Acta Phys. -Chim. Sin. ›› 1990, Vol. 6 ›› Issue (02): 203-208.doi: 10.3866/PKU.WHXB19900214

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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

Chu De-Ying; Zhang Ying; Hu Jing-Dan; Liu Rui-Lin   

  1. Department of Chemistry, Peking University
  • Received:1988-08-08 Revised:1989-08-21 Published:1990-04-15
  • Contact: Chu De-Ying

Abstract: The densities of the mixtures of N,N-Dimethylformamide (DMF) and water(w) have been measured at ten temperatures from 278.15 K to 318.15 K with the vibra-tingtube density meter(Anton Paar Model DMA602). Then the excess molal volumes V~E of solutions and apparent and partial molal volumes of DMF over the range of mole 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-H_2O 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 the 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.