Identification of oxygenated ions in premixed flames of dimethyl ether and oxygen

Abstract

The structure of characteristic flame-ions in premixed flames of dimethyl ether and oxygen was studied by ion–molecule reactions with ammonia and collision activation with argon. The results obtained show that the flame-ions m/z 45 and m/z 47 are the methoxymethyl cation, CH₃OCH₂⁺, and protonated dimethyl ether, (CH₃)₂OH⁺. The flame-ion m/z 61 is a mixture of the trimethyloxonium ion, (CH₃)₃O⁺ and lesser amounts of protonated methyl formate and/or protonated ethyl methyl ether. The viability of an ionic mechanism to soot formation for dimethyl ether–oxygen flames is discussed on the background of ions present in the dimethyl ether flames and the reactivity of the ions.