A Simple Generic Model for Estimating Saturated Vapour Pressure

Arguably, the most important of the basic thermodynamic properties of fluids, vapour pressure has been the focus of investigation for over a century. The two main drawbacks of the models currently used for its correlation are that they either exhibit large deviations near critical temperature and triple point or that they have a large number of compound-specific adjusted parameters; hence the inconvenient necessity of having at hand large tabulations of hundreds of model parameters. In this study, by employing the up and coming procedure of genetic programming, a new model, which to a large extent remedies these shortcomings, is proposed. Essentially, having only two compound-specific adjusted parameters and also using two readily available substance parameters of molecular weight and normal boiling point, ensures a high level of convenience, yet precision and applicability over a large portion of vapour-liquid coexistence curve. Concisely, a sizable database comprised of 58272 data points was gathered for 243 organic and inorganic compounds and elements belonging to a diverse set of chemical families; which was then used in both developing and validating the proposed model and reporting generic and compound/element specific adjusted parameters. AARDs of 1.47% (for a subset of 40852 data points) and 1.82% (for a subset of 17420 data points) for the general model and a slightly modified model applicable to hydrogen-bonded alcohols and phenols, respectively, are a testament to the reliability of the new proposed model.