A detailed chemical mechanism for low to high temperature oxidation of n-butylcyclohexane and its validation

Mao, Yebing; Li, Ang; Zhu, Lei; Wu, Zhiyong; Yu, Liang; Wang, Sixu; Raza, Mohsin; Lü, Xingcai

doi:10.1016/j.combustflame.2019.09.007

Cited by 24 publications

(16 citation statements)

References 75 publications

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“…In previous experimental work on nBCH, Mao et al 7 investigated the ignition behavior of nBCH in a shock tube (ST) and in a rapid compression machine (RCM) over a wide range of temperature, pressure, and equivalence ratio. In a subsequent paper, Mao et al 8 made additional RCM measurements at highly diluted conditions at 10, 15, and 20 bar. They also made species concentration measurements in a flow reactor at 1 atm in the temperature range 650 to 1075 K, and at equivalence ratios of 1 and 1.5.…”

Section: Introductionmentioning

confidence: 99%

“…Mao et al 7 tuned the Natelson et al 9 model with some modification to simulate their combined ST and RCM ignition data. In a subsequent paper, Mao et al 8 proposed a detailed chemical kinetic model for the low‐ and high‐temperature oxidation of nBCH. The chemical kinetic model was validated using experimental data from STs, an RCM, a jet stirred reactor, and a flow reactor and the comparisons showed good agreement.…”

Section: Introductionmentioning

confidence: 99%

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A detailed chemical kinetic modeling and experimental investigation of the low‐ and high‐temperature chemistry of n‐butylcyclohexane

Pitz

Liang

Kukkadapu

et al. 2020

Int J of Chemical Kinetics

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Chemical kinetic models of gasoline, jet, and diesel fuels and their mixtures with bioderived fuels are needed to assess fuel property effects on efficiency, emissions, and other performance metrics in internal combustion and gas turbine engines. As these real fuels have too many fuel components to be included in a chemical kinetic model, surrogate fuels containing fewer components are used to represent them. These surrogate fuels mimic the chemical classes or molecular structures contained in the real fuel. One of the important chemical classes in gasoline, jet, and diesel fuels comprises cyclohexanes. Cyclohexanes comprise about 30% or more by weight in diesel fuel. Also, Mueller et al (Energy Fuels. 2012;26(6):3284‐3303) proposed n‐butylcyclohexane (nBCH) as a component in a nine‐component surrogate palette to represent the ignition properties, distillation curve, density, and molecular structures of a diesel certification fuel. In this work, experimental measurements of the ignition delay times (IDTs) of nBCH in a shock tube and in a rapid compression machine are reported over a wide range of temperature, pressure, and equivalence ratio important for enabling the validation of a chemical kinetic model for nBCH for combustion in diesel engines. The range of conditions are temperatures of 630–1420 K, pressures of 10, 30, and 50 bar, and equivalence ratios of 0.3, 0.5, 1.0, and 2.0 in ‘air’. A detailed chemical model is developed for nBCH to simulate its ignition at both low and high‐temperature conditions and at relevant elevated pressures. The experimentally measured IDTs are used to improve and validate the chemical kinetic model.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A detailed chemical kinetic modeling and experimental investigation of the low‐ and high‐temperature chemistry of n‐butylcyclohexane

Pitz

Liang

Kukkadapu

et al. 2020

Int J of Chemical Kinetics

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“…Very recently, Mao et al have proposed a detailed kinetic model consisting of 1802 species and 7246 reactions to describe the chemistry of n -butyl cyclohexane from a low temperature to a high temperature, and the autoginition and oxidation of n -butyl cyclohexane were investigated over a wide range of conditions. In this kinetic model, the rate constants of the cyclization class were prescribed as the analogous reactions of the cyclohexane, methyl cyclohexane, and alkane models were taken from the previous literature, ,,− and some representative reactions were selected for comparison with our calculated high-pressure-limit rate constants of the corresponding same reactions in this work.…”

