Epoxidation of 1-octene under harsh tail-end conditions in a flow reactor II: impact of delaminated-zeolite catalyst surface area and structural integrity on catalytic performance

2017 ◽  
Vol 2 (6) ◽  
pp. 852-861 ◽  
Author(s):  
Martina Aigner ◽  
Nicolás Andrés Grosso-Giordano ◽  
Christian Schöttle ◽  
Alexander Okrut ◽  
Stacey Zones ◽  
...  
Keyword(s):  
Surface Area ◽  
Structural Integrity ◽  
Zeolite Catalyst ◽  
Flow Reactor ◽  
Catalyst Surface ◽  
Catalytic Performance ◽  
Zeolite Catalysts ◽  
Olefin Epoxidation ◽  
End Conditions

The effect of delamination approach of zeolite catalysts was investigated for olefin epoxidation in a flow reactor.

scholarly journals Utilization of Natural Zeolite Catalyst Impregnated Sn Metal in Glucose Isomerization With Temperature Variations

ALCHEMY ◽  
2015 ◽  
Vol 4 (1) ◽  
Author(s):  
Dwi Putri W. Pamungkas ◽  
Suci Amalia ◽  
Susi Nurul Khalifah
Keyword(s):  
Surface Area ◽  
Natural Zeolite ◽  
Zeolite Catalyst ◽  
Hydrothermal Process ◽  
Xrd Analysis ◽  
Zeolite Catalysts ◽  
Edax Analysis ◽  
Modification Process ◽  
Glucose Isomerization ◽  
Ammonia Method

<p>Studied the characteristics of natural zeolite catalysts activated and modifications and catalytic activity in the isomerization of glucose. Natural zeolite was activated by NH<sub>4</sub>NO<sub>3</sub> 2 M obtained catalyst HZA. While modification using 0,24 M Sn metal impregnated on HZA obtained catalyst Sn-HZA. At this stage, hydrothermal process carried out at temperature of 90 °C for 12 hours followed by calcination at temperature of 500 °C for 4 hours. The characterization includes the XRD analysis, SEM-EDAX analysis, acidity by ammonia method, and surface area by adsorption of methylene blue method. Glucose conversion was obtained through analysis of polarimeter at hour-0, 1, 2, 3, and 4 with temperature variation of 110, 120, and 130 °C. Solution which had the highest conversion resulted by polarimeter was analyzed by HPLC. XRD analysis showed that there were no changes in the structure of zeolite after activation and modification process. SEM-EDAX analysis showed that morphology of the zeolite surface is not damaged and Sn metal was successfully impregnated 6,94 %. The activity of HZA and Sn-HZA was 1,4850 mmol/g and 2,3145 mmol/g. while the surface area of HZA and Sn-HZA was 11,4077 m<sup>2</sup>/g and 11,4738 m<sup>2</sup>/g. Using the Sn-HZA catalyst with the reaction temperature of 120 °C provides the highest conversion of glucose and fructose selectivity. It were 14,0733 % w/v and 0,646 % w/v.<em>  </em></p><p class="BodyAbstract"> </p><strong><em>Keywords</em>:</strong> <em>Catalyst, glucose, isomerization, natural zeolite, Sn metal.</em>

scholarly journals Influence of the Reduction Temperature and the Nature of the Support on the Performance of Zirconia and Alumina-Supported Pt Catalysts for n-Dodecane Hydroisomerization

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 88
Author(s):  
Diana García-Pérez ◽  
Maria Consuelo Alvarez-Galvan ◽  
Jose M. Campos-Martin ◽  
Jose L. G. Fierro
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Catalytic Properties ◽  
Catalytic Performance ◽  
Major Influence ◽  
Pt Catalysts ◽  
Reduction Temperature ◽  
Metal Dispersion ◽  
Tungsten Oxides ◽  
Supported Pt Catalysts

Catalysts based on zirconia- and alumina-supported tungsten oxides (15 wt % W) with a small loading of platinum (0.3 wt % Pt) were selected to study the influence of the reduction temperature and the nature of the support on the hydroisomerization of n-dodecane. The reduction temperature has a major influence on metal dispersion, which impacts the catalytic activity. In addition, alumina and zirconia supports show different catalytic properties (mainly acid site strength and surface area), which play an important role in the conversion. The NH3-TPD profiles indicate that the acidity in alumina-based catalysts is clearly higher than that in their zirconia counterparts; this acidity can be attributed to a stronger interaction of the WOx species with alumina. The PtW/Al catalyst was found to exhibit the best catalytic performance for the hydroisomerization of n-dodecane based on its higher acidity, which was ascribed to its larger surface area relative to that of its zirconia counterparts. The selectivity for different hydrocarbons (C7–10, C11 and i-C12) was very similar for all the catalysts studied, with branched C12 hydrocarbons being the main products obtained (~80%). The temperature of 350 °C was clearly the best reduction temperature for all the catalysts studied in a trickled-bed-mode reactor.

