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
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.005.002 Edit this at Wikidata
EC Number
  • 205-502-5
RTECS number
  • SB4200000
UNII
UN number 1229
  • InChI=1S/C6H10O/c1-5(2)4-6(3)7/h4H,1-3H3 checkY
    Key: SHOJXDKTYKFBRD-UHFFFAOYSA-N checkY
  • InChI=1/C6H10O/c1-5(2)4-6(3)7/h4H,1-3H3
  • O=C(\C=C(/C)C)C
Properties
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)
3% (20°C)[1]
Solubility in other solvents Soluble in most organic solvents
Vapor pressure 9 mmHg (20°C)[1]
1.442
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
flammable
GHS labelling:
GHS02: FlammableGHS07: Exclamation mark
Warning
H226, H302, H312, H332
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):
1120 mg/kg (rat, oral)
1000 mg/kg (rabbit, oral)
710 mg/kg (mouse, oral)[2]
1000 mg/m3 (rat, 4 hr)
9500 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).
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Synthesis

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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

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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.

References

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  1. ^ a b c d e f g h i NIOSH Pocket Guide to Chemical Hazards. "#0385". National Institute for Occupational Safety and Health (NIOSH).
  2. ^ a b "Mesityl oxide". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  3. ^ Merck Index, 14th Edition
  4. ^ Conant, J. B.; Tuttle, N. (1921). "Mesityl Oxide". Organic Syntheses. 1: 53. doi:10.15227/orgsyn.001.0053.
  5. ^ a b Sifniades, Stylianos; Levy, Alan B. (2000). "Acetone". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a01_079. ISBN 3527306730.
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