Sodium azide, safe handling

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. 

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. 

Reactions (2) and (3) arc necessary lo handle the toxic sodium reaction product from detonation. Set up a stoichiometric table solely in terms of NaNj (A). KNOi (B). etc., and the number of moles initially. If 150 g of. sodium azide are present in each air bag. hovs many grams of KNO and SiO must be added to make the reaction products safe in the form of alkaline silicate glass after the bag has inflated. The sodium azide is in itself toxic. How would you propose to handle all the undetonated air bags in cars piling up in the nation s junkyards. 

Sodium azide is fairly safe to handle and has many uses, while heavy-metal (e.g. lead) azides are shock-sensitive explosives used as detonators [28, 29], Perhaps the most widespread use of an azide is that of sodium azide in airbags, where thermally induced ignition releases nitrogen (for current applications of azides, consult the internet). An important use of the azide ion is the preparation of organic azides, which are important in synthesis [30]. The azide ion is linear and centrosym-metric [31],... 

Remarkably more stable in terms of safe handling are lithium and sodium azide which can be more reliably used in the laboratory since they are hard to initiate explosion by impact or friction. For most laboratory conditions, alkali metal azides are not considered as explosives. However, if ignited or when exposed to strong heat, alkali metal azides decompose rapidly with the evolution of large volumes of nitrogen gas. 

In addition, sodium azide and hydrazoic acid must be handled safely. In working with sodium azide, the salt must not come in contact with copper, lead, mercury, silver, gold, their alloys, and their compounds. All of these form sensitive explosive azides. Azide salts must not be thrown into sinks or sewers since all azide salts are highly toxic, react with acids to form explosive, toxic, and gaseous hydrazoic acid, and react with copper and lead pipes. Azides and hydrazoic acid are thought to be more toxic than cyanides and hydrogen cyanide [7a]. 

---