Resumen en Inglés:

BiOCl/KBiO3 p-n heterostructures with hierarchical mesoporous architectures were successfully synthesized via a facile in situ method. The X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) results indicate the formation of heterojunctions between BiOCl and KBiO3. The photocatalytic performance of the as-prepared samples was investigated by the degradation of dye Rhodamine B (RhB) under visible light irradiation. BiOCl/KBiO3 composite has never been used to photodegrade the RhB which is a common dye and very difficult to degrade. The results demonstrated that KBiO3 combined with proper amount of BiOCl nanosheets exhibited high efficiency in the photocatalytic process, and BiOCl/KBiO3 with the molar ratio of 70/30 demonstrated the highest photocatalytic activity due to its large surface area, excellent charge separation characteristics and the suppressed recombination of electron-hole pairs. The results of active species detection reveal that the superoxide radical anions (O2-), hydroxyl free radicals (·OH), photogenerated holes (h+) and photogenerated electrons (e-) reactive species work together for the photocatalytic degradation of RhB. A possible and new mechanism of photocatalysis that differs from other teams was also explored and proposed. The present study will benefit the development of the new p-n heterojunction photocatalysts and would be of great importance to meet ever-increasing environmental demands in the future.

Resumen en Portugués:

The increase in the average temperature of the Earth due to excess CO2 and other greenhouse gases has caused glaciers to melt and sea levels to rise. The burning of fossil fuels is one of the main causes of this problem, so the use of biofuels is important for mitigating this environmental impact. In Brazil, biodiesel is mixed with mineral; however, irregularities have been detected, reducing the expected positive effects. Therefore, this study proposes the use of multivariate curve resolution with alternating least squares (MCR ALS) to quantify the content of methyl palm oil biodiesel in diesel blends and determine the concentration of the adulterant automotive lubricating oil in the blend. The model for quantifying biodiesel in diesel obtained R2 = 0.9997, root mean square error of calibration (RMSEC) = 0.56% (v v-1) and prediction (RMSEP) = 0.65% (v v-1), while the determination of adulteration in the biodiesel-diesel blend showed RMSEC = 0.67% (v v-1), RMSEP = 0.81% (v v-1) and R2 = 0.9992. These results demonstrate the ability of the models developed to predict both the content and quantity of possible adulterants in blends of palm oil biodiesel and mineral diesel, contributing to the quality control of this fuel.

Resumen en Inglés:

Coumarin derivatives possess diverse biological activities, encompassing antibacterial, antifungal, anticancer, antidiabetic, anti-inflammatory, and antioxidant effects. This study concentrates on the synthesis of two new coumarins: the first derived from rhizomes of Luvunga scandens and the second from 7-(diethylamino)-4-methyl-2H-chromen-2-one via bromination facilitated by NBS (N-bromosuccinimide) reagent. Their antibacterial and anticancer properties were evaluated in vitro, alongside in silico docking targeting the chromen-2-one group. Bromination of compound 1 yielded novel compound 2, while compound 4 was efficiently synthesized from 7-(diethylamino)-4-methyl-2H-chromen-2-one (3) using NBS. Testing on lung, breast, and liver cancer cell lines indicated that compound 2 effectively inhibited Staphylococcus aureus and Bacillus cereus at concentrations of 13.20 and 6.6 µM, respectively. It also demonstrated significant inhibition against MCF-7 breast cancer cells with a half-maximal inhibitory concentration (IC50) value of 50.37 ± 3.70 µM. Molecular docking revealed compound 2’s interaction with 2VF5 enzyme, elucidating its bacterial inhibition mechanism, with Gibbs energy and inhibition constant values of -7.42 kcal mol-1 and 3.62 µM, respectively. Additionally, compound 2 exhibited anticancer activity via alignment with topoisomerase 1 (3TOP): 1T8I, supported by molecular dynamics simulations illustrating strong ligand interactions. Analysis of pharmacophore kinetics highlighted the complex’s hydrophilic nature, indicating its potential therapeutic efficacy.

