Acetoacetic acid

Acetoacetic acid
Acetoacetic acid
CAS number 541-50-4 YesY
PubChem 96
ChemSpider 94 YesY
DrugBank DB04025
KEGG C00164 YesY
ChEBI CHEBI:15344 YesY
Jmol-3D images Image 1
Molecular formula C4H6O3
Molar mass 102.09 g/mol
Melting point

36.5 °C

Boiling point


Acidity (pKa) 3.58 [1]
 N acid (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Acetoacetic acid (also called diacetic acid) is the organic compound with the formula CH3C(O)CH2CO2H. It is the simplest beta-keto acid group and like other members of this class is unstable.


Synthesis and properties

Acetoacetic acid is a weak acid (like most alkyl carboxylic acids) with a pKa of 3.77. It can be prepared by the hydrolysis of the ethyl acetoacetate followed by acidification of the anion.[2] In general, acetoacetic acid is generated at 0 °C and used in situ immediately.[3] It decomposes at a moderate rate to acetone and carbon dioxide:


The acid form has a half-life of 140 minutes at 37°C in water, whereas the basic form (the anion) has a half-life of 130 hours. That is, it reacts about 50 times more slowly.[4]


When ketone bodies are measured by way of urine concentration, acetoacetic acid, along with beta-hydroxybutyric acid (BHB), and acetone, is what is detected. This is done using dipsticks coated in nitroprusside or similar reagents. Nitroprusside changes from pink to purple in the presence of acetoacetate, the conjugate base of acetoacetic acid, and the colour change is graded by eye. The popular dipstick used to detect ketone bodies in urine "Ketostix" by Bayer, only detects acetoacetate, not BHB or acetone.

See also


  1. ^ Dawson, R. M. C., et al., Data for Biochemical Research, Oxford, Clarendon Press, 1959.
  2. ^ Robert C. Krueger (1952). "Crystalline Acetoacetic Acid". Journal of the American Chemical Society 74 (21): 5536–5536. doi:10.1021/ja01141a521. 
  3. ^ George A. Reynolds and J. A. VanAllan "Methylglyoxal-ω-Phenylhydrazone" Organic Syntheses, Collected Volume 4, p.633 (1963).
  4. ^ Hay, R. W.; Bond, M. A. (1967). "Kinetics of decarboxilation of acetoacetic acid". Aust. J. Chem. 20 (9): 1823–8. doi:10.1071/CH9671823. 

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Look at other dictionaries:

  • acetoacetic acid — One of the ketone bodies, formed in excess and appearing in the urine in starvation or diabetes. * * * ace·to·ace·tic acid .as ə (.)tō ə .sēt ik , ə .sēt ō n an unstable acid C4H6O3 that is one of the ketone bodies found in abnormal amounts in… …   Medical dictionary

  • acetoacetic acid — an organic acid produced in large amounts by the liver under metabolic conditions associated with a high rate of fatty acid oxidation (for example, in starvation). The acetoacetic acid thus formed is subsequently converted to acetone and excreted …   The new mediacal dictionary

  • acetoacetic acid — acetoacto rūgštis statusas T sritis chemija formulė CH₃COCH₂COOH atitikmenys: angl. acetoacetic acid rus. ацетоуксусная кислота ryšiai: sinonimas – 3 oksobutano rūgštis …   Chemijos terminų aiškinamasis žodynas

  • acetoacetic acid — noun Etymology: part translation of German Azetessigsäure, from azet acet + Essigsäure acetic acid Date: circa 1900 an unstable acid C4H6O3 that is a ketone body found in abnormal quantities in the blood and urine in some conditions (as diabetes) …   New Collegiate Dictionary

  • acetoacetic acid — noun unstable acid found in abnormal amounts in the blood and urine in some cases of impaired metabolism (as diabetes mellitus or starvation) • Hypernyms: ↑ketone body, ↑acetone body * * * /euh see toh euh see tik, euh set ik, as i toh /, Chem. a …   Useful english dictionary

  • acetoacetic acid — /euh see toh euh see tik, euh set ik, as i toh /, Chem. a colorless, oily liquid, C4H6O3, soluble in water, alcohol, and ether: used in synthetic organic chemistry. Also called diacetic acid. [1895 1900; ACETO + ACETIC] * * * …   Universalium

  • acetoacetic acid — noun The ketonic carboxylic acid CH CO CH COOH, that is present in the urine of people suffering from starvation or some forms of diabetes See Also: acetoacetate …   Wiktionary

  • acetoacetic acid — /əˌsitoʊəsitɪk ˈæsəd/ (say uh.seetohuhseetik asuhd), / əsɛtɪk/ (say uhsetik) noun a carboxylic acid, CH3COCH2COOH; excreted in urine and found in abnormal quantities in the urine of diabetics; one of the ketone bodies …  

  • acetoacetic acid — a•ce•to•a•ce′tic ac′id [[t]əˌsi toʊ əˈsi tɪk, əˈsɛt ɪk, ˌæs ɪ toʊ [/t]] n. chem. a colorless, oily liquid, C4H6O3, soluble in water, alcohol, and ether: used in synthetic organic chemistry • Etymology: 1895–1900 …   From formal English to slang

  • Кислота Ацетоуксусная (Acetoacetic Acid) — органическая кислота, вырабатываемая в больших количествах печенью в процессе метаболизма и вступающая с большой скоростью в окислительные реакции с жирными кислотами (например, при голодании). Образовавшаяся ацетоуксусная кислота при достаточно… …   Медицинские термины

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