Process for the preparation of 4-fluorothiophenol
AssigneeBayer Aktiengesellschaft
InventorsHelmut Fiege, Ferdinand Hagedorn, Wolfgang Eymann, Otto Neuner, Herbert Muller
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Abstract
4-Fluorothiophenol is obtained in outstanding purifies and yields if 4-fluorobenzenesulphonyl chloride is reacted with sodium hydrogen sulphite solution to give a solution of sodium 4-fluorobenzenesulphinate, this solution is reduced with sulphur dioxide to give 4,4'-difluorodiphenyl disulphide and finally this is reacted with sodium borohydride in a water-miscible inert organic solvent to give 4-fluorothiophenol (sodium salt). Free 4-fluorothiophenol can be isolated from the sodium salt solution by acidification.
Claims10
A process for preparing the sodium salt of 4-fluorothiophenol or 4-fluorothiophenol itself, said process comprising the following steps:
- (A) reacting 4-fluorobenzene sulphonyl chloride with sodium hydrogen sulphite solution to yield a solution of sodium 4-fluorobenzensesulphinate;
- (B) reducing 4-fluorobenzenesulphinate with sulphur dioxide to yield 4,4'-difluorophenyl disulphide;
- (c) reacting 4,4'-difluorophenyl disulphide with sodium borohydride in a water-miscible inert organic solvent to yield the sodium salt solution of 4-fluorothiophenyl;
- and, optionally, if 4-fluorothiophenol itself is desired, then:
- (D) converting the sodium salt solution of 4-fluorothiophenol to 4-fluorothiophenol itself by acidification.
Dependencies are inferred from the claim text.