β-DIKETONE INTERACTIONS Part 5. Solvent effects on the keto enol equilibrium

Article abstract of DOI:10.1016/0022-2860(87)85074-3

The keto <*> enol equilibrium of pentane-2,4-dione (PD) has been measured in 21 solvents at infinite dilution and a linear free energy relationship (LFER) tested againts four solvent polarity vectors: ε, E_T, ?^* and A + B.The best correlation coefficient is found for A +B.Similarly 3-methyl-pentane-2,4-dione (MePD) has been studied in 14 solvents and 3-ethylpentane-2,4-dione (EtPD) in six.The results suggest that the cyclic hydrogen bonding of the enol remains intact in all the solvents studied.