scholarly journals MODIFIED COBALT CATALYSTS FOR HYDROGENATION OF HYDROCARBONS

2020 ◽  
Vol 18 (3) ◽  
pp. 156-161
Author(s):  
A.N. Aitugan ◽  
S.K. Tanirbergenova ◽  
Ye. Tileuberdi ◽  
D. Tugelbayeva
Keyword(s):  
Catalytic Activity ◽  
Aluminum Oxide ◽  
Process Parameters ◽  
Cobalt Catalyst ◽  
Cobalt Catalysts ◽  
Oxide Content ◽  
Acetylene Hydrogenation ◽  
Aluminum Oxides ◽  
Selective Hydrogenation Of Acetylene ◽  
Chemical Contents

This work is devoted to the study of the influence of aluminum oxide content on the activity of cobalt catalysts in the reaction of selective hydrogenation of acetylene to ethylene. Cobalt catalysts modified with aluminum oxide having size between 50 to 500 nm were synthesized. Chemical contents and structure of carrier were investigated.  The catalytic activity of 5 % Со /clay and 5% Co/SiAl catalysts at acetylene hydrogenation was studied in the temperature range 100-180 , with a ratio of 1:2 of acetylene and hydrogen. The ethylene yield is 87.8 % in modifying the cobalt catalyst with aluminum oxide, whereas with the same process parameters, the ethylene yield is 72 %. 5 % Cobalt catalysts modified with 1.5 % aluminum oxides are more active in hydrogenation acetylene process than 5 % Со /clay 450 ℃ catalyst.

scholarly journals OPTIMIZATION OF TECHNOLOGICAL PARAMETERS OF HYDRAGENERATION PROCESS OF ACETYLENE USING A PILOT CATALYTIC PLANT

2020 ◽  
Vol 5 (443) ◽  
pp. 134-140
Author(s):  
Tanirbergenova Sandugash Kudaibergenovna ◽  
◽  
Тugelbayeva Dildara Abdikadyrovna ◽  
Erezhep Nurzay ◽  
Zhylybayeva Nurzhamal Kydyrkhankyzy ◽  
...  
Keyword(s):  
Cobalt Catalyst ◽  
Space Velocity ◽  
Hydrogenation Reaction ◽  
Cobalt Catalysts ◽  
Side Reactions ◽  
Technological Parameters ◽  
Acetylene Hydrogenation ◽  
Before And After ◽  
Effects Of Temperature ◽  
Increasing Temperature

A pilot plant was launched and the modes of acetylene hydrogenation on cobalt catalysts were worked out. It has been found that the modified 7% Co/ SiAl cobalt catalyst is active in the process of hydrogenating acetylene into ethylene. Optimal conditions of acetylene hydrogenation on 7% Co/ SiAl catalyst were determined. The effects of temperature, space velocity and the ratio of initial components in the hydrogenation of acetylene to ethylene were investigated. The textural characteristics of cobalt catalysts before and after the hydrogenation of acetylene were investigated by the SEM method. The structure of cobalt catalysts after the hydrogenation of acetylene does not lose catalytic activity and selectivity. It has been found that catalyst samples have channels of different sizes, flaky particles and fibers located in the gaps between large aggregates are also present on the surface. The optimum temperature was 180 ° C in the hydrogenation of acetylene into ethylene at conversion 73.0%. Conversion of acetylene increases to 81.2% when temperature rises to 200°C, acetylene conversion decreases to 68% with further temperature exceeding to 220°C. Acetylene conversion again increases from 68 to 73.6% at 140°C in the ratio of acetylene to hydrogen 1:2. The selectivity of the catalyst 7%Co/SiAl to ethylene was studied depending on the temperature in the acetylene hydrogenation reaction. The selectivity to ethylene decreases with increasing temperature, since an increase in temperature activates side reactions.

Photocatalytic hydrogen generation using mesoporous silicon nanoparticles: influence of magnesiothermic reduction conditions and nanoparticle aging on the catalytic activity

Nanoscale ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 2685-2692
Author(s):  
Isabel S. Curtis ◽  
Ryan J. Wills ◽  
Mita Dasog
Keyword(s):  
Catalytic Activity ◽  
Hydrogen Production ◽  
Silicon Nanoparticles ◽  
Hydrogen Generation ◽  
Oxide Content ◽  
Magnesiothermic Reduction ◽  
Mesoporous Silicon ◽  
High Crystallinity ◽  
Photocatalytic Hydrogen Generation

High crystallinity, low oxide content, and low sintering lead to optimally performing mesoporous Si photocatalysts for solar-driven hydrogen production.

scholarly journals Synthesis, Characterization of Chitosan-Aluminum Oxide Nanocomposite for Green Synthesis of Annulated Imidazopyrazol Thione Derivatives

