BASIC BROWN 4 - Product Name - BISMARCK BROWN R - C.I. NO. 21010 - CAS NO. 5421-66-9 - Molecular Formula C21H24N8 - Formula Weight 461.40 - Appearance Brownish Black Powder -C.I. BASIC BROWN 4 - 8005-78-5 - Bismarck Brown TSS - Bismarck Brown RLNS - EINECS 232-341-8 -Nitrous acid, reaction products with 4-methyl-1,3-benzenediamine hydrochloride - FT-0622582 Application area: Used for the dyeing of chemical fiber and direct printing of fabrics, Used for the dyeing of silk, wool, and cotton fibers, with less fastness compared with basic green & Also used for dyeing of leather, paper, feather, grass, wood, and bamboo.