Purification process of fipronil

The invention relates to a fipronil purification process, and belongs to the technical field of fipronil preparation, and the fipronil purification process comprises the following steps: preparing a catalytic component; the preparation method comprises the following steps: by using dichloromethane, 5-amino-3-cyano-1-(2, 6-dichloro-4-trifluoromethylphenyl) pyrazole and a catalytic component, obtaining a crude product; adding the crude product, absolute ethyl alcohol and activated carbon into a first reaction kettle, raising the temperature in the kettle to 70-80 DEG C, stirring and dissolving, carrying out reflux reaction for 1-1.5 hours, carrying out filter pressing on the material liquid in the first reaction kettle by using nitrogen through a filter press and a filter, transferring the material liquid into a second reaction kettle, and carrying out atmospheric distillation and recrystallization to obtain the product with the purity of 98% or above, compared with a traditional production process, two purific