Investigation of the radical product channel of the CH(3)OCH(2)O(2) + HO(2) reaction in the gas phase.

The reaction of CH(3)OCH(2)O(2) with HO(2) has been investigated at 296 K and 700 Torr using long path FTIR spectroscopy, during photolysis of Cl(2)/CH(3)OCH(3)/CH(3)OH/air mixtures. The branching ratio for the reaction channel forming CH(3)OCH(2)O, OH, and O(2) has been determined from experiments in which OH radicals were scavenged by addition of benzene to the system, with subsequent formation of phenol used as the primary diagnostic for OH radical formation. The dependence of the phenol yield on the initial peroxy radical precursor reagent concentration ratio, [CH(3)OH](0)/[CH(3)OCH(3)](0), is consistent with prompt OH formation resulting mainly from the reaction of CH(3)OCH(2)O(2) with HO(2), such that the inferred prompt yield of OH is well-correlated with that of CH(3)OCH(2)OOH, a well-established product of the CH(3)OCH(2)O(2) + HO(2) reaction. The system was fully characterized by simulation, using a detailed chemical mechanism which included other established sources of OH in the system. This allowed a branching ratio of k(2c)/k(2) = 0.19 +/- 0.08 to be determined. The results therefore provide strong indirect evidence for the participation of the radical-forming channel of the title reaction.