Method for producing fluorine-containing sulfonylamide compound

Abstract

A method for efficiently removing impurities such as sodium ions, fluoride ions, chloride ions and fluorosulfate ions without reducing the yield of a target product, including a fluorine-containing sulfonylamide compound selected from the group consisting of fluorine-containing sulfonylamide, a metal salt thereof, an ammonium salt thereof and a quaternary ammonium salt thereof is washed with an aqueous solution of salt of sulfuric acid.

Claims

1. A method for producing a fluorine-containing sulfonylamide compound, the method comprising: mixing a fluorine-containing sulfonylamide compound represented by Formula [II]: ##STR00004## wherein R.sup.1 represents a fluorinated alkyl group having 1 to 6 carbon atoms or a fluorine atom; R.sup.2 represents a chlorine atom or a fluorine atom; M represents a lithium atom or an ammonium cation residue, and n is 1, with an aqueous solution of a salt of sulfuric acid selected from the group consisting of lithium sulfate and ammonium sulfate; and then removing the aqueous solution of a salt of sulfuric acid from the fluorine-containing sulfonylamide compound represented by Formula [II], wherein: when M is a lithium atom, the salt of sulfuric acid is lithium sulfate, and when M is an ammonium cation residue, the salt of sulfuric acid is ammonium sulfate.

2. The method for producing a fluorine-containing sulfonylamide compound according to claim 1, wherein the fluorine-containing sulfonylamide compound is a lithium or ammonium salt of bis(fluorosulfonyl)amide.

Description

EXAMPLES

(1) Hereinafter, the present invention will be explained more specifically below referring to the following Examples. The present invention is not intended to be limited to the following examples, and can, of course, be practiced with modification as appropriate within a range that can be adaptable to the purposes of the present invention, and those are all encompassed in the technical scope of the present invention.

Example 1

(2) The amount of sodium ions in bis(fluorosulfonyl)amide ammonium salt was previously determined by cation chromatography to be 35 ppm. 303.61 g of a butyl acetate solution containing 39.71 g of the bis(fluorosulfonyl)amide ammonium salt was washed with 66.25 g of a 20% by mass aqueous ammonium sulfate solution containing 0.5 molar equivalent of ammonium sulfate with respect to the bis(fluorosulfonyl)amide ammonium salt, and separated to give 305.80 g of a butyl acetate solution containing 37.89 g (yield 95.4%) of bis(fluorosulfonyl)amide ammonium salt. 10.58 g of the solution was sampled, and the solvent was removed in vacuo, and the amount of sodium ions was determined by cation chromatography to be 13 ppm.

(3) The amount of impurities, sodium ions, was significantly reduced by washing bis(fluorosulfonyl)amide ammonium salt with an aqueous ammonium sulfate solution while suppressing degradation of the target product.

Example 2

(4) 295.22 g of a butyl acetate solution containing 36.58 g of the bis(fluorosulfonyl)amide ammonium salt prepared in Example 1 was washed with 64.81 g of a 20% by mass aqueous ammonium sulfate solution containing 0.5 molar equivalent of ammonium sulfate with respect to the bis(fluorosulfonyl)amide ammonium salt, and separated to give 291.21 g of a butyl acetate solution containing 33.29 g (yield 91.0%) of bis(fluorosulfonyl)amide ammonium salt. 10.13 g of the solution was sampled, and the solvent was removed in vacuo, and the amount of sodium ions was determined by cation chromatography to be 4 ppm.

Comparative Example 1

(5) Experiment was performed in the same manner as in Example 1 except for using, instead of the aqueous ammonium sulfate solution, 26.73 g of a 20% by mass aqueous ammonium chloride solution containing 1.0 molar equivalent of ammonium chloride with respect to the bis(fluorosulfonyl)amide ammonium salt for 152.23 g of a butyl acetate solution containing 19.82 g of the bis(fluorosulfonyl)amide ammonium salt. As a result, 151.90 g of a butyl acetate solution containing 18.87 g (yield 95.2%) of bis(fluorosulfonyl)amide ammonium salt was obtained. The amount of sodium ions in the solution was determined by cation chromatography to be 22 ppm.

