2-Naphthalenesulfonic acid, 5,5'-[methylenebis[(3-methyl-4,1-phenylene)azo]]bis[6-hydroxy-, disodium salt

Preparation

4-(4-Amino-2-methylbenzyl)-3-methylbenzenamine?nitriding, and methane 6-Hydroxynaphthalene-2-sulfonic acid (2 Moore) coupled.

Properties and Applications

red light orange. Soluble in water for palm orange, soluble in ethanol for gold orange. The strong sulfuric acid for blood-red, diluted orange for palm. In aqueous solution is to add strong hydrochloric acid have the red orange precipitation; Add thick sodium hydroxide solution for orange brown. Used for wool, silk fiber dyeing, etc. Also used in paper shading.

Standard	Light Fastness	Soaping		Persperation Fastness	Oxygen bleaching		Fastness to seawater
		Fading	Stain		Fading	Stain	Fading	Stain
ISO	3	4	3	2-3	3		3-4