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Maleic anhydride was traditionally manufactured by the oxidation of benzene or other aromatic compounds. As of 2006, only a few smaller plants continue to use benzene; due to rising benzene prices, most maleic anhydride plants now use n-butane as a feedstock.

In both cases, benzene and butane are fed into a stream of hot air, and the mixture is passed through a catalyst bed at high temperature. The ratio of air to hydrocarbon is controlled to prevent the mixture from catching on fire. Vanadium pentoxide and molybdenum trioxide are the catalysts used for the benzene route, whereas vanadium and phosphorus oxides are used for the butane route.

Maleic anhydride is a highly reactive chemical intermediate with present and potential uses in practically every field of industrial chemistry. Maleic anhydride series products are essential to the production of a multitude of resins and plastics, agricultural and industrial chemicals, petroleum additives, paper sizing, water treatment chemicals, epoxy curing agents, artificial sweeteners, flavor enhancers, hair sprays, pharmaceuticals and copolymers. Its biggest single use is in the manufacture of unsaturated polyester resins.