Description
Nitromethane (75-52-5) is an explosive material that was
originally manufactured for various applications including
mining, construction, demolition, law enforcement, and
military uses. However, due to threats of terrorism and
increased attention to accident prevention, regulations concerning
the transportation, storage, use, and transfer relating to
explosives have steadily increased over the last few years and
manufacturing limited.
Chemical Properties
Nitromethane is explosive and can be detonated by shock or heat (HSDB 1988)
and the chemical can be made more sensitive to detonation through the presence of
other chemicals, especially amines and acids. Nitromethane forms salts with
inorganic bases and the dry salts are explosive.
Chemical Properties
Nitromethane is a highly flammable and explosive colorless liquid with a strong, disagreeable odor. Nitromethane is not explosive, but is used as industrial chemical for various purposes. Nitromethane can explode only in big quantity and in strong confinement. In combination with some further components, nitromethane is the important part of very strong, cap sensitive explosives. Therefore, nitromethane is an easy accessible precursor for preparation of strong home-made explosives.
Nitromethane is used as a stabilizer of halogenated organic solvents, rocket and racing fuel and a chemical intermediate. It is also used as a solvent for cyanoacrylate adhesives, polymers and waxes. It serves as a Michael donor, adding to alfa,beta-unsaturated carbonyl compounds through 1,4-addition in the Michael reaction. It acts as a solvent used for extractions, reaction medium and as a cleaning solvent. Further, it is used in the manufacture of pharmaceuticals, explosives, fibers and coatings.
Physical properties
Colorless liquid with a strong, disagreeable odor. Odor threshold concentration is 3.5 ppm
(quoted, Amoore and Hautala, 1983).
Uses
Solvent; chemical synthesis; fuel for
professional and model racing cars; in explosive
mixtures
Uses
Most of the nitromethane produced in the United States (85% to 90%) is used in the synthesis of nitromethane derivatives used as pharmaceuticals, agricultural soil fumigants, and industrial antimicrobials (Markofsky 1991, Angus 2001). Nitromethane also is used as a fuel or fuel additive with methanol in racing cars, boats, and model engines. 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 (NTP 1997, IARC 2000, Angus 2001).
Uses
Rocket fuel; solvent for zein. Used in the coating industry.
Definition
ChEBI: Nitromethane is a primary nitroalkane that is methane in which one of the hydrogens is replace by a nitro group. A polar solvent (b.p. 101 ℃), it is an important starting material in organic synthesis. It is also used as a fuel for rockets and radio-controlled models. It has a role as an EC 4.3.1.3 (histidine ammonia-lyase) inhibitor, a polar aprotic solvent and an explosive. It is a primary nitroalkane and a volatile organic compound.
Production Methods
Nitromethane and the other important nitroparaffins are synthesized commercially
by the vapor-phase nitration of propane (Baker and Bollmeier 1978). At temperatures
of 370-450°C and pressures of 8-12 atmospheres, nitromethane, nitroethane
and 1- and 2-nitropropane are formed and then separated by distillation.
General Description
A colorless oily liquid. Flash point 95°F. May violently decompose if intensely heated when contaminated. Denser than water and slightly soluble in water. Hence sinks in water. Vapors are heavier than air. Moderately toxic. Produces toxic oxides of nitrogen during combustion.
Air & Water Reactions
Highly flammable. Slightly soluble in water.
Reactivity Profile
Nitromethane may explode if heated or strongly shocked, especially if mixed with acids, bases [Handling Chemicals Safely 1980. p.687], acetone, aluminum powder, ammonium salts in the presence of organic solvents, haloforms (chloroform, bromoform), or hydrazine in methanol. Ignites on contact with alkyl aluminum or alkyl zinc halides. Reacts violently with strong bases (potassium hydroxide, calcium hydroxide), amines (1,2-diaminoethane, hydrazine), bromine, carbon disulfide, hydrocarbons, formaldehyde, metal oxides, lithium aluminum hydride, sodium hydride, strong oxidizing agents (lithium perchlorate, nitric acid, calcium hypochlorite). Reacts with aqueous silver nitrate to form explosive silver fulminate [Bretherick, 5th ed., 1995, p. 183]. Mixtures of Nitromethane and aluminum chloride may explode when organic matter is present [Chem. Eng. News 26:2257. 1948]. Nitromethane, either alone or in a mixture with methanol and castor oil, has a delayed but violent reaction with powdered calcium hypochlorite [Haz. Home Chem 1963]. Nitromethane reacts violently with hexamethylbenzene [Lewis 2544]. Nitromethane is strongly sensitized by hydrazine [Forshey, D. RR. et al, Explosivestoffe, 1969, 17(6), 125-129].
