Copper 5-nitrotetrazolate

The other metallic salts of 5-nitrotetrazole can be prepared via the sodium salt according to the original von Herz procedure [45]. The sodium salt is prepared by the reaction of sodium hydroxide with acid copper 5-nitrotetrazole Cu(NT)2-HNT in an aqueous solution. The sodium 5-nitrotetrazole is isolated by crystallization [1, 46, 57, 63, 64]. The product can by purified by recrystallization from acetone [42] followed by filtration and precipitation by addition of hexane [64] or crystallized by evaporation of most of the acetone [56]. 

Copper(II), di-/Lt-bromobis[bromo(pyridine)-structure, 2, 108 Copper 8-hydroxyquinolinate biocidal activity mechanism, 1, 401 fungicide, 1, 399 Copper nitrotetrazole as propellants, 5, 837 Copper phthalocyanine, 1, 333-334 colour and constitution, 1, 345 Coproporphyrin, 4, 382 Coproporphyrin, dehydro-, 4, 382... 

Fig. 1.17 Molecular structures of lead styphnate (LS), lead azide (LA), an iron and copper nitrotetrazolate complexes as well as copper(I) 5-nitrotetrazolate (DBX-1) and potassium-7-hydroxy-6-dinitrobenzofuroxane (KDNP).

Given the role that low thresholds of 5-AT and 1H tetrazole impurities clearly play in the successful synthesis of DBX-1 from NaNT, we endeavoured to develop a procedure for synthesizing pure NaNT as efficiently as possible, while avoiding the tedious, time consuming, and reduced yield Cu11 titration and filtration, which is currently required. As an added refinement, we also desired to eliminate the handling of the intermediate acid salt of copper(II) 5-nitrotetrazolate, Cu(NT)2 HNT ... 

Sodium Nitrotetrazolate Dihydrate (NaNT) Anhydrous aminotetra-zole (8.48 g, 0.10 mol) and copper sulfate pentahydrate (0.2 g, 0.8 mmol) were added to a solution of nitric acid (9 mL, 65 %) in distilled water (60 mL). This was added to a pre-cooled solution of sodium nitrite (20.8 g, 0.30 mol) and cupric sulfate pentahydrate (11 g, 0.044 mol) in distilled water (100 mL). The solution was maintained at 15 to 18 °C during the addition by means of a cool water bath. After addition, the solution was stirred for 30 min at the same temperature... 

Nitrotetrazole is readily prepared from the diazotization of 5-aminotetrazole in the presence of excess sodium nitrite and is best isolated as the copper salt complex with ethylenediamine. The salts of 5-nitrotetrazole have attracted interest for their initiating properties. The mercury salt is a detonating primary explosive. The amine salts of 5-nitrotetrazole are reported to form useful eutectics with ammonium nitrate. ... 

Nitrotetrazole copper salt 2,4,6-Trinitro-lead-ll-resorcinate... 

Mercuric-5-nitrotetrazole [Structure (2.13)] was prepared according to the methods reported by Gilligan et al. [14] and Redman and Spear [15]. Thus, 5-aminotetrazole was treated with sodium nitrite and copper sulfate to obtain Cu(NT)2HNT-4H20 (where NT nitrotetrazole). The copper salt was subsequently converted to the ethylene diamine complex MNT was then obtained by treating the complex with mercuric nitrate in HN03 medium. The precursors and final product were air dried. The synthesis of these compounds is carried out in a fume hood behind a protective polycarbonate shield in a stainless steel reaction vessel. 

Preparation of sodium-5-nitrotetrazole dihydrate The diazotization of 5-ami-notetrazole monohydrate (AT) in the presence of excess of sodium nitrite and copper sulfate gives a complex cupric salt intermediate [Cu(NT)2 HNT-4H20] which is then converted to the sodium salt [NaNT-2H20]. 

Kamlet, Improved Method of Preparing the Acid Copper Salt of 5-Nitrotetrazole , PatAppl 794197 (1977) (AD-DOO-4164) 12) DJ. 

