4. High-pressure carbon dioxide properties

### 4.1. Thermodynamic properties

The influence of the density in the solvation power by the tunable operating conditions (P, T) is the most important thermodynamic effect in the high-pressure fluid processes.

Above the critical point, the supercritical extraction process can operate over a wide range of operating conditions (P, T) and the simplest density behavior can be obtained through an isotherm, being possible to select a wide range of operating pressures, as shown in Figure 3 of the item 2.2 for the isotherms T1 > T2 > T3 > T4 > T5.

The density is defined by the inverse of specific volume, and for practical purpose, could be calculated by volumetric properties (P-V-T) using equation of state.