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Catalysts based on Ni-Me (Me = Co, Nb) supported on γ-Al2O3 were prepared by the coprecipitation-chemical deposition method via reflux, and hydrothermal method for oxidative dehydrogenation of ethane. For coprecipitation method, ammonia and urea were used as precipitating agents. In both methods, the Ni content was 30 wt.%, whereas that of Me (Co, Ni) was 5 wt.%. The activity and selectivity towards ethylene appeared to depend strongly on the composition of the catalysts and, interestingly, on the preparation conditions. In the present article, it is shown that mixed hydrothermal samples using urea showed the best performance. Specifically, the hydrothermally prepared NiNb/γ-Al2O3 sample was the one that showed the highest values. The introduction of Nb to Ni framework allowed to enrich with nucleophilic oxygen sites displayed via X-ray photoelectronic spectra (XPS) which lead to the formation of low reducible and selective sites.

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A stereoselective synthesis of α-aryl Z enaminones was developed by TfOH-promoted condensation of dibenzylidene ketones with organic azides. The cascade reactions involve the sequence of 1,3-dipolar cycloaddition of alkyl azides with the enone, aziridine formation, and 1,2-aryl migration via phenonium ion, whose stereochemical control by a strong N-H…O=C intramolecular hydrogen bond affords Z isomer exclusively. The readily available starting materials and ease of handling of TfOH are experimental advantages that give diversely substituted enaminones with total control of functionalization along the N-C=C-C=O conjugated system.

Resumen en Inglés:

This article aims to carry out a chemical and morphological study of ceramic artifacts prospected at the Ininga Archaeological Site, Teresina, PI, Brazil. These samples of historical value, which were produced by the Native American population of the Tupi ethnic group, were subjected to analysis by optical microscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence spectroscopy (FRX) and X-ray diffraction (XRD). The results demonstrated that there are similarities between the ceramic fragments, both macro and microscopically, demonstrating that there is a similar origin and manufacturing method between them. Thus, suggesting that they were all produced by the same human group and the pieces are contemporary with each other. Through the studies it was also possible to determine the most abundant chemical and mineral elements in the sample composition. Given all the data observed, and with the help of the archeology team responsible for the Site, which provided important data regarding the ceramic culture of the Tupi people, it was possible to conclude that the present study is of unique importance for the Ininga Archaeological Site, as it refers to pioneering identification and characterization work that will serve as a basis for subsequent studies.

Resumen en Portugués:

PRODUCTION OF BIONAPHTHA FROM (C3-C5) PRIMARY ALCOHOLS VIA CATALYTIC DEHYDROGENATION/DEHYDRATION PROCESSES. A sequence of dehydrogenation/dehydration reactions of homologous alcohols: propanol, butanol and pentanol was conducted using heterogeneous catalysts composed of mixed metal oxides basically of Mg and Al derived from hydrotalcites in the ratio M2+/Al3+ = 3, with 10 and 20% of the Mg substituted by Cu. The reactions were carried out in a fixed-bed reactor over a duration of 6 h at temperatures of 450 and 500 °C and yielded products of significant interest to the chemical industry. Product identification and quantification were achieved through gas chromatography coupled with mass spectrometry (GC-MS). A range of compounds were obtained, including alcohols, aldehydes, ethers, carboxylic acids, ketones, and hydrocarbons, with condensed alcohols and aldehydes being the predominant products. Reaction pathways were proposed for conversion of alcohols into their respective products, based on the Guerbet reaction mechanism. Catalysts containing copper proved to be more efficient in selectivity and stability throughout the reaction.

