61508-72-3Relevant academic research and scientific papers
Kinetics of sulfur oxide, sulfur fluoride, and sulfur oxyfluoride anions with atomic species at 298 and 500 K
Midey, Anthony J.,Viggian
, p. 1852 - 1859 (2007)
The rate constants and product-ion branching ratios for the reactions of sulfur dioxide (SO2-), sulfur fluoride (SF n-), and sulfur oxyfluoride anions (SOxF y-) with H, H2, N, N2, NO, and O have been measured in a selected-ion flow tube (SIFT). H atoms were generated through a microwave discharge on a H2/He mixture, whereas O atoms were created via N atoms titrated with NO, where the N had been created by a microwave discharge on N2. None of the ions reacted with H 2, N2 or NO; thus, the rate constants are -12 cm3 s-1. SOxFy - ions react with H by only fluorine-atom abstraction to form HF at 298 and 500 K. Successive F-atom removal does not occur at either temperature, and the rate constants show no temperature dependence over this limited range. SO2- and F- undergo associative detachment with H to form a neutral molecule and an electron. Theoretical calculations of the structures and energetics of HSO2- isomers were performed and showed that structural differences between the ionic and neutral HSO 2 species can account for at least part of the reactivity limitations in the SO2- + H reaction. All of the SOxF y- ions react with O; however, only SO2 - reacts with both N and O. SOxFy- reactions with N (SO2- excluded) have a rate constant limit of -11 cm3 s-1. The rate constants for the SOxFy- reactions with H and O are ≤25% of the collision rate constant, as seen previously in the reactions of these ions with O3, consistent with a kinetic bottleneck limiting the reactivity. The only exceptions are the reactions of SO2 - with N and O, which are much more efficient. Three pathways were observed with O atoms: F-atom exchange in the reactant ion, F- exchange in the reactant ion, and charge transfer to the O atom. No associative detachment was observed in the N- and O-atom reactions.
