A. Introduction

In this section we examine how to estimate vapour pressures, enthalpies of vaporisation and boiling and melting temperatures of pure fluids. These properties play an important role in the design and operation of many chemical and physical processes.

B. Vapour pressure

The work of Boublik et al. (1984) constitutes an excellent source of experimental data for more than 1,000 substances. Data are usually correlated as a function of temperature using either the Antoine equation or the more accurate Wagner equation. The Antoine equation is obtained from the Clapeyron equation and should only be used over the range of temperatures over which the coefficients A, B, and C have been determined. It is usually presented as:

\[\label{eq1} \ln(p/p^0)=A-\dfrac{B}{T+C}\,. \tag{1}\]