Benzophenone

[citation needed] Carl Graebe of the University of Königsberg, in an early literature report from 1874, described working with benzophenone.

[5] Benzophenone can be used as a photo initiator in ultraviolet (UV)-curing applications[6] such as inks, imaging, and clear coatings in the printing industry.

Benzophenone prevents UV light from damaging scents and colors in products such as perfumes and soaps.

[10] A laboratory route involves the reaction of benzene with carbon tetrachloride followed by hydrolysis of the resulting diphenyldichloromethane.

Sodium-benzophenone ketyl is used in the purification of organic solvents, particularly ethers, because it reacts with water and oxygen to give non-volatile products.

[18] The sodium-benzophenone method is common since it gives a visual indication that water, oxygen, and peroxides are absent from the solvent.

Large scale purification may be more economical using devices which utilize adsorbents such as the aforementioned alumina or molecular sieves.

When excess alkali metal is present a second reduction may occur, resulting in a color transformation from deep blue to purple:[15] There are over 300 natural benzophenones, with great structural diversity and biological activities.

[22][23] The European Union permits it as a flavouring substance,[24] having established a Total Dietary Intake of 0.3mg/kg of body weight per day.

NFPA 704 four-colored diamond Health 1: Exposure would cause irritation but only minor residual injury. E.g. turpentine Flammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oil Instability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogen Special hazards (white): no code
The Haller–Bauer reaction occurs between a non-enolizable ketone and a strong amide base. In this prototypical example involving benzophenone, the tetrahedral intermediate expels phenyl anion to give benzamide and benzene as the organic products.
Addition of a solution of benzophenone in THF to a vial containing THF, sodium metal, and a stir bar, yielding the deep blue benzophenone anion radical. Playback speed 4x original recording. Notice that the stirbar is not Teflon-coated, which would be attacked by the ketyl.
A solvent pot containing dibutyl ether solution of sodium benzophenone ketyl, which gives it its purple color.