Patent ID: 7619099

Claim:
A process for the production of maleic anhydride which comprises reacting n-butane gas with oxygen gas or an oxygen-containing gas, in the presence of a vanadium phosphorus oxide catalyst; continuously adding at least one trialkyl phosphite or trialkyl phosphate component 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, based on the total amount of the n-butane gas and oxygen gas or an oxygen-containing gas, while applying heat to the gases at a temperature of from about 400° C. to about 440° C. and maintaining a maximum temperature of gases present in the reaction of about 480° C., to simultaneously achieve a 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.