2-Hydroxybenzenesulfonic acid

2-Hydroxybenzenesulfonic acid (CAS 609-46-1), commercially known as o-phenolsulfonic acid, is an aromatic sulfonic acid used across industrial processing as a pH buffer, catalyst, and surface-active agent. Its dual functional groups make it effective in applications requiring simultaneous acidification and surface modification within a single compound. In water treatment, it functions as a pH regulator and scale-control additive.

Textile and leather processors use it as a wetting and penetration agent to improve dye uptake and surface uniformity on fiber and hide substrates. It is essential for achieving consistent results in large-scale manufacturing. In coatings and adhesive formulations, it acts as a catalytic curing agent or adhesion promoter where controlled acidity is required. This versatility makes it a staple in chemical synthesis and material science.

Pharmaceutical manufacturers employ it as an intermediate in active ingredient synthesis and as a counterion source in salt formation processes. It ensures the stability and solubility of various medicinal compounds. 2-Hydroxybenzenesulfonic acid is supplied as an aqueous solution or as a crystalline solid, depending on concentration and handling requirements. Technical grade is the standard offering for industrial applications.

Purity specifications are typically confirmed by titration or HPLC to ensure consistency. Pharmaceutical-grade material is available from select producers where documentation supporting GMP compliance is required.