Kinetics of Hydrogen Abstraction and Addition Reactions of 3-Hexene by ȮH Radicals

Yang, Fuqiang; Deng, Fuquan; Pan, Youshun; Zhang, Yingjia; Tang, Chenglong; Huang, Zuohua

doi:10.1021/acs.jpca.6b11499

Cited by 25 publications

(16 citation statements)

References 50 publications

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“…As seen in Figure 4, there is excellent agreement between the simulation results and the experimental data (within the uncertainty of the experimental data) for the temperature range 840-1050 K. Below 840 K, the simulations predict negative temperature coefficient (NTC) behavior starts for 2-hexene, which was not observed experimentally. The work by Yang et al 16 for trans-3-hexene predicts NTC behavior below ∼700 K, which is consistent with the experimental results of this study.…”

Section: F I G U R Esupporting

confidence: 92%

“…The "lumped" C 6 H 12 -3 + OH = PC 4 H 9 + CH 3 CHO reaction was removed from the Mehl et al mechanism, and (as described above) analogies were used to estimate new rate coefficients for the C 6 H 12 OH-3 + OH = C 6 H 11 3-1 + H 2 O, C 6 H 12 OH-3 + OH = C 6 H 11 2-4 + H 2 O, and C 6 H 12 OH-3 + OH = C 6 H 12 OH-3 reactions. Note that the rate coefficient recommendations of Yang et al 16 for C 6 H 12 OH-3 + OH do not appear consistent in comparison with similar systems, and consequently were not considered here. The results of the revised mechanism for 3-hexene are presented in Figure 5 as the dashed lines.…”

Section: Discussionmentioning

confidence: 99%

“…The most recent experimental and computational work on the linear hexene isomers is from Yang et al [14][15][16] who studied ignition characteristics of trans-3-hexene behind reflected shock waves at high temperatures and equivalence ratios ranging from 0.5 to 1.5. They found the Mehl et al 2 mechanism failed to capture the pressure dependence at high temperature.…”

Section: Introductionmentioning

confidence: 99%

“…In a companion study, Yang et al 15 studied the ignition behavior of 1‐hexene and trans ‐2‐hexene using reflected shock waves at P = 1.2‐10 atm and T = 1020‐1900 K. They found the trans ‐2‐hexene isomer to be more reactive than 1‐hexene and proposed the difference was due to stabilization of intermediate radicals formed by 1‐hexene. In their computational study, Yang et al 16 used ab initio transition state modeling to evaluate the rates and branching fractions of the trans ‐3‐hexene + OH reactions. The modeling results showed the OH addition to trans ‐3‐hexene was the most important reaction pathway for temperatures <450 K. For temperatures above 1000 K, H‐atom abstraction (with over 70% removal of the allylic H atom) was the dominant reaction path.…”

Section: Introductionmentioning

confidence: 99%

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Effects of stereoisomeric structure and bond location on the ignition and reaction pathways of hexenes

Barraza-Botet

Liu

Kim

et al. 2020

Int J of Chemical Kinetics

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The current work presents new experimental autoignition and speciation data on the two cis-hexene isomers: cis-2-hexene and cis-3-hexene. The new data provide insights on the effects of carbon-carbon double bond location and stereoisomeric structures on ignition delay times and reaction pathways for linear hexene isomers. Experiments were performed using the University of Michigan rapid compression facility to determine ignition delay times from pressure-time histories. Stoichiometric (ϕ = 1.0) mixtures at dilution levels of inert gas to O 2 = 7.5:1 (mole basis) were investigated at an average pressure of 11 atm and temperatures from 809 to 1052 K. Speciation experiments were conducted at T = 900 K for the two cishexene isomers, where fast-gas sampling and gas chromatography were used to identify and quantify the two cis-hexene isomers and stable intermediate species. The ignition delay time data showed negligible sensitivity to the location of the carbon-carbon double bond and the stereoisomeric structure (cis-trans), and the species data showed no correlation with the stereoisomeric structure, but there was a strong correlation of some of the measured species with the location of the double bond in the hexene isomer. In particular, 2-hexene showed strong selectivity to propene, acetaldehyde, and 1,3-butadiene, and 3-hexene showed selectivity to propanal. Model predictions of ignition delay times were in excellent agreement with the experimental data. There was generally good agreement for the model predictions of the species data for 2-hexene; however, the mechanism overpredicted some of the small aldehyde (C 2-C 4) species for 3-hexene. Reaction pathway analysis indicates the hexenes are almost exclusively consumed by Hatom abstraction reactions at the conditions studied (P = 11 atm, T > 900 K), and not by C 3-C 4 scission as observed in high-temperature (>1300 K) hexene ignition studies. Improved estimates for 3-hexene + OH reactions may improve model predictions for the species measured in this work.

