28/6/2012
Saiu o JBCS número 6 - Volume 23
High School Chemistry Teaching: How to Improve it?
On its 34th anniversary, the Brazilian Chemical Society (BCS) reaffirms itself as one of the most prominent scientific societies in Brazil. Its importance for the high standard reached by the Brazilian university system, since its foundation in 1977, can be measured by the several Presidents an Vice-Presidents of Universities from all over the country that have been part of the BCS Annual Meetings.
(Read more at Editorial)
Table of Contents with Graphical Abstracts
Surface Properties of Oxidized and Aminated Multi-Walled Carbon Nanotubes |
Wellington M. Silva, Hélio Ribeiro, Luciana M. Seara, Hállen D. R. Calado, André S. Ferlauto,
Roberto M. Paniago, Cristiano F. Leite and Glaura G. Silva
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Functionalization or chemical modification of carbon nanotubes through the covalent attachment of atoms or molecules to the surface has been used to introduce chemical specificity allowing their processability in different environments. Evaluating the functionalization distribution of groups on the carbon nanotube surface is an important task. It can be achieved by monitoring the phase shift with electric force microscopy (EFM). The images obtained give qualitative information of the local charge distribution through contrast in areas where the conductivity varies.. |
The cover picture shows, with different color palette, EFM images of neat and functionalized carbon nanotubes. Details are discussed in the Article Surface Properties of Oxidized and Aminated Multi-Walled Carbon Nanotubes by Silva et al. on page 1078. |
>> Editorial(366 KB)
High School Chemistry Teaching: How to Improve it?
Angelo C. Pinto |
| J. Braz. Chem. Soc. 2012, 23, 985. |
The Impressive Chemistry, Applications and Features of Ionic Liquids: Properties, Catalysis & Catalysts and Trends |
| Brenno A. D. Neto and John Spencer |
| J. Braz. Chem. Soc. 2012, 23, 987. |
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| The chemistry of ionic liquids is impressive. No doubt! In this article it is overviewed some contributions to the development of catalysis and catalysts in ionic liquids, especially those with imidazolium-based derivatives. Due to the importance of ionic liquids, some physicochemical properties of interest and their supramolecular organization are also described |
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Published online: May 22, 2012 |
Chemical Modification of Polyaniline by N-Grafting of Polystyrenic Chains Synthesized via Nitroxide-Mediated Polymerization |
| Maryam Hatamzadeh, Ali Mahyar and Mehdi Jaymand |
| J. Braz. Chem. Soc. 2012, 23, 1008. |
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| Conductive N-substituted polyaniline was synthesized by incorporation of brominated polystyrenic chains onto emeraldine form of polyaniline. The obtained terpolymer was characterized using FTIR, DSC, TGA, UV-Vis and cyclic voltammetry |
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Published online: April 24, 2012 |
Kinetic Modeling of the Alkaline Decomposition of Potassium Arsenojarosite |
| Mizraim U. Flores, Francisco Patiño, Iván A. Reyes, Isauro Rivera, Martín Reyes and Julio C. Juárez |
| J. Braz. Chem. Soc. 2012, 23, 1018. |
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| The kinetic model that describes the alkaline decomposition of potassium arsenojarosite in NaOH and Ca(OH)2 media was obtained and verified |
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Published online: April 26, 2012 |
The Influence of the Amount and Impregnation Sequence of Potassium on the Catalytic Performance of VOx /Al2O3 for the Non-Oxidative Dehydrogenation of n-Butane |
| María A. Volpe and Elba A. García |
| J. Braz. Chem. Soc. 2012, 23, 1024. |
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| This figure shows TPR (temperature programmed reduction) profiles of fresh and regenerated K-promoted vanadium-alumina catalysts. The differences observed in these TPR patterns confirm that the deactivation of these catalysts may be related with irreversible structural changes in the vanadium oxide speciation |
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Published online: May 3, 2012 |
Dispersive Liquid-Liquid Microextraction Procedure for the Determination of Palladium by Flame Atomic Absorption Spectroscopy |
| Serife Sacmaci, Senol Kartal and Sevilay Dural |
| J. Braz. Chem. Soc. 2012, 23, 1033. |
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| The important steps of dispersive liquid-liquid microextraction procedure for the determination of palladium(II) using 2,2'-furyldioxime. A new dispersive liquid-liquid microextraction system was developed for the determination of Pd(II) in catalytic converter, anode slime, road sediment and water samples. The compound 2,2'-furyldioxime as a complexing agent was firstly used in the determination of Pd(II) by flame atomic absorptin spectrometry using dispersive liquid-liquid microextraction procedure |
