Dialdehydes

Dialdehydes are organic compounds that contain two aldehyde functional groups (–CHO). They can be classified as alkanedials, with the two formyl groups located at terminal positions of a carbon chain or at internal positions along the chain. Common examples include ethanedial (glyoxal, OHC-CHO), propanedial (malondialdehyde, OHC-CH2-CHO), butanedial (succinaldehyde, OHC-(CH2)2-CHO), and pentanedial (glutaraldehyde, OHC-(CH2)3-CHO). Hexanedial (adipaldehyde) is another member in this series.

Dialdehydes are typically bifunctional electrophiles; each aldehyde group can undergo typical carbonyl reactions. They can be oxidized further to dicarboxylic acids, or reduced to corresponding diols. They readily form acetals and hemiacetals with alcohols or form imine linkages with amines, enabling crosslinking in polymers and proteins. This bifunctionality makes dialdehydes useful as crosslinking agents and fixatives.

Industrial and laboratory use: glutaraldehyde is a widely used sterilant and tissue fixative, while glyoxal has been employed as a disinfectant and preservative. Malondialdehyde is known chiefly as a biomarker for lipid peroxidation and oxidative stress in biological research.

Safety: many dialdehydes are irritants and sensitizers; handling requires appropriate protective equipment and ventilation. Glyoxal and glutaraldehyde can be hazardous, and proper storage is necessary.