Pyrolysis and combustion chemistry of tetrahydropyran: Experimental and modeling study

Tran, Luc-Sy; Bruycker, Ruben De; Carstensen, Hans-Heinrich; Glaude, Pierre‐Alexandre; Monge, Fabiola; Alzueta, María U.; Martin, Roberto Colino; Battin‐Leclerc, Frédérique; Geem, Kevin Van; Marin, Guy

doi:10.1016/j.combustflame.2015.07.030

Cited by 19 publications

(48 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1 ). On a per-C-H bond basis, the branching ratio is approximated as α: β: γ = 0.76:0.16:0.08 (Supplemental Material S4), similar to the distribution predicted in the comprehensive chemical kinetics model in [9] . Using a different method of approximation, the α radical remains dominant in H-abstraction reactions from tetrahydropyran by OH [14] .…”

Section: Initial Radical Distribution From Tetrahydropyran + CL Reactmentioning

confidence: 99%

“…Dagaut et al [7] report a comprehensive chemical kinetics model developed for 2-10 atm and 800-1700 K. Tran et al [9] studied the pyrolysis and high-temperature ignition and flame properties of tetrahydropyran and constructed a comprehensive chemical kinetics model covering a broader parameter space in temperature, pressure, and fuel concentration.…”

Section: Introductionmentioning

confidence: 99%

“…Three combustion-related studies on tetrahydropyran exist, which focus on high-temperature measurements, namely ignition delay times and jet-stirred reactor species profiles [7] , speciation in low-pressure flames [8] , and pyrolysis, flame speciation, burning velocities, and ignition delay times [9] . Dagaut et al [7] report a comprehensive chemical kinetics model developed for 2-10 atm and 800-1700 K. Tran et al [9] studied the pyrolysis and high-temperature ignition and flame properties of tetrahydropyran and constructed a comprehensive chemical kinetics model covering a broader parameter space in temperature, pressure, and fuel concentration.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Influence of oxygenation in cyclic hydrocarbons on chain-termination reactions from R + O2: tetrahydropyran and cyclohexane

Rotavera

Savee

Antonov

et al. 2017

Proceedings of the Combustion Institute

View full text Add to dashboard Cite

Multiplexed photoionization mass spectrometry (MPIMS) is used to determine branching fractions of conjugate alkenes from R + O 2 oxidation reactions for cyclohexane ( c -C 6 H 12 ) and tetrahydropyran ( c -C 5 H 10 O), a lignocellulosic-derived oxygenated biofuel. Because conjugate alkene formation is coincident with the formation of HO 2 , the results reveal the temperature-and pressure-dependent influence of the oxygen heteroatom on chain-termination propensity. The experiments were conducted using Cl-initiated oxidation at 10 and 1520 Torr and from 500 to 700 K, and ab initio calculations of bond energies, saddle point energies, and rate coefficients of unimolecular decomposition of α-tetrahydropyranyl were conducted to complement the experiments.Relative to the initial radical concentration [R] 0 the trend in conjugate alkene branching fraction exhibits monotonic positive temperature dependence in both cyclohexane and tetrahydropyran, except for the latter species at 10 Torr where increasing the temperature to 700 K caused an appreciable decrease. The decrease in the branching fraction with increasing temperature in tetrahydropyran oxidation occurs because ring-opening rates of α-tetrahydropyranyl radicals, enabled by weak C-O bond dissociation energies, exceed rates of O 2 -addition. Ring-opening rate coefficients for α-tetrahydropyranyl, computed from stationary points at the CCSD(T)-F12a/cc-PVDZ//M06-2X/6-311 ++ G * * level of theory, confirm that ring-opening at 700 K is favorable and higher oxygen concentrations are required for O 2 -addition rates to be significant. With increased temperature and lower [O 2 ], α-tetrahydropyranyl radicals preferentially undergo unimolecular decomposition into the linear radical ˙ C H 2 ( C H 2 ) 3 CHO . Conjugate alkene branching fractions measured at 1520 Torr for both cyclohexane and tetrahydropyran followed monotonic positive temperature dependence. The change in the tetrahydropyran trend at 1520 Torr relative to the 10 Torr measurements is ascribed to the increase in oxygen concentration mitigating ring-opening reactions of the initial R radicals.In contrast to the results at higher temperature, where ring-opening of tetrahydropyranyl radicals interrupts R + O 2 chemistry and reduces the formation of conjugate alkenes, branching fractions measured below 700 K were higher in tetrahydropyran compared to cyclohexane at 10 Torr. The difference suggests BRotave@Sandia.gov (B. Rotavera), CATaatj@Sandia.gov (C.A. Taatjes). that the ether group renders chain-termination pathways more-facile. Saddle point energy calculations on the surfaces of equatorial ROO conformers reveal that the barrier height to direct HO 2 formation from α-tetrahydropyranylperoxy is lower by ca. 5 kcal/mol compared to cyclohexylperoxy at the CBS-QB3 level of theory, which facilitates low-temperature chain-termination.

show abstract

Section: Initial Radical Distribution From Tetrahydropyran + CL Reactmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of oxygenation in cyclic hydrocarbons on chain-termination reactions from R + O2: tetrahydropyran and cyclohexane

Rotavera

Savee

Antonov

et al. 2017

Proceedings of the Combustion Institute

View full text Add to dashboard Cite

show abstract

“…Rate constants for C-O and C-H bond β-scissions (channels Ia, Ic, IIa, and IIc in Fig. 1 ) and isomerization (channel "iso") were calculated here using the CBS-QB3 method; details of the used CBS-QB3 approach are given in [24] . The present model has used highpressure limiting rate constants for the unimolecular decomposition reactions of the fuel radicals.…”

Section: Model Development and Simulationsmentioning

confidence: 99%

“…Reactions of most of the primary products (ethylene, acetaldehyde, ethanol, formaldehyde, etc.) are already included in the reaction base and decomposition reactions of ethyl vinyl ether have been taken from [24] . Reactions of some products involved in low-temperature oxidation were newly added, and high-pressure limiting rate constants were used for unimolecular initiation reactions.…”

Section: Model Development and Simulationsmentioning

confidence: 99%