Low-Temperature Combustion Chemistry of <i>n-</i>Butanol: Principal Oxidation Pathways of Hydroxybutyl Radicals

Welz, Oliver; Zádor, Judit; Savee, John David; Sheps, Leonid; Osborn, David L.; Taatjes, Craig A.

doi:10.1021/jp403792t

Cited by 43 publications

(40 citation statements)

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“…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.…”

Section: Resultsmentioning

confidence: 99%

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

et al. 2015

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We studied using organic liquids (cyclohexane, n-butanol, and ethylene glycol) to modulate the transport properties at room temperature of an epitaxial VO2 film on a VO2/Al2O3 heterostructure. The resistance of the VO2 film increased when coated with cyclohexane or n-butanol, with maximum changes of 31% and 3.8%, respectively. In contrast, it decreased when coated with ethylene glycol, with a maximum change of −7.7%. In all cases, the resistance recovered to its original value after removing the organic liquid. This organic-liquid-induced reversible resistance switching suggests that VO2 films can be used as organic molecular sensors.

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“…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.…”

Section: Resultsmentioning

confidence: 99%

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

et al. 2015

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“…Whereas the dominance of HO 2 elimination from α-RO 2 is a similarity in the oxidation of saturated and unsaturated alcohols, the reactivity of the β, γ, and -RO 2 is greatly altered. For instance, in the lowtemperature oxidation of n-butanol [4] and isopentanol [2,8] the most favored reaction of γ-RO 2 is Hatom abstraction from the carbon atom connected to the alcoholic -OH group, forming the QOOH radical γ-Q 1 . The γ-RO 2 ↔ γ-Q 1 isomerization barrier in these systems is over 70 kJ mol -1 below the γ-R + O 2 energy.…”

Section: Resultsmentioning

confidence: 99%

“…The reactants (either prenol or isoprenol), Cl 2 , and O 2 , all diluted in helium, are as outlined in Refs. [2,4]. In the present work, product yields, defined as [product] formed / [unsaturated alcohol] consumed , are derived by comparing the photoionization signals for the depletion of prenol/isoprenol with those for product formation.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…Many different types of biofuels are under consideration, amongst them short-and mediumchain saturated alcohols, particularly ethanol, a currently widely used biofuel, the butanol isomers and isopentanol. Fundamental studies on their low-temperature oxidation chemistry [2][3][4][5] have revealed a rich QOOH chemistry and have shown that the alcoholic -OH group significantly alters reactivity when compared to alkane oxidation and introduces new pathways, such as the Waddington mechanism [6,7] or water elimination. [8] Detailed chemical kinetics combustion mechanisms have been developed, which include alcohol-specific low-temperature chemistry and which can successfully model global combustion targets, such as ignition delay time measurements.…”

Section: Introductionmentioning

confidence: 99%

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Chlorine atom-initiated low-temperature oxidation of prenol and isoprenol: The effect of C C double bonds on the peroxy radical chemistry in alcohol oxidation

Welz

Savee

Osborn

et al. 2015

Proceedings of the Combustion Institute

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The chlorine atom-initiated oxidation of two unsaturated primary C5 alcohols, prenol (3-methyl-2buten-1-ol, (CH 3) 2 CCHCH 2 OH) and isoprenol (3-methyl-3-buten-1-ol, CH 2 C(CH 3)CH 2 CH 2 OH), is studied at 550 K and low pressure (8 Torr). The time-and isomer-resolved formation of products is probed with multiplexed photoionization mass spectrometry (MPIMS) using tunable vacuum ultraviolet ionizing synchrotron radiation. The peroxy radical chemistry of the unsaturated alcohols appears much less rich than that of saturated C4 and C5 alcohols. The main products observed are the corresponding unsaturated aldehydesprenal (3-methyl-2-butenal) from prenol oxidation and isoprenal (3-methyl-3butenal) from isoprenol oxidation. No significant products arising from QOOH chemistry are observed. These results can be qualitatively explained by the formation of resonance stabilized allylic radicals via H-abstraction in the Cl + prenol and Cl + isoprenol initiation reactions. The loss of resonance stabilization upon O 2 addition causes the energies of the intermediate wells, saddle points, and products to increase relative to the energy of the initial radicals and O 2. These energetic shifts make most product channels observed in the peroxy radical chemistry of saturated alcohols inaccessible for these unsaturated alcohols. The experimental findings are underpinned by quantum-chemical calculations for stationary points on the potential energy surfaces for the reactions of the initial radicals with O 2. Under our conditions, the dominant channels in prenol and isoprenol oxidation are the chain-terminating HO 2forming channels arising from radicals, in which the unpaired electron and the OH group are on the same carbon atom, with stable prenal and isoprenal co-products, respectively. These findings suggest that the presence of C=C double bonds in alcohols will reduce low-temperature reactivity during autoignition.

