2.2. Multi-component mixture of fatty acids and key compounds
Free fatty acids are the main components of palm fatty acid
distillates (99 wt.% fatty acids palmitic + oleic + linoleic, 0.9 wt.%
squalene, and 0.1 wt.% tocopherols), thus palm fatty acid distillates
have been considered as a mixture consisting of palmitic,
oleic and linoleic acids. Fatty acids are compounds of a homologous
series (carboxylic acids). Palmitic acid differs from oleic and
linoleic acids only by carbon chain length and number of double
bonds. The separation of palmitic/oleic + linoleic acids from palm
fatty acid distillates in countercurrent columns using supercritical
carbon dioxide as the solvent is based on the difference in
the carbon chain length between palmitic (C15H31CO2H) and oleic
(C17H33CO2H) + linoleic (C17H31CO2H) acids. Because of this issue,
palm fatty acid distillates can be easily reduced to a quasi-binary
system consisting of two pseudo and or key compounds as follows:
palmitic acid (light component) and oleic + linoleic acids (heavy
component).