Oxidation kinetics of n-pentanol: A theoretical study of the reactivity of the 1‑hydroxy‑1-peroxypentyl radical
Type
ArticleAuthors
Duan, YaozongMonge Palacios, Manuel
Grajales Gonzalez, Edwing

Han, Dong
Møller, Kristian H.

Kjaergaard, Henrik G.
Sarathy, Mani

KAUST Department
Chemical Engineering ProgramClean Combustion Research Center
Combustion and Pyrolysis Chemistry (CPC) Group
Physical Science and Engineering (PSE) Division
KAUST Grant Number
OSR-2016-CRG5-3022Date
2020-06-04Online Publication Date
2020-06-04Print Publication Date
2020-09Submitted Date
2019-12-01Permanent link to this record
http://hdl.handle.net/10754/663461
Metadata
Show full item recordAbstract
n-Pentanol has been considered as a promising alternative fuel for compression-ignition engines due to its potential to reduce greenhouse gases and pollutant emissions. Engine performance is strongly dominated by fuel oxidation chemistry, and thus a more accurate determination of the coefficients of the reactions ruling its oxidation is essential for the utilization of n-pentanol in combustion engines. The reactions involving 1‑hydroxy‑1-pentyl and molecular oxygen were found to play an important role in controlling the low temperature oxidation chemistry, but have not been investigated experimentally or theoretically; this is also the case for the reactions of the 1‑hydroxy‑1-peroxypentyl radical, which is formed by the addition of oxygen to the radical center of 1‑hydroxy‑1-pentyl. This work presents a theoretical study with high level ab initio calculations at the CCSD(T)/aug-cc-pVTZ//M06-2X/cc-pVTZ level of theory to shed light on the fate of the 1‑hydroxy‑1-peroxypentyl radical. The rate coefficients of all the possible intra-molecular hydrogen shift reactions of that radical were computed using variational transition state theory with small curvature tunneling corrections. For certain reactions, tunneling and variational effects are very pronounced, proving the need for robust methodologies to account for these effects. The hydrogen shift reaction leading to a concerted HO2 elimination and formation of n-pentanal is the dominant pathway and governs the reactivity of 1‑hydroxy‑1-peroxypentyl radical at any temperature. The reverse of this reaction was thereby investigated as well. For this prominent pathway, the effects of multistructural (multiple conformers) torsional anharmonicity of the stationary points were taken into account in order to refine the forward and reverse rate coefficients. The rate coefficients calculated at room temperature are compared to those calculated using a previously developed cost-effective multi-conformer transition state theory approach. The system-specific quantum Rice-Ramsperger-Kassel (SS-QRRK) theory was used to compute the pressure-dependent rate coefficients, which indicate significant pressure dependence at intermediate and high temperatures. Implementation of the calculated reaction rate coefficients in chemical kinetics models of n-pentanol revealed that our computed rate coefficients enable better insights into the chemistry of n-pentanol, and help to understand how n-pentanal is formed.Citation
Duan, Y., Monge-Palacios, M., Grajales-Gonzalez, E., Han, D., Møller, K. H., Kjaergaard, H. G., & Sarathy, S. M. (2020). Oxidation kinetics of n-pentanol: A theoretical study of the reactivity of the 1‑hydroxy‑1-peroxypentyl radical. Combustion and Flame, 219, 20–32. doi:10.1016/j.combustflame.2020.05.014Sponsors
The research at Shanghai Jiao Tong University was supported by funding from the National Natural Science Foundation of China under Grant No. 51776124. The present work was also supported by funding from King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under award No. OSR-2016-CRG5-3022. We would like to acknowledge resources of the Supercomputing Laboratory at KAUST. We are grateful for the funding from the Independent Research Fund Denmark, and the University of Copenhagen. The authors also would like to thank Prof. Heufer for providing us with the volume traces used in the RCM simulations.Publisher
Elsevier BVJournal
Combustion and FlameAdditional Links
https://linkinghub.elsevier.com/retrieve/pii/S0010218020301954ae974a485f413a2113503eed53cd6c53
10.1016/j.combustflame.2020.05.014