Reverse-flow adsorption

Sulfur from H2S (Claus process) 96 Reverse-flow adsorptive reactor... 

FIGURE 36 Reverse-flow adsorption for the recovery of homogeneous catalysts (138-140). (For a color version of this figure, the reader is referred to the Web version of this chapter.)... 

REVERSE FLOW ADSORPTION TECHNOLOGY FOR THE RECYCLING OF HOMOGENEOUS CATALYSTS SELECTION OF SUITABLE ADSORBENTS... 

In actual homogeneous catalyzed processes, a homogeneous transition-metal catalyst is in equilibrium with its free transition-metal center and ligands. An excess of ligands is normally added [1] to decrease die amount of fiee transition-metal which negatively influences the selectivity of the reaction. Therefore, to apply Reverse Flow Adsorption, a combination of two ad rbents has to be used to reversibly adsorb the transition-metal center and the excess of ligands. 

To apply Reverse Flow Adsorption, a combination of two adsorbents has to be used for the reversible adsorption of a homogeneous transition-metal catalyst. The transition-metal center can be adsorbed by a suitable ligand immobilized onto a solid carrier, while the ligand is adsorbed by an immobilized transition-metal. Two groups of adsorbents have been studied, based on the HSAB predictions ( i the interactions with the Co(ll) transition-metal center or PPhj ligands ... 

To avoid the exchange of the immobilized transition-metal, for the transition-metal of the homogenous catalyst. Reverse Flow Adsorption requires two separate adsorption beds. The first bed for the recovery of the transition-metal center and the second bed for the ligand adsorption. 

---