This project was directed towards the further development of the Savannah River National Laboratory (SRNL) lab-scale electrochemical synthesis of the hydrogen storage material alpha-alane and Ardica Technologies-SRI International (SRI) chemical downstream processes that are necessary to meet DoE cost metrics and transition alpha-alane synthesis to an industrial scale. Ardica has demonstrated the use of alpha-alane in a fuel-cell system for the U.S. Army WFC20 20W soldier power system that has successfully passed initial field trials with individual soldiers. While alpha-alane has been clearly identified as a desirable hydrogen storage material, cost-effective means for its production and regeneration on a scale of use applicable to the industry have yet to be established. We focused on three, principal development areas: 1. The construction of a comprehensive engineering techno-economic model to establish the production costs of alpha-alane by both electrochemical and chemical routes at scale. 2. The identification of critical, cost-saving design elements of the electrochemical cell and the quantification of the product yields of the primary electrochemical process. A moving particle-bed reactor design was constructed and operated. 3. The experimental quantification of the product yields of candidate downstream chemical processes necessary to produce alpha-alane to complete the most cost-effective overall manufacturing process. Our techno-economic model shows that under key assumptions most 2015 and 2020 DOE hydrogen storage system cost targets for low and medium power can be achieved using the electrochemical alane synthesis process. To meet the most aggressive 2020 storage system cost target, $1/g, our model indicates that 420 metric tons per year (MT/y) production of alpha-alane is required. Laboratory-scale experimental work demonstrated that the yields of two of the three critical component steps within the overall “electrochemical process” were sufficiently high to meet this production target. In the case of the yield of the third step, the crystallization of alpha-alane from the primary alane-related product of the electrochemical reaction, further development is required.

The eight coordinate complexes of 1,2-bis(dimethylarsino)benzene, MCl4(diars)2 where M is Th or U, and 1,2-bis(dimethylphosphino)benzene, UCl4(diphos)2, are prepared and characterized. Both coordination complexes of uranium crystallize in the tetragonal crystal system in space group I4¯2m, in which the geometry is a D2d-dodecahedron. In solution the uranium complexes do not exchange with added free ligand on the NMR time scale but they undergo bidentate ligand exchange on the chemical time scale. The 31P{1H} NMR chemical shifts of UI4(diphos)2 and UX4(dmpe)2, X = Cl, Br, I range from 1500 to 2100 ppm and are strongly dependent on temperature.

This study presents the synthesis and characterization of a fused, tricyclic 1,2,3,4-tetrazine ring system. The molecule is synthesized in a three-step process from 5,5'-dinitro-bis,1,2,4-triazole via a di-N-amino compound. Oxidation to form the azo-coupled fused tricyclic 1,2,3,4-tetrazine is achieved using tert-butyl hypochlorite as the oxidant. The di-N-amino compound and the desired fused tricyclic 1,2,3,4-triazine display interesting thermal behavior and are predicted to be high-performance energetic materials.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Ein energetischer kondensierter Heterocyclus wurde in zwei Stufen synthetisiert, wie von D. E. Chavez et al. in der Zuschrift auf S. 13165 ff. beschrieben. Erst liefert eine doppelte N-Aminierung des Bis(tetraethylammonium)-Salzes von 3,3′-Dinitro-5,5′-bi(1,2,4-triazol) ein thermisch stabiles energetisches Material, das gegen Schlag, Funken und Reibung unempfindlich ist. Eine Azokupplung schließt dann den 1,2,3,4-Tetrazin-Ring unter Bildung eines tricyclischen Systems mit hoher Energiedichte und ausgezeichneten Explosionseigenschaften.

The fluoronitramide anion, as its potassium, tetraisopropyl p-phenylenediguanidinium, and tetraphenylphosphonium salts, have been synthesized. The latter salt was characterized in detail as it was by far the most stable. The free acid HN(F)(NO2)was found to be unstable, as was the ammonium salt of fluoronitramide. The fluorine atom was shown to be capable of displacement by nucleophiles. In contrast to dinitramide, which at room temperature is unreactive towards aqueous alkali, fluoronitramide reacts instantly with aqueous hydroxide. Single crystal X-ray diffraction data show an unusual degree of uncertainty in the position of the fluorine atom in all of the salts that were examined.

: This work is focused on a continued, escalating effort to develop new energetic functional groups which offer enhanced energy, oxygen balance, and density in that order of priority. A continuation of the study of addition of nitrene precursors to N,N-dialkyl nitrosamines is described; the nitrene derived from 1-amino-3,5-dinitro-1 ,2,4-triazole has been approached by oxidation of the parent amine. Initial results were not successful; aminodinitrotriazole in the presence of lead tetra-acetate does not produce detectable yields of dinitrotriazolyl azoxy dimethyl amine when aminodinitrotriazole and lead tetra-acetate are reacted in the presence of N,N-dimethylnitrosamine. The synthesis of the 5-nitrotetrazole-2-N-oxide anion has been realized and optimized; it is carried out in water/potassium acetate buffer, and proceeds in 90% yield; due to the small enthalpy of this oxidation, scale up and heat dissipation do not present a problem. The density of hydroxyl ammonium 5-nitrotetrazole-2-oxide is 1.82 g/cc; its enthalpy of formation is +40 kcal/mole. Finally, a practical pathway to 1-alkoxy-5-amino tetrazoles has been developed; it is hoped that this will enable the synthesis of 5-nitrotetrazole-1 ,3-bis-N-oxides, a family of unprecedented materials with excellent heats of formation and oxygen balance that rivals ammonium perchlorate and ammonium dinitramide.

: Synthetic pathways to the nitroazoxyamine, pentazole-N-oxide, and triazanitrate anions have been explored at a fundamental level. The reaction of nitrene equivalents such as organic azides, N-haloamines, N-acyl hydroxylamines N,O-diacyl hydroxylamines, and amides in the presence of lead tetra-acetate or phenyliodine diacetate, acting on N,N dialkylnitrosoamines in an attempt to generate alkylazoxyamines have all been examined. Initial results were not encouraging; in response to this, the N,N-dialkylnitrosoamine was silylated, methylated, and acylated to give 1, 1-dialkyl-2silyloxy diazenium cation and its analogues. These cations were reacted with a wide array of nucleophillic nitrene equivalents such as fluoronitramide anion or monobromo-tert, butylamme; again, no azoxy amine was observed. Intramolecular versions of the above mentioned methodologies were contrived; the appropriate intermediates were synthesized, characterized, and subjected to a variety of conditions designed to effect the intramolecular synthesis of the alkylazoxyamine, a useful precursor to the heretofore unknown nitroazoxyamine (diazanitrate). Still, no obvious evolution of the desired azoxyamine was observed. Many variations remain to be explored. One clear success in this program was the invention of HYDROXYNITROUREA, a high density oxidizer with potential use as a replacement for perchiorate. Kilogram quantities were made and tested commercially; it tended to burn too fast at elevated pressures. The ammonium salt of HNU shows much promise as a bum rate attenuator, and this is presently being explored.