- Process for preparing 2,4-dichloro-3-alkyl-6-nitrophenols
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2-4-Dichloro-3-alkyl-6-nitrophenols which are useful as intermediate of cyan couplers in color photography are prepared by sulfonating 4-chloro-3-alkyl-phenols to obtain 5-chloro-4-alkylhydroxybenzenesulfonic acids, chlorinating the acids in an aqueous phase to obtain 3,5-dichloro-4-alkyl-2-hydroxybenzenesulfonic acids and nitrating the sulfonic acids.
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- Process for producing 2,4-dichloro-3-alkyl-6-nitrophenol
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2,4-Dichloro-3-alkyl-6-nitrophenol, which is a precursor of 2,4-dichloro-3-alkyl-6-aminophenol useful for the production of a cyan coupler to be used with a sensitive material in the field of a photography in color, is industrially advantageously produced by (a) nitration of 2,4,5-trichloro-3-alkylbenzene, followed by hydrolysis of the resulting 2,4,5-trichloro-3-alkyl-6-nitrobenzene, or (b) hydrolysis of 2,4,5-trichloro-3-alkylbenzene-6-sulfonic acid or a salt thereof, followed by nitration of the resulting 2,4-dichloro-3-alkylphenol-6-sulfonic acid or a salt thereof, the starting material usable for these processes being 4-alkylbenzenesulfonic acid or a salt thereof, which is easily available.
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- Preparation of 2,4-dichloro-3-alkyl-6-nitrophenols
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2,4-Dichloro-3-alkyl-6-nitrophenols are prepared by chlorinating, with chlorine in the presence of a catalyst, 1-alkyl-4-nitrobenzenes having a C2 -C8 -alkyl radical until the content of trichloroalkylnitrobenzenes is at least 60% by weight in the chlorination mixture, removing the catalyst from the chlorination mixture, then hydrolyzing the chlorination mixture, removing the precipitated reaction product, and treating it with an aqueous inorganic acid. The 2,4-dichloro-3-alkyl-6-nitrophenols are new.
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