scholarly journals New Trendy Magnetic C-Scorpionate Iron Catalyst and Its Performance towards Cyclohexane Oxidation

Catalysts ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. 69 ◽  
Author(s):  
Ana Ribeiro ◽  
Inês Matias ◽  
Elisabete Alegria ◽  
Ana Ferraria ◽  
Ana Botelho do Rego ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Catalytic Activity ◽  
External Magnetic Field ◽  
Microwave Irradiation ◽  
Iron Catalyst ◽  
Cyclohexane Oxidation ◽  
Butyl Hydroperoxide ◽  
Tert Butyl Hydroperoxide ◽  
Synthetic Procedure ◽  
First Time

For the first time, a magnetic C-scorpionate catalyst was prepared from the iron(II) complex [FeCl2{κ3-HC(pz)3}] (pz = pyrazol-1-yl) and ferrite, using the sustainable mechanochemical synthetic procedure. Its catalytic activity for the cyclohexane oxidation with tert-butyl hydroperoxide (TBHP) was evaluated in different conditions, namely under microwave irradiation and under the effect of an external magnetic field. The use of such magnetic conditions significantly shifted the catalyst alcohol/ketone selectivity, thus revealing a promising, easy new protocol for tuning selectivity in important catalytic processes.

scholarly journals Synthesis of cobalt nanowires in aqueous solution under an external magnetic field

2016 ◽  
Vol 7 ◽  
pp. 990-994 ◽  
Author(s):  
Xiaoyu Li ◽  
Lijuan Sun ◽  
Hu Wang ◽  
Kenan Xie ◽  
Qin Long ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Aqueous Solution ◽  
External Magnetic Field ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Chemical Reduction ◽  
Average Diameter ◽  
Firm Structure ◽  
Cobalt Nanowires ◽  
First Time

In contrast to the majority of related experiments, which are carried out in organic solvents at high temperatures and pressures, cobalt nanowires were synthesized by chemical reduction in aqueous solution with the assistance of polyvinylpyrrolidone (PVP) as surfactant under moderate conditions for the first time, while an external magnetic field of 40 mT was applied. Uniform linear cobalt nanowires with relatively smooth surfaces and firm structure were obtained and possessed an average diameter of about 100 nm with a coating layer of PVP. By comparison, the external magnetic field and PVP were proven to have a crucial influence on the morphology and the size of the synthesized cobalt nanowires. The prepared cobalt nanowires are crystalline and mainly consist of cobalt as well as a small amount of platinum. Magnetic measurements showed that the resultant cobalt nanowires were ferromagnetic at room temperature. The saturation magnetization (M s) and the coercivity (H c) were 112.00 emu/g and 352.87 Oe, respectively.

scholarly journals Low-Offset In-Plane Sensitive Hall Arrangement

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 713
Author(s):  
Siya Lozanova ◽  
Ivan Kolev ◽  
Avgust Ivanov ◽  
Chavdar Roumenin
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Output Voltage ◽  
Cross Coupling ◽  
The Novel ◽  
Temperature Drift ◽  
Low Offset ◽  
First Time ◽  
Single Configuration ◽  
Hall Elements

A novel in-plane sensitive Hall arrangement consisting of two identical n-Si three-contact (3C) elements and realized in a common technological process, is presented. In the solution, the minimization of the offset and its temperature drift is achieved by cross-coupling of the outer device contacts. This terminals’ connection provides equalizing currents between the two substrates which strongly compensate the inevitable difference in the electrical conditions in the two parts of the arrangement. As a result, the residual offset of both integrated Hall elements at the output Vout(0) and its temperature drift are strongly minimized. The residual offset is about 160 times smaller than the single-configuration one. The obtained output voltage-to-residual offset ratio at sensitivity of SRI ≈ 98 V/AT is very promising, reaching 6 × 103 at temperature T = 40 °C and induction 1 T. As a result, increased metrological accuracy for numerous applications is achieved. For a first time through the novel arrangement a suppression of sensitivity in the presence of external magnetic field could be achieved in order to obtain permanent offset information. This is one of the key results in the Hall device investigation.

