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)
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).
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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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