Benzophenone

Benzophenone is an organic compound with the formula (C6H5)2CO, often abbreviated as Ph2CO. It is a widely used building block in organic chemistry, being the parent diarylketone.

Structure and properties

Benzophenone is a white, crystalline solid with a sweet, rose-like aroma. It is poorly soluble in water but is well soluble in common organic solvents. It features a carbonyl group (C=O) bonded to two phenyl groups. The molecular geometry around the carbonyl is trigonal planar, but the molecule is not planar.

Production

Benzophenone can be produced by several methods. The most common method is the Friedel-Crafts acylation of benzene with benzoyl chloride in the presence of a Lewis acid such as aluminium chloride.

Uses

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 is used in manufacturing perfumes and soaps, to enhance their scent. It is also used in the rubber industry to prevent ultraviolet light from damaging rubber products.

Health effects

Benzophenone can cause skin and eye irritation. Long-term exposure may lead to more serious health problems such as liver and kidney damage. It is classified as a possible human carcinogen by the International Agency for Research on Cancer.

See also

• Acetophenone
• Benzoyl chloride
• Benzoyl peroxide