NAPHTHOL YELLOW S

Chemical Properties

light yellow powder

Uses

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

Uses

Dye for wool, silk.

Definition

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

Preparation

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.

Purification Methods

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.]

Properties and Applications

colourful green light yellow. Soluble in cold water and hot water yellow, in 0 ℃ when solubility of 8%, slightly soluble in alcohol. Meet strong sulfuric acid is green light yellow, diluted colored light become weak. Its water solution to join sodium hydroxide have floc; Join chloride-ferric chloride solution from yellow to become yellow light brown. Apply to wool, polyamide fiber dyeing, coloured paper colourful yellow, the heavy metal salt can be used for printing ink and rubber color. Can also be used for soap, drug, cosmetics, biological and leather dyeing.

Standard	Light Fastness	Soaping		Persperation Fastness	Oxygen bleaching		Fastness to seawater
		Fading	Stain		Fading	Stain	Fading	Stain
ISO	1	1	5	3	1	5	1	1
AATCC	1	2	2	1	1	1	2	2