JP5732785B2 - Stabilized solvent solution of lithium perfluorinated inorganic acid - Google Patents

Description

  The present invention relates to a method for producing a stabilized solvent solution of a perfluorinated inorganic acid lithium salt. Stabilized solvent solution of lithium perfluorinated inorganic acid salt can be used as a raw material for obtaining unstable lithium perfluorinated inorganic acid (solid) in the atmosphere and as a transport solution for lithium perfluorinated inorganic acid . Note that lithium perfluorinated inorganic acid (for example, lithium hexafluorophosphate, lithium tetrafluoroborate, etc.) is useful, for example, as a catalyst for organic synthesis reaction, a dopant for semiconductor materials, and an electrolyte for lithium ion batteries. A compound.

  Conventionally, as a method for producing lithium perfluorinated inorganic acid, for example, lithium hexafluorophosphate, a method of reacting phosphorus pentafluoride with lithium fluoride in anhydrous hydrofluoric acid (for example, see Patent Document 1) A method of reacting potassium hexafluorophosphate with lithium chloride (for example, see Patent Document 2) is disclosed.

  In addition, as a method for producing lithium tetrafluoroborate, for example, a tetrafluoroborate and lithium carbonate are reacted in an aqueous solvent to obtain a lithium tetrafluoroborate aqueous solution, and then water is removed under reduced pressure. A method of vacuum-drying the solid obtained above at 90 to 160 ° C. (for example, see Patent Document 3) or a method of reacting lithium carbonate and boron trifluoride diethyl ether complex in diethyl ether (for example, non-patent document) 1) and the like.

JP 2000-82474 A US Pat. No. 5,378,445 Chinese Patent No. 101318664 Japanese Patent Application No. 2010-048454 J. et al. Am. Chem. Soc. , 75, 1753 (1953)

  In general, lithium perfluorinated inorganic acid is a known compound and is usually marketed as a solid reagent. However, it is extremely weak against a small amount of moisture in the atmosphere and generates hydrogen fluoride gas. It is also a compound that is complicated to handle. Therefore, in the isolation and acquisition of solid lithium perfluorinated inorganic acid, its transport, and the preparation of organic solutions, great care was required to avoid contamination with water. Furthermore, there has been no known any stabilized solvent solution of lithium perfluorinated inorganic acid obtained from the water / organic solvent mixed solution of lithium perfluorinated inorganic acid of the present invention.

  An object of the present invention is to provide a stabilized solvent solution of lithium perfluorinated inorganic acid useful as a catalyst for organic synthesis reaction, a dopant for semiconductor materials, and an electrolyte for lithium ion batteries.

  The subject of this invention is general formula (1).

(In the formula, M represents a nonmetallic element or a metallic element, and n represents an integer of 1 to 6.)
This is solved by a stabilized solvent solution of lithium perfluorinated inorganic acid obtained by dehydrating after mixing a water / organic solvent mixed solution of lithium perfluorinated inorganic acid and a stabilizing solvent shown in FIG.

  According to the present invention, it is possible to provide a stabilized solvent solution of lithium perfluorinated inorganic acid useful as a catalyst for organic synthesis reaction, a dopant for semiconductor materials, and an electrolyte of a lithium ion battery.

It is a figure which shows the XRD measurement of various lithium hexafluorophosphate addition compounds.

  The lithium perfluorinated inorganic acid of the present invention has a general formula composed of an anion obtained by perfluorinating a nonmetallic element (for example, phosphorus, boron) or a nonmetallic element (for example, arsenic, antimony) and a lithium cation. (1)

(In the formula, M represents a nonmetallic element or a metallic element, and n represents an integer of 1 to 6.)
The compound shown by these is shown.

  The nonmetallic element is preferably phosphorus or boron, and the metallic element is preferably arsenic or antimony. N represents an integer of 1 to 6.

