NIOSH logo and tagline

Acetic anhydride

Synonyms & Trade Names
Acetic acid anhydride, Acetic oxide, Acetyl oxide, Ethanoic anhydride
CAS No.
108-24-7
RTECS No.
DOT ID & Guide
1715 137
Formula
(CH₃CO)₂O
Conversion
1 ppm = 4.18 mg/m3
IDLH
200 ppm
See: 108247
Exposure Limits
NIOSH REL
C 5 ppm (20 mg/m3)
OSHA PEL
TWA 5 ppm (20 mg/m3) See Appendix G
Measurement Methods
NIOSH 3506;
OSHA 82 , 102
See: NMAM or OSHA Methods
Physical Description
Colorless liquid with a strong, pungent, vinegar-like odor.
Molecular Weight
102.1
Boiling Point
282°F
Freezing Point
-99°F
Solubility
12%
Vapor Pressure
4 mmHg
Ionization Potential
10.00 eV
Specific Gravity
1.08
Flash Point
120°F
Upper Explosive Limit
10.3%
Lower Explosive Limit
2.7%
Class II Combustible Liquid: Fl.P. at or above 100°F and below 140°F.
Incompatibilities & Reactivities
Water, alcohols, strong oxidizers (especially chromic acid), amines, strong caustics [Note: Corrosive to iron, steel & other metals. Reacts with water to form acetic acid.]
Exposure Routes
inhalation, ingestion, skin and/or eye contact
Symptoms
conjunctivitis, lacrimation (discharge of tears), corneal edema, opacity, photophobia (abnormal visual intolerance to light); nasal, pharyngeal irritation; cough, dyspnea (breathing difficulty), bronchitis; skin burns, vesiculation, sensitization dermatitis
Target Organs
Eyes, skin, respiratory system
Personal Protection/Sanitation
(See protection codes)
Skin:Prevent skin contact
Eyes:Prevent eye contact
Wash skin:When contaminated
Remove:When wet or contaminated
Change:No recommendation
Provide:Eyewash, Quick drench
First Aid
(See procedures)
Eye:Irrigate immediately
Skin:Water flush immediately
Breathing:Respiratory support
Swallow:Medical attention immediately
Respirator Recommendations

NIOSH/OSHA

Up to 125 ppm:
(APF = 25) Any supplied-air respirator operated in a continuous-flow mode£
(APF = 25) Any powered, air-purifying respirator with organic vapor cartridge(s)£

Up to 200 ppm:
(APF = 50) Any chemical cartridge respirator with a full facepiece and organic vapor cartridge(s)
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister
(APF = 50) Any powered, air-purifying respirator with a tight-fitting facepiece and organic vapor cartridge(s)£
(APF = 50) Any self-contained breathing apparatus with a full facepiece
(APF = 50) Any supplied-air respirator with a full facepiece

Emergency or planned entry into unknown concentrations or IDLH conditions:
(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus

Escape:
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister
Any appropriate escape-type, self-contained breathing apparatus

Important additional information about respirator selection

See also
INTRODUCTION   ICSC CARD: 0209
Page last reviewed: October 30, 2019