scholarly journals Multinuclear Magnetic Resonance Study on Aluminium Sec-butoxide Chelated with Ethyl Acetoacetate in Various Amounts

2019 ◽  
Vol 92 (1) ◽  
pp. 17-28 ◽  
Author(s):  
Stanislav Kurajica ◽  
Gregor Mali ◽  
Vilko Mandić ◽  
Iva Minga
Keyword(s):  
Ethyl Acetoacetate ◽  
Sol Gel ◽  
Gain Control ◽  
Spectroscopic Techniques ◽  
27Al Nmr ◽  
One Dimensional ◽  
Sol Gel Process ◽  
Rapid Hydrolysis ◽  
First Time

Reactive aluminum alkoxide (ASB, aluminium sec-butoxide) was chelated using β-diketone (EAA, ethyl acetoacetate) in order to gain control over rapid hydrolysis in the course of the sol-gel process. Derived chelates were analysed using several NMR spectroscopic techniques: one-dimensional 1H, 13C, 27Al NMR and two-dimensional COSY, HSQC and DOSY. The NMR analysis enabled identification of the formed chelate species, as well as determination of their quantitative relationships. Several complexation products were observed: tris-chelated monomer, Al(EAA)3, bis-chelated dimmer, Al2(OnBu)4(EAA) 2, tris-chelated dimmer, Al2(OnBu)3(EAA)3, tetra-chelated dimmer, Al2(OnBu)2(EAA)4, and monochelated trimer, Al3(OnBu)8(EAA). Of the formed oligomer compounds, this is the first evidence of Al2(OR)3L3 in any alkoxide and β-ketoester or β-diketone combination. Aluminium sec-butoxide and ethyl acetoacetate complexes Al2(OnBu)4(EAA) 2 and Al2(OnBu)2(EAA)4 were also observed for the first time. With the increase of the EAA/ASB ratio the coordination of aluminium shifts towards six, whereas above the EAA/ASB ratio of 2.5 solely six-coordinated aluminium exists.

scholarly journals A Brief Review on the Use of Chelation Agents in Sol-gel Synthesis with Emphasis on β-Diketones and β-Ketoesters

2019 ◽  
Vol 33 (3) ◽  
pp. 295-301 ◽  
Author(s):  
Sanislav Kurajica
Keyword(s):  
Ethyl Acetoacetate ◽  
Sol Gel ◽  
Chelating Agent ◽  
Short Review ◽  
Metal Alkoxides ◽  
Structure And Properties ◽  
Gel Structure ◽  
Sol Gel Process ◽  
Rapid Hydrolysis ◽  
Sol Gel Synthesis

Metal alkoxides are the most commonly used sol-gel process precursors. Most<br /> alkoxides show excessive reactivity towards water. That leads to rapid hydrolysis, metal<br /> hydroxide formation, and immediate precipitation. The reactivity of alkoxides can be<br /> reduced by modification with chelation agents. Chelation influences the gelation process,<br /> which is reflected in gel structure and properties of the final material. In this short review,<br /> the chelation process, the oligomerization phenomena, and the influence of the chelating agent on the gel structure are discussed. Peculiarities of the use of FTIR and NMR, as methods particularly suitable for the investigation of chelation process, are described taking ethyl acetoacetate as an example.

Influence of Li2+ Doping on the Structural and Optical Properties of CaO Synthesized by Sol–Gel Process

2019 ◽  
Vol 07 (01n02) ◽  
pp. 1950002
Author(s):  
Nadir Lalou ◽  
Ahmed Kadari
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Sol Gel ◽  
Calcium Nitrate ◽  
Lithium Nitrate ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Sol Gel Process ◽  
Ft Ir ◽  
First Time

This work proposes the synthesis of nanocrystalline calcium oxide (CaO) pure and doped with different concentrations of lithium (Li[Formula: see text]) ions by sol–gel process. Calcium nitrate (Ca(NO[Formula: see text]4H2O; 99.99%) and lithium nitrate (LiNO3; 99.99%) were used as precursors. The synthesized powders were characterized by several techniques such as: UV-Vis transmission spectroscopy, Fourier Transform Infra-red spectroscopy (FT-IR) and X-ray diffraction (XRD). The main objective of this paper is to study the influence of lithium (Li[Formula: see text] ratio) on the structural and optical properties of synthesized powders. The band gap values decreased with the increasing of Li[Formula: see text] ions in CaO lattice; the slight change in the band gap was directly related to the energy transfer between the CaO excited states and the 2s levels of Li[Formula: see text] ions. The influence of Li[Formula: see text] doping on the physical properties of CaO nanocrystalline will be studied for the first time in this work; no literature has previously published this kind of impurities.

