3-Penten-2-one,4-methyl-

Reported in EPA TSCA Inventory.

OSHA PEL: TWA 15 ppm; STEL 25 ppm
ACGIH TLV: TWA 15 ppm; STEL 25 ppm
DFG MAK: 25 ppm (100 mg/m³)
NIOSH REL: (Ketones) TWA 40 mg/m³
DOT Classification:  3; Label: Flammable Liquid

For occupational chemical analysis use NIOSH: Ketones II (Desorption in 99:1 CS₂:methanol), 1301.

The Mesityl oxide, with the CAS registry number 141-79-7 and EINECS registry number 205-502-5, has the systhematic name of 4-methylpent-3-en-2-one. It is a is a α,β-Unsaturated ketone with the molecular formula of C₆H₁₀O. It is a kind of clear light yellow liquid, and belongs to the product category of Acetone series. What's more, it is usually used as mid-boiling point strong solvent.

The physical properties of Mesityl oxide are as followings: (1)ACD/LogP: 1.12; (2)# of Rule of 5 Violations: 0; (3)ACD/LogD (pH 5.5): 1.11; (4)ACD/LogD (pH 7.4): 1.11; (5)ACD/BCF (pH 5.5): 4.14; (6)ACD/BCF (pH 7.4): 4.14; (7)ACD/KOC (pH 5.5): 96.26; (8)ACD/KOC (pH 7.4): 96.26; (9)#H bond acceptors: 1; (10)#H bond donors: 0; (11)#Freely Rotating Bonds: 1; (12)Polar Surface Area: 17.07 Å²; (13)Index of Refraction: 1.418; (14)Molar Refractivity: 29.77 cm³; (15)Molar Volume: 118.1 cm³; (16)Polarizability: 11.8×10^-24cm³; (17)Surface Tension: 23.2 dyne/cm; (18)Density: 0.83 g/cm³; (19)Flash Point: 30.6 °C; (20)Enthalpy of Vaporization: 37.02 kJ/mol; (21)Boiling Point: 132.7 °C at 760 mmHg; (22)Vapour Pressure: 8.76 mmHg at 25°C.

Synthesis: It can be prepared by the aldol condensation of acetone to give diacetone alcohol, which readily dehydrates to give this compound.

Uses of Mesityl oxide: It can be used as a solvent and in the production of methyl isobutyl ketone by hydrogenation:

You should be cautious while dealing with this chemical. It is a kind of flammble chemical which is also harmful by inhalation, in contact with skin and if swallowed. Therefore, you had better avoid contact with eyes.

You can still convert the following datas into molecular structure:
(1)SMILES: O=C(\C=C(/C)C)C
(2)InChI: InChI=1/C6H10O/c1-5(2)4-6(3)7/h4H,1-3H3
(3)InChIKey: SHOJXDKTYKFBRD-UHFFFAOYAQ

The toxicity data is as follows:

Organism	Test Type	Route	Reported Dose (Normalized Dose)	Effect	Source
frog	LDLo	subcutaneous	1400mg/kg (1400mg/kg)		Archiv fuer Experimentelle Pathologie und Pharmakologie. Vol. 56, Pg. 346, 1906.
guinea pig	LCLo	inhalation	500ppm/8H (500ppm)	LUNGS, THORAX, OR RESPIRATION: OTHER CHANGES	Journal of Industrial Hygiene and Toxicology. Vol. 24, Pg. 46, 1942.
human	TCLo	inhalation	25ppm (25ppm)	SENSE ORGANS AND SPECIAL SENSES: CONJUNCTIVE IRRITATION: EYE	Journal of Industrial Hygiene and Toxicology. Vol. 28, Pg. 262, 1946.
mammal (species unspecified)	LD50	oral	710mg/kg (710mg/kg)		Gigiena i Sanitariya. For English translation, see HYSAAV. Vol. 39(4), Pg. 86, 1974.
mouse	LC50	inhalation	10gm/m3/2H (10000mg/m3)		"Toxicometric Parameters of Industrial Toxic Chemicals Under Single Exposure," Izmerov, N.F., et al., Moscow, Centre of International Projects, GKNT, 1982Vol. -, Pg. 80, 1982.
mouse	LD50	intraperitoneal	354mg/kg (354mg/kg)		Shell Chemical Company. Unpublished Report. Vol. -, Pg. 6, 1961.
mouse	LD50	oral	710mg/kg (710mg/kg)		"Toxicometric Parameters of Industrial Toxic Chemicals Under Single Exposure," Izmerov, N.F., et al., Moscow, Centre of International Projects, GKNT, 1982Vol. -, Pg. 80, 1982.
rabbit	LD50	oral	1gm/kg (1000mg/kg)		"Documentation of the Threshold Limit Values and Biological Exposure Indices," 5th ed., Cincinnati, OH, American Conference of Governmental Industrial Hygienists, Inc., 1986Vol. 6, Pg. 896, 1991.
rabbit	LD50	skin	5150mg/kg (5150mg/kg)		Raw Material Data Handbook, Vol.1: Organic Solvents, 1974. Vol. 1, Pg. 71, 1974.
rabbit	LDLo	subcutaneous	840mg/kg (840mg/kg)		Archiv fuer Experimentelle Pathologie und Pharmakologie. Vol. 56, Pg. 346, 1906.
rat	LC50	inhalation	9gm/m3/4H (9000mg/m3)		"Toxicometric Parameters of Industrial Toxic Chemicals Under Single Exposure," Izmerov, N.F., et al., Moscow, Centre of International Projects, GKNT, 1982Vol. -, Pg. 80, 1982.
rat	LD50	oral	1120mg/kg (1120mg/kg)		"Documentation of the Threshold Limit Values and Biological Exposure Indices," 5th ed., Cincinnati, OH, American Conference of Governmental Industrial Hygienists, Inc., 1986Vol. 6, Pg. 896, 1991.