Steady state and transient kinetic experiments for rational catalyst design: Differences of acrolein and methacrolein oxidation on mixed oxide catalysts

Acrolein (ACR) is oxidised with exceptionally high selectivity and activity on Mo-Voxides to give acrylic acid (AA). On the other hand heteropoly acids are the best catalysts for the partial oxidation of methacrolein (MAC). Our experiments have shown, that the oxidation of both starting materials is independent of the further oxidation of the corresponding acids and vice versa [1, 2]. This implies that the selective oxidation and the further oxidation proceed on different domains of the catalyst. Crosswise exchange of catalysts and reaction leads to considerably lower selectivities of both reactions. The variation of the Mo/V-ratio of heteropoly acid catalysts (HPA) has shown that catalysts of high selectivity generally exhibit low activity [3]. Due to this, variation of redox properties of the catalyst was restricted to mixed oxides. Alteration of the Mo/V-ratio of the mixed oxide has revealed that the different catalyst domains can be separately influenced, thus leading to an optimized selectivity