Naphthionic acid is an organic compound with the formula C10H6(NH2)(SO3H). It is one of several aminonaphthalenesulfonic acids, which are derivatives of naphthalene containing both amine and sulfonic acid functional groups. Naphthionic acid is a white solid, although commercial samples can appear gray.[1] Deprotonation of naphthionic acid gives the sulfonate C10H6(NH2)(SO3)−, which is call naphthionate.
| Names | |
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| Preferred IUPAC name
4-Aminonaphthalene-1-sulfonic acid | |
| Other names
Piria's acid | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.001.425 |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| C10H9NO3S | |
| Molar mass | 223.24 |
| Appearance | white solid |
| Density | 1.6703 g/cm3 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Production and reactions
editNaphthionic acid is prepared by treating 1-aminonaphthalene with sulfuric acid.[2]
Naphthionic acid is used in the synthesis of azo dyes such as Rocceline (also known as Solid Red A). For this conversion sodium naphthionate is diazotated. The resulting diazonium derivative is coupled with β-naphthol.[2]
Heating a solution of sodium naphtionate induces its conversion to 1-aminonaphthalene-2-sulfonate.[2]
