Method for purifying folic acid

The invention provides a method for purifying folic acid. The method comprises the following steps: first, adding folic acid crude product into an organic solvent of a certain weight ratio, uniform stirring, lowering the temperature of the system to 0~20 DEG C; then slowly dropwise adding a certain amount of thionyl chloride to the folic acid turbid liquid, continuing to stir until the solid is completely dissolved, then stirring for 1~3 hours; finally, filtering the dissolved solution to remove insoluble matter, subjecting the organic solvent to vacuum distillation to remove most of the solvent, recycling the solvent, cooling to certain temperature, slowly stirring for 1~3 hours, performing crystallization, and performing filtration to obtain purified folic acid. The method for purifyingfolic acid provided by the invention is simple in operation and low in cost, and effectively reduces the generation of wastewater in folic acid purification, and is suitable for requirements of industrialization to environmen