Benzophenone
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| Benzophenone | |
|---|---|
| |
| General | |
| Systematic name | Benzophenone |
| Other names | diphenylmethanone phenyl ketone diphenyl ketone benzoylbenzene |
| Molecular formula | C13H10O |
| SMILES | O=C(C2=CC=CC=C2)C1=CC=CC=C1 |
| Molar mass | 182.217 g/mol |
| Appearance | white solid |
| CAS number | [119-61-9] |
| Properties | |
| Density and phase | 1.11 g/cm3, solid |
| Solubility in water | insoluble |
| Other solvents | benzene, THF, ethanol, propylene glycol |
| Melting point | 47.9 °C |
| Boiling point | 305.4 °C |
| Dipole moment | |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | flammable |
| NFPA 704 | |
| Flash point | ? °C |
| R/S statement | R: ? S: ? |
| RTECS number | ? |
| Supplementary data page | |
| Structure and properties | n, εr, etc. |
| Thermodynamic data | Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Related compounds | benzil, acetophenone |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references | |
Benzophenone is the organic compound with the formula (C6H5)2CO, generally abbreviated Ph2CO. Substituted benzophenones such as oxybenzone and dioxybenzone are used in sunscreen.
Contents |
[edit] Synthesis and reactions
Benzophenone can be prepared by the reaction of benzene with carbon tetrachloride followed by hydrolysis of the resulting diphenyldichloromethane.<ref>Marvel, C. S.; Sperry, W. M., "Benzophenone". Organic Syntheses, Collected Volume 1, p. 95 (1941).</ref>
Benzophenone is commonly used as a photosensitizer in photochemistry. Its triplet is readily quenched by oxygen, and can also react with a suitable hydrogen donor to for a ketyl radical.
[edit] Benzyophenone ketyl radical
Sodium is commonly used as a desiccant to purify solvents by reacting with water to give the hydroxide, which is nonvolatile:
- Na + H2O → NaOH + 1/2 H2
The main problem with the use of Na as a desiccant (below its melting point) is associated with the slow rate of reaction between a solids and a solution. When however, the desiccant is soluble, the speed of drying is much higher. Benzophenone is often used to generate such a soluble drying agent,. An advantage to this application is the intense blue color of the ketyl radical anion. Thus, benzophenone/Na can be used as an indicator of air-free and moisture-free conditions in the purification of solvents by distillation.
[edit] Derivatives
- p,p'-bis(N,N-dimethylamino)benzophenone or Michler's ketone has dimethylamino substituents at each para position.
[edit] See also
[edit] References
<references/>
[edit] External links
[edit] References
- Merck Index, 11th Edition, 1108.
- Anion Radicals
[edit] Gallery
A bottle of benzophenone by Lancaster. |
Toluene is refluxed with sodium and benzophenone to produce dry, oxygen-free toluene. |
The mixture is still not blue yet indicating that the reaction is not complete. |
The intense blue coloration due to the benzophenone ketyl radical shows that the toluene is considered free of air and moisture. |
After the toluene has been thoroughly dried by the sodium and benzophenone, it is distilled at atmospheric pressure under a slight positive pressure of nitrogen to prevent contamination by air into the receiving Schlenk flask. |
