scholarly journals Tris(2-Aminoethyl)Amine/Metal Oxides Hybrid Materials—Preparation, Characterization and Catalytic Application

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4689
Author(s):  
Katarzyna Stawicka ◽  
Maria Ziolek
Keyword(s):  
Metal Oxide ◽  
Metal Oxides ◽  
Hybrid Materials ◽  
Knoevenagel Condensation ◽  
Catalyst Activity ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Surface Areas ◽  
Strength Of Interaction ◽  
Adsorption Desorption

Three different metal oxides (basic MgO, basic-acidic Al2O3 and acidic-basic Nb2O5) characterized by comparable surface areas (MgO—130 m2/g; Al2O3—172 m2/g and Nb2O5—123 m2/g) and pore systems (domination of mesopores with narrow pore size distribution) were modified with tris(2-aminoethyl)amine (TAEA) via two methods: (i) direct anchoring of amine on metal oxide and (ii) anchoring of amine on metal oxide functionalized with (3-chloropropyl)trimethoxysilane. The obtained hybrid materials were characterized in terms of effectiveness of modifier anchoring (elemental analysis), their structural/textural properties (nitrogen adsorption/desorption, XRD), acidity/basicity of support (2-propanol dehydration and dehydrogenation, dehydration and cyclization of 2,5-hexanedione), states of modifier deposited on supports (XPS, FTIR, UV–VIS) and the strength of interaction between the modifier and the support (TG/DTG). It was evidenced that acidic-basic properties of metal oxides as well as the procedure of modification with TAEA determined the ways of amine anchoring and the strength of its interaction with the support. The obtained hybrid materials were tested in Knoevenagel condensation between furfural and malononitrile. The catalysts based on MgO showed superior activity in this reaction. It was correlated with the way of TAEA anchoring on basic MgO and the strength of modifier anchoring on the support. To the best of our knowledge tris(2-aminoethyl)amine has not been used as a modifier of solid supports for enhancement of the catalyst activity in Knoevenagel condensation.

Structural and surface aspects of thermally treated copper aluminium mixed hydroxides

1991 ◽  
Vol 69 (10) ◽  
pp. 1511-1515 ◽  
Author(s):  
Awad I. Ahmed ◽  
S. E. Samra ◽  
S. A. El-Hakam
Keyword(s):  
Pore Structure ◽  
Copper Content ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Structure Surface ◽  
Adsorption Desorption

CuO–Al2O3 catalysts containing various amounts of copper oxide have been prepared by precipitation. The phase changes were studied by X-ray diffraction. The results obtained revealed that the thermal treatment of solid CuO–Al2O3 at 700 °C produced only crystalline CuO. Heating to 900 °C led to the formation of copper alumina spinel together with unreacted CuO and γ-Al2O3. The spinel content was found to increase with increasing copper content. Nitrogen adsorption–desorption isotherms on the calcined samples have been measured. Surface areas have been calculated and the pore structure analysed. The textural properties of the system were found to depend on both the copper content and the calcination temperature. Key words: CuO, Al2O3 catalysts, structure, surface area, pore structure.

Study of the catalytic activity of Al-Fe pillared clays in the Baeyer–Villiger oxidation

Clay Minerals ◽  
2012 ◽  
Vol 47 (2) ◽  
pp. 275-284 ◽  
Author(s):  
L. S. Belaroui ◽  
A. Bengueddach
Keyword(s):  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Pillared Clays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dissolved Iron ◽  
Surface Areas ◽  
Accessible Surface ◽  
Adsorption Desorption ◽  
Villiger Oxidation