Porous graphene to encapsulate Na6.24Fe4.88(P2O7)4 as composite cathode materials for Na-ion batteries

2015 ◽  
Vol 51 (66) ◽  
pp. 13120-13122 ◽  
Author(s):  
Yubin Niu ◽  
Maowen Xu ◽  
Shu-Juan Bao ◽  
Chang Ming Li
Keyword(s):  
Cathode Materials ◽  
Sol Gel ◽  
Composite Cathode ◽  
Porous Graphene ◽  
Graphene Composite ◽  
Sol Gel Process ◽  
First Time

Na6.24Fe4.88(P2O7)4@porous graphene composite is fabricated as a cathode of Na-ion batteries for the first time by a hydrothermally assisted sol–gel process.

scholarly journals Formation of nanoscopic CaF2via a fluorolytic sol–gel process for antireflective coatings

2015 ◽  
Vol 3 (8) ◽  
pp. 1716-1723 ◽  
Author(s):  
Alexander Rehmer ◽  
Kerstin Scheurell ◽  
Erhard Kemnitz
Keyword(s):  
Sol Gel ◽  
Nano Particles ◽  
Antireflective Coatings ◽  
Sol Gel Process ◽  
Sol Gel Synthesis ◽  
First Time

For the first time transparent antireflective CaF2-coatings were prepared from clear CaF2-sols obtained via the fluorolytic sol–gel synthesis and containing homo-dispersed CaF2 nano-particles.

Voltammetric determination of aluminum(III) using a reagentless sensor fabricated by sol–gel process

2004 ◽  
Vol 99 (2-3) ◽  
pp. 468-473 ◽  
Author(s):  
Junwei Di ◽  
Shuping Bi ◽  
Tianyu Yang ◽  
Ming Zhang
Keyword(s):  
Sol Gel ◽  
Voltammetric Determination ◽  
Sol Gel Process

PRODUCTION AND CHARACTERIZATION OF ALUMINA NANOPARTICLES FROM GIRO CLAY VIA ACID LEACHING WITH SOL GEL METHOD

2021 ◽  
Vol 15 (1) ◽  
pp. 1-10
Author(s):  
S. O. Balogun ◽  
S. A. Yaro ◽  
M. Abdulwahab ◽  
A. Kasim
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Acid Leaching ◽  
Alumina Nanoparticles ◽  
High Alumina ◽  
Spectroscopic Techniques ◽  
Gel Method ◽  
Sol Gel Method ◽  
Sol Gel Process ◽  
Ph Range

Alumina nanoparticles were synthesized from locally available high alumina clay, obtained from Giro in Kabbi State, through acid leaching with sol-gel method. The clay was leached with hydrofluoric acid and the aluminous solution produced was used as precursor to synthesis nanoparticles through sol gel process. The composition and structure of the clay and the particles produced were characterized using Fourier Transform Infrared (FTIR), X-ray diffraction and fluorescence Spectroscopic techniques, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). From the analyses, the clay sample was observed to be high in alumina and predominantly Kaolinitic in nature. During the sol-gel process, effective flocculation was obtained at slightly alkaline pH range (7.6 to 8.0) and a relative moderate temperature of 80oC. The result also shows that the aging time of the gel affected the size of the particles produced during the process, and the particles are mainly nano-alumina.

Lanthanum zirconate: A single buffer layer processed by solution deposition for coated conductor fabrication

2002 ◽  
Vol 17 (9) ◽  
pp. 2181-2184 ◽  
Author(s):  
S. Sathyamurthy ◽  
M. Paranthaman ◽  
H-Y. Zhai ◽  
H. M. Christen ◽  
P. P. Martin ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Low Cost ◽  
Sol Gel ◽  
Single Layer ◽  
Coated Conductors ◽  
Buffer Layers ◽  
Solution Deposition ◽  
Sol Gel Process ◽  
Current Densities ◽  
First Time

A single layer of La2Zr2O7 (LZO), deposited on textured Ni and Ni–1.7% Fe–3% W (Ni–W) tapes by a low-cost sol-gel process, is used as buffer layer for the growth of YBa2Cu3O7−δ (YBCO) coated conductors. It is shown for the first time that such single buffer layers can be used for the deposition of YBCO yielding critical current densities (Jc) that are comparable to those typically obtained using CeO2/YSZ/Y2O2 trilayers on identical substrates, i.e., in excess of 1 MA/cm2 at 77 K and self-field. The properties of the YBCO films and the dependence of Jc on thickness of the LZO layer are investigated.

scholarly journals Synthesis and characterization of nanocrystalline PZT powders: From sol to dense ceramics

2016 ◽  
Vol 10 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Ali Mirzaei ◽  
Maryam Bonyani ◽  
Shahab Torkian
Keyword(s):  
Electron Microscopy ◽  
Lead Zirconate Titanate ◽  
Sol Gel ◽  
Microstructural Characterization ◽  
Lead Zirconate ◽  
Nanocrystalline Powders ◽  
Spectroscopic Techniques ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Dta Analysis

In this study ferroelectric lead zirconate titanate PZT (0.523/0.477) nanocrystalline powders have been successfully synthesized by an alkoxide based sol-gel process. Crystallinity of the prepared ceramic powders was studied using X-ray diffractometer. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies were performed to study morphology of the calcined powders. EDX analysis was employed to demonstrate purity of the synthesized powders. Surface nature of the powders was studied by using FTIR technique. TGA/DTA analysis was employed to study thermal behaviour of powders. Spectroscopic techniques (FTIR and XRD) results indicated that the as-dried amorphous powders can be completely crystallized at 600?C. In order to investigate the densification behaviour of the calcined powders, the crystalline PZT powders were pelletized into discs and sintered at various temperatures from 900?C to 1150?C, with a heating rate of 10?C/min and holding time of 2 h to find the optimum combination of temperature and time to produce high density ceramics. Microstructural characterization was conducted on the fractured surface of the samples using SEM. It was found that the PZT ceramics calcined at 600?C for 4 h then sintered at 1050?C for 2 h had maximal density (98% of the theoretically density).

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