Methylhydrazine

Description

Methyl hydrazine, CH3NHNH2, is a colorless, hygroscopic liquid with an ammonia-like odor. It is soluble in water, with a specific gravity of 0.87, which is lighter than water. Methyl hydrazine is toxic by inhalation and ingestion, and is a suspected human carcinogen. The TLV ceiling is 0.2 ppm in air, and the IDLH is 50 ppm. The target organs are the central nervous system, respiratory system, liver, blood, eyes, and cardiovascular system. The four-digit UN identification number is 1244. The NFPA 704 designation is health 4, flammability 3, and reactivity 2. The primary uses are as a missile propellant and a solvent.

Description

We begin 2023 with the nasty molecule methylhydrazine. As shown in the hazard information table, the compound, also called monomethylhydrazine (MMH), is deadly to humans and environmentally harmful. It is, unexpectedly, found in nature.
Methylhydrazine has been known since at least 1888, when German chemist Gustav von Brüning initiated a series of articles on the molecule. In 1890, he reported a synthesis of MMH that began with the preparation of 1-nitroso-1-methylurea from methylurea nitrate and sodium nitrite. The nitroso compound was then reduced with zinc dust in acetic acid to produce MMH after an extensive workup procedure.
In 1954, L. F. Audrieth* and L. H. Diamond at the University of Illinois (Urbana–Champaign) reported a more concise synthesis: They prepared methylhydrazine and other monosubstituted hydrazines via the reaction of methylamine with chloramine. This process is used for the modern industrial production of MMH. The compound’s main uses are in rocket propellants and the synthesis of higher hydrazine derivatives and other organic chemicals.
Where does methylhydrazine turn up in nature? It is one of the deadliest compounds in poisonous mushrooms. It is found in Gyromitra spp., in which it is formed when the native toxin gyromitrin1 hydrolyzes. Other lethal mushroom poisons include α-amanitin2, orellanine3, and ergotamine4.
1. CAS Reg. No. 16568-02-8. 2. CAS Reg. No. 23109-05-9. 3. CAS Reg. No. 37338-80-0. 4. CAS Reg. No. 113-15-5.

Chemical properties

colourless liquid with an ammonia-like odour

Chemical properties

Methyl hydrazine is a fuming, colorless liquid with an ammonia-like odor. The odor threshold is 1.3
1.7 ppm.

Physical properties

Fuming, clear, colorless liquid with an ammonia-like odor. Odor threshold concentrations ranged from 1 to 3 ppm (quoted, Keith and Walters, 1992).

The Uses of Methylhydrazine

Methylhydrazine is used in missile propellants and as a solvent and chemical intermediate.

The Uses of Methylhydrazine

Missile propellant, intermediate, solvent.

The Uses of Methylhydrazine

Rocket fuel; solvent; chemical intermediate

Production Methods

Methylhydrazine ignites spontaneously on contact with strong oxidizing agents. It is prepared commercially from the reaction of monochloroamine and monomethylamine.

Air & Water Reactions

Highly flammable. Often ignites spontaneously. Exposure to air on a large surface may result in spontaneous ignition [Def. Res. and Eng. 27. 1963]. Water soluble. Solutions are highly alkaline and generate heat when water is added.

Reactivity Profile

Methylhydrazine is a powerful reducing agent. Ignites upon contact with oxidizing agents i.e. dinitrogen tetraoxide, hydrogen peroxide [Hawley]. Water used to extinguish a fire may cause pollution and should be diked for later disposal. Gives basic solutions with water that generate heat when water is added.

Hazard

Flammable, dangerous fire risk, vapors mayexplode, may self-ignite in air and on contact withoxidizing agents. Toxic by ingestion and inhalation.Eye and upper respiratory tract irritant, lung cancerand liver damage. Possible carcinogen.

Health Hazard

Methyl hydrazine vapors are extremely toxic and the liquid is corrosive to skin. Methyl hydrazine is the strongest convulsant and the most toxic of methyl-substituted hydrazine derivatives. It is more toxic than hydrazine. At high doses, it is a strong central nervous system poison that can lead to convulsions and death. Skin rash may be aggravated by skin exposure.

Fire Hazard

Extremely flammable; ignites spontaneously under almost all normal temperature conditions. Water used to extinguish a fire may cause pollution and should be diked for later disposal. Water may be ineffective in extinguishing fires due to the chemical's low flash point. Because of the wide flammability limits, low flash point, and reignition hazard, dry chemicals, carbon dioxide, water spray, and foam may not be as effective as water dilution of fire area. The vapor is heavier than air; thus Methylhydrazine may accumulate sufficiently to flash back. Methylhydrazine fires produce irritating nitrogen oxides. Ignites spontaneously in air when in contact with porous materials (e.g., earth, asbestos, wood, or cloth). Also ignites spontaneously on contact with strong oxidizing agents (e.g., fluorine, chlorine trifluoride, fuming nitric acid, and nitrogen tetroxide). Heat or flame should be avoided because chemical is extremely flammable and explosive.

