Alkali metals azides

Deb [1238] prepared thin films of inorganic azides (for optical studies) by reaction of an alkali metal azide with a heavy metal iodide, e.g. 

The synthesis of aryloxysulphonyl azides, which can be used as precursors for sulphamates, is improved by the use of tetra-n-butylammonium azide under homogeneous conditions in place of an alkali metal azide [ 1 ]. A stoichiometric amount of the ammonium azide is used and no attempts appear to have been made to conduct the reaction under solid liquid phase-transfer catalytic conditions. 

Alkyl azides are conveniently prepared from the reaction of alkali metal azides with an alkyl halide, tosylate, mesylate, nitrate ester or any other alkyl derivative containing a good leaving group. Reactions usually work well for primary and secondary alkyl substrates and are best conducted in polar aprotic solvents like DMF and DMSO. The synthesis and chemistry of azido compounds is the subject of a functional group series. ... 

Carbon disulfide is an extremely flammable liquid, the closed cup flash point being -22°F (-30°C). Its autoignition temperature is 90°C (194°F). Its vapors form explosive mixtures with air, within a wide range of 1.3 to 50.0% by volume in air. Reactions with certain substances can progress to explosive violence. They include finely divided metals, alkali metals, azides, fulminates, and nitrogen dioxide. 

Either alkali metal azides or Me3SiN3 can be used for ring opening of epoxides by the azide ion to yield 2-azido ethanols. With the latter reagent the corresponding trimethylsilyl ethers can be obtained instead of the alcohols. 

Most epoxides react with alkali metal azides or Me3SiN3 only sluggishly, and different catalysts have been recommended, for example quaternary ammonium salts [248, 366], A1C13 [367], and copper(II) salts [368]. Other reagents are given in Schemes 4.84 and 4.85. 

Alkali metal azides, 1 79 2 139 Alkali metal cyanates, 2 86 Alkali metal pyrosulfites, 2 162 Alkali metal sulfites, 2 162 Alkaline earth azides, 1 79 Allanite, extraction of, 2 44 Allophanyl azide, formation of, from allophanyl hydrazide, 5 51 Allophanyl hydrazide (1-amino-biuret), 5 48 hydrazones of, 5 51 from methyl and ethyl alloph-anates, 5 50 salts of, 5 51... 

CA 50, 12482 (1956) (Flame propagation in ozone) 29)Sax (1957), 161-61 (Destruction of expls) 30)F.C.Ikle, "The Social Impact of Bomb Destruction , Univ of Oklahoma Press, Norman, Okla (1958) 3l)Anon, Ordnance Service in the Field , US Army Field Manual FM 9-1 (1959) (Destruction of ammo) 32)Anon, Ordnance Ammunition Service , FM 9 5 (1959) (Destruction of ammo) 33)A.B.Amster, "Relationship Between Decomposition Kinetics and Sensitivity (U), Stanford Research Institute, Menlo Park, California,Repts (1962), Contract No Nonr 3760(00) (Conf, not used as a source of info) 34)P.W.M.Jacobs A.R.T.Kureishy, Kinetics of Thermal and Photochemical Decomposition of Some Alkali Metal Azides , Imperial College, London, England, Final Tech Rept (1964) Contract DA-91-591-EUC-2059 34a)Anon, Care, Handling, Preservation and Destruction of Ammunition , TM 9-1300-206 (1961) 35)-Anon, Investigations of the Mech-... 

Azides are salts of hydrazoic acid (N3H). Alkali metal azides are the most important intermediates in the production of->- Lead Azide. 

The product can be obtained by treating 2,4,6-trichloro- 1,3,5-trinitrobenzene with an alkali metal azide in alcoholic solution. It is a lead-free - initiating and powerful explosive and does not produce toxic fumes (- Lead-free Priming Compositions). The product undergoes a slow conversion into hexanitrosobenzene,... 

Alkali metal azides are not explosive, sodium azide for example decomposing at ca. 300°C to give Na and N2. Tetramethylammonium azide27 can be made in high yield and purity ... 

