Kinetics and Mechanistic Insights into the Ozonolysis of Limona Ketone

Limona ketone, as a significant intermediate in the oxidation of limonene, plays a crucial role in environmental and human health impacts. In this article, we present a study on the reaction kinetics and mechanism of ozonolysis of limona ketone. The rate constant for the reaction between limona ketone and ozone was measured under standard conditions of 298 K and atmospheric pressure by the absolute rate method and was determined to be (1.2 ± 0.1) × 10^-16 cm³ molecule^-1 s^-1. The reaction products were probed online with a vacuum ultraviolet (VUV) photoionization time-of-flight mass spectrometer and utilized to elucidate the reaction mechanism with the aid of kinetics. The atmospheric lifetime of limona ketone was discussed with the present reaction rate constant of limona ketone with O₃, combined with the literature-reported rate constants for OH and NO₃ reaction. The present results show that in urban areas with elevated ozone levels, ozonolysis is the primary pathway for the degradation of limona ketone, and its low-volatility organic products could significantly contribute to the formation of secondary organic aerosols.