Method: 3-Amino-2-hydroxy-5-sulfobenzoic acid diazo, and 5-Aminonaphthalene-2-sulfonic acid acidcoupling, product diazo, again with 2-Hydroxybenzoic acid?coupling, and then will product (C.I.Mordant Brown 51, C.I. 26530) and water cut formic acid chromium heating (85 ~ 90 ℃), each 2-Hydroxybenzoic acid introduce a chrome atoms.
