benzofenonen

Benzophenone, also known as diphenyl ketone, is an aromatic ketone with the formula (C6H5)2CO. Its IUPAC name is diphenylmethanone (also described as 1,1-diphenylethanone). The molecule consists of two phenyl rings bonded to a central carbonyl carbon. It is typically a white to off-white crystalline solid with a melting point around 49 °C and a boiling point near 305 °C. It is soluble in organic solvents and has very low solubility in water.

Production and structure-based properties underlie its uses. Industrially, benzophenone is mainly produced by Friedel–Crafts acylation of benzene with benzoyl chloride in the presence of a Lewis acid catalyst such as AlCl3, followed by workup and purification. The compound absorbs ultraviolet light, which predisposes it to act as a photosensitizer in certain chemical processes and as a UV-absorbing agent in some materials.

Applications. Benzophenone is widely used as a photoinitiator in UV-curing coatings and adhesives, where it helps generate free radicals upon exposure to UV light. It also serves as a UV absorber in plastics and coatings to limit degradation from sunlight. In the realm of cosmetics, derivatives of benzophenone (notably benzophenone-3, also known as oxybenzone) are common UV filters; benzophenone itself is primarily considered an industrial intermediate and a component in some fragrance and dye syntheses.

Safety and regulation. Handling benzophenone should follow general chemical hygiene practices; it can be an irritant to skin and eyes and may pose inhalation risks in powder form. As with many chemicals, regulatory status varies by region and application, and appropriate safety data sheets should be consulted for detailed hazard information.