TY - JOUR
T1 - Reaction of Hydroperoxy Radicals with Primary C1-5 Alcohols
T2 - A Profound Effect on Ignition Delay Times
AU - Rawadieh, Saleh E.
AU - Altarawneh, Ibrahem S.
AU - Batiha, Mohammad A.
AU - Al-Makhadmeh, Leema A.
AU - Almatarneh, Mansour H.
AU - Altarawneh, Mohammednoor
N1 - Publisher Copyright:
Copyright © 2019 American Chemical Society.
PY - 2019/11/21
Y1 - 2019/11/21
N2 - Ignition delay times of primary alcohols often display a noticeable sensitivity to their initial reactions with HO2 radicals. In view of the transient nature of HO2 radicals, kinetic models on combustion of alcohols utilize theoretically obtained constant parameters for the abstraction HO2 + alcohols reactions. Rate constants for the title reactions in pertinent kinetic models are often extrapolated from analogous computed values for either alkanes + HO2 or n-butane + HO2 reactions. Even for the simplest alcohol, methanol, literature values for the reaction rate constants considerably vary within one order of magnitude. Herein, we compute reaction rate constants for H abstraction from the weakest sites in primary C1-5 alcohols by HO2 (methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, t-butanol, n-pentanol, and i-pentanol). In most cases, our reaction rate coefficients tend to slightly exceed corresponding values deployed in pertinent kinetic models. We have thoroughly assessed the predictive performance of literature kinetic models in computing ignition delay times of these alcohols based on the updated rate constants for HO2-abstraction reactions. In the case of methanol, updating kinetic parameters for the reaction CH3OH + HO2 → CH2OH + H2O2 improves prediction of ignition delay times at lower temperatures in reference to original literature kinetic models. Likewise, a modified kinetic model for n-butane and t-butanol affords better agreement with experimental values of ignition delay times at low temperatures and high pressures. Kinetic parameters presented herein will be useful to accurately account for salient oxidation features of alcohols in real combustion engines.
AB - Ignition delay times of primary alcohols often display a noticeable sensitivity to their initial reactions with HO2 radicals. In view of the transient nature of HO2 radicals, kinetic models on combustion of alcohols utilize theoretically obtained constant parameters for the abstraction HO2 + alcohols reactions. Rate constants for the title reactions in pertinent kinetic models are often extrapolated from analogous computed values for either alkanes + HO2 or n-butane + HO2 reactions. Even for the simplest alcohol, methanol, literature values for the reaction rate constants considerably vary within one order of magnitude. Herein, we compute reaction rate constants for H abstraction from the weakest sites in primary C1-5 alcohols by HO2 (methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, t-butanol, n-pentanol, and i-pentanol). In most cases, our reaction rate coefficients tend to slightly exceed corresponding values deployed in pertinent kinetic models. We have thoroughly assessed the predictive performance of literature kinetic models in computing ignition delay times of these alcohols based on the updated rate constants for HO2-abstraction reactions. In the case of methanol, updating kinetic parameters for the reaction CH3OH + HO2 → CH2OH + H2O2 improves prediction of ignition delay times at lower temperatures in reference to original literature kinetic models. Likewise, a modified kinetic model for n-butane and t-butanol affords better agreement with experimental values of ignition delay times at low temperatures and high pressures. Kinetic parameters presented herein will be useful to accurately account for salient oxidation features of alcohols in real combustion engines.
UR - http://www.scopus.com/inward/record.url?scp=85074233938&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85074233938&partnerID=8YFLogxK
U2 - 10.1021/acs.energyfuels.9b02169
DO - 10.1021/acs.energyfuels.9b02169
M3 - Article
AN - SCOPUS:85074233938
SN - 0887-0624
VL - 33
SP - 11781
EP - 11794
JO - Energy and Fuels
JF - Energy and Fuels
IS - 11
ER -