1-hydroxynaphthalene-2-sulphonic acid Property

Melting point:

>249.85°C

Boiling point:

335.63°C (rough estimate)

Density 

1.4643 (rough estimate)

refractive index 

1.6000 (estimate)

pka

0.10±0.40(Predicted)

EPA Substance Registry System

2-Naphthalenesulfonic acid, 1-hydroxy- (567-18-0)

Hazard and Precautionary Statements (GHS)

1-hydroxynaphthalene-2-sulphonic acid Chemical Properties,Usage,Production

Chemical Properties

1-Hydroxynaphthalene-2-sulfonic acid [567-18-0]. Baum’s acid, C10H8O4S, Mr 224.23, is sparingly soluble in water and is precipitated from aqueous solution by hydrochloric acid. Coupling with diazo compounds and nitrosation both take place in the 4-position. Sulfonation gives 1-naphthol-2,4-disulfonic acid and nitration gives 2,4-dinitro-1-naphthol.

Preparation

The reaction of 1-naphthol with oleum in the cold yields a mixture of the 2- and 4- sulfonic acids; the former may be separated from the aqueous quenched reaction mixture by salting out the potassium salt after removing unreacted 1-naphthol.