Sodium bisulfite (chemical formula: NaHSO3), white crystalline powder, odor of sulfur dioxide, soluble in water, but also slightly soluble in alcohol. It is easily oxidized to sulfate in air. Sodium bisulfite adduct is formed by addition reaction of sodium bisulfite with active aldehydes and ketones. The reaction can be used to avoid the use of highly toxic HCN in the addition of carbonyl and HCN, by adding the carbonyl compound to sodium bisulfite, and then adding the same amount of NaCN. It can be prepared from sodium metabisulfite and water with the formula:
Na2S2O5(s)+H2O(l)→2NaHSO3(aq)
Product Name:Sodium bisulfite
CAS Number:7631-90-5
EINECS:231-548-0
Molecular Weight:104.06
Molecular Formula:HNaO3S
HS Code:28321000
Mol File:7631-90-5.mol
Synonyms:Sulfurousacid, monosodium salt (8CI,9CI);E 222;FR-62;Hydrogen sodium sulfite;Hydrogen sulfite sodium;Monosodium sulfite;Sodium acid sulfite;Sodiumbisulfite;Sodium bisulfite (NaHSO3);Sodium bisulphite;Sodium hydrogensulfite;Sodium sulfite (NaHSO3);Sodium Bisulfite;Sodium hydrogen sulfite;
Appearance and properties: white powder
Density: 1.48
Melting point: 150 °C
Refractive index: 1.43-1.47
Water solubility: 300 g/L
Stability: Stable. Incompatible with strong oxidizing agents, strong acids.
Storage conditions: warehouse ventilation low temperature dry
Production method
1. Slowly add soda ash into the mother liquor of sodium bisulfite (containing 40% NaHSO3, Ph 3 ~ 4) to generate sodium sulfite solution (the end point is when the Ph value of the slurry reaches 7 ~ 8); This sodium sulfite solution absorbs SO2 gas (10% ~ 13%) from sulfur combustion in a series reactor (2 ~ 3 pieces), reacts to produce sodium bisulfite (reaction temperature no longer rises as the end point), precipitates a large amount of crystallization during the reaction process, and centrifuges to obtain wet products containing 6% ~ 10% moisture. Then the product is dried and dehydrated by air flow at 250 ~ 300℃.
2. Put sulfur dioxide into cold sodium carbonate saturated solution, add ethanol, centrifuge and filter, and then wash and dry
with ethanol to obtain sodium bisulfite.
3. Pass SO2 into the cold sodium carbonate saturated aqueous solution until no CO2 is produced and the solution becomes
acidic. Adequate cooling and air isolation should be paid attention to during operation. A large amount of sodium bisulfite
crystals can be precipitated by adding about the same amount of ethanol to the concentrated aqueous solution prepared in the
above operation. The crystals are drained and washed with ethanol, placed on filter paper, and dried in a nitrogen stream.
4. After the reaction of sulfur dioxide gas into sodium carbonate saturated aqueous solution, it is obtained by crystallization
and dehydration.
5. Under the condition of sufficient cooling and isolation of air, the sulfur dioxide gas is passed into the cold sodium carbonate
saturated solution for reaction: When the carbon dioxide gas no longer escapes, stop passing sulfur dioxide, at this time the
solution should be acidic, if there is crystallization, it can be slightly heated to dissolve, and then add an equal volume of
ethanol to the solution, after stirring, standing, centrifugal filtration, crystallization and then washing with ethanol, centrifuge
and dry, at 250 ~ 300℃ air drying to obtain the finished product.
6. Sodium bisulfite is produced by absorbing sulfur dioxide in the tail gas of acid making with soda ash solution, centrifuge
separation, and air drying at 250 ~ 300℃ to obtain sodium bisulfite.
Use
Widely used in photographic development, food anticorrosive, organic bleaching, dyes, pharmaceuticals, paper making, leather, chemical synthesis and copper plating bath, reducing agents, pesticides, brewing beverage industry as a fungicide, can also be used in the production of saccharin, spices and hydroxylamine hydrochloride and so on.
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