Ion Oxidation
Mostrando 1-12 de 264 artigos, teses e dissertações.
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1. An Efficient and Recyclable Sn-Based Phosphotungstic Acid with Tunable Brønsted/Lewis Acidity for Selective Oxidation of Benzyl Alcohol
A series of metal ion (M = Sn2+, Fe3+, Ni2+, Co2+, Ag+, Cu2+) exchanged tungstophosphoric acid (H3PW12O40; TPA) catalysts with tunable Brønsted/Lewis acidity were synthesized and exploited for the oxidation of benzyl alcohol (BzOH) to benzaldehyde (BzH) using hydrogen peroxide (H2O2) as oxidant. The structure of these M-TPA composite salts was also characte
J. Braz. Chem. Soc.. Publicado em: 2021-01
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2. EVALUATION OF THE RELATIVE PROTECTION FACTOR OF ROSEMARY EXTRACT IN BIODIESEL IN THE PRESENCE OF TRANSITION METAL IONS
Biodiesel contains unsaturated methyl esters making it susceptible to oxidation reaction. Among the factors that cause oxidative instability is the contamination by transition metal ions that in small quantities catalyze the oxidation reaction. The objective of this work was to evaluate the relative protection factor of rosemary extract, in biodiesel, in the
Quím. Nova. Publicado em: 2020-09
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3. Geochemical Investigation of Tar Balls Collected in a Brazilian Beach Using Biomarkers, Ni/V, δ13C Ratios and Ultra-High Resolution FT-ICR Mass Spectrometry
Representative tar balls collected in two distinct years (2012 and 2014) in a beach along the State of Bahia, northeastern Brazil, were geochemically characterized in order to identify correlations between them and investigate potential sources. Terpanes and steranes biomarkers (detected by gas chromatography coupled to mass spectrometry, GC-MS), carbon stab
J. Braz. Chem. Soc.. Publicado em: 2020-04
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4. EFFECT OF Acidithiobacillus thiooxidans-CYSTEINE INTERACTIONS ON PYRITE BIOOXIDATION BY Acidithiobacillus ferrooxidans IN THE PRESENCE OF COAL COMPOUNDS
Abstract This study evaluated the biooxidation of pyrite contained in a Colombian coal (2.38 mm < particle size < 0.50 mm). The variables were cysteine concentration (0-600 mg/L) and culture type (pure Acidithiobacillus ferrooxidans (ATCC 23270) and a consortium of Acidithiobacillus thiooxidans (ATCC 15494) and Acidithiobacillus ferrooxidans). Pyrite oxidati
Braz. J. Chem. Eng.. Publicado em: 30/09/2019
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5. IMPROVEMENT OF AN ANALYTICAL METHOD BASED ON HPLC WITH REFRACTIVE INDEX DETECTION FOR THE ANALYSIS OF GLYCEROL OXIDATION PRODUCTS
The optimized analytical methodology described herein is based on an ion exchange column and an H3PO4 solution (pH 2.24) as the mobile phase, with a flow rate of 0.4 mL min-1 and refractive index detection (RID). On applying the methodology, it was possible to identify 7 products obtained from the oxidation of glycerol with an analysis time of 27 min. The de
Quím. Nova. Publicado em: 26/08/2019
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6. Identification of Extra Virgin Olive Oils Modified by the Addition of Soybean Oil, Using Ion Chromatography
The modification of four extra virgin olive oils from different origins with refined soybean oil (SO), in the proportions of 0, 5, 10, 20 and 30% m/m, was studied using two approaches. First, the induction period (IP) was determined by Rancimat. In the second strategy, ion chromatography was used to quantify the formic and acetic acids, in their carboxylate
J. Braz. Chem. Soc.. Publicado em: 08/04/2019
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7. Synthesis, characterization and biological activity of a gold(I) triazenide complex against chronic myeloid leukemia cells and biofilm producing microorganisms
ABSTRACT The enhancement of anti-leukemia therapy and the treatment of infections caused by multidrug-resistant pathogens are major challenges in healthcare. Although a large arsenal of drugs is available, many of these become ineffective, and as a result, the discovery of new active substances occurs. Notably, triazenes (TZCs) have been consolidated as a pr
Braz. J. Pharm. Sci.. Publicado em: 09/04/2018
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8. OXIDATION OF CYCLOHEXANOL ON PHOSPHOTUNGSTIC ACID ANION INTERCALATED LAYERED DOUBLE HYDROXIDES WITH AQUEOUS H2O2 AS OXIDANT
The layered double hydroxides (LDH) of Mg2AlNi and Mg3Al pillared by Keggin-type phosphotungstic acid anion (POM), i.e. Mg2AlNi-POM LDH and Mg3Al-POM LDH were synthesized by an ion-exchange method. The synthesized POM intercalated LDH compounds were characterized using various techniques such as FTIR, XRD, TGA and BET. The observed results show that the obta
Quím. Nova. Publicado em: 2018-01
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9. ESTUDO ATRAVÉS DE RMN DE 13C NO ESTADO SÓLIDO SOBRE A SÍNTESE DE OXIDO DE GRAFITE UTILIZANDO DIFERENTES PRECURSORES GRAFÍTICOS
The influence of the structural and microstructural characteristics of graphitic precursors on the production of graphite oxide (GO) is investigated in the present work. Six different graphitic precursors were used to produce GO following a modified Hummers method, namely: natural graphite, commercial lubricant graphite, milled graphite, graphite flakes, hig
Quím. Nova. Publicado em: 2017-10
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10. Confocal Fluorescence Microscopy and Kinetics of the Cr 3+-Chromate Ion Oxidation Equilibria at the Solid Liquid Interface
Silica-borax pearl samples impregnated with 0.17 and 0.64% Cr3+ were characterized by specific surface area measurements, UV-Vis spectroscopy, energy-dispersive X-ray fluorescence and laser-scanning confocal microscopy. Pearl stability against oxidizing conditions was tested by adding samples to an aqueous hydrogen peroxide solution. The reaction was examine
J. Braz. Chem. Soc.. Publicado em: 2017-09
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11. Anodic Oxidation of Sulfide to Sulfate: Effect of the Current Density on the Process Kinetics
The kinetics of the conversion of sulfide to sulfate by electro-oxidation, using a boron-doped diamond (BDD) electrode was studied. Different applied current densities were tested, from 10 to 60 mA cm-2. The results showed that the electrochemical conversion of sulfide to sulfate occurs in steps, via intermediate production of other sulfur species. The oxida
J. Braz. Chem. Soc.. Publicado em: 2017-04
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12. Influence of Supporting Electrolytes on RO 16 Dye Electrochemical Oxidation Using Boron Doped Diamond Electrodes
The influence of different supporting electrolytes as well as of different current densities on RO16 dye electrochemical oxidation using BDD electrodes has been systematically studied. The RO16 azo-dye electrooxidation experiments were performed at different current densities and three different supporting electrolytes: H2SO4 0.1 mol L-1, HClO4 0.1 mol L-1 a
Mat. Res.. Publicado em: 13/03/2017