Diones such as acetylacetone are commercially significant compounds. For example, acetylacetone is used as an intermediate to produce the bidentate ligand acetylacetonate (acac), which is widely used in organo-metallic catalysts. It is also used in various metal extraction processes, as an intermediate to make heterocyclic compounds, as a fuel additive, in dyes, and in metal plating processes, among other uses. The present inventors surmise that functionalized 2,4-diones will have similar commercial applications and importance as acetylacetone. Thus, there is potential commercial interest in making 2,4-diones such as acetylacetone from renewable sources.
Conventionally, acetylacetone is prepared industrially by the thermal rearrangement of isopropenyl acetate:
This is a multistep process starting with a reaction of acetone and ketene (both of which are derived from non-renewable petroleum feedstock) to yield the isopropenyl acetate. The subsequent rearrangement reaction is conducted at high temperature (typically 500° C. to 600° C.) over a metal catalyst, to yield the acetylacetone product.
Acetylacetone can also be made in laboratory quantities using acetone, acetic anhydride, and BF3 as a catalyst:

An alternative route involves the base-catalyzed condensation of acetone and ethyl acetate, followed by acidification.
Witter et al. describe a colorimetric assay for measuring acetylacetone that uses 1,2-diaminobenzene (i.e., o-phenylenediamine) as a binding partner. The resulting compound has a distinct reddish-purple color. See Witter et al. (1948) “Colorimetric Determination of Acetylacetone and Related β-Diketones,” J. Biol. Chem. 176:485-492. The authors note that triacetic lactone will not bind with the 1,2-diaminobenzene, but that triacetic lactone can be converted to acetylacetone by hot acid hydrolysis. The acetylacetone so formed, however, must be simultaneously distilled from the boiling reaction mixture.
While these routes are straightforward, the required reactants (acetone, ethylacetate, and isopropenylacetate) are currently available solely from non-renewable, petroleum-based feedstock. Therefore, there remains an unmet need for a method to fabricate 2,4-diones such as acetylacetone in high yield from a renewable feedstock.