Acetoacetic acid

Acetoacetic acid

Names
Preferred IUPAC name 3-Oxobutanoic acid
Other names Acetoacetic acid (no longer recommended) Diacetic acid
Identifiers
CAS Number	541-50-4 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:15344 Y
ChEMBL	ChEMBL1230762 N
ChemSpider	94 Y
DrugBank	DB01762 N
KEGG	C00164 Y
PubChem	96
InChI InChI=1S/C4H6O3/c1-3(5)2-4(6)7/h2H2,1H3,(H,6,7) Y Key: WDJHALXBUFZDSR-UHFFFAOYSA-N Y InChI=1/C4H6O3/c1-3(5)2-4(6)7/h2H2,1H3,(H,6,7) Key: WDJHALXBUFZDSR-UHFFFAOYAH
SMILES O=C(C)CC(=O)O
Properties
Chemical formula	C4H6O3
Molar mass	102.088 g/mol
Appearance	colorless, oily liquid
Melting point	36.5 °C (97.7 °F; 309.6 K)
Boiling point	Decomposes
Solubility in water	soluble
Solubility	soluble in ethanol, ether
Acidity (pKa)	3.58
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Acetoacetic acid (also diacetic acid) is the organic compound with the formula CH₃COCH₂COOH. It is the simplest beta-keto acid group, and like other members of this class it is unstable. The methyl and ethyl esters, which are quite stable, are produced on a large scale industrially as precursors to dyes.

Acetoacetic acid is a weak acid. It is of biochemical importance in various animals, including humans, as one of the endogenous ketone bodies produced by the liver when it breaks down fatty acids into Acetyl-CoA and TCA cycle intermediates are depleted (particularly oxaloacetate, which is formed from pyruvate derived from glycolysis). It can be viewed as the product of joining two acetic acid molecules via a condensation reaction that ejects a water molecule in the process, although that is only one of the ways of forming the acetoacetate molecule. In the human body, a large portion of acetoacetate is converted to beta-hydroxybutyrate, a rich energy source for the brain, which cannot run directly on fatty acids themselves due to their poor ability to cross the blood-brain barrier.

In general, the esters are prepared from diketene by treatment with alcohols. Acetoacetic acid can be prepared by the hydrolysis of the ethyl acetoacetate followed by acidification of the anion. In general, acetoacetic acid is generated at 0 °C and used in situ immediately. It decomposes at a moderate rate to acetone and carbon dioxide: