Thermal stability of energetic 6,8-dinitrotriazolo[1,5-a]pyridines: Interplay of thermal analysis and quantitative quantum chemical calculations

Melnikov, Igor N.; Kiselev, Vitaly G.; Bastrakov, Maxim A.; Далингер, И. Л.; Пивкина, Алла Н.

doi:10.1016/j.tca.2022.179342

Cited by 1 publication

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“…Therefore, the introduction of the amino group to the benzotriazole moiety increases its thermal stability. This fact is in line with our previous results for dinitrotriazolopyridines 3 and 4 [ 21 ].…”

Section: Resultssupporting

confidence: 94%

“…This effect can introduce inaccuracies in determining the total heat effect and subsequent thermokinetic modeling. It is worth mentioning that DBT exhibits very similar thermal behavior to its structural analog, 6,8-dinitrotriazolopyridine ( 3 ) [ 21 ]. The decomposition heat effect and residual sample mass dependences on the heating rate can be found in the Supporting Information (Figure S1) .…”

Section: Resultsmentioning

confidence: 99%

“…In order to obtain a deeper insight into the possible decomposition mechanisms of dinitrobenzotriazoles, we also considered the structurally similar dinitrotriazolopyridines 3 and 4 , and simpler species with the dinitrobenzotriazoles skeleton, viz., 1,3-nitrobenzene ( 5 ) and 1,2,3-triazole ( 6 , Figure 1 ). Recently, we have studied the thermal stability of the similar compounds 3 and 4 using pressure DSC and quantum chemical calculations at the DLPNO-CCSD(T) level [ 21 ]. We found that the thermolysis of 3 occurs in the melt and is described by a kinetic scheme with two autocatalytic independent parallel reactions, whereas the decomposition kinetics of 4 is more complex due to its overlap with the melting.…”

Section: Introductionmentioning

confidence: 99%

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Thermochemistry, Tautomerism, and Thermal Stability of 5,7-Dinitrobenzotriazoles

Melnikov

Kiselev

Далингер

et al. 2023

IJMS

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Nitro derivatives of benzotriazoles are safe energetic materials with remarkable thermal stability. In the present study, we report on the kinetics and mechanism of thermal decomposition for 5,7-dinitrobenzotriazole (DBT) and 4-amino-5,7-dinitrobenzotriazole (ADBT). The pressure differential scanning calorimetry was employed to study the decomposition kinetics of DBT experimentally because the measurements under atmospheric pressure are disturbed by competing evaporation. The thermolysis of DBT in the melt is described by a kinetic scheme with two global reactions. The first stage is a strong autocatalytic process that includes the first-order reaction (Ea1I = 173.9 ± 0.9 kJ mol−1, log(A1I/s−1) = 12.82 ± 0.09) and the catalytic reaction of the second order with Ea2I = 136.5 ± 0.8 kJ mol−1, log(A2I/s−1) = 11.04 ± 0.07. The experimental study was complemented by predictive quantum chemical calculations (DLPNO-CCSD(T)). The calculations reveal that the 1H tautomer is the most energetically preferable form for both DBT and ADBT. Theory suggests the same decomposition mechanisms for DBT and ADBT, with the most favorable channels being nitro-nitrite isomerization and C–NO2 bond cleavage. The former channel has lower activation barriers (267 and 276 kJ mol−1 for DBT and ADBT, respectively) and dominates at lower temperatures. At the same time, due to the higher preexponential factor, the radical bond cleavage, with reaction enthalpies of 298 and 320 kJ mol−1, dominates in the experimental temperature range for both DBT and ADBT. In line with the theoretical predictions of C–NO2 bond energies, ADBT is more thermally stable than DBT. We also determined a reliable and mutually consistent set of thermochemical values for DBT and ADBT by combining the theoretically calculated (W1-F12 multilevel procedure) gas-phase enthalpies of formation and experimentally measured sublimation enthalpies.

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Section: Resultssupporting

confidence: 94%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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