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1160
Author(s):  
Abir S. Abdel-Naby ◽  
Sara Nabil ◽  
Sarah Aldulaijan ◽  
Ibtisam M. Ababutain ◽  
Azzah I. Alghamdi ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Aluminum Oxide ◽  
Reaction Medium ◽  
Thiol Group ◽  
Docking Studies ◽  
Significant Loss ◽  
Gram Negative Bacteria ◽  
Organic Catalyst ◽  
Group 1

Chitosan-aluminum oxide nanocomposite was synthesized, characterized, and used as a green heterogeneous catalyst to synthesize novel imidazopyrazolylthione derivatives. Nanocomposite polymeric material was characterized by EDS-SEM and XRD. The powerful catalytic activity, and its base character of the nanocomposite, was used to synthesize imidazopyrazolylthione (1) in a good yield compared to traditional cyclocondensation synthesis. Using the nanocomposite catalyst, substitution of the thiol group (1) afforded the corresponding thiourea (2) and the corresponding ester (3). The efficiency of the nanocomposite over the traditional base organic catalyst, Et3N and NaOH, makes it an effective, economic, and reproducible nontoxic catalyst. Moreover, the heterogeneous nanocomposite polymeric film was easily isolated from the reaction medium, and recycled up to four times, without a significant loss of its catalytic activity. The newly synthesized derivatives were screened as antibacterial agents and showed high potency. Molecular docking was also performed for a more in-depth investigation. The results of the docking studies have demonstrated that the docked compounds have strong interaction energies with both Gram-positive and Gram-negative bacteria.

A carbonized cobalt catalyst supported by acid-activated clay for the selective hydrogenation of acetylene

2021 ◽  
Author(s):  
Aizat Aitugan ◽  
Sandugash Tanirbergenova ◽  
Yerbol Tileuberdi ◽  
Onuralp Yucel ◽  
Dildara Tugelbayeva ◽  
...  
Keyword(s):  
Selective Hydrogenation ◽  
Cobalt Catalyst ◽  
Selective Hydrogenation Of Acetylene ◽  
Acid Activated Clay

Influence of Process Parameters and Geometry of the Spraying Nozzle on the Properties of Titanium Deposits Obtained in Wire Arc Spraying

2015 ◽  
Vol 1111 ◽  
pp. 211-216
Author(s):  
Bogdan Florin Toma ◽  
Iulian Ionita ◽  
Diana Antonia Gheorghiu ◽  
Lucian Eva ◽  
Costică Bejinariu ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Process Parameters ◽  
High Speed ◽  
Electrical Current ◽  
Electric Arc ◽  
Arc Spraying ◽  
Oxide Content ◽  
Spray Parameters ◽  
Influence Of Process Parameters ◽  
Wire Arc Spraying

Influence of the process parameters and geometry of the spraying nozzle on the properties of titanium deposits obtained in wire arc spraying. Wire arc spraying is a process in which through minor modifications of the spray parameters, they can have a major impact on the coatings properties. In this paper there is presented a study on the influence of process parameters and fluid dynamics of the atomization gas on the properties of titanium deposits (14T - 99.9% Ti). For this there were used three different frontal spraying nozzles, having different geometries, and were varied the spraying gas pressure and the electrical current on three levels. There were evaluated the particles velocity, coating density, chemical composition and characteristic interface between deposition and substrate. Obviously, the high speed of the atomization gas determinate the improving of all properties, but in the same time increased the oxide content in the layer. However, the oxidation can be drastically reduced if the melting and atomization of the wire droplets is produced at the point of formation of the electric arc, and the spraying jet is designed to constrain the electric arc. The assessment of deposits adherence allowed the observation of process parameters that contribute to its improvement.

Effect of co-existing copper and calcium on the removal of As(V) by reused aluminum oxides

2013 ◽  
Vol 67 (1) ◽  
pp. 187-192
Author(s):  
J. K. Yang ◽  
Y. J. Park ◽  
K. H. Kim ◽  
H. Y. Lee ◽  
K. C. Min ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Binary System ◽  
Aluminum Oxide ◽  
Aqueous Solutions ◽  
Copper Concentration ◽  
Calcium Concentration ◽  
Environmental Fate ◽  
Mine Drainage ◽  
Aluminum Oxides ◽  
Molar Ratios

Among the various heavy metals, arsenic is frequently found in abandoned mine drainage and the environmental fate of arsenic in real aqueous solutions can be highly dependent on the presence of co-existing ions. In this study, removal of arsenate through adsorption on the reused aluminum oxide or through precipitation was investigated in a single and in a binary system as a function of pH and concentration. Different removal behaviors of arsenate were observed in the presence of different cations as well as a variation of the molar ratios of arsenate to cations. Co-operative effects on arsenate removal by precipitation in solution occurred with an increase of copper concentration, while a decrease of arsenate removal resulted in increasing calcium concentration. It was observed that the arsenate removal in the presence of calcium would be highly dependent on the molar ratios of both elements.

