Exploring the Chemical Kinetics of the First Oxygen Addition to Di-n-Propyl Ether Radicals at Low Temperatures

Abstract

Linear ethers are promising biomass fuels with high volume energy density and high cetane number that may be used directly as alternative fuels or fuel additives in internal combustion engines. In this work, the first O 2 addition reaction of the di-npropyl ether radical was investigated using high-level quantum chemical calculations combined with the Rice−Ramsperger− Kassel−Marcus theory to solve the master equation. The potential energy surfaces of di-n-propyl ether radicals (C 6 H 13 O) with O 2 were constructed at the QCISD(T)/CBS//M062X/6-311++G(d, p) level, and the rate constants were calculated for the pressure range of 0.1−100 atm and the temperature range of 300−1500 K and fitted by a modified Arrhenius formula. The calculations show that the consumption of di-n-propyl ether peroxyl radicals (C 6 H 13 O 3 ) via the five-membered ring or six-membered ring transition-state reaction channel is most favorable. In addition, the lowtemperature oxidation experiments of di-n-propyl ether were validated based on the calculations of the current work, and the results showed that the calculations were a good predictor of the experimental results.

Shock Tube/Laser Absorption Measurements of the High-Temperature Spectra and Decomposition of Propyl Ethers

“…The only available shock tube study was performed by Belmekki et al, where they measured the rate constants of H-abstraction reactions of DnPE by OH radicals over the temperature range of 865–1381 K and the pressure range of 0.96–5.56 bar. A theoretical study of H-abstraction reactions of DnPE by H, CH 3 , HO 2 , and OH radicals was performed by Gao et al He et al performed a theoretical study on the O 2 addition reaction of the DnPE radical. To the best of the authors’ knowledge, no other literature is available on the high-temperature kinetics of DnPE and DiPE, emphasizing the need to investigate the combustion kinetics of these isomers.…”

“…Oxidation studies of DnPE were conducted by Serinyel et al 10 and Belhadj et al 11 using a JSR. The only available shock tube study was performed by Belmekki et al, 12 Gao et al 13 He et al 14 performed a theoretical study on the O 2 addition reaction of the DnPE radical. To the best of the authors' knowledge, no other literature is available on the hightemperature kinetics of DnPE and DiPE, emphasizing the need to investigate the combustion kinetics of these isomers.…”

Theoretical and Modeling Study about the Low-Temperature Reaction Mechanism Between Oxymethylene Ether-2 (OME2) Radicals and O2

“…The fuel initially undergoes an H-abstraction reaction, producing fuel radicals that undergo an addition reaction with O 2 at low temperatures. Previous research work has focused on alkane and linear ether fuel radical addition reactions with O 2 . – It is therefore necessary to investigate the low-temperature oxidation of oxymethylene ether-2 (OME 2 ) in order to provide a predictive model for its future practical application and engine design.…”

“…Previous research work has focused on alkane and linear ether fuel radical addition reactions with O 2 . 19 – 21 It is therefore necessary to investigate the low-temperature oxidation of oxymethylene ether-2 (OME 2 ) in order to provide a predictive model for its future practical application and engine design.…”