Mechanistic and mathematical modeling of the thermal decompostion of cyclohexane

Aribike, D.S.; Susu, Alfred A.; Ogunye, A. F.

doi:10.1016/0040-6031(81)85152-0

Cited by 19 publications

(9 citation statements)

References 17 publications

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“…Tsang [29] and Brown et al [30] proposed that the dominant initial channel of cyclohexane pyrolysis is its isomerization to form 1-hexene. However, the experimental results in an annular reactor at atmospheric pressure obtained by Aribike et al [31] did not confirm Tsang's prediction [29], since 1-hexene was not observed. Voisin et al [8] performed a measurement for the oxidation of cyclohexane in a jet stirred reactor (JSR) at 10 atm, in which 1-hexene was also not identified.…”

Section: Introductioncontrasting

confidence: 42%

“…In their experiments, 1-hexene was observed at 1 atm, but not at 10 atm. Dissociation channels other than isomerization reaction of cyclohexane were proposed by Aribike et al [31], Voisin et al [8] and EI Bakali et al [9] due to the absence of 1-hexene. Recently, Kiefer et al [5] carried out shock tube and theoretical study of cyclohexane decomposition.…”

Section: Introductionmentioning

confidence: 99%

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An experimental and kinetic modeling study of cyclohexane pyrolysis at low pressure

Wang

Cheng

Yuan

et al. 2012

Combustion and Flame

113

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a b s t r a c tThe pyrolysis of cyclohexane at low pressure (40 mbar) was studied in a plug flow reactor from 950 to 1520 K by synchrotron VUV photoionization mass spectrometry. More than 30 species were identified by measurement of photoionization efficiency (PIE) spectra, including some radicals like methyl, propargyl, allyl and cyclopentadienyl radicals, and stable products (e.g., 1-hexene, benzene and some aromatics). Among all the products, 1-hexene is formed at the lowest temperature, indicating that the isomerization of cyclohexane to 1-hexene is the dominant initial decomposition channel under the condition of our experiment. We built a kinetic model including 148 species and 557 reactions to simulate the experimental results. The model satisfactorily reproduced the mole fraction profiles of most pyrolysis products. The rate of production (ROP) analysis at 1360 and 1520 K shows that cyclohexane is consumed mainly through two reaction sequences: cyclohexane ? 1-hexene ? allyl radical + n-propyl radical, and cyclohexane ? cyclohexyl radical ? hex-5-en-1-yl radical that further decomposes to 1,3-butadiene via hex-1-en-3-yl and but-3-en-1-yl radicals.

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Section: Introductioncontrasting

confidence: 42%

Section: Introductionmentioning

confidence: 99%

An experimental and kinetic modeling study of cyclohexane pyrolysis at low pressure

Wang

Cheng

Yuan

et al. 2012

Combustion and Flame

113

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“…More recently, Aribike et al , studied cyclohexane dissociation in an annular flow reactor over 1000−1300 K with 1 atm of N 2 as the bath gas. They proposed the alternative reactions c-C 6 H 12 → 3C 2 H 4 c-C 6 H 12 → 2C 3 H 6 c-C 6 H 12 → C 4 H 6 + C 2 H 4 + H 2 whereas Tsang’s proposed diradical pathway, reactions and , was supported by Brown and co-workers, who studied the decomposition of cyclohexane at temperatures of 900−1200 K using the very low pressure pyrolysis (VLPP) technique.…”

