High-temperature oxidation chemistry of n-butanol – experiments in low-pressure premixed flames and detailed kinetic modeling

Abstract

An automated reaction mechanism generator is used to develop a predictive, comprehensive reaction mechanism for the high-temperature oxidation chemistry of n-butanol. This new kinetic model is an advancement of an earlier model, which had been extensively tested against earlier experimental data (Harper et al., Combust. Flame, 2011, 158, 16-41). In this study, the model's predictive capabilities are improved by targeting isomer-resolved quantitative mole fraction profiles of flame species in low-pressure flames. To this end, a total of three burner-stabilized premixed flames are isomer-selectively analyzed by flame-sampling molecular-beam time-of-flight mass spectrometry using photoionization by tunable vacuum-ultraviolet synchrotron radiation. For most species, the newly developed chemical kinetic model is capable of accurately reproducing the experimental trends in these flames. The results clearly indicate that n-butanol is mainly consumed by H-atom abstraction with H, O, and OH, forming predominantly the α-C(4)H(9)O radical (CH(3)CH(2)CH(2)˙CHOH). Fission of C-C bonds in n-butanol is only predicted to be significant in a similar, but hotter flame studied by Oßwald et al. (Combust. Flame, 2011, 158, 2-15). The water-elimination reaction to 1-butene is found to be of no importance under the premixed conditions studied here. The initially formed isomeric C(4)H(9)O radicals are predicted to further oxidize by reacting with H and O(2) or to decompose to smaller fragments via β-scission. Enols are detected experimentally, with their importance being overpredicted by the model.

Resistance switching of epitaxial VO2/Al2O3 heterostructure at room temperature induced by organic liquids

“…37,39 Because of the weaker reducibility of n-butanol than cyclohexane, [40][41][42][43] n-butanol modulates the resistance less than cyclohexane does.…”

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

“…However, in the experiment only a weak CH 3 signal was detected, maybe indicating that CH 3 is not as well detected as in many high-temperature flame studies. [83][84][85] It is possible that in the current low-temperature experiments CH 3 is mostly captured in the form of CH 3 O 2 whereas in the high-temperature flames the CH 3 + O 2 ⇄ CH 3 O 2 equilibrium strongly favors dissociation back to the reactants.…”

Comparative Autoignition Trends in Butanol Isomers at Elevated Pressure

“…In addition to applied engine research, [6][7][8] fundamental combustion measurements have been made using many different systems. These include laminar flame speeds, 9 flame stability measurements, 10 jet-stirred reactor chemistry, 11 low-pressure flame structure, 12 atmospheric pressure flame structure, 13 pyrolysis, 14 flow reactors, 15 and ignition delays, both in rapid compression machines (RCMs) and shock tubes. 16,17 There have also been numerous modeling studies of the isomers of butanol, including recent ones by Sarathy et al, 18 Hansen et al, 19 and…”