Energetic Properties of Rocket Propellants Evaluated through the Computational Determination of Heats of Formation of Nitrogen-Rich Compounds.

The 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.

Synthesis and characterization of secondary nitrosamines from secondary amines using sodium nitrite and p-toluenesulfonic acid.

We synthesized nitrosamines (R2N-NO) with R = iPr (1), nPr (2), nBu (3), and hydroxyethyl (4) from the amine using sodium nitrite/p-toluenesulfonic acid in CH2Cl2. The rate of formation of 1-4 increases in the direction iPr View Article and Find Full Text PDF

Energetic hydrazine-based salts with nitrogen-rich and oxidizing anions.

1,1,1-Trimethylhydrazinium iodide ([(CH(3))(3)N-NH(2)]I, 1) was reacted with a silver salt to form the corresponding nitrate ([(CH(3))(3)N-NH(2)][NO(3)], 2), perchlorate ([(CH(3))(3)N-NH(2)][ClO(4)], 3), azide ([(CH(3))(3)N-NH(2)][N(3)], 4), 5-amino-1H-tetrazolate ([(CH(3))(3)N-NH(2)][H(2)N-CN(4)], 5), and sulfate ([(CH(3))(3)N-NH(2)](2)[SO(4)]·2H(2)O, 6·2H(2)O) salts. The metathesis reaction of compound 6·2H(2)O with barium salts led to the formation of the corresponding picrate ([(CH(3))(3)N-NH(2)][(NO(2))(3)Ph-O], 7), dinitramide ([(CH(3))(3)N-NH(2)][N(NO(2))(2)], 8), 5-nitrotetrazolate ([(CH(3))(3)N-NH(2)][O(2)N-CN(4)], 9), and nitroformiate ([(CH(3))(3)N-NH(2)][C(NO(2))(3)], 10) salts. Compounds 1-10 were characterized by elemental analysis, mass spectrometry, infrared/Raman spectroscopy, and multinuclear NMR spectroscopy ((1)H, (13)C, and (15)N).

Synthesis, characterization, and energetic properties of salts of the 1-cyanomethyl-1,1-dimethylhydrazinium cation.

1,1-Dimethylhydrazine can be readily alkylated with bromoacetonitrile to form 1-cyanomethyl-1,1-dimethylhydrazinium bromide ([(CH(3))(2)N(CH(2)CN)NH(2)]Br, 1). The metathesis reaction of compound 1 led to the formation of a new family of energetic salts based on the [(CH(3))(2)N(CH(2)CN)NH(2)](+) cation and nitrate (2), perchlorate (3), azide (4), 5-aminotetrazolate ([H(2)N-CN(4)](-), 5), 5,5'-azobistetrazolate ([N(4)C-N=N-CN(4)](2-), 7), and picrate (8) anions. The new materials were characterized by elemental analysis, mass spectrometry, and (multinuclear) NMR and vibrational (infrared and Raman) spectroscopies.

Metal salts of the 4,5-dicyano-2H-1,2,3-triazole anion ([C4N5]-).

Diaminomaleodinitrile was reacted at low temperatures with in situ generated nitrous acid to form 4,5-dicyano-2H-1,2,3-triazole (1) in yields above 90%. Crystalline 1 was then reacted with one equivalent of a suitable alkali or alkaline earth metal base (typically a hydroxide or a carbonate) in a polar solvent to form the corresponding alkali and alkaline earth metal salts of 4,5-dicyano-2H-1,2,3-triazole (compounds 2-9). The thermal stability of the metal salts 2-9 was assessed by differential scanning calorimetry, which showed excellent thermal stabilities up to above 350 °C.

Energetic salts of the binary 5-cyanotetrazolate anion ([C2N5]-) with nitrogen-rich cations.

The reaction of cyanogen (NC-CN) with MN(3) (M=Na, K) in liquid SO(2) leads to the formation of the 5-cyanotetrazolate anion as the monohemihydrate sodium (1·1.5 H(2)O) and potassium (2) salts, respectively. Both 1·1.

Safe 5-nitrotetrazolate anion transfer reagents.

Silver 5-nitrotetrazolate (1) and copper(ii) 5-nitrotetrazolate 5-nitrotetrazole dihydrate (2) are useful reagents for the synthesis of 5-nitrotetrazole (NT) salts. Both compounds were synthesized and characterized by vibrational spectroscopy (IR and Raman) and differential scanning calorimetry (DSC). In addition, their sensitivity towards friction, shock and electrostatic discharge was tested by standard BAM methods.

