Zeolites comparison with MOFs

The simplicity of synthesis with no necessity for the use of organic templates and other structure-directing agents, and for high-temperature calcinations to remove the template makes MOFs competitive in comparison with zeolites. The principles of the modular chemistry and methodology of synthesis of MOFs and, in general, porous coordination polymers (PCPs) are presented in a few very good recent reviews [23-25]. The synthesis and properties of the new JUC family of MOFs (JUC is the abbreviation of Jilin University China) is the focus of the review [26]. 

MIL-53 materials provide a convenient model for comparison with traditional sorbents with similar geometric characteristics, such as activated charcoals and zeoUtes. The specific surface area estimated for MIL-53,1100 mVg (BET method), is similar to the average value for nanocarbon materials and exceeds that for zeolites. The framework of MIL-53 comprises unidimensional channels of 8.5 A in diameter, which is similar to the pore diameter in zeolites (6-12 A) and smaller than that in the IRMOF series, including MOF-5 (12-15 A). At the same time, the hydrogen adsorption capacity of MIL-53 is somewhat higher than that of the zeolite CaX (2.19wt.%, Table 2) and activated charcoals (2.15 wt.%) [179]. It is possible that this parameter is affected by the channel geometry, because zeolites more often have a 3D channel system, as opposed to the unbranched unidimensional channels in MIL-53. However, additional experiments on the adsorption mechanism are required to draw more definitive conclusions. 

Finally, MOFs have been recently reported for Pechmann reaction specifically Cu3(BTC)2 and Fe(BTC) (where BTC is benzene tricarboxylic acid) were investigated in the condensation between different phenols and ethyl acetoacetate. Opanasenko et al. studied the comparison of the catalytic performance of MOFs with laige-pore zeolites—BEA and USY... 

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