Thermal Decomposition of 2-Methyltetrahydrofuran behind Reflected Shock Waves over the Temperature Range of 1179–1361 K

Rajakumar, B.; Arathala, Parandaman; Muthiah, Balaganesh

doi:10.1021/acs.jpca.0c11490

Cited by 3 publications

(3 citation statements)

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“… 11 The potential energy surface shows that 2-methyltetrahydrofuran-5-yl produces CO and n -butyl by ring-opening, H-transfer, and decarbonylation of the α-pentanal radical intermediate. Similar decarbonylation reactions were observed in decomposition of α-aldehyde radicals 28 and cyclic ether species, 29 , 30 and further evidenced in experiments of Rajakumar et al, 31 which indicated an unknown source of carbon monoxide during thermal decomposition of 2-methyltetrahydrofuran in a shock tube.…”

Section: Resultssupporting

confidence: 74%

“…12 The potential energy surface shows that 2methyltetrahydrofuran-5-yl produces CO and n-butyl by ringopening, H-transfer, and decarbonylation of the α-pentanal radical intermediate. Similar decarbonylation reactions were observed in decomposition of α-aldehyde radicals 29 and cyclic ether species, 30,31 and further evidenced in experiments of Rajakumar et al, 32 which indicated an unknown source of carbon monoxide during thermal decomposition of 2-methyltetrahydrofuran in a shock tube. Both unsaturated alkoxy radicals (1-pentene-4-oxy and 2pentene-4-oxy from R1 and R3 ring-opening, respectively) can undergo methyl loss via β-scission, yet over relatively higher barriers compared with other pathways.…”

Section: ■ Results and Discussionsupporting

confidence: 73%

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Unimolecular Reactions of 2,4-Dimethyloxetanyl Radicals

Doner¹,

Zádor

Rotavera³

2023

J. Phys. Chem. A

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Alkyl-substituted oxetanes are cyclic ethers formed via unimolecular reactions of QOOH radicals produced via a six-membered transition state in the preceding isomerization step of organic peroxy radicals, ROO. Owing to radical isomer-specific formation pathways, cyclic ethers are unambiguous proxies for inferring QOOH reaction rates. Therefore, accounting for subsequent oxidation of cyclic ethers is important in order to accurately determine rates for QOOH → products. Cyclic ethers can react via unimolecular reaction (ring-opening) or via bimolecular reaction with O 2 to form cyclic ether-peroxy adducts. The computations herein provide reaction mechanisms and theoretical rate coefficients for the former type in order to determine competing pathways for the cyclic ether radicals. Rate coefficients of unimolecular reactions of 2,4-dimethyloxetanyl radicals were computed using master equation modeling from 0.01 to 100 atm and from 300 to 1000 K. Coupled-cluster methods were utilized for stationary-point energy calculations, and uncertainties in the computed rate coefficients were accounted for using variation in barrier heights and in well depths. The potential energy surfaces reveal accessible channels to several species via crossover reactions, such as 2-methyltetrahydrofuran-5-yl and pentanonyl isomers. For the range of temperature over which 2,4-dimethyloxetane forms during n-pentane oxidation, the following are the major channels: 2,4dimethyloxetan-1-yl → acetaldehyde + allyl, 2,4-dimethyloxetan-2-yl → propene + acetyl, and 2,4-dimethyloxetan-3-yl → 3-butenal + methyl, or, 1-penten-3-yl-4-ol. Well-skipping reactions were significant in a number of channels and also exhibited a markedly different pressure dependence. The calculations show that rate coefficients for ring-opening are approximately an order of magnitude lower for the tertiary 2,4-dimethyloxetanyl radicals than for the primary and secondary 2,4-dimethyloxetanyl radicals. Unlike for reactions of the corresponding ROO radicals, however, unimolecular rate coefficients are independent of the stereochemistry. Moreover, rate coefficients of cyclic ether radical ring-opening are of the same order of magnitude as O 2 addition, underscoring the point that a competing network of reactions is necessary to include for accurate chemical kinetics modeling of species profiles for cyclic ethers.

