Diketone

A diketone is an organic chemical compound which contains two carbonyl groups and the general structure RC (= O) -X -C (= O)- R ', while R, R' and X are carbon-containing radicals. The simplest diketones diacetyl ( H3C -CO -CO- CH3), acetylacetone ( H3C -CO- CH2 -CO- CH3) and acetonylacetone ( H3C -CO -CH2-CH2 -CO- CH3). Diketones are produced by oxidation of diols or hydroxy ketones.

System

The distance between the carbonyl shares the diketones in several classes. α -diketones such as diacetyl possess vicinal carbonyl groups. With β - diketones, carbonyls are separated by a methylene group; due to the strong electron-withdrawing effect of the carbonyls, the two hydrogen atoms on the methylene group between the two carbonyl groups are acidic (ie, under the influence of a base easily be split off ), this is an example of CH- acidity.

Reactions

Many reactions of diketones correspond to those of ketones. To reactivity and reaction behavior differ depending on the distance of the keto groups.

1,3 -diketones can easily enolize and form thermodynamically stable enols, eg acetylacetone is in a liquid state to 80 % in the enol form.

Nucleophilic addition reaction

Diketone nucleophile → Tetrahedral Carbonyladditionskomponente

• Hemiacetal alcohol acid (catalyst) ↔ Acetal water
• This is a carbonyl-protecting reaction.

Health

The EU Commission has stated in May 2005 that the diketone acetylacetone ( pentane -2 ,4 -dione ) is a genotoxic in vitro and in vivo chemical substance and therefore prohibited as a food additive.