AbstractThree types of AlFePILCs pillared clays have been prepared from Algerian clay precursors. They have been characterized and tested in the Baeyer–Villiger oxidation of cyclohexanone to caprolactone using benzaldehyde and oxygen as oxidant at room temperature. The structural and textural properties of the catalyst have been determined by X-ray diffraction, nitrogen adsorption-desorption isotherms and Mössbauer spectroscopy.The different activities of the clays have been related to their Fe contents and accessible surface areas. The induction period observed before the reaction started has been attributed to the dissolution of a portion of the Fe3+ cations, mediated by either the perbenzoic acid intermediate or the benzoic acid co-product. The reaction was indeed catalysed by a few ppm of dissolved iron cations and the catalysis of the Baeyer–Villiger oxidation reaction should mechanistically be considered as homogeneous.

scholarly journals Silver nanoparticles deposited on pyrogenic silica solids: Preparation and textural properties

2017 ◽  
Vol 35 (7-8) ◽  
pp. 714-720 ◽  
Author(s):  
M Zienkiewicz-Strzałka ◽  
M Błachnio ◽  
A Deryło-Marczewska ◽  
RB Kozakevych ◽  
YM Bolbukh ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Silicon Dioxide ◽  
Noble Metal ◽  
Materials Science ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Nanostructured Material ◽  
Scanning Calorimetry ◽  
Adsorption Desorption ◽  
Pyrogenic Silicon Dioxide

Silver-based nanomaterials and composites are important components in materials science and engineering due to the reactivity of silver nanophase based on exceptional surface effects. Ag-doped SiO2 nanocomposites were synthesized by wet impregnation procedure of aminopropyl-functionalized silica materials with submicrometer structure. Aminopropyl-functionalized pyrogenic silicon dioxide with amount of amino groups established as half and close to full monolayer was used to immobilize the nanosilver phase obtained from ammoniacal silver complex as a noble metal precursor. Pyrogenic silicon dioxide as an inexpensive nanostructured material with useful properties including adsorptive affinity for noble metal ions and organic macromolecules was applied as a support for diamminesilver(I) ions and finally for silver nanoparticles. In the present study, the effect of amino-functionalization and silver nanoparticles deposition was monitored by investigation of the textural properties and thermal stability of obtained nanocomposites. The properties of the nanocomposites were investigated by transmission electron microscopy, nitrogen adsorption–desorption isotherms, and thermal analysis (thermogravimetry/differential scanning calorimetry).

Synthesis of SBA-15 under Normal Pressure by Microwave Irradiation Method for Adsorption of Pb(II) in Environment

2010 ◽  
Vol 113-116 ◽  
pp. 775-779 ◽  
Author(s):  
Yan Liu ◽  
Yun Wang ◽  
Xiao Jie Zhang ◽  
Ji Min Xie ◽  
Yong Sheng Yan
Keyword(s):  
Microwave Irradiation ◽  
River Sediments ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Normal Pressure ◽  
X Ray Diffraction ◽  
Microwave Irradiation Method ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Adsorption Desorption

Mesoporous silica SBA-15 has been prepared rapidly under normal pressure by microwave irradiation method. The textural properties were studied by low-angle X-ray diffraction (XRD) and nitrogen adsorption-desorption. The optimum adsorption conditions of Pb(Ⅱ) on SBA-15 was investigated. The results show that the adsorption kinetics follows a pseudo-second-order rate model and the experimental equilibrium data is fitted well by Langmuir adsorption isotherm. The adsorption capacity reaches 50.10 mg•g-1 which is much higher than that of hydrothermal synthesized samples. This adsorbent has been applied in the determination of Pb(Ⅱ) in river sediments samples.

scholarly journals Cyclic voltammetric study of the influence of porosity on electrochemical response of nickel-alumina modified glassy carbon electrode

2018 ◽  
Vol 50 (3) ◽  
pp. 313-321
Author(s):  
Ana Ivanovic-Sasic ◽  
Tatjana Novakovic ◽  
Zorica Mojovic ◽  
Zeljko Cupic ◽  
Dusan Jovanovic
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Modified Electrodes ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Carbon Electrode ◽  
Modified Glassy Carbon Electrode ◽  
Cyclic Voltammetric ◽  
Cyclic Voltammetric Study ◽  
Adsorption Desorption

