The selective oxidation of carbon monoxide in the presence of butane and maleic anhydride has been studied over platinum- and palladium-containing zeolites as well as palladium-on-silica (Pd/SiO2) catalysts. The results show that although a zeolite support is needed in many systems to effect a kinetic control to improve selectivity, thermodynamic control using Pd(approximately 2-4 PPM)/SiO2 is sufficient to give the desired selectivities in this system. In addition, a palladium-containing vanadium-phosphate catalyst was prepared that showed complete oxidation of carbon monoxide, conversion of butane to maleic anhydride, and no observable decomposition of the maleic anhydride.