Silanization‐Based Zeolite Crystallization: Participation Degree and Pathway

Yan, Yueer; Azhati, Arepati; Guo, Xiao; Zhang, Yahong; Tang, Yi

doi:10.1002/chem.201501034

Cited by 13 publications

(4 citation statements)

References 41 publications

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“…The 29 Si CP NMR spectrum of MWW contained peaks related to Q 3 at −99 ppm, and Q 4 in the range from −105 to −120 ppm (Figure a). The T 3 peak at −63 ppm was observed in the spectra of MWW-8 and MWW-12, since organic groups were connected to the zeolite framework as RSi(OSi zeo ) 3 . The Q 4 environment in the range between −105 and −120 ppm showed that the MWW structure had five inequivalent Si(0Al) sites, due to the Si–O–Si angle in the framework, which varied from 138° to 164°. , For MWW-8, the peak at −100 ppm was more intense than the one located at −104 ppm, while for the MWW and MWW-12 samples, the −104 ppm peak was more intense.…”

Section: Resultsmentioning

confidence: 97%

Organosilane-Assisted Synthesis of Hierarchical MCM-22 Zeolites for Condensation of Glycerol into Bulky Products

Rodrigues

Okolie

Sievers

et al. 2018

Crystal Growth & Design

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Hierarchical micro-mesoporous MCM-22 zeolites were synthesized using hexamethyleneimine and organosilanes as structure directing agents, which enabled the formation of hierarchical zeolites with mesopores created by the voids left by the organosilanes after thermal treatment, without loss of the intrinsic microporosity of the zeolite. The addition of organosilanes to the synthesis medium reduced the incorporation of aluminum atoms into the zeolite framework, making the hierarchical zeolites more hydrophobic than the microporous MCM-22 reference material. Measurements of the contact angles between water droplets and the zeolites pressed into wafers confirmed the distinct hydrophobic character of the samples. The zeolites were used as catalysts for the liquid-phase condensation of glycerol with acetone. Diffusion of the bulky products in the purely microporous zeolites was hindered due to steric constraints. On the other hand, the hierarchical zeolites showed improved catalytic performance in the glycerol condensation reaction, due to greater access to the active acid sites and increased hydrophobicity, which helped in removing water formed in the reaction from the zeolite cavities. The zeolite synthesized with the organosilane bearing 12 carbon atoms in the alkyl chain provided glycerol conversion of 83% in 2 h, while limited conversion of 19% was obtained over the purely microporous sample. In addition to the satisfactory catalytic results observed in the glycerol condensation reaction, the one-pot synthesis procedure employed was simple and allowed the creation of hierarchical zeolites with narrow mesopore size ranges and excellent potential for the conversion of platform molecules derived from biomass sources.

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Section: Resultsmentioning

confidence: 97%

Organosilane-Assisted Synthesis of Hierarchical MCM-22 Zeolites for Condensation of Glycerol into Bulky Products

Rodrigues

Okolie

Sievers

et al. 2018

Crystal Growth & Design

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“…Nanosized hierarchical ITQ-21 zeolites have been prepared using quaternary ammonium hydroxide . Organosilane is also beneficial for perturbing the zeolite nucleation and crystal growth periods . Hierarchical ZSM-5 nanocrystals were synthesized by adding triethoxyphenylsilane .…”

Section: Introductionmentioning

confidence: 99%

“…12 Organosilane is also beneficial for perturbing the zeolite nucleation and crystal growth periods. 13 Hierarchical ZSM-5 nanocrystals were synthesized by adding triethoxyphenylsilane. 14 Uniform cubic nanocrystals of ZSM-5 were synthesized using hexadecyltrimethoxysilane and organic solvent.…”

Section: Introductionmentioning

confidence: 99%

Wheel-like Mordenite Nanoassemblies with Shortened Channel Lengths for Improved Catalytic Performance in Dimethyl Ether Carbonylation

Liu,

Wang,

et al. 2023

ACS Appl. Nano Mater.

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To achieve a better catalytic performance, it is of great interest to synthesize nanosized zeolites with reduced internal diffusion limitations. Herein, c-axis shortened wheel-like mordenite nanoassemblies were synthesized. The crystal growth along the [001] direction was successfully inhibited with K + cations as structure breaking agents. The wheel-like crystal is 1.5−2 μm in diameter and 200−300 nm in thickness. The growth of such a unique structure underwent a nonclassical crystallization process including the generation of amorphous worm-like particles and formation of wheel-like crystallites followed by a−b plane oriented growth of the crystals. The obtained MOR wheel-like assemblies possessed larger surface area and external surface area, displayed better mass transfer properties, and exhibited much better catalytic performance than MOR spheroid-like assemblies and conventional bulk MOR zeolite in dimethyl ether (DME) carbonylation reaction, with two and a half times higher the conversion of DME than the bulk MOR, although these samples had identical Si/Al ratios and acid properties. This work provides a simple route to control the zeolite morphology by alkali metal cations and brings forward an effective strategy to prepare zeolite materials with improved catalytic performance.

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“…They have been used as fillers for poly(vinylidene fluoride) , polycarbonate, poly(methyl methacrylate), and many others . The most popular and common used method of modifying zeolites is silanization . However, during this process, the obtained layer is much less similar to the phenolic resin as the polyaryl layer during modification by diazonium salt.…”

Section: Introductionmentioning

confidence: 99%

Mechanically robust and thermally stable abrasive tools from phenolic resins reinforced with diazonium‐modified zeolites

et al. 2018

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The contact area between the filler and the polymer is a critical region that influences to a great extent the filler–matrix adhesion and therefore the mechanical properties of the composite. Controlling the type of interactions at this interface has a significant effect on the properties of the composite materials. In this context, we prepared composites by covalent reaction of diazonium‐functionalized zeolite with phenol‐formaldehyde resin. Introducing the hydroxymethyl groups onto the surface of the filler via diazonium chemistry allows for covalent bonds between the resin and the modified filler. Such a modification resulted in higher flexural strength of the composites, better ability to dissipate mechanical energy during load and also better damping properties (which are strongly linked to the final product durability) compared with the composites bearing pristine zeolite filler. Moreover, application of modified filler accelerates the crosslinking of novolac resin used as a binder in abrasive tools. One key feature of the work was brought by thermogravimetric analysis–mass spectrometry results which indicate no release of toxic urotropine degradation products for composites containing modified fillers. This work demonstrates conclusively that diazonium‐functionalized zeolite filler particles improve remarkably the thermal and mechanical properties of novolac‐based composites. Such robust composites have high potential in the production of novel abrasive tools. POLYM. COMPOS., 40:3209–3219, 2019. © 2018 Society of Plastics Engineers

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Silanization‐Based Zeolite Crystallization: Participation Degree and Pathway

Cited by 13 publications

References 41 publications

Organosilane-Assisted Synthesis of Hierarchical MCM-22 Zeolites for Condensation of Glycerol into Bulky Products

Organosilane-Assisted Synthesis of Hierarchical MCM-22 Zeolites for Condensation of Glycerol into Bulky Products

Wheel-like Mordenite Nanoassemblies with Shortened Channel Lengths for Improved Catalytic Performance in Dimethyl Ether Carbonylation

Mechanically robust and thermally stable abrasive tools from phenolic resins reinforced with diazonium‐modified zeolites

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