Preparation method of benzidine_Kain Industrial Additive

background and overview[1] toluidine can be used as a pharmaceutical synthesis intermediate. preparation[1] the specific steps for the preparation of benzidine are as follows: in a 500ml four-neck flask equipped with a thermometer, reflux condenser and stirrer, add 350g 30 mass% fuming sulfuric acid (1.31molso3), and keep the internal temperature at 30°c to 40 ℃.…