Sodium Metabisulfite
Sodium Metabisulfite introduction
Other names: sodium pyrosulfite
CAS No.: 7681-57-4
Molecular Formula: Na2S2O5
Molecular Weight: 190.10
White or light yellow crystalline powder, relative density is 1.4. Soluble in water (when 20°C, 54g/100ml water; when 100°C,81.7g/100ml water), acidic aqueous solution. Soluble in glycerine, slightly soluble in ethanol. Moisture easily decomposed, exposed in the air easily oxidized into sulfate. Exposure to emit sulfur dioxide and acid generated the corresponding salts. Heated to 150°C decomposition.
Sodium Metabisulfite Specifications
Specification:Quality Standard（GB1886.7-2015）
| Items | Company Standard |
|---|---|
| Assay(as Na2S2O5) % ≥ | 96.5 |
| Fe % ≤ | 0.003 |
| Clarity | Clear |
| As %≤ | 1.0 |
| Heavy metals (Pb) % ≤ | 5.0 |
Sodium Metabisulfite Application
Pharmaceutical industry for the production of chloroform, benzene, styrene sulfone, and formaldehyde.
Rubber industry as a coagulant. Bleached cotton printing and dyeing industry as the dechlorination agent, and cotton scouring agent.
The leather tanning industry for processing makes the leather soft, plump, tough, waterproof, bending, wear and other properties.
The chemical industry for the production of vanillin hydroxyl, hydroxylamine hydrochloride, and so on. Sensitive industries such as reagents.
The food industry as a bleaching agent, preservative, leavening agent antioxidant, color agent and insurance agent. According to China GB2760-86 provides that: as a preservative for wine, the greatest use of 0.25g/kg; as a bleaching agent for glucose, sugar bamboo, rattan, and other mushrooms, no more than 0.45g/kg; residue (SO2 total), bamboo shoots, mushrooms are not allowed more than 0.025.