Temperature-regulated construction of hierarchical titanosilicate zeolites

2020 ◽  
Vol 7 (9) ◽  
pp. 1872-1879
Author(s):  
Yue Song ◽  
Risheng Bai ◽  
Yongcun Zou ◽  
Zhaochi Feng ◽  
Jihong Yu
Keyword(s):  
Zeolite Catalysts ◽  
Organic Template ◽  
Hydrothermal Crystallization ◽  
Tetrabutylammonium Hydroxide

A temperature-regulated method was developed to construct anatase-free hierarchical TS-1 zeolite catalysts by utilizing a two-step hydrothermal crystallization strategy with tetrabutylammonium hydroxide as the sole organic template.

Structural and High Resolution Studies Of B-Zeolite Catalysts Using TEM and Fourier Transform Processing Techniques

1987 ◽  
Vol 111 ◽  
Author(s):  
Miguel Jóse-Yacamán ◽  
J. G. Pérez-Ramírez ◽  
D. R. Acosta ◽  
J. P. Gilson ◽  
G. C. Edwards
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
Zeolite Beta ◽  
Zeolite Catalysts ◽  
Shale Oil ◽  
Organic Template ◽  
Tetraethylammonium Hydroxide ◽  
High Silica ◽  
Selective Adsorbent ◽  
Processing Techniques

Zeolite Beta, synthesized in 1967 (1), is the first example of a large pore, high silica zeolite (SiO2O3 > 20) prepared in the presence of an organic template (Tetraethylammonium Hydroxide). Zeolite NU-2, whose synthesis has been reported in 1982 (2) seems to be related to the zeolite Beta. Although Zeolite Beta has been claimed as useful catalyst in hydrocracking (3), cracking (4), dewaxing (5), hydrotreating (6), shale oil (7) and Fisher-Tropsh products (B) conversions and as a selective adsorbent in the separation of alkylaromatics (9); this zeolite has not been extensively characterized in the open literature.

Effect of different seed sources on the hydrothermal crystallization of MCM-22 zeolite catalysts

CrystEngComm ◽  
2018 ◽  
Vol 20 (25) ◽  
pp. 3467-3475 ◽  
Author(s):  
Mariana V. Rodrigues ◽  
Luiz H. Vieira ◽  
Guilherme P. Campos ◽  
Leandro Martins
Keyword(s):  
Mother Liquor ◽  
Zeolite Catalysts ◽  
Hydrothermal Crystallization ◽  
Considerable Decrease ◽  
Seed Sources ◽  
Crystallite Sizes

Ball-milled MCM-22 and dried mother liquor seeds proved to be effective in the synthesis of the MCM-22P lamellar precursor with a low Si/Al ratio. Crystallization times were reduced from 25 to 2–4 days with a considerable decrease in crystallite sizes.

Advances in ultramicrotomy for physical sciences applications

1993 ◽  
Vol 51 ◽  
pp. 710-711
Author(s):  
G. McMahon ◽  
T. Malis
Keyword(s):  
Particle Surface ◽  
Zeolite Catalysts ◽  
Physical Sciences ◽  
Pull Out ◽  
Large Particles ◽  
Novel Applications ◽  
Metal Wires ◽  
Frequent Problem ◽  
Specific Orientation ◽  
Diamond Knife

As with all techniques which are relatively new and therefore underutilized, diamond knife sectioning in the physical sciences continues to see both developments of the technique and novel applications.Technique Developments Development of specific orientation/embedding procedures for small pieces of awkward shape is exemplified by the work of Bradley et al on large, rather fragile particles of nuclear waste glass. At the same time, the frequent problem of pullout with large particles can be reduced by roughening of the particle surface, and a proven methodology using a commercial coupling agent developed for glasses has been utilized with good results on large zeolite catalysts. The same principle (using acid etches) should work for ceramic fibres or metal wires which may only partially pull out but result in unacceptably thick sections. Researchers from the life sciences continue to develop aspects of embedding media which may be applicable to certain cases in the physical sciences.

Performance of Ag-HZSM-5 Zeolite Catalysts in n-heptane Conversion

2017 ◽  
Vol 68 (1) ◽  
pp. 116-120
Author(s):  
Iuliean Vasile Asaftei ◽  
Neculai Catalin Lungu ◽  
Lucian Mihail Birsa ◽  
Ioan Gabriel Sandu ◽  
Laura Gabriela Sarbu ◽  
...  
Keyword(s):  
Aromatic Hydrocarbons ◽  
Metal Content ◽  
Pulse Method ◽  
Acid Strength ◽  
Strength Distribution ◽  
Zeolite Catalysts ◽  
Benzene Toluene ◽  
Acid Strength Distribution ◽  
Silver Cations ◽  
Heptane Conversion

The conversion of n-heptanes into aromatic hydrocarbons benzene, toluene and xylenes (BTX), by the chromatographic pulse method in the temperature range of 673 - 823K was performed over the HZSM-5 and Ag-HZSM-5 zeolites modified by ion exchange with AgNO3 aqueous solutions. The catalysts, HZSM-5 (SiO2/Al2O3 = 33.9), and Ag-HZSM-5 (Ag1-HZSM-5 wt. % Ag1.02, Ag2-HZSM-5 wt. % Ag 1.62; and Ag3-HZSM-5 wt. % Ag 2.05 having different acid strength distribution exhibit a conversion and a yield of aromatics depending on temperature and metal content. The yield of aromatic hydrocarbons BTX appreciably increased by incorporating silver cations Ag+ into HZSM-5.

