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Ethyl acetoacetate (EAA) is a beta-ketone ester used in food, pharmaceuticals, surface preparations, and organic synthesis. It has a fruity aroma and is used in flavor and fragrance applications. EAA is also used as an accelerator in the polymerization process and as a solvent, stabilizer, or catalyst. In laboratory research, EAA can act as a bi-dentate ligand and form coordination bonds with transition metals.
Ethyl acetoacetate (EAA) is a beta-ketone ester that contains carbon (C), hydrogen (H) and oxygen (O) and has the empirical formula C6H10O3. It can be prepared by Claisen condensation of ethyl acetate with sodium acetate or some modification of this procedure. Ethyl acetoacetate finds several important applications, both commercial and scientific. The food industry uses it in a variety of ways, and it is used in pharmaceuticals and as an intermediate in lacquers, varnishes and other surface preparations. Research-wise, the ester is an important reagent in organic synthesis and ligand chemistry.
EAA exudes a pleasant fruity aroma. This makes it a popular synthetic for use in flavor and fragrance applications, either as-is or chemically modified, as is the case with fructon. Additionally, food manufacturers use the substance in resinous and polymeric coatings. Such coatings may be used on food contact equipment or surfaces, or may be used to a limited extent in the food itself.
Ethyl acetoacetate can be used in non-food related surface coatings or fabrics as an accelerator in the polymerization process. Referred to as promoter or co-promoter, approximately 1-3% EAA is added by weight to the unsaturated polyester resin. In other products, EAA can be added as a solvent, stabilizer or catalyst. When more extensively modified, acetoacetic acid derivatives find applications in dyes, pigments, and agrochemicals. Acetoacetoxyethyl methacrylate is used in copolymerization to reduce viscosity in adhesives.
Laboratory research has continued to reveal new substances and applications for ethyl acetoacetate. The molecule actually exists in two forms, one “enol” form, the other “keto” form, the form usually drawn to identify the molecule. These two forms can be interchanged. This property is called keto-enol tautomerism. In its enol form, EAA can act as a bi-dentate ligand, meaning that each molecule can act like a pair of crab claws ready to attack an atom, usually of a transition metal.
The claws form coordination bonds with these atoms in their grip. An example of a coordinately bonded transition metal complex is the reaction between three molecules of EAA and a single trivalent or +3 iron atom. Another example is the reaction between a molecule of ethyl acetoacetate and n-butyl lithium in pentane. In this reaction, a six-membered ring is generated, with the lithium atom and two oxygen atoms being counted between the members of the ring. Other reaction types include those of the organic chemist, which use ethyl acetoacetate as much as any other starting material is used, when it is the tool of choice.
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