  Specific examples of the lithium perfluorinated inorganic acid represented by the general formula (1) include, for example, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroantimonate, and hydrogen hexafluoride. Examples of the acid include lithium lithium phosphate, preferably lithium hexafluorophosphate and lithium tetrafluoroborate.

  The stabilizing solvent in the stabilizing solvent solution of lithium perfluorinated inorganic acid of the present invention refers to a solvent that suppresses decomposition of lithium perfluorinated inorganic acid during dehydration treatment.

  Examples of the stabilizing solvent include carbonates such as dimethyl carbonate, diethyl carbonate, dibutyl carbonate, methyl ethyl carbonate, ethylene carbonate, propylene carbonate, and diphenyl carbonate; carboxylic acid esters such as butyrolactone; formamide, dimethylformamide, and acetamide Amides such as N-methylpyrrolidinone; Ureas such as 1,3-dimethylimidazolidinone and 1,3-dimethyl-2,4-imidazolidine-dione; Diethyl ether, dipropyl ether, 1,2-dimethoxy Methane, 1,2-diethoxyethane, tetrahydropyran, tetrahydrofuran, ethylene oxide, propylene oxide, 1,4-dioxane, 1,3,5-trioxane, oxetane, 18- Examples include ethers such as laur-6-ether and diphenyl ether, preferably carbonates, amides and ureas, more preferably 1,4-dioxane, 18-crown-6-ether and butyrolactone. , Ethylene carbonate, propylene carbonate, dimethylformamide, tetramethylurea, N-methylpyrrolidinone, 1,3-dimethylimidazolidinone, 1,3-dimethyl-2,4-imidazolidine-dione, particularly preferably ethylene carbonate, N-methylpyrrolidinone, 1,3-dimethylimidazolidinone, 1,3-dimethyl-2,4-imidazolidine-dione are used.

  The amount of the stabilizing solvent in the stabilizing solvent solution of lithium perfluorinated inorganic acid is preferably 0.5 to 10 mol, more preferably 1.0 to 7 mol per mol of lithium perfluorinated inorganic acid. 0 mol, particularly preferably 1.5 to 5.5 mol. By setting the abundance, the decomposition during the dehydration treatment of the lithium perfluorinated inorganic acid complex is suppressed.

  The stabilized solvent solution of lithium perfluorinated inorganic acid of the present invention has the general formula (1)

(In the formula, M represents a nonmetallic element or a metallic element, and n represents an integer of 1 to 6.)
It is obtained by mixing a water / organic solvent mixed solution of lithium perfluorinated inorganic acid represented by the above and a stabilizing solvent, followed by dehydration treatment.

  The water / organic solvent mixed solution of lithium perfluorinated inorganic acid, the water / organic solvent mixed solution of lithium perfluorinated inorganic acid is a lithium compound and a general formula (2)

(Wherein M and n are as defined above.)
It can obtain by making it react with the perfluorinated inorganic acid shown by the mixed solvent of water / organic solvent (for example, refer patent document 4).

  The dehydration treatment of the present invention is not particularly limited as long as it is an operation for removing water from the water / organic solvent mixed solution of lithium perfluorinated inorganic acid, but preferably an azeotropic solvent having an azeotropic composition with water is added. Later, water is removed while distilling off the organic solvent. The pressure is not particularly limited.