Safety Profile

Suspected carcinogen with experimental carcinogenic, neoplastigenic, tumorigenic, and teratogenic data. Poison by inhalation, ingestion, skin contact, intraperitoneal, subcutaneous, and intravenous routes. Experimental reproductive effects. Human mutation data reported. Corrosive to skin, eyes and mucous membranes. May self-ignite in air. Very dangerous fire hazard when exposed to heat or flame. To fight fire, use alcohol foam, CO2, dry chemical. Explosive in the form of vapor when exposed to heat or flame. A powerful reducing agent. It is hypergolic with many oxidants (e.g., dinitrogen tetraoxide and hydrogen peroxide). When heated to decomposition it emits toxic fumes of NOx.

Potential Exposure

MMH has been used as the propellant in liquid propellant rockets; it is also used as a solvent and as an organic intermediate.

First aid

First Aid: If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek med-First Aid: If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek med-ical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, includ-ing resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medi-cal attention. If victim is conscious, administer water ormilk. Do not induce vomiting. Medical observation isrecommended for 24- -48 h after breathing overexposure, aspulmonary edema may be delayed. As first aid for pulmo-nary edema, a doctor or authorized paramedic may consideradministering a corticosteroid spray.Note to physician:Treatfor methemoglobinemia.Spectrophotometry may be required for precise determina-tion of levels of methemoglobin in urine.

Carcinogenicity

The carcinogenicity of methylhydrazine has been extensively investigated. In two studies, no compound-related increase in tumor incidence was observed in mice treated orally with methylhydrazine . In other studies, methylhydrazine produced lung tumors in mice and malignant histiocytoma of the liver and cecal tumors in hamsters when administered in drinking water at concentrations of 0.01%. Potential carcinogenicity from vapor exposure to methylhydrazine was also investigated in rats, dogs, hamsters, and mice. Exposures to methylhydrazine at concentrations of 0.02 ppm (rats and mice only) and 0.2, 2, and 5 ppm (rats and hamsters only)were conducted for 6 h/day, 5 days/week, for a year, followed by observation for 1 year.

Source

Rocket fuel; solvent; intermediate; organic synthesis.

Environmental Fate

Biological. It was suggested that the rapid disappearance of methylhydrazine in sterile and nonsterile soil (Arrendondo fine sand) under aerobic conditions was due to chemical oxidation. Although the oxidation product was not identified, it biodegraded to carbon dioxide in the nonsterile soil. The oxidation product did not degrade in the sterile soil (Ou and Street, 1988).

storage

Color Code—Red: Flammability Hazard: Store ina flammable liquid storage area or approved cabinet awayfrom ignition sources and corrosive and reactive materials.Prior to working with this chemical you should be trainedon its proper handling and storage. Before entering confinedspace where this chemical may be present, check to makesure that an explosive concentration does not exist. Methylhydrazine must be stored to avoid contact with oxides ofiron and copper; manganese, lead, and copper alloys;porous materials (such as earth, asbestos, wood, and cloth);oxidizers (such as perchlorates, hydrogen peroxide, chlorates, nitrates, permanganates); and fuming nitric acid sinceviolent reactions occur. Store in tightly closed containers ina cool, well-ventilated area away from heat and sparks.Sources of ignition, such as smoking and open flames, areprohibited where methyl hydrazine is handled, used, orstored. Metal containers involving the transfer of 5 gallonsor more of methyl hydrazine should be grounded andbonded. Drums must be equipped with self-closing valves,pressure vacuum bungs, and flame arresters. Use only nonsparking tools and equipment, especially when opening andclosing containers of methyl hydrazine. Wherever methylhydrazine is used, handled, manufactured, or stored, useexplosion-proof electrical equipment and fittings. A regulated, marked area should be established where this chemical is handled, used, or stored in compliance with OSHAStandard 1910.1045.

Shipping

UN1244 Methylhydrazine, Hazard class: 6.1; Labels: 6.1-Poison Inhalation Hazard, 3-Flammable liquid, 8-Corrosive material, Inhalation Hazard Zone A

Purification Methods

Dry with BaO, then distil it in a vacuum. Store it under nitrogen. [Beilstein 4 IV 3322.]

Incompatibilities

May form explosive mixture with air. Methyl hydrazine is a highly reactive reducing agent and a medium strong base. May explode if heated. Violent reaction with strong oxidizers, such as fluorine, chlorine, combustibles, nitric acid; hydrogen peroxide. Incompatible with acids, alcohols, glycols, isocyanates, phenols, cresols; porous materials, such as earth, asbestos, wood and cloth. Oxides of iron or copper, manganese, lead, copper or their alloys can lead to fire and explosions. Attacks cork, some plastics, coatings and rubber.

Waste Disposal

Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform to EPA regulations governing storage, transportation, treatment, and waste disposal. There are 2 alternatives: Dilute with water, neutralize with sulfuric acid, then flush to sewer with large volumes of water or incinerate with added flammable solvent in furnace equipped with afterburner and alkaline scrubber.