EXCESS MOLAR VOLUMES OF MIXTURES OF N,N-DIMETHYLFORMAMIDE AND WATER AND APPARENT MOLAL VOLUMES AND PARTIAL MOLAL VOLUMES OF N,N-DIMETHYLFORMAMIDE IN WATER FROM 278.15 K TO 318.15 K

The densities of the mixtures of N,N-Dimethylformamide (DMF) and water(w) have been measured at ton temperatures from 278.15K to 318.15K with the vibratingtube density meter(Anton Paar Model DMA602). Then the excess molal volumes V-m fraction 0-1 have been determined. Comparing these quantities as functions of mole fraction of mixtures with the standard entropies of transfer for NaCl from water to DMF-H2O mixtures as function of mole fraction of mixed solvent we found out there is a correspondence between the V-DMF varied with x and the standard entropies of transfer of NaCl. Both have extremes at x = 0.075. Therefore the structure of solution have been discussed. It might be considered that monomeric DMF molecules have been trapped in a quasi-clathrate "cage" made up of 12 water molecules at x = 0.075 forming the possible closest packing of particles.