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.

Naphthionic acid
Names
Preferred IUPAC name
4-Aminonaphthalene-1-sulfonic acid
Other names
Piria's acid
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.001.425 Edit this at Wikidata
EC Number
  • 201-567-9
UNII
  • InChI=1S/C10H9NO3S/c11-9-5-6-10(15(12,13)14)8-4-2-1-3-7(8)9/h1-6H,11H2,(H,12,13,14)
    Key: NRZRRZAVMCAKEP-UHFFFAOYSA-N
  • InChI=1/C10H9NO3S/c11-9-5-6-10(15(12,13)14)8-4-2-1-3-7(8)9/h1-6H,11H2,(H,12,13,14)
    Key: NRZRRZAVMCAKEP-UHFFFAOYAN
  • c1ccc2c(c1)c(ccc2S(=O)(=O)O)N
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).

Production and reactions

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Naphthionic 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]

References

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  1. 4-Amino-1-naphthalenesulfonic acid; MSDS No. 250619; Sigma–Aldrich Chemie GmbH: Steinheim, 29 Dec 2011.
  2. 1 2 3 Gerald Booth "Naphthalene Derivatives" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a17_009.