Benzyl ethyl ketone

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). 

The dibenzyl ketone has a very high b.p. (ca. 200°/21 mm.) and this remains in the flask when the unsymmetrical ketone has been removed by distillation. The dialkyl ketone has a comparatively low b.p. and is therefore easily removed by fractionation under normal pressure acetone is most simply separated by washing with water. In this way methyl benzyl ketone (R = CHj), ethyl benzyl ketone (R = CHgCH,) and n-propyl benzyl ketone (R = CHjCHjCH,) are prepared. By using hydrocinnamic acid in place of phenylacetic acid ... 

Ethyl benzyl ketone. Use 204 g. of phenylacetic acid (m.p. 77°) and 333 g. (335 -5 ml.) of propionic acid (b.p. 139-141°), but omit the extraction with benzene when working up the distillate. Distil the dried... 

Using the same procedure the following ketones may be obtained in similar yields ethyl benzyl ketone from phenylacetic acid and propionic acid, methyl 8-phenylethyl ketone from hydrocinnamic acid and acetic acid, and ethyl /3-phenylethyl ketone from hydrocinnamic acid and propionic acid. 

As examples of ketones within the above formula, mention may be made of ethyl benzyl ketone, methyl para-isopropylbenzyl ketone, methyl meta-io y ketone, methyl butyl ketone, methyl phenylisopropyl ketone, methyl benzyl ketone and methyl para-dimethoxybenzyl ketone. 

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