Direct synthesis of hierarchical USY zeolite for retardation of catalyst deactivation. (22nd October 2016)

• Record Type: Journal Article
• Authors: Liu, Baoyu; Xie, Kaihong; Oh, Su Cheun; Sun, Dalei; Fang, Yanxiong; Xi, Hongxia
• Is Part Of: Chemical engineering science. Volume 153(2016)
• Page Start: 374
• Page End: 381
• Publication Date: 2016-10-22
• Subjects: Hierarchical structure -- Zeolite -- Catalysis -- Surfactant -- DFT; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2016.07.041
• Languages: English
• ISSNs: 0009-2509

Abstract

Abstract: Hierarchically structured zeolite Y was hydrothermally synthesized using a water glass containing organosilane surfactant as a mesoscale template. The resulting hierarchical zeolite Y was characterized by a complementary combination of X-ray powder diffraction, Fourier transform infrared spectroscopy, N2 adsorption–desorption isotherms, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, 27 Al MAS NMR spectroscopy and density functional theory (DFT) calculation. These results indicated that the hierarchical zeolite Y contained disordered intracrystal mesopores. In addition, quantum chemical calculation results showed that organosilane surfactants could be easily dispersed into the viscous gel used in the synthesis of zeolite Y, inhibiting the phase-separation phenomenon. Hierarchical zeolite Y exhibited remarkably higher resistance to deactivation in the aldol condensation reaction of benzaldehyde with n-butyl alcohol than that of commercial zeolite Y, which is attributed to the highly mesoporous structure that can improve access of reactant molecules to the active sites and minimize the diffusion length of coke precursors out of the zeolite matrix. Such hierarchically porous zeolite Y is very attractive for applications in adsorption and catalysis involving bulky molecules. Highlights: Hierarchical zeolite Y was synthesized using organosilane surfactant template. The synthesized hierarchical zeolite Y possesses intra-crystal mesopores. Molecular properties of surfactant were investigated through the DFT calculation. The resultant hierarchical zeolite Y exhibits high resistance to deactivation.