Sodium bisulfite

Sodium bisulfite

Colorless to yellowish liquid ( exists only in solution)

Only in solution resistant

Attention

1540 mg · kg -1 ( LD50, rat, oral)

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Sodium bisulfite ( NaHSO3 ), also sodium is a sodium salt of sulphurous acid. It is not stable outside of aqueous solutions.

Representation

An aqueous solution of sodium gives sodium bisulfite.

Conduct sulfur dioxide through a solution of sodium carbonate also gives sodium bisulfite.

Properties

Commercially it is prepared as a solution lying 37-50 % content of sodium bisulfite. These solutions have corrosive, reducing and strong bleaching properties. At the concentration of the aqueous solution is formed sodium metabisulfite ( Na2S2O5 ) and sodium sulfite.

Of importance is the addition reaction with aldehydes or ketones to form the so-called Hydrogensulfitaddukten ( bisulfite adducts ), wherein the sulfur of the Hydrogensulfitions nucleophile attaches to the carbonyl group to form a Hydroxyalkylsulfonations. As an example, the reaction is demonstrated with formaldehyde to form the sparingly soluble Natriumhydroxymethylsulfonats:

The bisulfite addition is often used for the purification of aldehydes or ketones, because it is reversible under basic or acidic conditions.

Use

As a food additive E 222 is using sodium bisulfite as a preservative, an antioxidant and as a stabilizer in food products, as well as for the analysis of methylation patterns in DNA.