  The azeotropic solvent is not particularly limited as long as it has an azeotropic composition with water. For example, hydrocarbons such as benzene, toluene, xylene, mesitylene, naphthalene, and cyclohexane; chlorobenzene, bromobenzene, chloroform Halogenated hydrocarbons such as carbon tetrachloride and dichloroethane; Nitriles such as acetonitrile, propionitrile and acrylonitrile; Nitrated hydrocarbons such as nitromethane and nitrobenzene; Dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, etc. Carbonates such as propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, phenyl acetate, benzyl acetate, methyl butyrate, ethyl butyrate, propyl dairy, butyl butyrate and methyl benzoate Glass Nitrate esters such as propyl and butyl nitrate; ethers such as diethyl ether, dimethoxyethane, anisole, diphenyl ether, paraaldehyde and trioxane; ketones such as methyl ethyl ketone, butanone and pentanone; ethanol, propanol, butanol, pentanol and hexanol , Alcohols such as allyl alcohol, benzyl alcohol, furfuryl alcohol; phenols such as phenol and chlorophenol; pyridines such as pyridine and methylpyridine; formic acid, acetic acid, butyric acid, hydrochloric acid, hydrogen bromide, hydrogen iodide, nitric acid Examples of such acids include amines such as hydrazine and piperidine, preferably hydrocarbons, carbonates, carboxylic esters, nitriles, and more preferably carbonates. In addition, you may use the said azeotropic solvent in mixture of 2 or more types.

  The amount of the azeotropic solvent used is preferably 0.1 to 500 g, preferably 0.5 to 200 g, and more preferably 1 to 100 g with respect to 1 g of lithium perfluorinated inorganic acid.

  In the present invention, the perfluorinated inorganic acid lithium addition compound can be obtained by, for example, concentrating the stabilizing solvent solution of lithium perfluorinated inorganic acid and / or mixing with a poor solvent. Here, the lithium perfluorinated inorganic acid addition compound refers to a compound in which 1 to 6 molecules of stabilizing solvent are coordinated to lithium perfluorinated inorganic acid.

  The poor solvent is not particularly limited as long as it precipitates the perfluorinated inorganic acid lithium addition compound as a solid from the stabilized solvent solution of lithium perfluorinated inorganic acid, for example, pentane, hexane, heptane, octane, Aliphatic hydrocarbons such as decane and dodecane; Halogenated hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, dichloroethane, and tetrachloroethane; benzene, toluene, xylene, mesitylene, binary butylbenzene, trimethylbenzene, and triethylbenzene , Triisopropylbenzene, pentamethylbenzene, fluorobenzene, difluorobenzene, trifluorobenzene, perfluorobenzene, chlorobenzene, dichlorobenzene, trichlorobenzene, perchlorobenzene, bromoben Aromatic hydrocarbons such as benzene, dibromobenzene, tribromobenzene, iodobenzene, diiodobenzene, etc .: carbonates such as dibutyl carbonate, pentyl carbonate, hexyl carbonate, etc., preferably halogenated hydrocarbons; aromatic Group hydrocarbons, more preferably methylene chloride, chloroform, benzene, toluene, xylene are used.

  The amount of the poor solvent used is preferably 0.1 to 500 g, preferably 0.5 to 200 g, and more preferably 1 to 100 g with respect to 1 g of lithium perfluorinated inorganic acid.

  Next, the present invention will be specifically described with reference to examples, but the scope of the present invention is not limited thereto. The analysis of products and hydrolysates was performed by the following method.

Lithium hexafluorophosphate and its hydrolyzate;
Phosphorus nuclear magnetic resonance spectrum ( ³¹ P-NMR), internal standard; methyldiphenylphosphine oxide

Reference Example 1 (Synthesis of water / diethyl carbonate mixed solution of lithium hexafluorophosphate)
200 ml of diethyl carbonate and 51 g (953 mmol) of diethyl carbonate were added to a PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) container having a capacity of 500 ml equipped with a stirrer and a thermometer. While cooling to −10 ° C., 71.9 g (321 mmol) of 65% by mass hexafluorophosphoric acid aqueous solution (manufactured by Aldrich) was gently added dropwise while maintaining the liquid temperature at the same temperature. After completion of the dropwise addition, the mixture was reacted at 0 to 10 ° C. for 1 hour with stirring. After completion of the reaction, the reaction solution was filtered to obtain 354 g of a lithium hexafluorophosphate diethyl carbonate mixed solution (water / diethyl carbonate = 1/14). The mixed solution contained 48.8 g of lithium hexafluorophosphate (reaction yield: 100%).

