Preparation method of 2-cyano-3-fluoro-5-trifluoromethylpyridine

The invention discloses a preparation method of 2-cyano -3-fluorine -5-trifluoromethylpyridine, and belongs to the field of organic chemistry. The method comprises the following steps: by taking 2-cyano- 3-chloro -5-trifluoromethylpyridine as a raw material, carrying out heating reaction in a polar aprotic solvent in the presence of a fluorinating reagent and a phase transfer catalyst to obtain a2-cyano- 3-fluoro -5-trifluoromethylpyridine crude product; and after filtering and desalting, carrying out reduced pressure distillation to obtain the 2-cyano -3-fluoro-5-trifluoromethylpyridine withthe content of more than 99%. The method provided by the invention has the advantages of high yield, simple wastewater treatment and less three wastes, and the yield of 2-cyano -3-fluoro- 5-trifluoromethylpyridine can reach 95%. 本发明公开了一种2-氰基-3-氟-5-三氟甲基吡啶的制备方法，属于有机化学领域。该方法以2-氰基-3-氯-5-三氟甲基吡啶为原料，在在氟化试剂和相转移催化剂存在下，极性非质子溶剂中升温反应得到2-氰基-3-氟-5-三氟甲基吡啶粗品。过滤除盐后，减压蒸馏得到含量99％以上2-氰基-3-氟-5-三氟甲基吡啶。本发明收率高、废水处理简单，三废少，2-氰基-3-氟-5-三氟甲基吡啶收率可达到95％