A transient Mars-van Krevelen type kinetic model was developed for n-butane partial oxidation over vanadyl pyrophosphate (VPP) catalyst. The model validity was verified over a relatively wide range of redox feed compositions as well as higher reactor pressure (410?kPa). Oxygen and n-butane conversion increased with higher pressure while maleic anhydride (MA) selectivity decreased by as much as 20%. However, the overall MA yield was enhanced by up to 30%. High pressure maintains the catalyst in a higher oxidation state (as long as there is sufficient oxygen in the gas phase) and as a consequence, the catalytic activity is improved together with MA yield. High pressure also affects the redox reaction rates and activation energies. (c) 2012 Canadian Society for Chemical Engineering