scholarly journals A diffusion anisotropy descriptor links morphology effects of H-ZSM-5 zeolites to their catalytic cracking performance

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Xiaoliang Liu ◽  
Jing Shi ◽  
Guang Yang ◽  
Jian Zhou ◽  
Chuanming Wang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Catalytic Cracking ◽  
Catalytic Performance ◽  
Zeolite Catalysts ◽  
Time Resolved ◽  
Cracking Performance ◽  
Morphology Effect ◽  
Ft Ir ◽  
The Difference ◽  
Dynamics Simulations

AbstractZeolite morphology is crucial in determining their catalytic activity, selectivity and stability, but quantitative descriptors of such a morphology effect are challenging to define. Here we introduce a descriptor that accounts for the morphology effect in the catalytic performances of H-ZSM-5 zeolite for C4 olefin catalytic cracking. A series of H-ZSM-5 zeolites with similar sheet-like morphology but different c-axis lengths were synthesized. We found that the catalytic activity and stability is improved in samples with longer c-axis. Combining time-resolved in-situ FT-IR spectroscopy with molecular dynamics simulations, we show that the difference in catalytic performance can be attributed to the anisotropy of the intracrystalline diffusive propensity of the olefins in different channels. Our descriptor offers mechanistic insight for the design of highly effective zeolite catalysts for olefin cracking.

scholarly journals The Effect of Mg and Zn Dopants on Pt/Al2O3 for the Dehydrogenation of Perhydrodibenzyltoluene

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 490
Author(s):  
Rudaviro Garidzirai ◽  
Phillimon Modisha ◽  
Innocent Shuro ◽  
Jacobus Visagie ◽  
Pieter van Helden ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Inductively Coupled Plasma ◽  
Flow Reactor ◽  
Plug Flow ◽  
Optical Emission ◽  
Catalytic Performance ◽  
Emission Spectrometry ◽  
Hydrogen Yield ◽  
X Ray ◽  
Temperature Programmed

The effects of Mg and Zn dopants on the catalytic performance of Pt/Al2O3 catalyst were investigated for dehydrogenation of perhydrodibenzyltoluene (H18-DBT) as a liquid organic hydrogen carrier. Al2O3 supports were modified with Mg and Zn to produce Mg-Al2O3 and Zn-Al2O3 with a target loading of 3.8 wt.% for dopants. The modified supports were impregnated with chloroplatinic acid solution to produce the catalysts Pt/Al2O3, Pt/Mg-Al2O3 and Pt/Zn-Al2O3 of 0.5 wt.% Pt loading. Thereafter, the catalysts were characterised using inductively coupled plasma- optical emission spectrometry, scanning electron microscopy-energy dispersive X-ray spectroscopy, hydrogen temperature-programmed reduction, carbon-monoxide pulse chemisorption, ammonia temperature-programmed desorption, X-ray diffraction and transmission electron microscopy. The dehydrogenation experiments were performed using a horizontal plug flow reactor system and the catalyst time-on-stream was 22 h. Pt/Mg-Al2O3 showed the highest average hydrogen flowrate of 29 nL/h, while an average of 27 nL/h was obtained for both Pt/Al2O3 and Pt/Zn-Al2O3. This has resulted in a hydrogen yield of 80% for Pt/Mg-Al2O3, 71% for Pt/Zn-Al2O3 and 73% for Pt/Al2O3. In addition, the conversion of H18-DBT ranges from 99% to 92%, Pt 97–90% and 96–90% for Pt/Mg-Al2O3, Pt/Zn-Al2O3 and Pt/Al2O3, respectively. Following the latter catalyst order, the selectivity to dibenzyltoluene (H0-DBT) ranges from 78% to 57%, 75–51% and 71–45%. Therefore, Pt/Mg-Al2O3 showed improved catalytic performance towards dehydrogenation of H18-DBT.

Valence variation of phase-pure M1 MoVNbTe oxide by plasma treatment for improved catalytic performance in oxidative dehydrogenation of ethane

RSC Advances ◽  
2015 ◽  
Vol 5 (111) ◽  
pp. 91295-91301 ◽  
Author(s):  
Xin Chen ◽  
Qianli Yang ◽  
Bozhao Chu ◽  
Hang An ◽  
Yi Cheng
Keyword(s):  
Surface Modification ◽  
Metal Oxide ◽  
Plasma Treatment ◽  
Oxidative Dehydrogenation ◽  
Oxidation State ◽  
Active Sites ◽  
Oxygen Plasma ◽  
Catalyst Surface ◽  
Catalytic Performance ◽  
Phase Pure

This work presents a new method of catalyst surface modification by using oxygen plasma to change the oxidation state of active sites in metal oxide catalysts.

scholarly journals High-efficiency catalytic performance over mesoporous Ni/beta zeolite for the synthesis of quinoline from glycerol and aniline

RSC Advances ◽  
2017 ◽  
Vol 7 (16) ◽  
pp. 9551-9561 ◽  
Author(s):  
An Li ◽  
Chen Huang ◽  
Cai-Wu Luo ◽  
Wen-Jun Yi ◽  
Zi-Sheng Chao
Keyword(s):  
Catalytic Activity ◽  
Vapor Phase ◽  
High Efficiency ◽  
Zeolite Catalyst ◽  
Catalytic Performance ◽  
Beta Zeolite ◽  
Phase Process

Quinoline was synthesized via the typical Skraup approach with a vapor-phase process. The mesoporous Ni/beta zeolite catalyst exhibited high-efficiency catalytic activity and an enhanced ability of anti-deactivation.

