Effects of Metal Ions and pH on the Stability of Linoleic Acid Hydroperoxide in the Water Phase.

We examined linoleic acid hydroperoxide (hydroperoxyoctadecadienoic acid; HPOD) decomposition kinetically with or without various metal ions and at various pHs as effective factors on the stability of hydroperoxides. HPOD decomposition in the reaction system of this experiment was a first-order reaction. Manganese, copper, and especially iron accelerated the decomposition of HPOD, while lithium, sodium, potassium, magnesium, calcium, and aluminium stabilized HPOD. Besides, HPOD was comparatively stable at pH 3, 7, and 8, and unstable at pH 2, 4-6, and 9. According to activation energy, however, it was estimated that only in the reaction system with iron or at pH 2 and 9 the HPOD decomposition mechanism was different from that in water.