The keto-enol equilibrium of acetylacetone, benzoylacetone and dibenzoylmethane in various polar and non-polar solvents have been calculated using IR technique. Substitution of methyl group by phenyl group in acetylacetone shifts the equilibrium towards the enol form due to increase of resonance energy of the enol form and therefore dibenzoylmethane is completely enolized, the enol content increases as the polarity of the solvent decrease. The band at 1695 cm-1 in the spectrum of acetylacetone relatively various with solute concentration in non-polar solvent. This band attributes to the presence of small amount of non-chelated enol molecules which are absent in the other two compounds.
N A ABOOD ,A F AJAM ,
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