Purifying method of 2, 3-dichloropyridine

The invention discloses a purifying method of 2,3-dichloropyridine. The purifying method comprises the following steps of: mixing a crude 2, 3-dichloropyridine product, a treating agent and an organic solvent to form a liquid phase reaction system, and enabling the liquid phase reaction system to react at the temperature of 20-90DEG C; extracting a sample from the liquid phase reaction system, detecting the sample by using liquid chromatography under the detection conditions that the wavelength is 235nm and the volume ratio of methanol to water in a moving phase is 70:30, and when the content of 2,3,6-trichloropyridine in the sample is less than 0.5 percent, ending the reaction, or continuously reacting; and preparing a product solution after the reaction is ended, then cooling the product solution so that a crystallized product is sufficiently separated out, carrying out solid-liquid separation to obtain the crystallized product, adding the crystallized product to water so as to form a dispersed system, adju