Lead acetate azide

Lead acetate azides, Pb(OAc)4 (N3)n, prepared in situ from lead tetraacetate and azidotrimethylsilane, react with alkenes to yield a variety of products, depending on the structure of the alkene 1,2-diazides. 1,2-acetoxy azides, a-azido ketones, allylic azides, and <5-oxo nitriles (by the oxidative cleavage of cyclohexene rings)97. The diazides and acetoxy azides are formed by preferential syn addition, but the diastereoselectivity (up to 3 1) is far from satisfactory with both acyclic and cyclic alkenes98,99. 

Ma.nufa.cture. Lead azide is typically made from sodium azide [26628-22-8] in small (eg, 5 kg) batches buffered by the reaction solutions of lead nitrate or lead acetate ... 

Lead azide is manufactured by reaction of sodium azide with either lead nitrate or lead acetate. It is a white crystalline solid, insoluble in cold water and stable on storage. It is very sensitive to friction and impact and has a velocity of detonation, when pressed to a density of 3-8, of4500 ms 1. 

Commercially, lead azide is usually manufactured by precipitation in the presence of dextrine, which considerably modifies the crystalline nature of the product. The procedure adopted is to add a solution of dextrine to the reaction vessel, often with a proportion of the lead nitrate or lead acetate required in the reaction. The bulk solutions of lead nitrate and of sodium azide are, for safety reasons, usually in vessels on the opposite sides of a blast barrier. They are run into the reaction vessel at a controlled rate, the whole process being conducted remotely under conditions of safety for the operator. When precipitation is complete, the stirring is stopped and the precipitate allowed to settle the mother liquor is then decanted. The precipitate is washed several times with water until pure. The product contains about 95% lead azide and consists of rounded granules composed of small lead azide crystals it is as safe as most initiating explosives and can readily be handled with due care. 

The crystalline product appears less stable than the diazide, spontaneously decomposing, sometimes explosively [1], It was rated as too unstable for use as a practical detonator or explosive [2], Lead(IV) acetate azide (probably the triacetate azide) is also rather unstable, evolving nitrogen above 0°C with precipitation of lead(II) azide [3], Lead(IV) azide will be considerably more endothermic than the lead(II) salt. 

This primary explosive is created by adding lead acetate to a solution of sodium or ammonium azide. Lead azide has a good shelf life in dry conditions but is unstable in the presence of moisture, oxidizing agents, and ammonia. It is less sensitive to impact than mercury fulminate, but more sensitive to friction. Since lead azide is a nonconductor, it may be mixed with flaked graphite to form a conductive mixture for use in low-energy electronic detonators. 

Lead(IV) acetate azide, 2402 Lead (II) azide, 4782 Lead(IV) azide, 4790 Lithium azide, 4685... 

Dioxane, Potassium nitrite. Potassium bicarbonate, Tetranitromethane Lead acetate. Sodium azide... 

Nitronium tetrafluoroborate. Acetonitrile, Ammonium carbonate. Potassium carbonate. Diethyl ether, Acetone, Ethyl acetate. Butanol Sulfamic acid, Potassium hydroxide. Ethanol, Nitric acid, Sulfuric acid, Acetone, Isopropyl alcohol Dioxane, Potassium nitrite. Potassium bicarbonate, Tetranitromethane Lead acetate, Sodium azide Sodium azide, Lead acetate. Water... 

Sodium azide, Lead acetate, Water Picric acid. Sodium hydroxide. Lead nitrate Styphinic acid. Sodium hydroxide, Lead-II-nitrate Styphinic acid. Magnesium carbonate. Lead nitrate. Nitric acid Phloroglucinol, Glacial acetic acid. Sodium nitrite. Lead nitrate Acetylene, Arsenic trichloride. Mercuric chloride. Hydrochloric acid... 

Lead azide [Pb(N3)2] (LA) is a salt of hydrazoic acid (N3H, highly poisonous) and is prepared by reacting solutions of sodium azide and lead acetate or nitrate. This exists in two forms the a form (orthorhombic and stable) and P form (monoclinic) which has a tendency to revert back to the a form. The P form is much more sensitive. The two forms differ in their rate of decomposition when heated. Crystalline LA is stored in dry conditions because it becomes more sensitive when... 

Service lead azide (SLA) SLA is prepared by double decomposition of lead acetate and sodium azide in the presence of sodium carbonate and acetic acid. 

Lead azide can exist in two allotropic forms the a-form is orthorhombic, the / -form monoclinic. (Miles [75], Garner and Gomm [37]). The crystallographically stable modification is the a-form. It is prepared by rapidly stirring a solution of sodium azide with a solution of lead acetate or lead nitrate. 

According to Sudo [96] lead azide prepared by the action of sodium azide on an aqueous solution of lead acetate has a lower ignition temperature (332-336°C) than that obtained by the action on a solution of lead nitrate (339-359°C). 

