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|Section2= |Section3= |Section7= |Section8= }} Maleic anhydride is an organic compound with the formula C2H2(CO)2O. It is the acid anhydride of maleic acid. It is a colorless or white solid with an acrid odor. It is produced industrially on a large scale for applications in coatings and polymers. ==Production== Maleic anhydride was traditionally produced by the oxidation of benzene or other aromatic compounds. As of 2006, only a few smaller plants continue to use benzene. Instead, most maleic anhydride is produced by vapor-phase oxidation of ''n''-butane. The overall process converts the methyl groups to carboxylate and dehydrogenates the backbone. The selectivity of the process reflects the robustness of maleic anhydride, with its conjugated double-bond system. 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 igniting. Vanadium pentoxide and molybdenum trioxide are the catalysts used for the benzene route, whereas vanadium phosphate is used for the butane route.〔 :C4H10 + 3.5 O2 → C2H2C2O3 + 4 H2O ∆H = -1236 kJ/mol The main competing process entails full combustion of the butane, a conversion that is twice as exothermic as the partial oxidation. Industrial production of maleic anhydride is achieved by integration of following unit processes: catalyst packed bed reactor, adsorption tower, maleic acid reactor, distillation column. The reactant stream of n-butane and air mixture enters the packed bed reactor at a temperature of 120-150 °C and a pressure of 2-3 atm. The product stream is then sent to a packed bed adsorption column, where the condensable maleic anhydride reacts with the water stream to give maleic acid and the non-condensable are sent for fuel gases treatment. The condensable stream from adsorption tower is sent to a maleic acid reactor, where maleic acid is again converted back to the anhydride. This product stream from reactor is sent to distillation column to obtain pure maleic anhydride as product. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Maleic anhydride」の詳細全文を読む スポンサード リンク
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