Pure and nickel-modified alumina powders with different porosity were synthesized and applied on the glassy carbon electrode by means of Nafion polymer. The data obtained from the nitrogen adsorption-desorption isotherm confirmed that the pore structures in these materials are complex and tend to be made up of interconnected networks of pores of different size and shape. The addition of Ni2+ ions caused the changes in the textural properties of the samples. The influence of porosity on the electrochemical behavior of modified electrodes in quasi-reversible process was tested by cyclic voltammetry. Numerical correlations between electrochemical responses of GCE modified with alumina samples and textural properties have been established.

scholarly journals Oxidation of Carbon Monoxide Over Alumina-supported Metal Oxide Catalysts

1995 ◽  
Vol 12 (4) ◽  
pp. 335-343 ◽  
Author(s):  
A.M. Youssef ◽  
E.A. El-Sharkawy
Keyword(s):  
Carbon Monoxide ◽  
Metal Oxide ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Chemical Compositions ◽  
Calcination Temperatures ◽  
Characteristic Lines ◽  
Different Temperatures ◽  
Supported Metal Oxide ◽  
Oxidation Of Carbon Monoxide

Catalysts of the type CuO/Al2O3, NiO/Al2O3 and Co3O4/Al2O3 with different chemical compositions and subjected to different calcination temperatures were prepared using the impregnation technique. The crystal structure of the calcination products was determined by X-ray diffraction (XRD) while the textural properties were determined from nitrogen adsorption at 77 K. The activity of the catalysts towards the oxidation of carbon monoxide with O2 at different temperatures was also investigated. XRD indicated that calcination of these systems at ≤1073 K did not lead to the formation of spinel. Moreover, no characteristic lines indicating the existence of any metal oxide were observed when the concentration of the latter was less than 10 mol%. The catalytic oxidation of CO followed first-order kinetics with the catalytic activity depending on the metal oxide loading and its dispersion on the surface of the alumina. In most cases, Co3O4/Al2O3 catalysts exhibited the highest activity.

scholarly journals Synthesis and use of carvedilol metal complexes as carbon dioxide storage media

2020 ◽  
Vol 10 (3) ◽  
pp. 157-164
Author(s):  
Omar G. Mousa ◽  
Emad Yousif ◽  
Ahmed A. Ahmed ◽  
Gamal A. El‐Hiti ◽  
Mohammad Hayal Alotaibi ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Metal Complexes ◽  
Copper Complexes ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Carbon Dioxide Storage ◽  
Small Surface ◽  
Carbon Dioxide Uptake ◽  
Storage Media ◽  
Adsorption Desorption

Abstract The consequences of increased fossil fuel consumption on the environment presents a challenge. Carbon dioxide capture is a useful technique to reduce global warming. Therefore, three carvedilol metal (nickel, cobalt, and copper) complexes were synthesized as potential carbon dioxide storage media. The structural and textural properties of metal carvedilol complexes have been established using various techniques. The metal complexes have mesoporous structures in which pore size was approximately 3 nm. Particle size ranged from 51.0 to 393.9 nm with a relatively small surface area (6.126–9.073 m2/g). The carvedilol metal complexes have either type-III or IV nitrogen adsorption–desorption isotherm. The complexes showed reasonable capacity towards carbon dioxide uptake (up to 18.21 cm3/g) under the optimized condition (40 bar and 323 K). Graphical Abstract

Reaction of iodine with metal oxides

2011 ◽  
Vol 89 (11) ◽  
pp. 1370-1374 ◽  
Author(s):  
Marek Gliński ◽  
Urszula Ulkowska
Keyword(s):  
Experimental Data ◽  
Metal Oxide ◽  
Metal Oxides ◽  
Vapour Phase ◽  
Basic Sites ◽  
Strength Of Interaction

The reaction of iodine with various metal oxides has been studied in both vapour phase (373–873 K) and in solution in cyclohexane, under anhydrous conditions. The course of the reaction has been revised in accordance with literature and experimental data. Apart from adsorbed iodine molecules ([I2] < 200 μmol·g–1), the presence of I– ions ([I–] < 50 μmol·g–1) has been noted. IOn– ions have been observed only when both water and strong basic sites, such as those on MgO or La2O3, are present. It has been found that the strength of interaction of iodine with metal oxide increases with basicity of the oxide.

