Journal of the Brazilian Chemical Society 
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This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.Iron Nitrate Modified Cotton and Polyester Textile Fabric Applied for Reactive Dye Removal from Water Solution
In this work, we investigated the use of cotton scraps in natura and modified with iron nitrate, in the adsorption of one of the main water contaminants of the textile industries, the reactive black dye. Special attention was paid to the appropriate destination of the spent adsorbent, in compliance with the precepts of the circular economy. Cotton and polyester are excellent candidates for adsorbents and are produced on a large scale worldwide, but fabric wastes do not yet have a well-established method of application. We found that fabrics containing different types of fibers or colors maintain the ability to remove dye. ...
Source: Journal of the Brazilian Chemical Society - April 30, 2021 Category: Chemistry Source Type: research
Use of Paper Spray Mass Spectrometry for Determining the Chemical Profile of Green Cavendish Banana (Musa AAA) Peel and Pulp Flours and Evaluation of Its Functional Potential
Green Cavendish banana peel and pulp flours were obtained by three drying methods: oven dryer at 70 °C; air fryer at 180 °C and domestic oven at 180 °C, being the latter two new possibilities. Bioactive constituents using paper spray ionization mass spectrometry (PS-MS), phenolic identification and quantification by ultra-performance liquid chromatography with UV-Visible detection (UPLC/UV-Vis) and antioxidant capacity were evaluated. Phenolic acids showed distinct thermal stability between the treatments. Gallic acid was the predominant compound, ranging from (29.56 to 1211.74 mg 100 g-1) and had higher concentration ...
Source: Journal of the Brazilian Chemical Society - April 30, 2021 Category: Chemistry Source Type: research
A Catalysis Guide Focusing on C–H Activation Processes
From the recent development of catalytically controlled C-H activation with amenable synthetic routes obviating many challenges, the demand for this strategy has raised significantly to perform complex organic transformations. The impact of the achieved results in both homogeneous and heterogeneous catalysis reflects its efficacy in modern synthetic chemistry. A consolidated report and guidance of the methodologies involved in the previous and ongoing research in this domain would be very useful for the researchers to focus on more specific and selective C-H activation reactions to access desired complex molecular scaffold...
Source: Journal of the Brazilian Chemical Society - April 30, 2021 Category: Chemistry Source Type: research
Synthesis of a Homologous Series of Trialkyl Arsines (C3-C12) and Applications of Arsenic Triiodide as a Synthetic Precursor
This work presents some modifications in the post-synthetic processing for a classical arsenic reagent: AsI3. In comparison with the widely used analog, the trichloride, arsenic triiodide presents several advantages such as low toxicity, air stability, and low volatility. It was used as a synthetic precursor in the preparation of a variety of arsenic(III) derivatives like arsines, arsenites, and thioarsenites. Besides that, AsI3 was submitted to a diversity-oriented Grignard reaction in the preparation of a homologous series of trialkyl arsines ranging from AsC3H9 to AsC12H27. The series was analyzed by comprehensive two-d...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research
Efficient Synthesis and Antimicrobial Activities of Long Alkyl Chain Trifluoromethyl-1H-pyrazol-1-(thio)carboxamides and Trifluoromethyl-1H-pyrazol-1-yl-thiazoles
The synthesis of 3-alkyl-5-trifluoromethyl-1H- pyrazole-1-carboxamides, 3-alkyl-5-trifluoromethyl-1H-pyrazole-1-thiocarboxamides, and 2-(3-alkyl-5-trifluoromethyl-1H-pyrazol-1-yl)-thiazoles derivatives are reported. [3 + 2] cyclocondensations for a series of long alkyl chain 1,1,1-trifluoro-4-methoxyalk-3-en-2-ones and semicarbazide or thiosemicarbazide were carried out in ethanol, an eco-friendly medium. The series of trifluoromethyl-1H-pyrazol-1-yl-thiocarboxamide following a [3 + 2] cyclocondensation with 2-bromoacetophenone were converted into two series of 2-(3-alkyl-5-trifluoromethyl-1H-pyrazol-1-yl)-thiazoles. Good ...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research
Voltammetric Generation and Kinetic Stability of Nitro Anion Radical from Nitrofurazone in Ionic Liquids
The nitrofurazone (NF) electrochemical reduction has been studied by cyclic voltammetry (CV) and square wave voltammetry (SWV) in non-aqueous medium using three different ionic liquids (IL): BMImTf2N, BMImBF4 and BMMImTf2N, having a carbon fiber microelectrode as working electrode. In all of them, two reversible cathodic peaks were recorded for NF. Under higher frequency values, only one reversible cathodic peak was registered. The systems reversibility could also be observed by CV, since a reversible redox couple was registered for this reduction. The systems reversibility with product and reagent adsorptions on the elect...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research
Agroindustry Residues as a Source for Cellulose Nanofibers Production
Our study was motivated by the large amount of crop residues produced in Brazil, which represent underutilized waste biomass and a serious threat to the environment because of the landfilling. For example, even though the corn crop is not popular in Brazil, it is produced in the area of around 18-20 million hectares with an average production of 5-6 t ha-1. That is the reason to seek for the crop residues value-added applications as proposed in the present study. Four Brazilian crop waste biomass: orange bagasse, corn husks, sugarcane straw and coffee residues were used for cellulose nanofibers (CNF) production. CNFs were ...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research
First-Principles Calculations of a New Semi-Conductive Carbon Allotrope Named ABF-Carbon
