Syntheses, Characterizations And Thermoanalyses Of 3,5-dinitro-hydroxylpyridine Energetic Catalysts

With the development of our country's spaceflight and the promotingneeds of high-technology arms in national defense area, the research for high-propertypropellants are hot-spot currently. Buming-rate catalysts are the indispensablecomponent for solid propellants in order to adjust and improve their trajectoryproperties, and also the very important energetic material in the propellant. Researchfor good burning-rate catalysts is the main direction to improving properties withoutchanging the major components of the propellants. In the first part of this dissertation,the ingredients, functions, species and their applications of burning-rate catalysts arebriefly summarized and energetic catalysts derived from 3,5-dinitropyridone arereviewed concisely.In the second part of this dissertation, three 3,5-dinitropyridone ligands weresynthesized and were characterized by Elemental Analysis, FT-IR and thermoanalysis.Single crystals of the compounds 2-hydroxy-3,5-dinitropyridine(1) and 4-hydroxy-3,5-dinitropyridine-N-oxide(3), suitable for X-ray diffraction analysis, were grown andtheir structures were determined. The powder XRD profile of 1 indicated that thevalues of diffraction peaks of the polycrystalline sample are in good agreement withthe results simulated on the basis of single-crystal structure, which proves the phasepurity of the powder product.In the third part, eighteen energetic complexes were synthesized with the threeligands and alkali metals and alkaline earth metal compounds. These resultingcomplexes were also undergone Elemental analysis, FT-IR and TG-DSC analysis. Thecrystal structures of eleven complexes were determined by single-crystal X-raydiffraction analysis. The structures revealed that sodium 3,5-dinitropyrid-4-onate(14)molecule contains two water molecules and that the anions link the Na⁺ ions, each ofwhich is coordinated by four water molecules, into a linear chain that runs along the caxis of the unit cell. The crystal structures of the heavy alkali-metal complexesrevealed that the cation atom is eight-coordinate in both rubidium3,5-dinitropyrid-2-onate(7) and cesium 3,5-dinitropyrid-2-onate(8), with a crystalwater in 8; rubidium 3,5-dinitropyrid-4-onate(16) and cesium 3,5-dinitropyrid-2-onate(17) are very similar in structure and the parallelogram M₂O₂ units, consisting of two metal atoms and two bridging oxygen atoms, extend along the c axis. Neutralligands and anion ligands coordinate with cations in rubidium 3,5-dinitro-4-pyridone-N-hydroxylate(21). In the self-assembly of the cesium 3,5-dinitro-4-pyridone-N-hydroxylate(22) configuration, the versatile oxygen bridges act important roles, alongthe b axis; the two oxygen-bridges and the four oxygen-bridges appear alternativelybetween the adjacent cesium cations which results in a corrugated chain, aromaticÏ€-Ï€-stacking was also found in this compound. In the magnesium3,5-dinitropyrid-2-onate(9) and magnesium 3,5-dinitropyrid-4-onate(18), the cationsand anions are linked by static interactions with each cation being coordinated with sixwater molecules. Both barium 3,5-dinitropyrid-2-onate(12) and barium3,5-dinitropyrid-4-onate(19) are consisting of oxygen-bridged dimeric units. Thethermoanalysis results clearly indicated that they are blunt compounds as thedecomposition tempreture are higher than 200℃. The powder XRD analyses ofcompounds 7, 9, 16 and 17 revealed that the four powder products are of high purity.In the fourth part, ten energetic complexes were synthesized utlizing the acidproperty of ligands to react with a few transition-metal carbonates. These compoundswere also undergone Elemental analysis and FT-IR charactgerization. The crystalstructures of two complexes were determined by X-ray diffraction analysis. Incompound lead 3,5-dinitropyrid-2-onate(27), the arrangement of the ligands suggests agap or hole in the coordination geometry around the metal ion and the coordinationsphere around the lead atoms is hemidirected with a significant gap trans to thechelating ligands. Beacause of the existence of water molecules and the N-H…O systemin compound copper 3,5-dinitro-4-pyridone-N-hydroxylate(31), abundant hydrogenbonds are found in it.In this paper, a series of 3,5-dinitro-hydroxy-pyridine energetic complexes weresynthesized and characterized by physicochemical methods, which enriched data forseeking better energetic catalysts. Also, the molecular structures of most part of thecompounds are determined which will provide support based on the viewpoint ofmolecular level for the catalytic machanisms of these type of compounds.