scholarly journals In Situ Synthesis of Sn-Beta Zeolite Nanocrystals for Glucose to Hydroxymethylfurfural (HMF)

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1249
Author(s):  
Kachaporn Saenluang ◽  
Anawat Thivasasith ◽  
Pannida Dugkhuntod ◽  
Peerapol Pornsetmetakul ◽  
Saros Salakhum ◽  
...  
Keyword(s):  
Biomass Conversion ◽  
Hydrothermal Process ◽  
Acid Sites ◽  
Beta Zeolite ◽  
Structure Directing Agent ◽  
Zeolite Type ◽  
Acid Function ◽  
Diquaternary Ammonium ◽  
Catalytic Performances

The Sn substituted Beta nanocrystals have been successfully synthesized by in-situ hydrothermal process with the aid of cyclic diquaternary ammonium (CDM) as the structure-directing agent (SDA). This catalyst exhibits a bifunctional catalytic capability for the conversion of glucose to hydroxymethylfurfural (HMF). The incorporated Sn acting as Lewis acid sites can catalyze the isomerization of glucose to fructose. Subsequently, the Brønsted acid function can convert fructose to HMF via dehydration. The effects of Sn amount, zeolite type, reaction time, reaction temperature, and solvent on the catalytic performances of glucose to HMF, were also investigated in the detail. Interestingly, the conversion of glucose and the HMF yield over 0.4 wt% Sn-Beta zeolite nanocrystals using dioxane/water as a solvent at 120 °C for 24 h are 98.4% and 42.0%, respectively. This example illustrates the benefit of the in-situ synthesized Sn-Beta zeolite nanocrystals in the potential application in the field of biomass conversion.

scholarly journals Synthesis of SAPO-34 Nanoplates with High Si/Al Ratio and Improved Acid Site Density

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3198
Author(s):  
Syed Fakhar Alam ◽  
Min-Zy Kim ◽  
Aafaq ur Rehman ◽  
Devipriyanka Arepalli ◽  
Pankaj Sharma ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Molecular Sieves ◽  
Active Sites ◽  
High Performance ◽  
Hydrothermal Process ◽  
Acid Sites ◽  
High Density ◽  
Structure Directing Agent ◽  
Transfer Resistance ◽  
Low Mass

Two-dimensional SAPO-34 molecular sieves were synthesized by microwave hydrothermal process. The concentrations of structure directing agent (SDA), phosphoric acid, and silicon in the gel solution were varied and their effect on phase, shape, and composition of synthesized particles was studied. The synthesized particles were characterized by various techniques using SEM, XRD, BET, EDX, and NH3-TPD. Various morphologies of particles including isotropic, hyper rectangle, and nanoplates were obtained. It was found that the Si/Al ratio of the SAPO-34 particles was in a direct relationship with the density of acid sites. Moreover, the gel composition and preparation affected the chemistry of the synthesized particles. The slow addition of phosphoric acid improved the homogeneity of synthesis gel and resulted in SAPO-34 nanoplates with high density of acid sites, 3.482 mmol/g. The SAPO-34 nanoplates are expected to serve as a high performance catalyst due to the low mass transfer resistance and the high density of active sites.

scholarly journals A Facile Strategy to Prepare Shaped ZSM-5 Catalyst with Enhanced para-Xylene Selectivity and Stability for Toluene Methylation

2017 ◽  
Author(s):  
Yiren Wang ◽  
Yang Chang ◽  
Min Liu ◽  
Anfeng Zhang ◽  
Chunshan Song ◽  
...  
Keyword(s):  
Physical Adsorption ◽  
Catalytic Performance ◽  
Acid Sites ◽  
The Novel ◽  
In Situ Xrd ◽  
Para Xylene ◽  
Toluene Methylation ◽  
Temperature Programmed ◽  
Catalytic Performances

This work describes the catalytic performances of attapulgite/ZSM-5 extrudate in comparison to conventional alumina-bound ZSM-5 extrudate in toluene methylation. The novel attapulgite/ZSM-5 extrudate is prepared by using natural clay attapulgite as binder which introduces mobile alkaline species and macropores to the extrudate. In contrast to alumina-bound extrudate, this novel extrudate shows significantly higher para-selectivity and stability. By using characterization techniques, including in-situ XRD, SEM, NH3 temperature programmed desorption (TPD), thermogravimetric analysis and n-hexane/cyclohexane physical adsorption, the catalytic performance improvement of attapulgite/ZSM-5 extrudate is correlated with the neutralization of Brønsted acid sites by mobile alkaline species during calcination and reaction process. Moreover, a higher para-selectivity was obtained over attapulgite-bound modified ZSM-5 extrudate. The strategy of extruding ZSM-5 catalysts with attapulgite as binder is facile and universal. Such method paves a new way for preparation of shaped toluene methylation catalyst with enhanced para-selectivity and stability.

