Claims
- 1. A process for the preparation of 1-aminonaphthalene-2,4,7-trisulphonic acid which comprises the steps
- (a) reacting 1-nitronaphthalene by the Piria method with bisulphites,
- (b) sulphonating the sulphamate mixture obtained in this Piria reaction with sulphur trioxide in sulphuric acid and
- (c) isolating the 1-amino-naphthalene-2,4,7-trisulphonic acid from the sulphonation mixture.
- 2. The process of claim 1, wherein the sulphur trioxide is employed in the form of oleum.
- 3. The process of claim 2, wherein the sulphur trioxide is employed in the form of 20 to 100% strength by weight oleum.
- 4. The process according to claim 1, wherein the amount of sulphur trioxide is chosen so that 1.5 to 10 mol of sulphur trioxide are present per mol of 1-nitronaphthalene employed in the Piria reaction.
- 5. The process according to claim 1, wherein the sulphamate mixtures employed are those mixtures which are obtained on concentration of those aqueous reaction solutions obtained when 1 mol of 1-nitronaphthalene, suspended in water, is heated with an aqueous solution of 3 to 5 mol of ammonium or alkali metal bisulphite and 1.5 to 3 mol of ammonia or aqueous alkali metal hydroxide solution to 100.degree. to 105.degree. C.
- 6. A process for the preparation of 1-aminonaphthalene-7-sulphonic acid (1,7-Cleve's acid) from 1-nitronaphthalene, which process comprises
- (a) reacting 1-nitronaphthalene by the Piria method with bisulphites,
- (b) sulphonating the sulphamate mixture obtained in this Piria reaction with sulphur trioxide in sulphuric acid and
- (c) hydrolysing the sulphonation mixture obtained in step (b).
- 7. The process of claim 6, wherein the hydrolysis is carried out in 60 to 80% strength sulphuric acid.
Priority Claims (1)
Number |
Date |
Country |
Kind |
3531923 |
Sep 1985 |
DEX |
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Parent Case Info
This is a continuation of application Ser. No. 900,215, filed Aug. 26, 1986 now abandoned.
Foreign Referenced Citations (2)
Number |
Date |
Country |
22545 |
Sep 1882 |
DEX |
15223 |
Jun 1894 |
GBX |
Non-Patent Literature Citations (1)
Entry |
Donaldson, "The Chemistry and Technology of Naphthalene Compounds", Edward Arnold (Publishers) Ltd., 1958, pp. 184-191, 198-199 and 208-209. |
Continuations (1)
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Number |
Date |
Country |
Parent |
900215 |
Aug 1986 |
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