NIOSH Pocket Guide to Chemical Hazards

Acetic anhydride CAS 108-24-7
(CH3CO)2O RTECS AK1925000
Synonyms & Trade Names
Acetic acid anhydride, Acetic oxide, Acetyl oxide, Ethanoic anhydride
DOT ID & Guide
1715 137
Exposure
Limits
NIOSH REL: C 5 ppm (20 mg/m3)
OSHA PEL: TWA 5 ppm (20 mg/m3)
IDLH 200 ppm Conversion 1 ppm = 4.18 mg/m3
Physical Description
Colorless liquid with a strong, pungent, vinegar-like odor.
MW: 102.1
BP: 282°F
FRZ: -99°F
Sol: 12%
VP: 4 mmHg
IP: 10.00 eV

Sp.Gr: 1.08
Fl.P: 120°F
UEL: 10.3%
LEL: 2.7%

Class II Combustible Liquid: Fl.P. at or above 100F and below 140F.
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.]
Measurement Methods
NIOSH 3506; OSHA 82, 102
Personal Protection & Sanitation
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
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
See also: INTRODUCTION