Effect of u.v. irradiation on the base-catalyzed enolization of ethyl acetoacetate in solution

The base-catalyzed enolization of u.v. irradiated solutions of ethyl acetoacetate has been studied. It was shown that the repeatedly performed photoketonization results in a gradual increase of the rate of the reverse process (enolization),'when triethylamine was used as catalyst. The enolization is a first order reaction with respect to the keto form. The rate constant depends strongly on the structure of the catalyst.