Recovery by Column Chromatography

The monomeric catalyst fraction showed similar R[ values as the metathesis products, which complicated the chromatographic separation and recycling procedure. Immobilization of the ruthenium catalyst on a dendrimer was anticipated to facilitate the chromatographic separation. Indeed, the presence of multiple (polar) organometallic sites on the dendrimer periphery resulted in stronger adsorption interactions between the dendritic catalyst and the silica and thus a better separation from the product. Two types of dendritic catalysts were prepared in which 

We emphasize that in these systems the ruthenium catalysts are released from the dendritic support during the reaction, and the activities are therefore high. However, at the same time this release limits the application of this type of system to batch reactors. 

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