Thermochemistry and kinetics of the alpha- and betahydroxyethyl radical + O2 reactions in ethanol combustion

Document Type

Conference Proceeding

Publication Date

1-1-2007

Abstract

Bioethanol is emerging as a component that will be increasingly blended into traditional petroleum-derived gasoline. It is important that we have accurate kinetic models for the combustion of ethanol in order to better understand the impact of this renewable fuel blend component in current and future engines. We have studied the reaction of the alpha- and betahydroxyethyl radicals with O2 using theoretical density functional theory and ab initio methods. Detailed potential energy surfaces for these reactions are presented, with rate parameters calculated for each reaction step from transition state theory. The chemically activated hydroxyethyl + O2 systems are modeled using quantum Rice-Ramsperger-Kassel (QRRK) theory, with master equation analysis for falloff. Major products in the β-hydroxyethyl radical + O2 reaction include formaldehyde, vinyl alcohol, and at low temperatures and high pressures the stabilized β-hydroxyethylperoxy radical. The α-hydroxyethyl + O2 reaction proceeds almost exclusively to acetaldehyde + HO2 via a low-barrier H2O elimination from the hydroxyethylpeoxy adduct. The introduction of the rate constants presented in this study into existing reaction mechanisms should lead to better kinetic models for ethanol combustion.

Identifier

84888015160 (Scopus)

ISBN

[9781604238112]

Publication Title

5th US Combustion Meeting 2007

First Page

1378

Last Page

1392

Volume

3

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