5-Nitro-o-toluenesulfonic Acid is a precursor to 4,4''-dinitrostilbene-2,2''-disulfonic acid in fluorescent whitener.
??
ChEBI: The arenesulfonic acid that is toluene-2-sulfonic acid bearing a nitro substituent at C-4.
?? ??
4-Nitrotoluene is sulfonated with 25 % oleum at 60 ℃ and worked up to give a solution of the sodium salt of 2-Methyl-5-nitrobenzenesulfonic acid.
?? ??
4-Nitrotoluene-2-sulfonic acid is an essential intermediate for producing fluorescent whitening agents, thousands of tons of which are manufactured annually. It is used principally as starting material for the production of 4,4'-dinitrostilbene-2,2'-disulfonic acid, which in turn is used for the manufacture of a host of fluorescent whitening agents based on cyanuric chloride of the 4,4'-bis([1,3,5-triazin-2-yl]amino)-stilbene-2,2'-disulfonic acid type. Further substantial amounts of 4-nitrotoluene-2-sulfonic acid are required to synthesize fluorescent whitening agents with other basic structures and of various dyes.
