scholarly journals Kinetics of Fischer–Tropsch Synthesis in a 3-D Printed Stainless Steel Microreactor Using Different Mesoporous Silica Supported Co-Ru Catalysts

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 872 ◽  
Author(s):  
Mohammad ◽  
Bepari ◽  
Aravamudhan ◽  
Kuila
Keyword(s):  
Stainless Steel ◽  
Mesoporous Silica ◽  
Photoelectron Spectroscopy ◽  
Space Velocity ◽  
Fischer Tropsch ◽  
One Pot ◽  
Ru Catalysts ◽  
Weight Hourly Space Velocity ◽  
Ft Synthesis ◽  
Mcm 41

Fischer–Tropsch (FT) synthesis was carried out in a 3D printed stainless steel (SS) microchannel microreactor using bimetallic Co-Ru catalysts on three different mesoporous silica supports. CoRu-MCM-41, CoRu-SBA-15, and CoRu-KIT-6 were synthesized using a one-pot hydrothermal method and characterized by Brunner–Emmett–Teller (BET), temperature programmed reduction (TPR), SEM-EDX, TEM, and X-ray photoelectron spectroscopy (XPS) techniques. The mesoporous catalysts show the long-range ordered structure as supported by BET and low-angle XRD studies. The TPR profiles of metal oxides with H2 varied significantly depending on the support. These catalysts were coated inside the microchannels using polyvinyl alcohol and kinetic performance was evaluated at three different temperatures, in the low-temperature FT regime (210–270 °C), at different Weight Hourly Space Velocity (WHSV) in the range of 3.15–25.2 kgcat.h/kmol using a syngas ratio of H2/CO = 2. The mesoporous supports have a significant effect on the FT kinetics and stability of the catalyst. The kinetic models (FT-3, FT-6), based on the Langmuir–Hinshelwood mechanism, were found to be statistically and physically relevant for FT synthesis using CoRu-MCM-41 and CoRu-KIT-6. The kinetic model equation (FT-2), derived using Eley–Rideal mechanism, is found to be relevant for CoRu-SBA-15 in the SS microchannel microreactor. CoRu-KIT-6 was found to be 2.5 times more active than Co-Ru-MCM-41 and slightly more active than CoRu-SBA-15, based on activation energy calculations. CoRu-KIT-6 was ~3 and ~1.5 times more stable than CoRu-SBA-15 and CoRu-MCM-41, respectively, based on CO conversion in the deactivation studies.

scholarly journals Facile Strategy for the Synthesis of Gold@Silica Hybrid Nanoparticles with Controlled Porosity and Janus Morphology

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 348 ◽  
Author(s):  
Marina Santana Vega ◽  
Andrés Guerrero Martínez ◽  
Fabio Cucinotta
Keyword(s):  
Mesoporous Silica ◽  
Sodium Silicate ◽  
Chemical Reactivity ◽  
Type Systems ◽  
Plasmonic Nanoparticles ◽  
Hybrid Nanoparticles ◽  
Binary Solvent ◽  
Solvent Mixtures ◽  
One Pot ◽  
Mcm 41

Hybrid materials prepared by encapsulation of plasmonic nanoparticles in porous silica systems are of increasing interest due to their high chemical stability and applications in optics, catalysis and biological sensing. Particularly promising is the possibility of obtaining gold@silica nanoparticles (Au@SiO2 NPs) with Janus morphology, as the induced anisotropy can be further exploited to achieve selectivity and directionality in physical interactions and chemical reactivity. However, current methods to realise such systems rely on the use of complex procedures based on binary solvent mixtures and varying concentrations of precursors and reaction conditions, with reproducibility limited to specific Au@SiO2 NP types. Here, we report a simple one-pot protocol leading to controlled crystallinity, pore order, monodispersity, and position of gold nanoparticles (AuNPs) within mesoporous silica by the simple addition of a small amount of sodium silicate. Using a fully water-based strategy and constant content of synthetic precursors, cetyl trimethylammonium bromide (CTAB) and tetraethyl orthosilicate (TEOS), we prepared a series of four silica systems: (A) without added silicate, (B) with added silicate, (C) with AuNPs and without added silicate, and (D) with AuNPs and with added silicate. The obtained samples were characterised by transmission electron microscopy (TEM), small angle X-ray scattering (SAXS), and UV-visible spectroscopy, and kinetic studies were carried out by monitoring the growth of the silica samples at different stages of the reaction: 1, 10, 15, 30 and 120 min. The analysis shows that the addition of sodium silicate in system B induces slower MCM-41 nanoparticle (MCM-41 NP) growth, with consequent higher crystallinity and better-defined hexagonal columnar porosity than those in system A. When the synthesis was carried out in the presence of CTAB-capped AuNPs, two different outcomes were obtained: without added silicate, isotropic mesoporous silica with AuNPs located at the centre and radial pore order (C), whereas the addition of silicate produced Janus-type Au@SiO2 NPs (D) in the form of MCM-41 and AuNPs positioned at the silica–water interface. Our method was nicely reproducible with gold nanospheres of different sizes (10, 30, and 68 nm diameter) and gold nanorods (55 × 19 nm), proving to be the simplest and most versatile method to date for the realisation of Janus-type systems based on MCM-41-coated plasmonic nanoparticles.

