A re-appraisal of the concept of ideal mixtures through a computer simulation study of the methanol-ethanol mixtures

Martina Požar (1, 2) , Bernarda Lovrinčević (1) , Larisa Zoranić (1) , Marijana Mijaković (1) , Franjo Sokolić (1) , Aurélien Perera (2)

1 University of Split
2 LPTMC - Laboratoire de Physique Théorique de la Matière Condensée

Methanol-ethanol mixtures under ambient conditions of temperature and pressure are studied by computer simulations, with the aim to sort out how the ideality of this type of mixtures differs from that of a textbook example of an ideal mixture. This study reveals two types of ideality, one which is related to simple disorder, such as in benzene-cyclohexane mixtures, and another found in complex disorder mixtures of associated liquids. It underlines the importance of distinguishing between concentration fluctuations, which are shared by both types of systems, and the structural heterogeneity, which characterises the second class of disorder. Methanol-1-propanol mixtures are equally studied and show a quasi-ideality with many respect comparable to that of the methanol-ethanol mixtures, hinting at the existence of a super-ideality in neat mono-ol binary mixtures, driven essentially by the strong hydrogen bonding and underlying hydroxyl group clustering.

Domaines: Chimie-Physique [physics.chem-ph]; Chimie théorique et/ou physique

Martina Požar, Bernarda Lovrinčević, Larisa Zoranić, Marijana Mijaković, Franjo Sokolić, et al.. A re-appraisal of the concept of ideal mixtures through a computer simulation study of the methanol-ethanol mixtures. Journal of Chemical Physics, 2016, 145 (6), pp.064509. ⟨10.1063/1.4960435⟩. ⟨hal-01379057⟩