Lead Azide Laboratory Preparation

Redman, L.D., and Spear, R.J. (1983) Mercuric-5-Nitrotetrazole a possible replacement for lead azide in Australian ordnance. Part I an assessment of preparation methods. Materials Research Laboratory, Melbourne, Report No. MRL-R-901 Chem. Abstr., (1984) 100,194540. 

General Properties A545 to A550 Laboratory Preparation A546 Manufacture of Deztrinated Lead Azide A547... 

The reader is referred to Volume 1, Chapter 1 for details of other laboratory methods for the preparation of lead azide on a small scale, and to references [7] and [8] for the origins and details of early manufacturing processes. 

Lead azide, which is normally stored in alcohol-water, reacts with the liberation of hydrazoic acid. It is possible to detect hydrazoic acid in the vapors over lead azide immersed in alcohol-water. With other azides, such as that of barium, water can generate hydrazoic acid readily. The normal laboratory preparation of hydrazoic acid is to acidify sodium azide and distill the hydrazoic acid with an inert gas carrier. The explosion limits of this substance have not been established with any degree of assurance however, it is known that hot spots and sparks will initiate gaseous mixtures of hydrazoic acid in air [1,2]. 

USE In Organic Syntheses in the preparation of hydrazoic acid, lead azide, pure sodium. In the differential selection of bacteria in automatic blood counters as preservative for laboratory reagents. Propellant for inflating automotive safety bags. Agricultural nematocide herbicide in fruit rot control. 

Redman, L.D., Spear, R.J. Mercuric 5-Nitrotetrazole, a Possible Replacement for Lead Azide in Australian Ordnance. Part 1. An Assessment of Preparation Methods. Report MRL-R-901, Department of Defense, Material Research Laboratories, Ascot Vale, 1983... 

A method of preparing a reduced sensitivity SA introduced in USA is called the Costain process after Thomas Costain who improved the original procedure for RD 1336 developed in England in the ERDE laboratories shortly after World War 11 [96]. In the Costain process, aqueous solutions of silver nitrate and sodium azide are added to the dilute aqueous ammonia (or an aqueous solution of sodium azide is added to an aqueous solution of silver nitrate and ammonia). The reaction mixture is then heated and part of the ammonia is distilled from the solution. When the first silver azide precipitate appears, a small amount of acid (e.g., acetic acid) is added to induce crystal seeding and results in profuse nucleation ( shock crystallization ). The distillation of ammonia then continues and the precipitation of silver azide is total. Costain reported several improvements for his product, first of all bulk density 1.4 g cm [96]. Hirlinger and Bichay later reported a further improvement leading to a product with density 1.6 g cm [97] (vs. 1.0 g cm for original ERDE silver azide). Further, concentration and addition parameters are not as critical as for the ERDE process [96]. Not much has been published about the Costain process but some details have been published in [98]. 

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