Temperature dependent kinetic study of the gas phase reaction of ozone with 1-penten-3-ol, cis-2-penten-1-ol and trans-3-hexen-1-ol: Experimental and theoretical data. (15th February 2020) - Kalalian, C.
Abstract: C5 and C6 unsaturated alcohols are a family of biogenic volatile organic compounds (BVOC) emitted in the atmosphere from vegetation in response to their injuries. In this work, we report the first temperature dependent rate constants for the reaction of three unsaturated alcohols: 1-penten-3-ol (1P3OL), cis-2-penten-1-ol (c-2P1OL) and tran-3-hexen-1-ol (t-3H1OL) with ozone in a pyrex reactor coupled to a FTIR spectrometer and to a GC/MS at four different temperatures (273, 298, 313 and 333 K), at atmospheric pressure, using a relative method. The Arrhenius expressions obtained are (cm 3 molecule −1 s −1 ): The studied reactions were also explored theoretically using computational methods based on quantum chemical theory characterizing the intermediates, transition states and the subsequent formation of reaction products. The rate constants were calculated at room temperature employing a modified transition-state theory (MTST). Both results obtained experimentally and theoretically, were discussed in terms of structure-reactivity relationships and temperature dependence. Tropospheric lifetimes of the investigated species with respect to ozone are calculated. The obtained results showed that these species are not persistent towards ozonolysis process. Graphical abstract: Image 1 Highlights: Room temperature ozonolysis rate constants of 1P3OL, c-2P1OL and t-3H1OLare 1.68, 10.50 and 6.24 × 10 −17 cm 3 molecule −1 s −1, respectively. The ozonolysis of the studied unsaturated alcohols shows a low positive temperature dependence. Calculations have highlighted the formation of a pre-reaction complex that leads to an activated complex. Atmospheric lifetimes of the studied compounds toward ozone are of few hours.