Excess molar enthalpies of binary and ternary liquid mixtures

Excess molar enthalpies, H123E\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ H_{123}^{\text{E}} $$\end{document} of ternary 1-ethyl-3-methylimidazolium tetrafluoroborate (1) + 2-methyl aniline (2) + aniline or N-methyl aniline (3); 1-ethyl-3-methylimidazolium tetrafluoroborate (1) + water (2) + formamide or N,N-dimethyl formamide (3) and HE of 2-methyl aniline (1) + aniline or N-methyl aniline (2); 1-ethyl-3-methylimidazolium tetrafluoroborate (1) + formamide (2) mixtures, have been measured at 298.15 K. The excess molar enthalpies, H123E\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ H_{123}^{\text{E}} $$\end{document}, are negative for 1-ethyl-3-methylimidazolium tetrafluoroborate (1) + 2-methyl aniline (2) + aniline or N-methyl aniline (3) mixtures and are positive for 1-ethyl-3-methylimidazolium tetrafluoroborate (1) + water (2) + formamide (3) mixture over entire composition of (1) and (2) components. However, the magnitude and sign of H123E\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ H_{123}^{\text{E}} $$\end{document} value for 1-ethyl-3-methylimidazolium tetrafluoroborate (1) + water (2) + N,N-dimethyl formamide (3) mixture vary by the relative composition of the constituent molecules. The H123E\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ H_{123}^{\text{E}} $$\end{document} and HE data have also been tested in terms of Graph and Prigogine–Flory–Patterson theories.