Comparative Example 2

(6) Experiment was performed in the same manner as in Example 2 except for using, instead of the aqueous ammonium sulfate solution, 24.89 g of a 20% by mass aqueous ammonium chloride solution containing 1.0 molar equivalent of ammonium chloride with respect to the bis(fluorosulfonyl)amide ammonium salt for 141.09 g of a butyl acetate solution containing 17.52 g of the bis(fluorosulfonyl)amide ammonium salt prepared in Comparative Example 1. As a result, 139.16 g of a butyl acetate solution containing 16.13 g (yield 92.1%) of bis(fluorosulfonyl)amide ammonium salt was obtained. The amount of sodium ions in the solution was determined by cation chromatography to be 15 ppm.

Example 3

(7) The amount of sodium ions in bis(fluorosulfonyl)amide lithium salt was previously determined by cation chromatography to be 23 ppm. 137.86 g of a butyl acetate solution containing 17.18 g of the bis(fluorosulfonyl)amide lithium salt was washed with 25.67 g of a 20% by mass aqueous lithium sulfate solution containing 0.5 molar equivalent of lithium sulfate with respect to the bis(fluorosulfonyl)amide lithium salt, and separated to give 146.11 g of a butyl acetate solution containing 16.92 g (yield 98.5%) of bis(fluorosulfonyl)amide lithium salt. 12.69 g of the solution was sampled, and the solvent was removed in vacuo, and the amount of sodium ions was determined by cation chromatography to be 15 ppm. The amount of impurities, sodium ions, was significantly reduced by washing bis(fluorosulfonyl)amide lithium salt with an aqueous lithium sulfate solution while suppressing degradation of the target product.

Example 4

(8) The amount of sodium ions in bis(fluorosulfonyl)amide ammonium salt was previously determined by cation chromatography to be 5 ppm, and the amount of fluoride ions, chloride ions and fluorosulfric ions (FSO.sub.3.sup.) was previously determined by anion chromatography to be 1179 ppm, 24 ppm, 1378 ppm, respectively.

(9) 56.37 g of butyl acetate was added to 95.64 g of a butyl acetate solution containing 19.81 g of the bis(fluorosulfonyl)amide ammonium salt (sample A). Then the mixture was washed with 33.08 g of a 20% by mass aqueous ammonium sulfate solution containing 0.5 molar equivalent of ammonium sulfate with respect to the bis(fluorosulfonyl)amide ammonium salt, and separated to give 152.24 g of a butyl acetate solution containing 17.84 g (yield 90.1%) of bis(fluorosulfonyl)amide ammonium salt. After that, 142.69 g of the butyl acetate solution containing 16.72 g of the bis(fluorosulfonyl)amide ammonium salt was washed with 31.00 g of a 20% by mass aqueous ammonium sulfate solution containing 0.5 molar equivalent of ammonium sulfate with respect to the bis(fluorosulfonyl)amide ammonium salt, and separated to give 140.14 g of a butyl acetate solution containing 14.92 g (yield 89.2%) of bis(fluorosulfonyl)amide ammonium salt (sample B).

(10) Part of the solution was sampled, and the solvent was removed in vacuo, and the amount of sodium ions (determined by cation chromatography), fluoride ions, chloride ions and fluorosulfate ions (FSO.sub.3.sup.) (determined by anion chromatography) was 1 ppm, 5 ppm, 3 ppm, 22 ppm, respectively.

(11) The amount of impurities such as fluoride ions, in addition to sodium ions, was significantly reduced by washing bis(fluorosulfonyl)amide ammonium salt with an aqueous ammonium sulfate solution.

Example 5

(12) A GL test piece experiment was performed using sample B which was obtained by washing of sample A and used in Example 4.

(13) A GL test piece was placed in a plastic container and 42.58 g of sample B was added to the container so that the liquid contact area of the GL test piece was 14 cm.sup.2. The test piece was left to stand at 25 C.

(14) Part of the solution was sampled 0 day and 1 day after being left to stand, and the solvent was removed in vacuo, and the amount of sodium ions was measured by cation chromatography. The result was <1 ppm, <1 ppm, respectively, in sample B. No increase was observed.

(15) The amount of impurities such as fluoride ions was significantly reduced by washing with an aqueous ammonium sulfate solution, and thus corrosion of GL and the resulting increase of sodium ions were suppressed.

Comparative Example 3

(16) A GL test piece experiment was performed in the same manner as in Example 5 except for using 46.14 g of a solution whose composition was the same as that of sample A instead of sample B.

(17) Part of the solution was sampled 0 day and 1 day after being left to stand, and the solvent was removed in vacuo, and the amount of sodium ions was measured by cation exchange chromatography. The result was 5 ppm, 30 ppm, respectively, in sample A. A significant increase was observed.