monosulfonated

Monosulfonated refers to a molecule that bears exactly one sulfonic acid group (–SO3H) or sulfonate group (–SO3−) in its structure. The term distinguishes such compounds from disulfonated, trisulfonated, or poly-sulfonated derivatives. Monosulfonation can occur on aromatic rings or on aliphatic substrates, and the sulfonic group may be present in the protonated form or as a salt, depending on the pH.

In synthesis, monosulfonated products are often obtained by controlled sulfonation using sulfuric acid or oleum, with directing groups and temperature control to avoid multiple substitutions. Some substrates require alternative routes or protective group strategies to achieve a single sulfonic group. Properties typically include strong acidity, since aryl sulfonic acids have very low pKa values, and high water solubility in their salts. Monosulfonated compounds often serve as intermediates or building blocks in organic synthesis, as well as components in catalysis and separation processes.

Common examples of monosulfonated compounds include benzenesulfonic acid and p-toluenesulfonic acid (p-TsOH). These compounds are widely used as reagents and catalysts and serve as reference points for monosulfonated chemistry. Monosulfonated derivatives are important in dye chemistry, pharmaceuticals, polymer science, and materials research, where the sulfonic group provides ionic character and water solubility, influencing reactivity, solubility, and interaction with other materials.