Abstract in English:Improvements in Sustainable Organic Synthesis are usually related to the investigation of less hazardous, non-corrosive and renewable materials, as well as waste prevention, energy efficiency, solvent-free reactions, and the development of efficient reusable catalysts. In this context, multicomponent reactions emerged as important strategies for the rapid and more sustainable synthesis of organic molecules. In addition, the use of task-specific ionic liquids as non-conventional solvents and/or catalysts in multicomponent reactions has recently received great attention, contributing to the development of greener synthetic methodologies. This review describes the studies on the use of structurally diverse homogeneous and heterogeneous sulfonic acid-functionalized task-specific ionic liquids as acidic catalysts for multicomponent reactions applied to the synthesis of nitrogen- and oxygen-based heterocycles, as well as related compounds. The combination of the green credentials of multicomponent reactions and acidic ionic liquids are able to improve process sustainability and green metrics, contributing to sustainable chemical development and, ultimately, to economic growth and cleaner industrial production.
Abstract in English:Palladium-catalyzed carbonylation reaction has surfaced as a robust tool for insertion of the carbonyl group into organic molecules, and in the last decades enormous progress has been made. Nowadays, a plethora of methodologies is available to synthesize all kinds of carbonyl compounds. However, the focus has shifted during recent years to address rising concerns related to developing safe, cost-efficient, and more sustainable methodologies. The use of different carbon monoxide (CO) precursors/sources, avoiding handling of highly toxic and flammable gaseous carbon monoxide, and substituting nonrenewable solvents for those derived from renewable feedstock have contributed to aim these goals. In this review, we will discuss the advent of the application of renewable solvents to improve the sustainability and environmentally benign nature of Pd catalyzed carbonylation reactions.
Abstract in English:For billions of years, the phenomena of life and biocatalysis have been intertwined. If in the beginning biocatalysis was fundamental for the origin of life, currently it is very important for the cleaner production of pharmaceuticals and fine chemical intermediates. There is no doubt that drugs have brought great benefits to humanity, but currently, the expectations of modern society are focused on drugs with greater safety, less environmental impact, more sustainable practices, and less energy use. This review intends to show how the challenges for the production of some low molecular weight drugs produced by synthetic routes that involve at least one biotechnological step using microorganisms or enzymes were faced. These biotechnological drug production routes are more sustainable than conventional synthetic routes, as they produce a much smaller amount of waste, use moderate reaction conditions, have lower energy consumption, and have lower metal consumption, in addition to being more selective. Additionally, many natural products have structures too complex to be produced exclusively by chemical routes. The large-scale and economical production of these drugs is of great importance for fighting cancer as well as inflammatory, infectious, autoimmune, metabolic, hormonal, cardiovascular, and neurological diseases, among others.
Abstract in English:Sustainable analytical methods are highly demanded in the modern society. Within the green principles, novel procedures that attend the sustainable development goals have been proposed and the internet of things (IoT) can play key role to achieve this goal. The association of IoT with analytical chemistry enables the real-time obtaining of analytical data to control industrial processes as well as for monitoring different environmental scenarios and human health by accessing remotely analytical information. In this context, this review presents the main IoT technologies used for analytical chemistry as well as a tutorial for beginners in the field.
Abstract in English:A green methodology was developed for the extraction and determination of lauryl ether sulfate in raw materials and commercial liquid soap and shower gel samples. The method avoids the use of organic solvents, offering a simple, cheap, and safe analysis. The methodology is based on the sorption of an ionic pair consisting of a cationic dye and an anionic surfactant onto polyurethane foam. The experimental variables were optimized by chemometry to obtain the conditions that maximized extraction of the ionic pair. Digital imaging and spectrophotometry were used for quantification in the linear concentration range from 10.0 to 100 mg L-1. The limits of detection and quantification were, respectively, 2.71 and 9.28 mg L-1 for digital imaging, and 1.74 and 5.83 mg L-1 for spectrophotometry. The methods showed good results when applied to commercial samples, with recoveries in the range 96.8-103%.
Abstract in English:Various beneficial biological activities have been reported for passion fruit (Passiflora edulis), grown in tropical and subtropical regions. However, no study has yet demonstrated its action against the Zika virus (ZIKV) infection. The present study aimed to investigate the anti-ZIKV of the ethanolic passion fruit seed extract (PFSE), from which, liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis allowed to putatively annotate the occurrence of piceatannol, astringin, scirpusin A, scirpusin B, isookanin-7-O-glucoside and naringenin-7-O-glucoside, two quadranguloside derivatives, tyrosine, and phenylalanine. PFSE is well tolerated by cell lines (Vero E6 and HTR-8/SVneo) and tissue explants from the human placenta. With 1- and 24-h treatments, PFSE consistently reduced the viral load and NS1 protein expression of the two strains of ZIKV (MR766 and PE243) in placental explants and cell lines. Thus, PFSE has a promising potential for developing anti-ZIKV treatments, protecting the placenta against infection caused by ZIKV, along with relevant antioxidant potential, represented by ferric reducing antioxidant power (FRAP) of 390.5 Trolox eq per g dry extract and half maximal inhibitory concentration (IC50) for 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) of 12.1 µg mL-1, and more than 90% protection from lipid peroxidation. Although further studies need to be conducted, PFSE treatment was safe and effective in trophoblast cells and placental explants, thus representing a promising class of all-accessible products based on the reuse of industrial by-products.
