Process for the production of maleic anhydride

A process for the production of maleic anhydride, which comprises:

• reacting a hydrocarbon in gaseous state with an oxygen-containing gas in the presence of a catalyst in a reactor to produce an effluent reaction gas containing maleic anhydride;
• recovering maleic anhydride from the reaction gas;
• recovering at least 90% of the unreacted hydrocarbon from the gas remaining after recovery of the maleic anhydride with the production of an exhaust gas;
• and
• returning the hydrocarbon thus recovered to the reactor for re-use;
• wherein said reaction is effected under the conditions such that the hydrocarbon concentration X (vol %) and oxygen concentration Y (vol %) in all the gases to be fed into the reactor, the hydrocarbon conversion Z (%) in the reactor and the oxygen concentration W (vol %) in all the effluent gases from the reactor satisfy the following relationships:
• Y>20,
• X+Y≦70,
• 1≦Y/X≦5, and
• 20(Y−10)/X≦Z≦25Y/X or 2≦W≦10.