Diacetyl (
IUPAC systematic name:
butanedione or
butane-2,3-dione) is an
organic compound with the chemical formula (CH
3CO)
2. It is a yellow/green liquid with an intensely buttery flavor. It is a
vicinal diketone (two C=O groups, side-by-side) with the
molecular formula C
4H
6O
2. Diacetyl occurs naturally in alcoholic beverages and is added to some foods to impart its buttery flavor.