Nucleophilic substitution of the diazo group is practically the only method for the production of nitro derivatives of tetrazole [392, 436 143], 5-Nitrotetrazole itself was isolated and identified in the form of metallic salts [436-440, 442, 443], The mechanism of substitution of the diazo group by a nitro group in heterocyclic compounds has not been studied specially. As already mentioned, in many cases the reaction takes place as catalytic nucleophilic substitution and does not require the use of a catalyst (copper salts) [392,444], The results from investigation of the kinetics of the substitution of the diazonium group by the nitro group in compounds of the benzene series make it possible to suppose that the diazonitrite is formed intermediately and quickly reacts with a second nitrite anion [392,444], Some difference between the kinetics of the reaction of 3-diazonium-5-carboxy-l,2,4-triazole and 3-diazonium-5-methoxycarbonyl-l,2,4-triazole with sodium nitrite in hydrochloric acid and the analogous process in the benzene series is probably due to prototropic... 

In early days Alfred Nobel already replaced mercury fulminate (MF, see above), which he had introduced into blasting caps, with the safer to handle primary explosives lead azide (LA) and lead styphnate (LS) (Fig. 1.17). However, the long-term use of LA and LS has caused considerable lead contamination in military training grounds which has stimulated world-wide activities in the search for replacements that are heavy-metal free. In 2006 Huynh und Hiskey published a paper proposing iron and copper complexes of the type [cat]2[Mn(NT)4(H20)2] ([cat]+ = NH4, Na+ M = Fe, Cu NT = 5-nitrotetrazolate) as environmentally friendly, green primary explosives (Fig. 1.17) [3]. 

Another environmentally compatible primary explosive is copper(I) 5-nitrotetrazolate (Fig. 1.17). This compound has been developed under the name of DBX-1 by Pacific Scientific EMC and is a suitable replacement for lead azide. DBX-1 is thermally stable up to 325 °C (DSC). The impact sensitivity of DBX-1 is 0.04 J (ball-drop instrument) compared with 0.05 J for LA. The compound is stable at 180 °C for 24 hrs in air and for 2 months at 70 °C. DBX-1 can be obtained from NaNT and Cu(I)Cl in HC1/H20 solution at a higher temperature. However, the best preparation for DBX-1 in a yield of 80-90 % is shown in the following equation where sodium ascorbate, NaC6H706, is used as the reducing agent ... 

While free nitrotetrazole is extremely sensitive and only of limited thermal stability, the salts of nitrotetrazole are, at least thermally, often significantly more stable. The best synthetic route starts from 5-aminotetrazole via the corresponding copper salt (M = alkali metal) ... 

Compatibility of the silver salt of 5-nitrotetrazole has been investigated by Blay and Rapley [55]. They exposed a thin layer of AgNT on a metal surface at 50-60 °C to humid conditions for up to 8 weeks. They observed that it is incompatible with aluminum, the metal being corroded at humidity levels as low as 75% (significantly more than for SA). Copper and brass were less affected, and only at 100% relative humidity, and no corrosion of stainless steel was observed under the conditions of the test. The silver salt of 5-nitrotetrazole is compatible with HMX, RDX, and the lead salt of dinitroresorcine. However, when a mixture of AgNT with tetrazene was stored at high humidity, both tetrazene and AgNT rapidly decomposed, but a similar mixture stored at low humidity showed no decomposition. The silver salt of 5-nitrotetrazole is more resistant to rubbers and plastics than SA. Spectrophoto-metric determination of the silver salt of 5-nitrotetrazole has also been published by Blay and Rapley [55]. 

Free 5-nitrotetrazole can be prepared by treating a warm aqueous suspension of its acid copper salt with hydrogen sulfide [1, 45, 46]. If hydrochloric acid is used instead of hydrogen sulfide, the 5-nitrotetrazole becomes imstable and explodes without any external stimulus after a period of 2-3 weeks in storage [1,4]. 

Careful optimization of the process leads to efimination of the minor explosions and improved yield. The method itself has however been superseded by the diamine complex route. These complexes are synthesized by the reaction of acidic copper salt of 5-nitrotetrazole with the relevant diamine (mostly 1,2-ethylenediamine or less frequently 1,3-diaminopropane) in the presence of copper sulfate [4,40,41,46, 56,66]. These coordination compounds could be readily purified by recrystallization from water and they are safer and easier to handle in the dry state than the sodium salt (1,2-ethylenediamine complex only bums when impacted by 2.5 kg hammer from 50 cm) [42, 46]. 

Gilligan, W.H., Kamlet, M.J. Method of preparing the acid copper salt of 5-nitrotetrazole. US... 

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