Hazard
Dangerous fire and explosion risk, lower
explosion limit 7.3% in air. Toxic by ingestion and
inhalation. Thyroid effects, upper respiratory tract
irritant, and lung damage. Possible carcinogen.
Health Hazard
Nitromethane is used primarily as a chemical intermediate in the synthesis of biocides, chemicals, and agricultural products and intermediates. It is slightly toxic to aquatic organisms, has a low bioconcentration potential, and is considered not readily biodegradable. Acute toxicity is low following oral or dermal exposure. Nitromethane is a mild eye irritant and is not likely to cause significant irritation to the skin. Long-term excessive exposure may cause central nervous system effects. Based on animal data, nitromethane is classified as a Category 2B carcinogen (potential human carcinogen).
Health Hazard
Nitromethane is mildly irritating to the skin and mucous membranes (Gosselin et
al 1976). It produces narcosis, mucus membrane irritation and central nervous
system excitation, and some liver damage. These effects are generally not as
marked as after administration of nitroethane. One case of human poisoning has
been reported (Kaiffer et al 1972). In that case, a handyman was exposed to high
concentrations of nitrocellulose and nitromethane resulting in a 67% conversion of
his hemoglobin to methemoglobin and sulfhemoglobin. Treatment with hyperbaric
oxygen, transfusion, peritoneal dialysis and then 6 sessions of hemodialysis
resulted in recovery.
Fire Hazard
Behavior in Fire: Containers may explode
Industrial uses
Nitromethane is used as an intermediate in chemical syntheses, but more importantly
it is used as a solvent for coatings and inks. It and the other nitroparaffins are
excellent solvents for vinyls, epoxies, polyamides and acrylic polymers (Baker
and Bollmeier 1978). It also is used as a military propellant and a racing fuel
additive (HSDB 1988). Mixed with methanol and castor oil it is employed as a
model airplane fuel.
Safety Profile
Poison by ingestion and
intraperitoneal routes. Moderately toxic by
intravenous route. Mildly toxic by
inhalation. In humans it may cause anorexia,
nausea, vomiting, darrhea, kidney injury,
and liver damage.
exposed to heat, oxidizers, or flame. May
explode by detonation, heat, or shock. Its
sensitivity is increased when mixed with
acids, bases, acetone, aluminum powder,
ammonium salts + organic solvents, bis(2-
aminoethyl)amine, 1,2-daminoethane +
N,2,4,6-tetranitro-N-methyl aniLtne,
halo forms (e.g., chloroform, bromoform),
hydrazine + methanol. Ignites when mixed
with alkyl metal halides (e.g., diethylaluminum
bromide, dimethylaluminum bromide,
ethylaluminum bromide iodide, methyl zinc
iodide, methylaluminum diiodide). Can react
violently with AlCl3 + organic matter,
Ca(OH)2, m-methyl aniline, Ca(OCl)2,
hexamethylbenzene, hydrocarbons,
inorganic bases, hydroxides, organic amines,
KOH, formaldehyde, nitric acid, metal
oxides, 1,2-diaminomethane, litlvum
perchlorate, sodium hydride. Reacts with
aqueous silver nitrate to form the explosive
silver fuhnate. When heated to
decomposition it emits toxic fumes of NOx.
See also NITROALKANES.
A very dangerous fire hazard when
exposed to heat, oxidizers, or flame. May
explode by detonation, heat, or shock. Its
sensitivity is increased when mixed with
acids, bases, acetone, aluminum powder,
ammonium salts + organic solvents, bis(2-
aminoethyl)amine, 1,2-daminoethane +
N,2,4,6-tetranitro-N-methyl aniLtne,
halo forms (e.g., chloroform, bromoform),
hydrazine + methanol. Ignites when mixed
with alkyl metal halides (e.g., diethylaluminum
bromide, dimethylaluminum bromide,
ethylaluminum bromide iodide, methyl zinc
iodide, methylaluminum diiodide). Can react
violently with AlCl3 + organic matter,
Ca(OH)2, m-methyl aniline, Ca(OCl)2,
hexamethylbenzene, hydrocarbons,
inorganic bases, hydroxides, organic amines,
KOH, formaldehyde, nitric acid, metal
oxides, 1,2-diaminomethane, litlvum
perchlorate, sodium hydride. Reacts with
aqueous silver nitrate to form the explosive
silver fuhnate. When heated to
decomposition it emits toxic fumes of NOx.
