Diazomethane is the chemical compound with the molecular formula CH2N2. It is the simplest diazo compound. In the pure form at room temperature, it is an extremely sensitive explosive yellow gas. [fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”][1] Solutions containing undiluted and concentrated diazomethane may explode violently. It is soluble in ether and dioxane and will decompose slowly in either solvent. It will decompose more rapidly if water or alcohols are present. [2] Diazomethane has a musty odour. [3]


Uses [3]


Diazomethane is used as a methylating agent for acidic compounds such as carboxylic acids, phenols, and enols.


Environmental Effects [4]


Diazomethane’s production and use may result in its release to the environment through various waste streams. If released to air, at a vapour pressure of 3.94 x 10+3 mm Hg at 25 deg C, diazomethane will exist solely as a gas in the atmosphere. Gas-phase diazomethane will undergo rapid hydrolysis with atmospheric water vapour but may be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals at a much slower rate; the half-life for this reaction in air is estimated to be 16 days. Since diazomethane is a gas and reacts rapidly with water, volatilisation from water or soil is not relevant. Similarly, adsorption to soil/sediments, bioconcentration, and biodegradation are not expected due to the rapid rate of decomposition under environmental conditions.


Sources & Routes of Exposure


Sources of Exposure [4]


Occupational exposure to diazomethane may occur through inhalation if the gas supplied in its pure form or when it is formed in situ during organic syntheses. Dermal contact with solutions of this compound in organic solvents may also occur at workplaces where diazomethane is produced or used. The general population is not likely to be exposed to diazomethane since it is primarily used in a laboratory setting.


Routes of Exposure [5]


Diazomethane can effects the body if it is inhaled or comes into direct contact with the skin or eyes. I can also affect the body if ingested.


Health Effects [3]


Acute Effects


  • Diazomethane is a strong respiratory irritant. Acute inhalation exposure of humans to diazomethane may cause irritation of the eyes, cough, wheezing, asthmatic symptoms, pulmonary oedema, pneumonia, dizziness, weakness, headache, chest pains, fever, moderate cyanosis, malaise, tremors, liver enlargement, hypersensitivity, and shock.
  • Severe respiratory tract irritation, haemorrhagic emphysema, pulmonary oedema, and bronchopneumonia have been observed in animals acutely exposed by inhalation.
  • Acute animal tests in cats have demonstrated diazomethane to have high acute toxicity by inhalation.


Chronic Effects


  • No information is available on the chronic effects of diazomethane in humans or animals.
  • EPA has not established a Reference Concentration (RfC) or a Reference Dose (RfD) for diazomethane.


Reproductive/Developmental Effects


  • No information is available on the reproductive or developmental effects of diazomethane in humans or animals.


Cancer Risk


  • No information is available on the carcinogenic effects of diazomethane in humans.
  • Increased incidences of pulmonary adenomas have been observed in rats and mice exposed to diazomethane by inhalation and in dermally exposed mice.
  • EPA has not classified diazomethane with respect to its potential carcinogenicity.
  • The International Agency for Research on Cancer (IARC) has classified diazomethane as a Group 3, not classifiable as to its carcinogenicity to humans.


Safety [6]


First Aid Measures


  • If inhaled: If breathed in, move person into fresh air. If not breathing, give artificial respiration. Consult a physician.
  • In case of skin contact: Wash off with soap and plenty of water. Consult a physician.
  • In case of eye contact: Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.
  • If swallowed: Never give anything by mouth to an unconscious person. Rinse mouth with water. Consult a physician.


Exposure Controls & Personal Protection


Engineering Controls


  • Handle in accordance with good industrial hygiene and safety practice.
  • Wash hands before breaks and at the end of workday.
  • Use only with adequate ventilation.


Personal Protective Equipment


  • Eye/face protection: Face shield and safety glasses Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
  • Skin protection: Handle with gloves. Gloves must be inspected prior to use. Use proper glove removal technique (without touching glove’s outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands. The selected protective gloves have to satisfy the specifications of EU Directive 89/686/EEC and the standard EN 374 derived from it.
  • Body Protection: Complete suit protecting against chemicals, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
  • Respiratory protection: Where risk assessment shows air-purifying respirators are appropriate use a full-face particle respirator type N100 (US) or type P3 (EN 143) respirator cartridges as a backup to engineering controls. If the respirator is the sole means of protection, use a full-face supplied air respirator. Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).




United States [7]


OSHA: The Occupational Safety & Health Administration has set the following Permissible Exposure Limit (PEL) for diazomethane:

  • General Industry: 0.2 ppm, 0.4 mg/m3
  • Construction Industry: 0.2 ppm, 0.4 mg/m3 TWA


ACGIH: The American Conference of Governmental Industrial Hygienists has set a Threshold Limit Value (TLV) for diazomethane of 0.2 ppm, 0.34 mg/m3 TWA; Appendix A2 (Suspected Human Carcinogen)


NIOSH: The National Institute for Occupational Safety and Health has set a Recommended Exposure Limit (REL) for diazomethane of 0.2 ppm TWA


Australia [8]


Safe Work Australia: Safe Work Australia has established an 8-hour Time Weighted Average (TWA) concentration for diazomethane of 0.2ppm; 0.34mg/m3. It has also been classified Carcinogenicity Category 1B, which means that it is presumed to have a carcinogenic potential for humans.




  1. http://en.wikipedia.org/wiki/Diazomethane
  2. http://scorecard.goodguide.com/chemical-profiles/html/diazomethane.html
  3. http://www.epa.gov/ttn/atw/hlthef/diazomet.html
  4. https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?sid=10323035&viewopt=PubChem#x351
  5. http://www.cdc.gov/niosh/docs/81-123/pdfs/0182.pdf
  6. http://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=AU&language=en&productNumber=D28000&brand=ALDRICH&PageToGoToURL=http%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fproduct%2Faldrich%2Fd28000%3Flang%3Den
  7. https://www.osha.gov/dts/chemicalsampling/data/CH_231900.html
  8. http://www.safeworkaustralia.gov.au/sites/SWA/about/Publications/Documents/772/Workplace-exposure-standards-airborne-contaminants.pdf