Mesityl oxide

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
Mesityl oxide
Mesityl oxide
IUPAC name
Other names
Mesityl oxide
Isobutenyl methyl ketone
Methyl isobutenyl ketone
Isopropylidene acetone
3D model (JSmol)
ECHA InfoCard 100.005.002
RTECS number SB4200000
Molar mass 98.15 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]
Main hazards flammable
R-phrases (outdated) R10 R20/21/22
S-phrases (outdated) S25
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]
US health exposure limits (NIOSH):
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
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☑Y verify (what is ☑Y☒N ?)
Infobox references

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]


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

Acetone mesityl oxide.png

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

Isophorone mesityl oxide.png

Phorone is formed by continued aldol condensation:

Phoron formation.svg


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

Hydrogenation of mesityl oxide to MIBK.png

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


  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 and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  3. ^ Merck Index, 14th Edition
  4. ^ J. B. Conant and Neal Tuttle (1921). "Mesityl Oxide". 1: 53. doi:10.15227/orgsyn.001.0053.

External links[edit]