Measurements of isobaric VLL equilibria of the 1,1,4,4-tetramethyl-2-tetrazene-water binary system: novel experimental approach and modeling essays

International audienc

Study of the reactivity of 1,1’-dimethylbistetrazole towards catalytic hydrogenation and chemical reduction

International audienceInvestigating the possibility of a straightforward formation of tetrazoline or tetrazolidine structures, the reactivity of a tetrazole derivative towards reducing conditions has been studied. The catalytic hydrogenation of 1,1’-dimethylbistetrazole (DMBT) was carried out using various catalysts (Pd/C, Pt/C, Rh/C, Pd/Pt/C, Lindlar, PtO2 and Raney Ni) over a wide range of hydrogen pressure (35–150 bar) and a temperature range from 20 to 60 °C. This exhaustive study enabled to find the optimal conditions for DMBT hydrogenation and to suggest a plausible reaction mechanism. The chemical reduction of DMBT was conducted using several hydrides (BH3, NaBH4, DIBAL and LiAlH4). The reduction products were identified subsequently to conditions optimizing. The suggested reaction mechanism, featuring a retro-[3 + 2]-cycloaddition, was validated by both experimental and theoretical approaches

Energetic Nitrogen‐Rich Polymers with a Tetrazene‐Based Backbone

International audienceNew energetic polymers were synthesized from monomers featuring the trans-2-tetrazene unit. In contrast to traditional binders, such as the inert hydroxytelechelic polybutadiene or the glycidyl azide polymers-where the energetic features are on the side chains-, the energetic groups in the polytetrazenes are incorporated directly in the polymer backbone. Thermal analyses evidenced that decomposition occurs at ~130 °C, regardless of the polymer structure. Glass transition temperatures range from-34.2 to 0.2°C, and they could be lowered further (to-61°C) with the help of a new diazido tetrazene energetic plasticizer. Interestingly, hexafluoro isopropanol (HFIP) enables a complete, room temperature depolymerization within one week. This should enable the recycling of the unused pyrotechnic compositions based on these new binders

Solvent-free synthesis and properties of functionalized hydrazines and bishydrazines as energetic ingredients for propulsion applications

International audienc

Energetic properties of rocket propellants evaluated through the computational determination of heats of formation of nitrogen-rich compounds

International audienceThe use of ab initio and DFT methods to calculate the enthalpies of formation of solid ionic compounds is described. The results obtained from the calculations are then compared with those from experimental measurements on nitrogen-rich salts of the 2,2-dimethyltriazanium cation (DMTZ) synthesized in our laboratory and on other nitrogen-rich ionic compounds. The importance of calculating accurate volumes and lattice enthalpies for the determination of heats of formation is also discussed. Furthermore, the crystal structure and hydrogen-bonding networks of the nitroformate salt of the DMTZ cation is described in detail. Lastly, the theoretical heats of formation were used to calculate the specific impulses (I-sp) of the salts of the DMTZ cation in view of a prospective application in propellant formulations