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Published online: May 3, 2012 |
Chemical Composition Similarity between Essential Oils Isolated from Male and Female Specimens of Each Five Baccharis Species |
| Michele A. Besten, Vanessa C. G. Jasinski, Ângela de G. L. C. Costa, Domingos S. Nunes, Sávio L. Sens, Alberto Wisniewski Jr., Edesio L. Simionatto, Dilamara Riva,Juliana B. Dalmarco and Daniel Granato |
| J. Braz. Chem. Soc. 2012, 23, 1041. |
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| The analytical data presented in this study demonstrate that there may be a high degree of similarity between the compositions of essential oils from male and female specimens of Baccharis species |
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Published online: May 3, 2012 |
A Validated Chiral LC Method for the Enantiomeric Separation of Repaglinide on Immobilized Amylose Based Stationary Phase |
| Kiran Patil, Vipul Rane, Ravindra Yeole and Devanand Shinde |
| J. Braz. Chem. Soc. 2012, 23, 1048. |
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| Enatiomeric resolution of repaglinide achieved on Chiralpak IA column using n-hexane:ethanol:TFA (80:20:0.2, v/v/v) |
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Published online: May 8, 2012 |
1H HRMAS NMR Spectroscopy and Chemometrics for Evaluation of Metabolic Changes in Citrus sinensis Caused by Xanthomonas axonopodis pv. citri |
| Lorena M. A. Silva, Elenilson G. Alves Filho, Rafael Choze, Luciano M. Lião and Glaucia B. Alcantara |
| J. Braz. Chem. Soc. 2012, 23, 1054. |
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Orange tree leaves and orange peels attacked by citrus canker were analyzed by HRMAS NMR and chemometrics. Changes in metabolic profile have highlighted biochemical responses |
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Published online: May 8, 2012 |
An Efficient Synthesis of D-Galactose-Based Multivalent Neoglycoconjugates |
| Saulo F. de Andrade, Rute C. Figueiredo, José D. de Souza Filho and Ricardo J. Alves |
| J. Braz. Chem. Soc. 2012, 23, 1062. |
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| An efficient synthesis of five D-galactose-based multivalent neoglycoconjugates from peracetylated D-galactose is reported. Glycodendrimers were obtained in few steps using cheap reactants in 44-55% overall yields |
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Published online: May 10, 2012 |
Fabrication, Characterization and Analytical Performance of the Hydroxylamine Sensor Based on an Oracet Blue Multi-Walled Carbon Nanotubes Film Deposited on an Electrode Surface |
| Hamid R. Zare and Navid Nasirizadeh |
| J. Braz. Chem. Soc. 2012, 23, 1070. |
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| Cyclic voltammograms of a glassy carbon electrode modified with oracet blue and multi-walled carbon nanotubes (OBMWCNT-GCE) in a 0.1 mol L-1 phosphate buffer solution (pH 7.0) at scan rate 20 mV s-1 in (a) the absence and (b) the presence of 0.50 mmol L-1 hydroxylamine. (d), (e) and (f) as (b) for OBMGCE, MWCNT-GCE and activated GCE, respectively. (c) as (a) for OBMGCE |
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Published online: May 15, 2012 |
Surface Properties of Oxidized and Aminated Multi-Walled Carbon Nanotubes |
Wellington M. Silva, Hélio Ribeiro, Luciana M. Seara, Hállen D. R. Calado, André S. Ferlauto,
Roberto M. Paniago, Cristiano F. Leite and Glaura G. Silva |
| J. Braz. Chem. Soc. 2012, 23, 1078. cover article |
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| In order to characterize the chemical modifications that were introduced onto the surface of multi-walled carbon nanotubes, studies involving Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, transmission electron microscopy and electric force microscopy were performed |
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Published online: May 15, 2012 |
ESI-MS Study of Speciation in Hydrolyzed Aluminum Chloride Solutions |
| Mirjana Cvijovic, Vesna Kilibarda, Milena Jelikic-Stankov, Ivan Lazarevic, Ivan Jakovljevic, Ljubinka Joksovic and Predrag Durdevic |
| J. Braz. Chem. Soc. 2012, 23, 1087. |
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| In a chloride-containing medium, aluminum ions form a variety of low and high molecular weight hydrolytic complexes with +1 and +2 charge at pH values lower than 6.0. The complexes may contain coordinated water molecules and chloride ions. The best correspondence between 27Al nuclear magnetic resonance (NMR), potentiometric and mass spectral data is achieved at lower fragmentation voltage and with quadrupole detection |
