Cooperative structure-directing effect of choline cation and *BEA zeolite in the synthesis of aluminogermanosilicate IWR zeolite

Fu, Wenhua; Yuan, Zhiqing; Jin, Shaoqing; Liu, Wei; Wang, Zhendong; Wang, Chuanming; Wang, Yangdong; Yang, Weimin; He, Min

doi:10.1016/s1872-2067(19)63324-3

Cited by 10 publications

(7 citation statements)

References 66 publications

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“…Both OTMAC and SFE zeolite seed are needed for the synthesis of MTT zeolite, which is similar to the synthesis of IWR zeolite with the presence of both * BEA zeolite seed and choline. 25 Thus, it is appropriate to say that the synthesis was realized successfully through a cooperative structure-directing method.…”

Section: Resultsmentioning

confidence: 99%

“…Lately, the cooperative structure-directing method was reported. 25 Hydrothermally stable aluminogermanosilicate IWR zeolite was synthesized with the simultaneous presences of both * BEA seed and choline, which together direct the crystallization of IWR zeolite. Fang et al synthesized NU-87 ( NES ) zeolite by adding zeolite EU-1 ( EUO ) as the exotic seed in the presence of decamethonium bromide.…”

Section: Introductionmentioning

confidence: 99%

“…Lately, the cooperative structure-directing method was reported . Hydrothermally stable aluminogermanosilicate IWR zeolite was synthesized with the simultaneous presences of both * BEA seed and choline, which together direct the crystallization of IWR zeolite.…”

Section: Introductionmentioning

confidence: 99%

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Syntheses of MTT-Type Zeolites with the Presence of Both Octyltrimethylammonium Chloride and SFE-Type Zeolite Seeds

Liu

et al. 2021

ACS Omega

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Structure-directing agents (SDAs) play important roles in directing the formation of specific zeolite frameworks. Mechanisms and working hypothesis were proposed for understanding how SDAs work during the crystallization of zeolites. The lately reported cooperative structure-directing effect based on the investigation into the synthetic system containing both seed and organic species is one of them and is believed to be effective for synthesizing zeolites which are difficult to access or with novel structures. However, more examples are still needed to support the thesis. Herein, we report for the first time the syntheses of MTT -type zeolites with the simultaneous presences of octyltrimethylammonium chloride (OTMAC) and SFE zeolite seeds in the borosilicate system. SFE borosilicate zeolites serve as exotic seeds for the crystallization of MTT -type zeolites and together with OTMAC play cooperative structure-directing roles. Besides, Al,B- MTT and heteroatom (Zr, V, and Fe)-incorporated MTT -type zeolites were directly synthesized with the introduction of metal sources into the borosilicate system. Physicochemical properties of the obtained MTT zeolites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N 2 physisorption, NH 3 -TPD, 27 Al NMR, 13 C NMR, 11 B NMR, UV–visible spectroscopy, and UV Raman spectroscopy. The herein-reported phenomenon provides an example to better understand the mechanism of zeolite crystallization, and the synthesized zeolites may act as promising catalytic materials in several organic reactions.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Syntheses of MTT-Type Zeolites with the Presence of Both Octyltrimethylammonium Chloride and SFE-Type Zeolite Seeds

Liu

et al. 2021

ACS Omega

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“…As a typical IWR structure, ITQ-24 zeolite discovered by Corma et al, was first synthesized in the presence of germanium species using hexamethonium as an organic template . Because of its unique three-dimensional 12 × 10 × 10-membered ring pore structure (aperture size of 5.8 × 6.8, 4.6 × 5.3, and 4.6 × 5.3 Å), it has attracted much attention recently. , − However, when a large amount of germanium species exist in the IWR framework, its thermal and hydrothermal stabilities are remarkably reduced. In addition, the use of germanium species in the synthesis is costly, which strongly hinders the applications of IWR zeolite in industrial chemical processes. , To solve this problem, alternatively Ge-free synthesis routes were developed for synthesis of IWR zeolite by introduction of boron species instead of germanium.…”

