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Wednesday, September 6, 2023

09-05-2023-2035 - draft (Sodium_metabisulfite, etc., draft)

Sodium metabisulfite
Sodium metabisulfite
Structure of sodium metabisulfite
Names
Other names
Sodium pyrosulfite
Sodium disulfite
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ECHA InfoCard 100.028.794 Edit this at Wikidata
EC Number
  • 231-673-0
E number E223 (preservatives)
RTECS number
  • UX8225000
UNII


Properties
Na2S2O5
Molar mass 190.107 g/mol
Appearance White to yellow powder
Odor Faint SO2
Density 1.48 g/cm3
Melting point 170 °C (338 °F; 443 K) decomposition begins at 150 °C
  • 45.1 g/100 mL (0 °C)
  • 65.3 g/100 mL (20 °C)
  • 81.7 g 100 mL (100 °C)
Solubility Very soluble in glycerol
Slightly soluble in ethanol
Hazards
GHS labelling:
GHS05: CorrosiveGHS07: Exclamation mark
Danger
H302, H318
P264, P270, P280, P301+P312, P305+P351+P338, P310, P330, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no code
2
0
1
NIOSH (US health exposure limits):
PEL (Permissible)
 None[1]
REL (Recommended)
 TWA 5 mg/m3[1]
IDLH (Immediate danger)
 N.D.[1]
Safety data sheet (SDS) Mallinckrodt MSDS
Related compounds
Other anions
 Sodium sulfite
Sodium bisulfite
Other cations
 Potassium metabisulfite
Related compounds
 Sodium dithionite
Sodium thiosulfate
Sodium sulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Sodium metabisulfite or sodium pyrosulfite (IUPAC spelling; Br. E. sodium metabisulphite or sodium pyrosulphite) is an inorganic compound of chemical formula Na2S2O5. The substance is sometimes referred to as disodium metabisulfite. It is used as a disinfectant, antioxidant, and preservative agent.[2] When dissolved in water it forms sodium bisulfite.

Preparation

See also: Wellman–Lord process

Sodium metabisulfite can be prepared by treating a solution of sodium hydroxide with sulfur dioxide.[3] When conducted in warm water, Na2SO3 initially precipitates as a yellow solid. With more SO2, the solid dissolves to give the disulfite, which crystallises upon cooling.[4]

SO2 + 2 NaOH → Na2SO3 + H2O
SO2 + Na2SO3 → Na2S2O5

which yields a residue of colourless solid Na2S2O5. 

https://en.wikipedia.org/wiki/Sodium_metabisulfite

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