scholarly journals Fast Synthesis of Co3O4 by Microwave-Assisted Hydrothermal Treatment

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Midilane S. Medina ◽  
Alessandra Zenatti ◽  
Marcia T. Escote
Keyword(s):  
Magnetic Measurements ◽  
Simple Procedure ◽  
Particle Morphology ◽  
Weak Ferromagnetism ◽  
Oxidizing Agent ◽  
Synthesis Time ◽  
Microwave Assisted ◽  
Crystallite Sizes ◽  
Paramagnetic Behaviour ◽  
Size And Morphology

This work describes a fast and simple procedure that combines the virtues of the microwave-assisted hydrothermal method with an oxidizing agent to produce Co3O4 nanocubes and nanoplates. We observed that particle morphology and size depend on the synthesis time and oxidizing agent (urea and hydrogen peroxide). The X-ray diffraction results showed that the samples are single phase, with crystallite sizes of approximately 30 nm. A similar crystalline domain is observed in the transmission electronic images. Magnetic measurements revealed the influence of the size and morphology of the particles on the magnetic curves. These measurements on the nanoplate samples revealed a paramagnetic behaviour at higher temperatures, and the presence of a cusp at that temperature was defined as TP. The TP decreases from 36 K to 21 K when the size of the plate particles decreases from ~70 nm to 10 nm. These samples also present weak ferromagnetism below TP, which is attributed to a superparamagnetic blockade state. The nanocube samples have a lower magnetic susceptibility magnitude and weak ferromagnetism behaviour at room temperature. Our results show that this synthesis produces Co3O4 nanoplates and nanocubes with interesting magnetic properties related to their shape and size.

Nitroxide radicals appended to phthalonitriles: synthesis, structural characterization and photophysical properties

2021 ◽  
Vol 77 (3) ◽  
pp. 137-143
Author(s):  
Ismail Fidan ◽  
Emel Onal ◽  
Catherine Hirel
Keyword(s):  
Magnetic Measurements ◽  
Photophysical Properties ◽  
Nucleophilic Aromatic Substitution ◽  
Structural Studies ◽  
Aromatic Substitution ◽  
Nitronyl Nitroxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Assisted ◽  
Ft Ir

The syntheses of 4-[4-(4,4,5,5-tetramethyl-2-imidazoline-3-oxide-1-oxyl-2-yl)phenoxy]phthalonitrile (3, C21H19N4O3) and 4-[4-(4,4,5,5-tetramethyl-2-imidazoline-1-oxyl-2-yl)phenoxy]phthalonitrile (4) were carried out by microwave-assisted nucleophilic aromatic substitution of 4-nitrophthalonitrile (2) by the pre-formed 2-(4-hydroxyphenyl)-4,4,5,5-tetramethyl-2-imidazoline-3-oxide-1-oxyl (1). Compounds 3 and 4 were characterized unambiguously by a rich array of analyses, such as melting point, FT–IR, MALDI–TOF MS, elemental analysis, UV–Vis, CV, EPR, magnetic measurements and single-crystal X-ray diffraction. Structural studies demonstrate that the C—H...X and C—X...π (X = O and N) interactions in the radical nitronyl nitroxide groups play an important role in the assembly of the crystal structures. Moreover, cyclic voltammetry analyses show that the phthalonitrile substituent retains the redox properties of the Ullman radicals.

scholarly journals Synthesis of Hydroxy Sodalite from Coal Fly Ash for Biodiesel Production from Waste-Derived Maggot Oil

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1052 ◽  
Author(s):  
Juvet Malonda Shabani ◽  
Omotola Babajide ◽  
Oluwaseun Oyekola ◽  
Leslie Petrik
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Synthesis Method ◽  
Industrial Applications ◽  
Biodiesel Production ◽  
Synthesis Time ◽  
Crystalline Materials ◽  
Ft Ir ◽  
Size And Morphology ◽  
Gradual Variation

