Theoretical kinetic studies on intramolecular H-migration reactions of peroxy radicals of diethoxymethane

Diethoxymethane (DEM), a promising carbon-neutral fuel, has high reactivity at low temperatures. The intramolecular hydrogen migration reaction of the DEM peroxy radicals can be viewed as a critical step in the low temperature oxidation mechanism of DEM. In this work, multistructural transition stat...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2024-09, Vol.26 (37), p.24676-24688
Main Authors: Chen, Siyu, Li, Juanqin, Zhu, Quan, Li, Zerong
Format: Article
Language:English
Subjects:
Anharmonicity
Hydrogen bonding
Kinetics
Low temperature
Oxidation
Peroxy radicals
Pressure dependence
Pressure effects
Rate constants
Reaction kinetics
Spontaneous combustion
Steric hindrance
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Summary:Diethoxymethane (DEM), a promising carbon-neutral fuel, has high reactivity at low temperatures. The intramolecular hydrogen migration reaction of the DEM peroxy radicals can be viewed as a critical step in the low temperature oxidation mechanism of DEM. In this work, multistructural transition state theory (MS-TST) was utilized to calculate the high-pressure limit rate constants of 1,5, 1,6 and 1,7 H-migration reactions for DEM peroxy radicals. In addition to the tunneling effects and anharmonic effects, the intramolecular effects, including steric hindrance, intramolecular hydrogen bonding and conformational changes in reactants and transition states, are also considered in the rate constant calculations. The calculated energy barriers and rate constants demonstrated the substantial impact of intramolecular effects on the kinetics of H-migration reactions in DEM peroxy radicals. Specifically, the distinct configurations of transition states could potentially influence the reaction kinetics. The pressure-dependent rate constants are computed using system-specific quantum RRK theory. The calculated results show that the falloff effect of 1,5 and 1,6 H-migration reactions is more pronounced than that of the 1,7 H-migration reaction. The thermodynamics and kinetics presented in this study could be instrumental in understanding the low-temperature oxidation mechanism of DEM and might prove crucial for future research on comprehensively analyzing the autoignition behavior.
ISSN:1463-9076
1463-9084
1463-9084
DOI:10.1039/d4cp02302a