ENTHALPIES OF INTERACTION OF ALIPHATIC-KETONES WITH POLAR AND NON-POLAR SOLVENTS

Solvation enthalpies [ΔH(v → S)] of a variety of aliphatic ketones including straight-chain, branched, and cyclic compounds have been determined in methanol, dimethylformamide, benzene, and cyclohexane by combining measurements of the heats of solution (ΔHs) and heats of vaporization (ΔHv). Values of A HK have been determined by the gas chromatography-calorimetry method, and several of the calculated liquid heat capacities required by this procedure have been verified by experimental measurement. ΔH(v → S) for most ketones are in the order benzene (most exothermic) > DMF > MeOH > c-C6H12. Comparison of ΔH(v → S) values for ketones with values for hydrocarbons of the same carbon skeleton provides a measure of polar interactions of the ketones with solvents. These interactions are largest for the cyclic and 2-ketones, less for the straight-chain symmetrical ketones, and least for the highly branched 2, 2, 4, 4-tetramethyl-3-pentanonc, and decrease with increasing ketone size within each group. © 1979, American Chemical Society. All rights reserved.