Methylammonium nitrate is an explosive chemical with the molecular formula CH₆N₂O₃, alternately CH₃NH₃⁺NO₃⁻. It is the

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...

formed by the neutralization of methylamine with

nitric acid Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available nitri ...

. This substance is also known as methylamine nitrate and monomethylamine nitrate, not to be confused with methyl nitramine or monomethyl nitramine. Methylammonium nitrate was first used as an explosive ingredient by the Germans during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

. It was originally called mono-methylamine nitrate, a name that has largely stuck among chemists who formulate energetic materials. Methylammonium nitrate is somewhat similar in explosive properties to

ammonium nitrate Ammonium nitrate is a chemical compound with the chemical formula . It is a white crystalline salt consisting of ions of ammonium and nitrate. It is highly soluble in water and hygroscopic as a solid, although it does not form hydrates. It is ...

(AN) which yields 85% of the power of

nitroglycerine Nitroglycerin (NG), (alternative spelling of nitroglycerine) also known as trinitroglycerin (TNG), nitro, glyceryl trinitrate (GTN), or 1,2,3-trinitroxypropane, is a dense, colorless, oily, explosive liquid most commonly produced by nitrating ...

when the ammonium nitrate is incorporated into an explosive. The addition of the carbon-containing

methyl group In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in ma ...

in methylammonium nitrate imparts better explosive properties and helps create a more favorable oxygen balance. After World War II, methylammonium nitrate was largely ignored by explosives manufacturers, in favor of less-costly ammonium nitrate. Ammonium nitrate-fuel oil mixtures (

ANFO ANFO ( ) (or AN/FO, for ammonium nitrate/fuel oil) is a widely used bulk industrial explosive. It consists of 94% porous prilled ammonium nitrate (NH4NO3) (AN), which acts as the oxidizing agent and absorbent for the fuel, and 6% number 2 fue ...

) were sufficient for most large-diameter explosives uses. Methylammonium nitrate saw a resurgence when E. I. du Pont de Nemours and Company (

DuPont DuPont de Nemours, Inc., commonly shortened to DuPont, is an American multinational chemical company first formed in 1802 by French-American chemist and industrialist Éleuthère Irénée du Pont de Nemours. The company played a major role in ...

), seeking to lower the cost of its TNT-based

Tovex Tovex (also known as Trenchrite, Seismogel, and Seismopac) is a water-gel explosive composed of ammonium nitrate and methylammonium nitrate that has several advantages over traditional dynamite, including lower toxicity and safer manufacture, tr ...

water-gel explosive A water-gel explosive is a fuel sensitized explosive mixture consisting of an aqueous ammonium nitrate solution that acts as the oxidizer. Water gels that are cap-insensitive are referred to under United States safety regulations as blasting agen ...

s, incorporated a mixture of methylammonium nitrate with ammonium nitrate which served as a basis for DuPont's water-gels manufactured under the names "Tovex Extra" and "Pourvex Extra". Methylammonium nitrate, also known as PR-M (which stands for "Potomac River—Mono-methylamine nitrate") soon was seen as the possible path toward creating a low-cost blasting agent (water gel explosives) that might replace the explosives based on nitroglycerin (dynamites). In late 1973, DuPont started to phase out dynamite and replace it with water-gels based on PR-M. However, PR-M proved to have unusual "mass effects". That is, if there was sufficient mass, under certain conditions, PR-M could explode without warning. On August 6, 1974, a tank car containing PR-M blew up in Wenatchee, Washington, rail yard, killing two and injuring 66 others.HistoryLink Essay: Burlington Northern tank-car explodes in South Wenatchee killing two people and injuring 66 on August 6, 1974
/ref> On July 4, 1976, a PR-M storage with 60,000 pounds (approximately 27,200Kg) of PR-M detonated at DuPont's Potomac River Works at Martinsburg, WV. Though there was no loss of life, there were many injuries and a substantial loss of property.

References

External links

Crystal structure of monomethylammonium nitratemethyl ammonium nitrate (PRM) accidental detonation
{dead link, date=November 2014 Explosive chemicals Nitrates Methylammonium compounds