Sodium azide, decomposition

Benzo-fused azoniaazulenes were also reported. o-Benzylphenyl azide 260 (92%) was obtained by diazotization of 259 followed by treatment with sodium azide. Decomposition of the azide 260 at 190°C gave azepinoindole 261, which was hydrolyzed to afford dihydroazepinoindolone 262 (90%). Dehydrogenation of262 with dichlorodicyanobenzoquinone yielded azepi-... 

The air bag industry has become one of the principal users of pyrotechnic compositions in the world. Most of the current air bag systems are based on the thermal decomposition of sodium azide, NaN, to rapidly generate a large volume of nitrogen gas, N2. Air bag systems must function immediately (within 50 ms) upon impact, and must quickly deploy a pulse of reasonably cool, nontoxic, unreactive gas to inflate the protective cushion for the driver or passenger. These formulations incorporate an oxidizer such as iron oxide to convert the atomic sodium that initially forms into sodium oxide, Na20. Equation 1 represents the reaction. 

Corrosion products and deposits. All sulfate reducers produce metal sulfides as corrosion products. Sulfide usually lines pits or is entrapped in material just above the pit surface. When freshly corroded surfaces are exposed to hydrochloric acid, the rotten-egg odor of hydrogen sulfide is easily detected. Rapid, spontaneous decomposition of metal sulfides occurs after sample removal, as water vapor in the air adsorbs onto metal surfaces and reacts with the metal sulfide. The metal sulfides are slowly converted to hydrogen sulfide gas, eventually removing all traces of sulfide (Fig. 6.11). Therefore, only freshly corroded surfaces contain appreciable sulfide. More sensitive spot tests using sodium azide are often successful at detecting metal sulfides at very low concentrations on surfaces. 

Laboratory routes to highly purified N2 are seldom required. Thermal decomposition of sodium azide at 300° C under carefully controlled conditions is one possibility ... 

Sodium azide does not react with carbonyl sulfide to form 5-hydroxy-1,2,3,4-thiatriazole, nor with carboxymethyl xanthates, RO-CS SCH2COOH, to form 5-alkoxy-l,2,3,4-thiatriazoles. The latter, however, could be prepared from xanthogenhydrazides (RO-CS NHNH2) and nitrous acid. They are very unstable and may decompose explosively at room temperature only the ethoxy compound (6) has been examined in detail. This is a solid which decomposes rapidly at room temperature and even at 0°C is transformed after some months into a mixture of sulfur and triethyl isocyanurate. In ethereal solution at 20° C the decomposition takes place according to Eq. (16)... 

Incorporation of the phenethyl moiety into a carbocyclic ring was at first sight compatible with amphetamine-like activity. Clinical experience with one of these agents, tranylcypromine (79), revealed the interesting fact that this drug in fact possessed considerable activity as a monamine oxidase inhibitor and as such was useful in the treatment of depression. Decomposition of ethyl diazoacetate in the presence of styrene affords a mixture of cyclopropanes in which the trans isomer predominates. Saponification gives acid 77. Conversion to the acid chloride followed by treatment with sodium azide leads to the isocyanate, 78, via Curtius rearrangement. Saponification of 78 affords tranylcypromine (79). 

Deployed airings after a collision are filled with nitrogan gas. The gas is a byproduct of the decomposition of sodium azide, which is triggered by the collision. 

FIGURE 4.18 The rapid decomposition of sodium azide, NaN3, results in the formation of a large volume of nitrogen gas. The reaction is triggered electrically in this air bag. 

Vehicle air bags protect passengers by allowing a chemical reaction to occur that generates gas rapidly. Such a reaction must be both spontaneous and explosively fast. A common reaction is the decomposition of sodium azide, NaN , to nitrogen gas and sodium metal. 

Air can be liquefied, and liquid nitrogen boils at -195.8 °C, but liquid oxygen boils at —183 °C, so nitrogen can be vaporized first. One laboratory preparation of nitrogen is the decomposition of sodium azide, NaN3. 

The reaction of Curtius, which is especially to be preferred in the case of the higher members on account of the favourable solubilities of the intermediate products, involves as its first stage the preparation of the hydrazide from an ester (or acid chloride). The hydrazide is then converted, usually very readily, by the action of nitrous acid into the azide. In many cases it is more convenient to prepare the azide by treating an acid chloride with sodium azide previously activated with hydrazine hydrate.1 Azides easily undergo thermal decomposition, the two azo nitrogen atoms being eliminated as elementary nitrogen. In this way, however, the same radicle is formed as was invoked above to explain the Hofmann reaction ... 

