Journal ArticleDOI
The Role of Organic and Inorganic Structure-Directing Agents in Selective Al Substitution of Zeolite.
Zhili Wang,Zhili Wang,Weifeng Chu,Zhenchao Zhao,Zhengmao Liu,Zhengmao Liu,Hongyu Chen,Hongyu Chen,Dong Xiao,Ke Gong,Ke Gong,Fan Li,Fan Li,Xiujie Li,Guangjin Hou +14 more
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TLDR
In this paper, the roles of different structure-directing agents (SDAs) in selective substitution of MCM-49 zeolite are investigated comprehensively by multinuclear solid-state NMR.Abstract:
Organic and inorganic structure-directing agents (SDAs) impact Al distributions in zeolite, but the insights into how SDAs manipulate Al distribution have not been elucidated yet. Herein, the roles of different SDAs such as cyclohexylamine (CHA), hexamethylenimine (HMI), and Na+ in selective Al substitution of MCM-49 zeolite are investigated comprehensively by multinuclear solid-state NMR. The results demonstrate that MCM-49 synthesized with HMI shows relatively more T6 and T7 Al, while more T2 Al is observed using CHA. The formation of T2 Al in both MCM-49(HMI) and MCM-49(CHA) is derived from Na+, while protonated HMIs show bias in incorporation of T6 and T7 Al. Most HMIs are occluded in protonated status, and about half of CHAs are occluded in nonprotonated status. The close spatial proximity between nonprotonated CHAs and Na+ synergistically promotes the formation of zeolite structure, leading to more Na+ ions occluded in the zeolite channel with preferential T2 Al substitution.read more
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Targeted synthesis of zeolites from calculated interaction between zeolite structure and organic template
TL;DR: In this paper , a review of recent progress in the targeted synthesis of zeolites from interaction between a zeolite structure and an organic template is briefly outlined, including the design of new templates for zeolate synthesis, preparation of zeolate with new composition, development of novel routes for zeolinite synthesis, synthesis of intergrowth zeolitic intergrowth, generation of novel zeolate structures, and control of the zeolate morphology and modulation of aluminum distribution.
Journal ArticleDOI
OUP accepted manuscript
TL;DR: In this article , a review of recent progress in the targeted synthesis of zeolites from interaction between a zeolite structure and an organic template is briefly outlined, including the design of new templates for zerosite synthesis, preparation of zerosites with new composition, development of novel routes for zeoliset synthesis, synthesis of intergrowth zerosets, generation of novel zeroset structures, control of zeolset morphology, and modulation of aluminum distribution in zeolsite.
Journal ArticleDOI
Regulation of the Si/Al ratios and Al distributions of zeolites and their impact on properties
TL;DR: In this paper , the authors discussed the basic principles and the state-of-the-art methodologies for regulating the Si/Al ratios and Al distributions of zeolites, including seed-assisted recipe modification, interzeolite transformation, fluoride media, and usage of organic structure-directing agents.
Journal ArticleDOI
Driving the Active Site Incorporation in Zeolitic Materials via the Organic Structure‐Directing Agent Through Development of H‐Bonds with Hydroxyl Groups
Beatriz Bernardo-Maestro,Jian Li,Joaquín Pérez-Pariente,Fernando López-Arbeloa,Luis Gómez-Hortigüela +4 more
TL;DR: In this paper , the authors demonstrate that H-bond forming groups can be used to drive the spatial incorporation of low-valent dopants within zeolitic frameworks, a highly desired aim in order to control their catalytic activity and selectivity.
Journal ArticleDOI
Clarification of acid site location in MSE-type zeolites by spectroscopic approaches combined with catalytic activity: comparison between UZM-35 and MCM-68.
Hiroto Toyoda,Ryota Osuga,Yong Wang,Sungsik Park,Koji Yazawa,Hermann Gies,Christopher J. Gilbert,Bilge Yilmaz,C. P. Kelkar,Toshiyuki Yokoi +9 more
TL;DR: In this article , the location of Brønsted acid sites derived from the framework Al atoms and acidic properties were investigated based on 27Al MQMAS NMR and in situ IR techniques combined with the evaluation of the catalytic activity.
References
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Journal ArticleDOI
Zeolite and molecular sieve synthesis
Mark E. Davis,Raul F. Lobo +1 more
TL;DR: In this paper, the ability to plan zeolite and molecular sieve syntheses is discussed and a strategy for synthesizing chiral zeolites is used to demonstrate the current limitations in "designing" new molecular sieves.
Journal ArticleDOI
The hydrothermal synthesis of zeolites: precursors, intermediates and reaction mechanism
Colin S. Cundy,Paul A. Cox +1 more
TL;DR: An account of the mechanistic aspects of hydrothermal zeolite synthesis can be found in this paper, where a review of the most probable mechanistic pathways in Zeolite formation is given.
Journal ArticleDOI
MCM-22: A Molecular Sieve with Two Independent Multidimensional Channel Systems
TL;DR: The molecular sieve MCM-22 contains structural features previously unobserved in this class of materials, including an unusual -T-O-T- chain that passes through the center of a modified dodecasil-1H cage.
Journal ArticleDOI
Synthesis of new zeolite structures
TL;DR: The advances in the synthesis of new zeolite structures in the last decade are presented, which are achieved by utilization of the synthetic strategies based on pre-designed structure-directing agents, heteroatom substitution, and topotactic transformations.