[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.