Synthesis of Isopulegol Through Cyclisation of Citronellal Using Solid Acid Catalysts: Catalytic Reaction Performance Evaluation and Process Parameters Optimization

2021 ◽  
Vol 22 (2) ◽  
pp. 252-263
Author(s):  
Abdul Karim Shah ◽  
Ghulam Abbas Kandhro ◽  
Aqeel Ahmed Shah ◽  
Syed Nizam Uddin Shah Bukhari ◽  
Arshad Iqbal ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Process Parameters ◽  
Acid Treatment ◽  
Research Work ◽  
Intermediate Stage ◽  
Catalytic Performance ◽  
Montmorillonite Clay ◽  
Parameters Optimization ◽  
Reaction Performance ◽  
Montmorillonite Catalyst

The cyclisation of citronellal to isopulegol is a significant intermediate stage in the production of menthols. In this research work, the effects of acid treatment on montmorillonite clay have been investigated and used in citronellal cyclisation reactions. Furthermore, the effects of acid treatment and hetero-poly acid impregnation have been determined on the textural and catalytic properties of montmorillonite clay. The designed catalysts were characterized by XRD, N2 sorption, and NH3- TPD techniques. Acid treatment of montmorillonite resulted in the enhancement of surface area and pore volume. The catalytic activity and selectivity parameters were lessened due to the severe leaching of Al ions from tetrahedral crystalline structures (e.g., weakened structure and loss of acidity). Among all prepared materials, the heteropoly acid supported HCl treated montmorillonite catalyst was observed as a more active, stable, and selective catalyst that showed the highest catalytic performance in citronellal cyclisation under optimized process parameters. The catalytic activity and selectivity were enhanced with rising mesoporosity and acidity parameters due to HCl acid treatment and HPA impregnation.

scholarly journals Selective Hydrogenation of Acetylene Catalysed by a B12N12 Cluster Doped with a Single Nickel Atom: A DFT Study

Catalysts ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 115 ◽  
Author(s):  
Yun Wang ◽  
Lihua Kang
Keyword(s):  
Selective Hydrogenation ◽  
Density Functional ◽  
Reaction Path ◽  
Nickel Atom ◽  
Single Atom ◽  
Functional Theory ◽  
Acetylene Hydrogenation ◽  
Selective Hydrogenation Of Acetylene ◽  
New Type ◽  
Catalytic Performances

To obtain a catalyst based on a non-precious metal that can replace traditional palladium-based selective catalysts of acetylene hydrogenation, the catalytic performances of two different configurations of a B12N12 cluster doped with a single nickel atom were studied by a density functional theory computational approach. After analysing the effect that the adsorption of reactants onto the clusters has on the reaction path, we determined the lowest energy path for the acetylene double hydrogenation. Comparing the acetylene hydrogenation activities and ethylene product selectivities of the B11N12Ni and B12N11Ni clusters, which have different doping sites, we determined the activities of these two catalysts to be similar to each other; however, the B11N12Ni cluster was calculated to have higher selectivity for ethylene as a product. This difference may be related to the moderate adsorption of hydrogen and acetylene on the B11N12Ni cluster. As a new type of nickel-based single-atom catalyst, B11N12Ni clusters may have research value in the selective hydrogenation of acetylene.

scholarly journals Boron adsorption in soils from the State of São Paulo, Brazil

2000 ◽  
Vol 35 (2) ◽  
pp. 413-421 ◽  
Author(s):  
LUÍS REYNALDO FERRACCIÚ ALLEONI ◽  
OTÁVIO ANTONIO DE CAMARGO
Keyword(s):  
Aluminum Oxide ◽  
Correlation Coefficients ◽  
Clay Content ◽  
Sao Paulo ◽  
The State ◽  
São Paulo ◽  
Aluminum Oxides ◽  
Freundlich Isotherms ◽  
Physical Attributes ◽  
Boron Adsorption

Boron adsorption was studied in five representative soils (Rhodic Hapludox, Arenic Paleudalf and three Typic Hapludox) from the State of São Paulo, Brazil. Adsorption was higher in the clayey Oxisols, followed by the Alfisol and the coarser Oxisols. Calcium carbonate promoted an increase in the amount of adsorbed boron in all soils, with the most pronounced effect in the coarser-textured Oxisols. High correlation coefficients were found between adsorbed boron and clay and amorphous aluminum oxide contents and specific surface area (r = 0.79, 0.76 and 0.73, respectively, p < 0.01). Clay content, free aluminum oxide, and hot CaCl2 (0.01 mol L-1)-extracted boron explained 93% of the variation of adsorbed boron. Langmuir and Freundlich isotherms fitted well to the adsorbed data, and highest values for maximum boron adsorption were found in clayey soils, which were significantly correlated with contents of total, free and amorphous iron and aluminum oxides, as well with the physical attributes. Ninety four percent of the variation in the maximum adsorption could be related to the free iron content.

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