Characterization and catalytic behaviors of methylamine modified FAU zeolites

The methylamine (MA) modified FAU zeolites with 5.8 and 80 of silica alumina molar ratio were successfully prepared by the treatment of original FAU zeolites with MA. The obtained materials were investigated with diffuse reflectance infrared Fourier transform spectroscopy, X-ray diffraction, magic-angle spinning nuclear magnetic resonance, thermogravimetry, temperature-programmed desorption of CO2 and NH3 (CO2-TPD and NH3-TPD), nitrogen content analysis, and specific surface area analysis. The formations and thermal stabilities of different Si-N-C groups in the MA modified FAU zeolites were confirmed. The changing of aluminium species due to the interaction of MA and framework/extraframework aluminium (FAL/EFAL) in the modified samples was discovered. The acidity and basicity of the MA modified FAU zeolites were correlated to the hybrid aluminium species and variation of Si-N-C groups, respectively. The catalytic behaviors of the MA modified FAU zeolites were explored by Knoevenagel condensation reaction of benzaldehyde and malonic acid.