Нафтол Желтый S

Химические свойства

light yellow powder

Использование

Naphthol Yellow S Hydrate is used in methods for dying of textiles.

Подготовка

4-Hydroxynaphthalene-1,3,6-trisulfonic acid or 1-Naphthol-4,7-disulfonic acid?or 1-Naphthol-2,7-disulfonic acid?or more of the latter with the nitro compounds and nitric acid reaction.

Определение

ChEBI: An organic sodium salt that is the disodium salt of 5,7-dinitro-8-hydroxynaphthalene-2-sulfonic acid.

Методы очистки

It is a water-soluble greenish yellow powder. The free sulfonic acid can be recrystallised from dilute HCl (m 150o) or AcOH/EtOAc (m 148-149.5o). The disodium salt is then obtained by dissolving the acid in two equivalents of aqueous NaOH and evaporating to dryness and drying the residue in a vacuum desiccator. The sodium salt can be recrystallised from the minimum volume of H2O or from EtOH [Dermer & Dermer J Am Chem Soc 61 3302 1939]. [Beilstein 11 III 542.]