You are at :

Product information: Methyl Ethyl Ketone (MEK)

1 - Characteristics

- Synonyms: MEETCO, butanone, 2-butanone, butan-2-one, methyl acetone, methylpropanone
 - Chemical formula: C4H8O or CH3COC2H5 · Molecular weight: 72,10 · MARPOL category: III
 - UN n°: 1193 · CAS n°: 78-93-3 · IMDG class: 3.2 · Hazard identification n°: 33
 - Appearance at ambient temperature (20°C):, colourless liquid, pleasant odour similar to acetone (DMK)
 - Relative density (water = 1): 0.81 · Relative vapour density (air = 1): 2.4
 - Melting point: -86°C · Boiling point: +79.6°C
 - Flash point: -6 to -1°C · Vapour pressure: 77.5 mm Hg (20°C)
 - Solubility in water: 353 g/L (at 10°C) / 263 g/L (at 20°C)
 - % evaporation / % dissolution: 44% / 56%


2 - Physico-chemical behaviour

- Stability: stable product.

 - In air: highly volatile, explosive mixture with air (LEL: 1.8 - UEL: 11.5% vol.), vapours heavier than air. Auto-ignition at 505-515°C.
 - In water: no reaction but very soluble.
- Reactivity with other products: may react with oxidisers, violently with oleum, chlorosulphuric, sulphuric and nitric acids, aliphatic amines...


3 - Spill response techniques

- Emergency measures:

  • Set up a 50 m radius exclusion zone
  • Stay upwind
  • Avoid depressions and ventilate before entering a confined space
  • Remove all sources of ignition, if possible: stop the leak
  • Prevent infiltration into sewer system, subsoil, confined spaces and the water body by building bunds or dykes made of earth or sand
  • Avoid touching the product and inhaling its vapours (stay upwind

Transfer/transshipment possibilities: fireproof pump, plastic storage tank (polyethylene, polypropylene, butyl).
 - Spill on platform area or quayside: evacuate 300 m strip downwind, contain then recover or leave to evaporate according to volume and feasibility.
 - Spill in water: contain spread using floating booms, recover using skimmers if the slick is more than 1 mm thick, otherwise leave to evaporate while monitoring possible sources of ignition.


4 - Risks for responders

- Response limits: major risk = extreme flammability/explosion when mixed with air, spread of heavy vapours near to the ground or water surface (then quick spreading through sewer system, harbour basin, port...).
 - Intoxication risks: 1 hour exposure limit of 100 ppm in air (290 mg/m³). Warning due to pleasant odour perceptible from 2 ppm i.e. 6 mg/m³ (according to odour sensitivity from 1 to 150 mg/m³).
 - Accidental direct contact of skin with the liquid not hazardous (temporary discoloration after 5 min contact time).
 - Choice of protective equipment: yes, self-contained breathing apparatus, full protective clothing, gloves and rubber boots.


5 - Risks for the environment

- Immediate effects: low toxicity for fish (LC50=1.3 at 8.9 g/L) but risk of production of organohalogen compounds that may be more toxic than the initial MEK, if the environment contains free halogens.

 - Persistence: rapid photochemical decomposition in air. In the ground or an aqueous environment, no bioaccumulation (rapid biodegradation, e.g. 20 mg/L will disappear in 2 to 3 days in an aerobic aqueous environment).

Last update on 11/06/2001
This site uses third-party services that can use cookies or similar technologies, to collect information for statistical purposes or to provide you with content tailored to your interests.