Determination of the rate of tautomerization of 1-phenylbutane-1,3-dione (benzoylacetone) using the technique of solubilization into micelles

Abstract

The distribution constant and the rate of keto–enol tautomerization of 1-phenylbutane-1,3-dione (benzoylacetone) have been measured by a new technique using micellar systems in which the dione exists mainly in its enolic form in the micelles. The tautomerization rate was obtained from the absorbance change observed when an aqueous solution of benzoylacetone was mixed with a surfactant solution above the critical micelle concentration, since the tautomerization rate is much slower than the rate of solubilization of the dione into micelles. The tautomerization rate was accelerated by base catalysts such as hydroxide and acetate ions.