Keto-enol equilibrium constants of simple monofunctional aldehydes and ketones in aqueous solution

Article abstract of DOI:10.1021/ja00168a035

Keto-enol equilibrium constants, K_E, were determined for five aliphatic ketones (2-butanone, 3-methyl-2-butanone, 3,3-dimethyl-2-butanone, 3-pentanone, and 2,4-dimethyl-3-pentanone) and three alicyclic ketones (cyclopentanone, cyclohexanone, and cycloheptanone) in aqueous solution at 25°C by combining acid-catalyzed enolization and ketonization rate constants according to the relationship K_E = k_E/k_K. Enolization rate constants were measured by halogen scavenging and ketonization rate constants were measured by monitoring the decay of enols generated flash photolytically through photooxidation of the corresponding alcohols. The effects of structure on K_E. k_E, and A_K are discussed.