Isothermal solid-liquid equilibrium for three binary systems of oleic acid, linoleic acid and α-linolenic acid under high pressure

Abstract

A new method for determining the liquidus and solidus pressures of mixtures of C18′s unsaturated fatty acids at constant temperatures was proposed, and three binary isothermal SLE data under high-pressure were systematically measured in this study. The liquidus and solidus temperatures of oleic acid, linoleic acid and α -linolenic acid commonly rise above their normal melting temperatures when pressure is increased. This new high-pressure experimental system can closely track pressure in real time during pressure swinging changes, making it simple to measure liquidus and solidus pressures using this dynamic measurement method due to fast responsiveness of pressure. In this study, the liquidus pressures of pure oleic acid, linoleic acid, α -linolenic acid and three binary mixtures consisted of oleic acid, linoleic acid α -linolenic acid at constant temperature were determined. The isothermal SLE were first correlated based on a simple thermodynamic model.