Use of Nafion membranes in laboratory organic electrosynthesis

1988 ◽  
Vol 53 (12) ◽  
pp. 3164-3170 ◽  
Author(s):  
Jaromír Hlavatý ◽  
Jiří Volke
Keyword(s):  
Glassy Carbon ◽  
Quaternary Ammonium ◽  
Tetrabutylammonium Bromide ◽  
Nafion Membrane ◽  
Carbon Anode ◽  
Tetrabutylammonium Hydroxide ◽  
Nafion Membranes ◽  
Divided Cell ◽  
A Cell ◽  
Tetrabutylammonium Iodide

Electrolysis of quaternary ammonium bromides and iodides in a divided cell with a Nafion membrane yields quaternary polyhalogenides at a carbon anode in water-ethanolic anolytes. The electrodialysis of tetrabutylammonium iodide in a cell with a Nafion membrane enables generation of tetrabutylammonium hydroxide. In electrolytic reduction of nitrobenzene in presence of 1,3-dibromopropane, N-phenylisooxazolidine results in an approx. 60% yield. This electrosynthesis takes place in dimethylformamide with tetrabutylammonium bromide at a glassy-carbon cathode in a divided cell. In the electroreduction of lobelanine hydrogensulfate in a divided cell in acid water-ethanolic media at a lead cathode prevalently lobelanidine has been obtained.

scholarly journals Selective Production of Aromatics from 2-Octanol on Zinc Ion-Exchanged MFI Zeolite Catalysts

Catalysts ◽  
2015 ◽  
Vol 5 (4) ◽  
pp. 2122-2133 ◽  
Author(s):  
Masakazu Iwamoto ◽  
Ryota Takezawa ◽  
Masao Morimoto
Keyword(s):  
Zinc Ion ◽  
Zeolite Catalysts ◽  
Mfi Zeolite

scholarly journals Synthesis of Renewable Diesel through Hydrodeoxygenation Using Pd/zeolite Catalysts

2014 ◽  
Vol 9 ◽  
pp. 139-150 ◽  
Author(s):  
Bambang Heru Susanto ◽  
Mohammad Nasikin ◽  
Sukirno ◽  
Andri Wiyo
Keyword(s):  
Zeolite Catalysts ◽  
Renewable Diesel

Effect of synthesis and activation methods on the character of CoMo/ultrastable Y-zeolite catalysts

2021 ◽  
Vol 19 (1) ◽  
pp. 745-754
Author(s):  
Khoirina Dwi Nugrahaningtyas ◽  
Eddy Heraldy ◽  
Rachmadani ◽  
Yuniawan Hidayat ◽  
Indriana Kartini
Keyword(s):  
Electron Microscopy ◽  
Reduction Process ◽  
Particle Morphology ◽  
Zeolite Catalysts ◽  
X Ray Diffraction ◽  
Y Zeolite ◽  
X Ray ◽  
Irregular Particle ◽  
Transmission Electron ◽  
Pure Metals

Abstract The properties of three types of CoMo/USY catalysts with different synthesized methods have been studied. The sequential and co-impregnation methods followed by activation using calcination and reduction process have been conducted. The properties of the catalysts were examined using Fourier-transform-infrared (FTIR) spectroscopy, X-ray diffraction (XRD) with refinement, and surface area analyzer (SAA). The FTIR spectrum study revealed the enhanced intensity of its Bronsted acid site, and the XRD diffractogram pattern verified the composition of pure metals, oxides, and alloys in the catalyst. The SAA demonstrated the mesoporous features of the catalyst. Scanning electron microscopy showed an irregular particle morphology. Additional analysis using the transmission electron microscopy indicated that the metal has successfully impregnated without damaging the USY structure.

Progress and future challenges in passive NO adsorption over Pd/zeolite catalysts

2021 ◽  
Author(s):  
Guohua Jing ◽  
Johannes W. Schwank ◽  
Alexander J Hill ◽  
Huawang Zhao ◽  
Lei Ma ◽  
...  
Keyword(s):  
Cold Start ◽  
Zeolite Catalysts ◽  
Catalytic Converters ◽  
No Adsorption ◽  
Emission Standards ◽  
Future Challenges ◽  
Future Emission

Future emission standards are becoming increasingly stringent. Around 50% of targeted tailpipe emissions are emitted during the cold-start period, mainly due to the ineffectiveness of catalytic converters in the after-treatment...

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