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Mesityl oxide

Synonyms & Trade Names
Isobutenyl methyl ketone, Isopropylideneacetone, Methyl isobutenyl ketone, 4-Methyl-3-penten-2-one
CAS No.
141-79-7
RTECS No.
SB4200000
DOT ID & Guide
1229 129
Formula
(CH₃)₂C=CHCOCH₃
Conversion
1 ppm = 4.02 mg/m3
IDLH
1400 ppm [10%LEL]
See: 141797
Exposure Limits
NIOSH REL
TWA 10 ppm (40 mg/m3)
OSHA PEL
TWA 25 ppm (100 mg/m3) See Appendix G
Measurement Methods
NIOSH 1301 , 2553;
OSHA 7
See: NMAM or OSHA Methods
Physical Description
Oily, colorless to light-yellow liquid with a peppermint- or honey-like odor.
Molecular Weight
98.2
Boiling Point
266°F
Freezing Point
-52°F
Solubility
3%
Vapor Pressure
9 mmHg
Ionization Potential
9.08 eV
Specific Gravity
(59°F): 0.86
Flash Point
87°F
Upper Exposive Limit
7.2%
Lower Explosive Limit
1.4%
Class IC Flammable Liquid: Fl.P. at or above 73°F and below 100°F.
Incompatibilities & Reactivities
Oxidizers, acids
Exposure Routes
inhalation, ingestion, skin and/or eye contact
Symptoms
irritation eyes, skin, mucous membrane; narcosis, coma; In Animals: liver, kidney damage; central nervous system effects
Target Organs
Eyes, skin, respiratory system, central nervous system, liver, kidneys
Personal Protection/Sanitation
(See protection codes)
Skin:Prevent skin contact
Eyes:Prevent eye contact
Wash skin:When contaminated
Remove:When wet (flammable)
Change:No recommendation
Provide:Quick drench
First Aid
(See procedures)
Eye:Irrigate immediately
Skin:Water flush immediately
Breathing:Respiratory support
Swallow:Medical attention immediately
Respirator Recommendations

NIOSH

Up to 250 ppm:
(APF = 25) Any supplied-air respirator operated in a continuous-flow mode£
(APF = 25) Any powered, air-purifying respirator with organic vapor cartridge(s)£

Up to 500 ppm:
(APF = 50) Any chemical cartridge respirator with a full facepiece and organic vapor cartridge(s)
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister
(APF = 50) Any powered, air-purifying respirator with a tight-fitting facepiece and organic vapor cartridge(s)£
(APF = 50) Any self-contained breathing apparatus with a full facepiece
(APF = 50) Any supplied-air respirator with a full facepiece

Up to 1400 ppm:
(APF = 2000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode

Emergency or planned entry into unknown concentrations or IDLH conditions:
(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus

Escape:
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister
Any appropriate escape-type, self-contained breathing apparatus

Important additional information about respirator selection

See also
INTRODUCTION   ICSC CARD: 0814

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