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Section: F I G U R Esupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effects of stereoisomeric structure and bond location on the ignition and reaction pathways of hexenes

Barraza-Botet

Liu

Kim

et al. 2020

Int J of Chemical Kinetics

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show abstract

“…They also calculated the rate coefficient to be 8.10 × 10 –11 cm 3 molecule –1 s –1 via the microcanonical variational transition state method based on BHandHLYP/aug-cc-pVDZ quantum chemical calculations. An exceptionally low rate coefficient (0.05 × 10 –11 cm 3 molecule –1 s –1 ) was predicted for trans -3-hexene + OH by Yang et al, two orders of magnitude smaller than that obtained for our system and other similar systems listed in Table . It is notable that the barrier height for the addition of OH to 3-hexene was computed as −0.21 kcal/mol at the CCSD(T)/CBS//BHandHLYP/6-311G(d,p) level, significantly higher than our calculated OH-addition barrier (−2.3 kcal/mol) for 3-MH in this work; thus, the overestimation of the energy barrier in Yang’s work likely results in the discrepancy of the total rate coefficient.…”

contrasting

confidence: 74%

Formation of Substituted Alkyls as Precursors of Peroxy Radicals with a Rapid H-Shift in the Atmosphere

Huang

Chai

et al. 2021

J. Phys. Chem. Lett.

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Long straight-chain alkyl peroxy (ROO) radicals substituted with CC and oxo functional groups are expected to undergo a rapid hydrogen shift (H-shift), which is a critical step in the atmospheric autoxidation mechanism. The existence of a weak tertiary C−H bond plays a key role in the rapid H-shift. Here, the reaction kinetics between OH and two typical long straight-chain functionalized volatile organic compounds, 3-methyl-1-hexene (3-MH) and 2-methylpentanal (2-MP), was theoretically investigated to reveal the fate of the weak C−H bond. The results indicate that the most favored reaction pathways are direct consumption (H-abstraction of 2-MP) and indirect destruction (addition of OH to 3-MH) of the "weak" tertiary C−H bond. The yields of abstraction pathways producing precursors of ROO radicals that undergo rapid H-shifts are computed to be less than 10% for both 3-MH + OH and 2-MP + OH reactions.

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Automatic mechanism generation for the combustion of advanced biofuels: A case study for diethyl ether

Michelbach,

Tomlin

2023

Int J of Chemical Kinetics

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Advanced biofuels have the potential to supplant significant fractions of conventional liquid fossil fuels. However, the range of potential compounds could be wide depending on selected feedstocks and production processes. Not enough is known about the engine relevant behavior of many of these fuels, particularly when used within complex blends. Simulation tools may help to explore the combustion behavior of such blends but rely on robust chemical mechanisms providing accurate predictions of performance targets over large regions of thermochemical space. Tools such as automatic mechanism generation (AMG) may facilitate the generation of suitable mechanisms. Such tools have been commonly applied for the generation of mechanisms describing the oxidation of non‐oxygenated, non‐aromatic hydrocarbons, but the emergence of biofuels adds new challenges due to the presence of functional groups containing oxygen. This study investigates the capabilities of the AMG tool Reaction Mechanism Generator for such a task, using diethyl ether (DEE) as a case study. A methodology for the generation of advanced biofuel mechanisms is proposed and the resultant mechanism is evaluated against literature sourced experimental measurements for ignition delay times, jet‐stirred reactor species concentrations, and flame speeds, over conditions covering φ = 0.5–2.0, P = 1–100 bar, and T = 298–1850 K. The results suggest that AMG tools are capable of rapidly producing accurate models for advanced biofuel components, although considerable upfront input was required. High‐quality fuel specific reaction rates and thermochemistry for oxygenated species were required, as well as a seed mechanism, a thermochemistry library, and an expansion of the reaction family database to include training data for oxygenated compounds. The final DEE mechanism contains 146 species and 4392 reactions and in general, provides more accurate or comparable predictions when compared to literature sourced mechanisms across the investigated target data. The generation of combustion mechanisms for other potential advanced biofuel components could easily capitalize on these database updates reducing the need for future user interventions.

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Kinetics of Hydrogen Abstraction and Addition Reactions of 3-Hexene by ȮH Radicals

Cited by 25 publications

References 50 publications

Effects of stereoisomeric structure and bond location on the ignition and reaction pathways of hexenes

Effects of stereoisomeric structure and bond location on the ignition and reaction pathways of hexenes

Formation of Substituted Alkyls as Precursors of Peroxy Radicals with a Rapid H-Shift in the Atmosphere

Automatic mechanism generation for the combustion of advanced biofuels: A case study for diethyl ether

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