Α-Methylstyrene
{{lowercase title}}
{{chembox
|Watchedfields = changed
|verifiedrevid = 477319488
|Name = α-Methylstyrene
|ImageFileL1 = Alpha-methylstyrol.svg
|ImageNameL1 = Skeletal formula
|ImageFileR1 = Alpha-methylstyrene-from-xtal-3D-bs-17.png
|ImageNameR1 = Ball-and-stick model
|PIN =(Prop-1-en-2-yl)benzene
|OtherNames =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
|Section1={{Chembox Identifiers
|Abbreviations = AMS
| ChEBI = 35060
| ChEMBL = 1344773
|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
|ChemSpiderID = 7129
| EC_number = 202-705-0
|KEGG_Ref = {{keggcite|correct|kegg}}
|KEGG = C14395
|InChI = 1/C9H10/c1-8(2)9-6-4-3-5-7-9/h3-7H,1H2,2H3
|InChIKey = XYLMUPLGERFSHI-UHFFFAOYAS
|SMILES1 = CC(=C)c1ccccc1
|StdInChI_Ref = {{stdinchicite|correct|chemspider}}
|StdInChI = 1S/C9H10/c1-8(2)9-6-4-3-5-7-9/h3-7H,1H2,2H3
|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
|StdInChIKey = XYLMUPLGERFSHI-UHFFFAOYSA-N
|CASNo_Ref = {{cascite|correct|CAS}}
|CASNo=98-83-9
| RTECS = WL5075300
| UNNumber = 2303
|UNII_Ref = {{fdacite|correct|FDA}}
|UNII = D46R9753IK
|PubChem=7407
|SMILES = C=C(c1ccccc1)C
}}
|Section2={{Chembox Properties
|C = 9
|H = 10
|Appearance=Colorless liquid
|Density= 0.91 g/cm3
|MeltingPtC= -24
|BoilingPtC = 165 to 169
|Solubility=Insoluble
|VaporPressure = 2 mmHg (20 °C)
|MagSus = −80.1·10−6 cm3/mol
}}
|Section3={{Chembox Hazards
| GHSPictograms = {{GHS02}}{{GHS07}}{{GHS09}}
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|226|319|335|411}}
| PPhrases = {{P-phrases|210|233|240|241|242|243|261|264+265|271|273|280|303+361+353|304+340|305+351+338|319|337+317|370+378|391|403+233|403+235|405|501}}
|MainHazards=
|NFPA-H = 3
|NFPA-F = 0
|NFPA-R = 0
|FlashPtC = 45
|PEL = C 100 ppm (480 mg/m3){{PGCH|0429}}
|REL = TWA 50 ppm (240 mg/m3) ST 100 ppm (485 mg/m3)
|LD50 = 4900 mg/kg (oral, rat){{IDLH|98839|alpha-Methyl styrene}}
}}
}}
α-Methylstyrene (AMS) is an organic compound with the formula C6H5C(CH3)=CH2. It is a colorless oil.{{Ullmann |first1=Denis H. |last1=James |first2=William M. |last2=Castor |title=Styrene |year=2007 |doi=10.1002/14356007.a25_329.pub2}}
Synthesis and reactions
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.{{cite book|last=Stevens|first=Malcolm P.|title=Polymer Chemistry an Introduction|year=1999|publisher=Oxford University Press|location=New York|isbn=978-0-19-512444-6|pages=193–194|edition=3rd|chapter=6}}{{cite journal | pmc=10176471 | date=2023 | last1=Jones | first1=G. R. | last2=Wang | first2=H. S. | last3=Parkatzidis | first3=K. | last4=Whitfield | first4=R. | last5=Truong | first5=N. P. | last6=Anastasaki | first6=A. | title=Reversed Controlled Polymerization (RCP): Depolymerization from Well-Defined Polymers to Monomers | journal=Journal of the American Chemical Society | volume=145 | issue=18 | pages=9898–9915 | doi=10.1021/jacs.3c00589 | pmid=37127289 }}
Side effects in humans
The American Conference of Governmental Industrial Hygienists (2009) defined occupational exposure limits of 10 ppm for airborne concentrations of α-methylstyrene{{Cite journal |last1=Morgan |first1=D. L. |last2=Mahler |first2=J. F. |last3=Kirkpatrick |first3=D. T. |last4=Price |first4=H. C. |last5=O'Connor |first5=R. W. |last6=Wilson |first6=R. E. |last7=Moorman |first7=M. P. |date=February 1999 |title=Characterization of inhaled alpha-methylstyrene vapor toxicity for B6C3F1 mice and F344 rats |journal=Toxicological Sciences|volume=47 |issue=2 |pages=187–194 |doi=10.1093/toxsci/47.2.187 |issn=1096-6080 |pmid=10220856|doi-access=free}} based on allergic reactions and effects on the central nervous system.{{Cite web |work=OSHA |title=α-METHYL STYRENE† |url=https://www.osha.gov/chemicaldata/776}}