Kinetic Study of the Reactions of C2H5O and C2H5O2 with NO3 at 298 K

A discharge flow reactor coupled to laser-induced fluorescence and mass spectrometry, for the detection of ethoxy and nitrate radicals, respectively, has been used to study the kinetics of the reactions of C 2 H 5 O and C 2 H 5 O 2 with NO 3 at ca. 1 Torr of helium and 298 K. From the analysis of the C 2 H 5 O concentration−time profiles in two sets of experiments, the reactions C 2 H 5 O + NO 3 → C 2 H 5 O 2 + NO 2 (1) and C 2 H 5 O 2 + NO 3 → C 2 H 5 O + NO 2 + O 2 (2) were observed to be strongly coupled. The rate constants were derived from modeling calculations, k 1 = (3.3 ± 0.9) × 10 -12 cm 3 molecule -1 s -1 and k 2 = (2.3 ± 0.5) × 10 -12 cm 3 molecule -1 s -1 . These data are compared with other very recent literature data, and their atmospheric significance for nighttime chemistry is briefly discussed.