On the H-atom abstractions from C1-C4 alcohols, aldehydes, and ethers by NO2: ab initio and comprehensive kinetic modeling

TL;DR

This study comprehensively investigates H-atom abstraction by NO2 from C1-C4 alcohols, aldehydes, and ethers using ab initio calculations and kinetic modeling, revealing significant impacts on combustion ignition delay times.

Contribution

It provides new detailed kinetic parameters for NO2 H-atom abstraction from alcohols, aldehydes, and ethers, enhancing combustion models and understanding of NOX-hydrocarbon interactions.

Findings

Adding H-atom abstraction reactions reduces ignition delay times.

Sensitivity analysis shows H abstraction by NO2 is a key reaction.

Accurate kinetic parameters improve combustion model predictions.

Abstract

As crucial additives and intermediate, alcohols, ethers, and aldehydes play a significant role in the combustion process. However, the chemistry of NOXhydrocarbon interactions and the rate rules governing these interactions remain largely unexplored in this combustion system. To address this gap, this study provides a comprehensive investigation of H-atom abstraction by NO2 from C1-C4 alcohols, aldehydes and ethers that leads to the formation of 3 HNO2 isomers (i.e., transHONO, HNO2, and cisHONO), encompassing 9 hydrocarbons and 45 reactions. Utilizing the DLPNO CCSD(T)cc pVDZ M06 2X 6 311g d,p method, the electronic structures, single point energies, C H bond dissociation energies and 1 D hindered rotor potentials of the reactants, transition states, complexes and products in each reaction are computed. Adding these H atom abstractions to the chemical kinetic model improves the model reactivity and advances the ignition, as indicated by the reduction in ignition delay time for species that initially lacked these reactions. Further sensitivity and flux analyses highlight the crucial role of H atom abstraction by NO2. The findings underscore the importance of accurately incorporating these kinetic parameters into newly developed chemical models for alcohols, aldehydes, and ethers. Additionally, the study highlights the need for future experimental efforts to investigate the effects of NO2 on the combustion systems of these compounds.