Aryl sulfinyl azides, ArS(0)N3, can be prepared at low temperature by reaction of sulfinyl chloride ArS(0)Cl with sodium azide (Maricich and Hoffman, 1974). On warming to 0° they decompose with evolution of nitrogen, their decomposition exhibiting clean first-order kinetics ( = 3 x 10-4 s-1 for PhS(0)N3 in acetonitrile at 0°). The rate-determining step of the decomposition is loss of nitrogen from the sulfinyl azide to form the sulfinyl nitrene ArS(0)N (143). The subsequent behavior of this nitrene suggests (Maricich and... 

Although anation and aquation rates of vitamin B12 are not affected appreciably by aqueous micelles, the solubilized water in reversed micelles, in contrast, influences the rate and equilibrium constants for the formation and decomposition of glycine, imidazole, and sodium azide adducts of vitamin Bl2 (Fendler et al., 1974). A vitamin B12 molecule is conceivably shielded from the apolar solvent (benzene) by some 300 surfactant molecules. 

IXacing cars, such as the one shown helow, can reach speeds that are well above 200 km/h. In contrast, the maximum speed of many farm tractors is only about 25 km/h. Just as some vehicles travel more quickly than others, some chemical reactions occur more quickly than others. For example, compare the two reactions that occur in vehicles the decomposition of sodium azide in an air bag and the rusting of iron in steel. 

Tissue electrodes [2, 3, 4, 5, 45,57], In these biosensors, a thin layer of tissue is attached to the internal sensor. The enzymic reactions taking place in the tissue liberate products sensed by the internal sensor. In the glutamine electrode [5, 45], a thick layer (about 0.05 mm) of porcine liver is used and in the adenosine-5 -monophosphate electrode [4], a layer of rabbit muscle tissue. In both cases, the ammonia gas probe is the indicator electrode. Various types of enzyme, bacterial and tissue electrodes were compared [2]. In an adenosine electrode a mixture of cells obtained from the outer (mucosal) side of a mouse small intestine was used [3j. The stability of all these electrodes increases in the presence of sodium azide in the solution that prevents bacterial decomposition of the tissue. In an electrode specific for the antidiuretic hormone [57], toad bladder is placed over the membrane of a sodium-sensitive glass electrode. In the presence of the antidiuretic hormone, sodium ions are transported through the bladder and the sodium electrode response depends on the hormone concentration. 

Yields of hindered esters formed by HERON decomposition of the 1-acyl-l-alkoxy-diazene intermediates from treatment of A-alkoxy-Al-chloroamides with sodium azide in aqueous acetonitrile according to Scheme 16 are presented in Table 3 (Section III.C.4). 

Sodium azide is a toxic as well as an explosive substance (Patnaik, P. 1999. A Comprehensive Guide to the Hazardous Properties of Chemical Substances, 2nd e(j New York John Wdey Sons). Although inert to shock, violent decomposition can occur when heated at 275°C. Contact of solid or solution with lead and copper must be avoided. Reactions with halogens, carbon disulfide, or chromyl chloride can be explosive. Dissolution in water produces toxic vapors of hydrazoic acid. The salt is an acute poison causing headache, hypotension, hypothermia, and convulsion. 

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. 

The explosive properties of sodium, calcium, strontium and barium azides have been investigated at the Chemisch-Technische Reichsanstalt [135]. These azides differ markedly from lead, silver and cupric azides in that they show none of the properties of primary explosives. All three may be ignited by a spark, a glowing wire or the flame of blackpowder. Calcium azide bums most rapidly and has distinctly marked explosive properties. Larger quantities of it may explode when ignited in a closed tin, while strontium and barium merely bum violently. Calcium azide detonates under the influence of a detonating cap. The sodium azide does not decompose in these conditions. The other azides show weak decomposition under the influence of a standard (No. 3) detonator. Their most important properties are tabulated below. 

Watch the Airbags movie eChapter 8.13) and determine the signs of AH, AS, and AG for the decomposition of sodium azide. Could the decomposition of sodium azide be used to inflate airbags if the reaction were endothermic Explain. 

Most gas calculations are just applications of the ideal gas law in which three of the variables P, V, T, and n are known, and the fourth variable must be calculated. For example, the reaction used in the deployment of automobile air bags is the high-temperature decomposition of sodium azide, NaN3, to produce N2 gas. (The sodium is then removed by a subsequent reaction.) How many liters of N2 at 1.15 atm and 30°C are produced by decomposition of 145 g of NaN3 ... 

Automobile air bags are inflated with N2 gas produced by decomposition of sodium azide. 

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