Bisulfietion

Bisulfietion is a chemical process involving the addition of a bisulfite ion (HSO3-) or sulfite ion (SO3^2-) to an organic molecule. This reaction is particularly common with carbonyl compounds, such as aldehydes and ketones. In this reaction, the nucleophilic bisulfite ion attacks the electrophilic carbon atom of the carbonyl group. The result is the formation of an adduct, often a bisulfite addition compound.

These bisulfite addition compounds are generally water-soluble and crystalline, which can be advantageous for purifying aldehydes and ketones. The reaction is typically reversible; treatment with a base, such as sodium carbonate, can regenerate the original carbonyl compound and sulfite or bisulfite. This reversibility is a key feature exploited in various chemical separations and analyses.

Bisulfietion has applications in organic synthesis, particularly for isolating and purifying aldehydes. It can also be used to protect carbonyl groups during other chemical transformations. The reaction mechanism involves a nucleophilic addition followed by proton transfer. While aldehydes are more reactive towards bisulfite addition than ketones, many ketones also form bisulfite adducts. The specific conditions, such as pH and temperature, can influence the rate and extent of the bisulfietion reaction.