Replacement of hydrogen by the hydroxyl group

In broad terms it is only in special cases that the oxidation of hydrocarbons to primary or secondary alcohols is of practical importance. One such case is oxidation of toluene and its derivatives to the corresponding benzyl alcohols, by e.g., manganese dioxide, lead dioxide, lead tetraacetate, or Caro s acid. It is advantageous to use lead tetraacetate in glacial acetic acid solution since then the alcohol formed is protected by esterification against further oxidation. 

Preparation of benzyl acetate from toluene 216 Lead tetraacetate (120 g) and toluene (40 g) are boiled for 4 h in glacial acetic acid (200 ml previously distilled from potassium permanganate). Then most of the acetic acid is distilled off and the residue is treated with water and extracted with ether. The extract is washed with sodium hydrogen carbonate solution and dried then distillation in a vacuum affords the crude benzyl acetate (7.5 g). 

For the preparation of lead tetraacetate, pure red lead (200 g) is stirred in very small portions into glacial acetic acid (1 1) at 80° without allowing the temperature to rise any higher. Then the solution is filtered if necessary on cooling, it affords lead tetraacetate in colorless needles, which are filtered off, washed with a little glacial acetic acid, and dried in a desiccator. 

As further examples may be cited the conversion of acenaphthene into 

1- acenaphthenol by Marquis220 using lead dioxide in glacial acetic acid and by Casow221 using red lead in the same solvent. 

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