Vapor Pressures from a Corresponding-States Principle for a Wide Range of Polar Molecular Substances

Abstract

In this work, the performance of equations that describe vapor-pressure behavior over the entire region from the triple point to the critical point is surveyed and compared. The vapor pressures of highly nonspherical molecules are considered, and the performance of the recently developed general extended corresponding-states principle used with the Xiang–Tan vapor-pressure equation is demonstrated. Comparisons with highly accurate vapor-pressure data and existing models show that the method has an accuracy for a wide range of polar molecules which agrees approximately with the accuracy of highly accurate data over the entire vapor-pressure region.