A kinetic study of the gas‐phase reactions of OIO with NO, NO 2 , and Cl 2

The kinetics of iodine dioxide (OIO) reactions with nitric oxide (NO), nitrogen dioxide (NO 2 ), and molecular chlorine (Cl 2 ) are studied in the gas‐phase by cavity ring‐down spectroscopy. The absorption spectrum of OIO is monitored after the laser photodissociation, 266 or 355 nm, of the gaseous mixture, CH 2 I 2 /O 2 /N 2 , which generates OIO through a series of reactions. The second‐order rate constant of the reaction OIO + NO is determined to be (4.8 ± 0.9) × 10 −12 cm 3 molecule −1 s −1 under 30 Torr of N 2 diluent at 298 K. We have also measured upper limits for the second‐order rate constants of OIO with NO 2 and Cl 2 to be k   OIO+NO   2< 6 × 10 −14 cm 3 molecule −1 s −1 and k   OIO+NO   2< 8 × 10 −13 cm 3 molecule −1 s −1 , respectively. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 688–693, 2007