In addition and as also pointed out by , the CO 2 mass fraction increases, since the total oxidation is favored by the high temperatures. For a quantitative evaluation of the catalyst performance, the catalyst effectiveness factor η C 4 H 10 ,MA of the reaction from C 4 H 10 to MA is calculated for every individual particle in the fixed bed. The catalyst effectiveness factor is the ratio of the volume averaged reaction rate over the entire particle to the area averaged reaction rate at the catalyst surface: