Acetic acid

Acetic acid
Names
Preferred IUPAC name
Acetic acid[3]
Systematic IUPAC name
Ethanoic acid
Other names
Vinegar (when dilute); Hydrogen acetate; Methanecarboxylic acid; Ethylic acid[1][2]
Identifiers
CAS Number
3D model (JSmol)
Abbreviations AcOH
Beilstein Reference
506007
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.000.528
EC Number
  • 200-580-7
E number E260 (preservatives)
Gmelin Reference
1380
KEGG
MeSH Acetic+acid
PubChem CID
RTECS number
  • AF1225000
UNII
UN number 2789
InChI
  • InChI=1S/C2H4O2/c1-2(3)4/h1H3,(H,3,4) Y
    Key: QTBSBXVTEAMEQO-UHFFFAOYSA-N Y
SMILES
  • CC(O)=O
Properties
Chemical formula
CH3COOH
Molar mass 60.052 g·mol−1
Appearance Colourless liquid
Odor Heavily vinegar-like
Density 1.049 g/cm3 (liquid); 1.27 g/cm3 (solid)
Melting point 16 to 17 °C; 61 to 62 °F; 289 to 290 K
Boiling point 118 to 119 °C; 244 to 246 °F; 391 to 392 K
Solubility in water
Miscible
log P −0.28[4]
Vapor pressure 1.54653947 kPa (20 °C)
11.6 mmHg (20 °C)[5]
Acidity (pKa) 4.756
Conjugate base Acetate
Magnetic susceptibility (χ)
−31.54·10−6 cm3/mol
Refractive index (nD)
1.371 (VD = 18.19)
Viscosity 1.22 mPa s
1.22 cP
Dipole moment
1.74 D
Thermochemistry
Heat capacity (C)
123.1 J/(K⋅mol)
Std molar
entropy (S298)
158.0 J/(K⋅mol)
Std enthalpy of
formation fH298)
−483.88–483.16 kJ/mol
Std enthalpy of
combustion cH298)
−875.50–874.82 kJ/mol
Pharmacology
G01AD02 (WHO) S02AA10 (WHO)
Legal status
  • AU: S2 (Pharmacy medicine) and S6
Hazards
GHS labelling:
Pictograms
Signal word
Danger
Hazard statements
H226, H314
Precautionary statements
P280, P305+P351+P338, P310
NFPA 704 (fire diamond)
3
2
0
Flash point 40 °C (104 °F; 313 K)
Autoignition
temperature
427 °C (801 °F; 700 K)
Explosive limits 4–16%
Lethal dose or concentration (LD, LC):
3.31 g/kg, oral (rat)
5620 ppm (mouse, 1 h)
16000 ppm (rat, 4 h)[7]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 10 ppm (25 mg/m3)[6]
REL (Recommended)
TWA 10 ppm (25 mg/m3) ST 15 ppm (37 mg/m3)[6]
IDLH (Immediate danger)
50 ppm[6]
Related compounds
Related carboxylic acids
Formic acid
Propionic acid
Related compounds
Acetaldehyde
Acetamide
Acetic anhydride
Chloroacetic acid
Acetyl chloride
Glycolic acid
Ethyl acetate
Potassium acetate
Sodium acetate
Thioacetic acid
Supplementary data page
Acetic acid (data page)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references
Acetic acid
Clinical data
AHFS/Drugs.comMonograph
Identifiers
E numberE260 (preservatives)
CompTox Dashboard (EPA)
ECHA InfoCard100.000.528
Data page
Acetic acid (data page)

Acetic acid /əˈstɪk/, systematically named ethanoic acid /ˌɛθəˈnɪk/, is an acidic, colourless liquid and organic compound with the chemical formula CH3COOH (also written as CH3CO2H, C2H4O2, or HC2H3O2). Vinegar is at least 4% acetic acid by volume, making acetic acid the main component of vinegar apart from water. Historically, vinegar was produced from the third century BC and was likely the first acid to be produced in large quantities.

Acetic acid is the second simplest carboxylic acid (after formic acid). It is an important chemical reagent and industrial chemical across various fields, used primarily in the production of cellulose acetate for photographic film, polyvinyl acetate for wood glue, and synthetic fibres and fabrics. In households, diluted acetic acid is often used in descaling agents. In the food industry, acetic acid is controlled by the food additive code E260 as an acidity regulator and as a condiment. In biochemistry, the acetyl group, derived from acetic acid, is fundamental to all forms of life. When bound to coenzyme A, it is central to the metabolism of carbohydrates and fats.

The global demand for acetic acid as of 2023 is about 17.88 million metric tonnes per year (t/a). Most of the world's acetic acid is produced via the carbonylation of methanol. Its production and subsequent industrial use poses health hazards to workers, including incidental skin damage and chronic respiratory injuries from inhalation.

  1. ^ Scientific literature reviews on generally recognised as safe (GRAS) food ingredients. National Technical Information Service. 1974. p. 1.
  2. ^ "Chemistry", volume 5, Encyclopædia Britannica, 1961, page 374.
  3. ^ Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 745. doi:10.1039/9781849733069-00648. ISBN 978-0-85404-182-4.
  4. ^ "acetic acid". www.chemsrc.com.
  5. ^ Lange's Handbook of Chemistry, 10th ed.
  6. ^ a b c NIOSH Pocket Guide to Chemical Hazards. "#0002". National Institute for Occupational Safety and Health (NIOSH).
  7. ^ "Acetic acid". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).