Improvement of the Modeling of the Low-Temperature Oxidation ofn-Butane: Study of the Primary Reactions

Abstract

This paper revisits the primary reactions involved in the oxidation of n-butane from low to intermediate temperatures (550-800 K) including the negative temperature coefficient (NTC) zone. A model that was automatically generated is used as a starting point and a large number of thermochemical and kinetic data are then re-estimated. The kinetic data of the isomerization of alkylperoxy radicals giving (•)QOOH radicals and the subsequent decomposition to give cyclic ethers has been calculated at the CBS-QB3 level of theory. The newly obtained model allows a satisfactory prediction of experimental data recently obtained in a jet-stirred reactor and in rapid compression machines. A considerable improvement of the prediction of the selectivity of cyclic ethers is especially obtained compared to previous models. Linear and global sensitivity analyses have been performed to better understand which reactions are of influence in the NTC zone.

Revisiting the Kinetics and Thermodynamics of the Low-Temperature Oxidation Pathways of Alkanes: A Case Study of the Three Pentane Isomers

“…These investigations were undertaken in light of recent experimental data detailing several intermediate species produced from the low-temperature oxidation of propane, n-butane, and n-heptane, using advanced analytical techniques. [33][34][35][36][37][38] These oxygenated intermediates include ketones, diones, and organic acids, and are formed primarily at quite low temperatures (<650 K). The reaction classes investigated were (1) show that, at 650 K, 94% of C 7 carbonyl-hydroperoxides decompose via simple fission of the O-O bond in the hydroperoxyl group.…”

A theoretical study of cyclic ether formation reactions

“…In recent years, there has been a proliferation of systematic theoretical studies concerning reaction pathways of importance in the low-temperature oxidation of alkanes [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] . The rapid increase in the number of studies of this kind is due, in part, to more readily available computational resources.…”

“…Solid black: this work , dashed black: Villano et al . [1] , dotted black: Miyoshi [2] , dash-dot black: Wijaya et al [3] , solid grey: Cord et al [4] ,. dashed grey: Chan et al[5] , dotted grey: Goldsmith et al[6] .…”

Modeling Combustion with Detailed Kinetic Mechanisms

“…More accurate correlations have been recently proposed based on theoretical calculations (e.g. Sharma et al (2010), Cord et al (2012a)). • Formation of cyclic ethers (class 23) An example of this reaction class is shown in Fig.…”

“…Curran et al 1998, Ranzi et al 2001, Buda et al 2005, the rate constant for this type of reaction depends only on the size of the ring which is formed. However, recent work (Cord et al 2012a) has shown the need to differentiate the type of carbon atom involved in the ring closure. The values proposed by Curran et al (1998) for the formation of furans, the types of cyclic ethers which are formed in larger amounts as shown by experiments, is k 23 , furan = 9.4 9 10 9 exp(-3.5/T) s -1 .…”