4-aminonaphthalene-1,7-disulfonic acid Property

Boiling point:

205.8°C (rough estimate)

Density 

1.6329 (rough estimate)

refractive index 

1.7330 (estimate)

pka

-0.84±0.40(Predicted)

EPA Substance Registry System

1,7-Naphthalenedisulfonic acid, 4-amino- (85-74-5)

Safety

RIDADR 

1759

HazardClass 

8

PackingGroup 

III

Hazard and Precautionary Statements (GHS)

4-aminonaphthalene-1,7-disulfonic acid Chemical Properties,Usage,Production

Description

1-Aminonaphthalene-4,6-disulfonic acid [85-74-5]. (4-aminonaphthalene-1,7-disulfonic acid), Dahl’s acid II, C10H9NO6S2, Mr 303.3, and its alkali-metal salts are soluble in water; the calcium salt is soluble in aqueous ethanol. Caustic fusion at 180℃ yields 1-amino-6-hydroxynaphthalene-4-sulfonic acid, but at higher temperature 4,7-dihydroxynaphthalene1-sulfonic acid is formed. Sulfonation with 35 % oleum at 80℃ gives 1-aminonaphthalene-2,4,6-trisulfonic acid.

Preparation

Naphthionic acid is sulfonated with 25 % oleum at 20℃ to give a 70 : 30 mixture of 1,4,7- and 1,4,6-trisulfonic acids, which is used as mixed Dahl’s acids.