Alkali and transition metal (Ag, Cu) salts of bridged 5-nitrotetrazole derivatives for energetic applications.

A family of energetic salts based on the novel 5-(5-nitrotetrazole-2-ylmethyl)-tetrazolate anion (NTTz(-)) with alkali metals (Li(+), Na(+), K(+), Rb(+) and Cs(+)) were synthesized by the reaction of the free acid 5-(5-nitrotetrazole-2-ylmethyl)-tetrazole with a suitable alkali metal base (bicarbonate or carbonate) in alcohol or water. The sodium salt () was, in turn, used to form salts containing the NTTz(-) anion and Ag(+) () or Cu(2+) (, and ) cations. The new compounds were characterized by IR, Raman and NMR spectroscopy, mass spectroscopy, elemental analysis and differential scanning calorimetry (DSC).

Energetic silver salts with 5-aminotetrazole ligands.

Methylation of 5-amino-1H-tetrazole (1) gives 1-methyl-5-amino-1H-tetrazole (2) and 2-methyl-5-amino-1H-tetrazole (3). A new family of energetic silver complexes based on ligands 1, 2 and 3 with perchlorate and nitrate anions (10-15) were synthesized and characterized by using IR, Raman, and NMR ((1)H, (13)C, (14)N, and (35)Cl NMR) spectroscopy, elemental analysis, and mass spectrometry. The crystal structures of the compounds were determined where possible and reveal interesting structural details that are discussed herein.

Alkali metal 5-nitrotetrazolate salts: prospective replacements for service lead(II) azide in explosive initiators.

A family of sensitive energetic salts of the 5-nitrotetrazolate anion with alkali metal cations (Li+, Na+, K+, Rb+ and Cs+) were synthesized either by the digestion of an acid copper salt of 5-nitrotetrazole with a suitable metal hydroxide, or alternatively by reaction of ammonium 5-nitrotetrazolate with a suitable metal base (MOH, MHCO3 or M2CO3) in aqueous or alcoholic solution. All the compounds were characterized by analytical methods (elemental analysis and mass spectrometry) and spectroscopic methods (NMR and vibrational spectroscopy). The lighter metal salts and , incorporate three and two crystal water molecules in the structure, respectively, whereas the heavier alkali metal derivatives form anhydrous species, and thus showed enhanced sensitivity to friction and shock.

Simple, nitrogen-rich, energetic salts of 5-nitrotetrazole.

A new family (ammonium, 1, hydrazinium, 2, guanidinium, 3, aminoguanidinium, 4, diamino-guanidinium, 5, and triaminoguanidinium, 6) of simple, nitrogen-rich energetic salts based on 5-nitro-2 H-tetrazole (HNT) were synthesized. In addition, the hemihydrate of 1 (1a) and the hydrate of 6 (6a) were also isolated. In all cases, stable salts were obtained and fully characterized by vibrational (IR, Raman) spectroscopy, multinuclear ((1)H, (13)C and (14)N) NMR spectroscopy, mass spectrometry, elemental analysis, and X-ray structure determination.

1,2,4-triazolium-cation-based energetic salts.

3,4,5-Triamino-1,2,4-triazole (guanazine, 1) can be readily methylated with methyl iodide yielding methylguanazinium iodide (2). Salts containing the novel methylguanazinium cation with energetic anions were synthesised by metathesis reactions with silver azide (3), silver nitrate (4), silver perchlorate (5), sodium 5,5'-azotetrazolate (6), silver 5-nitrotetrazolate (7) and silver dinitramide (8), yielding a new family of heterocycle-based salts, which were fully characterised by analytical (mass spectrometry and elemental analysis) and spectroscopic methods (IR, Raman and NMR). In addition, the molecular structures of all compounds were confirmed by X-ray analysis, revealing extensive hydrogen-bonding in the solid state and densities between 1.

Salts of methylated 5-aminotetrazoles with energetic anions.

1-methyl-5-aminotetrazole (4, MAT) can easily be protonated by strong acids, yielding known but largely uninvestigated 1-methyl-5-aminotetrazolium nitrate (4a) and perchlorate (4b). Methylation, rather than protonation, of 4 with iodomethane followed by the exchange of the iodide (5a) for nitrate (5b), perchlorate (5c), azide (5d), and dinitramide (5e) yields a new family of energetic methylated aminotetrazole salts. In all cases, stable salts were obtained and fully characterized by vibrational (IR, Raman) spectroscopy, multinuclear NMR spectroscopy, mass spectrometry, elemental analysis, and X-ray structure determination.