Application: Maleic anhydride is mainly used as raw material for the production of unsaturated polyester resin, alkyd resin, pesticide malathion, high-efficiency and low-toxicity pesticide 4049, and long-acting iodamine. It is also a comonomer of paint, maleic rosin, polymaleic anhydride, maleic anhydride-styrene copolymer, and an organic chemical raw material for the production of ink additives, paper additives, plasticizers, tartaric acid, fumaric acid, tetrahydrofuran, etc.