2-Hydroxybenzenesulfonic acid

2-Hydroxybenzenesulfonic acid (CAS 609-46-1), commercially known as o-phenolsulfonic acid, is an aromatic sulfonic acid used as a pH buffer, catalyst, and surface-active agent.

Where is 2-Hydroxybenzenesulfonic acid used?

• Water treatment: pH regulator and scale-control additive
• Textile and leather: wetting and penetration agent improving dye uptake and surface uniformity
• Coatings and adhesives: catalytic curing agent or adhesion promoter where controlled acidity is required
• Pharmaceutical manufacturing: intermediate in active ingredient synthesis and counterion source in salt formation

Good to know: Pharmaceutical-grade material is available from select producers where documentation supporting GMP compliance is required.

Commercial specifications

• Purity specifications typically confirmed by titration or HPLC