Zeolites are aluminosilicate crystalline materials known for their unique characteristics, and have been prominent for nearly half a century due to their wide and important industrial applications. The production of zeolites, however, remains a challenge due to the high cost of commercial reagents conventionally used as feedstocks. In the current study, hydroxy sodalite (HS) zeolite samples were synthesised from coal fly ash feedstock by a direct hydrothermal synthesis method. The effects of hydrothermal crystallisation synthesis time on phase crystallinity, crystal size, and morphology of the formed HS were investigated. The prepared samples were characterised using XRD, SEM, EDS and FT-IR techniques. The XRD results of the samples prepared with varying synthesis times confirmed the formation of HS from low to high phase purity and crystallinity from 11 to over 98%. The SEM results reflected gradual variation in crystal morphology, of which highly crystalline HS samples were associated with hexagonal-cubic and cubic-platelet crystals. The FTIR, depicting zeolite characteristics of T–O and T–O–T stretching vibrations in the molecular framework, further confirmed the formation of HS zeolites for samples obtained above the 24-h synthesis time. These zeolite samples were then evaluated for their catalytic activities in the conversion of maggot oil to biodiesel. The application of the various hydroxy sodalite samples for the transesterification of maggot oil yielded up to 84.10% biodiesel (FAME) with physicochemical properties that were in compliance with the biodiesel specification standards. This study investigated the novel use of a coal fly ash-derived, heterogeneous HS catalyst in biodiesel production from maggot oil, and indicates its potential to enhance biodiesel yield and quality upon process optimisation tests.

scholarly journals Novel Microwave-Assisted Method of Y2Ti2O7 Powder Synthesis

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5621
Author(s):  
Vladimir Chishkala ◽  
Serhiy Lytovchenko ◽  
Bohdan Mazilin ◽  
Edwin Gevorkyan ◽  
Vladimir Shkuropatenko ◽  
...  
Keyword(s):  
Energy Savings ◽  
High Energy ◽  
Industrial Applications ◽  
Powder Synthesis ◽  
Microwave Assisted ◽  
Pyrochlore Type ◽  
Size And Morphology ◽  
Solvent Chemistry ◽  
The Cost ◽  
Microwave Assisted Method

In the paper, a novel technique for highly dispersed pyrochlore Y2Ti2O7 is proposed. The experimental results proved that the application of microwave irradiation at a certain stage of calcination allowed synthesizing of Y2Ti2O7 in much shorter time, which ensured substantial energy savings. An increase up to 98 wt.% in the content of the preferred phase with a pyrochlore-type structure Y2Ti2O7 was obtained after 25 h of yttrium and titanium oxides calcination at a relatively low temperature of 1150 °C, while the microwave-supported process took only 9 h and provided 99 wt.% of pyrochlore. The proposed technology is suitable for industrial applications, enabling the fabrication of large industrial amounts of pyrochlore without solvent chemistry and high-energy mills. It reduced the cost of both equipment and energy and made the process more environmentally friendly. The particle size and morphology did not change significantly; therefore, the microwave-assisted method can fully replace the traditional one.

Synthesen, Kristallstrukturen und magnetische Eigenschaften von [Li(12-Krone-4)2][Li(12-Krone-4)(OH2)]2[Nb6Cl18], [Li(15-Krone-5)2(OH2)]3[Nb6Cl18] und [(18-Krone-6)2(O2H5)]3[Nb6Cl18] / Syntheses, Crystal Structures and Magnetic Behaviour of [Li(12-Krone-4)2][Li(12-Krone-4)(OH2)]2[Nb6Cl18], [Li(15-Krone-5)2(OH2)]3[Nb6Cl18] and [(18-Krone-6)2(O2H5)]3[Nb6Cl18]

2001 ◽  
Vol 56 (10) ◽  
pp. 1025-1034 ◽  
Author(s):  
Markus Ströbele ◽  
H.-Jtirgen Meyer
Keyword(s):  
Crystal Structure ◽  
Water Molecule ◽  
Crown Ethers ◽  
Magnetic Measurements ◽  
Structure Refinement ◽  
Magnetic Behaviour ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Paramagnetic Behaviour

