Sodium bisulfite is a colorless crystal with the chemical formula of NaHSO3. It is commonly used in food, medicine, cosmetics and other industries as a preservative, bleaching agent, antioxidant, etc. Sodium metabisulfite, on the other hand, is a product of sodium bisulfite under certain conditions, which has stronger bleaching and bactericidal effects.

Sodium bisulfite can be prepared through various methods, one of which is commonly used by reacting sodium sulfite with sulfuric acid. The reaction formula is Na2SO3+H2SO4→ 2NaHSO3. The sodium bisulfite prepared by this method usually contains a certainamount of sodium sulfite and sulfuric acid, which require further purification to obtain high-purity sodium bisulfite.

How Does Sodium Bisulfite Generate Sodium Metabisulfite

To prepare sodium metabisulfite, it is necessary to heat it at high temperature to decompose it into sodium metabisulfite and sulfur dioxide. The reaction formula is 2NaHSO3→ Na2S2O5+SO2+H2O. This reaction needs to be carried out at a high temperature above 300 ℃, and the reaction time and conditions need to be controlled to avoid the generation of other by-products.

Sodium metabisulfite is a white crystal with chemical formula of Na2S2O5, which has stronger bleaching and bactericidal effects. It can be used to bleach materials such as paper, fabrics, leather, and can also be used as a preservative, bleach, antioxidant, etc. in industries such as food, medicine, and cosmetics. Compared with sodium bisulfite, sodium metabisulfite has a better bleaching effect and is also more stable and less prone to decomposition.

Sodium metabisulfite and sodium bisulfite are important chemicals that are widely used in industrial production and daily life. By preparing sodium bisulfite and further decomposing it to obtain sodium metabisulfite, it can meet the needs of different fields for bleaching, sterilization, anti-corrosion, and other aspects.