Section: Introductionmentioning

confidence: 99%

Direct Synthesis of Aluminosilicate IWR Zeolite from a Strong Interaction between Zeolite Framework and Organic Template

et al. 2019

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A large amount of zeolite structures are still not synthetically available or not available in the form of aluminosilicate currently. Despite significant progress in the development of predictive concepts for zeolite synthesis, accessing some of these new materials is still challenging. One example is the IWR structure as well. Despite successful synthesis of Ge-based IWR zeolites, direct synthesis of aluminosilicate IWR zeolite is still not successful. In this report we show how a suitable organic structure directing agent (OSDA), through modeling of an OSDA/zeolite cage interaction, could access directly the aluminum-containing IWR structure (denoted as COE-6), which might allow access to new classes of materials and thus open opportunities in valuable chemical applications. The experimental results reveal that the COE-6 zeolites with a SiO2/Al2O3 ratio as low as 30 could be obtained. Very interestingly, the COE-6 zeolite has much higher hydrothermal and thermal stabilities than those of the conventional Ge–Al–IWR zeolite. In methanol-to-propylene (MTP) reaction, the COE-6 zeolite exhibits excellent selectivity for propylene, offering a potential catalyst for MTP reaction in the future.

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“…The presence of these peaks in all catalysts is an indication that there were no significant changes with respect to the structure of the support, even after performing the dealumination procedure and niobium aqueous impregnation. Furthermore, as it was not possible to identify the presence of characteristic niobium oxide signals, it is also possible to infer that there might be a good dispersion of it on the support, or that there was the formation of amorphous species small enough that they could be not be detected by powder XRD [ 23 , 30 ]. We observed a decrease in the crystallinity content of the catalysts from 100% for HB, 87% for DB, 85% for 10%Nb-DB, 77% for 18%Nb-DB, and 85% for 25%Nb-DB, which did not significantly compromise the zeolite structure, as discussed previously.…”

Section: Resultsmentioning

confidence: 99%

Niobium on BEA Dealuminated Zeolite for High Selectivity Dehydration Reactions of Ethanol and Xylose into Diethyl Ether and Furfural

et al. 2020

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In this work, we investigated the role of solid-state dealumination by (NH4)2SiF6 (25% Al removal and 13% Si insertion), the impregnation of niobium (10, 18, and 25 wt. %) on dealuminated *BEA (DB) zeolite and their catalytic properties in ethanol and xylose transformations. Among all the studied catalysts, 18%Nb-DB showed increased mesoporosity and external areas. A leveling effect in the number and strength of the proposed two sites (Brønsted and Lewis) present in the catalyst (n1 = 0.24 mmol g−1, −ΔH1 = 49 kJ mol−1, and n2 = 0.20 mmol g−1, –ΔH2 = 42 kJ mol−1) in the catalyst 18%Nb-DB, might be responsible for its good activity. This catalyst presented the highest selectivity for diethyl ether, DEE (97%) with 61% conversion after 50 ethanol pulses at 230 °C (turnover number, TON DEE = 1.15). These features allowed catalytically fruitful bonding of the ethanol molecules to the neighboring sites on the channels, facilitating bimolecular ether formation through a possible SN2 mechanism. The same catalyst was active and selective for transformation of xylose at 180 °C, showing 64% conversion and 51% selectivity for furfural (TON Furfural = 24.7) using water as a green solvent.

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Cooperative structure-directing effect of choline cation and *BEA zeolite in the synthesis of aluminogermanosilicate IWR zeolite

Cited by 10 publications

References 66 publications

Syntheses of MTT-Type Zeolites with the Presence of Both Octyltrimethylammonium Chloride and SFE-Type Zeolite Seeds

Syntheses of MTT-Type Zeolites with the Presence of Both Octyltrimethylammonium Chloride and SFE-Type Zeolite Seeds

Direct Synthesis of Aluminosilicate IWR Zeolite from a Strong Interaction between Zeolite Framework and Organic Template

Niobium on BEA Dealuminated Zeolite for High Selectivity Dehydration Reactions of Ethanol and Xylose into Diethyl Ether and Furfural

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