See also NITROALKANES. concentrated sulfuric acid. When heated to
decomposition it emits toxic fumes of NOx.
See also NITRO COMPOUNDS and
AMINES.
Potential Exposure
Nitromethane is used in the production
of the fumigant, chloropicrin. It is best known as racing car
fuel. It is also used as a solvent and as an intermediate in
the pharmaceutical industry.
Carcinogenicity
Nitromethane is reasonably anticipated to be a human carcinogenbased on sufficient evidence of carcinogenicity from studies in experimental animals.
Environmental Fate
Chemical/Physical. Nitromethane will not hydrolyze because it does not contain a hydrolyzable
functional group.
Metabolism
Nitromethane is converted to nitrite and formaldehyde in a 1:1 ratio by hepatic
microsomes from phenobarbital-pretreated male Sprague-Dawley rats (Sakurai et
al 1980), but no formaldehyde could be detected when microsomes from the nose
or liver of untreated male Fischer-344 rats were incubated with nitromethane
(Dahl and Hadley 1983). Whether a similar conversion occurs in vivo has not been
determined, but the absence of nitromethane metabolism in microsomes from
untreated rats suggests that its metabolism in vivo may be slow.
Shipping
UN1261 Nitromethane, Hazard Class: 3; Labels:
3-Flammable liquid.
Purification Methods
Nitromethane is generally manufactured by gas-phase nitration of methane. The usual impurities include aldehydes, nitroethane, water and small amounts of alcohols. Most of these can be removed by drying with CaCl2 or by distillation to remove the water/nitromethane azeotrope, followed by drying with CaSO4. Phosphorus pentoxide is not suitable as a drying agent. [Wright et al. J Chem Soc 199 1936.] The purified material should be stored by dark bottles, away from strong light, in a cool place. Purifications using extraction are commonly used. For example, Van Looy and Hammett [J Am Chem Soc 81 3872 1959] mixed about 150mL of conc H2SO4 with 1L of nitromethane and allowed it to stand for 1 or 2days. The solvent was washed with water, aqueous Na2CO3, and again with water, then dried for several days with MgSO4, filtered again with CaSO4. It was fractionally distilled before use. Smith, Fainberg and Winstein [J Am Chem Soc 83 618 1961] washed it successively with aqueous NaHCO3, aqueous NaHSO3, water, 5% H2SO4, water and dilute NaHCO3. The solvent was dried with CaSO4, then percolated through a column of Linde type 4A molecular sieves, followed by distillation from some of this material (in powdered form). Buffagni and Dunn [J Chem Soc 5105 1961] refluxed it for 24hours with activated charcoal while bubbling a stream of nitrogen through the liquid. The suspension was filtered, dried (Na2SO4) and distilled, then passed through an alumina column and redistilled. It has also been refluxed over CaH2, distilled and kept under argon over 4A molecular sieves. It has been purified by zone melting at low temperature, or by distillation under vacuum at 0o, subjecting the middle fraction to several freeze-pump-thaw cycles. An impure sample containing higher nitroalkanes and traces of cyanoalkanes was purified (on the basis of its NMR spectrum) by crystallisation from diethyl ether at -60o (cooling in Dry-ice)[Parrett & Sun J Chem Educ 54 448 1977]. Fractional crystallisation is more effective than fractional distillation from Drierite in purifying nitromethane for conductivity measurements. [Coetzee & Cunningham J Am Chem Soc 87 2529 1965.] Specific conductivities around 5 x 10-9 ohm-1cm-1 were obtained. [Beilstein 1 IV 100.]
Toxicity evaluation
Nitromethane affects the central nervous system (CNS) via
narcosis as a solvent. It is also a mild pulmonary irritant.
In addition, nitromethane produces histidinemia in rats by
decreasing hepatic histidase activity, leading to increased tissue
levels of histidine.
Incompatibilities
May explode from heat, shock, friction,
or concussion. Reacts with alkalis, strong acids; metallic
oxides. Detonates or reacts violently with strong oxidizers,
strong reducing agents such as hydrides; formaldehyde,
copper, copper alloys; lead, lead alloys; hydrocarbons and
other combustibles, causing fire and explosion hazard.
Forms shock sensitive mixture when contaminated with
acids, amines, bases, metal oxides; hydrocarbons, and other
combustible materials.
Waste Disposal
Incineration: large quantities
of material may require nitrogen oxide removal by catalytic
or scrubbing processes.
