Experimental and computational kinetic investigations for the reactions of Cl atoms with unsaturated ketones in the gas phase. (31st October 2017) - Vijayakumar, S.
Abstract : Cl atom initiated photo oxidation of unsaturated ketones. Abstract : Temperature dependent rate coefficients for the gas phase reactions of Cl atoms with 4-hexen-3-one and 5-hexen-2-one were measured as a function of temperature (298–363 K) and pressure (500–760 Torr; N2 and O2 ) relative to 1, 3-butadiene, isoprene and 1-pentene. Gas Chromatography (GC) coupled with a Flame Ionization Detector (FID) was used to measure the concentrations of the organics. The derived temperature dependent Arrhenius expressions are k 1 = (2.82 ± 1.76) × 10 −12 exp [(1556 ± 438)/ T ] cm 3 molecule −1 s −1 and k 2 = (4.6 ± 2.4) × 10 −11 exp [(646 ± 171)/ T ] cm 3 molecule −1 s −1 . The corresponding room temperature rate coefficients are (5.55 ± 1.31) × 10 −10 cm 3 molecule −1 s −1 and (4.14 ± 1.25) × 10 −10 cm 3 molecule −1 s −1 for the reactions of Cl atoms with 4-hexen-3-one and 5-hexen-2-one respectively. To complement our experimental results, computational calculations were performed for the reactions of Cl atoms with 4-hexen-3-one, 5-hexen-2-one and 3-penten-2-one over the temperature range of 275–400 K using Canonical Variational Transition state theory (CVT) with Small Curvature Tunneling (SCT) in combination with the CCSD(T)/6-31+G(d, p)//MP2/6-311++G(d, p) level of theory. Atmospheric implications, reaction mechanism and feasibility of the title reactions are discussed in this manuscript.