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chemical explosives

Explosives

BalakumarV
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chemical explosives

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  1. INDUSTRIAL CHEMISTRY CHEMICAL EXPLOSIVES Dr. G. SANGAMI & Dr. V. BALAKUMAR Assistant Professor Department of Chemistry Sri Ramakrishna College of Arts & Science March 2023

  2. UNIT -IV CHEMICAL EXPLOSIVES An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly usually accompanied by the production of light, heat, sound, and pressure. An explosive charge is a measured quantity of explosive material, which may either be composed solely of one ingredient or be a mixture containing at least two substances.

  3. At the temperature of explosion – volume of evolved gases 15,000-20,000 times as that of explosive. • First real explosive- Gun powder or Black powder • Mixture of Sulphur-10%, Charcoal – 15% and saltpetre-75% • Nowadays- mechanical improvements have been made.

  4. GUN COTTON • Cotton consists of cellulose which cotains compound of carbon, hydrogen and oxygen. • When cellulose is allowed to react with mixture of con. nitric and sulphuric acids, various compounds of cellulose are formed – nitrocellulose. • Eg: Wood fibre or wood pulp and other vegetable fibres contains cellulose and hence they are used as source of nitrocellulose

  5. Further advance in chemistry of explosives – Alfred Noble with the discovery of Nitroglycerine in 1862. • This compound was difficult to handle on account of its sensitiveness to shock and was the cause of many fatal accidents. • Transportation and handling –great care. • Liquid nitroglycerine + Kieselguhr ---Dynamite.

  6. Most powerful explosive than dynamite was also obtained by mixing 8% nitro cotton or colloidal cotton with 92% nitroglycerine. • Resulting tough jelly like mass is called– Blasting gelatin • (Most powerful than dynamite) • Cordite- Mixing a paste of gun cotton-65% with nitroglycerie-30% and rest with acetone and vaseline.

  7. The potential energy stored in an explosive material may, for example, be chemical energy such as nitro-glycerine or grain dustpressurizedgas . • Materials that detonate (the front of the chemical reaction moves faster through the material than the speed of sound) are said to be "high explosives" and materials that deflagrate are said to be "low explosives".

  8. Explosives may also be categorized by their sensitivity. Sensitive materials that can be initiated by a relatively small amount of heat or pressure are primary explosives and materials that are relatively insensitive are secondary or tertiary explosives. A wide variety of chemicals can explode; a smaller number are manufactured specifically for the purpose of being used as explosives. The remainder are too dangerous, sensitive, toxic, expensive, unstable, or prone to decomposition or degradation over short time spans.

  9. Pb(N3)2 Formula PREPARATION AND CHEMISTRY OF LEAD AZIDE LEAD azideis still prepared by using, in principle, a method first described by Curtius. This method involves reacting a soluble inorganic azide, preferably sodium azide, with a soluble lead salt, preferably lead nitrate or lead acetate, in aqueous solution whereby lead azide is formed as a precipitate Lead(II) azide can be prepared by adding an aqueous solution of lead(II) nitrate to a solution of sodium azide. Pb(NO3)2 + 2 NaN3 → Pb(N3)2 + 2 NaNO3.

  10. Lead(II) azidePb(N3)2 is an inorganic compound. • More so than other azides, Pb(N3)2 is explosive. It is used in detonators to initiate secondary explosives. • Lead(II) azide is an initiating explosive • even a small amount can trigger an explosion caused by simple external stimuli, such as sparks, flames, friction or pinpricks, and is able to initiate the explosive reaction of rock-crushing explosives.

  11. CLASSIFICATION • 3 Fundamental types of explosives • Mechanical • Atomic • Chemical. • Our main focus is on chemical explosives • Detonating or high explosives • Deflagrating or low explosives

  12. NITROGLYCERINE Nitroglycerine is an explosive liquid which was first made by AscanioSobrero in 1846 by treating glycerol with a mixture of nitric and sulphuric acid.

  13. Nitroglycerin, also called glyceryltrinitrate, a powerful explosive and an important ingredient of most forms of dynamite. • It is also used with nitrocellulose in some propellants, especially for rockets and missiles, and it is employed as a vasodilator in the easing of cardiac pain. • Pure nitroglycerin is a colourless, oily, somewhat toxic liquid having a sweet, burning taste. 

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