Immobilized Molecular Catalysts

Van der Waals contact between the catalyst and support is occasionally used to immobilise catalysts that have been impregnated. It will be possible for the two phases to equilibrate the catalyst under the influence of this weak interaction, which could result in significant leaching into solution. By altering the catalyst or the support to allow for stronger interactions like hydrogen bonds or by experimenting with solvent properties, the stability of the supported catalyst can be increased. Complexes can be easily impregnated onto a solid support, however the catalysts it often produces are unstable. Similar catalytic activity and selectivity to the homogeneous catalyst were demonstrated by Mn(salen) immobilised on an Al-containing MCM-41 during the asymmetric epoxidation of 1,2-dihydronaphtalene with NaOCl.