Solvent-induced frequency shifts in the infrared spectrum of acetone in organic solvents

The solvent induced frequency shifts observed in the infrared spectrum of a cetone as a dilute solute are reported for 23 organic solvents, both polar and non-polar. Both the C=O stretching frequency and the asymmetric stretch of the molecular skeleton show strong correlations with the acceptor numbe r of the solvent, a measure of its Lewis acidity. A detailed study of the a bsorption in the 1715 cm(-1) region for acetone-carbon tetrachloride and ac etone-nitrobenzene mixtures reveals the presence of three bands, one due to the acetone monomer and two due to dimers. These data are analyzed to obta in estimates of the dimerization equilibrium constant.