4-hydroxybenzenesulfonic acid

CAS: 98-67-9

Overview

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.

Physical Properties

Melting Point	52 °C
Boiling Point	275.14°C (rough estimate)
Density	1.337 g/cm³
Appearance	yellowish oily liquid
Color	White to Light yellow to Light red
Form	Liquid
Water Solubility	Soluble in water.
Vapor Pressure	69.8Pa at 20℃
Refractive Index	n 20/D 1.489
Log P	0.41 at 25℃

Safety & Handling

Danger GHS05 GHS07 Hazard Statements H290 May be corrosive to metals H302 Harmful if swallowed H314 Causes severe skin burns and eye damage H318 Causes serious eye damage H335 May cause respiratory irritation Precautionary Statements P234 Keep only in original packaging. P260 Do not breathe dust/fume/gas/mist/vapours/spray. P261 Avoid breathing dust/fume/gas/mist/vapours/spray. P264 Wash … thoroughly after handling. P270 Do not eat, drink or smoke when using this product. P271 Use only outdoors or in a well-ventilated area. P280 Wear protective gloves/protective clothing/eye protection/face protection. P316 Get emergency medical help immediately. P317 Get emergency medical help. P319 Get medical advice/attention if you feel unwell. P321 Specific treatment (see … on this label). P330 Rinse mouth. P363 Wash contaminated clothing before reuse. P390 Absorb spillage to prevent material damage. P405 Store locked up. P406 Store in a corrosion-resistant/… container with a resistant inner liner. P501 Dispose of contents/container in accordance with local regulations. P264+P265 Wash … thoroughly after handling. P301+P317 Get emergency medical help. P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing. P403+P233 Store in a well-ventilated place. Keep container tightly closed. P301+P330+P331 Rinse mouth. Do NOT induce vomiting. P302+P361+P354 IF ON SKIN: Take off immediately all contaminated clothing. Rinse skin with water/shower. P305+P354+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

Trade & Regulatory

HS Code	29089990
UN Number	2586
ADR Class	8
Packing Group	III
Storage Class	8A - Combustible corrosive hazardous materials

Other Names

Industries

Printing & Packaging Textile, Leather & Paper Personal Care & Cosmetics