Experimental and kinetic modeling study of the low- and intermediate-temperature oxidation of dimethyl ether

Quantification of the Keto-Hydroperoxide (HOOCH2OCHO) and Other Elusive Intermediates during Low-Temperature Oxidation of Dimethyl Ether

“…This section of the paper also includes a discussion of the limitations of our approach to determine PICS with respect to the separation and quantification of isomeric species. Figure 3 has revealed that all three DME mechanisms (USTC, 19 NUI, 18 and Nancy 5 ) considered here differ already significantly in their predictions for the main species profiles. In the following discussion only a few comparisons between the mechanisms' different description of the detailed chemistry are provided and instead we refer the reader to the papers, in which the mechanisms have been described, for the origins of the different predictions.…”

“…In the following discussion only a few comparisons between the mechanisms' different description of the detailed chemistry are provided and instead we refer the reader to the papers, in which the mechanisms have been described, for the origins of the different predictions. 5,18,19 In order to suggest targeted refinements to the mechanisms, it is crucial to further constrain them with reliable quantitative intermediate species profiles. As mentioned earlier, the lowtemperature oxidation of DME involves many partially oxidized and elusive intermediate species.…”

“…In order to validate the low-temperature part of the DME combustion chemistry mechanisms 5,18,19 and to identify opportunities for improvements, the quantification of the combustion reactants, intermediates, and products is crucial. The experimental mole fraction profiles of the main species (H 2 O, CO, O 2 , Ar, CO 2 , and DME) as a function of the reactor temperature were shown in Figure 3 and discussed together with the model predictions in the experimental section 2.2 as part of the data evaluation procedures.…”

“…As pointed out by Wang et al, 19 this peak results from a large reaction rate of the OH addition to CH 2 O forming HOCH 2 O, which serves as precursor for CH 2 O 2 .…”

“…In order to give a more complete data set, a total of 15 reactants, products, and intermediates (including key intermediates like H 2 O 2 , HCOOH, and CH 3 OCHO) were also quantified. The new mole fraction profiles are then compared to model predictions using the most widely validated and accepted detailed chemical kinetic mechanisms for DME oxidation, 5,18,19 to illustrate their capabilities and possibilities for an improved description of DME's low-temperature chemistry.…”