Comparison of the catalytic activity of MOFs and zeolites in Knoevenagel condensation

[EN] The catalytic behavior of metal-organic-frameworks (MOFs) CuBTC and FeBTC was investigated in Knoevenagel condensation of cyclohexane carbaldehyde and benzaldehyde with active methylene compounds and compared with zeolites BEA and TS-1. High yields were achieved over the CuBTC catalyst in the Knoevenagel condensation involving malonitrile, especially at a relatively low reaction temperature (80 degrees C); no leaching of the active phase was evidenced. In contrast, zeolites were not active under such reaction conditions. We propose an activation of malonitrile on a pair of adjacent Cu ions to explain the high catalytic activity of CuBTC with respect to conventional catalysts. Compared with CuBTC, zeolites exhibited usually lower selectivities, which is ascribed to a high acid strength of their active sites promoting consecutive reactions.The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 228862. P.N., M. H., and J.C. thank the Czech Grant Agency for the financial support (Centre of Excellence - P106/12/G015).Opanasenko, M.; Dhakshinamoorthy, A.; Shamzhy, M.; Nachtigall, P.; Horacek, M.; García Gómez, H.; Cejka, J. (2013). Comparison of the catalytic activity of MOFs and zeolites in Knoevenagel condensation. Catalysis Science and Technology. 3(2):500-507. https://doi.org/10.1039/c2cy20586fS5005073