2243-76-7

brown powder

4-Nitrobenzenamine diazotization, and 2-Hydroxybenzoic acid?coupling.

dark yellow orange and brown. Dye soluble in water and Etanol be golden yellow, slightly soluble in Acetone and Cellosolve, insoluble in other organic solvent. In concentrated sulfuric acid to red light yellow, shallow green light yellow after diluted produce precipitation; In concentrated nitric acid for yellow to amber solution. Dye aqueous solution to join concentrated hydrochloric acid have green yellow precipitation; Add Sodium hydroxide solution for red wheat brown. Mainly used for wool, silk, nylon dyeing, also can be in wool and silk printing. Can also be used in electrochemical silver, biological coloring and indicator, wall paper and leather tinting.

Standard	Ironing Fastness	Light Fastness	Fulling		Persperation Fastness	Soaping	Water
			Alkali	Acid
ISO	2	4	4	1-2	5	4-5	4-5
AATCC	Dry 2,wet 5	4	4		4	4	3-4

The free acid is precipitated by adding HCl to an aqueous solution of the Na salt. After 2 recrystallisations from aqueous AcOH, it has m 255o(dec); [m 253-254o(dec) was reported by Hewitt & Fox J Chem Soc 79 49 1901]. The free acid recrystallises from dilute AcOH as orange brown needles. The Na salt changes colour from yellow to red when the pH is increased from 10.2 to 12.0. [Woodland et al. J Am Chem Soc 75 5835 1953, Beilstein 16 IV 372.]