Experimental and theoretical studies of the crossover behavior of the specific heat C-v,C-x of ethane, propane, and their mixture at critical isochores

The specific heat at constant volume, C-v, of propane, and mixture with a concentration of x = 0.0081 mol fraction of propane was measured along the critical isochores at temperatures between 290 and 400 K. The measurements were performed with a high-temperature constant-volume adiabatic calorimeter. The uncertainty of most of the measurements is estimated to be less than 1.5%. Measurements have been carried out in both the one- and two-phase regions. The results for the pure components are compared with earlier measurements. Crossover equations for C-v obtained on the basis of the renormalization-group method and epsilon-expansion are applied to represent our experimental specific heat data for ethane, propane, and its mixture along the critical isochores.