To improve the understanding of the unimolecular decomposition mechanism of nitroglycerin (NG) in the gas phase, density functional theory calculations were performed to determine various decomposition channels at the B3LYP/6-311G** level. For the unimolecular decomposition mechanism of NG, we find two main mechanisms: (I) homolytic cleavage of O-NO2 to form •NO2 and CH2ONO2CHONO2CH2O•, which subsequently decomposes to form •CHO, •NO2, and 2CH2O; (II) successive HONO eliminations to form HONO and CHO-CO-CHO, which subsequently decomposes to form CH2O + 2CO2 and •CHO + CO. We also find that the former channel has slightly smaller activation energy than the latter one. In addition, the rate constants of the initial process of the two decomposition channels were calculated. The results show that the O-NO2 cleavage pathway occurs more easily than the HONO elimination.
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http://dx.doi.org/10.1007/s00894-012-1724-5 | DOI Listing |
J Phys Chem A
December 2024
Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States.
Radical-radical reaction channels are important in the pyrolysis and oxidation chemistry of perfluoroalkyl substances (PFAS). In particular, unimolecular dissociation reactions within unbranched -perfluoroalkyl chains, and their corresponding reverse barrierless association reactions, are expected to be significant contributors to the gas-phase thermal decomposition of families of species such as perfluorinated carboxylic acids and perfluorinated sulfonic acids. Unfortunately, experimental data for these reactions are scarce and uncertain.
View Article and Find Full Text PDFJ Comput Chem
January 2025
Department of Chemistry, University of Hawaii, Honolulu, Hawaii, USA.
This computational study focuses on the mechanism of the consecutive decomposition of FOX-7 and compares the results with recent experimental study [J. Phys. Chem.
View Article and Find Full Text PDFJ Phys Chem A
December 2024
Chair of High Pressure Gas Dynamics, Shock Wave Laboratory, RWTH Aachen University, Aachen 52056, Germany.
In the search for alternative energy carriers that can replace conventional fossil fuels, sustainably produced oxygenated hydrocarbons represent a promising class of potential candidates. An illustrative member of this class of alternative biofuels are oxymethylene ethers (OMEs). This study makes a contribution to this objective by investigating hydroxy ethers, specifically methoxymethanol, ethoxymethanol, and 2-methoxyethanol.
View Article and Find Full Text PDFJ Phys Chem A
November 2024
Quantum Theory Project, Departments of Chemistry and Physics, University of Florida, Gainesville, Florida 32611, United States.
The thermal unimolecular decay of ethoxy is important in high-temperature combustion environments where the ethoxy radical is a key reactive intermediate. Two dissociation pathways of ethoxy, including the β-C-C scission to yield CH + CHO and the H-elimination to make H + CHCHO, were characterized using a high-level coupled-cluster-based composite quantum chemical method (mHEAT-345(Q)). The former route is found to be dominant while the latter is insignificant, in agreement with previous experimental and theoretical studies.
View Article and Find Full Text PDFPhys Chem Chem Phys
November 2024
Department of Chemistry, University of Hawai'i at Manoa, Honolulu, HI 96822, USA.
The merging of the electronic structure calculations and crossed beam experiments expose the reaction dynamics in the tin (Sn, P) - molecular oxygen (O, XΣ-g) system yielding tin monoxide (SnO, XΣ) along with ground state atomic oxygen O(P). The reaction can be initiated on the triplet and singlet surfaces addition of tin to the oxygen atom leading to linear, bent, and/or triangular reaction intermediates. On both the triplet and singlet surfaces, formation of the tin dioxide structure is required prior to unimolecular decomposition to SnO(XΣ) and O(P).
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