Section: Resultsmentioning

confidence: 99%

“…However, the reactions in the class of cyclization are not included in JetSurF 2.0, which are also important for low-temperature combustion modeling of normal-alkyl cyclohexanes. Recently, the low-temperature ethyl cyclohexane and n -butyl cyclohexane oxidation models, incorporating the high- and low-temperature oxidation reaction classes, were constructed by Zou et al and Mao et al In their kinetic models, due to the lack of accurate rate constants for the class of cyclization reactions, the rate constants were prescribed as the analogous reactions of the cyclohexanes, smaller normal-alkyl cyclohexanes, or alkanes were taken from different kinds of literature studies. ,,− However, in our previous study, we chose typical alkylated cyclohexyl peroxy radicals to conduct rate rules, and H-migration reaction classes on alkyl side chains from cycle to chain, from chain to cycle, and on the cycle were studied. In comparison with rate rules of chain alkyl radicals by Villano et al, indicating that the rate rules were not suitable for normal-alkyl cycloalkanes, even the rate constants were prescribed with some necessary modification.…”

Section: Introductionmentioning

confidence: 99%

High-Pressure-Limit and Pressure-Dependent Rate Rules for Unimolecular Reactions Related to Hydroperoxy Alkyl Radicals in Normal-Alkyl Cyclohexane Combustion. 2. Cyclization Reaction Class

Yao

Pang²,

et al. 2021

J. Phys. Chem. A

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The hydroperoxy alkyl radicals are important intermediates in the low-temperature combustion for normal-alkyl cycloalkanes, and the cyclization reactions of hydroperoxy alkyl radicals to form cyclic ethers are responsible for a major fraction of the OH formation, which has the potential to promote ignition. In most of the previous modeling studies for normal-alkyl cycloalkane combustion, the kinetic data of the cyclization reactions in the detailed combustion mechanism were mainly taken from the analogous reactions in cyclohexane, methyl cyclohexane, and alkanes in published literature studies. In this work, the kinetics of the cyclization reaction class of hydroperoxy alkyl radicals in normal-alkyl cycloalkanes is studied, where the reaction class is divided into subclasses depending upon the ring size of the transition states, the types of the carbons on which the −OOH site is located and the types of the carbons on which the radical site is located, and the positions of the cyclization (on the alkyl side chain, on the cycle, or between the alkyl side chain and the cycle). Energy barriers and high-pressure-limit site rate constants and pressure-dependent rates for reactions in all subclasses are calculated, and rate rules for all subclasses are developed. The high-pressure-limit rate constants are determined from CBS-QB3 electronic structure calculations combined with canonical transition-state theory calculations, and pressure-dependent rate constants are calculated by using the Rice–Ramsberger–Kassel–Marcus/Master Equation theory at pressures varying from 0.01 to 100 atm. Comparisons of the rate constants for cyclization reactions of hydroperoxy alkyl cyclohexylperoxy radicals calculated in this work with the values of the corresponding reactions in some of the popular combustion mechanisms show that it is unreasonable to use the kinetic data of analogous reactions in alkanes, cyclohexanes, or smaller normal-alkyl cyclohexanes. Therefore, the accurate kinetic calculations and the construction of rate rules for normal-alkyl cycloalkanes are necessary and significant for the reliable modeling of the low-temperature combustion of normal-alkyl cyclohexanes.

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“…For example, Zou et al have constructed a detailed combustion mechanism for ethyl cyclohexane at low temperature, where the rate constants of these two classes are estimated by analogy to corresponding reactions in cyclohexane, methyl cyclohexane, and alkanes. Mao et al , have constructed a detailed combustion mechanism for n -butyl cyclohexane over low-to-high temperature ranges, where the rate constants of the concerted HO 2 elimination from ROO radicals and the β - scission of the C–OOH bond from QOOH radicals are estimated based on the analogies of cyclohexane and methyl cyclohexane when reactions occur on the cycle, and the rate constants were taken from the analogies of alkanes according to the carbon type when reactions occur on the alkyl side chain. However, in our previous study of the intramolecular H-migration reactions of normal alkyl cyclohexylperoxy radicals, it has been shown that there are large differences in the rate constants between similar reactions in alkyl cycloalkanes and alkanes.…”

Section: Introductionmentioning

confidence: 99%

High-Pressure-Limit and Pressure-Dependent Rate Rules for Unimolecular Reactions Related to Hydroperoxy Alkyl Radicals in Normal Alkyl Cyclohexane Combustion. 1. Concerted HO₂ Elimination Reaction Class and β-Scission Reaction Class

