Acid brown 235

Preparation

4-Amino-5-hydroxynaphthalene-2,7-disulfonic acid?diazo, Coupled with resorcinol; 4-Nitrobenzenamine and 4-nitro-4′-aminoazobenzene-2-sulfonic acid?diazo, respectively, and the above product matches.

Properties and Applications

dark brown. Mainly used for leather shading.