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| Stilbene | |
|---|---|
| General | |
| Systematic name | trans-1,2-diphenylethylene | (E)-1,2-diphenylethene
| Other Names | (E)-stilbene |
| trans-stilbene | |
| Molecular formula | C14H12 |
| C6H5CH=CHC6H5 | |
| SMILES | c1(/C=C/c2ccccc2)ccccc1 |
| Molar mass | 180.24928 g/mol |
| Appearance | Solid |
| Color | white - slightly beige |
| CAS number | 103-30-0 |
| Properties | |
| Solubility in water | practically insoluble |
| Melting point | 122°C - 125°C |
| Boiling point | 305°C - 307°C |
| Flash Point | >112°C |
| Hazards | |
| MSDS | External MSDS |
| NFPA 704 | nfpa_f1.pngnfpa_r0.png|
| Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) Chemical infobox | |
Officially known as trans-1,2-diphenylethylene, aka, stilbene, or more specifically, (E)-stilbene, is the alkene, ethene with two phenyl groups on either carbon of the parent chain. The name was derived from the Greek word stilbos, which means shining. It should also be noted, there is also a (Z)-stilbene which is sterically hindered and less stable because of it. Also notice that (Z)-stilbene has a melting point of 5°C to 6°C, while the melting point of (E)-stilbene is in the 125°C area, this illustrates the significant differences between the two. Because (E)-stilbene is so much more common than (Z)-stilbene, this page will focus only on (E)-stilbene.
Its risk and safety phrases are A .
Uses of Stilbene
Stilbene is used in manufacture of dyes and optical brighteners, and also as a phosphor and a scintillator.
Stilbene is one of the gain mediums used in dye lasers.
Many stilbene derivates (stilbenoids) are present naturally in plants. An example is resveratrol.
Stilbene Reactions
Halogenation of Stilbene
Simple hydrocarbons are relatively unreactive. In order to form more complex molecules, it is generally necessary to introduce more reactive functional groups. Alkenes (olefins) containing the carbon-carbon double bond may be halogenated to form alkyl halides, which are more capable of undergoing further chemical reactions.
An example of halogenation is the bromination of (E)-stilbene. Bromine is somewhat of a special case due in no small part, to its relatively enormous size compared to carbon. Since elemental bromine (Br2) is volatile and highly corrosive, pyridinium tribromide is commonly used to generate Br2 in situ.
Greener Halogenation of Stilbene
To green this reaction, the pyridinium tribromide in situ generation of Br2 is replaced with hydrobromic acid, which is oxidized by hydrogen peroxide(H2O2).
- 2HBr + H2O2 → Br2 + 2H2O
In either case the halogenation of stilbene is as follows; as seen in the first reaction, the Br-Br bond attracts the attention of the π-bonding electrons (π-bonds being e- dense and Br being very electronegative), this leads to a weakening and eventual break (heat, plays a crucial role in driving the break forward) of the π-bond. Once the π-bond has been broken, its electrons are transferred to Br2, causing the Br-Br bond to be severed when the bonding electrons are transferred to the other bromine. At this stage there is the positivly charged intermidiate and the loose bromine ion (Br-), coming from the opposite direction as the Br2, the Br- loosens one of the C-Br Bonds, leaving the final brominated product.
It doesn't matter which stilbene is used for this reaction, (E)-stilbene and (Z)-stilbene will both produce 1,2-dibromo-1,2-diphenylethane.
More Information
Spectra
See also
References
- Spectral Database for Organic Compounds, SDBS
- (E)-Stilbene on ChemExper
- Green Organic Chemisrty, Strategies, tools, and Laboratory Experiments. Kenneth M, Doxsee & James E. Hutchison.
- Organic Chemistry, Eighth Edition. T.W. Graham Solomonds & Craig B. Fryhle.
External links
Aromatic hydrocarbons | Luminescence | Fluorescent dyes | Phosphors and scintillators
"Stilbene"
