Explosion, sodium azide

Alkali metal azides are not explosive, sodium azide for example decomposing at ca. 300°C to give Na and N2. Tetramethylammonium azide27 can be made in high yield and purity ... 

Particularly hazardous reagents may be charged in limiting amounts. With excess reactants present, the more hazardous reagents should be consumed. This approach is recommended for reactions with the poisonous cyanide reagents and with the explosive sodium azide. The benzyl cyanide 5 was prepared from only 1.05 equivalents of NaCN using PTC (Figure 5.3), and excess NaCN was... 

Although metal azides are known explosives, sodium azide is inert to shock. However, violent decomposition may occur when heated to 275°C (527°F). It forms lead, copper, and other metal azides, which are highly detonating when it comes in contact with the corresponding metal salts. Therefore, pouring sodium azide solution into lead or copper drain must be avoided. 

Reactivity and Incompatibility Sodium azide should not be allowed to come into contact with heavy metals or their salts, because it may react to form heavy metal azides, which are notorious shock-sensitive explosives. Do not pour sodium azide solutions into a copper or lead drain. Sodium azide reacts violently with carbon disulfide, bromine, nitric acid, dimethyl sulfate, and a number of heavy metals, including copper and lead. Reaction with water and acids liberates highly toxic hydrazoic acid, which is a dangerous explosive. Sodium azide is reported to react with CH2CI2 in the presence of DMSO to form explosive products. 

Thus, we see that from a chemical standpoint, the products of an air bag inflation are rendered safe by a series of carefully designed reactions. However, most air bags are never inflated, which means that old cars sent to scrap yards stiU contain a small amount of very toxic and explosive sodium azide. This is a recycling or disposal problem that is yet to be resolved. 

Hydrazoic acid, HN3, is a colorless, explosive liquid. It is a weak acid whose salts are called azides. Heavy-metal azides, like the acid, are unstable and are employed as detonators for explosives. Sodium azide, NaN3, is used by biochemists to study cellular respiration. The linear, symmetric azide ion, [N"=N=N] , serves as an inhibitor of the key electron transfer step. 

Hydrogen azide, HN3, and its salts (metal azides) are unstable substances used in detonators for high explosives. Sodium azide, NaNs, is used in air-bag safety systems in automobiles (see page 212). A reference source lists the following data for HN3. (The subscripts a, b, and c distinguish the three N atoms from one another.) Bond lengths Ng—Nt, = 124 pm Nb—Nc = 113 pm. Bond angles H—Na—Nb = 112.7° N —Nb—Nc = 180°. 

Sodium azide [26628-22-8] M 65.0, m 300°(dec, explosive), pK 4.72 (for HN3). Crystd from hot water or from water by the addition of absolute EtOH or acetone. Also purified by repeated crystn from an aqueous solution saturated at 90° by cooling it to 10°, and adding an equal volume of EtOH. The crystals were washed with acetone and the azide dried at room temperature under vacuum for several hours in an... 

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)... 

CAUTION All azides, particularly low molecular weight acyl and alkyl azides, are explosive, and great care should be taken while preparing and handling these materials. In addition, hydrazoic acid, which is liberated from unbuffered aqueous solutions of sodium azide, is highly toxic and all operations involving its use should be carried out in an efficient fume hood. 

Far superior yields of l-(arylsulfonyl)-l//-azepines 16 are now available by a one-pot synthesis involving the action of sodium azide on an arylsulfonyl chloride under solid-liquid phase-transfer conditions which prevents the formation of acidic sulfonamides and, hence, the ring-contraction process.75 This procedure also has the advantage of avoiding the use of high pressures and the isolation and handling of the potentially explosive sulfonyl azides. 

An explosion of the same kind, but using sodium azide, NaN3, is used in air bags in automobiles (Fig. 4.18). The explosive release of nitrogen is detonated electrically when the vehicle decelerates abruptly in a collision. 

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. 

Mass effects due to some ions in salts. It is generally observed that there is a greater instability amongst compounds containing heavy atoms compared with elements in the first periods of the periodic tabie.This can be observed by analysing enthalpies of formation of ammonia, phosphine, arsine and stibine (see previous table for the last three). In the same way, it is easier to handle sodium azide than lead azide, which is a primary explosive for detonators. It is exactly the same with the relatively highly stable zinc and cadmium thiocyanates and the much less stable mercury thiocyanate. 

Metallic cyanides, sodium azide and hydrogen azide form explosive mixtures with nitric acid. 

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. 

Nitrogen-diluted bromine vapour passed over silver azide or sodium azide formed bromine azide, and often caused explosions. 

Quaternary ammonium azides will displace halogens in a synthesis of alkyl azides. Dichloromethane has been used as a solvent, although this can slowly form diazido-methane which may be concentrated by distillation dining work-up, thereafter easily exploding [1]. An accident attributed to this cause is described, and acetonitrile recommended as a preferable solvent, supported polymeric azides, excess of which can be removed by filtration are also preferred in place of the tetrabutylam-monium salt [2]. A similar explosion was previously recorded when the quaternary azide was generated in situ from sodium azide and a phase transfer catalyst in a part aqueous system [3,4],... 

Dining the preparation of 2-azidoethanol from a stirred mixture of 2-bromoethanol (14.6 mol) and sodium azide (15.4 mol) heated on a steam bath, a violent explosion occurred after 100 min. The preparation had been carried out previously without mishap. The need for care in handling azides of low MW is stressed [1], Later detailed studies showed that the most probable cause of the explosion was the extraordinarily high mechanical and thermal sensitivity of the compound, with initiation by vibration from the agitator [2],... 