Abstract in English:This work provides a general insight on lipase-catalyzed synthesis of geranyl acetate through esterification of geraniol with acetic acid. Although this reaction is relatively well known, the replacement of organic solvents by supercritical fluids is fairly recent and the role of CO2 is still not completely understood. Therefore, reactions were performed with Lipozyme® RM IM and Novozym® 435 as biocatalysts, and hexane and CO2 as solvents. For similar reaction conditions, geraniol conversions obtained using hexane were much higher, rather than supercritical CO2 (scCO2, 82.9% versus 12.0% after 4 h). The results obtained indicated that CO2 might help the migration of water from the enzyme surface to reaction bulk and then to the vapor phase. Thus, by increasing the vapor phase extension, the geraniol conversion enhanced to 60.5% after 4 h. Such improvement represents one step forward to comprehend the influence of CO2, a safer and greener solvent as compared to hexane.
Abstract in English:Tin oxide (SnO2) nanoparticles were synthesized by the co-precipitation method and mechanically modified by high-energy ball milling. The experimental results demonstrate that the collision with zirconia balls produces slight changes in the crystalline, electronic, morphological, and surface properties of SnO2, which lead to an increase in the redox potential of the energy level and the formation of the hydroxyl group on the SnO2 surface. Moreover, these changes are intensified over the milling up to 90 min, directly affecting the photocatalytic performance, which was monitored by the rate of rhodamine B (RhB) degradation driven by ultraviolet (UV) irradiation. As a result, all ground samples showed better photocatalytic activity than pristine SnO2 (Sn-cop). The maximum degradation of rhodamine B was ca. 75%, achieved with 90 min-milled SnO2 nanoparticles (Sn-M90), compared to the Sn-cop sample induced a 1.67 times higher degradation rate. The reaction mechanism suggests that its better photocatalytic activity may be associated with the higher increased redox potential of the valence and conduction bands and the formation of hydroxyl active sites on the catalyst surface principal oxidizing agent generated. Therefore, we conclude that the ball milling process is an efficient way to induce stable activation of oxide metal for photocatalytic applications.
Abstract in English:Terpenes are the most abundant class of natural product that exist in nature. They possess a myriad of industrial applications including pharmaceutical, perfumery and flavors, bulk chemicals, and fuel. Intriguingly, until today, the vast majority of characterized terpenoids have been isolated from plants and fungi, and only in recent years bacteria were found to generate a representative reservoir of terpenoids molecules. Mining Streptomyces sp. CBMAI 2042 genome data has revealed the presence of five terpene cyclase genes. Chemical analysis of mycelium extract of this bacteria strain has unveiled at least 28 volatile terpenes molecules, where three encoding sesquiterpene cyclase (STC) genes are apparently responsible for their biosynthesis. The cyclic products obtained by incubation of these three purified recombinant STCs with farnesyl diphosphate (FPP) were analyzed by gas chromatography-mass spectrometry (GC-MS) and identified using the Van den Dool and Kratz equation.
Abstract in English:Here we investigated the photoelectrodeposition of oxygen-evolving catalysts (OECs) based on oxy-hydroxides-phosphates of Co, Fe, or Ni (CoPi, FePi, and NiPi) on the WO3/BiVO4 heterojunction and their activity in water oxidation. The OECs were deposited by cycles of (i) open-circuit potential (OCP) and (ii) applying a potential positive enough to oxidize the metallic precursor on the WO3/BiVO4. The crystalline and optical properties of the photoanodes were not significantly affected by the OECs deposition. However, there was a remarkable increase in the photocurrent densities (jpc) to water oxidation, where the modification with FePi showed the best result, achieving 2.12 mA cm-2, which corresponds to 2.83 times higher than the heterojunction without the OECs. Furthermore, the OECs deposition changed the morphology of the heterojunction with the deposition of a thin film on its surface. In addition, during the FePi deposition, the BiVO4 layer seems to partially dissolve. Our study shows a facile methodology to boost the activity of photoanodes to the water oxidation by photoelectrodeposition of OECs.
