collected gas was determined from the area percentage of GC analysis to be PF ３ NMR analysis of the reaction mixture revealed that PF ３ is dissolved at 3%, and the raw material PCl ３ Furthermore, ion chromatography revealed that approximately half of the theoretical amount of HCl was dissolved.

[0025] (Example 9) The same procedure as in Example 1 was carried out, except that the acidic organic solvent was changed to 136.7 g of acetonitrile-0.4HF (HF content: 1.11 mol). 38.7 g of the gas generated by the reaction was collected in an SUS cylinder. The composition of the collected gas was determined from the area % of GC analysis to be PF ３ NMR analysis of the reaction mixture revealed that PF ３ is dissolved at 1% and the raw material PCl ３ Furthermore, ion chromatography revealed that approximately 60% of the theoretical amount of HCl dissolved.

[0026] (Example 10) The same procedure as in Example 1 was carried out, except that the acidic organic solvent was changed to 183.0 g of THF-0.5HF (HF content: 1.11 mol). 36.8 g of the gas generated by the reaction was collected in an SUS cylinder. The composition of the collected gas was determined from the area percentage of GC analysis to be PF ３ NMR analysis of the reaction mixture revealed that the raw material PCl ３ was not detected, and PF ３ The dissolved amount of HCl was confirmed to be 1%. Furthermore, ion chromatography showed that the amount of dissolved HCl was approximately half of the theoretical amount.

[0027] (Example 11) The acidic organic solvent was NMP-0.2HF 143.8 g (HF content 0.28 mol), PCl ３ The same procedure as in Example 1 was carried out except that the amount of the reaction mixture was changed to 12.5 g (0.09 mol). 6.0 g of the gas generated by the reaction was collected in an SUS cylinder. The composition of the collected gas was determined by area % of GC analysis. ３NMR analysis of the reaction mixture revealed that the raw material PCl ３ was not detected, and PF ３ A 10% solution was confirmed, and several by-products were confirmed. A white solid was visually confirmed in the reaction solution.

[0028] (Example 12) The acidic organic solvent was 41.3 g of DMPU-1.0HF (HF content: 0.28 mol), PCl ３ The same procedure as in Example 1 was carried out except that the amount of the reaction mixture was changed to 12.5 g (0.09 mol). 5.6 g of the gas generated by the reaction was collected in an SUS cylinder. The composition of the collected gas was determined from the area percentage of PF ３ NMR analysis of the reaction mixture revealed that the raw material PCl ３ was not detected, and PF ３ 10% dissolved, and several by-products similar to those in Example 9 were confirmed.

[0029] (Comparative Example 1) A 50 ml PFA reactor, which had been thoroughly purged with dry nitrogen in advance, was equipped with a thermometer, a −5° C. chiller circulation condenser, and an inlet tube. ３ The reaction mixture was cooled to 5°C in an ice bath. 2.2 g (110 mmol) of HF was added while stirring. No gas generation was visually confirmed, and the reaction mixture was stirred and aged for 1 hour after the HF introduction. The reaction mixture separated into two layers. NMR analysis revealed that the upper layer was unreacted PCl ３ The lower layer is unreacted HF, and the lower layer is PF ３ was not generated.

[0030] As can be seen from the above examples, the method of the present invention allows the reaction to be carried out at low temperatures below room temperature using readily available materials, with a reaction yield exceeding 80%, making it suitable for producing phosphorus trifluoride on an industrial scale. Comparative Example 1 demonstrated that simply mixing phosphorus trichloride and hydrogen fluoride at temperatures below room temperature does not result in a reaction. The results of Example 4 (reaction temperature 25°C) and Example 7 (reaction temperature -20°C) demonstrated that a high reaction temperature tends to decrease the amount of dissolved hydrogen chloride (7%) and increase the proportion of hydrogen chloride in the product gas (48%), while a low reaction temperature tends to increase the amount of dissolved hydrogen chloride (70%) and decrease the proportion of hydrogen chloride in the product gas (10%). Example 5 demonstrated that changing the order of solvent addition did not result in the production of PF ３ It was confirmed that this occurs.

Claims

1. A method for producing phosphorus trifluoride, which comprises reacting phosphorus trichloride with hydrogen fluoride in the presence of an organic solvent.

2. The method according to claim 1, wherein the organic solvent is at least one selected from the group consisting of carbonate compounds, ester compounds, ether compounds, nitrile compounds, aldehyde compounds, and ketone compounds.

3. The method according to claim 1, wherein the organic solvent is at least one selected from the group consisting of dimethyl carbonate, ethyl methyl carbonate, ethyl acetate, acetonitrile, tetrahydrofuran, N-methylpyrrolidone, and N,N'-dimethylpropylene urea.

4. The method according to any one of claims 1 to 3, wherein the reaction is carried out at a temperature of 25°C to -40°C.

5. The method according to any one of claims 1 to 3, further comprising removing hydrogen chloride remaining in the organic solvent from the organic solvent after the reaction, and then adding phosphorus trichloride and hydrogen fluoride to the organic solvent to continue the reaction.

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