1188
J . Phys. Chem. 1988, 92, 1188-1 193
Laboratory Studies of NO, Radlcal Reactions wlth Some Atmospheric Sulfur Compounds Edward J. Dlugokencky and Carleton J. Howard* Aeronomy Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80303, and Cooperative Institute for Research in Environmental Sciences and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado (Received: June 22, 1987; In Final Form: September 28, 1987)
The reactions of nitrate radicals (NO,) with CH3SCH3(DMS), CH3SH, CH3SSCH3(DMDS), H2S, and SO2have been studied at low pressures in a fast flow reactor with LIF detection of NO,. All experiments were performed under pseudo-first-order conditions in NO3, using thermolysis of N20Sas a source of NO,. The reaction of NO, with DMS (1) was studied between 0.46 and 4.5 Torr and as a function of temperature from 256 to 376 K. The rate coefficient for the reaction is ki(T) = (1.79 & 0.22) X exp[530 k 40/T] cm3 molecule-' s-' with no dependence on pressure. All error limits are the 95% confidence levels and include a factor for systematic errors. The reaction of NO3 with CH3SH (2) was studied (3111, molecule-' over the temperature range 254-367 K, and the rate constant was found to be k2(7') = (1.09 f 0.17) X s-' independent of temperature and pressure in the range 0.45-4.5 Torr. For both of these reactions, we determined that NO2 was not a significant product,
