Interfacial activity of 2-cthylhcxanoylbcn/oyl methane is discussed in systems containing hydrocarbon diluents. Semiempirical self-consistent field calculations arc used to study the structure of β-diketones and its monohydrates in gas phase. These calculations arc in a qualitative agreement with interfacial tension studies and suggest a well-organi/ed structure of 2-clhyIhcxanoy(benzoyl methane for adsorption and interfacial reaction in extraction systems.