Reaction of F Atoms with Carbonyl Sulfide: Experimental and Theoretical Study

The gas phase reaction of fluorine atoms with carbonyl sulfide, F + OCS → SF + CO (1), has been investigated over a wide temperature range, T = 220-960 K, in a discharge-flow system combined with mass spectrometry for the analysis of the reactive mixture. The reaction rate coefficient was determined as a function of temperature using both absolute (under pseudo-first-order conditions using an excess of F atoms) and relative rate methods: k₁ = (8.95 ± 0.52) × 10^-11 exp((102 ± 20)/T) cm³ molecule^-1 s^-1 (with an estimated total uncertainty of 15% independent of temperature). The SF radical was observed as the main primary reaction product. The experimental results are supported by theoretical calculations, which evidence that the reaction is exothermic with a weak negative temperature dependence.