P. Dagaut et al., The low temperature oxidation of DME and mutual sensitization of the oxidation of DME and nitric oxide: Experimental and detailed kinetic modeling, COMB SCI T, 165, 2001, pp. 61-84
The oxidation of dimethylether (DME) has been studied experimentally at low
-temperature (550-800 K) in a jet-stirred reactor operating at I atm. The m
utual sensitization of the oxidation of dimethylether and NO was also studi
ed. It was shown that above 600 K, NO enhances the oxidation of DME in the
cool flame regime and yields methylformate (not formed without NO) whereas
NO is oxidized to NO2. Below 600 K, the oxidation of DME was inhibited by N
O. A detailed chemical kinetic model was developed to simulate the present
experiments and the ignition of DME/air mixtures in shock tube at 13 and 40
atm. A good agreement between the experimental results and the modeling wa
s generally obtained. According to the proposed kinetic mechanism, in the p
resent conditions, the mutual sensitization of the oxidation of DME and NO
proceeds through the following sequence: DME + OH --> CH3OCH2(R); R + O-2--
> RO2; RO2 + NO --> RO + NO2; RO --> methylformate + H; RO + O-2 --> methyl
formate + HO2; HO2 + NO --> OH + NO2. The inhibition of DME oxidation below
600 K is due to RO2 + NO --> RO + NO2 that reduces the production of OH by
competition with the isomerization RO2 --> QO(2)H responsible for chain-br
anching: QO(2)H + O-2 --> O(2)QO(2)H HO(2)Q'O + OH; QO(2)H --> 2CH(2)O + OH
; HO(2)Q'O --> OQ'O + OH.