Oxygen Insertion Mechanism of the Singlet Oxygen Atom Reaction with Dimethyl Ether*

In situ laser spectroscopy, quantum chemistry, and kinetic calculations are integrated to study the reaction of photolytically generated singlet oxygen atoms with dimethyl ether in a well-characterized flow reactor. This is an initiation and branching reaction which is important in the gas-phase plasma chemistry.  Infrared laser absorption spectroscopy and Faraday rotation spectroscopy are used for the detection and quantification of the reaction products. Fitting temporal profiles of products with simulations allows product branching to be quantified and the major channel yields two CH3O radicals. The experimentally determined product branching agrees well with master equation calculations,which show that a weakly bound charge transfer complex (CH3OOCH3) is formed by O insertion into the C-O bond. This O insertion mechanism can be important for understanding the plasma-based biofuel processing technologies.