Benzophenone

• Diphenyl
• Diphenylmethanon
• Benzoylbenzene
• Phenyl ketone

Colorless prisms

Fixed

1.11 g · cm -3

49 ° C

305 ° C

• Slightly soluble in water (0.14 g · l -1)
• Slightly soluble in diethyl ether, ethanol, trichloromethane

Attention

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Benzophenone (IUPAC name: Diphenylmethanon ) is an organic compound, one of the groups of ketones and aromatics.

Production and representation

Benzophenone can either be synthesized by the reaction of benzene with carbon tetrachloride and subsequent hydrolysis of the resulting dichlorodiphenylmethane or by Friedel -Crafts acylation of benzene with benzoyl chloride in the presence of a Lewis acid (e.g. aluminum chloride).

Properties

Physical Properties

Benzophenone forms a colorless rhombic crystals, melting at 49 ° C. Under normal pressure, the compound boils at 305 ° C. The vapor pressure function is given by Antoine corresponding log10 (P) = A- ( B / ( T C )) ( P in bar, T in K) with A = 4.36238, B = 2116.372 and C = -93, 43 in the temperature range from 474 to 579 K, the main thermodynamic properties are listed in the following table:

Use

Benzophenone is used as photoinitiator in UV cure applications, such as inks and coatings in the printing industry. It protects scents and colors in products such as perfumes, soaps or plastic packaging from damage caused by UV radiation.

In the laboratory scale, it is used as an indicator for the drying of organic solvents with sodium application. This reduces benzophenone to the deep blue ketyl radical, which is stable in the absence of water and oxygen.

2-hydroxy -4-methoxy -benzophenone, a derivative of benzophenone, has been approved by the Cosmetics Directive as UV protection in sunscreens. It is referred to therein as " benzophenone -3" and can act allergenic.