General procedure for the synthesis of 2,4-difluorophenol from 2,4-difluorophenylboronic acid: arylboronic acid (1 mmol), 30% aqueous H2O2 solution (0.2 mL), ZnO nanocatalyst (5 mol%, sample ZnO-1), and 2 mL of water were stirred and mixed in a 50 mL round-bottomed flask at room temperature and under aerobic conditions. The reaction process was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the reaction mixture was diluted with 20 mL of water and extracted with ether (3 x 20 mL). The organic layers were combined, washed with brine and dried over Na2SO4. The solvent was removed by rotary evaporator under reduced pressure. The crude product was purified by silica gel (100-200 mesh) column chromatography (hexane/ethyl acetate, 9:1) to afford the target product 2,4-difluorophenol. The product structure was confirmed by 1H NMR and 13C NMR.
