Influence of the structure of N-amino derivatives of dinitropyrazoles on their combustion mechanism and thermal stability

Influence of the structure of N-amino derivatives of dinitropyrazoles on their combustion mechanism and thermal stability Full article

Journal

Combustion and Flame
ISSN: 1556-2921 , E-ISSN: 0010-2180

Output data

Year: 2026, Volume: 283, Article number : 114584, Pages count : DOI: 10.1016/j.combustflame.2025.114584

Authors

Sinditskii Valery P. ¹ , Smirnov Sergey P. ¹ , Smirnova Anastasia D. ¹ , Filatov Sergey A. ¹ , Singh Vladimir N. ¹ , Yudin Nikolay V. ¹ , Vatsadze Irina A. ² , Shkineva Tatyana K. ² , Dalinger Igor L. ²

Affiliations

1	Mendeleev University of Chemical Technology, 125047, 9 Miusskaya sq., Moscow, Russia
2	Zelinsky Institute of Organic Chemistry, Russian Academy of Science, Moscow, Leninsky Pros., 47, Russia

Studies of N-amino pyrazole derivatives combustion revealed that introducing an N-amino group into dinitropyrazole molecules not only alters physicochemical properties (melting point, density, and thermal stability) but also significantly affects combustion behavior. The 3,4-dinitro derivatives, 1-amino-3,4-dinitropyrazole (1,3,4-ADNP) and 1,5-diamino-3,4-dinitropyrazole (1,5,3,4-DADNP), exhibit pressure-dependent burning rate curves with distinct pressure ranges where combustion fails to propagate under standard ignition conditions. In contrast, their structural isomer with different nitro group positioning (1,3,5-ADNP) demonstrated sustained combustion across the entire investigated pressure range. Thermal stability analysis demonstrated that the decomposition of both 3,4-dinitro derivatives is accompanied by significant autocatalysis. The autocatalytic agent was identified as the N-imino radical of dinitropyrazoles, which reacts not only with NO2 radicals but also with nitro groups in parent molecules. Thermocouple measurements of combustion waves in N- aminodinitropyrazoles revealed that at similar surface (boiling) temperatures, the more pronounced autocatalysis in 3,4-dinitro derivatives accounts for their greater decomposition depth in the melt phase. This determines their combustion mechanism, which is dominated by the condensed phase. The 3,5-isomer shows less than 5 % melt-phase decomposition, resulting in gas-phase controlled combustion. The observed combustion instability of 1,3,4-ADNP and 1,5,3,4-DADNP arises from the transition between the two dominant reaction zones: condensed-phase and gas-phase controlled combustion regimes.

Sinditskii V.P. , Smirnov S.P. , Smirnova A.D. , Filatov S.A. , Singh V.N. , Yudin N.V. , Vatsadze I.A. , Shkineva T.K. , Dalinger I.L.
Influence of the structure of N-amino derivatives of dinitropyrazoles on their combustion mechanism and thermal stability
Combustion and Flame. 2026. V.283. 114584 . DOI: 10.1016/j.combustflame.2025.114584 WOS Scopus OpenAlex

Submitted:	Sep 1, 2025
Published online:	Oct 28, 2025

≡ Web of science:	WOS:001615177600002
≡ Scopus:	2-s2.0-105019949241
≡ OpenAlex:	W4415606420