3-Heptanone (butyl ethyl ketone), is a seven carbon ketone. It is a colourless liquid with a "green odour," also described as having a fruity scent and a melon-banana flavour. It is often used as a perfume/fragrance, as a solvent for cellulose, nitrocellulose, or vinyl resins, and as a synthetic building block in the preparation of other organic molecules.
3-Heptanone is produced industrially through reductive condensation of propionaldehyde (propanal) with butanone (methyl ethyl ketone). This reaction yields hept-4-en-3-one, which is subsequently hydrogenated to 3-heptanone.