Significant porosity effects in carbon based SILP chiral catalysts

Abstract

The immobilization of the chiral complex RhDuphos onto different carbon materials using the SILP methodology (Supported Ionic Liquid Phase) has been investigated with the double purpose of preserving the steric configuration of the Rh complex and of increasing, respect to conventional biphasic systems, the interphase between the ionic liquid and the substrates. The prepared SILP catalysts have been tested in the liquid-phase hydrogenation of methyl 2-acetamidoacrylate (MAA) at room temperature and 5.5 bar H2, using water as solvent. All catalysts showed high activity, although low enantioselectivity was observed for the SILP catalysts with the smaller amount of ionic liquid loaded. Upon increased IL loading, higher ee values were obtained. Ionic liquid leaching from the SILP catalyst was observed while the Rh loss was low in all cases. The textural properties of the carbon materials used as support have shown a very significant influence in the catalytic properties of the SILP catalysts, being more interesting supports with mesoporosity.