KINETIC-STUDY OF THE REACTIONS OF C2H5O AND C2H5O2 WITH NO3 AT 298 K

A discharge flow reactor coupled to laser-induced fluorescence and mas s spectrometry, for the detection of ethoxy and nitrate radicals, resp ectively, has been used to study the kinetics of the reactions of C2H5 O and C2H5O2 with NO3 at ca. 1 Torr of helium and 298 K. From the anal ysis of the C2H5O concentration-time profiles in two sets of experimen ts, the reactions C2H5O + NO3 --> C2H5O2 + NO2 (1) and C2H5O2 + NO3 -- > C2H5O + NO2 + O-2 (2) were observed to be strongly coupled. The rate constants were derived from modeling calculations, k(1) = (3.3 +/- 0. 9) x 10(-12) cm(3) molecule(-1) s(-1) and k(2) = (2.3 +/- 0.5) x 10(-1 2) cm(3) molecule(-1) s(-1). These data are compared with other very r ecent literature data, and their atmospheric significance for nighttim e chemistry is briefly discussed.