fatty acids (Figure 4). In this case the reaction mixture consists only of epoxidized
triglycerides and epoxidized free fatty acids, and in contrast to mono- and diglycer-
ides the free fatty acids can be easily removed afterwards, e.g. by an alkaline wash-
ing. Of course, this procedure involves some interesterification; to avoid any change
in fatty acid distribution, the free fatty acids should be of the same composition as the
triglyceride used.
Several plant oils were epoxidized this way (Table 2) with yields of 88–96 % and
a selectivity of 84–100 %. Even in the case of highly unsaturated linseed oil, very
good yields are obtained and the selectivity remains high; thus, without any further
work-up the product has superior quality compared to commercial samples.
Using controlled partial epoxidation, it is possible to prepare substitutes that mi-
mic the properties of natural epoxy oils such asvernoniaoil (Ru ̈sch gen. Klaas and
Warwel, 1999b). These are not yet available commercially, but may have some in-
teresting applications as a reactive diluent for paints. Rapeseed fatty acid methyl-
122 7 Lipase-Catalyzed Peroxy Fatty Acid Generation and Lipid Oxidation
Figure 4. Chemo-enzymatic ‘self’-epoxidation of unsaturated plant oils by NovozymÒ435/H 2 O 2 with
addition of free fatty acids.