UN Number: 1129 - CAS Number: 123-72-8

Also known as: BUTAL, BUTALDEHYDE, BUTANAL, BUTYL ALDEHYDE, BUTYRAL, 2-Butanone, 3-Butanone, Butanone, Ethyl Methyl Ketone, Mek, Methyl Acetone, Methyl-2-Propanone, Methylethyl Ketone, Methylethylketone, Butan-2-One, Methyl Ethyl Ketone
Information on chemical

Information on chemical

External resources

CAMEO Chemical Database
WISER Substance List


UN number 1129
CAS number 123-72-8
Formula C4H8O

Physical chemical data

Physical State (20°C) Liquid
Physical State (25°C) Liquid
Density (kg/m3)
803 [Kg/m³] at a temperature of 20°C
Kinematic viscosity (cSt)
0.51 [cSt] at a temperature of 20°C
0.5 [cSt] at a temperature of 25°C
Molar mass (g/mol) 72.11
Density of gas (kg/m3) 3.225
Solubility (g/L)
263000 [g/L] at a temperature of 20°C and salinity of 0‰
136000 [g/L] at a temperature of 25°C and salinity of 0‰
Boiling Point (°C) 75
Melting Point (°C) -97
Critical molar volume (m³/mol) 0.000267
Critical temperature (°C) 536.7
Critical pressure (Pa) 4207000
Surface tension (mN/m)
24.6 [mN/m] at a temperature of 20°C
23.97 [mN/m] at a temperature of 25°C
Vapour Pressure (Pa)
12300 [Pa] at a temperature of 20°C
12079 [Pa] at a temperature of 25°C
Ignition Temperature (°C) 230
Flash Point (°C) -6
Flash Point (Pensky-Martens closed cup) (°C) -2
Flash Point (Cleveland open cup) (°C) 1
Lower explosivity limit (LEL) (volume %) 2.47
Upper explosivity limit (UEL) (volume %) 10.6
Vapor enthalpy (J/Kg)
434059 [J/Kg] at a temperature of 79.6°C
482457 [J/Kg] at a temperature of 25°C
Combus enthalpy (J/Kg) 32700000
Specific heat capacity (J/(Kg·K)) 2200.8
Combustion efficiency (%) 96
Mass flow rate of the combustion surface (Kg/(m²·s)) 0.07
Rad fraction (%) 28
Henry's constant (mol/(m³·Pa)) 5.83

Behaviour at sea

Log kow 0.29
Log koc 0.55
Aqueous photolysis (Half-life) Not photolysable
Biodegradation in estuary environment (Half-life) (days) Not hydrolysable
Biodegradation in marine environment (Half-life) (days) 10
Bioconcentration factor (BCF) 0.98

Additional data

Colour colourless
Odour pungent odour
MARPOL pollution category
Category Description
Z Noxious Liquid Substances which, if discharged into the sea from tank cleaning or deballasting operations, are deemed to present a minor hazard to either marine resources or human health and therefore justify less stringent restrictions on the quality and quantity of the discharge into the marine environment.
Standard behavior classification DE

Transportation data

Transport mode Bulk,Packaged
Package group II
Cargo group 19
State liquid
Temperature (°C) ambient
Pressure (Pa) under pressure
Family name aldehydes
IMO class 3.2

Reactivity data

Water No
Acid(s) Yes
Base(s) Yes
Metal(s) and alloys No
Oxidizing agents Yes
Reducing agents No
Combustibles No
Organic substance No

