Excess Heat Capacities of Binary Mixtures Containing o-Chlorotoluene and Pyridine or Isomeric Picolines or Aromatic Hydrocarbons

The excess molar heat capacities, CPE12\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \left( {C_{{P}}^{\text{E}} } \right)_{12} $$\end{document}, of binary mixtures of o-chlorotoluene (1) with pyridine, α-, β- or γ-picoline, benzene, toluene or o-xylene (2) have been measured as a function of composition at 298.15, 303.15 and 308.15 K using a micro differential scanning calorimeter (Model-μDSC 7 Evo). The CPE12\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \left( {C_{{P}}^{\text{E}} } \right)_{12} $$\end{document} data have been fitted with the Redlich–Kister equation to calculate binary adjustable parameters along with standard deviations. The sign and magnitude of values of o-chlorotoluene (1) + pyridine or α- or β-picoline (2) are dictated by the relative proportion of components in the mixtures. However CPE12\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \left( {C_{{P}}^{\text{E}} } \right)_{12} $$\end{document} values for o-chlorotoluene (1) + γ-picoline (2) mixture are positive and CPE12\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \left( {C_{{P}}^{\text{E}} } \right)_{12} $$\end{document} values for o-chlorotoluene (1) + benzene or toluene or o-xylene (2) mixtures are negative over the entire mole fraction range. The topology of the constituent molecules has been employed (Graph theory) to determine the CPE12\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \left( {C_{{P}}^{\text{E}} } \right)_{12} $$\end{document} data of the studied mixtures. It has been observed that CPE12\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \left( {C_{{P}}^{\text{E}} } \right)_{12} $$\end{document} values obtained by Graph theory are in agreement with the experimental values.