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Section: Resultssupporting

confidence: 74%

Section: ■ Results and Discussionsupporting

confidence: 73%

Unimolecular Reactions of 2,4-Dimethyloxetanyl Radicals

Doner¹,

Zádor

Rotavera³

2023

J. Phys. Chem. A

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“…It is known that compounds with a larger HOMO-LUMO gap and chemical hardness are more resistant to undergoing chemical reactions or to being transformed by an external perturbation, such as an applied electric field. On the other hand, a low chemical softness value denotes a high tendency of the molecule to degrade, while a higher electronegativity reflects a higher tendency of the compound to form a bond [72,73]. The activation energy of the compounds was also evaluated, as the difference in the total energies of transitional and ground states.…”

Section: Methodsmentioning

confidence: 99%

Computational Studies of Energetic Property Peculiarities in Trinitrophenyl-Substituted Nitramines

Tamulienė

Šarlauskas

2023

Energies

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This research was performed using Becke’s three-parameter hybrid functional approach with non-local correlation provided by Lee, Yang, and Parr and the cc-pVTZ basis set. The geometry, total energy, and heat of formation of the most stable conformers of the nitramines under study were obtained to obtain the density, resistance to shock stimuli, detonation pressure, and velocity of the materials under study. The results obtained allow us to predict new multipurpose energetic materials with a good balance between energy and stability. Our findings show that N-(2-nitroethyl)-N-(2,4,6-trinitrophenyl)nitramine, N-(2,4,6-trinitrophenyl)-N-[(3,4,5-trinitro-1H-pyrazol-1-yl)methyl]nitramine, N-(2,2-dinitroethyl)-N-(2,4,6-trinitrophenyl)nitramine, N-(2,2,2-trinitroethyl)-N-(2,4,6-trinitrophenyl)nitramine, and N-(trinitromethyl)-N-(2,4,6-trinitrophenyl)nitramine possess better explosive properties and a greater stability compared to tetryl, although they remain sensitive to shock stimuli. Referring to the results obtained, we recommend new tetryl analogs containing dinitroethyl, trinitroethyl, and trinitromethyl substituents for practical usage.

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Polynitrobenzene Derivatives, Containing -CF3, -OCF3, and -O(CF2)nO- Functional Groups, as Candidates for Perspective Fluorinated High-Energy Materials: Theoretical Study

Tamuliene,

Sarlauskas

2024

Energies

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We performed a theoretical investigation of the fluorinated compounds’ morphology and stability. The research was conducted using the widely adopted DFT approach, specifically the B3LYP method and the cc-pVTZ basis set, aiming to design high-energy materials that exhibit low sensitivity, toxicity, instability, and reduced proneness to decomposition or degradation over a short period. In the paper, we presented the investigation results for the compounds whose total energy is the lowest. Their thermal and chemical stability was evaluated based on stability indicators such as cohesion, chemical hardness, and softness. The oxygen–fluorine balance is assessed to determine the sensitivity of these advanced materials. The density, detonation pressure, and velocity of the selected conformers were theoretically obtained to reveal the influence of -CF3, -OCF3, and cyclic -O(CF2)nO- fragments on the energetic properties of nitroaromatics as well as their stability and resistance to shock stimuli. The results enable the prediction of advanced energetic materials that achieve a favorable balance between power and stability. Based on the results achieved, we put forward CF3N2, OCF3N2, C2F6N2, 1CF2N2/O2CF2N2, and 2CF4N2/O2C2F4N2 for practical usage because these compounds possess greater stability compared to tetryl and better explosive properties than TNT.

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Thermal Decomposition of 2-Methyltetrahydrofuran behind Reflected Shock Waves over the Temperature Range of 1179–1361 K

Cited by 3 publications

References 72 publications

Unimolecular Reactions of 2,4-Dimethyloxetanyl Radicals

Unimolecular Reactions of 2,4-Dimethyloxetanyl Radicals

Computational Studies of Energetic Property Peculiarities in Trinitrophenyl-Substituted Nitramines

Polynitrobenzene Derivatives, Containing -CF3, -OCF3, and -O(CF2)nO- Functional Groups, as Candidates for Perspective Fluorinated High-Energy Materials: Theoretical Study

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