Hydration free energy difference of acetone, acetamide, and urea

P. Jedlovszky, Abdenacer Idrissi

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The hydration free energy and hydration entropy difference of urea and acetone, and of acetamide and acetone have been calculated both by free energy perturbation and by the method of thermodynamic integration. The obtained results show a striking asymmetry between the thermodynamic changes accompanying the replacement of the first and second C H3 group of acetone by N H2. Thus, the first C H3 N H2 exchange is found to lead to an about 10 kJmol decrease in the energy, 8 kJmol decrease in the Helmholtz free energy, and 5-10 Jmol K decrease in the entropy of hydration, while similar values accompanying the second C H3 N H2 exchange are found to be about -65 kJmol, -35 kJmol and -100 Jmol K, respectively. These results indicate that the two N H2 groups of the urea molecule have a strong synergetic effect on the thermodynamics of the hydration of urea. The fact that the replacement of the two C H3 groups of acetone by N H2 leads to a strong decrease in the hydration entropy indicates that urea clearly has an ordering effect on nearby water.

Original languageEnglish
Article number164501
JournalThe Journal of Chemical Physics
Volume129
Issue number16
DOIs
Publication statusPublished - 2008

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Acetone
ureas
Hydration
acetone
Free energy
hydration
Urea
Entropy
free energy
Thermodynamics
entropy
thermodynamics
acetamide
asymmetry
Water
perturbation
Molecules
water
molecules
energy

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry
  • Medicine(all)

Cite this

Hydration free energy difference of acetone, acetamide, and urea. / Jedlovszky, P.; Idrissi, Abdenacer.

In: The Journal of Chemical Physics, Vol. 129, No. 16, 164501, 2008.

Research output: Contribution to journalArticle

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