The Pyridazine Scaffold as a Building Block for Energetic Materials: Synthesis,Characterization, and Properties

In the present studies, the synthesis of new energetic materials based on the pyridazine scaffold and their characterization is the main subject. For this purpose, desired 3,5‐dimethoxy‐4,6‐dinitropyridazine‐1‐oxide ( 7 ) was synthesized in the first instance. The persubstituted pyridazine precursor laid the groundwork for further preparative modification. The targeted functionalization through the regioselective introduction of various smaller amine nucleophiles such as methylamine or 2‐aminoethanol gave several new energetic materials. Among them are 3,5‐bis(methylamino)‐4,6‐dinitropyridazine‐1‐oxide ( 8 ), 3,5‐bis(methylnitramino)‐4,6‐dinitropyridazine‐1‐oxide ( 9 ), 3,5‐bis(dimethylamino)‐4,6‐dinitropyridazine‐1‐oxide ( 10 ), and 3,5‐bis((2‐hydroxyethyl)amino)‐4,6‐dinitropyridazine‐1‐oxide ( 11 ). With the aim of increasing the detonation performance, compound 8 was additionally nitrated and 3,5‐bis(methylnitramino)‐4,6‐dinitropyridazine‐1‐oxide ( 9 ) was obtained. These new energetic materials were characterized and identified by multinuclear NMR (¹H, ¹³C, ¹⁴N, ¹⁵N) and IR spectroscopy, elemental analysis and mass spectrometry. In addition, their sensitivities toward impact, friction and electrostatic discharge were thoroughly examined. Furthermore, obtained single‐crystals of the substances were characterized by low‐temperature single‐crystal X‐ray diffraction.     

Specific thermal and thermodynamic properties of the tellurites Fe2(TeO3)3, Fe2TeO5 and Fe2Te4O11

The temperature dependence of the molar heat capacities of the tellurites Fe₂(TeO₃)₃, Fe₂TeO₅ and Fe₂Te₄O₁₁ were determined. By statistical manipulation of the values obtained, the parameters in the equations for the corresponding compounds showing this dependence were determined using the least-squares method. These equations together with the standard molar entropies were used to determine the thermodynamic functions Δ₀^T S _m⁰, Δ_T^T,H _m⁰ and (Φ_m⁰ + Δ₀^T’ H _m⁰ / T) for T’=298.15 K.     

Tribochemical Synthesis of Magnesium Zirconate for Some Specific Purposes

MgZrO₃ was synthesized by tribochemical and thermal treating of a mixture of MgO and ZrO₂ corresponding to its stoichiometry. The gained compound is identified by chemical and X-ray analysis.     

Das Löslichkeitsdiagramm des Systems ZnSeO4?H2SeO4?H2O und einige Eigenschaften der erhaltenen Verbindungen

Isotherms of Solubility in the System ZnSeO₄? H₂SeO₄? H₂O and Some Properties of the Compounds Obtained The isotherms of solubility in the system ZnSeO₄? H₂SeO₄? H₂O were studied at 25 and 100°C. Some properties of the compounds obtained were investigated.     

Study on the kinetics of isothermal decomposition of selenites from IVB group of the periodic system

The thermal stability and kinetics of isothermal decomposition of the selenites of germanium, tin and lead was studied. A dependence between the process activation energy and the radius and electron polarizability of the cations was observed. It was explained with the different degree of the effect of counterpolarization of the selenite anion. The negative value of the change of entropy of activation showed that the active complex is more complicated formation than the reagent. The higher absolute value of the change of entropy measured for the formation of the active complex Ge(SeO₃)₂ compared to that for Sn(SeO₃)₂ shows that the degree of rearrangement (necessary changes) of the initial crystalline structure increases with the decrease of cation radius. The isothermal decomposition of the selenites from IVB group of the periodic system was considered to be ‘slow’ reaction due to the significantly lower than unity values of the steric factor.     

Chemistry of the Thermal Decomposition of Lutetium Selenities

Summary.  The solubility isotherm of the system Lu₂O₃–SeO₂–H₂O was studied at 100°C. The compounds of the three-component system were identified by Schreinemakers’ method and chemical, derivatograph and X-ray phase analyses after separation in the pure state: Lu₂(SeO₃)₃·4H₂O and LuH(SeO₃)₂·2H₂O. Received February 27, 2002; accepted (revised) April 26, 2002     

Über den Mechanismus der mechanochemischen Synthese anorganischer Verbindungen

In the present paper some data on phenomena observed during the mechanochemical synthesis of metal chalcogenides are given. The explosive-like character of the synthesis as a result of continual accumulation of energy in the crystal lattice of the substances submitted to mechanical dispersion is described for the first time. The influence of different factors on the time until explosion takes place is investigated.     

Molar heat capacities of the tellurites CoTeO3, MnTeO3 and MnTe6O13 in medium temperature range

The temperature dependence of the molar heat capacities of the tellurites CoTeO₃, MnTeO₃ and MnTe₆O₁₃ are determined. By statistical manipulation of the values obtained, the parameters in the equations for the corresponding compounds showing this dependence are determined using the least-squares method. These equations and the standard molar entropies are used to determine the thermodynamic functions for T'=298.15 K.     

Löslichkeitsisotherme und Phasendiagramm des Systems Tm2O3-SeO2-H2O bei 100°C

Summary.  The selenites of thulium are used as starting substances to obtain the respective selenides which have valuable semiconductive properties. In analogy to the tellurites of the rare-earth elements, they can be applied as materials for the production of lasers. Bearing in mind the various recent usages of the lanthanides’ selenites (thulium in particular), the preparation and study of thulium selenites is considered to be a question of present interest. Therefore, a physico-chemical study of the system Tm₂O₃-SeO₂-H₂O at 100°C has been carried out.

Received December 19, 2000. Accepted (revised) April 10, 2001     

The Diagnostic Probing of Laser Plasma with a Femtosecond Time Resolution Using a Three-Channel Polarization Interferometer

Physics of Atomic Nuclei - The possibility of modifying the scheme of the previously developed three-channel polarization interferometer and creating a device that allows laser probing of plasma...