Sodium Chloride → HCID 57234554, compound

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Reaction Steps

When the chlorination reaction is complete, the mixture is worked up according to known methods. After clarification by filtration, where required, the solution may be acidified with a mineral acid at room temperature or at a temperature of up to about 90°C, the bromination product which has precipitated may be separated, washed with water and dried at 100°-120°C. An especially pure product is obtained by salting out the resulting 4-bromo-naphthalic acid in the form of the disodium salt by an addition of sodium ions to the reaction solution, for example in the form of sodium chloride and/or sodium hydroxide, separating the salt and converting it into the anhydride by introducing it into a dilute mineral acid. The 4-bromo-naphthalic acid anhydride so obtained is a valuable intermediate product for the preparation of dyestuffs and optical brighteners of the series of the naphthalic acid derivatives substituted in 4-position by phenols, thiophenols and aromatic amines.

Provenance & Evidence