Structure-reactivity trends of C1-C4 alkanoic acid methyl esters

被引:69
作者
Akih-Kumgeh, Benjamin [1 ]
Bergthorson, Jeffrey M. [1 ]
机构
[1] McGill Univ, Dept Mech Engn, Montreal, PQ H3A 2K6, Canada
基金
加拿大自然科学与工程研究理事会;
关键词
Methyl esters; Shock tube ignition; Biodiesel surrogates; Oxygenated hydrocarbons; Rate parameters; ATMOSPHERIC OXIDATION MECHANISM; KINETIC REACTION-MECHANISM; IGNITION DELAY TIMES; SHOCK-TUBE; RATE CONSTANTS; N-HEPTANE; ABSTRACTION REACTIONS; HYDROGEN ABSTRACTION; COMBUSTION CHEMISTRY; HYDROCARBONS;
D O I
10.1016/j.combustflame.2010.10.021
中图分类号
O414.1 [热力学];
学科分类号
摘要
Structure-reactivity trends are investigated by means of high temperature shock tube ignition and quantum chemical calculations for four alkanoic acid methyl esters methyl formate (MF), methyl acetate (MA), methyl propanoate (MP), and methyl butanoate (MB). Ignition delay times are compared at constant argon/oxygen ratios, equivalence ratios and average pressures. It is observed that MA consistently shows longer ignition delay times than the other three esters, while MF and MB have comparable ignition delay times but different activation energies. MP ignition delay times are also comparable with MB in most cases but are found to be slightly shorter, especially under lean conditions. Simulated ignition delay times using the chemical kinetic model by Westbrook et al. [1] also show that MA has longer ignition delay times than MF, although the agreement between model prediction and experiment for MA is not as good as that for MF at 10 atm. Simulated ignition delay times for MB using two recent MB chemical kinetic models do not predict the same ignition delay times as the small ester mechanism under conditions where MF and MB experimental ignition delay times are found to be comparable. Ab initio quantum mechanical calculations are performed using the composite method CBS QB3, in order to determine bond dissociation energies for the four esters, as well as activation barriers for possible fuel H-abstraction reactions by H atoms. The concerted unimolecular decomposition of the esters to yield methanol and a ketene (or CO in the case of MF) is also studied. The relative reactivity observed in experiments for the four esters can be partially attributed to differences in bond energies and the calculated rates obtained in this study. Further work on possible reaction pathways and subsequent reactions of resulting primary radicals from small methyl esters is motivated by this study. (C) 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
引用
收藏
页码:1037 / 1048
页数:12
相关论文
共 51 条
[1]   Comparative Study of Methyl Butanoate and n-Heptane High Temperature Autoignition [J].
Akih-Kumgeh, Benjamin ;
Bergthorson, Jeffrey M. .
ENERGY & FUELS, 2010, 24 (04) :2439-2448
[2]   Shock Tube Study of Methyl Formate Ignition [J].
Akih-Kumgeh, Benjamin ;
Bergthorson, Jeffrey M. .
ENERGY & FUELS, 2010, 24 (01) :396-403
[3]  
Benson SW., 1976, Thermochemical kinetics: methods for the estimation of thermochemical data and rate parameters, V2d
[4]   SHOCK-TUBE INVESTIGATION OF COMPARATIVE IGNITION DELAY TIMES FOR C1-C5 ALKANES [J].
BURCAT, A ;
SCHELLER, K ;
LIFSHITZ, A .
COMBUSTION AND FLAME, 1971, 16 (01) :29-&
[5]   Rate constants for the H abstraction from alkanes (R-H) by R′O•2 radicals:: A systematic study on the impact of R and R′ [J].
Carstensen, Hans-Heinrich ;
Dean, Anthony M. ;
Deutschmann, Olaf .
PROCEEDINGS OF THE COMBUSTION INSTITUTE, 2007, 31 :149-157
[6]   Rate constants for the abstraction reactions RO2 + C2H6; R = H, CH3, and C2H5 [J].
Carstensen, HH ;
Dean, AM .
PROCEEDINGS OF THE COMBUSTION INSTITUTE, 2005, 30 :995-1003
[7]   Atmospheric oxidation mechanism of methyl propionate [J].
Cavalli, F ;
Barnes, I ;
Becker, KH ;
Wallington, TJ .
JOURNAL OF PHYSICAL CHEMISTRY A, 2000, 104 (48) :11310-11317
[8]   Atmospheric oxidation mechanism of methyl acetate [J].
Christensen, LK ;
Ball, JC ;
Wallington, TJ .
JOURNAL OF PHYSICAL CHEMISTRY A, 2000, 104 (02) :345-351
[9]   A comprehensive modeling study of n-heptane oxidation [J].
Curran, HJ ;
Gaffuri, P ;
Pitz, WJ ;
Westbrook, CK .
COMBUSTION AND FLAME, 1998, 114 (1-2) :149-177
[10]   Autoignition measurements and a validated kinetic model for the biodiesel surrogate, methyl butanoate [J].
Dooley, S. ;
Curran, H. J. ;
Simmie, J. M. .
COMBUSTION AND FLAME, 2008, 153 (1-2) :2-32