Sodium dithionite

Sodium dithionite (CAS 7775-14-6), also sold as sodium hydrosulfite, is a powerful reducing agent used industrially for bleaching, stripping color, and preventing oxidation across multiple manufacturing sectors.

Its strong reducing capacity makes it a go-to reagent wherever controlled decolorization or oxygen scavenging is required at scale. In textile manufacturing, it is the primary reducing agent for vat dye application.

It reduces insoluble dyes to their soluble leuco form so they can penetrate fiber, then re-oxidize to fix color. Pulp and paper producers use it to brighten mechanical pulp without the fiber degradation associated with chlorine.

In food processing, it functions as an antioxidant and preservative, protecting products such as dried fruits, starches, and wine from discoloration and oxidative spoilage during storage and transport.

Water treatment operations apply it for dechlorination and oxygen removal in boiler feed systems and reverse osmosis pretreatment. It is supplied as a white to pale yellow powder or granules for industrial use.

Technical-grade material is the dominant commercial form, though food-grade specifications are available for applications in food and beverage processing where strict regulatory compliance is required.

Purity levels typically range from 85% to 90% for technical grade, with higher-purity grades available for sensitive applications. All batches are tested to ensure they meet necessary safety and performance metrics.