Claims
- 1. Process for the preparation of mono-alkali metal salts of 1-amino-8-naphthol-4,6-disulphonic acid, which comprises reacting a mixture of naphthylaminetrisulphonic acids and/or salts thereof containing over 40% by weight of 1-naphthylamine-4,6,8-trisulphonic acid relative to the amount of diazotizable substances with an alkali metal hydroxide solution under elevated pressure and at elevated temperature and isolating 1-amino-8-naphthol-3,6-disulphonic aacid (H-acid) and 1-amino-8-naphthol-4,6-disulphonic acid (K-acid), in each case in the form of their mono-alkali metal salts, from the hydrolysis mixture by adjusting its ph-value to a value in the range from 0 to 4 with a mineral acid and by diluting it by introducing 0.1 to 5 times the hydrolysis under pressure and separating off first the H-acid at a temperature in the range from 40.degree. to 100.degree. C. and then the K-acid at a temperature in the range from -5.degree. to 40.degree. C.
- 2. Process according to claim 1, wherein the isolation of the mono-alkali metal salt of 1-amino-8-naphthol-3,6-di-sulphonic acid (H-acid) is carried out at temperatures in the range from 50.degree. to 90.degree. C.
Priority Claims (1)
Number |
Date |
Country |
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2843680 |
Oct 1978 |
DEX |
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Parent Case Info
This is a continuation of Application Ser. No. 76,052, filed Sept. 17, 1979, now abandoned.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4111979 |
Kotera et al. |
Sep 1978 |
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4166826 |
Schossler et al. |
Sep 1979 |
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Continuations (1)
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Number |
Date |
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Parent |
76052 |
Sep 1979 |
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