|Jmol-3D images||Image 1|
|Molar mass||182.22 g mol−1|
|Melting point||48.5 °C; 119.3 °F; 321.6 K ()|
|Boiling point||305.4 °C; 581.7 °F; 578.5 K ()|
|Solubility in water||Insoluble|
|Solubility in organic solvents||1 g/ 7.5 mL in ethanol
1 g/ 6 mL in diethyl ether
|MSDS||External MSDS by JT Baker|
|Main hazards||Harmful (XN)|
|Flash point||110 °C; 230 °F; 383 K|
| (what is: / ?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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.
Benzophenone can be prepared by the reaction of benzene with carbon tetrachloride followed by hydrolysis of the resulting diphenyldichloromethane, 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.
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.
Benzophenone radical anion
Sodium reduces benzophenone to the deeply colored radical anion, diphenylketyl:
- Na + Ph2CO → Na+Ph2CO·−
Although inferior in safety and effectiveness relative to molecular sieves, this ketyl is used in the purification of organic solvents, particularly ethers, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it accelerates the reaction of the sodium with 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.
Commercially significant derivatives
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).
The high-strength polymer PEEK is prepared from derivatives of benzophenone.
- Merck Index, 11th edition, 1108
- Dorman, Gyorgy; Prestwich, Glenn D. (1 May 1994). "Benzophenone Photophores in Biochemistry". Biochemistry 33 (19): 5661–5673. doi:10.1021/bi00185a001.
- Marvel, C. S.; Sperry, W. M. (1941), "Benzophenone", Org. Synth.; Coll. Vol. 1: 95
- Hardo Siegel, Manfred Eggersdorfer "Ketones" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, 2002 by Wiley-VCH, Wienheim. doi:10.1002/14356007.a15_077
- Williams, D. B. G., Lawton, M., "Drying of Organic Solvents: Quantitative Evaluation of the Efficiency of Several Desiccants", The Journal of Organic Chemistry 2010, vol. 75, 8351. doi: 10.1021/jo101589h
- W. L. F. Armarego and C. Chai (2003). Purification of laboratory chemicals. Oxford: Butterworth-Heinemann. ISBN 0-7506-7571-3.
- L. M. Harwood, C. J. Moody and J. M. Percy (1999). Experimental Organic Chemistry: Standard and Microscale. Oxford: Blackwell Science. ISBN 978-0-632-04819-9.
- Knowland, John; McKenzie, Edward A.; McHugh, Peter J.; Cridland, Nigel A. (1993). "Sunlight-induced mutagenicity of a common sunscreen ingredient". FEBS Letters 324 (3): 309–313. doi:10.1016/0014-5793(93)80141-G. PMID 8405372.
Toluene is refluxed with sodium and benzophenone to produce dry, oxygen-free toluene.