Aldehyde Formation in the Reaction of Methoxy Radicals with NO3

Abstract

The reaction of methoxy radicals with NO 3 has been studied using a discharge flow system coupled to LIF and MS detectors. From a detailed analysis of reactants and products the reaction was identified to procede predominantly via channels (1a) and (1b). CH 3 O+NO 3 → CH 3 O 2 +NO 2 (1a) →CH 2 O+HNO 3 (1b) Employing CD 4 for methoxy radical generation the branching ratios k 1a /k 1 = (0.49±0.1) and k 1b /k 1 = (0.44±0.1) have been determined. Thus aldehyde is a major primary product of reaction (1). The overall rate constants for reactions (1) and (2) were found to be CH 3 O 2 +NO 3 →CH 3 O+NO 2 +O 2 (2) k 1 =(3.44±0.5).10 -12 and k 2 =(3.1±0.5).10 -12 , in units cm 3 .molecule -1 .s -1 , in acceptable agreement with previous investigations.