3-Methyl-2-butenoic acid

  • 3,3-Dimethylacrylic acid
  • 3-Methylcrotonic acid
  • Senecioic acid
Formula
C5H8O2
Structure
Description
Slightly yellow crystalline powder.

Registry Numbers and Inventories.
CAS
541-47-9
EC (EINECS/ELINCS)
208-782-7
S 26 36/37/39 45
RTECS
GQ5425000
RTECS class
Primary Irritant
UN (DOT)
3261
Beilstein/Gmelin
1720305
Beilstein Reference
4-02-00-01555
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
C5H8O2
Formula mass
100.11
Melting point, °C
63 - 65
Boiling point, °C
195
Vapor pressure, mmHg
0.2 (25 C)
Density
1.0062 g/cm3 (24 C)
Solubility in water
Very soluble
Surface tension
26.98 g/s2 (85 C)
Refractive index
1.4392 (25 C)
pKa/pKb
5.15 (pKa)
Partition coefficient, pKow
1.35
Heat of vaporization
47.5 kJ/mol
Heat of combustion
-2636 kJ/mol

Hazards and Protection.
Storage
Store in a tightly closed container. Store in a cool, dry, well-ventilated area away from incompatible substances.
Handling
Wash thoroughly after handling. Remove contaminated clothing and wash before reuse. Minimize dust generation and accumulation. Avoid contact with eyes, skin, and clothing. Keep container tightly closed. Avoid ingestion and inhalation. Use with adequate ventilation. Wash clothing before reuse.
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 gloves to prevent skin exposure. Clothing: Wear appropriate clothing to prevent skin exposure.
Respirators
Follow the OSHA respirator regulations found in 29CFR 1910.134 or European Standard EN 149. Always use a NIOSH or European Standard EN 149 approved respirator when necessary.
Small spills/leaks
Clean up spills immediately, using the appropriate protective equipment. Sweep up, then place into a suitable container for disposal. Avoid generating dusty conditions. Remove all sources of ignition. Provide ventilation.
Stability
Stable at room temperature in closed containers under normal storage and handling conditions.
Incompatibilities
Strong oxidizing agents.
Decomposition
Carbon monoxide, irritating and toxic fumes and gases, carbon dioxide.

Fire.
Flash Point,°C
93
Autoignition, °C
465
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. Extinguishing media: Use agent most appropriate to extinguish fire. In case of fire use water spray, dry chemical, carbon dioxide, or appropriate foam.
Health
1
 
Flammability
0
 
 
Reactivity
0
 

Health.
Exposure effects
   Ingestion
Causes gastrointestinal irritation with nausea, vomiting and diarrhea.
   Inhalation
Causes respiratory tract irritation.
   Skin
Causes skin irritation.
   Eyes
Causes eye irritation.

First aid
 
   Ingestion
Never give anything by mouth to an unconscious person. Get medical aid. Do NOT induce vomiting. If conscious and alert, rinse mouth and drink 2-4 cupfuls of milk or water.
   Inhalation
Remove from exposure to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical aid.
   Skin
Get medical aid. Flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Wash clothing before reuse.
   Eyes
Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid.

Transport.
UN number
3261
Response guide