Hydroxyl Radical Induced Oxidation of Diethyl Ether in Oxygenated Aqueous Solution. A Product and Pulse Radiolysis Study

Article abstract of DOI:10.1021/j100208a017

The reaction of peroxyl radicals derived from diethyl ether were investigated by product analyses and pulse-radiolytic techniques.The products and their G values in the γ radiolysis of diethyl ether (1E-3 M) in N2O/O2-saturated aqeous solutions at 0.43 W kg^-1 are acetaldehyde <0.6>, ethanol <0.6>, ethyl acetate <2.8>, ethyl formate <0.7>, formaldehyde <0.4>, hydrogen peroxide <2.1>, 1-ethoxyethyl hydroperoxide <1.2>, and 2-ethoxyacetaldehyde .Except for the latter, all products have the 1-ethoxyethylperoxy radical (I) as a precursor.It is formed as the major radical by OH abstraction of the α-H atom (96percent) followed by O2 addition.Besides other bimolecular decay processes of I which are also discussed, there is an important route leading to 1-ethoxyethyloxyl radicals and O2: 2I -> 2CH3CH(O*)OEt + O2.The oxyl radical rearrangment in aqueous solutions to the 1-ethoxy-1-hydroxyethyl radical: CH3CH(O*)OEt -> CH3C*(OH)OEt.The latter adds oxygen to give the corresponding peroxyl radical, which eliminates HO2* in a fast spontaneous reaction to give ethyl acetate: CH3C*(OH)OEt + O2 - HO2* -> CH3COOEt.Evidence for the formation of HO2* (O2^-* in neutral and basic solutions) according to the above reaction sequence was provided by pulse-spectrometric and pulse-conductometric measurements. 1-Ethoxyethyl hydroperoxide is thought to result from the reduction of I by O2^-*.At much lower dose rates (0.0048 W kg^-1) an intramolecular H abstraction competes with the bimolecular decay of I.This process leads to a different product distribution and to formation of acidic products.