Section: Introductionmentioning

confidence: 99%

Shock Tube and Theory Investigation of Cyclohexane and 1-Hexene Decomposition

et al. 2009

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The decomposition of cyclohexane (c-C(6)H(12)) was studied in a shock tube using the laser-schlieren technique over the temperature range 1300-2000 K and for 25-200 Torr in mixtures of 2%, 4%, 10%, and 20% cyclohexane in Kr. Vibrational relaxation of the cyclohexane was also examined in 10 experiments covering 1100-1600 K for pressures below 20 Torr, and relaxation was found to be too fast to allow resolution of incubation times. The dissociation of 1-hexene (1- C(6)H(12)), apparently the sole initial product of cyclohexane decomposition, was also studied over 1220-1700 K for 50 and 200 Torr using 2% and 3% 1-hexene in Kr. On heating, cyclohexane simply isomerizes to 1-hexene, and this then dissociates almost entirely by a more rapid C-C scission to allyl and n-propyl radicals. This two-step reaction results in an initial small density gradient from the slight endothermicity of the isomerization. The gradient then rises strongly as the product 1-hexene dissociates. For the lower temperatures, this behavior is fully resolved here. For the higher pressures, 1-hexene decomposition generates negative gradients (exothermic reaction) as the radicals formed begin to recombine. Cyclohexane also generates such gradients, but these are now much smaller because the radical pool is depleted by abstraction from the reactant. A complete mechanism for the 1-hexene decomposition and for that of cyclohexane involving 79 reactions and 30 species is used in the final modeling of the gradients. Rate constants and RRKM fit parameters for the initial reactions are provided for the entire range of conditions. The possibility of direct reaction to allyl and n-propyl radicals, without stabilization of the intermediate 1-hexene, is examined down to pressures as low as 25 Torr, without a clear resolution of the issue. High-pressure limit rate constants from RRKM extrapolation are k(infinity)(c-C(6)H(12) --> 1-C(6)H(12)) = (8.76 x 10(17)) exp((-91.94 kcal/mol)/RT) s(-1) (T = 1300-2000 K) and k(infinity)(1-C(6)H(12) --> (*)C(3)H(7) + (*)C(3)H(5)) = (1.46 x 10(16)) exp((-69.12 kcal/mol)/RT) s(-1) (T = 1200-1700 K). This high-pressure rate for cyclohexane is entirely consistent with the notion that the isomerization involves initial C-C fission to a diradical. These extrapolated high-pressure rates are in good agreement with much of the literature.

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“…[1][2][3][4][5] Many studies have been reported on the thermal decomposition mechanism of cyclohexane and its isomer 1-hexene. [6][7][8][9][10][11][12][13][14][15][16] While the investigations on cycloheptane and its isomer 1-heptene are much less than those of cyclohexane. Gusel'nikov et al examined the very low-pressure pyrolysis (VLPP) coupled with low temperature matrix infrared spectroscopy method of cycloheptane and 1-heptene.…”

Section: Introductionmentioning

confidence: 99%

Flash pyrolysis vacuum ultraviolet photoionization mass spectrometry of cycloheptane: A study of the initial decomposition mechanism

Shao

Sun

Gomez

et al. 2022

Eur J Mass Spectrom (Chichester)

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Thermal decomposition of cycloheptane was studied using flash pyrolysis coupled with vacuum ultraviolet (118.2 nm) single photon ionization time-of-flight mass spectrometry at temperatures ranging from 295 K to 1380 K. C-C bond breaking of cycloheptane leading to the 1,7-heptyl diradical was considered as the initiation step. The 1,7-heptyl diradical could readily isomerize to 1-heptene and decompose into several fragments, with dissociation to •C4H9 and •C3H5 as the predominant product channel. The 1,7-heptyl diradical could undergo direct dissociation, as evidenced by the production of the C5H10 species. Quantum chemistry calculations at UCCSD(T)/cc-pVDZ//UB3LYP/cc-pVDZ level of theory on the initial reaction pathways of cycloheptane were also carried out to support the experimental observations. Other possible initiation channels, as well as some secondary reaction products, were also identified.

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Mechanistic and mathematical modeling of the thermal decompostion of cyclohexane

Cited by 19 publications

References 17 publications

An experimental and kinetic modeling study of cyclohexane pyrolysis at low pressure

An experimental and kinetic modeling study of cyclohexane pyrolysis at low pressure

Shock Tube and Theory Investigation of Cyclohexane and 1-Hexene Decomposition

Flash pyrolysis vacuum ultraviolet photoionization mass spectrometry of cycloheptane: A study of the initial decomposition mechanism

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