Acetic anhydride

Acetic anhydride
Acetic anhydride
Acetic anhydride
Names
Preferred IUPAC name
Acetic anhydride
Systematic IUPAC name
Ethanoic anhydride
Other names
Ethanoyl ethanoate
Acetic acid anhydride
Acetyl acetate
Acetyl oxide
Acetic oxide
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.003.241 Edit this at Wikidata
EC Number
  • 203-564-8
RTECS number
  • AK1925000
UNII
UN number 1715
  • InChI=1S/C4H6O3/c1-3(5)7-4(2)6/h1-2H3 checkY
    Key: WFDIJRYMOXRFFG-UHFFFAOYSA-N checkY
  • InChI=1/C4H6O3/c1-3(5)7-4(2)6/h1-2H3
    Key: WFDIJRYMOXRFFG-UHFFFAOYAH
  • O=C(OC(=O)C)C
  • CC(=O)OC(=O)C
Properties
C4H6O3
Molar mass 102.089 g·mol−1
Appearance colorless liquid
Density 1.082 g cm−3, liquid
Melting point −73.1 °C (−99.6 °F; 200.1 K)
Boiling point 139.8 °C (283.6 °F; 412.9 K)
2.6 g/100 mL, reacts (see text)
Vapor pressure 4 mmHg (20 °C)[1]
−52.8·10−6 cm3/mol
1.3901
Thermochemistry[2]
−624.4 kJ/mol
Pharmacology
Legal status
Hazards
GHS labelling:
GHS02: FlammableGHS05: CorrosiveGHS07: Exclamation mark
Danger
H226, H302, H314, H330
P210, P233, P240, P241, P242, P243, P260, P261, P264, P270, P271, P280, P301+P312, P301+P330+P331, P303+P361+P353, P304+P312, P304+P340, P305+P351+P338, P310, P312, P321, P330, P363, P370+P378, P403+P235, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g. diesel fuelInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazard W: Reacts with water in an unusual or dangerous manner. E.g. sodium, sulfuric acid
3
2
1
W
Flash point 49 °C (120 °F; 322 K)
316 °C (601 °F; 589 K)
Explosive limits 2.7–10.3%
Lethal dose or concentration (LD, LC):
1000 ppm (rat, 4 h)[3]
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 5 ppm (20 mg/m3)[1]
REL (Recommended)
 C 5 ppm (20 mg/m3)[1]
IDLH (Immediate danger)
 200 ppm[1]
Safety data sheet (SDS) ICSC 0209
Related compounds
Propionic anhydride
Related compounds
 Acetic acid
Acetyl chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Acetic anhydride, or ethanoic anhydride, is the chemical compound with the formula (CH3CO)2O. Commonly abbreviated Ac2O, it is the simplest isolable anhydride of a carboxylic acid and is widely used as a reagent in organic synthesis. It is a colorless liquid that smells strongly of acetic acid, which is formed by its reaction with moisture in the air.

  1. ^ a b c d NIOSH Pocket Guide to Chemical Hazards. "#0003". National Institute for Occupational Safety and Health (NIOSH).
  2. ^ John Rumble (June 18, 2018). CRC Handbook of Chemistry and Physics (99th ed.). CRC Press. pp. 5–3. ISBN 978-1138561632.
  3. ^ "Acetic anhydride". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).