Preparation method of 2-chloro-5-chloromethylpyridine

The invention relates to the field of chemical synthesis, particularly a preparation method of 2-chloro-5-chloromethylpyridine. The preparation method comprises the following step: carrying out cyclization reaction on 2-chloro-2-chloromethyl-4-cyanobutyraldehyde and cyanuric chloride to obtain the 2-chloro-5-chloromethylpyridine. The preparation method provided by the invention has the advantages of low production cost, high product quality, high yield and the like. Besides, the byproduct sodium cyanurate of the preparation method can be treated to prepare thetrichloroisocyanuric acid superior product, thereby further enhancing the economic benefits.