Kinetics of Thermal and Photochemical Decomposition of Some Alkali Metal Azides", Imperial College, London, England, Final Tech Rept (1964) Contract DA-91-591-EUC-2059... 

The lattice energies of the alkali metal azides have been evaluated by Gray and Waddington (45), (i) by direct computation, using the... 

The Lattice Energies (kcal/mole) of the Alkali Metal Azides... 

Hydrazoic acid and its alkali metal salts are often used in azide synthesis. Pure hydrazoic acid is violently explosive and the reagent is consequently used in dilute solution in which it is quite stable. Solutions of hydrazoic acid in organic solvents may be conveniently prepared and find general application in azide synthesis " . Silver azide, which has occasionally been used for the preparation of organic azides, is impact sensitive and has been superseded by the alkali metal azides which are not considered explosive under most laboratory conditions. 

Alkali metal azides react with epoxides in a appropriate solvent to give vicinal azidohydrins. Phase-transfer reagents may be used. The reactions usually require high temperatures and/or long reaction times. 

The various phase transfer techniques also led to very good results in azide synthesis. Excellent yields of alkyl azides were secured, for instance, when alkyl bromides were treated with alkali metal azides in the presence of catalytic amounts of tetrabutylammonium bromide or aliquat 336 (equation 29). "- The use of crown ethers has been described as well. "... 

Azides are salts of hydrazoic acid (N3H). Alkali metal azides are the most important intermediates in the production of -> Lead Azide. Sodium azide is formed by the reaction between sodium amide (NaNH2) and nitrous oxide (N20). Sodium amide is prepared by introducing gaseous ammonia into molten sodium. 

In the alkali metal pseudohalides the contribution of cationic wave functions to the valence band structure can be neglected. The optical absorption spectra can therefore be correlated to transitions involving excited states of the anions. However, one can see solid state effects like the superposition of vibronic structure on the molecular symmetry forbidden transition at 5.39 eV in the crystal spectra of the alkali metal azides (76). In the more complex heavy metal and divalent azides, a whole range of optical transitions can occur both due to crystal field effects and the enhanced contributions from cationic states to the valence band. Detailed spectral measurements on a-PbNe (80), TIN3 (57), AgNs (52), Hg(CNO)2 (72) and AgCNO (72) have been made but the level assignments can at best be described as tentative since band structure calculations on these materials are not available at present. 

Ni and CNO can exist in a metastable state in ionic lattices. Among the azides, the anion is essentially unperturbed in the alkali metal salts but in the more complex heavy metal salts increasing perturbation of the anion occurs which is reflected in the asymmetric intraionic distances of the divalent salts in particular. This may be one of the reasons why the heavy metal salts are unstable with respect to the alkali metal azides. It is therefore pertinent to note that among the divalent azides the thermal sensitivity increases with the increasing asymmetry of the azide ions which increases in the order BaNe < PbNe < CuNe (c/. Table 2). Electron microscopic observations on thallous azide crystals have shown that the cubic form of the salt is relatively stable compared with the low temperature orthorhombic form (85). This is probably associated with the existence of asymmetric azide ions in the latter poljmiorph (c/.) Section IID). 

Both cadmium azide and mercury(II) azide are sensitive explosives, and no attempts have been made to determine optimum crystal-growth parameters for them. Precipitation studies have shown that large cadmium azide particles are more sensitive than smaller ones. Deb [33] has succeeded in preparing thin films by a displacement reaction. This is accomplished by evaporating successive thin films of an alkali-metal azide and the corresponding halide. Better-quality films... 

The cations of non-alkali-metal monovalent azides tend to form directed bonds with partial covalent character. Consequently the molecular packing of these crystals is slightly deformed from those of alkali metal azides with comparable size cations, as is seen in the structures of TIN3 (phase II), AgNa, CuNa, and NH4Na. The ionic radius of the Cu cation is 0.96 A, which is slightly larger than that of Na (0.95 A) and much less than that of (1.33 A). Hence the crystal structure of CuNa is intermediate between the NaNa and KNa types. 

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