Experimental and computational (AM1, MNDO, PM3) studies on the hydrolysis rates of ethylene ketals in 1,3-cyclohexanediones

The relative hydrolysis rates of cyclohexanone ethylene ketals having different substituents at theβ- carbon, such as H2, (OCH2)2, (SCH2)2, =O, were determined at 20°C in aqueous H2SO4-silica gel-CH2Cl2 medium. The observed kinetic trend of H2>(OCH2)2>(SCH2)2>=O is correlated with calculated ΔH values (AM1, MNDO and PM3) for the ionisation ofβ-substituted cyclohexanes to the corresponding cations.