MESOPOROUS CARBON ELECTRODE: SYNTHESIS, CHARACTERIZATION AND ELECTROCHEMICAL PROPERTIES

2010 ◽  
Vol 03 (03) ◽  
pp. 161-164 ◽  
Author(s):  
XI LONG ◽  
CHUNXIA ZHAO ◽  
WEN CHEN
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Properties ◽  
Mesoporous Carbon ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Constant Current ◽  
Surface Areas ◽  
Constant Current Charge ◽  
Adsorption Desorption ◽  
Charge Discharge

The present paper studies a kind of mesoporous carbon (MC) with high electrochemical performance, which was prepared by vapor infiltration method. The microstructure and electrochemical properties of the mesoporous carbon were investigated by transmission electron microscopy (TEM), nitrogen adsorption–desorption isotherms, cyclic voltammetry (CV), constant current charge–discharge cycling (CD), and the long-term stability test. The results indicated that the mesoporous carbon has an ordered mesoporous structure, with pore size of about 3.87 nm and surface areas of 1087 m2 ⋅ g-1. The cyclic voltammetry curve reveals typical electrical double-layer capacitor property. After 200 cycles, the CV curves can almost be overlapped, which indicates excellent cycling stability. From the charge/discharge cycling, the specific capacitance of MC is 117 F ⋅ cm-1 in 1.0 M KNO3 electrolyte media at a scan rate of 1.0 mV ⋅ s-1, which decays with increasing current density. The charge–discharge efficiency also decays with it.

scholarly journals Sorption of Methylene Blue for Studying the Specific Surface Properties of Biomass Carbohydrates

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1115
Author(s):  
Tatiana Skripkina ◽  
Ekaterina Podgorbunskikh ◽  
Aleksey Bychkov ◽  
Oleg Lomovsky
Keyword(s):  
Methylene Blue ◽  
Specific Surface ◽  
Surface Area ◽  
Surface Characterization ◽  
Gas Adsorption ◽  
Comparative Method ◽  
Nitrogen Adsorption ◽  
Surface Areas ◽  
Nitrogen Adsorption Isotherms ◽  
Adsorption Desorption

The surface area is an important parameter in setting any biorefining technology. The aim of this study was to investigate the applicability of sorption of methylene blue to characterize the surface of the main biomass carbohydrates: α-cellulose, sigmacell cellulose, natural gum, β-glucan, and starch. The morphology of particles of the model objects was studied by scanning electron microscopy. Nitrogen adsorption isotherms demonstrate that the selected carbohydrates are macroporous adsorbents. The monolayer capacities, the energy constants of the Brunauer–Emmett–Teller (BET) equation, and specific surface areas were calculated using the BET theory, the comparative method proposed by Gregg and Sing, and the Harkins–Jura method. The method of methylene blue sorption onto biomass carbohydrates was adapted and mastered. It was demonstrated that sorption of methylene blue proceeds successfully in ethanol, thus facilitating surface characterization for carbohydrates that are either soluble in water or regain water. It was found that the methylene blue sorption values correlate with specific surface area determined by nitrogen adsorption/desorption and calculated from the granulometric data. As a result of electrostatic attraction, the presence of ion-exchanged groups on the analyte surface has a stronger effect on binding of methylene blue than the surface area does. Sorption of methylene blue can be used in addition to gas adsorption/desorption to assess the accessibility of carbohydrate surface for binding large molecules.

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