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
CAS Number	108-24-7 ;
3D model (JSmol)	Interactive image; Interactive image;
ChEBI	CHEBI:36610 ;
ChEMBL	ChEMBL1305819;
ChemSpider	7630 ;
ECHA InfoCard	100.003.241
EC Number	203-564-8;
PubChem CID	7918;
RTECS number	AK1925000;
UNII	2E48G1QI9Q ;
UN number	1715
CompTox Dashboard (EPA)	DTXSID0024395 ;
	InChI InChI=1S/C4H6O3/c1-3(5)7-4(2)6/h1-2H3 Key: WFDIJRYMOXRFFG-UHFFFAOYSA-N ; InChI=1/C4H6O3/c1-3(5)7-4(2)6/h1-2H3 Key: WFDIJRYMOXRFFG-UHFFFAOYAH;
	SMILES O=C(OC(=O)C)C; CC(=O)OC(=O)C;
Properties
Chemical formula	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)
Solubility in water	2.6 g/100 mL, reacts (see text)
Vapor pressure	4 mmHg (20 °C)
Magnetic susceptibility (χ)	−52.8·10−6 cm3/mol
Refractive index (nD)	1.3901
Thermochemistry
Std enthalpy of; formation (ΔfH⦵298)	−624.4 kJ/mol
Pharmacology
Legal status	AU: S6 (Poison); CA: Schedule VI;
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H226, H302, H314, H330
Precautionary statements	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)	3 2 1 W
Flash point	49 °C (120 °F; 322 K)
Autoignition; temperature	316 °C (601 °F; 589 K)
Explosive limits	2.7–10.3%
	Lethal dose or concentration (LD, LC):
LC50 (median concentration)	1000 ppm (rat, 4 h)
	NIOSH (US health exposure limits):
PEL (Permissible)	TWA 5 ppm (20 mg/m3)
REL (Recommended)	C 5 ppm (20 mg/m3)
IDLH (Immediate danger)	200 ppm
Safety data sheet (SDS)	ICSC 0209
Related compounds
Related acid anhydrides	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). verify (what is ?) Infobox references

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.

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

[NIOSH-1] NIOSH Pocket Guide to Chemical Hazards. "#0003". National Institute for Occupational Safety and Health (NIOSH).

[crc-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).

[1]

[2]

[3]

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
CAS Number	108-24-7^Y
3D model (JSmol)	Interactive image Interactive image
ChEBI	CHEBI:36610^Y
ChEMBL	ChEMBL1305819
ChemSpider	7630^Y
ECHA InfoCard	100.003.241
EC Number	203-564-8
PubChem CID	7918
RTECS number	AK1925000
UNII	2E48G1QI9Q^Y
UN number	1715
CompTox Dashboard (EPA)	DTXSID0024395
InChI InChI=1S/C4H6O3/c1-3(5)7-4(2)6/h1-2H3^Y Key: WFDIJRYMOXRFFG-UHFFFAOYSA-N^Y InChI=1/C4H6O3/c1-3(5)7-4(2)6/h1-2H3 Key: WFDIJRYMOXRFFG-UHFFFAOYAH
SMILES O=C(OC(=O)C)C CC(=O)OC(=O)C
Properties
Chemical formula	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)
Solubility in water	2.6 g/100 mL, reacts (see text)
Vapor pressure	4 mmHg (20 °C)^[1]
Magnetic susceptibility (χ)	−52.8·10⁻⁶ cm³/mol
Refractive index (n_D)	1.3901
Thermochemistry^[2]
Std enthalpy of formation (Δ_fH^⦵₂₉₈)	−624.4 kJ/mol
Pharmacology
Legal status	AU: S6 (Poison) CA: Schedule VI
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H226, H302, H314, H330
Precautionary statements	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)	3 2 1 W
Flash point	49 °C (120 °F; 322 K)
Autoignition temperature	316 °C (601 °F; 589 K)
Explosive limits	2.7–10.3%
Lethal dose or concentration (LD, LC):
LC₅₀ (median concentration)	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
Related acid anhydrides	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). Y verify (what is ^YN ?) Infobox references