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The aim of this work was to study silica extraction from rice husk (RH) and rice husk ash (RHA). Bacterial cellulose (BC) was used to transport the extracted silica as well as the slow-release silica material. The silica extraction from RH and RHA was performed by leaching using ultrapure water and NaOH. Silica was quantified by UV-Vis spectrophotometer. BC membranes were produced with Komagataeibacter hansenii. Then, the membranes were impregnated with silica-rich leached extracts. Silica release tests under controlled conditions were conducted. Characterization of the impregnated membranes was conducted by Fourier transformed infrared spectrometry (FTIR), microstructural (scanning electron microscopy (SEM)) and mechanical resistance analyses. The results indicated that the RH and RHA leachates from the extractor solution containing NaOH contained more silica than did the extracts from ultrapure water. The BC membranes supported with the aqueous extract of RH released 58% of the adsorbed silica in 24 h. The BC membranes impregnated with RHA-H2O released 67% of the silica. The silica release reached 62% for RH and 60% for RHA from the extract leached with NaOH. The membranes showed a high capacity to retain both water and silica, which can be an alternative to reduce economic losses due to solubilization of fertilizers in the agricultural sector.

Resumen en Inglés:

The aim of this study was to evaluate the influence of different pressures of homogenization on whole milk powder with crystallized lactose on free fat content and particle size. Three homogenization pressure levels were applied. The powder produced at homogenization pressure of 75/5 MPa presented a smaller number of particles in the region < 1 μm (39.28%) and higher free fat content (13.78%) when compared to the powder produced at conventional homogenization pressure (15/5 MPa), which presented 59.40% particles in the region < 1 μm and 5.03% of free fat. Milk powder produced at 0/0 MPa presented the lowest number of particles in the region < 1 μm (24.60%) and the highest free fat content (19.39%). This study showed that the powder produced at a homogenization pressure of 15/5 MPa, which is commonly used in the industry, produces a crystallized milk powder with less suitable properties than the one obtained without homogenization.

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PHOTODEGRADATION IN SEMI-ARID CLIMATE IN PURE POLY(BUTYLENE ADIPATE-CO-TEREPHTHALATE) FILMS AND ADDITIVES WITH CLOVE ESSENTIAL OIL (Syzygium aromaticum (L.) Merr.). Active packaging is a type of material used to extend the shelf life of food, due to its interaction with the product. This study evaluated the natural photodegradation of pure poly(butylene adipate-co-terephthalate) (PBAT) films and additives with 5% essential oil of clove Syzygium aromaticum (L.) Merr. (OEC). To this end, 96 samples were exposed to solar radiation in the municipality of Custódia in Sertão/PE, with fortnightly collections for 180 days, annual repetition in the same climatic period, and analyses in triplicates. All samples exhibited susceptibility to solar radiation, as evidenced by the appearance of cracks, fragmentation, and yellowing of the material. The samples were more sensitive to thermal action after exposure as determined by TGA. The mass loss exhibits an increasing trend, reaching a maximum average value of 13%. A decreasing trend was observed for the carbonyl index and a slight increase in the hydroxyl index. Principal component analysis revealed a distinction of samples exposed for more than 60 days. Overall, the results indicate a comparable degradation pattern between pure PBAT samples and additives with 5% OEC in a natural atmosphere environment of a semi-arid climate.

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The ruthenium(II) complexes cis-[Ru(bpy)(phen)(ImN)(NO)](PF6)3 (I) and cis-[Ru(bpy)(phen)(SO3)(NO)](PF6) (II) (bpy = 2,2’-bipyridine, phen = 1,10’-phenanthroline and ImN = imidazole) were synthesized and characterized using UV-visible, infrared and NMR (nuclear magnetic resonance) spectroscopies and electrochemical techniques. Infrared bands in the 1910-1950 cm−1 range are consistent with NO+ stretching, indicating the coordination of nitric oxide. The UV-Vis results allowed for the identification of intraligand bands of bipyridine and phenanthroline ligands, as well as metal-to-ligand charge transfer (MLCT) bands for both polypyridine ligands in the wavelength range of 320 to 400 nm. Additionally, an MLCT band for the nitrosyl ligand was observed at about 469 nm. The voltammogram profiles displayed a single quasi-reversible process at 219 mV (complex I) and -102 mV (complex II), with both processes being related to the NO+/0 redox pair. The photochemical behavior of these complexes was studied, and NO release was observed upon blue light irradiation. The antibacterial activity of the complexes was tested against the bacteria Staphylococus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa, based on minimum inhibitory concentration measurements, in which no or moderate activity was observed against Gram-positive bacteria. However, complexes I and II showed good antimicrobial activity against Gram-negative Pseudomonas aeruginosa strains, being able to inhibit growth at low concentrations of 57.23 µmol L−1 for complex I and 200.8 µmol L−1 for complex II.

