| abstract |
Process for production of maleic anhydride comprising contacting n-butane-rich feed consisting essentially of n-butane, molecular oxygen and ballast gas with oxidation catalyst in a heat transfer medium-cooled, tubular reaction zone in which catalyst is graded in terms of reactivity such that reactivity increases to compensate for decreased reactant concentrations; removing effluent from the reaction zone; recovering maleic anhydride from the effluent; and recycling a major portion of the remaining effluent to the reaction zone. |