The title compounds were prepared through reactions of Li2Nb6Cl16 with the corresponding crown ethers in acetone. All three compounds were obtained as dark brown crystals. Their structures were solved with the means of single-crystal X-ray diffraction.[Li(12-crown-4)2][Li(12-crown-4)(OH2)]2[Nb6Cl18]: space group P21/n, Z =2, a = 1320.4(1), b = 1879.1(1), c = 1321.7(1) pm, ß = 92.515(6)°, R1 = 0.0297 (I>2σ(I)). The crystal structure contains Li+ sandwiched by two 12-crown-4-ethers plus Li+ coordinated by one 12-crown-4- ether and one water molecule.[Li(15-crown-5)2(OH2)]3[Nb6Cl18]: space group R3̅, Z = 3, a = b = 2081.7(1), c = 1991.7(1) pm, R1 = 0.0395 (I > 2σ(I)). In the crystal structure Li+ and one water molecule are sandwiched by two 15-crown-5-ethers.[(18-crown-6)2(O2H5)]3[Nb6Cl18]: space group P1̅, Z = 1 ,a = 1405.1(1), b = 1461.1(2), c = 1492.2(2) pm; α = 98.80(1)°, ß = 98.15(1)°, γ = 97.41(1)°, R1 = 0.0538 (I > 2σ(I)). H5O2+ was found in the structure refinement sandwiched between two 18-crown-6-ethers.All compounds reported contain [Nb6Cl18] clusters with Nb-Nb distances between 299 and 301 pm. The paramagnetic behaviour expected for [Nb6Cl18]3- in all three compounds was confirmed by magnetic measurements.

scholarly journals Mechanochemical synthesis of bismuth ferrite

2013 ◽  
Vol 49 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Z. Marinkovic-Stanojevica ◽  
L. Mancic ◽  
T. Sreckovic ◽  
B. Stojanovic
Keyword(s):  
Milling Time ◽  
Structure Refinement ◽  
Bismuth Ferrite ◽  
Renewable Energy Sources ◽  
Microstructural Analysis ◽  
Three Dimensional ◽  
Conventional Solid State Reaction ◽  
Refinement Method ◽  
Crystallite Sizes ◽  
Size And Morphology

A powder mixture of Bi2O3 and Fe2O3 was mechanically treated in a planetary ball mill in an air from 30 to 720 minutes. It was shown that the mechanochemical formation of BiFeO3 (BFO) phase was initiated after 60 min and its amount increased gradually with increasing milling time. A detailed XRPD structural analysis is realized by Rietveld?s structure refinement method. The resulting lattice parameters, relative phase abundances, crystallite sizes and crystal lattice microstrains were determined as a function of milling time. Microstructural analysis showed a little difference in morphology of obtained powders. The primary particles, irregular in shape and smaller than 400 nm are observed clearly, although they have assembled together to form agglomerates with varying size and morphology. Dense BFO ceramics were prepared by conventional solid-state reaction at the temperature of 810?C for 1h followed immediately by quenching process. [Projekat Ministarstva nauke Republike Srbije, br. III45007: Zero- to Three-Dimensional Nanostructures for Application in Electronics and Renewable Energy Sources: Synthesis, Characterization and Processing

scholarly journals Byphenyl Hydrazone@SiO2 Composite: Synthesis and Evaluation of a New Chemosensor System for the Detection of Cu2+

Proceedings ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 39
Author(s):  
Vanina A. Guntero ◽  
Carla M. Ormachea ◽  
Pedro M. E. Mancini ◽  
Cristián A. Ferretti ◽  
María N. Kneeteman
Keyword(s):  
Mesoporous Silica ◽  
Simple Procedure ◽  
Physicochemical Characterization ◽  
Hydrazone Ligand ◽  
Microwave Assisted ◽  
Mesoporous Sio2 ◽  
Composite Synthesis

In the present work a byphenyl hydrazone/SiO2 composite was synthetized by a simple procedure. First, the mesoporous SiO2 and the byphenyl hydrazone ligand were prepared. To prepare the composite, the mesoporous silica and the ligand were dispersed in ethanol/water by a microwave assisted process. Then, the composite was characterized by different techniques to evaluate its chemosensor properties. The physicochemical characterization of the composite confirmed the selectivity and sensitive capacity to detect Cu+2 ions.

