Sulfanilic acid

Sulfanilic acid (CAS 121-57-3), also known as sulphanilic acid, is an aminosulfonic acid; a key intermediate in the synthesis of azo dyes, optical brighteners and specialty chemicals.

Where is Sulfanilic acid used?

• Textile dyeing: diazotized and coupled with naphthol or other aromatic compounds to produce direct and reactive azo dyes on cotton and wool
• Paper and packaging: manufacture of fluorescent whitening agents that improve brightness in coated and uncoated paper grades
• Leather processing: derivatives achieve penetrating coloration on finished hides
• Polymeric colorants: cross-linking component
• Printing inks: production of pigment dispersants
• Its amine and sulfonic acid groups make it a building block for coupling reactions in dye manufacturing and industrial chemical synthesis.

Good to know: Technical grade is the standard commercial form, with purity typically specified at 99% minimum for dye intermediate applications; reagent-grade material is available for laboratory use.

Commercial specifications

• Purity typically 99% minimum (technical grade)