Mesityl oxide

Mesityl oxide
Names
	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 ;
3D model (JSmol)	Interactive image;
ChemSpider	8526 ;
ECHA InfoCard	100.005.002
RTECS number	SB4200000;
CompTox Dashboard (EPA)	DTXSID1029170 ;
	InChI InChI=1S/C6H10O/c1-5(2)4-6(3)7/h4H,1-3H3 Key: SHOJXDKTYKFBRD-UHFFFAOYSA-N ; 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
Odor	peppermint- or honey-like
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)
Solubility in other solvents	Soluble in most organic solvents
Vapor pressure	9 mmHg (20°C)
Refractive index (nD)	1.442
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	flammable
Flash point	31 °C; 87 °F; 304 K
Explosive limits	1.4%-7.2%
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	1120 mg/kg (rat, oral); 1000 mg/kg (rabbit, oral); 710 mg/kg (mouse, oral)
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)
	NIOSH (US health exposure limits):
PEL (Permissible)	TWA 25 ppm (100 mg/m3)
REL (Recommended)	TWA 10 ppm (40 mg/m3)
IDLH (Immediate danger)	1400 ppm
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). verify (what is ?) 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]

Synthesis

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

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:

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

References

^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ NIOSH Pocket Guide to Chemical Hazards. "#0385". National Institute for Occupational Safety and Health (NIOSH).
^ ^a ^b "Mesityl oxide". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
^ Merck Index, 14th Edition
^ J. B. Conant and Neal Tuttle (1941). "Mesityl oxide". Organic Syntheses; Collected Volumes, vol. 1, p. 345.

External links

[PGCH-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).

[IDLH-2] "Mesityl oxide". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).

[3] Merck Index, 14th Edition

[4] J. B. Conant and Neal Tuttle (1941). "Mesityl oxide". Organic Syntheses; Collected Volumes, vol. 1, p. 345.

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