Fig. 48. Lead azide precipitated in different conditions, according to Sudo[96] (a)— from high concentration of lead acetate (10%) and low of sodium azide (4%) (b)— from low concentration of lead acetate (4%) and high of sodium azide (10%) (c)— from low concentrations of lead acetate (4%) and sodium azide (2%) (d)—from high concentrations of lead acetate (25%) and sodium azide (10%) in the presence of gelatine (5%) (e)—from high concentrations of lead nitrate (25%) and sodium azide (10%) in the presence of gelatine (5%) (very small crystal form).

According to Sudo [96] spontaneous explosion can occur during the formation of lead azide from sodium azide and lead acetate, when the concentration of reacting solutions is high (10% or more). 

Pure lead azide may be produced in the same equipment, but instead of lead nitrate and dextrin lead acetate is employed. The precipitation temperature is lower than in the manufacture of technical-grade lead azide (having a purity of less than 95%). All other operations are the same as already described. 

Curtius added lead acetate to a solution of sodium or ammonium azide resulting in the formation of lead azide. In 1893, the Prussian Government carried out an investigation into using lead azide as an explosive in detonators, when a fatal accident occurred and stopped all experimental work in this area. No further work was carried out on lead azide until 1907 when Wohler suggested that lead azide could replace mercury fulminate as a detonator. The manufacture of lead azide for military and commercial primary explosives did not commence until 1920 because of the hazardous nature of the pure crystalline material. 

Lead azide can exist in two allotropic forms the more stable a-form which is orthorhombic, and the /1-form which is monoclinic. The a-form is prepared by rapidly stirring a solution of sodium azide with a solution of lead acetate or lead nitrate, whereas the /1-form is prepared by slow diffusion of sodium azide in lead nitrate solutions. The /1-form has a tendency to revert to the a-form when its crystals are added to a solution containing either the a-form crystals or a lead salt. If the /1-form crystals are left at a temperature of 160 °C they will also convert to the a-form. Some of the properties of lead azide are presented in Table 2.3. 

BASF see Badische aniline-und sodafabrik 2 B4 Bashforth chronograph see Chronographs 3 C308 Basic cupric azide 1 A533 Basic lead acetate 1 A28 Basic lead azide 1 A555... 

Lead azide is produced as a white precipitate by mixing a solution of sodium azide with a solution of lead acetate or lead nitrate. It is absolutely essential that the process should be carried out in such manner that the precipitate consists of very small particles. The sensitivity of lead azide to shock and to friction increases rapidly as the size of the particles increases. Crystals 1 mm. in length are liable to explode spontaneously because of the internal stresses within them. The U. S. Ordnance Department specifications require that the lead azide shall contain no needle-shaped crystals more than 0.1 mm. in length. Lead azide is about as sensitive to impact when it is wet as when it is dry. Dextrinated lead azide can apparently be stored safely under water for long periods of time. The belief exists, however, that crystalline service azide becomes more sensitive when stored under water because of an increase in the size of the crystals. 

Lead Tetrazyl Azide. Pb(CN7) v si sol in acet, eth, ethanol, w and most org solvents. Prepn is by addn of a Pb nitrate soln to an aq soln of Tetrazyl Azide. The salt explds on heating, and has an impact sensy of 100cm with a 5kg wt Silver Tetrazyl Azide. AgCN7 mw 217.95 N... 

While the environmental impact of cadmium azide in deep oil deposits is relatively low, the long-term use of Pb(N3)2 and lead styphnate in military training grounds has resulted in considerable lead contamination (see Ch. 1.2.3, see Fig. 1.17). On demand lead azide (ODLA) is available from the reaction of lead acetate and sodium azide. The recently introduced iron and copper complexes of the type [Cat]2 [Mn(NT)4(H20)2] ([Cat]+ = NH4, Na+ M = Fe, Cu NT = 5-nitrotetra-zolate) as green primary explosives [3] are relatively easily obtained and show similar initiator properties as those of lead azide (Tab. 2.2). 

Introduction of oxygen into a Minisci-type reaction mixture leads to formation of amino ketones (Scheme 94). The mixed acetate/azide of lead(IV) with styrene in acetonitrile at -20 C yields phen-acyl azide (60%). One example of azirine formation has already been discussed (Scheme 87). Other related syntheses from vinyl azides are included in a recent review. ... 

Steroidal alkenes, with lead(IV) azide/acetate, can yield cleaved derivatives such as (87),or its des-azido analog, or the uncleaved azido ketone,or the allylic azide, according to conditions, as well as the 1,2-diazi s mentioned earlier (Section 3.S.3.2). 

The reagent reacts also with Iriple bonds The temperature of the reaction determines the product Composition. Thus the main product of the reaction of diphcnylacetylene (6) with lead(lV) acetate azide at 20° is benzonitrile, formed by fragmentation of diazidostilbene. The products obtained from the reaction at - 20° are formulated. 

---