P-Aminobenzenesulfonic acid Sulfanilic

Problem 36.3 Account for the fact that p-aminobenzoic acid or < -aminobenzoic acid does not exist appreciably as the dipolar ion, but p-aminobenzenesulfonic acid sulfanilic acid) does. Hint What is Kb for most aromatic amines )... 

AI3-15414 Aniline-4-sulfonic acid Aniline-p-sulfonic acid Aniline-p-sulphonic acid Benzenesulfonic acid, 4-amino- CCRIS 4576 EINECS 204482-5 HSDB 5590 Kyselina sulfanilova NSC 7170 p-Aminobenzenesulfonic acid Sulfanilic acid Sulfanilsaure Sulphanilic acid. Used in dyestuffs, organic synthesis, medicine. 

PROBLEM 11.22 Methyl orange is an azo dye used as an indicator in acid-base titrations. (It is yellow-orange above pH 4.5 and red below pH 3.) Show how it can be synthesized from p-aminobenzenesulfonic acid (sulfanilic acid) and N,N-dimethylaniline. 

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