2-Butynoic acid

  • Tetrolic acid
  • Methylpropynoic acid
  • Methylacetylenecarboxylic acid
  • 1-Propynecarboxylic acid
Formula
C4H4O2
Structure
Description
White to pale yellow powder.

Registry Numbers and Inventories.
CAS
590-93-2
EC (EINECS/ELINCS)
209-695-7
S 26 36/37/39 45
UN (DOT)
3261
Beilstein/Gmelin
1740205
Beilstein Reference
4-02-00-01690
Canada DSL/NDSL
NDSL
US TSCA
Listed
Korea ECL
Listed

Properties.
Formula
C4H4O2
Formula mass
84.07
Melting point, °C
78
Boiling point, °C
203
Vapor pressure, mmHg
0.12 (25 C)
Density
0.9641 g/cm3 (20C)
Solubility in water
Very soluble
pKa/pKb
2.57 (pKa)
Partition coefficient, pKow
0.85
Heat of vaporization
48.4 kJ/mol
Heat of combustion
-1895 kJ/mol

Hazards and Protection.
Storage
Keep container closed when not in use. Store in a cool, dry, well-ventilated area away from incompatible substances. Corrosives area.
Handling
Minimize dust generation and accumulation. Keep container tightly closed. Do not get on skin or in eyes. Do not ingest or inhale. Use with adequate ventilation. Discard contaminated shoes.
Protection
Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to minimize contact with skin.
Respirators
A respiratory protection program that meets OSHA's 29 CFR 1910.134 and ANSI Z88.2 requirements or European Standard EN 149 must be followed whenever workplace conditions warrant a respirator's use.
Small spills/leaks
Vacuum or sweep up material and place into a suitable disposal container. Avoid runoff into storm sewers and ditches which lead to waterways. Clean up spills immediately, using the appropriate protective equipment. Avoid generating dusty conditions. Provide ventilation.
Stability
Stable at room temperature in closed containers under normal storage and handling conditions.
Incompatibilities
Strong oxidizing agents, strong reducing agents.
Decomposition
Carbon monoxide, irritating and toxic fumes and gases, carbon dioxide.

Fire.
Flash Point,°C
91
Fire fighting
Wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. During a fire, irritating and highly toxic gases may be generated by thermal decomposition or combustion. To extinguish fire, use carbon dioxide, dry chemical, or water fog.
Fire potential
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes.
Hazards
Contact with metals may evolve flammable hydrogen gas.
Combustion products
Fire may produce irritating, corrosive and/or toxic gases.
Health
3
 
Flammability
0
 
 
Reactivity
0
 

Health.
Exposure effects
   Ingestion
May cause severe and permanent damage to the digestive tract. Causes gastrointestinal tract burns.
   Inhalation
Causes chemical burns to the respiratory tract.
   Skin
Causes skin burns.
   Eyes
Causes eye burns.

First aid
 
   Ingestion
Do NOT induce vomiting. If victim is conscious and alert, give 2-4 cupfuls of milk or water. Never give anything by mouth to an unconscious person. Get medical aid immediately.
   Inhalation
Get medical aid immediately. Remove from exposure to fresh air immediately. If breathing is difficult, give oxygen. DO NOT use mouth-to-mouth respiration. If breathing has ceased apply artificial respiration using oxygen and a suitable mechanical device such as a bag and a mask.
   Skin
Get medical aid immediately. Immediately flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Wash clothing before reuse. Destroy contaminated shoes.
   Eyes
Get medical aid immediately. Do NOT allow victim to rub or keep eyes closed. Extensive irrigation is required (at least 30 minutes).

Transport.
UN number
3261
Response guide
Hazard class
8
Packing Group
I; II; III