Example 1 (Synthesis of an ethylene carbonate solution of lithium hexafluorophosphate)
38 g of a mixed solution of lithium hexafluorophosphate in diethyl carbonate synthesized in Reference Example 1 in a PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) container having a capacity of 500 ml equipped with a stirrer and a thermometer ( Lithium hexafluorophosphate (5.51 g = 34.4 mmol) and 413 mg (18.2 mmol) of lithium hydroxide were added and stirred for 15 hours. 17.3 g (196 mmol) of ethylene carbonate was added as a stabilizing solvent to the solution from which the solid had been removed by filtration, and the solvent was removed at 35 ° C. for 3 hours at a reduced pressure of 0.1 to 0.5 kPa. An ethylene carbonate solution of lithium phosphate (lithium hexafluorophosphate: ethylene carbonate = 1: 5.7 (molar ratio)) was obtained.

Example 2 (Synthesis of an ethylene carbonate addition compound of lithium hexafluorophosphate)
50 ml of anhydrous chloroform was added to the ethylene carbonate solution of lithium hexafluorophosphate obtained in Example 1 and the precipitated solid was filtered to obtain 15.8 g of an ethylene carbonate addition compound of lithium hexafluorophosphate as white crystals. Obtained (isolation yield; 87%). In addition, 3.82 molecules of ethylene carbonate were added to one molecule of lithium hexafluorophosphate. ^The number of additions of ethylene carbonate to lithium hexafluorophosphate calculated from ¹ H-NMR and ³¹ P-NMR was 3.9, and the area percentage by ³¹ P-NMR was 96%.
The physical properties of the ethylene carbonate complex of lithium hexafluorophosphate were as follows.

¹ H-NMR (CD ₃ CN, δ (ppm)): 4.46 (s, 4H)
³¹ P-NMR (CD ₃ CN, δ (ppm)): −144.9 (7-fold line)

Example 3 (Synthesis of 1,3-dimethyl-2-imidazolidinone addition compound of lithium hexafluorophosphate)
7.0 g of a lithium carbonate hexafluorophosphate solution synthesized in Reference Example 1 in a 100 ml PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) container having a stirrer and a thermometer (Lithium hexafluorophosphate 0.96 g = 6.4 mmol), 1.45 g (38 mmol) of 1,3-dimethyl-2-imidazolidinone was added as a stabilizing solvent, and the degree of vacuum was 0.1 to 0.5 kPa. The solvent was removed at 40 ° C. for 2 hours. When 30 ml of anhydrous toluene was added and the precipitated solid was separated by filtration, 3.6 g of 1,3-dimethyl-2-imidazolidinone complex of lithium hexafluorophosphate as white crystals was obtained (isolation yield 90%). ). The number of 1,3-dimethyl-2-imidazolidinone added to lithium hexafluorophosphate calculated from ¹ H-NMR and ³¹ P-NMR was 3.9, and the area by ³¹ P-NMR The percentage was 97%.
The physical properties of 1,3-dimethyl-2-imidazolidinone complex of lithium hexafluorophosphate were as follows.

¹ H-NMR (CD ₃ CN, δ (ppm)); 2.67 (s, 6H), 3.21 (s, 4H)
³¹ P-NMR (CD ₃ CN, δ (ppm)); -144.9 (seven-fold line)

Example 4 (Synthesis of 1,3-dimethyl-imidazolidinone-2,4-dione addition compound of lithium hexafluorophosphate)
The experiment was performed in the same manner as in Example 2 except that 4.99 g (38 mmol) of 1,3-dimethyl-imidazolidinone-2,4-dione was used as a stabilizing solvent, and lithium hexafluorophosphate as a white crystal was obtained. 2.55 g of 1,3-dimethyl-imidazolidinone-2,4-dione complex was obtained (isolation yield; 93%). The number of additions of 1,3-dimethyl-imidazolidinone-2,4-dione to lithium hexafluorophosphate calculated from ¹ H-NMR and ³¹ P-NMR is 2.0, and ³¹ P— The area percentage by NMR was 95%.

