Dibenzyl ketone, or 1,3-diphenylacetone, is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. T ...

composed of two

benzyl In organic chemistry, benzyl is the substituent or molecular fragment possessing the structure . Benzyl features a benzene ring () attached to a methylene group () group. Nomenclature In IUPAC nomenclature, the prefix benzyl refers to a substi ...

groups attached to a central

carbonyl In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups. A compound containi ...

group. This results in the central carbonyl carbon atom being electrophilic and the two adjacent carbon atoms slightly nucleophilic. For this reason, dibenzyl ketone is frequently used in an aldol condensation reaction with

benzil Benzil (i.e. Bz2, systematically known as 1,2-diphenylethane-1,2-dione) is the organic compound with the formula ( C6H5 CO)2, generally abbreviated ( PhCO)2. This yellow solid is one of the most common diketones. Its main use is as a photoinitia ...

(a dicarbonyl) and base to create tetraphenylcyclopentadienone. Vera Bogdanovskaia is credited with the classification of dibenzyl ketone.

Preparation

One method is where phenylacetic acid is reacted with acetic anhydride and anhydrous

potassium acetate Potassium acetate (CH3COOK) is the potassium salt of acetic acid. It is a hygroscopic solid at room temperature. Preparation It can be prepared by treating a potassium-containing base such as potassium hydroxide or potassium carbonate with acetic ...

and refluxed for two hours at 140−150 °C. The mixture is distilled slowly so that the distillate is mostly acetic acid.

Carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...

is released in this reaction. The resultant liquid is a mixture of dibenzyl ketone and minor impurities. Heating the mixture above 200−205 °C leads to resinification with a decrease in the yield of the ketone. A more convenient method is adding a solution of phenylacetic acid in dry dichloromethane dropwise to a solution of DCC and DMAP in dry dichloromethane, then stirring for 24 hours. The resulting reaction mixture is filtered to remove

dicyclohexylurea Dicyclohexylurea is an organic compound, specifically, a urea. It is the byproduct of the reaction of dicyclohexylcarbodiimide with amines or alcohols. It may be prepared by the reaction of cyclohexylamine Cyclohexylamine is an organic compound, ...

, evaporated to dryness, then purified by column chromatography on silica gel. This method is also used for substituted derivatives of phenylacetic acid, such as 4-bromophenylacetic acid, to prepare the corresponding symmetric bisbenzyl ketone derivative (in this case 1,3-bis(4-bromophenyl)acetic acid).

References

Dibenzyl ketones Benzyl compounds {{ketone-stub