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“…the rate coefficients of hydrogen abstraction reactions, the main consumption channels of fuels in combustion and pyrolysis. In alcohols, hydrogen abstraction reactions from the α-carbon are favored and the resulting radicals react at oxidizing conditions mainly with molecular oxygen forming an aldehyde and a hydroperoxy radical [14][15][16], which is rather unreactive at low temperature.…”

Section: Introductionmentioning

confidence: 99%

Understanding the reactivity of unsaturated alcohols: Experimental and kinetic modeling study of the pyrolysis and oxidation of 3-methyl-2-butenol and 3-methyl-3-butenol

Bruycker

Herbinet

Carstensen

et al. 2016

Combustion and Flame

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. Understanding the reactivity of unsaturated alcohols: Experimental and kinetic modeling study of the pyrolysis and oxidation of 3-methyl-2-butenol and 3-methyl-3-butenol. Combustion and Flame, Elsevier, 2016, 171, pp.237-251. 1 Understanding the reactivity of unsaturated alcohols: Experimental and kinetic modeling study of the pyrolysis and oxidation of 3-methyl-2-butenol and 3-methyl-3-butenol AbstractThe reactivity of unsaturated alcohols with a C=C double bond in the β-and γ-positions to the hydroxyl group is not well established. The pyrolysis and oxidation of two such unsaturated alcohols have been studied, i.e. 3-methyl-2-butenol (prenol) and 3-methyl-3-butenol (isoprenol). Experiments at three equivalence ratios, i.e. φ = 0.5, φ = 1.0 and φ = ∞ (pyrolysis), were performed using an isothermal jet-stirred quartz reactor at temperatures ranging from 500 to 1100 K, a pressure of 0.107 MPa and a residence time of 2 s. The reactant and product concentrations were quantified using gas chromatography. A kinetic model has been developed using the automatic network generation tool "Genesys". Several important rate coefficients are obtained from new quantum chemical calculations. Overall, there is a good agreement between model calculated mole fraction profiles and experimental data. Reaction path analysis reveals that isoprenol consumption is dominated by a unimolecular reaction to formaldehyde and isobutene. At the applied operating conditions, the equivalence ratio has no effect on the isoprenol conversion profile. Pyrolysis and oxidation of prenol is dominated by radical chemistry, with hydrogen abstractions from prenol forming resonantly stabilized radicals as dominating conversion path. Oxidation and decomposition of the resulting radicals are predicted to form 3-methyl-2-butenal and 2-methyl-1,3-butadiene, which have been detected as important products in the reactor effluent.

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Low-Temperature Combustion Chemistry of n-Butanol: Principal Oxidation Pathways of Hydroxybutyl Radicals

Cited by 43 publications

References 90 publications

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

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

Chlorine atom-initiated low-temperature oxidation of prenol and isoprenol: The effect of C C double bonds on the peroxy radical chemistry in alcohol oxidation

Understanding the reactivity of unsaturated alcohols: Experimental and kinetic modeling study of the pyrolysis and oxidation of 3-methyl-2-butenol and 3-methyl-3-butenol

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