¹ H-NMR (CD3CN, δ (ppm)); 2.85 (s, 3H), 2.86 (s, 3H), 3.80 (s, 2H)
³¹ P-NMR (CD3CN, δ (ppm)); -144.9 (seven lines)

Example 5 (Synthesis of N-methylpyrrolidinone addition compound of lithium hexafluorophosphate)
An experiment was conducted in the same manner as in Example 2 except that 3.87 g (38 mmol) of N-methylpyrrolidinone was used as a stabilizing solvent, and 1.94 g of an N-methylpyrrolidine complex of lithium hexafluorophosphate was obtained as white crystals. (Isolated yield; 66%). The addition number of N-methylpyrrolidine to lithium hexafluorophosphate calculated from ¹ H-NMR and ³¹ P-NMR was 3.0, and the area percentage by ³¹ P-NMR was 96%.

¹ H-NMR (CD ₃ CN, δ (ppm)): 1.90 to 2.25 (m, 4H), 2.73 (s, 3H), 3.32 to 3.35 (m, 2H)
³¹ P-NMR (CD ₃ CN, δ (ppm)): −144.9 (7-fold line)

Example 6 (Synthesis of 1,3-dimethyl-imidazolidinone-2,4-dione-ethylene carbonate adduct of lithium hexafluorophosphate)
The experiment was conducted in the same manner as in Example 3 except that 2.17 g (19 mmol) of 1,3-dimethyl-imidazolidinone-2,4-dione and 1.67 g (19 mmol) of ethylene carbonate were used as the stabilizing solvent. As a crystal, 2.81 g of 1,3-dimethyl-imidazolidinone-2,4-dione / ethylene carbonate addition compound of lithium hexafluorophosphate was obtained (isolation yield: 95%). The numbers of addition of 1,3-dimethyl-imidazolidinone-2,4-dione and ethylene carbonate to lithium hexafluorophosphate calculated from ¹ H-NMR and ³¹ P-NMR were 1.98 and 0, respectively. .04, and the area percentage by ³¹ P-NMR was 91%.

¹ H-NMR (CD ₃ CN, δ (ppm)); 2.85 (s), 2.86 (s), 3.80 (s), 4.46 (s)
³¹ P-NMR (CD ₃ CN, δ (ppm)): −144.9 (7-fold line)

Example 7 (XRD measurement of various lithium hexafluorophosphate addition compounds)
Powder X-ray diffraction (XRD) measurement of various lithium hexafluorophosphate adducts obtained in Examples 2 to 5 was performed in a dry nitrogen atmosphere. As a result, all of the addition compounds showed a diffraction pattern clearly different from that of lithium hexafluorophosphate, and it was found that any of the compounds was not lithium hexafluorophosphate but an addition compound.

  INDUSTRIAL APPLICABILITY According to the present invention, a stabilized solvent solution of lithium perfluorinated inorganic acid useful as a catalyst for organic synthesis reaction, a dopant for semiconductor materials, and an electrolyte of a lithium ion battery can be provided.

Claims (2)

Lithium compounds and general formula (2)
(In the formula, M is phosphorus and n is 6.)
Obtained by reacting a perfluorinated inorganic acid represented by the formula (1) with a mixed solvent of water / organic solvent.
(In the formula, M is phosphorus and n is 6.)
And perfluorinated inorganic lithium water / organic solvent mixed solution shown in, such carbonate esters, amides, after mixing the stabilized solvent is ureas or a mixture thereof, to dehydration treatment, perfluorinated A method for producing a stabilized solvent solution of lithium inorganic acid.
However, the organic solvent and the stabilizing solvent are different. The amount of the stabilizing solvent in the stabilizing solvent solution of lithium perfluorinated inorganic acid is 0.5 to 10 moles per 1 mole of lithium perfluorinated inorganic acid. A method for producing a stabilized solvent solution of lithium acid.