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IUPAC name 4-Phenyl-3-buten-2-one
Other names Benzalacetone
Methyl styryl ketone
Benzylidene acetone
CAS number 122-57-6
RTECS number EN0330000
Molecular formula C10H10O
Molar mass 146.19 g/mol
Appearance pale yellow solid
Density 1.008 g/cm3
Melting point

39-42 °C

Boiling point

260-262 °C

Solubility in water 1.3 g/L
Solubility in other solvents nonpolar solvents
Main hazards irritant
R-phrases 36/37/38-43
S-phrases 22-26-36/37
Flash point 116 °C
Related Compounds
Related compounds Dibenzylideneacetone
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Benzylideneacetone is the organic compound described by the formula C6H5CH=CHC(O)CH3. Although both cis and trans isomers are possible for the α,β-unsaturated ketone, only the trans isomer is observed. Its original preparation demonstrated the scope of condensation reactions to construct new, complex organic compounds.[1]


Benzylideneacetone can be efficiently prepared by the NaOH-induced condensation of the readily available reagents acetone and benzaldehyde:[2]



The compound undergoes the reactions expected for its collection of functional groups: e.g., the double bond adds bromine, the heterodiene adds electron-rich alkenes in Diels-Alder reactions to give dihydropyrans, the methyl group undergoes further condensation with benzaldehyde to give dibenzylideneacetone, and the carbonyl forms hydrazones. Treatment of benzylideneacetone with the Grignard reagent methyl magnesium bromide followed by acid-induced dehydration gives 1-phenyl-1,3-butadiene.[3] It reacts with Fe2(CO)9 to give (benzylideneacetone)Fe(CO)3, a reagent for transferring the Fe(CO)3 unit to other organic molecules.[4]


  1. ^ Claisen, L. “Über die Einwirkung von Aceton auf Furfural und auf Benzaldehyd bei Gegenwart von Alkalilauge” Berichte der deutschen chemischen Gesellschaft 1881, volume 14, p 2468-2471.
  2. ^ Drake, N. L.; Allen, Jr. P.. "Benzalacetone". Org. Synth.; Coll. Vol. 1: 77. 
  3. ^ Grummitt, O.; Becker, E. I. (1963). "trans-1-Phenyl-1,3-butadiene". Org. Synth.; Coll. Vol. 4: 771. 
  4. ^ Knölker, H.-J. "(η4-Benzylideneacetone)tricarbonyliron" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Benzylideneacetone". A list of authors is available in Wikipedia.
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