Chemical reaction engineering using molecularly imprinted polymeric catalysts

Enzymes play an important role as highly specific catalysts in biotechnology [J. Biotechnol. 66 (1998) 3; Hydrolases in Organic Synthesis, Wiley, New York, 1999] as well as in chemical reaction engineering [J. Biotechnol. 59 (1997) 11; Trends Biotechnol. 13 (7) (1995) 253]. However, the drawbacks of these biomaterials are poor durability and relatively high costs of production. Thus, the technique of molecular imprinting [Bio/Technology 14 (1996) 163; Angew. Chem. Int. Ed. Engl. 34 (1995) 1812; Anal. Commun. 36 (9) (1999) 327; J. Chromatogr. 781 (1997) 43] can be applied for generating much more stable polymeric mimics of biological enzymes. For this purpose, a stable transition state analogue (TSA) of a selected reaction must be chosen as template [Macromol. Rapid Commun. 19 (1998) 671; Curr. Opin. Chem. Biol. 3 (1999) 759]. The imprint of the TSA acts like a catalytically active centre. This binding site shows its catalytic effect by reducing the activation energy of the specific reaction. In the work presented here, molecularly imprinted catalytically active polymers have been generated and investigated in chemical reaction engineering processes, using batch reactors and continuously driven reactors equipped with these polymers. Parameters such as temperature, concentration of substrate or volume flow have been varied, reaction rates measured and kinetic data recorded. Based on this information, the rate constants of the reaction have been calculated, as well as the relative catalytic effects. It is demonstrated that imprinted polymer catalysts show obvious catalytic properties and can be used as an alternative for traditional catalyst materials.