alpha-Methyl styrene

Synonyms & Trade Names

AMS [a-Methyl styrene], Isopropenyl benzene, 1-Methyl-1-phenylethylene, 2-Phenyl propylene

CAS No.

98-83-9

RTECS No.

WL5075300

DOT ID & Guide

Formula

C₆H₅C(CH₃)=CH₂

Conversion

1 ppm = 4.83 mg/m³

IDLH

700 ppm
See: 98839

Exposure Limits

NIOSH REL

TWA 50 ppm (240 mg/m³) ST 100 ppm (485 mg/m³)

OSHA PEL

C 100 ppm (480 mg/m³) See Appendix G

Measurement Methods

NIOSH 1501;
OSHA 7
See: NMAM or OSHA Methods

Physical Description

Colorless liquid with a characteristic odor.

Molecular Weight

118.2

Boiling Point

330°F

Freezing Point

-10°F

Solubility

Insoluble

Vapor Pressure

2 mmHg

Ionization Potential

8.35 eV

Specific Gravity

0.91

Flash Point

129°F

Upper Explosive Limit

6.1%

Lower Explosive Limit

1.9%

Class II Combustible Liquid: Fl.P. at or above 100°F and below 140°F.

Incompatibilities & Reactivities

Oxidizers, peroxides, halogens, catalysts for vinyl or ionic polymers; aluminum, iron chloride, copper [Note: Usually contains an inhibitor such as tert-butyl catechol.]

Exposure Routes

inhalation, ingestion, skin and/or eye contact

Symptoms

irritation eyes, skin, nose, throat; drowsiness; dermatitis

Target Organs

Eyes, skin, respiratory system, central nervous system

Personal Protection/Sanitation

(See protection codes)
Skin:Prevent skin contact
Eyes:Prevent eye contact
Wash skin:When contaminated
Remove:When wet or contaminated
Change:No recommendation

First Aid

(See procedures)
Eye:Irrigate immediately
Skin:Water flush promptly
Breathing:Respiratory support
Swallow:Medical attention immediately

Respirator Recommendations

NIOSH

Up to 500 ppm:
(APF = 10) Any chemical cartridge respirator with organic vapor cartridge(s)*
(APF = 10) Any supplied-air respirator*

Up to 700 ppm:
(APF = 25) Any supplied-air respirator operated in a continuous-flow mode*
(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 = 25) Any powered, air-purifying respirator with 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

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

alpha-Methyl styrene

NIOSH REL

OSHA PEL

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