Silver azide preparation

Impact sensitivity significantly depends on many aspects. Let us look at some of these properties starting with crystal size of the material under test. Colloidal silver azide prepared from concentrated solutions exhibits significantly lower sensitivity (0.5 kg from 77.7 cm) than coarser crystals prepared from diluted solutions, which required less than half the energy (0.5 kg fi om 28.5 cm). MF measured under the same conditions for comparison required 12.7 cm with the 0.5 kg hammer [20]. It is interesting to note that the impact sensitivity of S A (in fine powdery form), which is considered very sensitive, is lower than that of MF. Similar investigations have... 

Silver azide prepared by direct reaction of sodium azide and the soluble silver salt forms as a fine powder with a low bulk density. This is caused by its extremely low solubility and a tendency to nucleate profusely which results in extensive nucleations and very small crystals. Several processes have been developed for preparation of a product with a more suitable crystal structure. 

The azides are salts which resemble the chlorides in solubility behaviour, for example silver azide, AgNj, is insoluble and sodium azide, NaN3, soluble in water. Sodium azide is prepared by passing dinitrogen oxide over molten sodamide ... 

Silver Azide. Silver a2ide, AgN, is prepared by treating an aqueous solution of silver nitrate with hydrazine (qv) or hydrazoic acid. It is shock-sensitive and decomposes violendy when heated. 

The use of azide reagents is also important for the synthesis of cyclic sulfur(VI)-nitrogen systems. The reaction of SOCI2 with sodium azide in acetonitrile at -35°C provides a convenient preparation of the trimeric sulfanuric chloride [NS(0)C1]3 (Eq. 2.16). " Thionyl azide, SO(N3)2 is generated by the heterogeneous reaction of thionyl chloride vapour with silver azide (Eq. 2.17). This thermally unstable gas was characterized in situ by photoelectron spectroscopy. The phenyl derivative of the six-membered ring [NS(0)Ph]3 can be prepared from lithium azide and PhS(0)Cl. ... 

Silver Azide, Cadmium Azide, Cupric Azide, Triazidotrinitrobenzene, Chloratotrimercuraldehyde, Nitrogen Suifide Hexamethylenetriperoxidediamine Until WWI, Mercuric Fulminate was the principle initiating agent used, but Lead Azide has now replaced it. Lead azide is not the most powerful azide, but is more stable and less dangerous to handle than some of the other ones. Cadmium Azide, for example, is more powerful than Lead Azide but is unsuitable as an initiating agent because it is difficult to prepare and is soluble in water... 

Alkyl and aryl azides are prepared by the nucleophilic displacement by azide ion on halide, sulfate, phenyldiazonium, hydroxyl, nitrate, iodoxy, alkoxy, and tosylate groups [6]. Sodium azide is the most useful and practical reagent. The use of silver azide is not necessary in most cases. Some examples from the literature [8-33] employing these methods are shown in Table I. 

Silver azide can be readily prepared by precipitation from aqueous solutions containing silver and azide ions. Recrystallization from aqueous ammonia affords colourless plates and needles. It was found to be potentially explosive and often detonated when subjected to shock.131... 

Silver azide is sensitive to light, insoluble in water, and soluble in ammonia, from which it can be recrystallized. It is prepared from sodium azide and solutions of silver salts (depending on the working conditions) as a cheesy, amorphous precipitate. 

An alternative method for carrying out the silver mirror test is the following. Prepare ammoniacal silver nitrate solution by placing 5 ml silver nitrate solution in a thoroughly clean test-tube and add 2-3 drops of dilute sodium hydroxide solution add dilute ammonia solution dropwise until the precipitated silver oxide is almost redissolved (this procedure reduces the danger of the formation of the explosive silver azide, AgN3, to a minimum). Introduce about 0-5 ml neutral tartrate solution. Place the tube in warm water. A silver mirror is formed in a few minutes. 

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. 

Silver azide was first prepared in 1890 by Curtius [14] by passing HN, into silver nitrate solutions. Various other methods (discussed in Volume 1, Chapter 1) were developed, but the most feasible is the reaction of the readily available sodium azide with silver nitrate. 

Properties Lead azide Silver Azide Experimental preparation ... 

In Chapter 1 different processes of preparing silver azide are described, and the impact sensitivities of samples made by processes are presented in Figure 12. They were tested with the Picatinny Arsenal apparatus and also with the ball-drop apparatus. 

Of historic interest is a reaction in which the azide group was synthesized from hydrazine and nitrite in the presence of silver ions [19,98] (see p. 24). Most commonly, silver azide is prepared by mixing aqueous solutions of hydraz-oic acid or sodium azide with silver nitrate. The product is precipitated in fine crystalline form larger crystallites are obtained from more dilute reagents [200]. One author recommended the use of an excess of silver nitrate another believed this would enhance the photodecomposition of the product [202]. Of more significance is the recommendation to make the azide in the dark, or at least under red light, [203,204] and to wash the product completely ion free. 

The preparation [205] of 45-g batches of silver azide takes place at room temperature in a 4-liter beaker equipped with a stirrer. Silver nitrate, 51.1 g dissolved in 1 liter water, is placed in the beaker and 19.5 g sodium azide, dissolved in 1 liter water, is added with rapid stirring within 45 min. The product is isolated as above. 

The disorder produced by irradiation has been studied in only a limited number of the explosive azides. The selection of the azides for investigation has undoubtedly been determined by their usefulness for civilian and military applications. Hence silver azide, and, in particular, lead azide, have been studied. Other factors, such as ease of preparation, ease of handling, similarities in properties to azides of practical importance, and purely fundamental considerations have played a roll in the selection of materials. In addition to lead and silver azide only thallium and barium azides have Keen studied to any extent, and this section is devoted almost exclusively to these four materials. All results are for a-Pb(N3)2 unless otherwise stated. 

Impurities sensitize some azides. For example, Gray and Waddington [18] introduced thallous sulfide into thallous azide and found that the initiation temperature was lowered. For pure lead azide the initiation temperature was 763°K whereas for the impure lead azide it was 693°K. Similarly, lead azide crystals containing 1% of carbon particles of size less than 1 /im initiate at temperatures below that of the pure lead azide [19]. An interesting method for introducing small quantities of impurities into silver azide was used by Deb et al. [20]. They prepared silver azide by using radioactive Ag, which decays by j3-emission into Cd. This method allowed 10" % of impurity to be introduced. It is important that even such small quantities affected not only the sensitivity but also the... 

Silver azide (SA) was first prepared by Curtius in 1890 by passing azoimide into a silver nitrate solution [1]. 

---