DETERMINATION OF KETO-ENOL EQUILIBRIUM-CONSTANTS AND THE KINETIC-STUDY OF THE NITROSATION REACTION OF BETA-DICARBONYL COMPOUNDS

The keno-enol equilibrium constants of acetylacetone, ethyl acetoaceta te and ethyl benzoylacetate in water at 25 degrees C are determined by studying the influence of surfactants on their UV-VIS spectra, follow ing the method applied to benzoylacetone published recently. These mea sured equilibrium constants are used to obtain the reactivity of the k etones towards several nitrosating agents. For this end, the nitrosati on reaction of benzoylacetone, acetylacetone, ethyl acetoacetate and e thyl benzoylacetate are studied in aqueous acidic solution in the pres ence and absence of Cl-, Br- or SCN-. Analysis of the kinetic data ind icates that the rate-limiting step is, in every case, the reaction of the enol.