Sodium Perborate Monohydrate – Active Oxygen Bleach
Sodium Perborate Monohydrate (CAS 10332-33-9): Properties and Applications
1. Introduction
Sodium perborate monohydrate is an important inorganic peroxygen compound that serves as a stable source of active oxygen. It is widely used in laundry detergents, cleaning products, disinfectants, and tooth whitening formulations. Its oxidizing properties make it effective for stain removal, bleaching, and disinfection, but its chemical activity also requires careful attention to safety and proper storage conditions.
2. Chemical Composition and Structure
Molecular formula: NaBO₃·H₂O (or BNaO₃·H₂O)
Molecular weight: 99.81 g/mol
CAS number: 10332-33-9
EC number: 231-556-4 (also listed as 600-419-4)
Appearance: White, odorless, crystalline powder or granules
Active oxygen content: Approximately 16% (theoretical maximum), about 50% higher than the tetrahydrate form on an equal-weight basis
Solubility: Limited solubility in water; releases active oxygen upon dissolution
3. Mechanism of Action
Upon dissolution in water, sodium perborate monohydrate hydrolyzes to release hydrogen peroxide and sodium metaborate. This process can be accelerated by temperature or the presence of bleach activators such as TAED (tetraacetylethylenediamine). The released active oxygen provides effective bleaching, stain removal, and disinfection. Sodium perborate is classified as a strong oxidizing agent, with its oxidizing power forming the basis for its primary applications in bleaching, disinfection, and chemical synthesis.
4. Applications
Laundry detergents and household cleaning: A key ingredient in powder detergents and bleach products, where active oxygen removes stains and disinfects. The monohydrate form has less tendency to cake during storage under high humidity compared to the tetrahydrate.
Tooth whitening and oral care: Used in tooth bleaching formulations. Also has antiseptic and disinfectant properties, making it suitable for use as an oral debriding agent or oral wound cleanser.
Disinfection and antiseptics: Used in pharmaceutical and antiseptic products due to its stable oxidative properties.
Chemical synthesis: Serves as a convenient, stable, and relatively non-toxic oxidizing agent for various oxidation reactions, including the synthesis of amides from nitriles.
5. Safety and Toxicology
Hazards: Sodium perborate monohydrate is classified as an oxidizer that may intensify fire (H272). It is harmful if swallowed (H302) and causes serious eye damage. It may also damage fertility and the unborn child (H360Df). Inhalation of dust may cause respiratory irritation.
Toxicity data: Acute oral LD₅₀ in rats ranges from 770 to 2100 mg/kg.
First aid and handling: In case of inhalation, remove to fresh air. Use only under a chemical fume hood; do not breathe dust; do not get in eyes, on skin, or on clothing. If swallowed, seek immediate medical assistance.
Storage: Store in a cool, dry place, in tightly sealed containers. Keep away from combustible materials and sources of ignition.
6. Conclusion
Sodium perborate monohydrate (CAS 10332-33-9) is a powerful and widely used oxidizing agent in bleaching, cleaning, and disinfecting products. Its ability to release active oxygen upon dissolution makes it effective for stain removal, whitening, and antimicrobial action. At the same time, the compound presents potential health and safety risks, including oxidative hazards, eye damage, and reproductive toxicity, which necessitate strict handling and storage precautions. When used in accordance with safety regulations and proper industrial practices, sodium perborate monohydrate remains a key component in modern detergent, cleaning, and specialty product formulations.