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The present study describes the antioxidant potential of ethanolic extracts of yerba mate (Ilex paraguariensis), coffee leaves (Coffea arabica) and jambolan pulp (Syzygium cumini Lamarck) when added to biodiesel, with and without chromium (Cr3+), manganese (Mn2+) and cobalt (Co2+) metal ions, measuring the induction period (IP) and the rate constant (k) of the oxidation reaction at 110 °C. Antioxidant activity was observed in all extracts, as they reduced k and increased the IP compared to the control sample. The coffee leaves extract had the most pronounced positive effect, increasing the IP to 12.42 h and reducing k by 5.9 times. However, biodiesel containing metallic ions of chromium, manganese and cobalt, both with and without natural extracts, reduced the IP in all assays conducted in this study. The natural yerba mate extract was the most affected by the manganese ion (Mn2+), reducing the IP by 41.61%. The chromium ion (Cr3+) had the least impact on the biodiesel oxidation process in the presence of coffee leaves extract, increasing the rate constant by 3.55%. Furthermore, the alcoholic jambolan pulp extract was the one that presented the best antioxidant properties in the presence of metal ions.

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Photocatalytic reduction of CO2 and H2O into valuable fuels is a promising and sustainable approach. Phosphate is crucial for the production of ATP (adenosine triphosphate), highlighting its significance in the transfer of energy essential for life. In this study, we design and prepare a modified TiO2 surface with phosphate to reduce CO2 using light. The TiO2+PO43- composite performs exceptionally well, producing CO at a rate of 36.93 μmol g-1 h-1, which is three times higher than pure TiO2, with nearly 100% selectivity for CO. Both experiments and theoretical analyses show that the phosphorus species create a channel for electron transfer between PO43- and Ti, improving charge movement. Modification by phosphate ions (PO43-) alters the surface microenvironment of TiO2, making it easier for more water molecules to be adsorbed on the surface. Furthermore, the PO43- modification adds more oxygen-containing functional groups to the surface. These groups act as sites that help in capturing and activating CO2. As a result, TiO2+PO43- stands out as a strong candidate for CO2 reduction, thanks to better charge transfer and more active sites.

Resumen en Portugués:

The northern region of Brazil, particularly the states of Pará and Amazonas, concentrates the majority of açaí national production. Considering the possible use of pesticides in this species, this study aimed to develop a comprehensive method for the multiresidue determination of pesticides in açaí pulp, using a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method with analysis by ultra-high performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS). Various parameters of extraction were investigated, and the method was successfully validated. Analysis by UHPLC-MS/MS provided high selectivity and sensitivity. The main modification to the original QuEChERS method was the use of the C18 adsorbent associated with primary secondary amine (PSA) in the clean-up step by dispersive solid phase extraction (d-SPE). The method was validated for 83 compounds, showing adequate accuracy (70 to 120%) and precision (RSD ≤ 20%). The method limits of quantification, established by recovery tests, ranged from 5 to 25 µg kg-1. The method limits of detection were from 1.5 to 7.5 µg kg-1. The method was applied to commercial samples of açaí pulp, and no pesticide residues were detected. The proposed method proved to be fast, efficient and suitable for multiresidue determination of pesticides in açaí pulp in routine analysis.

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Laboratory cultivation experiments were conducted under soil contamination using fluorescent lamps (50 and 100 mg kg−1 of Pb) to observe the seed germination and growth of tomatoes (Lycopersicum esculentum Miller) over 60, 90, and 120 days. The parameters selected to evaluate the impact of soil contamination on plant development included germination and survival rates, morphological characteristics such as the production of root, stem, and leaf tissues (masses), as well as changes in the chemical profile, with a focus on the polyphenolic content in the leaves. Tomato cultivation was determined to be viable, as evidenced by high germination and survival rates in soil unsuitable for traditional cultivation. Statistically significant differences in the masses of aerial parts, leaves, and stems were observed during the 120-day cultivation period when comparing plants in contaminated soil with control plants. Root masses showed no statistically significant differences throughout the entire cultivation period. In the case of tomato plants collected at 120 days, the assimilation of Cd was determined by ICP-MS (inductively coupled plasma mass spectrometry). As an adaptive response to contamination-induced stress, the tomato specimens produced 5-O-feruloylquinic acid.

