Excess enthalpies of dimethylsulfoxide with substituted benzenes at 298.15 K

Excess molar enthalpies (HE) at 298.15 K have been measured by a Paar 1451 solution calorimeter as a function of composition for the binary liquid mixtures of dimethylsulfoxide (DMSO) with substituted benzenes. The substituted benzenes include toluene, ethylbenzene, chlorobenzene, bromobenzene and nitrobenzene. The HE values for the above mixtures are all positive over the entire composition range. The experimental results have been correlated using the Redlich–Kister (R–K) polynomials. The results are interpreted on the basis of possible hydrogen bonding between unlike molecules and changes in molecular association equilibria as well as structural effects for these systems. The excess enthalpy data have also been correlated with the Peng–Robinson (PR) as well as the Patel–Teja (PT) equations of state (EOS) and also the activity coefficient models of the Wilson and the NRTL.