Phenylacetone

Colorless liquid

Liquid

1.01 g · cm -3 ( 20 ° C)

-15 ° C

216 ° C

• Practically insoluble in water
• Soluble in ethanol, diethyl ether, benzene and xylene

1.5165

Template: Infobox chemical / molecular formula search available

Phenylacetone is a colorless to pale yellow liquid with a strong, characteristic odor, which is used in the chemical and pharmaceutical industries.

Use

Phenylacetone is used for the synthesis of pesticides and pharmaceuticals. Examples are diphacinone ( a rat poison ) or amphetamine ( reductive amination). Because of its potential use in the synthesis of various amphetamines manufacture and the sale requires a permit.

Representation

Phenylacetone ( 4) can be written in different ways. The most economical method appears I, ie the Dakin -West reaction of phenylacetic acid (1 ) and acetic anhydride ( 2) with base catalysis. The enolate of the mixed anhydride attack another molecule 2 splits from acetate and the resulting β - keto-acid is decarboxylated to 4 3 Another method (II ) is used as Acetylquelle acetates of divalent metals, especially of lead. The reaction of methyl lithium with the lithium salt of phenylacetic acid represents (III) a further elegant route to 4, although in this case the half of MeLi for the deprotonation of 1 has to be applied.

Further syntheses that do phenylacetic without the monitored substance, are indeed possible, but because of the price or the toxicity of individual starting materials or due to low yields can only be performed on a laboratory scale. Among other things, there is the possibility of benzene with chloroacetone in a Friedel -Crafts acylation implement (IVa) or acetone, even with benzene radical to combine (IVb ); this takes the manganese (III ) acetate is the limiting reagent. Ketones can be prepared by the reaction of organometallic reagents with nitriles: In our case, this means you can either methyl aluminum (or Methlymagnesiumhalogenid ) can act on benzyl cyanide (Va) or benzyl magnesium bromide on the other hand, acetonitrile ( Vb); in both cases, the hydrolysis of the intermediate imine, the ketone 4 is also interesting to the oxidation of α -methyl styrene with thallium ( III) salts in methanol ( VI): After the addition to the double bond splits Tl ( I) from and on the intermediate carbocation leads to a sigmatropic rearrangement. The resulting dimethyl ketal is then hydrolysed under acid catalysis.

Terms of Use

Because of its suitability as a raw material in the Methamphetaminsynthese phenylacetone heard in the EU and Switzerland to the category I of the monitored chemicals following the Precursors Monitoring Act. This means the production, trade, import and export without permission is punishable by law.

Swell

• Ketone
• Aromat