Yao

Pang²,

et al. 2021

J. Phys. Chem. A

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The reactions of the concerted HO2 elimination from alkyl peroxy radicals and the β-scission of the C–OOH bond from hydroperoxy alkyl radicals, which lead to the formation of olefins and HO2 radicals, are two important reaction classes that compete with the second O2 addition step of hydroperoxy alkyl radicals, which are responsible for the chain branching in the low-temperature oxidation of normal alkyl cycloalkanes. These two reaction classes are also believed to be responsible for the negative temperature coefficient behavior due to the formation of the relatively unreactive HO2 radical, which has the potential to inhibit ignition of normal alkyl cycloalkanes. In this work, the kinetics of the above two reaction classes in normal alkyl cycloalkanes are studied, where reactions in the concerted elimination class are divided into subclasses depending upon the types of carbons from which the H atom is eliminated and the positions of the reaction center (on the alkyl side chain or on the cycle), and the reactions in the β-scission reaction class are divided into subclasses depending upon the types of the carbons on which the radical is located and the positions of the reaction center. Energy barriers by using quantum chemical methods at the CBS-QB3 level, high-pressure-limit rate constants by using canonical transition state theory, and pressure-dependent rate constants at pressures from 0.01 to 100 atm by using Rice–Ramsberger–Kassel–Marcus/Master Equation theory are calculated for a representative set of reactions from methyl cyclohexane to n-butyl cyclohexane in each subclass, from which high-pressure-limit rate rules and pressure-dependent rate rules for each subclass are derived from the average rate constants of reactions within each subclass. A comparison of the rate constants for the reactions in the two reaction classes calculated in this work is made with the rate constants of the same reactions from available mechanisms published in the literature, where most of the rate constants are approximately estimated from analogous reactions in alkanes or small alkyl cyclohexanes, and it is found that a large difference may exist between them, indicating that the present work, which provides more accurate kinetic parameters and reasonable rate rules for these reaction classes, can be helpful to construct higher-accuracy mechanism models for normal alkyl cyclohexane combustion.

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A detailed chemical mechanism for low to high temperature oxidation of n-butylcyclohexane and its validation

Cited by 24 publications

References 75 publications

A detailed chemical kinetic modeling and experimental investigation of the low‐ and high‐temperature chemistry of n‐butylcyclohexane

A detailed chemical kinetic modeling and experimental investigation of the low‐ and high‐temperature chemistry of n‐butylcyclohexane

High-Pressure-Limit and Pressure-Dependent Rate Rules for Unimolecular Reactions Related to Hydroperoxy Alkyl Radicals in Normal-Alkyl Cyclohexane Combustion. 2. Cyclization Reaction Class

High-Pressure-Limit and Pressure-Dependent Rate Rules for Unimolecular Reactions Related to Hydroperoxy Alkyl Radicals in Normal Alkyl Cyclohexane Combustion. 1. Concerted HO₂ Elimination Reaction Class and β-Scission Reaction Class

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A detailed chemical mechanism for low to high temperature oxidation of n-butylcyclohexane and its validation

Cited by 24 publications

References 75 publications

A detailed chemical kinetic modeling and experimental investigation of the low‐ and high‐temperature chemistry of n‐butylcyclohexane

A detailed chemical kinetic modeling and experimental investigation of the low‐ and high‐temperature chemistry of n‐butylcyclohexane

High-Pressure-Limit and Pressure-Dependent Rate Rules for Unimolecular Reactions Related to Hydroperoxy Alkyl Radicals in Normal-Alkyl Cyclohexane Combustion. 2. Cyclization Reaction Class

High-Pressure-Limit and Pressure-Dependent Rate Rules for Unimolecular Reactions Related to Hydroperoxy Alkyl Radicals in Normal Alkyl Cyclohexane Combustion. 1. Concerted HO2 Elimination Reaction Class and β-Scission Reaction Class

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High-Pressure-Limit and Pressure-Dependent Rate Rules for Unimolecular Reactions Related to Hydroperoxy Alkyl Radicals in Normal Alkyl Cyclohexane Combustion. 1. Concerted HO₂ Elimination Reaction Class and β-Scission Reaction Class