1,1,4,4-Tetramethyl-2-tetrazene (TMTZ) is considered as a prospective replacement for toxic hydrazines used in liquid rocket propulsion. The heat of formation of TMTZ was computed and measured, giving values well above those of the hydrazines commonly used in propulsion. This led to a predicted maximum I of 337 s for TMTZ/N O mixtures, which is a value comparable to that of monomethylhydrazine. We found that TMTZ has a vapor pressure well below that of liquid hydrazines, and it is far less toxic. Finally, an improved synthesis is proposed, which is compatible with existing industrial production facilities after minor changes. TMTZ is thus an attractive liquid propellant candidate, with a performance comparable to hydrazines but a lower vapor pressure and toxicity.

To optimize yields, the study of reaction kinetics related to the synthesis of 2-hydroxyethylhydrazine (HEH) obtained from the alkylation of N 2 H 4 by 2-chloroethanol (CletOH) was carried out with and without sodium hydroxide. In both cases, the main reaction of HEH formation was followed by a consecutive, parallel reaction of HEH alkylation (or dialkylation of N 2 H 4 ), leading to the formation of two isomers: 1,1-di(hydroxyethyl)hydrazine and 1,2-di(hydroxyethyl)hydrazine. In this study, hydrazine and hydroxyalkylhydrazine alkylations followed S N 2 reactions triggered directly by CletOH or indirectly in the presence of a strong base by ethylene oxide, an intermediate compound. The kinetics was studied in diluted mediums by quantifying HEH and CletOH by gas chromatography and gas chromatography coupled with mass spectrometry (GC-MS). The activation parameters of each reaction and the influence of a strong base present in the medium on the reaction mechanisms were established. A global mathematical treatment was applied for each alternative. It allowed modeling the reactions as a function of reagent concentrations and temperature. In the case of direct alkylation by CletOH, simulation was established for semi-batch and batch syntheses and was confirmed in experiments for concentrated mediums (1.0 M ≤ [CletOH] 0 ≤ 3.2 M and 15.7 M ≤ [N 2 H 4 ] 0 ≤ 18.8 M). Simulation therefore permits the prediction of the instantaneous concentration of reagents and products, in particular ethylene oxide concentration in the case of indirect alkylation, which must be as weak as possible.

This work deals with the synthesis, extraction, and purification of a new exocyclic hydrazine with cosmetic applications, N-aminopyrrolidine (NAPY). The final extraction and purification steps of the useful product are often linked to distillation operations. The optimization of these separation conditions requires then the knowledge of the thermodynamic properties of the liquid−vapor equilibria. The synthesis reactions are carried out by the Raschig process, which is based on the reaction of a large excess of amine with chloramine in aqueous medium and without any use of solvent. The distillation step involves the liquid−vapor equilibria in the ternary system NAPY + pyrrolidine + water and, first of all, requires the knowledge of the water + pyrrolidine binary system. For a better understanding of the behavior of aqueous mixtures of amine, three liquid− vapor binary diagrams of water + amine type were investigated by ebulliometry. The three binary isobaric diagrams water + pyrrolidine, water + butylamine, and water + diethylamine were established under atmospheric pressure. The evolution of the thermodynamic properties of these amines according to the nature of the substituent will be then deduced by comparison of these experimental diagrams. This study will thus lead us to a better understanding of the molecular interactions in the liquid phase.