Immobilized Molecular Catalysts

Sometimes the Van der Waals contact between the catalyst and support is used to immobilise catalysts that have been impregnated. The catalyst will be able to equilibrate between the two phases under the influence of this weak contact, which might result in significant leaching into solution. By altering the catalyst or the support to permit stronger interactions like hydrogen bonds or by experimenting with solvent characteristics, one can increase the stability of the supported catalyst. Complexes can be easily impregnated onto solid supports, although this method typically results in catalysts that are unstable. In the asymmetric epoxidation of 1,2-dihydronaphtalene with NaOCl, Mn(salen) immobilised on an Al-containing MCM-41 by impregnation demonstrated comparable catalytic activity and selectivity to the homogeneous catalyst.