Preparation
4-(2,4-Dinitrophenylamino)phenol?or?2-(2,4-Dinitroanilino)phenol?with similar?C.I. Sulphur Brown 5(C.I. 53245) the method, namely in the molten material of Copper sulfate monohydrate not under the condition of heating, vulcanizing temperature from 123 ℃ (in return) increase to 160 ℃ (roasting).