6388. 2-Naphthol-6,8-disulfonic Acid

Nomenclature

CAS number: 118-32-1
7-Hydroxy-1,3-naphthalenedisulfonic acid; 2-hydroxynaphthalene-6,8-disulfonic acid; G acid.
C10H8O7S2; mol wt 304.30.
C 39.47%, H 2.65%, O 36.80%, S 21.07%.

Description and references

Prepd by heating β-naphthol with concd H2SO4, 2-naphthol-3,6-disulfonic acid (R acid) being obtained as a byproduct: Fierz-David, Blangey, Fundamental Processes of Dye Chemistry (Interscience, New York, 1949) p 197; see also Forster, Keyworth, J. Soc. Chem. Ind. London 46, 27T (1927).

Chemical structure

Derivative

Sodium salt.

Nomenclature

G salt.

Properties

Platelets or prisms. Freely sol in water, sol in dil alcohol.

Derivative

Barium salt octahydrate.
C10H6BaO7S2.8H2O; mol wt 583.73.
C 20.58%, H 3.80%, Ba 23.53%, O 41.11%, S 10.99%.

Properties

Minute prisms. Freely sol in water. Practically insol in alcohol, even when much dil with water.

Use

In the manuf of azo dyes, see Crossley, Resenvelt, Ind. Eng. Chem. 16, 271 (1924).