METHOD FOR MANUFACTURING SULFUR TETRAFLUORIDE

Abstract

An object of this invention is to provide a simple method for producing sulfur tetrafluoride. The object is achieved by a method for producing sulfur tetrafluoride, comprising step A of reacting a fluorinated halogen compound with sulfur chloride, the fluorinated halogen compound being represented by formula: XF.sub.n, wherein X is chlorine, bromine, or iodine; and n is a natural number of 1 to 5.

Claims

1-6. (canceled)

7. A composition comprising sulfur tetrafluoride and ICl, wherein the composition comprises 1.2 equivalents or less of the ICl with respect to the sulfur tetrafluoride in terms of molar ratio.

Description

EXAMPLES

[0093] Examples are given below to illustrate the present invention in more detail, but the present invention is not limited to these Examples.

[0094] The IF.sub.5-pyridine-HF complex used in the Examples is a known substance described in S. Hara, M. Monoi, R. Umemura, C. Fuse, Tetrahedron, 2012, 68, 10145-10150.

Example 1

Synthesis of SF.SUB.4 .(1)

[0095] A 300-mL flask was charged with 3.4 mL (11 g) of IF.sub.5, and 2.0 mL (3.4 g) of S.sub.2Cl.sub.2 was added dropwise with stirring at room temperature. A vigorous reaction occurred to generate gas. The gas was collected with a syringe and introduced into a gas cell, and its infrared spectrum was measured. The results showed absorption at 746.9 cm.sup.−1 and 820 cm.sup.−1, which are peaks of SF.sub.4. This indicated that SF.sub.4 was formed.

[0096] Generation of gas was not observed 1 hour after the completion of the dropwise addition. It was thus presumed that the reaction had already been completed.

[0097] No solid products were visually observed.

Example 2

Synthesis of SF.SUB.4 .(2)

[0098] An autoclave was charged with 3.47 g (25.7 mmol) of S.sub.2Cl.sub.2 at room temperature. After cooling, the pressure in the reactor was reduced, and 10.5 g (47.2 mmol) of IF .sub.5 was placed in the reactor.

[0099] After the mixture was stirred for 3.5 hours, cooling was stopped, and the temperature thereof was slowly brought back to room temperature. As a result, the pressure was increased to 0.6 MPa.

[0100] A cylinder was connected to the autoclave. The generated gas was liquefied and recovered in the cylinder by cooling the cylinder, thereby obtaining 4.57 g of SF.sub.4 (yield: 82%).

[0101] In the autoclave, 9.4 g of liquid remained. This liquid was collected, and .sup.19F-NMR measurement showed peaks of IF.sub.5.

[0102] No solid products were visually observed. When titration of a part (0.3959 g) of the liquid with 0.1 N sodium thiosulfate was performed until the color disappeared, 34 mL of 0.1 N sodium thiosulfate was required. This neutralized solution was diluted 400-fold with pure water, and the weight ratio of iodine, chlorine, and fluorine in the diluted solution was determined by using ion chromatography and a fluoride ion electrode. The weight ratio was the following: iodine: 73%; chlorine: 22.3%; and fluorine: 1.7%. This result showed that in addition to SF.sub.4, ICl was produced as a main by-product.

Example 3

Recovery of Iodine

[0103] 10 mL of 30% hydrogen peroxide solution was added to 30 mL of the aqueous solution containing iodine ions obtained in Example 2 to precipitate iodine. By filtration, 0.24 g of the precipitated iodine was recovered.

[0104] The recovery was 95%.

Example 4

Synthesis of SF.SUB.4 .(3)

[0105] An autoclave (volume: 200 mL) was charged with 3.85 g (12 mmol) of an IF.sub.5-pyridine-HF complex. After addition of 2.5 mL of dichloromethane and cooling, 0.48 mL (6 mmol) of S.sub.2Cl.sub.2 was added dropwise. No generation of heat or gas was observed.

[0106] The autoclave was sealed and then gradually heated to 70° C. in an oil bath. After 20 minutes, the pressure was increased to 0.3 MPa, which indicates formation of gas.

[0107] After stirring for 3 hours, the temperature thereof was cooled to room temperature, and a cylinder was connected to the autoclave.

[0108] The generated gas was liquefied and recovered in the cylinder by cooling the cylinder, thereby obtaining 0.9 g of SF.sub.4 (yield: 69%).