INTERFACIAL-TENSIONS OF THE BINARY-SYSTEMS CARBON-DIOXIDE OLEIC-ACID,CARBON-DIOXIDE METHYL MYRISTATE, AND CARBON-DIOXIDE METHYL PALMITATE AND OF THE TERNARY-SYSTEM CARBON-DIOXIDE METHYL-MYRISTATE METHYL-PALMITATE AT HIGH-PRESSURES

Interfacial tensions of the binary systems carbon dioxide-oleic acid, carbon dioxide-methyl myristate, and carbon dioxide-methyl palmitate w ere measured at 40-degrees-C, 50-degrees-C, and 60-degrees-C and at pr essures up to 175 bar. The surface tension of subcritical carbon dioxi de and the interfacial tension of the ternary system carbon dioxide-me thyl myristate-methyl palmitate at 40-degrees-C and 50-degrees-C and a t pressures up to 71 bar were also determined. Experiments were perfor med by observing the rise in a glass capillary placed inside a high-pr essure view cell. Interfacial tensions approach zero as the critical p oint of the system is attained. Higher temperatures at a given carbon dioxide concentration in the liquid phase reduce interfacial tension-t he ''temperature effect''. At constant pressure-except near the consol ute point-interfacial tension remains nearly unchanged with rising tem perature, as the ''temperature effect'' is being counterbalanced by th e ''surfactant effect'' of decreasing carbon dioxide concentration. Al l systems studied are completely wetting. The occurrence of Marangoni instabilities is discussed. The numerical results are given in full de tail.