Addition of sodium azide to a solution of the acid in 20% oleum at 5-10°C to produce 3-amino-2,5-dinitrotoluene must be slow (0.1 g portions dining 1 h) to avoid explosion. 

The azide monomer, prepared in solution from the chlorophosphine and sodium azide, should not be isolated because it is potentially explosive. 

A solution, prepared by mixing saturated solutions of cadmium sulfate and sodium azide in a 10 ml glass tube, exploded violently several horns after preparation [1], The dry solid is extremely hazardous, exploding on heating or light friction. A violent explosion occurred with cadmium rods in contact with aqueous hydrogen azide [2], A DTA study showed a lesser thermal stability than lead azide [3], It is strongly endothermic (AH°f (s) +451 kJ/mol, 2.32 kJ/g). 

The precipitate from cerium nitrate and sodium azide is explosive. See other metal azides... 

During the preparation of this explosive liquid by interaction of sulfuryl chloride fluoride and sodium azide, traces of chlorine must be eliminated from the former to avoid detonation. The product is nearly as shock-sensitive as glyceryl nitrate and may explode on rapid heating. Solutions (25 wt%) in solvents may be handled safely. The corresponding fluoride is believed to behave similarly. 

Interaction of chromyl chloride and sodium azide to form chromyl azide is explosive in absence of a diluent. 

Dining treatment with sodium azide of an intermediate (believed to be pentaam-mineaquaruthenium(III) derived from the title compound) to produce pentaam-minedinitrogenruthenium(II) solutions, a dangerously explosive red solid may be produced. The solid, pentaammineazidoruthenium(III) will, however, decompose on standing to give the desired dinitrogen species. 

The preparation and immediate use of manganese(III) azide species generated slowly in situ by refluxing manganese(III) acetate and sodium azide in acetic acid in presence of alkene reaction substrates to prepare 1,2-diazidoalkanes avoids the need to isolate manganese(III) azide which has a high probability of explosive instability [1]. The (II) azide is known [20260-90-6], isolable, detonable and has been patented as a power source for lasers [2],... 

An explosion was experienced dining work up of an epoxide opening reaction involving acidified sodium azide in a dichloromethane/dimethyl sulfoxide solvent. The author ascribes this to diazidomethane formation from dichloromethane [1]. A second report of an analoguous accident, also attributed to diazidomethane, almost certainly involved hydrogen azide for the cold traps of a vacuum pump on a rotary evaporator were involved this implies an explosive more volatile than dichloromethane. It is recommended that halogenated solvents be not used for azide reactions [2]. 

Reaction with sodium azide even at —78°C leads to explosions attributed to fluorine azide formation. 

Ross, F. F., Water Waste Treatment, 1964, 9, 528 private comm., 1966 One of the reagents required for the determination of dissolved oxygen in polluted water is a solution of sodium azide in 50% sulfuric acid. It is important that the diluted acid should be quite cold before adding the azide, since hydrogen azide boils at 36°C and is explosive in the condensed liquid state. 

The product of interaction of sodium azide and phosphorus trichloride occasionally exploded on warming from 0°C to ambient temperature, but was examined safely in solution. The structure of the explosive product is determined as the title compound [1], rather than pentaazidophosphorane as originally reported [2], It contains some 82% of nitrogen. 

Aryl and vinyl nitriles have been prepared very efficiently from the corresponding bromides by palladium-catalyzed reactions under microwaves. This energy source has been employed for the conversion of these nitriles into aryl and vinyl tetrazoles by cycloaddition reactions with sodium azide (Scheme 9.66). The direct transformation of aryl halides to the aryl tetrazoles in a one pot procedure could be accomplished both in solution and on a solid support [115], The reactions were complete in a few minutes, a reaction time considerably shorter than those previously reported for the thermal reactions. The cydoadditions were performed with sodium azide and ammonium chloride in DMF and, although no explosion occurred in the development of this work, the authors point out the necessity of taking adequate precautions against this eventuality. 

The nucleophilic displacement of the halogen from 2,4-dinitrohalobenzenes by azide ion is catalysed by macrotricyclic ammonium salts [69], Kinetic studies indicate that the azide ion is entrapped and transported within the macrocyclic cage. The highly explosive tetra-azido-p-benzoquinone is obtained when the tetrachloro-quinone is reacted with an excess of sodium azide under phase-transfer catalytic conditions [70]. When only a twofold excess of the azide is used, the 2,5-diazido-3,6-dichloro compound is obtained. 

Although aliphatic azides can be prepared under liquidrliquid phase-transfer catalytic conditions [3-5], they are best obtained directly by the reaction of a haloalkane with sodium azide in the absence of a solvent [e.g. 6, 7]. Iodides and bromides react more readily than chlorides cyclohexyl halides tend to produce cyclohexene as a by-product. Acetonitrile and dichloromethane are the most frequently used solvents, but it should be noted that prolonged contact (>2 weeks) of the azide ion with dichloromethane can produce highly explosive products [8, 9] dibromomethane produces the explosive bisazidomethane in 60% yield after 16 days [8]. 

Sodium azide (NaN ) is an explosive salt of nitrogen that produces large quantities of gas upon its explosion. This quality has made it ideal as the chemical contained in automobile air safety bags. When triggered it explodes immediately, producing the expanding gases that fill the bag. 

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