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Refined ethylene sulfite

a technology of ethylene sulfite and ethylene sulfite, which is applied in the field of ethylene sulfite, can solve the problems of increasing the acid content of ethylene sulfite during preservation, the inability to use solvents and additives, and the impurities in ethylene sulfite produced by the above conventional methods. achieve the effect of improving the performance of the battery and high purity

Inactive Publication Date: 2005-08-04
MITSUBISHI CHEM CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

"The present invention provides a refined ethylene sulfite that can be used in batteries. The ethylene sulfite is produced by reacting ethylene glycol with thionyl chloride, and contains chloroethanol in an amount of not more than 1000 ppm. The refining process includes a rectification process and at least one purification process, such as washing with basic water, dehydration by refluxing, distillation (rectification B), or absorption. The electrolyte for a lithium battery contains ethylene sulfite with chloroethanol in an amount of not more than 1000 ppm. The lithium battery has an electrolyte with ethylene sulfite containing chloroethanol in an amount of not more than 1000 ppm."

Problems solved by technology

However, ethylene sulfite produced by the above conventional methods contains a large amount of impurities.
The ethylene sulfite produced by the conventional methods is unsuitable for a solvent and an additive for an electrolyte for a lithium secondary battery, since the ethylene sulfite contains impurities so much that the electrolyte does not have good storage stability.
For example, the electrolyte containing the ethylene sulfite produced by the conventional methods tends to cause an increase of acid content during preservation.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0050] The above parent raw ethylene sulfite was subjected to an absorbing treatment with an activated carbon (Sekado BW-50, produced by Shinagawa Chemicals Ltd.) as an absorbent, wherein the activated carbon was added in the raw ethylene sulfite in an amount of 10% and then the ethylene sulfite was agitated for 5 hours. The ethylene sulfite was further rectified in the same manner as the above Production (I).

[0051] The ethylene sulfite was rectified at a yield of 68%, and had a purity of 99.5%, and contained chloroethanol of 0.09%, ethylene glycol of 0.18% and total chlorine of 480 ppm.

example 2

[0052] The parent raw ethylene sulfite was added with a sodium hydrogen carbonate saturated solution in an amount of 30% by weight, was agitated for one hour and then left at rest for 30 minutes, and after that, the water phase was removed. After the resultant was added with water in an amount of 20% by weight, it was agitated for one hour. After it was left at rest for 30 minutes, the water phase was removed. The ethylene sulfite thus washed two times was dehydrated by dehydration process by total reflux distillation at an internal temperature of 70° C. and at a pressure of 20 Torr for 5 hours, while discharging water out of the system. The dehydrated ethylene sulfite was further rectified in the same manner as the Production (I).

[0053] The ethylene sulfite was rectified at a yield of 60.1%, and contained chloroethanol of 0.09%, ethylene glycol of 0.05% and total chlorine of 110 ppm.

example 3

[0054] The refined ethylene sulfite obtained in Example 2 was further treated by the absorbing treatment with a molecular sieve of 5 A as an absorbent, wherein the absorbent was added into the refined ethylene sulfite in an amount of 3%, and then the ethylene sulfite was agitated for 5 hours. After that, the treated ethylene sulfite was rectified in the same manner as the Production (I).

[0055] The ethylene sulfite was rectified at a yield of 54%, and contained chloroethanol of 0.01%, ethylene glycol of 0.01% or less and total chlorine of 40 ppm or less.

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Abstract

Refined ethylene sulfite exhibits excellent storage stability when used as a constituent of an electrolyte. Ethylene sulfite is formed by a step of reacting ethylene glycol and thionyl chloride to producing raw ethylene sulfite, a rectifying step for rectifying the raw ethylene sulfite, and a refining process for refining the raw ethylene sulfite or the rectified ethylene sulfite conducted before or after the rectifying step. The refining process is at least one process selected from the group consisting of a washing process, a dehydration process by total reflux distillation, a second rectifying process, and an absorbing process. Refined ethylene sulfite contains chloroethanol in an amount of not more than 1000 ppm.

Description

CROSS REFERENCE TO RELATED APPLICATION [0001] This is a continuation application of a patent application Ser. No. 10 / 227,242 filed on Aug. 26, 2002.BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT [0002] The present invention relates to ethylene sulfite, more particularly to refined ethylene sulfite which is useful for an application to an electrolyte. [0003] Ethylene sulfite is used as a raw material in various fields of organic synthesis, and a solvent or an additive for an electrolyte of a lithium secondary battery or the like. [0004] Examples of conventional methods for producing the ethylene sulfite are: [0005] i) a method of reacting ethylene glycol and thionyl chloride; [0006] ii) a method of reacting ethylene glycol and dimethyl sulfite; [0007] iii) a method of reacting ethylene oxide and sulfur dioxide; [0008] iv) a method of depolymerizing polyethylene sulfite. Among these methods, the method of reacting ethylene glycol and thionyl chloride has been considered advant...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C07D331/02H01M6/16H01M10/052H01M10/0567H01M10/0569H01M10/36
CPCC07D331/02H01M6/168Y02E60/122H01M10/0567H01M10/0569H01M10/052Y02E60/10
Inventor KATO, TOSHIMITSUMINE, NORIOKIKOTATO, MINORU
Owner MITSUBISHI CHEM CORP