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Published online: May 15, 2012 |
Determination of the Hydrophobic Fraction of Ca, Fe, Mg and Zn in Dark Color Honeys using Solid Phase Extraction and Flame Atomic Absorption Spectrometry |
| Pawel Pohl, Helena Stecka, Krzysztof Greda and Piotr Jamroz |
| J. Braz. Chem. Soc. 2012, 23, 1098. |
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| Silica gel with bonded phenyl active groups was used to separate the hydrophobic fraction of Ca, Fe, Mg and Zn in dark honeys. Fe was found to be associated with this fraction to the highest degree (7-43% of its total). A strong positive correlation was established between the concentration of Fe in the hydrophobic fraction and the optical density of dark honeys |
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Published online: May 17, 2012 |
Ab Initio Correlated All Electron Dirac-Fock Calculations for Eka-Francium Fluoride (E119F) |
| Patrícia S. Miranda, Anna Paula S. Mendes, Jose S. Gomes, Claudio N. Alves, Aguinaldo R. de Souza, Julio R. Sambrano, Ricardo Gargano and Luiz Guilherme M. de Macedo |
| J. Braz. Chem. Soc. 2012, 23, 1104. |
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| Bader volumes obtained with contour density of 0.001 a.u. at 4-component Dirac-Fock level suggest that eka-francium fluoride (top molecule, E119 in pink color) should be less ionic than lighter alkaline fluoride homologue such as KF (K in green), in contrast to the common chemical belief based on periodic trends - it would be expected the most ionic bond possible. This result should be understood as a consequence of relativistic effects |
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Published online: May 22, 2012 |
Purification of a Synthetic Pterocarpanquinone by Countercurrent Chromatography |
| Fernanda das Neves Costa, Alcides José M. da Silva, Chaquip Daher Netto, Jorge L. de Oliveira Domingos, Paulo Roberto R. Costa and Gilda G. Leitão |
| J. Braz. Chem. Soc. 2012, 23, 1114. |
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| Countercurrent chromatography (CCC) was employed as a useful, fast and economic alternative to conventional chromatography techniques for the purification of a synthetic pterocarpanquinone, LQB-118 |
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Published online: May 24, 2012 |
Efficient Synthesis of Functionalized 1,2,3-Triazoles by Catalyst-Free 1,3-Dipolar Cycloaddition of Nitroalkenes with Sodium Azide |
| Ting Wang, Xiao-Chun Hu, Xu-Jiao Huang, Xin-Sheng Li and Jian-Wu Xie |
| J. Braz. Chem. Soc. 2012, 23, 1119. |
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| A simple and efficient protocol has been developed for the synthesis of 1,2,3-triazole derivatives by catalyst-free 1,3-dipolar cycloaddition of nitroalkenes with sodium azide under mild conditions. The reaction's scope proved to be quite broad and 1,2,3-triazole derivatives were obtained in good yields |
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Published online: May 24, 2012 |
Electrochemical Detection of Pb and Cd in Paper-Based Microfluidic Devices |
| Jianjun Shi, Fan Tang, Honglong Xing, Huxiang Zheng, Lianhua Bi and Wei Wang |
| J. Braz. Chem. Soc. 2012, 23, 1124. |
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Filter paper strip is combined with screen-printed carbon electrodes (SPCE) to assemble a microfluidic device for detecting Pb(II) and Cd(II) in aqueous samples. The portable microfluidic devices are demonstrated for direct quantification of Pb(II) and Cd(II) in aqueous samples without pretreatment of contaminated samples |
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Published online: May 24, 2012 |
Electrochemical Reduction of the Mycotoxin Citrinin at Bare and Modified with Multi-Walled Carbon Nanotubes Glassy Carbon Electrodes in a Non-Aqueous Reaction Medium |
Vanessa G. L. Zachetti, Adrian M. Granero, Sebastian N. Robledo, María A. Zon,
Carlos A. DaRocha Rosa and Héctor Fernández |
| J. Braz. Chem. Soc. 2012, 23, 1131. |
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| In this study, the electrochemical reduction mechanism of citrinin (CITH) mycotoxin in a non-aqueous reaction medium was investigated. (CITH)2H2 is the dimeric product obtained from the Michael-type nucleophilic addition reaction of CITH2- carbanion with another CITH molecule |
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Published online: May 29, 2012 |
High-Time Resolution Measurements of Black Carbon Particles in the Exhaust Emissions of a Diesel Engine during Acceleration, Deceleration and Cruise Conditions |
| Antonio H. Miguel and Anthony D. A. Hansen |
| J. Braz. Chem. Soc. 2012, 23, 1140. |
