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Study of self-diffusion in two binary solutions, glycerol-water and methanol-water using diffusion-ordered spectroscopy

Fadaei, E ; Sharif University of Technology

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  1. Type of Document: Article
  2. Publisher: Sharif University of Technology
  3. Abstract:
  4. The concentration and temperature behaviors of the self-diffusion coefficient were analyzed in glycerol-water and methanol-water solutions using Diffusion-Ordered Spectroscopy (DOSY) experiment. Our results indicate that the self-diffusion coefficient dips with increasing concentration and decreasing temperature. The concentration behavior shows that there is hydrogen bond interaction between water and alcohol, which declines the self-diffusion coefficients of both in the aqueous binary mixtures. The self-diffusion activation energies were estimated 13.6, 29.4, and 32.8 (kJ/mol) for methanol and 24.8, 25.5, and 27.6 (kJ/mol) for water in the methanol-water solutions with 0.03, 0.10, and 0.20 mole fractions of methanol, respectively. The methanol self-diffusion activation energy, in the very dilute methanol-water solution (0.03 mole fraction of methanol), is consistent with the formation of iceberg-like structure which helps methanol to diffuse quickly. The water self-diffusion activation energies indicate that water network is not significantly perturbed by methanol and the water molecules diffuse in the same manner in methanolwater solutions
  5. Keywords:
  6. Temperature effect ; Activation energy ; Binary mixtures ; Bins ; Chemical activation ; Diffusion in liquids ; Glycerol ; Hydrogen bonds ; Methanol ; Molecules ; Sea ice ; Temperature ; Thermal effects ; Concentration effects ; Diffusion ordered spectroscopies ; DOSY NMR ; Hydrogen bond interaction ; Self-diffusion ; Self-diffusion activation energy ; Self-diffusion coefficients ; Water self diffusions ; Diffusion
  7. Source: Scientia Iranica ; Volume 23, Issue 3 , 2016 , Pages 1175-1183 ; 10263098 (ISSN)
  8. URL: http://scientiairanica.sharif.edu/article_2196.html