Excess partial molar enthalpy of 1-propanol in 1-propanol–acetone (or tetramethyl urea)–H₂O at 25°C: effect of acetone (or tetramethyl urea) on H₂O

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• 作者：Chen ; Daniel H.C. ; Liu ; Allen P.C. ; Koga ; Yoshikata
• 关键词：1-Propanol&ndash ; acetone (or tetramethyl urea)&ndash ; H₂O ; Partial molar enthalpy of 1-propanol ; 1-Propanol&ndash ; 1-propanol enthalpic interaction ; Effect of acetone or tetramethyl urea on H₂O
• 刊名：Fluid Phase Equilibria
• 出版年：2001
• 出版时间：October 15, 2001
• 年：2001
• 卷：189
• 期：1-2
• 页码：31-38
• 全文大小：103 K

文摘

Excess partial molar enthalpies of 1-propanol, H_1P^E, were measured at 25°C in ternary 1-propanol–acetone (or tetramethyl urea)–H₂O, with various initial compositions of acetone (or tetramethyl urea). They were determined accurately and in small increments in mole fraction of 1-propanol. It was therefore, possible to take a derivative of H_1P^E with respect to the amount of 1-propanol, n_1P, H_1P–1P^E≡N(∂H_1P^E/∂n_1P). The changes in the mole fraction dependence of H_1P^E and hence, H_1P–1P^E caused by adding a third component, acetone or tetramethyl urea, were compared with the results of analogous earlier studies with urea and 2-propanol as a third component. The effects of acetone and tetramethyl urea were found qualitatively the same. The CH₃ group in each compound works as a typical hydrophobic moiety and enhances the hydrogen bond network of H₂O in the immediate vicinity of solute molecule (“iceberg formation”) with concomitant reduction of the hydrogen bond probability of H₂O. The CO group on the other hand, seems to reduce the degree of fluctuation in the hydrogen bond strength in the bulk H₂O away from the solute.