Second virial coefficient of benzene and its temperature derivatives

Abstract

An analysis of the experimental second virial coefficients, isothermal Joule–Thomson coefficients and pressure coefficients of the heat capacity of benzene vapour has been carried out. A preliminary examination shows that the second virial coefficient data and the pressure coefficient of the heat capacity data are thermodynamically consistent within the experimental error on the measurements, but the isothermal Joule–Thomson coefficient data are not. Inspection of the experimental Joule–Thomson coefficients shows them to contain an internal thermodynamic inconsistency. On the basis of previous experience the error in the measurements was attributed to the presence of a heat leak in the calorimeter used for the experiments. Analysis of this heat leak allows a correction to be applied to the isothermal Joule–Thomson coefficients. The corrected coefficients are in excellent agreement with the second virial coefficients and the pressure coefficients of the heat capacity. An empirical equation which represents the whole of the three sets of data over the temperature range 290 to 660 K is generated.