Method for synthesizing 2-amino-5-chlorine-toluenesulfonic acid

The invention relates to a method for synthesizing 2-amino-5-chlorine-toluenesulfonic acid. The method is characterized in that a reactant 2-nitro-5-chlorine-toluenesulfonic acid is generated througha catalytic hydrogenation reaction in a three-phase system composed of gas-phase hydrogen, a liquid-phase solvent and a solid-phase nickel catalyst. The method specifically includes the following steps of putting 15-20% by mass of 2-nitro-5-chlorine-toluenesulfonic acid, 8-10% by mass of a catalyst, 0.2-0.4% by mass of a dechlorination inhibitor and 70-76% by mass of a solvent into a reaction kettle; starting stirring, and continuously introducing high-purity hydrogen into the reaction kettle to ensure that the internal pressure of the reaction kettle is constant, wherein the reaction temperature is controlled at 75-85 DEG C, the pressure is 2.5-3.5 MPa, the rotation speed during stirring is 300-450 rpm, and the reaction time is 30-50 min. The process flow is simplified, the reaction timeis short, the product yiel