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This study presents an artificial intelligence (AI)-based approach for predicting the thickness of electrodeposited zinc coatings on low carbon steel. The thickness of the coating is directly related to the corrosion resistance of the steel, according to the ABNT NBR 10476. The study investigates the influence of process time, ZnO/NaOH concentrations, anode material, and additives on coating thickness measured by X-ray fluorescence, employing the Hull cell method and a fractional factorial design. Statistical analysis and supervised machine learning algorithms, including multivariate regression, random forest, and extreme gradient boosting (XGBoost), were employed to develop prediction models. Among these models, XGBoost demonstrated superior performance with a coefficient of determination (R2) of 0.95 and a mean squared error (MSE) of 0.815, highlighting the effectiveness of AI in comparison to traditional regression methods. The AI models developed provide a valuable tool for the electroplating industry. They allow for the optimization of input parameters to achieve desired coating thicknesses and improve corrosion resistance. This ultimately reduces costs and improves product quality.

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A novel pretreatment method ionic liquid-based dispersive liquid-liquid microextraction followed by high-performance liquid chromatography (HPLC) was established and applied in the analysis of silychristin, silydianin, silybin, silybin B, isosilybin A, isosilybin B in Silybum marianum. The critical parameters affecting dispersive liquid-liquid micro-extraction (DLLME), including selection of dispersive solvent and extraction solvent, volume of dispersive solvent and extraction solvent, adjustment of pH, salt concentration, extraction time, were investigated by single factor study. Under optimum conditions, all of the target analytes presented good linearity (r > 0.9991) and satisfied recoveries (recoveries > 89.5%, relative standard deviation (RSD) < 4.6%). The limits of detection and quantification were 0.16 to 0.74 ng kg–1 and 0.42 to 2.52 ng kg–1, respectively. The developed method is sensitive, rapid, accurate and employable to simultaneously determine six target compounds in Silybum marianum.

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The growing global demand for energy and environmental concerns have driven the search for renewable fuel sources. This study investigated the production of renewable hydrocarbons through the catalytic pyrolysis of Jatropha curcas L. oil, using the mesoporous material KIT-6 impregnated with cobalt oxide (Co3O4) as the catalyst. The catalysts were characterized using techniques such as X-ray diffraction (XDR), X-ray fluorescence (XRF), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), and textural analysis. The catalytic cracking study was carried out through thermogravimetry and analytical pyrolysis. The mesoporous structure of KIT-6 was preserved after impregnation, although there was a reduction in surface area and total pore volume. The pyrolysis tests showed that Co/KIT-6 reduced the reaction temperature, favoring the formation of hydrocarbons in the C10-C18 range, suitable for biofuels such as biokerosene and green diesel. Compared to the thermal process, the use of the catalyst significantly increased the production of hydrocarbons while reducing the formation of undesirable oxygenated compounds. It is concluded that Co/KIT-6 is a promising catalyst for the sustainable production of biofuels from vegetable oils.

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FROM SAMPLING TO PURIFICATION: METHODOLOGIES AND TECHNIQUES FOR EVALUATION OF SILOXANES IN BIOGAS. Biogas has emerged as an important source of clean and renewable energy, with its energy viability dependent on purity grade. Primarily composed by methane and carbon dioxide, biogas can also contain nitrogen, water vapor, oxygen, hydrogen sulfide, ammonia, hydrocarbons and siloxanes. Regarding methane, all other components are considered contaminants, with volatile methylsiloxanes (VMSs) being the major challenge in terms of control and removal. VMSs are commonly found in personal care products and industrial applications, and their presence is highly detrimental to biogas energy generation equipment by forming silica deposits that cause fouling and damage, reducing operational efficiency and system longevity. In this context, three topics are crucial: (i) sampling techniques (bags, gas cylinders, canisters, adsorbent tubes, and impingers); (ii) detection and quantification methods for VMSs, highlighting gas chromatography coupled with mass spectrometry; and (iii) biogas purification/removal strategies (adsorption, absorption, refrigeration/condensation, biological degradation, and membrane separation). This review explores the methodologies involved in these topics, presenting literature research approaches and their effectiveness regarding siloxanes, contributing to biogas applications.

