JBCS

8:07, Thu Apr 27

Open Access/APCs

vol. 23, No. 6, 2012, p. 985-1198

 

High School Chemistry Teaching: How to Improve it?

On its 35th 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 and Vice-Presidents of Universities from all over the country that have been part of the BCS Boards and Advisory Councils or who have been Regional Secretaries of the BCS. A number of these leaders were forged in the memorable general assemblies of the BCS Annual Meetings.

(Read more at Editorial)


Cover Article
J. Braz. Chem. Soc. 2012, 23(6), 1078-1086

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; Glaura G. Silva

How to cite this article

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..

http://dx.doi.org/10.1590/S0103-50532012000600012

Published online: May 15, 2012

Editorial J. Braz. Chem. Soc. 2012, 23(6), 985-986

High school chemistry teaching: how to improve it?

Angelo C. Pinto

How to cite this article

 

http://dx.doi.org/10.1590/S0103-50532012000600001


Account J. Braz. Chem. Soc. 2012, 23(6), 987-1007

The impressive chemistry, applications and features of ionic liquids: properties, catalysis & catalysts and trends

Brenno A. D. Neto; John Spencer

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600002

Published online: May 22, 2012

Articles J. Braz. Chem. Soc. 2012, 23(6), 1008-1017

Chemical modification of polyaniline by N-grafting of polystyrenic chains synthesized via nitroxide-mediated polymerization

Maryam Hatamzadeh; Ali Mahyar; Mehdi Jaymand

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600003


J. Braz. Chem. Soc. 2012, 23(6), 1023-1018

Kinetic modeling of the alkaline decomposition of potassium arsenojarosite

Mizraim U. Flores; Francisco Patiño; Iván A. Reyes; Isauro Rivera; Martín Reyes; Julio C. Jußrez

How to cite this article

 

The kinetic model that describes the alkaline decomposition of potassium arsenojarosite in NaOH and Ca(OH)2 media was obtained and verified

http://dx.doi.org/10.1590/S0103-50532012000600004

Published online: April 26, 2012

J. Braz. Chem. Soc. 2012, 23(6), 1024-1032

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; Elba A. García

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600005

Published online: May 3, 2012

J. Braz. Chem. Soc. 2012, 23(6), 1033-1040

Dispersive liquid-liquid microextraction procedure for the determination of palladium by flame atomic absorption spectroscopy

Şerife Saçmacl; Şenol Kartal; Sevilay Dural

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600006

Published online: May 3, 2012

J. Braz. Chem. Soc. 2012, 23(6), 1041-1047

Chemical composition similarity between the 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; Daniel Granato

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600007

Published online: May 3, 2012


J. Braz. Chem. Soc. 2012, 23(6), 1048-1053

A validated chiral LC method for the enantiomeric separation of repaglinide on immobilized amylose based stationary phase

Kiran Patil; Vipul Rane; Ravindra Yeole; Devanand Shinde

How to cite this article

 

Enatiomeric resolution of repaglinide achieved on Chiralpak IA column using n-hexane:ethanol:TFA (80:20:0.2, v/v/v)

http://dx.doi.org/10.1590/S0103-50532012000600008

Published online: May 8, 2012

J. Braz. Chem. Soc. 2012, 23(6), 1054-1061

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; Glaucia B. Alcantara

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600009

Published online: May 8, 2012


J. Braz. Chem. Soc. 2012, 23(6), 1062-1069

An efficient synthesis of D-galactose-based multivalent neoglycoconjugates

Saulo F. de Andrade; Rute C. Figueiredo; José D. de Souza Filho; Ricardo J. Alves

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600010



J. Braz. Chem. Soc. 2012, 23(6), 1070-1077

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; Navid Nasirizadeh

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600011

Published online: May 15, 2012

J. Braz. Chem. Soc. 2012, 23(6), 1078-1086

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; Glaura G. Silva

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600012

Published online: May 15, 2012


J. Braz. Chem. Soc. 2012, 23(6), 1087-1097

ESI-MS study of speciation in hydrolyzed aluminum chloride solutions

Mirjana Cvijovic; Vesna Kilibarda; Milena Jelikic-Stankov; Ivan Lazarevic; Ivan Jakovljevic; Ljubinka Joksovic; Predrag Durdevic

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600013


J. Braz. Chem. Soc. 2012, 23(6), 1098-1103

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; Piotr Jamroz

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600014

Published online: May 17, 2012

J. Braz. Chem. Soc. 2012, 23(6), 1104-1113

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; Luiz Guilherme M. de Macedo

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600015

Published online: May 22, 2012

J. Braz. Chem. Soc. 2012, 23(6), 1114-1118

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; Gilda G. Leitão

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600016

Published online: May 24, 2012

J. Braz. Chem. Soc. 2012, 23(6), 1119-1123

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; Jian-Wu Xie

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600017

Published online: May 24, 2012


J. Braz. Chem. Soc. 2012, 23(6), 1124-130

Electrochemical detection of Pb and Cd in paper-based microfluidic devices

Jianjun Shi; Fan Tang; Honglong Xing; Huxiang Zheng; Bi Lianhua; Wang Wei

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600018

Published online: May 24, 2012

J. Braz. Chem. Soc. 2012, 23(6), 1131-1139

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. Da Rocha Rosa; Héctor Fernández

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600019

Published online: May 29, 2012


J. Braz. Chem. Soc. 2012, 23(6), 1140-1145

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; Anthony D. A. Hansen

How to cite this article

 

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)

http://dx.doi.org/10.1590/S0103-50532012000600020

Published online: June 5, 2012

J. Braz. Chem. Soc. 2012, 23(6), 1146-1153

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; Mauro C. Santos

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600021


J. Braz. Chem. Soc. 2012, 23(6), 1154-1165

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; Maria Eliana L. R. de Queiroz

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600022

Published online: June 5, 2012

J. Braz. Chem. Soc. 2012, 23(6), 1166-1173

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; Razieh Zakerian

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600023

Published online: June 6, 2012

J. Braz. Chem. Soc. 2012, 23(6), 1174-1185

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; Marília O. F. Goulart

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600024

Published online: June 6, 2012

J. Braz. Chem. Soc. 2012, 23(6), 1186-1192

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; Ali Mousaviazar

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600025

Published online: June 6, 2012


Short Reports J. Braz. Chem. Soc. 2012, 23(6), 1193-1198

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; Valderi L. Dressler

How to cite this article

 

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

http://dx.doi.org/10.1590/S0103-50532012000600026

Published online: April 26, 2012

Online version ISSN 1678-4790 Printed version ISSN 0103-5053
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