Interfacial tension measurements between alpha-tocopherol and carbon dioxide at high pressures

The interfacial tension of the binary system alpha-tocopherol/carbon dioxide was measured using the pendant drop method in the pressure range between 10 and 37 MPa at nine different temperatures: 313, 333, 343, 353, 363, 373, 383, 393, and 402 K. At every interfacial tension measurement, densities of both the liquid and the supercritical gas phase were also determined as the knowledge of these values is essential for calculating interfacial tension from the shape and size of drops. The interfacial tension decreases with rising pressure at a constant temperature and increases with increasing temperature at a constant pressure. The interfacial tension was found to be mainly a function of the mutual solubility of the two system components and of the density of pure carbon dioxide.