A typical procedure for oxidation of 4-nitrobenzylalcohol: a mixture of NaNO2(1035 mg
, 15mmol) and 4-nitrobenzyl alcohol (5 mmol) in acetic anhydride (2 mmol) was stirred. A spontaneous exothermic reaction took place which was controlled by cooling the mixture in ice. After completion of the reaction (TLC), the product was extracted with ether (2 10 ml). Removal of the solvent under reduced ded crude 4-nitrobenzaldehyde which was further by column chromatography(petroleum ether–ethyl acetate, 9 : 1).
Reference:J. Chem. Soc., Perkin Trans. 1, 2000,3559–3560