Preparation of 3-fluoro-5-(trifluoromethyl)benzoic acid : In 100 ml four necked round bottom flask equipped with mechanical stirrer, thermometer, reflux condenser and an addition funnel, sodium hydroxide (6.35 g) and water (10 ml) was added and stirred for 15 mins at 25-35°C. To this, 3-fluoro-5- (trifluoromethyl)benzonitrile (10 g) was added and heated to 85-90°C. The reaction mass was stirred at 85-90°C for 2 hrs. After completion of reaction, the reaction mass was allowed to cool to 25-35°C. Then, the reaction mass was acidified with aqueous hydrochloric acid and stirred for 30 mins at 25-35°C. The solid formed was filtered, washed with water, suck dried and then dried under vacuum at 50-55°C for 6 hrs to get the title compound. Yield: 8 g.
