Cerium modified Y/SBA-15 composite molecular sieve catalyzed synthesis of n-butyl acetate

A novel Ce-Y/SBA-15 catalyst was prepared by modifying HY/SBA-15 microporous-mesoporous composite molecular sieve with cerium using the impregnation method. The characterization results from scanning electron microscopy/energy dispersive X-ray dispersive spectroscopy (SEM/EDS), transmission electron microscopy (TEM), and X-ray fluorescence (XRF) studies indicated that the Ce-modified catalyst maintained the microporous-mesoporous structure of Y/SBA-15. The Ce ions were found to be uniformly dispersed in the pores of the molecular sieve without aggregation. The results from pyrolysis coupled-Fourier transform infrared spectroscopy (Pyridine-FTIR) and temperature programmed desorption of ammonia (NH3-TPD) showed that the loading of cerium caused the hydroxyl group in the catalyst to display stronger Bronsted acidity. The efficiency of the modified Ce-Y/SBA-15 catalyst was evaluated by using it to catalyze the synthesis of n-butyl acetate. The optimal synthesis conditions were determined by orthogonal experiments. The highest esterification yield of 94.4% was obtained when the reaction time was 2.0 h, with acid/alcohol molar ratio of 1:1.2, and catalyst loading of 10 wt.%. The results in this study demonstrated that the loading of cerium and the structure of Y/SBA-15 microporous-mesoporous composite molecular sieve helped in improving the catalytic activity of this acidic catalyst.

HRTEM images of Y/SBA-15 and Ce-Y/SBA-15 (a) Y/SBA-15; (b) Ce-Y/SBA-15Figure optionsDownload as PowerPoint slide