Reduction of acrylic acid in the production of maleic anhydride

摘要

An improved process for the production of maleic anhydride by the catalytic oxidation of n-butane. Maleic anhydride is produced by reacting n-butane gas with oxygen gas or an oxygen-containing gas, in the presence of a vanadium phosphorus oxide catalyst. A trialkyl phosphite or trialkyl phosphate component is continuously added to the gases in an amount of from about 0.5 ppm to about 4 ppm by weight of elemental phosphorus in the trialkyl phosphate or trialkyl phosphite component. Heat is applied to the gases at a temperature of from about 400° C. to about 440° C. while maintaining a maximum temperature of gases present in the reaction of about 480° C. A simultaneous conversion of n-butane to maleic anhydride of about 84% or more and a conversion of n-butane to by-product acrylic acid of about 1.5% or less is achieved.