Cupric hydrazoate

Cupric hydrazoate, Cu(Ns)a.—The only cupric nitride known is the hydrazoate, a highly explosive substance of deep reddish-brown colour. It is formed by dissolving copper in hydrazoic acid, and by the action of sodium hydrazoate on cupric sulphate.4... 

Lead azide tends to hydrolyze at high humidities or in the presence of materials evolving moisture. The hydrazoic acid formed reacts with copper and its alloys to produce the sensitive cupric azide [14215-30-6] Cu(N2)2- Appropriate protection must be provided by hermetic sealing and the use of noncopper or coated-copper metal. 

Curtius and Rissom [41] prepared cupric azide by the action of an aqueous solution of sodium azide on an aqueous solution of cupric sulphate, obtaining the salt in a hydrated form. The anhydrous salt was prepared by Straumanis and Ciru-lis [125] in the form of dark brown, reddish sediment by reaction of lithium azide on cupric nitrate in an alcohol solution. Another method described by Curtius consists of reacting hydrazoic acid with metallic copper in an aqueous medium. 

Green cupric azide has also been described (Dennis and Isham [44]). It is formed by the action of hydrazoic acid on cupric hydroxide or (according to Straumanis and Cirulis) on cupric oxide. It is sometimes grey in colour. 

Cupric Amminoazide (Ammoniate of Copper Azide), Diammine copper azide, [Cu(NHj)a] (Nj)a, mw 181.65, N 61.69% green crysrs, expl when heated or struck. Obtained by Dennis Isham (Ref 2) by shaking freshly pptd black cupric hydroxide, while still moist, with ao excess of hydrazoic acid, and washing and dissolving the ppt in aq ammonia. This compd was also prepd by Browne et al (Ref 6) and studied by Strecker Schwinn (Ref 8) and by Straumanis Cirulis (Ref 11) (See also Ref 21, p 149 and Table D under Ammines in this dictionary). Tetrammine copper azide, [Cu(NHs),](N3)a, mw 215.72, N 64.90%, blue crysts, expl at 202° and on impact. Prepd by Strecker Schwinn (Ref 8) and by Straumanis Cirulis (Ref 11) from cupric azide and NHS, (either liq or the dry gas). Only the di- and tetrammino- compds were prepd, (See also Ref 21, p 149 and Table D under Ammines)... 

Krupko (Ref 3) on heating cupric azide in w at 70-80°, followed by drying in air free from C0lt until hydrazoic acid is evolved. This compd expl at 7 to 8 cm under 1 kg impact... 

F. Martin gave 174° for the temp, of explosion. According to L. Wohler and W. Krupko, basic cupric azide, cupric oxyazide, CuO.CuNg, is formed as a yellow hydrated substance when water with normal cupric azide in suspension is heated to 70°-80° in a current of air freed from carbon dioxide until the calculated quantity of hydrazoic acid has been evolved. It inflames at 245°. L. M. Dennis and H. Isham obtained cupric amminoazide,Cu(NHg)Ns,by shaking freshly precipitated black cupric hydroxide, while still moist, with an excess of hydrazoic acid and washed the precipitate. A soln. of the precipitate in aq. ammonia deposits crystals of the salt. It explodes when heated or struck. It is insoluble in water, and soluble in dil. acids,... 

Aromatic hydrazines like hydrazobenzene are readily oxidized to azobenzenes with air in the presence of alkali or by the action of sodium hypobromite. Aliphatic azo compounds are also prepared from the corresponding hydrazo compounds. Thus azomethane, CH5N=NCHj, is jjte-pared by the oxidation of sym-dimethylhydrazine with cupric chloride (70%). The oxidation of -hydrazotoluene, CjHsCHjNHNHCHjCjHs, to the azo compound is accomplished with mercuric oxide in boiling ether (76%). ... 

Hydrazo compounds are dehydrogenated to azo compounds by many oxidants. 2,2 -Bisazopropane is prepared by the oxidation of sym-diiso-propylhydrazine with cupric oxide (equation 491) [i5(9]. 

Cupric azide, with or 1 mol HjO, was first prepd in 1898 by Cuttius Rissom (Ref 1) by mixing dil aq solns of Cu sulfate and Na azide, washing the ppt with ice w and drying it in a desiccator (Ref 18) They also obtd it by the action of 3.87% hydrazoic acid on Cu tptd by Zn. Browne et al (Ref 6) found that, in addn to Cu(Ns), some CuNj was... 

Both the above techniques require standardization using a known quantity of sodium azide carried through the same procedure. A semimicro gas-evolution method has been described by Blais [24] which utilizes only a few milligrams of lead azide. Nitrogen is determined by reduction of hydrazoic acid with heated cupric oxide. 

Turrentine and Moore reported different reaction the metallic copper reduces hydrazoic acid and yields cupric azide, ammonium azide, and nitrogen as its reduction products [109]. 

Cupric azide Cu(N3)2 forms by exposing finely grotmd CuO to hydrazoic acid. The Cu(N3)2 forms after several days [15, 101, 102, 108]. 

The product of the above reaction is, however, contaminated with a hydrolyzed surface layer (the product often has a yellow tinge). This layer can be removed by adding hydrazoic acid and letting the mixture stand for one day. Another possibility for precipitation of pure cupric azide is using a mixture of hydrazoic acid with sodium azide (pH 4.5-5.5) on cupric perchlorate. The product forms in the form of clusters of Cu(N3)2 needles [107]. Hydrolysis may be prevented by carrying out the reaction in a nonaqueous medium [15] the dried product must be stored in a desiccator [107]. Cu(N3)2 may be prepared by the reaction of sodium azide with cupric perchlorate in acetone [112] or by the reaction of cupric nitrate with lithium azide in ethanol [102]. 

Laboratory preparation of basic cupric azides is based on the reaction of a soluble copper salt with sodium azide (or hydrazoic acid) in presence of a hydroxide (sodium, barium). The reactiOTi conditions influence the type of basic cupric azide formed [15, 108]. 

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