A mesoporous “shell-in-shell” structured nanocatalyst with large surface area, enhanced synergy, and improved catalytic performance for Suzuki–Miyaura coupling reaction

2014 ◽  
Vol 50 (82) ◽  
pp. 12356-12359 ◽  
Author(s):  
Baocang Liu ◽  
Yuefang Niu ◽  
Yan Li ◽  
Fan Yang ◽  
Jiamin Guo ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Coupling Reaction ◽  
Catalytic Performance ◽  
Large Surface Area ◽  
Mesoporous Shell

A novel mesoporous “shell-in-shell” structured nanoreactor (@Pd/meso-TiO2/Pd@meso-SiO2) shows superior catalytic activity, stability, and selectivity for Suzuki–Miyaura coupling reaction.

scholarly journals Disorders of the erythrocyte membrane

2015 ◽  
Vol 9 (4) ◽  
pp. 323
Author(s):  
Sophia Delicou ◽  
Aikaterini Xydaki ◽  
Chryssanthi Kontaxi ◽  
Konstantinos Maragkos
Keyword(s):  
Surface Area ◽  
Erythrocyte Membrane ◽  
Structural Integrity ◽  
Mechanical Stability ◽  
Hereditary Spherocytosis ◽  
Membrane Surface ◽  
Membrane Skeleton ◽  
Inherited Disorders ◽  
Hereditary Elliptocytosis ◽  
Area Loss

Hemolytic anemia due to abnormalities of the erythrocyte membrane comprises an important group of inherited disorders. These include hereditary spherocytosis, hereditary elliptocytosis, hereditary pyropoikilocytosis, and the hereditary stomatocytosis syndromes. The erythrocyte membrane skeleton composed of spectrin, actin, and several other proteins is essential for the maintenance of the erythrocyte shape, reversible deformability, and membrane structural integrity in addition to controlling the lateral mobility of integral membrane proteins. These disorders are characterized by clinical and laboratory heterogeneity and, as evidenced by recent molecular studies, by genetic heterogeneity. Defects in various proteins involved in linking the lipid bilayer to membrane skeleton result in loss in membrane cohesion leading to surface area loss and hereditary spherocytosis while defects in proteins involved in lateral interactions of the spectrin-based skeleton lead to decreased mechanical stability, membrane fragmentation and hereditary elliptocytosis. The disease severity is primarily dependent on the extent of membrane surface area loss. Treatment with splenectomy is curative in most patients.

The Effects of Preparation Methods on Iron Structures of Iron-Supported HZSM-5 and their Catalytic Performance for Methanol Dehydration

2016 ◽  
Vol 723 ◽  
pp. 633-639
Author(s):  
Waenkaew Pantupho ◽  
Arthit Neramittagapong ◽  
Nuttawut Osakoo ◽  
Jatuporn Wittayakun ◽  
Sirinuch Loiha
Keyword(s):  
Flow Reactor ◽  
Fixed Bed ◽  
Catalytic Performance ◽  
Active Species ◽  
Iron Complex ◽  
Methanol Dehydration ◽  
Low Carbon ◽  
Zeolite Framework ◽  
Preparation Methods ◽  
Binuclear Iron

Iron-supported HZSM-5 catalysts were prepared by hydrothermal (Fe-HZSM-5_HYD) and impregnation methods (Fe/HZSM-5_IMP). The active species of binuclear-iron complex and iron-substituted zeolite framework, confirmed by EXAFS analysis, were observed on Fe/HZSM-5_IMP and Fe-HZSM-5_HYD, respectively. The catalysts were used for production of dimethyl ether (DME) by methanol dehydration at 200-350 °C using fixed bed flow reactor. Fe/HZSM-5_IMP showed higher catalytic conversion than Fe-HZSM-5_HYD. However, the Fe/HZSM-5_IMP catalyst was less selective to DME product and strongly deactivated for 24h. The deactivation might due to transformation of binuclear-iron to the a-iron site which was strong acidic strengh. The iron-substituted zeolite framework of Fe-HZSM-5_HYD showed high stability toward methanol dehydration. Moreover, the catalyst showed advantages of good selective to DME and low carbon deposition on surface. These results suggested that the iron-substituted zeolite framework structure could improve catalytic performance for mrthanol dehydration.

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