Carbon is an extremely versatile element and can generate a plethora of structures with distinct properties. Proposing new possible metastable allotropic structures for carbon has been the subject of increasing interest over the past few years. In this contribution, we present a new carbon allotrope, named ABF-Carbon, based on the connection of spiropentadiene molecular motif and sp3 carbon atoms. This new structure is a metastable carbon allotrope formed by 6 carbon atoms, being 2 sp2 and 4 sp3, in a body-centered tetragonal with space group (space group 119) and point group . By first-principles calculations using the de...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research
Improving Photoluminescence Quantum Yield of CdTe Quantum Dots Using a Binary Solvent (Water + Glycerin) in the One-Pot Approach Synthesis
The present work describes the comparison of the optical and structural properties between CdTe quantum dots (QD) synthesized in water and in the binary solvent (water + glycerin) via one-pot approach synthesis. The optical properties of the nanocrystals obtained with different synthesis parameters were characterized by UV-visible and photoluminescence spectroscopies. The structural chracterization were performed by Fourier transform infrared spectroscopy (FTIR), zeta potential, size-distribution by dynamic light scattering (DLS), X-ray diffraction (XRD), and also by high-resolution transmission electron microscopy (HRTEM)...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research
[5]Helicene-Scaffold Fluorescence Sensing for Selective Detection of Au3+ Ions and Gold Nanoparticle
A new quenching fluorescence sensor (MDP) with high productivity was easily synthesized from a [5]helicene anhydride derivative and propargyl bromide. This MDP sensor has significant photophysical properties, including high fluorescence emission and a large Stokes shift, and it exhibits selectivity and an excellent detection response in distinguishing Au3+ ions from interfering metal ions in aqueous solution. The limit of detection of the sensor were determined to be 0.16 µmol L-1 or 32.0 ppb. Stoichiometric binding between the MDP and Au3+ ions was found to occur at a 1:2 ratio. Additionally, the MDP sensor shows an abil...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research
Alternative Approaches Applied to Inductively Coupled Plasma Techniques: Multi-Flow and Two-Flow Calibration
Multi-flow calibration (MFC) is based on monitoring the analytical signal from a single calibration standard solution at several different nebulization gas flow rates (Q), which normalizes plasma conditions and minimizes matrix effects. In the present study, MFC was evaluated, for the first time, applied to inductively coupled plasma optical emission spectrometry (ICP OES) and inductively coupled plasma mass spectrometry (ICP-MS) to analyze different and complex-matrix samples. Al, As, Cd, Cr, Cu, Mn, Pb, and Zn were determined by ICP OES, while As, Cd, Co, Cu, Hg, Mo, Mn, Ni, Se, Sb, Pb, and V were determined by ICP-MS. M...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research
Reduced Graphene Oxide-Cadmium Sulfide Quantum Dots Nanocomposite Based Dispersive Solid Phase Microextraction for Ultra-Trace Determination of Carbamazepine and Phenobarbital
This research presents a fast, sensitive, and selective ultrasound-assisted dispersive solid phase microextraction technique for simultaneous preconcentration and determination of ultra-trace amount of carbamazepine and phenobarbital. Reduced graphene oxide sheets decorated with cadmium sulfide quantum dots was synthesized, characterized, and used as a high capacity adsorbent. A high performance liquid chromatography with UV detector (HPLC-UV) instrument with 58:42 composition of methanol:acetic acid/acetate buffer (pH = 5; 0.05 mol L-1) as the mobile phase and set on the wavelength of 230 nm was used to separate and quant...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research
Development and Validation of a Gas Chromatographic Method for the Quantification of Minor Alkaloids in Cocaine
The quantification of minor alkaloids in seized cocaine can provide information for drug profiling and law enforcement initiatives. This work presents the development and validation of an analytical method to quantitate minor alkaloids in cocaine samples using gas chromatography with flame ionization detector, after derivatization. The method was validated in accordance with the ISO/IEC 17.025:2017 requirements. The calibration was linear (determination coefficient (R2) ≥ 0.998), ranging from 1.0 to 3,500 mg L-1 for all target analytes with suitable selectivity and precision (relative standard deviation lower than 10%)....
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research
Thermal and Catalytic Fast Pyrolysis of Oily Extracts of Microalgae: Production of Biokerosene
Three different microalgae species, Desmodesmus sp., Nannochloropsis oculata and Halamphora coffeaeformis were grown under controlled conditions. The resulting dry biomass was characterized by TG-DTA (thermogravimetry-differential thermal analysis) and extracted with three solvents having different polarities. The extracts gross mass yields varied from 2% using n-hexane to 23% (or 74% when subtracting the volatiles and ashes) when using methanol-chloroform whatever the microalgae species. Fourier transform infrared (FTIR) spectra of all extracts suggested the presence of fatty esters and acids. The extracts were pyrolyzed ...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research
In silico Evaluation of Cucurbit[6]uril as a Potential Detector for Cocaine and Its Adulterants Lidocaine, Caffeine, and Procaine
Illicit drugs and their trafficking require worldwide efforts in investigation, detection, and control. Colorimetric tests are often applied to identify drugs. Cocaine has some well-known adulterants that can provide a false positive response. Cucurbit[6]uril (CB[6]) has been suggested as a potential detector for cocaine and other illicit drugs. This work uses in silico methods to evaluate the use of CB[6] to detect cocaine and these interfering substances. More specifically, this work analyzes different possibilities of CB[6] complexation with cocaine, lidocaine, caffeine, and procaine and compares the results achieved fo...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research
