4-hydroxybenzenesulfonic acid

4-Hydroxybenzenesulfonic acid (CAS 98-67-9), also known as phenolsulfonic acid or sulfocarbolic acid, is an aromatic sulfonic acid used across industrial processing and formulation chemistry. It functions primarily as a pH buffer, UV stabilizer, and preservation agent in manufacturing workflows where precise acidity control and oxidative stability are required for the final product.

In textile dyeing and leather tanning, it acts as a fixative and pH regulator, improving dye uptake and process consistency across batch production cycles and large scale industrial operations. Printing ink and packaging coating formulators incorporate it to stabilize pigment dispersions and extend shelf life against UV-induced degradation in various environmental conditions.

In personal care formulations, it supports preservation systems and contributes to UV stabilization in products where phenolic-based protection is commercially preferred by manufacturers. Paper treatment processes use it as a buffering agent to control acidity during pulp processing and surface sizing, ensuring the structural integrity and quality of the finished paper goods.

This chemical is supplied as an aqueous solution, with 65–70% concentration being the most commonly traded commercial form for global distribution and bulk industrial procurement. Technical grade is the standard offering for industrial applications in textiles, printing, and leather processing. Purity specifications may vary depending on specific application requirements.