Abstract
The porosity and acidity of three commercial FAU Y zeolites (including the original HY-2.6 and dealuminated HY-15/-30 zeolites) were studied comprehensively using nitrogen (N2) physisorption, and mercury (Hg) porosimetry, ammonia temperature-programmed desorption (NH3-TPD) and pyridine Fourier transform infrared (pyridine-IR) analyses. The combined N2 physisorption and Hg porosimetry is a useful tool to evaluate the hierarchical mesoporosity in the dealuminated samples, revealing that HY-15 and HY-30 possess >50% open mesoporosity in the mesopores range of 5–10 nm. The acidity of the dealuminated Y zeolites has been reduced significantly in comparison to that of the original HY-2.6, e.g. Bronsted acidity decreased by ca. 69 folds by dealuminating HY-2.6 to HY-30. Catalytic results of Fischer esterification of methanol with carboxylic acids and aldol condensation of benzaldehyde with 1-heptanal have evidenced that the critical role of mesoporosity of the dealuminated Y zeolites in liquid-phase reactions. For example, in the esterification of lauric acid with methanol, HY-15 and HY-30 with hierarchical mesopores showed better catalytic activity (i.e. conversion of lauric acid: 7.9% and 24.5%, respectively) than HY-2.6 (4.0%). The analysis of the catalytic results along with the acidic property suggests that the acidity is less influential than the porosity of zeolite catalysts. Results from this study allow us to explain the origin of the high activity of zeolites with mesoporosity in the liquid-phase catalysis.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
