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Introduction
Published in J. F. Griffiths, J. A. Barnard, Flame and Combustion, 2019
J. F. Griffiths, J. A. Barnard
In specialist applications, especially where extremely high energy liberation and also high density of the fuel are essential, the oxidant may not be air, it may not even be oxygen, it may not be in the gaseous phase, or it may not be molecularly separated from the fuel. The class of substances that fall within these categories are high explosives for commercial or military use, or low-order explosives that are used in propellants for armaments and rocketry. In high explosives the maximum amount of energy is liberated in a minimum time, as is characteristic of detonations. Typical materials are the nitrate esters, such as trinitrotoluene (TNT), nitroglycerine (NG), or nitrocellulose (NC). The oxidisers are the fuel-bound nitrogen and oxygen in these compounds. Nitrogen and oxygen also feature in a common commercial, blasting explosive, ANFO. This comprises a mixture of ammonium nitrate, the oxidiser, and fuel oil. Subject to certain criteria being satisfied, the practical qualities of ANFO include the inherent safety of being able to mix the ingredients ‘on site’ and to be able to pump the slurry into bore holes.
Propellants
Published in John A. Conkling, Christopher J. Mocella, Chemistry of Pyrotechnics, 2019
John A. Conkling, Christopher J. Mocella
The late 19th century saw the development of a new family of “smokeless” powders, as modern organic chemistry blossomed and the nitration reaction (formation of a nitrate “ester” between the hydroxyl group of an alcohol and nitric acid) became commercially feasible to chemists around the world. Two nitrate esters—nitrocellulose (NC) and nitroglycerin (NG)—became the major components of these new propellants (as well as components in new explosive formulations). Figure 9.1 illustrates the formation of NC and NG from nitric acid and the precursor alcohols cellulose and glycerin.
Additives for Crankcase Lubricant Applications
Published in Leslie R. Rudnick, Lubricant Additives, 2017
Ewa A. Bardasz, Gordon D. Lamb
Radical formation: RH+O2→ROOHHydroperoxidesROOH→RO•+•OHROH+NOx→R•+HNOx+1•2R•+O2+2NOx→RONO+RONO2Nitriteandnitrateesters Nitrogen oxides can react with alcohols (an oxidation product) to form alkyl free radicals, which react with NOx and oxygen to form nitrate and nitrate ester oxidation products.
Right on target: using plants and microbes to remediate explosives
Published in International Journal of Phytoremediation, 2019
Elizabeth L. Rylott, Neil C. Bruce
An additional class of explosives, nitrate esters, contain NO2 groups bonded to an oxygen atom attached to an aliphatic carbon and include pentaerythritol tetranitrate (PETN), glyceryl trinitrate (GTN; nitroglycerin), and ethylene glycol dinitrates (EGDN). The GTN is used by the military in munition propellants, and more widely by construction, demolition, and mining industries, EGDN is used to reduce the freezing temperature of the nitroglycerin component of dynamite. PETN is used in plastic explosives such as Semtex. PETN is toxic to plants and animals (Hawari 2014), and the medical use of GTN as a vasodilator in humans demonstrates it has biological activity. These nitrate esters also persist in the environment, and often as co-pollutants with explosives such as TNT (Arbeli et al. 2016). Although nitrate ester detoxification pathways have been described for bacteria, fungi and plants, along with some remediation studies (Rylott, Lorenz, et al. 2011), there has been little progress in bioremediation strategies in the last decade.