Method for preparing 4-alkyl-2-hydroxy-3,5-dichlorobenzene sulphonic acids
US5684183A · kind A · utility
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4Claims
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Inventors
Key dates
| Filing date | Jul 1, 1996 |
| Grant date | Nov 4, 1997 |
| Priority date | — |
| Expiry date | Jul 1, 2016 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C303/22
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The invention is related to a method for preparing 4-alkyl-2-hydroxy-3,5-dichlorobenzene sulphonic acids by sulphonating 4-chloro-3-alkylphenol and by chlorinating 4-alkyl-2-hydroxy-5-chlorobenzene sulphonic acid present in an acidic reaction mixture. According to the invention, chlorination is carried out by adding, to the acidic reaction mixture, salts of hypochlorous and/or chloric acids and, when needed, hydrochloric acid or its salt.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.