Excess enthalpies of dimethyl sulphoxide with chloroform, carbon tetrachloride, and benzene

Abstract

The molar excess enthalpies (molar enthalpies of mixing) of dimethyl sulphoxide with chloroform, carbon tetrachloride, and benzene have been measured at 298.15 and 308.15 K. The values for the equimolar mixtures at 298.15 K are −2.83 kJ mol −1 , 181 J mol −1 , and 586 J mol −1 , respectively. For chloroform + dimethyl sulphoxide the molar excess enthalpy at 298.15 K has a minimum of −3.00 kJ mol −1 at mole fraction 0.40 of dimethyl sulphoxide and the molar excess heat capacity at constant pressure is positive. For carbon tetrachloride + dimethyl sulphoxide the molar excess enthalpy at 298.15 K has a maximum of 297 J mol −1 at mole fraction 0.21 of dimethyl sulphoxide and the molar excess heat capacity at constant pressure is positive. For benzene + dimethyl sulphoxide the molar excess enthalpy is nearly symmetrical in mole fraction and the molar excess heat capacity at constant pressure is small and negative. The results are compared with previous measurements and discussed in terms of complex formation in solution.