Нафталин-2,7-дисульфоновая кислота

Химические свойства

White, crystalline solid.Soluble in water. Combustible. Naphthalene-2,7-disulfonic acid [92- 41-1]. C10H8O6S2, Mr 288.28; the sodium salt of Naphthalene-2,7-disulfonic acid is much more soluble than that of the 2,6- isomer but can be isolated and purified by precipitation of the calcium salt at lower temperature followed by recrystallization.

Использование

Intermediate for dyes. The disodium salt of 8 gives 2-hydroxynaphthalene-7-sulfonic acid or 2,7-dihydroxynaphthalene by fusion processes. Sulfonation by oleum gives the 1,3,6-trisulfonic acid, and nitration gives 1-nitronaphthalene-3,6- disulfonic acid. In sulfuric acid solution, the disodium salt of naphthalene-2,7-disulfonic acid undergoes an unusual reaction at the 4-position with 4,40 -bis- (dimethylamino)benzhydrol. The resulting condensation product is oxidized with lead dioxide to give the acid basic dye C.I. Acid Green 16.

Определение

ChEBI: A naphthalenesulfonic acid in which the sulfo groups are attached to positions 2 and 7 of the naphthalene ring.

Методы очистки

Crystallise the acid from conc HCl. The disulfonamide has m 273o (from EtOH). [Beilstein 11 II 119, 11 III 463.]