Molten Salt Synthesis of CaCu3Ti4O12

2008 ◽  
Vol 368-372 ◽  
pp. 115-117 ◽  
Author(s):  
Ke Pi Chen ◽  
Yong He ◽  
Dong Yu Liu ◽  
Zong De Liu
Keyword(s):  
Particle Size ◽  
Molten Salt ◽  
Average Particle Size ◽  
Particle Morphology ◽  
Holding Time ◽  
Molten Salt Synthesis ◽  
Average Particle ◽  
Molten Salt Method ◽  
Particle Size Analyzer ◽  
Size And Morphology

CCTO powders were prepared by using molten salt method in the NaCl-KCl system. The effects of temperature and holding time on phase compositions, particle morphology and size have been investigated by X-ray diffraction, scanning electron microscope and laser particle size analyzer. Using CaCO3, CuO and TiO2 as starting materials, CCTO compound could be synthesized at any temperature from 800oC to 1000oC in the NaCl-KCl system. The average particle size increased obviously with the increasing of temperature above 850 oC. Holding time had great effect on grain size and morphology.

scholarly journals Microwave-assisted synthesis of isoindolinones via Pd-mediated tandem coupling reactions

2018 ◽  
Vol 24 (3) ◽  
pp. 129-133
Author(s):  
Eduardo Mendoza-Pérez ◽  
Alfredo Vázquez
Keyword(s):  
Organic Chemistry ◽  
Simple Procedure ◽  
Boronic Acids ◽  
Microwave Assisted Synthesis ◽  
Coupling Reactions ◽  
Synthetic Organic Chemistry ◽  
Microwave Assisted ◽  
Tandem Process ◽  
Indispensable Tool

AbstractPalladium (Pd) coupling reactions have become an indispensable tool in modern synthetic organic chemistry. A simple procedure to obtain isoindolinones 7 bearing a quaternary C-atom, featuring a Pd-mediated tandem process, is presented. Readily available iodoamidoacrylate 3 and boronic acids 6 are used as the starting materials.

scholarly journals Recent Trends in the Microwave-Assisted Synthesis of Metal Oxide Nanoparticles Supported on Carbon Nanotubes and Their Applications

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Sarah C. Motshekga ◽  
Sreejarani K. Pillai ◽  
Suprakas Sinha Ray ◽  
Kalala Jalama ◽  
Rui. W. M. Krause
Keyword(s):  
Carbon Nanotubes ◽  
Metal Oxides ◽  
Chemical Reduction ◽  
Metal Oxide Nanoparticles ◽  
Power Input ◽  
Metal Nanoparticle ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted ◽  
Coated Metal ◽  
Size And Morphology

The study of coating carbon nanotubes with metal/oxides nanoparticles is now becoming a promising and challenging area of research. To optimize the use of carbon nanotubes in various applications, it is necessary to attach functional groups or other nanostructures to their surface. The combination of the distinctive properties of carbon nanotubes and metal/oxides is expected to be applied in field emission displays, nanoelectronic devices, novel catalysts, and polymer or ceramic reinforcement. The synthesis of these composites is still largely based on conventional techniques, such as wet impregnation followed by chemical reduction of the metal nanoparticle precursors. These techniques based on thermal heating can be time consuming and often lack control of particle size and morphology. Hence, there is interest in microwave technology recently, where using microwaves represents an alternative way of power input into chemical reactions through dielectric heating. This paper covers the synthesis and applications of carbon-nanotube-coated metal/oxides nanoparticles prepared by a microwave-assisted method. The reviewed studies show that the microwave-assisted synthesis of the composites allows processes to be completed within a shorter reaction time with uniform and well-dispersed nanoparticle formation.

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