Thermal polymerisation and autoxidation of technical grade linoleic acid

Oligomerisation of technical grade linoleic acid was studied over a broad temperature range. Effects of water and air were specifically addressed. The products were analysed by size-exclusion chromatography to give directly the concentrations of dimers and trimers. Oligomerisation of technical grade linoleic acid was seen to be dependent on temperature and the activation energy for monomer disappearance was 109 kJ/mol. A phenomenological kinetic model was proposed for the linoleic acid oligomerisation giving good model predictions. The presence of water inhibited the oligomerisation reaction. Extensive dimerisation and trimerisation occurred under a continuous air flow, whereas introduction of air pulses resulted in only a minor enhancement of trimerisation.