# Oxidation of Methylene Groups to Carbonyl Groups

## Oxidation of Methylene Groups to Carbonyl Groups: Experimental Procedure

Oxidation of tetralin to 1-tetralone.

Fig.1

A mixture of 750 $mL$ acetic acid, 25 $g$ cobalt(II) acetate tetrahydrate and 30 $g$ cobalt(II) bromide hexahydrate in a 2-$L$ flask equipped with stirrer, thermometer and reflux condenser is vigorously stirred at 40$°C$. Oxygen is bubbled into the stirred mixture and a solution of 330 $g$ tetralin and 255 $g$ acetic acid anhydride is added dropwise within 30 $min$. The temperature of the reaction mixture has to be kept at 40$°C$. Oxygen is absorbed at a rate of 1,200 $mL$ per $min$. After an additional 30 $min$, the reaction is quenched with ice water and the product extracted with ether. The extract is washed with a cold solution of sodium carbonate, dried over magnesium sulfate and distilled. The yield is 62%.

In general, the preparation of carbonyl compounds in the laboratory is carried out either by oxidation or of primary or secondary alcohols.

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