scholarly journals Fischer-Tropsch studies in a 3D-printed stainless steel microchannel microreactor coated with cobalt-based bimetallic-MCM-41 catalysts

2020 ◽  
Vol 358 ◽  
pp. 303-315 ◽  
Author(s):  
Nafeezuddin Mohammad ◽  
Richard Y. Abrokwah ◽  
Robert G. Stevens-Boyd ◽  
Shyam Aravamudhan ◽  
Debasish Kuila
Keyword(s):  
Stainless Steel ◽  
Fischer Tropsch ◽  
3D Printed ◽  
Mcm 41

scholarly journals Effect of cerium content on textural and hydrodesulfurization performance for dibenzothiophene over a bulk Ni2P catalyst

2019 ◽  
Vol 44 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Yunwu Yu ◽  
Lianjie Liang ◽  
Changwei Xu ◽  
Yubo Dai ◽  
Wenhao Pan ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Photoelectron Spectroscopy ◽  
Space Velocity ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
X Ray ◽  
Weight Hourly Space Velocity ◽  
Cerium Content ◽  
Adsorption Desorption ◽  
Hydrodesulfurization Activity

A series of ceria promoted Ni2P catalysts were prepared and evaluated in dibenzothiophene hydrodesulfurization steam. These catalysts were characterized by X-ray diffraction, N2 adsorption–desorption, CO chemisorptions, and X-ray photoelectron spectroscopy. The results showed that the addition of ceria into the bulk Ni2P catalyst was conducive to the formation of the Ni2P phase and contributed to a higher surface area, leading to a better dispersion and smaller crystallite size of Ni2P particles. The CexNi2P catalysts showed higher dibenzothiophene hydrodesulfurization activity than Ni2P catalyst and the Ce0.09Ni2P catalyst showed the highest dibenzothiophene hydrodesulfurization activity. The Ce0.09Ni2P catalyst showed a dibenzothiophene hydrodesulfurization conversion of 94.5% at the reaction conditions of 320°C, 4.0 MPa, a H2/oil ratio of 500 (V/V), and a weight hourly space velocity of 8.0 h−1. The dibenzothiophene was mainly transformed through desulfurization pathway.

scholarly journals One-Pot Room-Temperature Synthesis of Mg Containing MCM-41 Mesoporous Silica for Aldol Reactions

2018 ◽  
Vol 34 (12) ◽  
pp. 2521-2528 ◽  
Author(s):  
Shin-Ichiro Fujita ◽  
Shinji Segawa ◽  
Kazuki Kawashima ◽  
Xuejing Nie ◽  
Tomoki Erata ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Room Temperature ◽  
Aldol Reactions ◽  
Temperature Synthesis ◽  
One Pot ◽  
Room Temperature Synthesis ◽  
Mcm 41

Effect of the Reduction Temperature on Nickel Phosphide Catalyst Structure and Catalytic Activity for Hydrodesulfurization

2014 ◽  
Vol 1025-1026 ◽  
pp. 782-786 ◽  
Author(s):  
Hua Song ◽  
Fu Yong Zhang ◽  
Zai Shun Jin ◽  
Huai Yuan Wang ◽  
Yan Ji Zhu ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Fixed Bed ◽  
Space Velocity ◽  
Fixed Bed Reactor ◽  
Reduction Temperature ◽  
Catalyst Structure ◽  
X Ray ◽  
Weight Hourly Space Velocity ◽  
Transmission Electron ◽  
Nickel Phosphate

Ni2P/TiO2-Al2O3catalysts were prepared by impregnation of nickel phosphate precursors followed by reduction in hydrogen. The catalysts were characterized by X-ray diffraction (XRD), N2-adsorption specific surface area measurements (BET), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetry differential thermal analysis (TG-DTA). The effects of reduction temperature on catalyst structure and HDS activity were studied using a lab-scale continuous flow fixed-bed reactor.. The results indicated that the catalyst prepared with reduction temperature of 973 K exhibited the best performance. At a reaction temperature of 606 K, a pressure of 3.0 MPa, a hydrogen/oil ratio of 500 (V/V), and a weight hourly space velocity (WHSV) of 2.0 h-1, the conversion of DBT HDS was 96.0%.

