The dominant use of the nitromethane is as a precursor reagent. A major derivative is
chloropicrin (), a widely used pesticide. It condenses with
formaldehyde (
Henry reaction) to eventually give
tris(hydroxymethyl)aminomethane ("tris"), a widely used buffer and ingredient in
alkyd resins. The
oxygen content of nitromethane enables it to burn with much less atmospheric oxygen than conventional fuels. During nitromethane combustion,
nitric oxide (NO) is one of the major emission products along with CO and HO. Nitric oxide contributes to air pollution, acid rain, and ozone layer depletion. Recent (2020) studies suggest the correct stoichiometric equation for the burning of nitromethane is: : The amount of air required to burn of gasoline is , but only of air is required for 1 kg of nitromethane. Since an engine's cylinder can only contain a limited amount of air on each stroke, 8.6 times as much nitromethane as gasoline can be burned in one stroke. Nitromethane, however, has a lower specific energy: gasoline provides about 42–44
MJ/kg, whereas nitromethane provides only 11.3 MJ/kg. This analysis indicates that nitromethane generates about 2.3 times the power of gasoline when combined with a given amount of oxygen. Nitromethane can also be used as a
monopropellant, i.e., a propellant that decomposes to release energy without added oxygen. It was first tested as rocket monopropellant in 1930s by from the Italian Rocket Society. There is a renewed interest in nitromethane as safer replacement of
hydrazine monopropellant. The following equation describes this process: : Nitromethane has a
laminar combustion velocity of approximately 0.5 m/s, somewhat higher than gasoline, thus making it suitable for high-speed engines. It also has a somewhat higher
flame temperature of about . The high heat of vaporization of 0.56 MJ/kg together with the high fuel flow provides significant cooling of the incoming charge (about twice that of methanol), resulting in reasonably low temperatures. Nitromethane is usually used with
rich air–fuel mixtures because it provides power even in the absence of atmospheric oxygen. When rich air–fuel mixtures are used, hydrogen and carbon monoxide are two of the combustion products. These gases often ignite, sometimes spectacularly, as the normally very rich mixtures of the still burning fuel exits the exhaust ports. Very rich mixtures are necessary to reduce the temperature of combustion chamber hot parts in order to control pre-ignition and subsequent detonation. Operational details depend on the particular mixture and engine characteristics. A small amount of
hydrazine blended in nitromethane can increase the power output even further. With nitromethane, hydrazine forms an explosive salt that is again a monopropellant. This unstable mixture poses a severe safety hazard. The
National Hot Rod Association and
Academy of Model Aeronautics do not permit its use in competitions. In
model aircraft and
car glow fuel, the primary ingredient is generally
methanol with some nitromethane (0% to 65%, but rarely over 30%, and 10–20% lubricants (usually
castor oil and/or
synthetic oil)). Even moderate amounts of nitromethane tend to increase the power created by the engine (as the limiting factor is often the air intake), making the engine easier to tune (adjust for the proper air/fuel ratio).
Former uses It formerly was used in the explosives industry as a component in a binary explosive formulation with ammonium nitrate and in shaped charges, and it was used as a chemical stabilizer to prevent decomposition of various halogenated hydrocarbons.
Other It can be used as an explosive, when gelled with several percent of gelling agent. This type of mixture is called
PLX. Other mixtures include ANNM and ANNMAl – explosive mixtures of ammonium nitrate, nitromethane and
aluminium powder. ==Reactions==