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Names | |||
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Preferred IUPAC name
(Prop-1-en-2-yl)benzene | |||
Other names
2-Phenylpropene; 2-Phenylpropylene; 1-Methyl-1-phenylethylene; 1-Methyl-1-phenylethene; 1-Phenyl-1-methylethylene; 1-Phenyl-1-methylethene; (1-Methylethenyl)benzene; β-Phenylpropene; β-Phenylpropylene; α-Methylstyrol; α-Methylvinylbenzene; Isopropenylbenzene
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Identifiers | |||
3D model (
JSmol)
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Abbreviations | AMS | ||
ChEBI | |||
ChEMBL | |||
ChemSpider | |||
ECHA InfoCard | 100.002.459 | ||
EC Number |
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KEGG | |||
PubChem
CID
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RTECS number |
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UNII | |||
UN number | 2303 | ||
CompTox Dashboard (
EPA)
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Properties | |||
C9H10 | |||
Molar mass | 118.179 g·mol−1 | ||
Appearance | Colorless liquid | ||
Density | 0.91 g/cm3 | ||
Melting point | −24 °C (−11 °F; 249 K) | ||
Boiling point | 165 to 169 °C (329 to 336 °F; 438 to 442 K) | ||
Insoluble | |||
Vapor pressure | 2 mmHg (20 °C) [1] | ||
-80.1·10−6 cm3/mol | |||
Hazards | |||
GHS labelling: [3] | |||
Warning | |||
H226, H319, H335, H411 | |||
P210, P233, P240, P241, P242, P243, P261, P264+P265, P271, P273, P280, P303+P361+P353, P304+P340, P305+P351+P338, P319, P337+P317, P370+P378, P391, P403+P233, P403+P235, P405, P501 | |||
NFPA 704 (fire diamond) | |||
Flash point | 45 °C (113 °F; 318 K) | ||
Explosive limits | 1.9–6.1% [1] | ||
Lethal dose or concentration (LD, LC): | |||
LD50 (
median dose)
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4900 mg/kg (oral, rat) [2] | ||
NIOSH (US health exposure limits): | |||
PEL (Permissible)
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C 100 ppm (480 mg/m3) [1] | ||
REL (Recommended)
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TWA 50 ppm (240 mg/m3) ST 100 ppm (485 mg/m3) [1] | ||
IDLH (Immediate danger)
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700 ppm [1] | ||
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
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α-Methylstyrene (AMS) is an organic compound with the formula C6H5C(CH3)=CH2. It is a colorless oil. [4]
AMS is formed as a by-product of the Cumene process. In this procedure, cumene is converted to its radical, through a reaction with oxygen.
Normally these cumene radicals are converted to cumene hydroperoxide, however they can also undergo radical disproportionation to form AMS.
Although this is only a minor side reaction, the cumene process is run at such a large scale that the recovery of AMS is commercially viable and satisfies much of the global demand. AMS can also be produced by dehydrogenation of cumene.
The homopolymer obtained from this monomer, poly(α-methylstyrene), is unstable, being characterized by a low ceiling temperature of 65 C. [5] [6]
The American Conference of Governmental Industrial Hygienists (2009) defined occupational exposure limits of 10 ppm for airborne concentrations of a-methylstyrene. [7] based on allergic reactions, and effects on the central nervous system. [7] [8]