Abstract in English:Additive manufacturing is an emerging tool that has contributed to the sustainable fabrication of devices in several areas based on the concept of “zero waste”. Considering extrusion-based manufacturing (or 3D printing), polylactic acid (PLA) has been highlighted due to its biodegradability, obtention from renewable sources, and compatibility for 3D printing. Composites of PLA with conducting fillers, such as carbon-black (CB/PLA), are commercially-available and compatible with extrusion-based 3D printers and 3D pen. Herein, we investigate the electrochemical behavior of several antioxidant species (catechol, hydroquinone, propyl-gallate, octyl-gallate, dopamine, gallic acid and pyrogallol (PY)) on 3D-printed electrodes. Experiments by cyclic voltammetry demonstrated that electrochemical surface treatment in NaOH aqueous solution is an important strategy to improve the response of all antioxidants. Thus, PY was selected to evaluate the analytical performance of the proposed 3D-printed sensor. For this, a fast and simple method using batch-injection analysis with amperometric detection (BIA-AD) has been developed, which showed a limit of detection of 0.15 µmol L-1, wide linear range (0.5 to 300 µmol L-1), good precision (relative standard deviation (RSD) < 3.4%) and selectivity. This method was applied in biodiesel samples, after dilution (400-fold) in electrolyte. Recovery percentages ranging from 82 to 119% attested absence of matrix effect and good accuracy.
Abstract in English:Conductive polymers are versatile materials that can be applied in many different technology fields, especially green energy. They have several advantages, such as easy synthesis, low density, and cost. However, its electric conduction property is also related to material aging with great loss of their characteristics, limiting their applicability. The in-depth study of electrochemical aging can provide useful information for new strategies to overcome this problem. Thus, this work describes the use of factorial design to evaluate the influence of some synthesis variables on the aging of poly(3-hexylthiophene): electrolyte and monomer concentration and water in the synthesis of non-aqueous solution. For this, the properties of the films were evaluated by cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy. The accelerated electrochemical aging was performed by applying a potential higher than the superoxidation potential for 20 min steps. It was possible to identify two extreme cases, the conventionally synthesized polymer aged more, while the polymer obtained with the three altered parameters suffered fewer aging effects. It was possible to identify a range of different aging pathways among these. The mechanical stress caused by the several oxidation/reduction cycles of the material aligned to the increasing loss of polymer properties, potentiates aging.
Abstract in English:The aim of the current study was the valorization of hesperidin, the dominant flavonoid in citrus processing waste, by microwave-assisted synthesis of hesperidin-Mg complex, improving its antioxidant activity and insecticidal potential. Here we show, for the first time, that microwave-assisted synthesis of [Mg(hesp)2(phen)]OAc (1) (hesp: hesperidin, phen: phenanthroline) improve the reaction rate and yield. The nuclear magnetic resonance (NMR) experiments proved to be powerful tools for the identification of three isomers in metal complexes. Moreover, we explore the insecticidal potential of 1 and [Mg(phen)2(Isov)]OAc (2) (Isov : isovanillic acid) complexes against three insects. Complex 1 killed 80% of adults whitefly at 0.14 μmol L-1, and 2 76% at 0.36 μmol L-1. There was a total mortality of Spodoptera frugiperda with 2 at 0.39 μmol L-1, and 83% with 1 at 0.14 μmol L-1. Both have similar activity, and represent a novel group of insecticide for Bemisia tabaci and S. frugiperda; nevertheless, the benefits of both as Myzus persicae repellent require further evaluation.
Abstract in English:Thermal infrared enthalpimetry (TIE) was used for hypochlorite determination in commercial hypochlorite-based bleaching solutions. Experimental parameters were evaluated for the reaction with a hydrogen peroxide solution. The most relevant conditions were 5% H2O2 (m/m) solution, stirring speed of 250 rpm, dispensing rate of 0.57 mL s-1, and 10 s after reaction for the simultaneous temperature readings of four replicates. Agreement to reference method NBR 9425 ranging from 98.2 to 103.2% was achieved, with a low variation among measurements (relative standard deviation < 3.5%). The number of analytical operations was reduced, and only H2O2 solution was required as a greener reagent. A low amount of residues was generated (2.4 and 152.8 mL for each replicate in TIE and official method, respectively), and the application of the green analytical procedure index (GAPI) showed the greenness of the proposed method.
Abstract in English:To preserve human health, persistent organic pollutants (POPs) and current-use pesticides (CUPs) should be monitored in fatty tissues, including breast milk. Therefore, this study aimed to optimize sample preparation conditions using a 32 factorial design for the determination of POPs and CUPs by gas chromatography coupled to mass spectrometry with negative chemical ionization (GC-NCI-MS). The method was validated for 57 POP and CUP compounds using hexane:acetone for extraction and clean-up by dispersive solid phase extraction (d-SPE) with Florisil®. The matrix effect was compensated by extracted analytical calibration. Method validation showed satisfactory results with limits of detection of 3 to 13 ng g-1 of fat. The method presented adequate accuracy (recoveries from 72 to 117%) and precision (relative standard deviation (RSD) ≤ 18%) and was applied to breast milk samples from Rio Grande do Sul State, southern Brazil, wherein all samples contained at least one compound. With principal component analysis, it was possible to associate the pesticides detected with the city of origin of the samples and the number of pregnancies of nursing mothers. Additionally, the analytical method was effective for the determination of trace levels of POPs and CUPs in breast milk and can be applied in biomonitoring studies.