Database Tools for Evaluating Thermophysical Property Data

Most thermophysical-property databases (TPD) provide low-level quality control checks. This manuscript focuses on additional, higher-level data evaluations made possible by the breadth of data stored in the database. For example, thermodynamic equations relate the critical point, vapor-pressure curve, enthalpy of vaporization, liquid density, and liquid and vapor heat capacities to each other. Thermodynamic consistency among these properties can be used to guide selection of the best data sets. Even more broadly, molecular structure-based trends in properties can be identified within the database, and the properties of structurally related compounds can be effectively used to discriminate among available datasets. Automated property predictions can be used in conjunction with the TPD to guide the selection of the most accurate data. These and other high-level consistency tools will be illustrated based on evaluation and quality control work associated with the DIPPR 801 TPD project for pure chemicals.