Hydroxymethanesulfinic acid

Hydroxymethanesulfinic acid (CAS 79-25-4) is a reducing agent; the commercial form is its sodium salt.

Where is Hydroxymethanesulfinic acid used?

• Textile and leather: discharge agent for vat and reactive dyes, enabling precise color removal
• Paper: brightens mechanical pulp and controls residual color in recycled fiber streams
• Industrial and institutional cleaning: targets stubborn stains and oxidized soils where alkaline cleaners fall short
• Water treatment: neutralizes excess chlorine or hydrogen peroxide before discharge
• It breaks down colorants and oxidized compounds under controlled conditions.

Good to know: Purity and active content are typically confirmed by titration or redox assay.

Commercial specifications

• Sodium salt is the predominant commercial grade
• Packaging ranges from small bags to bulk quantities