The invention discloses a synthesis method of an insecticide teflubenzuron and an intermediate 2,6-difluorobenzamide of the insecticide teflubenzuron, belonging to the field of pesticides. The synthesis method comprises the following steps: step 1, preparation of 2,6-dichlorobenzylidene
chloride: preparing turbid liquid of dichlorotoluene and
phosphorus pentachloride, introducing
chlorine gas, layering materials by utilizing a gas-liquid separator, collecting a crude product, and rectifying the crude product to obtain the 2,6-dichlorobenzylidene
chloride; and 2, preparation of 2,6-dichlorobenzonitrile: mixing 2,6-dichlorobenzylidene
chloride,
acetic acid,
zinc chloride,
hydroxylamine hydrochloride and
sodium acetate, carrying out heating for a
reflux reaction, conducting cooling, stirring,filtering and
drying successively after the reaction is completed so as to obtain 2, 6-dichlorobenzonitrile. By adopting a one-pot method, a reaction
route is shortened, total yield is increased to 67.3% from conventional 55.4%, and cost is greatly reduced.