Нитрометан

Описание

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.

Химические свойства

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.

Физические свойства

Colorless liquid with a strong, disagreeable odor. Odor threshold concentration is 3.5 ppm (quoted, Amoore and Hautala, 1983).

Использование

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).

Методы производства

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.

Общее описание

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.

Реакции воздуха и воды

Highly flammable. Slightly soluble in water.

Профиль реактивности

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].

Опасность

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.

Угроза здоровью

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).

Пожароопасность

Behavior in Fire: Containers may explode

Промышленное использование

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.

Возможный контакт

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.

Канцерогенность

Nitromethane is reasonably anticipated to be a human carcinogenbased on sufficient evidence of carcinogenicity from studies in experimental animals.

Экологическая судьба

Chemical/Physical. Nitromethane will not hydrolyze because it does not contain a hydrolyzable functional group.

Метаболизм

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.

Перевозки

UN1261 Nitromethane, Hazard Class: 3; Labels: 3-Flammable liquid.

Несовместимости

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.

Утилизация отходов

Incineration: large quantities of material may require nitrogen oxide removal by catalytic or scrubbing processes.