Vacuum pyrolysis of nitrostyrenes

Kinstle, Thomas H.; Stam, J. G.

doi:10.1021/jo00831a011

Cited by 27 publications

(11 citation statements)

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“…(17) and (19) are shown in These two decomposition pathways are virtually equivalent energetically. As already noted, aldehydes and nitriles were detected as major products of pyrolysis of b-nitrostyrenes [28].…”

Section: ääääääääääääsupporting

confidence: 65%

“…This pathway was suggested for the first time by Kinstle and Stam [28] as applied to high-temperature pyrolysis of b-nitrostyrenes:…”

Section: Radical Decompositionmentioning

confidence: 99%

“…10) can decompose by two pathways (Scheme 4, with the relative energies given at structures and reaction barriers, at arrows; values in kJ mol !1 ). The first pathway involves isomerization (28) into compound XX with the half-chair conformation, followed by formation of a five-membered ring [XXII, reaction (30)], nitro3nitrite rearrangement [XXIII, reaction (31)], and elimination of HNO 2 [reaction (32)]. The second pathway via biradical XXI is more energetically favorable according to the available data.…”

Section: ääääääääääääääääääääääääáääääääääääääääääáäääääääääääääääáäämentioning

confidence: 99%

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Mechanism of gas-phase decomposition of nitroethylene: A theoretical study

2004

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Calculations by the B3LYP density functional method with various basis sets and by the QCISD(T)/6-31G(d) ab initio method showed that the main pathway of monomolecular gas-phase decomposition of nitroethylene is that involving a cyclic intermediate, 4H-1,2-oxazete 2-oxide; the barrier of its formation (201.9, 203.9, and 216.5 kJ mol !1 , as estimated by various methods) reasonably agrees with the experimental value (191.9 kJ mol !1 ). The barriers of alternative pathways of gas-phase decomposition of nitroethylene are considerably higher. The barriers of reactions involving radical cations are considerably lower than those of the similar reactions involving molecules. Among all the considered pathways of nitroethylene decomposition, bimolecular pathways are the most favorable energetically.Two major pathways of gas-phase decomposition of aliphatic nitro compounds have been proved experimentally: homolytic cleavage of the C3N bond with generation of free radicals and elimination of HNO 2 [13 4]. The molecular mechanism is realized at relatively low temperatures (up to 350oC) with mononitroalkanes containing a hydrogen atom in the a position relative to the nitro group, and also with halonitroalkanes RCH 2 CHXNO 2 (X = Hlg) [2, 3]. Gasphase decomposition of nitroethylene I and other a-nitroolefins is presumed to occur by a similar mechanism [2, 3, 5]. For mononitroalkanes, the molecular mechanism of HNO 2 elimination is confirmed by data on the composition of products in the initial steps of decomposition [1,2] and by the results of quantumchemical calculations [6 38]. Data on the composition of products formed in the initial steps of decomposition of I are lacking; therefore, the molecular mechanism for this compound is just a hypothesis. Published results of quantum-chemical studies of nitroethylene decomposition [9,10] are apparently insufficient to make any definite conclusions on the primary step of the monomolecular gas-phase decomposition or to cast doubt on the suggested pathway of HNO 2 elimination. In [11,12], we found that the barrier to elimination of HNO 2 from a molecule of I [223.9 kJ mol !1 according to B3LYP/6-311++G(df,p) calculations] significantly exceeds the experimental activation energy of the gas-phase decomposition (191.9 kJ mol !1 ).In this work, we studied theoretically various alternative pathways of monomolecular decomposition of

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Section: ääääääääääääsupporting

confidence: 65%

“…This pathway was suggested for the first time by Kinstle and Stam [28] as applied to high-temperature pyrolysis of b-nitrostyrenes:…”

Section: Radical Decompositionmentioning

confidence: 99%

Section: ääääääääääääääääääääääääáääääääääääääääääáäääääääääääääääáäämentioning

confidence: 99%

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Mechanism of gas-phase decomposition of nitroethylene: A theoretical study

