Ammonium perchlorate
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Ammonium perchlorate ("AP") is an inorganic compound with the formula Template:Chem2. It is a colorless or white solid that is soluble in water. It is a powerful oxidizer. Combined with a fuel, it can be used as a rocket propellant called ammonium perchlorate composite propellant. Its instability has involved it in accidents such as the PEPCON disaster.
Production
Ammonium perchlorate (AP) is produced by reaction between ammonia and perchloric acid. This process is the main outlet for the industrial production of perchloric acid. The salt also can be produced by salt metathesis reaction of ammonium salts with sodium perchlorate. This process exploits the relatively low solubility of Template:Chem2, which is about 10% of that for sodium perchlorate.[1]
AP crystallises as colorless rhombohedra.
Decomposition
Like most ammonium salts, ammonium perchlorate decomposes before melting. Mild heating results in production of hydrogen chloride, nitrogen, oxygen, and water:
The combustion of AP is quite complex and is widely studied. AP crystals decompose before melting, even though a thin liquid layer has been observed on crystal surfaces during high-pressure combustion processes.[2] Strong heating may lead to explosions. Complete reactions leave no residue. Pure crystals cannot sustain a flame below the pressure of 2 MPa.
AP is a Class 4 oxidizer (can undergo an explosive reaction) for particle sizes over 15 micrometres[3] and is classified as an explosive for particle sizes less than 15 micrometres.[4][5]
Applications
During World War I England and France used mixtures featuring ammonium perchlorate (such as "balstine") as a substitute high explosive.Script error: No such module "Unsubst".
The primary use of ammonium perchlorate is in making solid rocket propellants.[6] When AP is mixed with a fuel (like a powdered aluminium and/or with an elastomeric binder), it can generate self-sustained combustion at pressures far below atmospheric pressure. It is an important oxidizer with a decades-long history of use in solid rocket propellants – space launch (including the Space Shuttle Solid Rocket Booster), military, amateur, and hobby high-power rockets, as well as in some fireworks.Script error: No such module "Unsubst".
Some "breakable" epoxy adhesives contain suspensions of AP. Upon heating to 300°C, the AP degrades the organic adhesive, breaking the cemented joint.Script error: No such module "Unsubst".
Toxicity
Perchlorate itself confers little acute toxicity. For example, sodium perchlorate has an LD50 of 2–4g/kg and is eliminated rapidly after ingestion.[1] However, chronic exposure to perchlorates, even in low concentrations, has been shown to cause various thyroid problems, as it is taken up in place of iodine.Script error: No such module "Unsubst".
References
Further reading
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Template:Ammonium salts Template:Perchlorates
- ↑ a b Helmut Vogt, Jan Balej, John E. Bennett, Peter Wintzer, Saeed Akbar Sheikh, Patrizio Gallone "Chlorine Oxides and Chlorine Oxygen Acids" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH. Script error: No such module "doi".
- ↑ Script error: No such module "Citation/CS1".
- ↑ NFPA 400: Hazardous Materials Code, 2010
- ↑ NFPA 495: Explosive Materials Code, 2010
- ↑ "Development of an Enhanced Hazard Classification System for Oxidizers Research Project, Technical Report", Safety Engineering Laboratories, Inc., The Fire Protection Research Foundation, 13 April 2006
- ↑ "Perchlorate: Overview of Issues, Status, and Remedial Actions" Template:Webarchive, ITRC, September 2005