Multiphase catalysts in selective processes

The review deals with the relationships of the activity and selectivity of multicomponent catalysts with their phase composition. In the partial oxida tion of olefins, an increase in the number of phases often leads to an incr ease in selectivity. Various physical techniques suggest that this is due t o the occurrence of different steps of the complex oxidation on different p hases. In the case of catalysts for the partial oxidation of methane into e thylene, formaldehyde, and methanol, different steps of the process also oc cur on different phases. In this case, the process is initiated on the soli d catalyst and subsequent steps yielding reaction products occur in the gas phase. In carbon dioxide reforming of methane and Fischer-Tropsch synthesi s, different steps of the complex processes also occur on different phases.