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The study of carbenes and metal carbenes has attracted researchers from different countries due to the versatility of these reactive species in preparative organic chemistry. In this review, we discuss the structural aspects, reactivity, and formation methods of carbenes, which provide theoretical support for understanding the structure/reactivity relationship of metal carbenes, whose classifications and formation methods have been presented. Emphasis is placed on the class of α-imino metal carbenes, which have allowed the construction of various heterocyclic compounds, including alkaloids with complex structures. Total and formal syntheses of nitrogen-containing compounds using α-imino metal carbenes from N-sulfonyl-1,2,3-triazoles have been reviewed. In this regard, an overview of the synthetic routes established in these works, including the key reactions highlighted by the authors, has been provided.

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The interaction between light and chemical reactions in photochemistry is essential for triggering previously inaccessible transformations and optimizing known reactions. Building efficient photoreactors faces challenges like temperature control, proper agitation, and safe light irradiation. The initiative to develop an affordable LED (light-emitting diode) photoreactor demonstrates the feasibility of adjustable versatile systems for different wavelengths, allowing reactions to be carried out on a microscale and a preparative scale. Furthermore, the importance of customized photoreactors is emphasized as they provide temperature stabilization, precise light exposure control, and the ability to adapt to different light sources, maximizing the efficiency and selectivity of photochemical reactions. This work presents the development and application of a low-cost, functional, adaptable, and efficient photoreactor. Practical evaluation conducted in the arylation of furan C-H showed adequate temperature control, good light irradiation intensity, appropriate wavelength of applied light, agitation for mixture homogenization, and reaction scale-up. The experimentally observed factors contribute to validating the reactor’s efficiency.

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The focus of this manuscript is to present the extension project “(Re)thinking the (in)differences: the deconstructions and resistance to transversal themes in the teaching of Natural Sciences”, as well as analyzing its potential when working with continued training work by teachers, promoting debate, discussion, and reflection on the use of contemporary cross-cutting themes in chemistry and science classes. It was also intended to stimulate class planning, the production of strategies and teaching material by educators motivated by the need to reform thinking and regenerate teaching, considering social themes that seek the empowerment of groups placed on the margins of the education system, so that they undertake training that is a collective achievement and built with social discussions.

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In this work we explore some theoretical and practical aspects of one-pot synthesis. The focal point of the study is the preparation of the thiazole heterocycle, with an emphasis on theoretical aspects of the organic and medicinal chemistry of this important privileged structure. The entire set of experimental procedures and characterization steps explored in this work has the potential to assist in the training and/or technical improvement of undergraduate students, and contribute to the teaching of chemistry in Brazilian higher education. It is worth emphasizing these aspects because the experiments shown in the proposed practices involve simple, rapid, low-risk, and low-cost procedures, making it perfectly feasible to reproduce them in undergraduate classes, even in laboratories with limited material resources.

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Acetylsalicylic acid (ASA) synthesized in the practical classes of experimental organic chemistry is generally discarded after the classes. Thus, the objective of this work is to find an alternative application for ASA and to promote awareness about the recycling of chemicals in educational and research environments. In addition, it explores the subsequent application of this synthesized ASA in the creation of powdered developers for latent fingerprints. The adopted methodology included the recrystallization of the previously synthesized ASA, followed by the development of three distinct formulations of powdered developers, which include ASA, lignin, and methylene blue. Subsequently, these powders were used to identify latent fingerprints, demonstrating that they are promising substances for such applications.

