3Hydroxybutanone

3-Hydroxybutanone, commonly known as acetoin, is an organic compound with the formula C4H8O2. It features a carbonyl group (ketone) at carbon 2 and a hydroxyl group at carbon 3, giving the structure CH3-CO-CH(OH)-CH3. The molecule is chiral at the C3 position, so it exists as two enantiomers (R and S) or as a racemate.

Acetoin occurs naturally in various fermented foods and is produced by several microorganisms during carbohydrate metabolism, particularly via the acetoin/2,3-butanediol pathway. It is associated with dairy products, sourdough, and other fermented foods and is commonly detected in microbiology by the Voges-Proskauer test, which detects acetoin.

Industrially, 3-hydroxybutanone can be prepared by chemical synthesis or by biotechnological fermentation. It is valued as a flavor additive, imparting a mild buttery aroma, and serves as an intermediate in the synthesis of pharmaceuticals and fragrances. In metabolism, it can be interconverted with related compounds such as 2,3-butanediol, depending on cellular conditions and enzyme availability.

Safety and handling: acetoin is used in small quantities as a food flavoring agent and should be handled with standard laboratory precautions. It can act as an irritant to skin and eyes and may cause respiratory irritation in some individuals; appropriate protective equipment and ventilation are advised when handling concentrated material.