| Benzophenone | |
|---|---|
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diphenylmethanone |
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Other names
phenyl ketone; diphenyl ketone; benzoylbenzene |
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| Identifiers | |
| CAS number | 119-61-9 |
| PubChem | 3102 |
| ChemSpider | 2991 |
| UNII | 701M4TTV9O |
| DrugBank | DB01878 |
| KEGG | C06354 |
| ChEBI | CHEBI:41308 |
| ChEMBL | CHEMBL90039 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C13H10O |
| Molar mass | 182.217 g/mol |
| Appearance | White solid |
| Density | 1.11 g/cm3, solid |
| Melting point |
47.9 °C |
| Boiling point |
305.4 °C |
| Solubility in water | Insoluble |
| Solubility | Benzene, THF, ethanol, propylene glycol |
| Hazards | |
| MSDS | External MSDS by JT Baker |
| Main hazards | Harmful (XN) |
| NFPA 704 |
1
3
0
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| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Benzophenone is the organic compound with the formula (C6H5)2CO, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
Contents |
Benzophenone can be used as a photo initiator in UV-curing applications such as inks, imaging, and clear coatings in the printing industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions[1] .
Benzophenone can be prepared by the reaction of benzene with carbon tetrachloride followed by hydrolysis of the resulting diphenyldichloromethane,[2] or by Friedel-Crafts acylation of benzene with benzoyl chloride in the presence of a Lewis acid (e.g. aluminium chloride) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane with air.[3]
Benzophenone is a common photosensitizer in photochemistry. It crosses from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl radical.
Sodium reduces benzophenone to the deeply colored radical anion, diphenylketyl:
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products.[4] The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
Substituted benzophenones such as oxybenzone and dioxybenzone are used in some sunscreens. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy).[5]
p,p'-bis(N,N-dimethylamino)benzophenone or Michler's ketone has dimethylamino substituents at each para position.
The high-strength polymers PEEK, polyetherether ketones, are prepared from derivatives of benzophenone.