Mesityl oxide

Mesityl oxide is a α,β-unsaturated ketone with the formula CH₃C(O)CH=C(CH₃)₂. This compound is a colorless, volatile liquid with a honey-like odor.^[3]

Mesityl oxide

Mesityl oxide
Names
Preferred IUPAC name 4-Methylpent-3-en-2-one
Other names Mesityl oxide Isobutenyl methyl ketone Methyl isobutenyl ketone Isopropylidene acetone
Identifiers
CAS Number	141-79-7 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:89993
ChEMBL	ChEMBL3185916
ChemSpider	8526 Y
ECHA InfoCard	100.005.002
EC Number	205-502-5
PubChem CID	8858
RTECS number	SB4200000
UNII	77LAC84669
UN number	1229
CompTox Dashboard (EPA)	DTXSID1029170
InChI InChI=1S/C6H10O/c1-5(2)4-6(3)7/h4H,1-3H3 Y Key: SHOJXDKTYKFBRD-UHFFFAOYSA-N Y InChI=1/C6H10O/c1-5(2)4-6(3)7/h4H,1-3H3
SMILES O=C(\C=C(/C)C)C
Properties
Chemical formula	C6H10O
Molar mass	98.145 g·mol−1
Appearance	Oily, colorless to light-yellow liquid[1]
Odor	peppermint- or honey-like[1]
Density	0.858 g/cm3
Melting point	−53 °C (−63 °F; 220 K)
Boiling point	129.5 °C (265.1 °F; 402.6 K)
Solubility in water	3% (20°C)[1]
Solubility in other solvents	Soluble in most organic solvents
Vapor pressure	9 mmHg (20°C)[1]
Refractive index (nD)	1.442
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	flammable
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H226, H302, H312, H332
Precautionary statements	P210, P233, P240, P241, P242, P243, P261, P264, P270, P271, P280, P301+P312, P302+P352, P303+P361+P353, P304+P312, P304+P340, P312, P322, P330, P363, P370+P378, P403+P235, P501
Flash point	31 °C; 87 °F; 304 K[1]
Explosive limits	1.4–7.2%[1]
Lethal dose or concentration (LD, LC):
LD50 (median dose)	1120 mg/kg (rat, oral) 1000 mg/kg (rabbit, oral) 710 mg/kg (mouse, oral)[2]
LC50 (median concentration)	1000 mg/m3 (rat, 4 hr) 9000 mg/m3 (rat, 4 hr) 10,000 mg/m3 (mouse, 2 hr) 2000 mg/m3 (guinea pig, 7 hr)[2]
NIOSH (US health exposure limits):
PEL (Permissible)	TWA 25 ppm (100 mg/m3)[1]
REL (Recommended)	TWA 10 ppm (40 mg/m3)[1]
IDLH (Immediate danger)	1400 ppm[1]
Related compounds
Related compounds	diacetone alcohol acetone, benzylideneacetone
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Synthesis

It is prepared by the aldol condensation of acetone to give diacetone alcohol, which readily dehydrates to give this compound.^[4][5]

Phorone and isophorone may be formed under the same conditions. Isophorone originates via a Michael addition:

Phorone is formed by continued aldol condensation:

Uses

Mesityl oxide is used as a solvent and in the production of methyl isobutyl ketone by hydrogenation:^[5]

Further hydrogenation gives 4-methyl-2-pentanol (methyl isobutyl carbinol).

Dimedone is another established use of mesityl oxide.