Benzene acetylation

The ketones are readily prepared, for example, acetophenone from benzene, acetyl chloride (or acetic anhydride) and aluminium chloride by the Friedel and Crafts reaction ethyl benzyl ketones by passing a mixture of phenylacetic acid and propionic acid over thoria at 450° and n-propyl- p-phenylethylketone by circulating a mixture of hydrocinnamic acid and n-butyric acid over thoria (for further details, see under Aromatic Ketones, Sections IV,136, IV,137 and IV,141). 

During the first 2h of reaction, a decrease in AcOH conversion (from 48 to 43 %) for benzene acetylation at 523 K with an increase in selectivity to the monoacetylated product (from 80 to 90%) can be observed. The only problem involves the low catalyst activity 1.5 mmolh 1g 1 of acetophenone, which corresponds to a TOF value of 2.2 h-1. This means that less than 0.2 g of this acetylated arene can be produced per hour and per gram of catalyst under the operating conditions (i.e. 10 times less than in the liquid phase acetylation of anisole with AA). The kinetic study of the reaction shows an increase in the selectivity with the substrate/acetic acid ratio, but no increase in yield, an increase in acetic acid conversion with the reaction temperature with a significant decrease in selectivity due to a greater formation of diacetylated products.[62,63] HFAU and RE-FAU zeolites do... 

Acetophenone (1) Benzene + acetyl chloride (2) Ethyl benzene + 02 (3) By product of phenol production... 

On heating,both the acetyl and benzoyl acids lose carbon dioxide and the only product is the acetyl or benzoyl cyclopropane . The xetones tnus obtained readily form oximes, thus definitely proving that they are not oxygen ring compounds. Furthermore they have been connected with Ather cyclopropanes by the oxidation of the acetyl compound to cyclopropane monocarboxylic acid and by the formation of the benzoylcyclopropane from the chloride of this same acid and benzene . Acetyl cyclopropane has also been obtained by the following reaction,potas-... 

SYNONYMS 1-phenylethanone, acetophenon, acetylbenzene, benzene acetyl, benzoyl methide, ethanone 1 phenyl. 

Hydroxyanthranilic add, a product of tryptophan metabolism, is derivatized for gas chromatography as the N-acetyl methyl ester. Methylation with diazomethane first makes the O-methyl methyl ester after evaporation to dryness in a stream of nitrogen, the residue is acetylated in the dark in 50% benzene/acetyl chloride. The solution is again blown dry with nitrogen and dissolved in methanol for chromatography [36]. 

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