Naphthol AS

Description

Naphtol AS is a coupling agent in cotton dying. Occupational dermatitis was reported in a woman involved in needlework, probably sensitized from occupational contact with clothes.

Chemical Properties

beige powder

Uses

Naphtol AS was used as off-the-shelf color-based anion sensors in organic solvents.

Preparation

aniline and 3-Hydroxy-2-naphthoic acid?condensation.

Hazard

Low toxicity by ingestion.

Contact allergens

Naphthol AS is a coupling agent in cotton dyeing, inducing occupational dermatitis or contact allergy in consumers in contact with cotton-dyed clothing. It has been indirectly reported as a cause of occupational allergy due to its coupling with Diazo Component 51, or as a crosssensitizer or sensitizer associated with Pigment Red 23 in red parts of tattoos. Pigmented contact dermatitis is usual in patients with a high phototype.

Purification Methods

Crystallise it from xylene or AcOH which forms plates m 243-244o [Schnopper et al. Anal Chem 31 1542 1959]. [Beilstein 12 H 505.]

Properties and Applications

rice or small red powder, melting point of 243 ~ 244 ℃, more sensitive to the air. In sodium hydroxide solution for yellow in liquid, insoluble in water and sodium carbonate solution, slightly soluble in ethanol, soluble in hot the difficulties. This product is widely used in the cotton fabric dyeing and printing. Dyeing cotton, cotton affinity is low, medium coupled ability. Can also be used for cotton yarn, polyester/cotton, PVA, viscose, silk and vinegar fiber dyeing, also can undertake direct printing, and reactive dye printing and cotton fabrics with the dye printing, discharge printing, the reactive dyes color printing and dyeing, and used to make quick pigment, fast amine element, element and organic pigment fast sulfonylurea medications.