PURIFICATION OF BETA-CHLOROETHANESULFONIC ACID SODIUM SALT

Japanese Patent JP3291841

B2

PURPOSE: To remove impurities such as inorganic salts and 1,2-ethanedisulfonic acid sodium salt (EDS) from the subject compound to an extreme degree and to obtain the crystal of the purified compound by crystallization and filtration taking advantage of the dissolution equilibrium relationship using water as the medium.
CONSTITUTION: An aqueous solution of β-chloroethanesulfonic acid sodium salt (CES) containing impurity inorganic salts and obtained by the reaction of 1,2-dichloroethane with sodium sulfite or reaction of vinyl chloride with sodium bisulfate is heated under reduced pressure (preferably under absolute pressure of 150-170mmHg) while keeping the boiling point to ≤90°C (preferably ≤75°C) to evaporate water from the solution. The solution is filtered under heating at a temperature higher than the above temperature and sodium chloride containing Glauber's salt is separated from the system as a filter cake to obtain a filtrate having decreased inorganic salt concentration. The filtrate is cooled to 15-35°C to effect preferential crystallization of CES. After removing CES, the filtrate is incorporated with ≥45wt.% of an inorganic salt and heated at 50-70°C to increase the dissolved inorganic salt concentration. The obtained solution is cooled to precipitate a part of EDS, the precipitate is removed by filtration and the filtrate is recycled and reused.

Toru Matsuoka
Yutaka Kaneuchi

JP14911893A

June 17, 2002

June 21, 1993

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Tosoh Corporation

C07C303/32; C07C303/44; C07C309/06; (IPC1-7): C07C309/06; C07C303/32; C07C303/44

JP249761A
JP6122061A

【文献】米国特許2600287(US,A)

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