REACTION OF ALPHA-TOCOPHEROL IN HEATED BULK PHASE IN THE PRESENCE OF METHYL LINOLEATE (13S)-HYDROPEROXIDE OR METHYL LINOLEATE

alpha-Tocopherol and methyl (9Z,11 E)-(S)-13-hydroperoxy-9,11 -octadec adienoate (13-MeLOOH) were allowed to stand at 100 degrees C in bulk p hase. The products were isolated and identified as methyl 13-hydroxyoc tadecadienoate (1), stereoisomers of methyl 9,11,13-octadecatrienoate (2), methyl 13-oxo-9,11-octadecadienoate (3), epoxy dimers of methyl l inoleate with an ether bond (4), a mixture of methyl 12,13-epoxy-9-alp ha-tocopheroxy)-10-octadecenoates and methyl 2,13-epoxy-11-(alpha-toco pheroxy)-9-octadecenoates (5), a mixture of methyl 9-(alpha-tocopherox y)-10,12-octadecadienoates and methyl 13-(alpha-tocopheroxy)-9,11-octa decadienoates (6), alpha-tocopherol spirodiene dimer (7), and alpha-to copherol trimer (8). alpha-Tocopherol and 13-MeLOOH were dissolved in methyl myristate, and the thermal decomposition rate and the distribut ions of reaction products formed from alpha-locopherol and 13-MeLOOH w ere analyzed. alpha-Tocopherol disappeared during the first 20 min, an d the main products of alpha-tocopherol were 5 and 6 with the accumula tion of 1-4 which were the products of 13-MeLOOH. The results indicate that the alkyl and alkoxyl radicals from the thermal decomposition of 13-MeLOOH could be trapped by alpha-tocopherol to produce 5 and 6. Th e reaction products of alpha-tocopherol during the thermal oxidation o f methyl linoleate were compounds 6 and 7. Since the radical flux duri ng the autoxidation might be low, the-excess alpha-tocopheroxyl radica l reacted with each other to form 7.