Azides stability

Spontaneous explosions of azides Sensitivity of lead azide Stability and reactivity of lead azide The manufacture of lead azide Silver azide Cadmium azide Si[Pg.360]

The emphasis of work by French researchers has been the use of soft-donor extractants and complexants to enhance actinide/lanthanide group separation (Vitorge 1985, Musikas et al. 1980, Musikas 1985). The relative stability constants for lanthanide and actinide azide complexes reported by Musikas etal. (1980) suggest that hydrazoic acid could function as a useful reagent for this separation. This is confirmed in a later report for Am/Eu separation (Musikas 1985) in which americium extraction is suppressed by complex formation with azide. The separation factors are not very different from those reported by Sekine (1965) using SCN as the complexant in TBP extraction. However, Choppin and Barber (1989) find that, while the trivalent actinide-azide stability constants are somewhat larger than those of the trivalent lanthanides, the complexation enthalpies calculated from the temperature coefficient of the / s do not support the existence of a covalent bonding contribution. 

The 2,6-dimethylbenzyl ether is considerably more stable to hydrogenolysis than is the benzyl ether. It has a half-life of 15 h at 1 atm of hydrogen in the presence of Pd-C whereas the benzyl ether has a half-life of —45 min. This added stability allows hydrogenation of azides, nitro groups, and olefins in the presence of a di-methylbenzyl group. ... 

Copper amine azide Copper tetramine nitrate Crotonaldehyde, stabilized Cyanogen bromide Cyanuric triazide... 

Sulfinyl azides have higher thermal stability than their divalent counterparts. For example, benzenesulfmyl azides ArS(0)N3 (Ar = Ph, 4-MeCelFt, 4-NO2C6H4), which are obtained by the metathetical reaction of the sulfinyl chloride and sodium azide in acetonitrile, can be stored in the solid state at low temperatures. ... 

Although bulky aryl groups, e.g., mesityl, are not effective in stabilizing arylselenium (II) azides, the use of intramolecular coordination in 2-Mc2NCH2C6H4SeN3 has enabled the first structural characterization of this reactive functionality. The Se-Ns (azide) bond length is 2.11 A, while the intramolecular Se N distance is 2.20 A, cf. 2.14 A in the arylselenium bromide 15.5, and 2.13 A and 2.17 A, respectively, in the corresponding chloride and iodide. This... 

This derivative is most conveniently prepared by reacting an azide with tri-phenylphosphine. It was used because of its stability towards Ph2PLi. Its aqueous hydrolysis is well documented. ... 

The 1,2,3,4-thiatriazoles are unstable. They decompose on heating— in some cases even at room temperature—and in many cases they melt with detonation. Accordingly the Ng-group has not been stabilized much by ring closure. The compounds behave in this respect similarly to azides and this fact doubtlessly delayed the recognition of their true nature. On heating with a solvent the thermal decomposition of 5-aryl-1,2,3,4-thiatriazoles proceeds according to Eq. (4). By the photochemical decomposition small amounts of the isothiocyanate, RNCS, are formed in addition to the nitrile. ... 

Because of resonance stabilization of the anion, a tet-nazolyl moiety is often employed successfully as a bioisosteric replacement for a carboxy group. An example in this subclass is provided by azosemide (27). Benzonitrile analogue is prepared by phosphorus oxychloride dehydration of the corresponding benzamide. Next, a nucleophilic aromatic displacement reaction of the fluorine atom leads to The synthesis concludes with the 1,3-dipolar addition of azide to the nitrile liinction to produce the diuretic azosemi de (27). ... 

Photolysis of aryl azides in amine solution, with a tertiary amine as cosolvent to promote stabilization of the singlet nitrene, has met with some success. For example, the yield of 2-piperidino-3 W-azepme. obtained by the photolysis of phenyl azide in piperidine, is increased from 35 to 58% in the presence of A A /V. /V -tetramethylethylenediamine (TMLDA).180 Also, an improved yield (36 to 60 %) of A,(V-diethyl-3W-azepin-2-amine (38, R = Et) can be obtained by irradiating phenyl azide in triethylamine, rather than in dicthylaminc, solution.181 Photolysis (or thermolysis) of phenyl azide in TMEDA produces, in each case, 38 (R = Et) in 40% yield.181 In contrast, irradiation of phenyl azide in aniline with trimethylamine as cosolvent furnishes jV-phenyl-377-azepin-2-amine (32, R = Ph) in only low yield (2%).35... 

Since the mid-1990s, synthetic attention has been directed more towards the use of metal-stabilized nitrenes as synthetic effectors of alkene aziridination. In 1969 it was reported that Cu(i) salts were capable of mediating alkene aziridination when treated with tosyl azide, but the method was limited in scope and was not adopted as a general method for the synthesis of aziridines [12]. Metaloporphyrins [13] were shown to be catalysts for the aziridination of alkenes in the presence of the nitrene precursor N-tosyliminophenyliodinane [14] in the early 1980s, but the reaction did... 

Azide is widely useful as a surrogate for ammonia in nucleophilic substitution reactions, due to its high nucleophilicity, low basicity, and stability towards a variety of conditions for subsequent transformations. In particular, the azidolysis of... 

Mercury (Quicksilver, Hydrargyrum), Hg, at wt 200.61, silvery liq, mp —38.87°, bp 356.9°, d 13.546g/cc at 20°. Insol in w, HC1, ale and eth sol In nitric acid. Sometimes found native poisonous. Can be prepd by heating the ore cinnabar (HgS) either in air or with lime. Forms numerous salts, some of which are very expl, eg, Hg fulminate, Hg azide, etc. The presence of Hg in expls, even in minute quants, is unde-sireable because it affects the result of thermal stability tests. Marshall (Ref 1) describes various tests used in Engl and Ger for its detection in different expls and propints Refs 1) Marshall 2, 708-12(1917) 2) Mellor... 

Esters of a-diazoalkylphosphonic acids (95) show considerable thermal stability but react with acids, dienophiles, and triphenylphosphine to give the expected products. With olefinic compounds in the presence of copper they give cyclopropane derivatives (96), but with no such compounds present vinylphosphonic esters are formed by 1,2-hydrogen shift, or, when this route is not available, products such as (97) or (98) are formed, resulting from insertion of a carbenoid intermediate into C—C or C—H bonds. The related phosphonyl (and phosphoryl) azides (99) add to electron-rich alkynes to give 1,2,3-triazoles, from which the phosphoryl group is readily removed by hydrolysis. 

---