Molecular Ionic Liquid Supported on Mesoporous Silica Nanoparticles-Imprinted Iron Metal: A Recyclable Heterogeneous Catalyst for One-Pot, Three-Component Synthesis of a Library of Benzodiazepines

2019 ◽  
Vol 16 (1) ◽  
pp. 136-144 ◽  
Author(s):  
Vajihe Nejadshafiee ◽  
Hossein Naeimi
Keyword(s):  
Ionic Liquid ◽  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
Mesoporous Silica Nanoparticles ◽  
One Pot ◽  
Environmental Friendliness ◽  
Iron Metal ◽  
Catalytic Cyclization ◽  
Recyclable Heterogeneous Catalyst ◽  
Mcm 41

Aim and Objective: A novel and convenient transformation for the synthesis of benzodiazepines has been developed via catalytic cyclization reaction using ionic liquid supported on mesoporous silica nanoparticles- imprinted iron metal (Fe-MCM-41-IL) as a recyclable catalyst under mild conditions. Materials and Methods: For preparation of Fe-MCM-41-IL, FeCl3·6H2O was added to a mixture of distilled water, CTAB and NaOH aqueous solution. The tetraethyl orthosilicate was dropped into the solution under stirring. The product was separated, washed, and dried. The solid product was collected and calcined. Then, to a solution of β-hydroxy-1,2,3-triazole in toluene, 3-chloropropyltrimethoxysilane was added and the mixture was refluxed. The Conc. H2SO4 was added dropwise into the above solution and stirred. For immobilization of IL onto Fe-MCM-41, the solution IL was added to Fe-MCM-41 and was refluxed for the production of the Fe- MCM-41. Following this, benzodiazepines were synthesized using Fe-MCM-41-IL as a catalyst. </P><P> Results: The Fe-MCM-41-IL was prepared and characterized by a different analysis. The activity of the prepared catalyst as the above described was tested in the model reaction of o-phenyldiamine, tetronic acid, and different aldehydes under room temperature in ethanol solvent. Also, the catalyst could be recovered for five cycles. Conclusion: We developed a novel nanocatalyst for the synthesis of benzodiazepines in excellent yields. Fe- MCM-41-IL as a catalyst has advantages such as: environmental friendliness, reusability and easy recovery of the catalyst using an external magnet.

Assessing the Catalytic Potential of 12-tungstophosphoric Acid Supported on MCM-41 for the Gas Phase Etherification of Alcohols

2017 ◽  
Vol 68 (7) ◽  
pp. 1442-1448
Author(s):  
Song Il Kong ◽  
Anca Borcea ◽  
Vasile Matei ◽  
Dragos Ciuparu
Keyword(s):  
Gas Phase ◽  
Flow Reactor ◽  
Space Velocity ◽  
Butyl Alcohol ◽  
Tungstophosphoric Acid ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Fuel Additive ◽  
Weight Hourly Space Velocity ◽  
Mcm 41

The gas-phase etherification reaction of ethanol with tert-butyl alcohol (TBA) was investigated for the production of an oxygenated fuel additive. The reaction was carried out in a continuous flow reactor, in the presence of 12-tungstophosphoric acid (HPW) dispersed on MCM-41 as catalyst. We have studied the influence of temperature, ethanol:TBA mole ratio, and weight hourly space velocity (WHSV) on the TBA conversion and ETBE selectivity. The optimum operating conditions were found at 110oC temperature, 8:1 ethanol:TBA mole ratio in the feed, and 30% HPW loading on the catalyst. The highest ETBE yield values were obtained at 110 �C and WHSV of 46 h-1 and 42 h-1. The HPW/MCM-41 catalyst showed good activity and on-stream stability for the gas-phase synthesis of ETBE at 110oC, thus it is a promising catalyst for etherification reactions and, potentially, for other gas phase acid-catalyzed reactions.

scholarly journals Preparation of bimetallic Ni–Fe/MCM-41 catalysts and their catalytic activity for CO methanation

2019 ◽  
Vol 45 ◽  
pp. 146867831987032
Author(s):  
Zhang Jiaying
Keyword(s):  
Bimetallic Catalysts ◽  
Space Velocity ◽  
Molar Ratio ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Activity Increase ◽  
Co Methanation ◽  
Weight Hourly Space Velocity ◽  
Temperature Programmed ◽  
Mcm 41

A series of Ni–Fe/MCM-41 bimetallic catalysts and also Ni/MCM-41 and Fe/MCM-41 catalysts were prepared by the incipient-wetness impregnation method and tested for their activity for CO methanation in a continuous-flow microreactor. The results showed that the catalytic activities of the Ni–Fe/MCM-41 bimetallic catalysts were much higher than those of the Ni/MCM-41 and Fe/MCM-41 catalysts at low temperatures (200°C–325°C). The 10%Ni–5%Fe/MCM-41 catalyst showed the best activity with a CO conversion of almost 100% and a CH4 selectivity of 98% at 350°C under a pressure of 1.5 MPa with a 3:1 molar ratio of H2 to CO and a weight hourly space velocity of 12,000 mL h−1 g−1. The catalysts were characterized by N2 physisorption measurements, X-ray diffraction, and H2-temperature-programmed reduction. The results showed that the addition of Fe will lead to the formation of finer Ni particles and Ni–Fe alloy, which were the main reasons for the activity increase in the Ni–Fe/MCM-41 catalysts.

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