GESAMP Hazard profile

Bioaccumulation in logPow (A1A) 1 - ≥1 and <2
Bioaccumulation (A1) 1 - Very low potential to bioaccumulate
Biodegradation (A2) R - Readily biodegradable
Acute aquatic toxicity (B1) (LC/EC/IC50 (mg/l)) 2 - Slightly toxic
Chronic aquatic toxicity (B2) (NOEC (mg/l)) 0 - Negligible
Acute mammalian toxicity by swallowing (C1) (LD50 (mg/kg)) 0 - Negligible
Acute mammalian toxicity by skin penetration (C2) (LD50 (mg/kg)) 1 - Slight
Acute mammalian toxicity by inhalation (C3) (LC50 (mg/l)) 0 - Negligible
Skin irritation/corrosivity (D1) 3 - Corrosive
Eye irritation/corrosivity (D2) 3 - Severely irritating, with irreversible corneal injury
Interference with coastal amenities (E2) DE - Dissolver/Evaporator
Effects on wildlife and bottom habitats (E3) 3 - Is highly acutely toxic; and/or is severely irritant or corrosive to skin or eyes; and/or is carcinogenic, mutagenic or reprotoxic; and/or is a floater or persistent floater with associated health effects

Human toxicity threshold

Flammable Harmful
IDHL 300
Hazard statements
H225 Highly flammable liquid and vapour.
H319 Causes serious eye irritation.
H336 May cause drowsiness or dizziness.
Precautionary statements
P102 Keep out of reach of children.
P210 Keep away from heat/sparks/open flames/hot surfaces. No smoking.
P233 Keep container tightly closed.
P240 Ground/bond container and receiving equipment.
P241 Use explosion-proof electrical/ventilating/lighting/.../equipment.
P242 Use only non-sparking tools.
P243 Take precautionary measures against static discharge.
P261 Avoid breathing dust/fume/gas/mist/vapours/spray.
P264 Wash ... thoroughly after handling.
P271 Use only outdoors or in a well-ventilated area.
P280 Wear protective gloves/protective clothing/eye protection/face protection.
P303 + P361 + P353 IF ON SKIN (or hair): Remove/Take off immediately all contaminated clothing. Rinse skin with water/shower.
P305 + P351 + P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
P312 Call a POISON CENTER or doctor/physician if you feel unwell.
P337 + P313 If eye irritation persists: Get medical advice/attention.
P370 + P378 In case of fire: Use ... for extinction.
P403 + P233 Store in a well-ventilated place. Keep container tightly closed.
P405 Store locked up.
P501 Dispose of contents/container to ...
TEEL-1 (mg/m3) 0.06 ppm
TEEL-2 (mg/m3) 0.4 ppm
TEEL-3 (mg/m3) 12.5 ppm


Lowest median lethal concentration (LC50) on crustacean (mg/l) 1382
Lowest median lethal concentration (LC50) on fishes (mg/l) 1656
Highest no observed effect concentration (NOEC) on fishes (mg/l) 1170
Assessment factor (AF)
1 on the Short term
Predicted No Effect Concentration (PNEC) (µg/l)
55.8 [µg/l] on the Short term
Incident reports

Incident reports

No incident reports available

Emergency Response Guidebook

Emergency Response Guidebook

Guide number: 129P

See the guide or download the emergency response guidebook

At sea emergency guide

At sea emergency guide

Emergency schedule: 2-07


Emergency procedures


Avoid all skin contact.
Avoid all sources of ignition (e.g. naked lights, unprotected light bulbs, electric handtools).

Spillage on deck

Stop leak if practicable. Let spilt liquid evaporate.

Spillage under deck

Provide adequate ventilation. Stop leak if practicable. Let spilt liquid evaporate.

Fire on deck

Use water spray, foam or dry chemical from as far away as practicable.
Keep adjacent receptacles cool with copious quantities of water. Remove undamaged cooled receptacles to a safe place.

Fire under deck

Batten down; use ship's fixed fire-fighting installation. Otherwise adopt action as for "On deck".

Special equipment to be carried

Protective gloves.
Self-contained breathing apparatus.
Spray nozzles.

Remarks by UN no.

Care! Heated receptacles should be jettisoned as possible explosion hazard.

Decision trees

Decision trees

No decision trees available

No additional data

last modified 2023-03-06T12:01:23+00:00

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