scholarly journals Low-Temperature Behavior of the Specific Heat for an N-Spin Ferromagnetic Material in an External Magnetic Field

2018 ◽  
Vol 9 (3) ◽  
pp. 36
Author(s):  
Seung-Yeon Kim
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Low Temperature ◽  
Specific Heat ◽  
Ferromagnetic Material ◽  
Low Energy ◽  
Temperature Behavior ◽  
Energy Structure ◽  
Schottky Anomaly ◽  
First Time

<p>A ferromagnetic material in the absence of an external magnetic field shows the peak of its specific heat in low temperature, called the Schottky anomaly, which is vital in understanding the low-energy structure of a given material. A general formula for the low-temperature behavior of the specific heat of an N-spin ferromagnetic material in an external magnetic field (the generalized Schottky anomaly) is obtained for the first time. Also, as a representative example of ferromagnetic materials in an external magnetic field, the low-temperature behavior of the specific heat for the Ising ferromagnet is studied.</p>

Influence of tungsten compounds on reaction of 1-octene epoxidation by tert-butyl hydroperoxide and hydroperoxide decomposition

2021 ◽  
Vol 4 (2) ◽  
pp. 23-27
Author(s):  
O. I. Makota ◽  
◽  
L. P. Oliynyk ◽  
Z. М. Komarenska ◽  
◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Tungsten Carbide ◽  
Decomposition Reaction ◽  
Butyl Hydroperoxide ◽  
Tert Butyl ◽  
Hydroperoxide Decomposition ◽  
Tert Butyl Hydroperoxide ◽  
Epoxidation Reaction ◽  
Tungsten Boride

Catalytic ability of tungsten compounds in the reaction of hydroperoxide epoxidation of 1- octene and tert-butyl hydroperoxide decomposition was investigated. It is shown that the nature of ligand has significant effect on the catalytic activity of tungsten compounds in these reactions. It is established that boride and silicide of tungsten are the best choice for epoxidation reaction, whereas tungsten carbide exhibits poor activity. Tungsten boride is also the most active in the hydroxide decomposition reaction.

Shape-dependent catalytic activity of Fe3O4 nanostructures under the influence of an external magnetic field for multicomponent reactions in aqueous media

RSC Advances ◽  
2015 ◽  
Vol 5 (90) ◽  
pp. 74091-74101 ◽  
Author(s):  
E. Rafiee ◽  
M. Joshaghani ◽  
P. Ghaderi-Shekhi Abadi
Keyword(s):  
Magnetic Field ◽  
Catalytic Activity ◽  
External Magnetic Field ◽  
Multicomponent Reactions ◽  
Aqueous Media ◽  
Imidazole Derivatives

Fe3O4 nanostructures were synthesized under external magnetic field, shown shape-dependent catalytic activity for the synthesis of imidazole derivatives in water.

Detection of intermediates and isolation of hydroquinone monoacetate in the Dakin oxidation of p-hydroxyacetophenone

1978 ◽  
Vol 56 (20) ◽  
pp. 2646-2649 ◽  
Author(s):  
Martin B. Hocking ◽  
Ming Ko ◽  
Trevor A. Smyth
Keyword(s):  
Hydrogen Peroxide ◽  
Peracetic Acid ◽  
Isolation Procedure ◽  
Peroxide Oxidation ◽  
Aqueous Hydrogen Peroxide ◽  
Butyl Hydroperoxide ◽  
Tert Butyl ◽  
Tert Butyl Hydroperoxide ◽  
Hydrogen Peroxide Oxidation ◽  
First Time

Oxidation of o-, m-, and p-hydroxyacetophenone with peracetic acid or tert-butyl hydroperoxide, oxidants relatively readily monitored by nmr, failed to generate isolable intermediates though an intermediate was detected for the p-ketone. Attempted oxidation of a number of related ketones under Dakin conditions failed either to react, or to generate a detectable intermediate. However, with delicate adjustment of pH and careful timing of the isolation procedure, hydroquinone monoacetate has for the first time been successfully isolated from an alkaline aqueous hydrogen peroxide oxidation (Dakin oxidation) of p-hydroxyacetophenone.

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