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The recent secondary curriculum reform in Brazil generated discussions around arguments for the inclusion of specific subjects within the official curriculum. This qualitative study, situated within a teacher education program at a university of São Paulo, investigates the arguments constructed by 31 pre-service teachers concerning the importance of Chemistry in the secondary curriculum. Findings highlight the impact of targeted instructional interventions on challenging pre-existing, naive conceptions held by them. Well-designed interventions foster the development of sophisticated arguments aligned with the value of scientific literacy for secondary students, reflecting deeper understandings of how chemistry education contributes to broader educational goals.

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This study investigated the reuse of papaya seeds for the extraction of benzyl isothiocyanate (BITC) as a context to foster the construction and deepening of chemical concepts in the initial training of chemistry teachers at the Federal University of Espírito Santo (UFES). Using Problematized Experimental Activity (PEA) as a teaching strategy, students conducted experiments to extract BITC from papaya seeds and applied ultra-violet (UV)-visible spectroscopy for its quantification. The results revealed that the highest BITC concentration was obtained from ethanolic extracts of dried seeds. At the end of the course, students developed teaching projects to incorporate this environmental theme into high school classes, reinforcing the relevance of contextualized chemistry teaching. The didactic intervention carried out in an environmental context contributed significantly to the training of future teachers, fostering meaningful learning and promoting a critical and conscious stance on the role of Chemistry in environmental issues.

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The study problematizes choices and traditional organizations of the chemical content in chemistry classes. The problematization is developed through an epistemological perspective, situated in the field of Chemistry Education, focusing on the construction of the concept of Chemical Bonds. It includes discussions in the fields of history and epistemology, but mainly presents the conceptions that preceded the nature of the Chemical Bonds concept proposed by Gilbert Newton Lewis, aiding in the understanding of its nature. This facilitates the creation of strategies and methodological practices that contribute to the teaching and learning process. We conclude that this study has enabled us to construct a pathway to understand the existing knowledge of that time and what contributed to Lewis’ proposal becoming the accepted theory by the scientific community of the time, persisting in Chemistry classes to this day.

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One of the best ways to consolidate the experimentation seen in practical Analytical Chemistry classes is to demonstrate to students how the knowledge contained in such discipline is present in everyday situations. Science communication is an important tool that can help in this regard. The aim of this study was to contribute to the learning of students in the discipline 7500030 - Qualitative Analytical Chemistry Laboratory (São Carlos Institute of Chemistry, University of São Paulo) by encouraging the elaboration of popular science texts, aiming to learn, debate, and share the concepts learned during practical classes. In the texts, students should inform which groups of the Periodic Table the cations studied during the semester belonged to and some particularities, such as day-life applications, always in clear and accessible language for a non-specialized audience or for those who are not familiar with such concepts. The students got involved in the project and all the delivered texts met the expectations of the proposed teaching activity, as they can disseminate the knowledge acquired during the practical classes. All groups of cations were addressed, 6 different types of texts were produced, and most students understood the importance of Qualitative Analytical Chemistry in identifying these cations.

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This paper presents the stages of an acceleration program focused on chemical technologies. We demonstrate how this initiative contributes to the creation of new businesses, startups, and technology licensing from research developed at Brazilian universities. The case of the program Escale-se is discussed. There were 66 technologies submitted, and 14 were selected for the pre-acceleration phase. In this phase, various contents were worked on, such as creating a business model and aspects of scaling hard-science technologies. Teams were evaluated by panels with market specialists, and 6 were selected for the second phase: pre-scaling/proof of concept. Here, proponents were encouraged to validate the business model by connecting with potential clients and partners, as well as planning the development and testing of the product in a relevant environment. Finally, one team was classified for the last stage: scaling/go-to-market - where they received R$ 100,000.00 to scale up their technology and create strategies for raising investments. Four of the fourteen technologies selected for the program opened National Register of Legal Entities (CNPJ) and raised approximately R$ 4.5 M in investments from different sources. These results demonstrate that the methodology contributed to the entrepreneurial development of participating researchers and the raising of funds for the businesses created.