scholarly journals Offretite Zeolite Single Crystals Synthesized by Amphiphile-Templating Approach

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2238
Author(s):  
Eng-Poh Ng ◽  
Nur Hidayahni Ahmad ◽  
Fitri Khoerunnisa ◽  
Svetlana Mintova ◽  
Tau Chuan Ling ◽  
...  
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Cost Effective ◽  
Acid Sites ◽  
Biofuel Production ◽  
Structure Directing Agent ◽  
High Crystallinity ◽  
Organic Templates ◽  
Synthesis Approach ◽  
Conventional Counterpart ◽  
Dual Functions

Offretite zeolite synthesis in the presence of cetyltrimethylammonium bromide (CTABr) is reported. The offretite crystals were synthesized with a high crystallinity and hexagonal prismatic shape after only 72 h of hydrothermal treatment at 180 °C. The CTABr has dual-functions during the crystallization of offretite, viz. as structure-directing agent and as mesoporogen. The resulting offretite crystals, with a Si/Al ratio of 4.1, possess more acid sites than the conventional offretite due to their high crystallinity and hierarchical structure. The synthesized offretite is also more reactive than its conventional counterpart in the acylation of 2-methylfuran for biofuel production under non-microwave instant heating condition, giving 83.5% conversion with 100% selectivity to the desired product 2-acetyl-5-methylfuran. Hence, this amphiphile synthesis approach offers another cost-effective and alternative route for crystallizing zeolite materials that require expensive organic templates.

A flexible lead-free piezoelectric nanogenerator based on vertically aligned BaTiO3 nanotube arrays on a Ti-mesh substrate

RSC Advances ◽  
2016 ◽  
Vol 6 (84) ◽  
pp. 81426-81435 ◽  
Author(s):  
Ermias Libnedengel Tsege ◽  
Gyu Han Kim ◽  
Venkateswarlu Annapureddy ◽  
Beomkeun Kim ◽  
Hyung-Kook Kim ◽  
...  
Keyword(s):  
Low Temperature ◽  
Titanium Oxide ◽  
Hydrothermal Process ◽  
Lead Free ◽  
Nanotube Arrays ◽  
Titanium Oxide Nanotubes ◽  
Vertically Aligned ◽  
Ti Mesh

A novel, flexible lead-free piezoelectric nanogenerator was developed using a uniform BaTiO3 film; synthesized by in situ conversion of titanium oxide nanotubes in a low temperature hydrothermal process.

Enhanced lithium storage in a VO2(B)-multiwall carbon nanotube microsheet composite prepared via an in situ hydrothermal process

2010 ◽  
Vol 56 (2) ◽  
pp. 693-699 ◽  
Author(s):  
M.M. Rahman ◽  
Jia-Zhao Wang ◽  
Nurul Hayati Idris ◽  
Zhixin Chen ◽  
Huakun Liu
Keyword(s):  
Carbon Nanotube ◽  
Hydrothermal Process ◽  
Multiwall Carbon Nanotube ◽  
Lithium Storage ◽  
Multiwall Carbon

Zn modification of Beta zeolite: Effect on acid sites and propylene oxide rearrangement

2020 ◽  
Vol 539 ◽  
pp. 110983
Author(s):  
Baoqiang Zhang ◽  
Xiangshuai Zhu ◽  
Jiang Gao ◽  
Yingluo Zhu ◽  
Weihua Ma
Keyword(s):  
Propylene Oxide ◽  
Acid Sites ◽  
Beta Zeolite

In-situ FTIR to unravel the bifunctional nature of aromatics hydrogenation synergy on zeolite / metal catalysts

2022 ◽  
Author(s):  
Nuno Batalha ◽  
Jean-Dominique Comparot ◽  
Anthony Le Valant ◽  
Ludovic Pinard
Keyword(s):  
Catalytic Performance ◽  
Acid Sites ◽  
Metal Catalysts ◽  
In Situ Ftir

Acid sites, in particular Brønsted sites, are often reported to enhance the catalytic performance of metal catalysts, like platinum, in hydrogenation. The significant boost in catalytic performance suggests a bifunctional...

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