2004

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“…This stepwise reaction was found to be highly exothermic with the heat release of 34.9 kcal/mol. The decomposition mechanism through a formation of the 1,2-oxazete 2-oxide structure, initially proposed for high-temperature pyrolysis of β-nitrostyrenes, 58 has been recently reported for nitroalkenes 59 and DADNE. 60 The oxygen transfer (DM6 path, Figure 3), another type of isomerization, results in the formation of nitroso-furoxan isomers of BNFF and, similarly to the ANFF-1 and BNFF-1 molecules, 57 exhibits significantly higher activation barriers (70−80 kcal/mol, Table 4) than the corresponding homolytic cleavage of the C−NO 2 bonds and the CONO-isomerization reactions.…”

Section: Introductionmentioning

confidence: 96%

Searching for Low-Sensitivity Cast-Melt High-Energy-Density Materials: Synthesis, Characterization, and Decomposition Kinetics of 3,4-Bis(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole-2-oxide

et al. 2015

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The most comprehensive approach to analyze and characterize energetic materials is suggested and applied to enable rational, rigorous design of novel materials and targeted improvements of existing materials to achieve desired properties. We report synthesis, characterization of the structure and sensitivity, and modeling of thermal and electronic stability of the energetic, heterocyclic compound, 3,4-bis(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole-2-oxide (BNFF). The proposed novel, relatively simple synthesis of BNFF in excellent yields allows for an efficient scale up. Performing careful characterization indicates that these materials offer an unusual combination of properties and exhibit a relatively high energy density, high and controllable stability against decomposition, low melting temperature, and low sensitivity to initiation of detonation. First-principles calculations of activation barriers and reaction rate constants reveal the decomposition scenarios that govern the thermal stability and chemical behavior of BNFF, which appreciably differ from conventional nitro compounds. Details of the electronic structure and calculated electronic properties suggest that BNFF is an excellent candidate energetic material on its own and an attractive ingredient of modern energetic formulations to improve their stability and enable highly controllable chemical decomposition.

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“…Cyclic nitronates are an important class of compounds because they pose useful intermediates in the synthesis of complex nitrogen-containing scaffolds due to their high reactivity as 1,3-dipoles and availability from nitroalkenes [ 1 , 2 , 3 , 4 ]. The main methods of obtaining cyclic four-membered nitronates are thermal and photochemical methods involving the cleavage of unsaturated nitro compounds [ 5 , 6 , 7 , 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

The Molecular Mechanism of the Formation of Four-Membered Cyclic Nitronates and Their Retro (3 + 2) Cycloaddition: A DFT Mechanistic Study

Kącka‐Zych

2021

Molecules

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In the present work, the formation of the four-membered cyclic nitronates and the retro (3 + 2) cycloaddition (retro-32CA) reaction of the 4H-[1,2]oxazete 2-oxide were studied using the density functional theory method at the MPWB1K/6-311G(d,p) theoretical level. The electronic structure of 3-tert-butyl-4,4-dimethyl-1,2-dinitro-pent-2-ene was known through electron localization function analysis, natural population analysis, and molecular electrostatic potential analysis. The formation of 4,4-di-tert-butyl-3-nitromethyl-4H-[1,2]oxazete 2-oxide proceeds through a one-step mechanism. The mechanism of the retro-32CA leading to di-tert-butyl ketone and nitrile oxide derivative should be described as an asynchronous two-stage one-step process. The bonding evolution theory study was carried out to clarify the mechanisms of the formation of 4H-[1,2]oxazete 2-oxide and their retro-32CA.

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Vacuum pyrolysis of nitrostyrenes

Cited by 27 publications

References 3 publications

Mechanism of gas-phase decomposition of nitroethylene: A theoretical study

Mechanism of gas-phase decomposition of nitroethylene: A theoretical study

Searching for Low-Sensitivity Cast-Melt High-Energy-Density Materials: Synthesis, Characterization, and Decomposition Kinetics of 3,4-Bis(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole-2-oxide

The Molecular Mechanism of the Formation of Four-Membered Cyclic Nitronates and Their Retro (3 + 2) Cycloaddition: A DFT Mechanistic Study

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