Phthalic anhydride is widely used in chemical, pharmaceutical, electronic, agriculture, coating, fine chemical and other industrial fields. Phthalic anhydride in our country is mainly used in the production of phthalate plasticizer. The chemical use phthalic anhydride is about 60% of the total consumption, paint and dye accounted for 25%, unsaturated resin and other products accounted for about 15%.