Investigation of Chlorine-initiated Oxidation Reactions of Nopinone by Vacuum Ultraviolet Photoionization Mass Spectrometry

A microwave discharge fast flow tube reactor was used to simulate chlorine- initiated oxidation of nopinone(C9H14O). The chemical compositions of radicals and stable products from the oxidation reactions were measured via a home-made vacuum ultraviolet photoionization time of flight mass spectrometer(VUVPI-TOFMS). The kinetic experiments of main radicals and products were also performed. By comparing the results of kinetic experiments and simulation calculations of key species, the reaction pathways of key species in the reaction were further explored. This study showed that the reaction of nopinone with Cl produced radical C9H13O via the hydrogen abstraction pathway. The radical C9H13O reacted with O-2 to mainly generate peroxy radical C9H13OO2. Under NOx(NO and NO2)free condition, peroxy radical C9H13OO2 reacted with itself to produce radical C9H13OO, carbonyl compounds C9H13OO2 and C9H13OOH. In addition, the peroxy radical C9H13OO2 could also react with HO2 to produce hydroperoxide C9H13OO2H. The mechanism of chlorine-initiated oxidation reactions of nopinone was also revealed through experimental studies and simulation calcu lations.