This paper focuses on the solute – solute interactions in dilute solutions of a typically hydrophobic solute tetramethylurea (TMU) in ethylene glycol (EG) which forms the three-dimensional hydrogen-bond network at the supramolecular level. The results of our experimental efforts based on dilution calorimetry and phase partition techniques are able to make a conclusion that thermodynamics of the TMU – TMU pairwise interaction in EG is to a great extent similar to that occurs in liquid water. All effects, however, are weaker expressed in the non-aqueous medium. In particular, the integrand of the potential of mean force, i.e. the second virial coefficient, between two TMU molecules becomes negative only at elevated temperatures indicating the appearance of a rather weak solvophobic interaction in EG. Since C=O-groups of TMU are well-incorporated into the H-bond network of EG, it is reasonable to assume that the attraction observed should be mainly induced by apolar methyl groups. The correlation between the enthalpy- and volume-related parameters of pairwise interaction provides the additional confirmation of the existence of the solvent-induced solvophobic interaction between TMU molecules in EG.

本文重点研究在乙二醇（EG）中典型的疏水性溶质四甲基脲（TMU）的稀溶液中的溶质-溶质相互作用，该溶液在超分子水平上形成三维氢键网络。我们基于稀释量热法和相分配技术的实验结果可以得出结论：EG中TMU – TMU成对相互作用的热力学在很大程度上与液态水相似。但是，在非水介质中所有作用均较弱。特别是，平均力势的整数，即仅在升高的温度下，两个TMU分子之间的第二病毒系数才变为负值，表明EG中出现了较弱的疏溶剂相互作用。由于TMU的C = O-基团很好地结合到EG的H键网络中，因此可以合理地假设观察到的吸引力应主要由非极性甲基诱导。成对相互作用的焓和体积相关参数之间的相关性进一步证实了EG中TMU分子之间存在溶剂诱导的疏溶剂相互作用。