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2,3-BUTANEDIONEICSC: 1168
Diacetyl
Dimethylglyoxal
Dimethyl diketone
2,3-Diketobutane
Butanedione
April 2009
CAS #: 431-03-8
UN #: 2346
EC Number: 207-069-8

  ACUTE HAZARDS PREVENTION FIRE FIGHTING
FIRE & EXPLOSION Highly flammable.  Vapour/air mixtures are explosive.  NO open flames, NO sparks and NO smoking.  Closed system, ventilation, explosion-proof electrical equipment and lighting.  Use powder, alcohol-resistant foam, water spray, carbon dioxide.  In case of fire: keep drums, etc., cool by spraying with water. 

 PREVENT GENERATION OF MISTS!  
  SYMPTOMS PREVENTION FIRST AID
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 CLASSIFICATION & 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. 

According to UN GHS Criteria

flam;flameskull;toxiccancer;health haz
DANGER
Highly flammable liquid and vapour
Harmful if swallowed
Toxic if inhaled
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 

Transportation
UN Classification
UN Hazard Class: 3; UN Pack Group: II 

STORAGE
Fireproof. Store in an area without drain or sewer access. Separated from : see Chemical Dangers. 
PACKAGING
 
2,3-BUTANEDIONE ICSC: 1168
PHYSICAL & CHEMICAL INFORMATION

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. 

Formula: CH3COCOCH3 / C4H6O2
Molecular mass: 86.1
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  


EXPOSURE & HEALTH EFFECTS

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

Effects of short-term exposure
The substance is severely 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. 

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 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. 


OCCUPATIONAL EXPOSURE LIMITS
TLV: 0.01 ppm as TWA; 0.02 ppm as STEL; A4 (not classifiable as a human carcinogen).
MAK: 0.071 mg/m3, 0.02 ppm; peak limitation category: II(1); skin absorption (H); sensitization of skin (SH); carcinogen category: 3B; pregnancy risk group: C.
EU-OEL: 0.07 mg/m3, 0.02 ppm as TWA; 0.36 mg/m3, 0.1 ppm as STEL 

ENVIRONMENT
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
  EC Classification
 

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    See Also:
       Toxicological Abbreviations