Benzophenone

From Wikipedia, the free encyclopedia

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, ε_r, 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.

1 Synthesis and reactions
2 Benzyophenone ketyl radical
3 Derivatives
4 See also
5 References
6 External links
7 References
8 Gallery

[edit] Synthesis and reactions

Benzophenone can be prepared by the reaction of benzene with carbon tetrachloride followed by hydrolysis of the resulting diphenyldichloromethane.^[1]

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

Desiccant

[edit] References

^ Marvel, C. S.; Sperry, W. M., "Benzophenone". Organic Syntheses, Collected Volume 1, p. 95 (1941).

[edit] External links

Link page to external chemical sources.

[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.