YELLOW TO YELLOW-BROWN CRYSTALLINE POWDER
Reduction of 2,4-Dinitrobenzenesulfonic Acid gives the colorant intermediate 1,3-diaminobenzene-4-sulfonic acid [88-63-1] as an alternative to the sulfonation of m-phenylenediamine.
2,4-Dinitrochlorobenzene is warmed with aqueous sodium sulfite to give an 80 % yield of the sodium salt of 2,4-Dinitrobenzenesulfonic Acid [885-62-1] as yellow needles after salting out. The lower reactivity of 2- and 4- chloronitrobenzene requires much higher temperature for this nucleophilic sulfitation, with too many side reactions to be practicable.
ChEBI: The arenesulfonic acid that is benzenesulfonic acid with two nitro substituents in the 2- and 4-positions.
