3,4,5,6-tetrahydrophthalic anhydride is referred to as △ 1 for short , and it is an intermediate of the insecticide pyrethrin. Can be used as a modifier of alkyd resin, epoxy resin curing agent, unsaturated polyester resin, pesticides and pharmaceutical raw materials for light-colored or air-drying alkyd resin, curing agent of light-stable unsaturated polyester and epoxy resin, as well as production of putty resin, PE resin, solvent-free paint, antifouling paint, HF-grade insulating paint, room temperature quick-drying or anaerobic adhesive, EPS plasticizer, pesticides, tetramethrin