This Study evaluates the accuracy of different analytical EOS models in predicting isochoric heat capacity experimental data, a subject that has not received major attention so far, Contributions of the temperature dependency for the cohesive parameter, the Dieterid's and the expression derived for the description of association empirically attached to a generalized van der Waals-like equation, have been considered. It has been found that the temperature dependency of the cohesive parameter may improve the performance of the model at low temperatures and the expression derived for the description of association may qualitatively improve the description of the trend of the data near the critical temperature. None of the analyzed models can describe the behavior of the data at very high pressures. (c) 2008 Elsevier B.V. All rights reserved.