The effective combination of thermodynamic studies and calculations for a series of cyclic ketones and other carbonyl compounds

We describe a unique quantitative method to measure hydration equilibrium constants and enthalpy changes. The hydration of acetone and a series of cyclic ketones from cyclopropane to cycloctanone were experimentally and theoretically investigated. Molar reactions, equilibrium constants and enthalpy changes for the hydration reaction were quantitatively determined by combining refractive index and density measurements with the equilibrium expression and the Lorentz-Lorenz reactive index mixture rules. In addition, we employed molecular mechanics calculations using the MMX force field and implemented a group transfer approach to both predict the enthalpies of formation for the hydration reaction and assist our understanding of the factors that govern thermochemistry and chemical equilibria of the aforementioned carbonyl compounds. Analyses of theoretical calculations infer that the hydration enthalpies and equilibria are influenced by the degree of ring strain, bond bending, bond eclipsing, torsional, steric, and inductive effects of alkyl groups, hybridization changes, dipole moment, and hydrogen bonding.