Constraining the Low-Temperature Oxidation Mechanism of n-Hexanol through the Detection and Identification of C6 Elusive Intermediates

Year: 2025

Type: article

Abstract: Alcohol-based fuels are currently considered to be viable energy carriers for the transportation sector. Consequently, a comprehensive mechanistic understanding of the low-temperature oxidation of alcohols is essential for application in advanced low-temperature compression engines. In this work, a multidimensional approach involving experimental investigations, kinetic modeling, and theoretical calculations was used to provide new insights into the low-temperature oxidation mechanism of a C 6 alcohol, n -hexanol (CH 3 (CH 2 ) 5 OH), through the detection and identification of elusive C 6 intermediates. The oxidation of n -hexanol was investigated in a jet-stirred reactor under stoichiometric conditions (ϕ = 1.0), an initial fuel concentration of 2%, a residence time of 2 s, a temperature range between 500 and 660 K, and a pressure of 700 Torr. The reactants, intermediates, and final products were detected and identified by means of molecular-beam mass spectrometry coupled with single-photon ionization employing tunable synchrotron-generated vacuum ultraviolet radiation. Chemical kinetic simulations were performed using a previously published kinetic model (Togbé et al., Energy Fuels 2010, 11, 5859−5875) to predict the reactivity of n -hexanol and elucidate the predominant formation pathways of the observed low-temperature species. Experimental photoionization efficiency curves in conjunction with ab initio calculations, enabled the identification of important low-temperature species, such as C 6 unsaturated alcohols, C 6 olefinic hydroperoxides, C 6 cyclic ethers, C 6 diones, and C 6 ketohydroperoxides. The results of this study provide valuable insight into the mechanism of the low-temperature oxidation chemistry of n -hexanol, contributing to the development of kinetic models for the low-temperature oxidation of n -hexanol and other long-chain linear alcohols.

Source: Energy & Fuels

DOI: 10.1021/acs.energyfuels.5c00887

Authors: Yitong Zhai, Alec C. DeCecco, Ahren W. Jasper, Nils Hansen, Philippe Dagaut, Giovani Villalobos, Denisia M. Popolan-Vaida

Institutions: University of Central Florida, Argonne National Laboratory, Sandia National Laboratories California, Sandia National Laboratories, Centre National de la Recherche Scientifique, Institut de Combustion Aérothermique Réactivité et Environnement

Language: English

Topic: Advanced Combustion Engine Technologies

Subfield: Fluid Flow and Transfer Processes

Field: Chemical Engineering

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: green

Funders: U.S. Department of Energy, University of Central Florida, Agence Nationale de la Recherche, Office of Science, National Nuclear Security Administration, Basic Energy Sciences, Argonne National Laboratory, Sandia National Laboratories

OpenAlex ID: W4411208984