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2,3-BUTANEDIONE
ICSC: 1168
Peer-Review Status: 01.04.2009 Validated
Diacetyl
Dimethylglyoxal
Dimethyl diketone
2,3-Diketobutane
Butanedione 
CAS #: 431-03-8 RTECS #: EK2625000
UN #: 2346
EINECS #: 207-069-8
    Formula: CH3COCOCH3 / C4H6O2
Molecular mass: 86.1

TYPES OF
HAZARD /
EXPOSURE
ACUTE HAZARDS / SYMPTOMS      PREVENTION      FIRST AID / FIRE FIGHTING
FIRE Highly flammable.  NO open flames, NO sparks and NO smoking.  Use powder, alcohol-resistant foam, water spray, carbon dioxide. 
EXPLOSION Vapour/air mixtures are explosive.  Closed system, ventilation, explosion-proof electrical equipment and lighting.  In case of fire: keep drums, etc., cool by spraying with water. 
 
EXPOSURE   PREVENT GENERATION OF MISTS!   
Inhalation Cough. Drowsiness. Nausea. Headache. Sore throat.  Use ventilation, local exhaust or breathing protection.  Fresh air, rest. Refer for medical attention. 
Skin Redness.  Protective gloves. Protective clothing.  Remove contaminated clothes. Rinse skin with plenty of water or shower. 
Eyes Redness. Pain. Burns.  Wear safety goggles or eye protection in combination with breathing protection.  First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention. 
Ingestion Sore throat.  Do not eat, drink, or smoke during work.  Rinse mouth. Give one or two glasses of water to drink. Seek medical attention if you feel unwell. 

SPILLAGE DISPOSAL
PACKAGING & LABELLING
Remove all ignition sources. Personal protection: filter respirator for organic gases and vapours adapted to the airborne concentration of the substance. Do NOT let this chemical enter the environment. Collect leaking liquid in covered containers. Absorb remaining liquid in sand or inert absorbent. Then store and dispose of according to local regulations.   
EC Classification
 
UN Classification
UN Hazard Class: 3; UN Pack Group: II 
GHS Classification
Signal: Danger
Highly flammable liquid and vapour
Harmful if swallowed
Toxic if inhaled (vapour)
Causes skin irritation
Causes serious eye irritation
Causes damage to respiratory system if inhaled
Causes damage to respiratory system through prolonged or repeated exposure if inhaled
Harmful to aquatic life 
flam;flameskull;toxiccancer;health haz

EMERGENCY RESPONSE SAFE STORAGE
NFPA Code: H2; F3; R0.  Fireproof. Store in an area without drain or sewer access. Separated from : see Chemical Dangers. 

IMPORTANT DATA
Physical State; Appearance
GREEN-TO-YELLOW LIQUID. 

Physical dangers
The vapour is heavier than air and may travel along the ground; distant ignition possible. 

Chemical dangers
Heating may cause violent combustion or explosion. Reacts violently with strong acids, strong bases and oxidants. 

Occupational exposure limits
TLV not established.
MAK (not established):. 

Routes of exposure
The substance can be absorbed into the body by inhalation and by ingestion. 

Inhalation risk
No indication can be given about the rate at which a harmful concentration of this substance in the air is reached on evaporation at 20°C. 

Effects of short-term exposure
The substance is irritating to the eyes. The substance is irritating to the skin and respiratory tract. The substance may cause effects on the central nervous system, lungs and respiratory tract. Exposure at high levels could cause lowering of consciousness. 

Effects of long-term or repeated exposure
Lungs may be affected by repeated or prolongated exposure to the vapour. This may result in impaired functions. See Notes. 


PHYSICAL PROPERTIES ENVIRONMENTAL DATA
Boiling point: 88°C
Melting point: -2.4°C
Relative density (water = 1): 1.1
Solubility in water, g/100ml at 25°C: 20
Vapour pressure, kPa at 25°C: 7.6
Relative vapour density (air = 1): 3
Relative density of the vapour/air-mixture at 20°C (air = 1): 0.99
Flash point: 6°C c.c.
Auto-ignition temperature: 365°C
Explosive limits, vol% in air: 2.4-13
Octanol/water partition coefficient as log Pow: -1.34  
The substance is harmful to aquatic organisms. 

NOTES
Irreversible obstructive lung disease has been documented among workers exposed in a variety of settings. These include 2,3-butanedione (diacetyl) production in the chemical industry, production of 2,3-butanedione (diacetyl)-containing flavorings, and production of diacetyl-containing, butter-flavored food products such as microwave popcorn. Many cases have been confirmed to have severe clinical bronchiolitis obliterans.
Environmental effects from the substance have not been investigated adequately.
Do NOT take working clothes home. 

ADDITIONAL INFORMATION
 

IPCS
International
Programme on
Chemical Safety
WHO ILO EC Prepared in the context of cooperation between the International Programme on Chemical Safety and the European Commission
© IPCS 2004-2012
LEGAL NOTICE Neither the EC nor the IPCS nor any person acting on behalf of the EC or the IPCS is responsible for the use which might be made of this information.
    See Also:
       Toxicological Abbreviations