SEARCH Articles Figures Tables 4- Amino phenol-2-sulfonic acid Acidic phenols Alkyl sulfonic acid esters of phenol Phenol acidity Phenol acids Phenol sulfonation Phenol-4-sulfonic acid, 2- copper complexes Phenolic acidity Phenolic acids Phenolics phenolic acids Phenols from sulfonic acids Phenols reaction with sulfonic acid Sulfonation, benzoic acid phenol Sulfonic acid amides phenols Sulfuric acid/sulfonated phenolics