Study of self-di ffusion in two binary solutions, glycerol-water and methanol-water using diff usion-ordered spectroscopy

Authors

Department of Chemistry, Sharif University of Technology, Tehran, P.O. Box 11155-9516, Iran.

Abstract

The concentration and temperature behaviors of the self-diff usion coecient were analyzed in glycerol-water and methanol-water solutions using Di usion-Ordered Spectroscopy (DOSY) experiment. Our results indicate that the self-di usion coecient 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-diff usion coecients of both in the aqueous binary mixtures. The self-diff usion 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-di usion 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 di use quickly. The water self-diff usion activation energies indicate that water network is not signi cantly perturbed by methanol and the water molecules di use in the same manner in methanolwater solutions.

Keywords

Scientia Iranica
Volume 23, Issue 3 - Serial Number 3
Transactions on Chemistry (C)
June 2016
Pages 1175-1183

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