Acetylacetone

Acetylacetone is an organic compound with the chemical formula (CH₃CO)₂CH₂. It is the simplest β-diketone, meaning it has two C=O functional groups that are separated by one carbon atom (a methylene bridge).

Most ketones show tautomerism: the molecules change back and forth between two different chemical structures. Ketones have both the ketone form, where the double bond is between carbon and oxygen, and an enol form where the double bond is between two carbon atoms.

While usually the ketone form is more stable, pure acetylacetone is more stable as the enol. When in a solution, the form depends on the solvent, with more ketone found in more polar solvents.^[1]

Acetylacetone is a weak acid. Its conjugate base, acetylacetonate, has resonance between the carbon-oxygen bonds and the central carbon-carbon bonds, which helps stabilise the anion.

Acetylacetonate is a bidentate ligand, forming coordination complexes called metal acetylacetonates.

Acetylacetone can be prepared by many routes. Industrially, it is made by rearrangement of isopropenyl acetate.^[2] In the laboratory, it can be made from acetone by multiple routes: a reaction with acetic anhydride and a Lewis acid like boron trifluoride, or a reaction with ethyl acetate and an alkoxide base like sodium ethoxide via an enolate intermediate.^[3]