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| We used an Aethalometer® to measure BC concentrations with 5 s time resolution in the exhaust of a 1995 Dodge RAM 2500 diesel pick-up truck, equipped with an oxidation catalyst, using a chassis dynamometer during the acceleration, deceleration, and cruise modes of the hot start of the MEC01 test cycle (version 7.0) |
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Published online: June 5, 2012 |
PtSnIr/C Anode Electrocatalysts: Promoting Effect in Direct Ethanol Fuel Cells |
| Júlio C. M. Silva, Rodrigo F. B. De Souza, Mayara A. Romano, Melina D’Villa-Silva, Marcelo L. Calegaro, Peter Hammer, Almir O. Neto and Mauro C. Santos |
| J. Braz. Chem. Soc. 2012, 23, 1146. |
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| The activities of PtSnIr/C and PtSn/C E-tek electrocatalysts were evaluated in a direct ethanol fuel cell (DEFC) and similar performance was obtained using PtSnIr/C, with half content of platinum. In situ Fourier transform infrared (FTIR) analysis revealed acetic acid as main product generated from ethanol oxidation on PtSnIr/C |
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Published online: June 5, 2012 |
Determination of Carbamates in Beverages by Liquid-Liquid Extraction with Low Temperature Partitioning and Liquid Chromatography |
Simone M. Goulart, Renata D. Alves, Washington X. de Paula, José Humberto de Queiroz,
Antônio A. Neves and Maria Eliana L. R. de Queiroz |
| J. Braz. Chem. Soc. 2012, 23, 1154. |
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| Liquid-liquid extraction with low temperature partitioning was proposed to determine the carbamates pesticides, aldicarb, carbofuran and carbaryl, in grape juice and chocolate milk beverages. The method was quick, cheap and may be easily implemented for routine analysis |
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Published online: June 5, 2012 |
Determination of Copper in Human Hair and Tea Samples after Dispersive Liquid.Liquid Microextraction Based on Solidification of Floating Organic Drop (DLLME-SFO) |
| Soleiman Bahar and Razieh Zakerian |
| J. Braz. Chem. Soc. 2012, 23, 1166. |
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| The Figure shows efficiency of DLLME-SFO technique for the extraction of the copper ion with the oxine ligand and using different extraction (1-dodecanol, 1-undecanol) and disperser (methanol, ethanol, acetone, acetonitrile) solvents |
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Published online: June 6, 2012 |
Oncocalyxone A: Electrochemical, Spectroscopic Investigation and Studies of Its Interaction with DNA, Nucleobases and N-Acetylcysteine |
| Cicero de O. Costa, Erivaldo de O. Costa, Fabrícia da R. Ferreira, Luciana da S. Viana, Leonardo V. da Silva, Francisco de A. dos Santos Silva, Fabiane C. de Abreu, Isis M. Figueiredo, Waldomiro Pinho Jr., Edson de S. Bento, Telma L. G. Lemos, Otília D. L. Pessoa, Benjamin Aguilera-Venegas, Ester Norambuena, Claudio Olea-Azar and Marília O. F. Goulart |
| J. Braz. Chem. Soc. 2012, 23, 1174. |
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| Oncocalyxone A has been shown to be cytotoxic to human tumor cells and DNA reactive. Electrochemical-electron spin resonance revealed the stability of its semiquinone. Experiments with nucleobases and ssDNA (single-stranded DNA) proved the DNA interaction. Nuclear magnetic resonance (NMR) experiments with N-acetylcysteine evidenced its Michael acceptor nature |
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Published online: June 6, 2012 |
Preparation of Ordered Sulfonated Mesoporous Polymer (OMP-TsOH) from p-Toluenesulfonic Acid and Application in Esterification Reaction of Fatty Acids |
| Arash Shokrolahi, Abbas Zali, Hamid Reza Pouretedal and Ali Mousaviazar |
| J. Braz. Chem. Soc. 2012, 23, 1186. |
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| Sulfonated ordered mesoporous polymers were prepared by co-mixing p-formaldehyde, p-toluenesulfonic acid (p-TsOH), sulfuric acid and mesoporous silica (SBA-15 or MCM-48) as a template. The prepared materials were applied as catalyst in oleic acid esterification with methanol |
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Published online:June 6, 2012 |
Fluoride Determination in Carbon Nanotubes by Ion Selective Electrode |
| Fabiane G. Antes, Juliana S. F. Pereira, Laurien C. Spadoa, Edson I. Muller, Erico M. M. Flores and Valderi L. Dressler |
| J. Braz. Chem. Soc. 2012, 23, 1193. |
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| Fluoride determination in single and multi-walled carbon nanotubes was performed by ion-selective electrode after pyrohydrolysis. It was possible to digest up to 1 g of sample and to achieve low LOD |
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Published online: April 26, 2012 |
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