Miki Kumiko, Westh Peter, Nishikawa Keiko, Koga Yoshikata
Department of Liberal Arts and Basic Sciences, College of Industrial Technology, Nihon University, Narashino, Chiba 275-8575, Japan.
J Phys Chem B. 2005 May 12;109(18):9014-9. doi: 10.1021/jp046309c.
The excess partial molar enthalpy of 1-propanol (1P), , was measured at 28 degrees C in the ternary mixture of 1P-1-butyl-3-methylimidazolium chloride ([bmim]Cl)-H(2)O in the H(2)O-rich composition range. From these data we evaluated what we call the 1P-1P enthalpic interaction function, . Its changes induced by addition of [bmim]Cl of the pattern of were used as a probe to elucidate the effect of [bmim]Cl on the molecular organization of H(2)O. It was found that the effect of Cl(-) was not conspicuous within this methodology, and the observed dependence is predominantly due to the hydration of bmim. The changes in the x(1P)-dependence of were compared with those brought about by temperature increase, or by the addition of fructose or glycerol. It was found that the effect of bmim is similar to that of fructose or increased temperature. We speculate that in the H(2)O-rich composition region a number of H(2)O molecules are attracted to the delocalized positive charge of the imidazolium ring and the bulk of H(2)O is influenced in such a manner that the global hydrogen bond probability is reduced.
