反应详情

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.

1. customWhen the chlorination reaction
2. filtrationAfter clarification by filtration, where
3. custommay be acidified with a mineral acid at room temperature or at a temperature
4. customup to about 90°C
5. customthe bromination product which has precipitated may
6. custombe separated
7. washwashed with water
8. customdried at 100°-120°C
9. customAn especially pure product is obtained
10. additionby introducing it into a dilute mineral acid