EFFECTS OF UV IRRADIATION AND PHOTOCATALY SIS OF TIO2 ON AUTOXIDATIONRATE OF LINOLEIC-ACID

Autoxidation of linoleic acid was carried out in the temperature range from 323 K to 343 K using a bubble column reactor. A slow initial inc rease in hydroperoxide at low concentration range of hydroperoxide (in duction period) and a rapid increases in hydroperoxide at high concent ration of hydroperoxide after a certain time (acceleration period) wer e observed during the reaction. The experimental results are analyzed by the radical chain reaction model proposed. The rate equation of hyd roperoxide formation with two apparent kinetic constants is developed to explain the autoxidation rate of linoleic acid. Effects of UV irrad iation in the presence or absence of TiO2 powder are also studied. Aut oxidation of linoleic acid was accelerated by UV irradiation and espec ially by the photocatalytic effect of TiO2. A remarkable acceleration effect by UV and photocatalysis of TiO2 is observed in the induction p eriod and these effects are enhanced at lower temperature.