DIAZOMETHANE

Diazomethane
(Diazirine, azimethylene)
CAS 334-88-3

CH₂ N₂

Yellow gas
bp -23 °C, mp -145 °C
Reacts with water

Musty odor (no accepted threshold value)

1.4 (air = 1.0)

150 °C; impure material explodes at lower temperature

LC_LO inhal (cat) 175 ppm (10 min)

PEL (OSHA) 0.2 ppm (0.4 mg/m³)

TLV-TWA (ACGIH) 0.2 ppm (0.4 mg/m³)

Powerful allergen with high acute toxicity; extremely unstable; may explode on contact with alkali metals, calcium sulfate (Drierite), or rough edges such as those found on ground glass.

Diazomethane vapor causes severe irritation of the skin, eyes, mucous membranes, and lungs. It is considered to be a substance with poor warning properties, and the effects of exposure may be delayed in onset. Symptoms of exposure may include headache, chest pain, cough, fever, severe asthmatic attacks, and pulmonary edema, which can be fatal. Exposure of the skin and mucous membranes to diazomethane may cause serious burns.

Diazomethane is a powerful allergen. Prolonged or repeated exposure to diazomethane can lead to sensitization of the skin and lungs, in which case asthma-like symptoms or fever may occur as the result of exposure to concentrations of diazomethane that previously caused no symptoms. Chronic exposure to diazomethane has been reported to cause cancer in experimental animals, but this substance has not been identified as a human carcinogen.

Note that diazomethane is often prepared in situ from precursors that may themselves be highly toxic and/or carcinogenic.

Pure diazomethane gas and liquid are readily flammable and can explode easily. A variety of conditions have been reported to cause explosions of diazomethane, including contact with rough surfaces such as ground-glass joints, etched or scratched flasks, and glass tubing that has not been carefully fire-polished. Direct sunlight and strong artificial light may also cause explosions of this substance. Violent reactions may occur on exposure of diazomethane to alkali metals.

Explosions may occur on exposure of diazomethane to alkali metals and calcium sulfate (Drierite).

Because of its high toxicity and explosibility, diazomethane should be handled using the "basic prudent practices" of Chapter 5.C, supplemented by the additional precautions for work with compounds of high chronic toxicity (Chapter 5.D) and for work with reactive and explosive substances (Chapter 5.G). In particular, diazomethane should preferably be handled in solution using glassware specially designated for diazomethane (e.g., with Clear-Seal joints) and should be used as soon as possible after preparation. Storage of diazomethane solutions (even at low temperature) is not advisable. All work with diazomethane should be conducted in a fume hood behind a safety shield, and appropriate impermeable gloves, protective clothing, and safety goggles should be worn at all times.

In the event of skin contact, immediately wash with soap and water and remove contaminated clothing. In case of eye contact, promptly wash with copious amounts of water for 15 min (lifting upper and lower lids occasionally) and obtain medical attention. If this compound is inhaled, move the person to fresh air and seek medical attention at once.

In the event of a spill, remove all ignition sources and close off the hood. Diazomethane solutions can be soaked up with a spill pillow or an absorbent material such as clay or vermiculite, placed in an appropriate container, and disposed of properly. Respiratory protection may be necessary in the event of a large spill or release in a confined area.

Small amounts of excess diazomethane can be destroyed by carefully adding acetic acid dropwise to a dilute solution of the diazomethane in an inert solvent such as ether at 0 °C. Excess diazomethane solutions and waste material containing this substance should be placed in an appropriate container, clearly labeled, and handled according to your institution's waste disposal guidelines.

The information in this LCSS has been compiled by a committee of the National Research Council from literature sources and Material Safety Data Sheets and is believed to be accurate as of July 1994. This summary is intended for use by trained laboratory personnel in conjunction with the NRC report Prudent Practices in the Laboratory: Handling and Disposal of Chemicals. This LCSS presents a concise summary of safety information that should be adequate for most laboratory uses of the title substance, but in some cases it may be advisable to consult more comprehensive references. This information should not be used as a guide to the nonlaboratory use of this chemical.

Copyright 1995 National Academy of Sciences. All rights reserved.