Excess molar enthalpies of N,N-dimethylformamide with ketones at 298.15 K

Excess molar enthalpies (H-E) at 298.15 K of N,N-dimethylformamide with a s eries of ketones: methyl ethyl ketone (MEK), methyl propyl ketone (MIPK), d iethyl ketone (DEK), methyl isobutyl ketone (MIBK), cyclopentanone (CP) and cyclohexanone (CH) have been measured by using a Parr 1451 solution calori meter, as a function of mole fraction of the N,N-dimethylformamide. The exp erimental H-E values are positive for ail binary mixtures over the entire r ange of composition. The excess enthalpies of the above mentioned binary sy stems, were used to discuss interactions between the ketonic (>CO) and DMF molecules. The results are interpreted to gain insight into the changes in molecular association equilibria and structural effects in these systems. W hen the compounds are mixed, the changes that occur in association equilibr ia are evidently rupture of the hydrogen bonds in pure compounds and the fo rmation of OH... CO hydrogen bonds between the compounds. (C) 1999 Elsevier Science B.V. All rights reserved.