Title: Acetoin
CAS Registry Number: 513-86-0
CAS Name: 3-Hydroxy-2-butanone
Additional Names: 2,3-butanolone; acetyl methyl carbinol; dimethylketol; g-hydroxy-b-oxobutane
Molecular Formula: C4H8O2
Molecular Weight: 88.11
Percent Composition: C 54.53%, H 9.15%, O 36.32%
Line Formula: CH3CH(OH)COCH3
Literature References: A product of fermentation, also in cream ripened for churning. Obtained by the action of sorbose bacterium or Mycoderma aceti on 2,3-butanediol or by the action of fungi, such as Aspergillus, Penicillium, Mycoderma on sugar cane juice: Browne, J. Am. Chem. Soc. 28, 467 (1906). By action of yeast on diacetyl: Nagelschmidt, Biochem. Z. 186, 317 (1927). From diacetyl by partial reduction with Zn and acid: Diels, Stephan, Ber. 40, 4338 (1907). Fermentation process: Vergnaud, US 2529061 (1950 to Usines de Melle).
Properties: Liquid. Pleasant odor. mp 15°. d417 0.9972. bp760 148°. nD17.3 1.4190. Miscible with water, alcohol. Sparingly sol in ether, petr ether. Reduces Fehling's soln forming acetic acid. Forms a solid dimer C8H16O4 on standing or on treatment with granulated zinc. The dimer is easily converted back to the monomer by melting, distilling or dissolving.
Melting point: mp 15°
Boiling point: bp760 148°
Index of refraction: nD17.3 1.4190
Density: d417 0.9972
Acetomeroctol Acetone Acetone Cyanohydrin Acetone Sodium Bisulfite Acetonedicarboxylic Acid

CAS number 513-86-0 YesY
PubChem 179
ChemSpider 21105851 YesY
EC number 208-174-1
KEGG C01769 YesY
ChEBI CHEBI:15688 YesY
RTECS number EL8790000
Jmol-3D images Image 1
Molecular formula C4H8O2
Molar mass 88.11 g mol−1
Appearance slightly yellow liquid or crystals
Odor bland, yogurt-like
Density 1.012 g/cm³
Melting point 15 °C; 59 °F; 288 K
Boiling point 148 °C; 298 °F; 421 K
Solubility in water soluble
Solubility soluble in alcohol
slightly soluble in ether, petroleum ether
miscible in propylene glycol
insoluble in vegetable oil
log P -0.36
Acidity (pKa) 13.72
Chiral rotation [α]D -39.4
Refractive index (nD) 1.4171
Flash point 41 °C; 106 °F; 314 K
LD50 > 5000 mg/kg (rat, oral)
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Acetoin, also known as 3-hydroxybutanone or acetyl methyl carbinol, with the molecular formula is C4H8O2, is a colorless or pale yellow to green yellow liquid with a pleasant, buttery odor. Acetoin is a chiral molecule. The form produced by bacteria is (R)-acetoin.[1]