Pub Date : 2023-08-25DOI: 10.21577/0103-5053.20230022
F. Furlan, M. Matsushita, Aline Coqueiro, P. Março, P. Valderrama
Ora-pro-nobis (Pereskia aculeata Mill) is an unconventional food plant (UFP) rich in proteins, vitamins, fibers, and antioxidants. In this study, ora-pro-nobis leaves were investigated as a proof‑of‑concept by near-infrared (NIR) spectroscopy concerning the storage time (from collection to 12 days), packaging system: styrofoam-based packaging covered with stretchable polychloride vinyl (PVC) film, and vacuum packaging (nylon/poly), temperature (at room temperature of 20 ºC, and in the refrigerator at 4 ºC), and sanitization condition (washed and without washing). Principal component analysis (PCA) was applied to augmented matrices, showing that unwashed leaves stored in the refrigerator with styrofoam-based packaging covered with PVC film were better preserved over time. Furthermore, it has been suggested that NIR absorptions are related to proteins, carbohydrates, lipids, vitamins, antioxidants, and water from ora-pro-nobis leaves and their physiological reactions over time. By combining NIR spectroscopy and chemometrics, a complete understanding of the shelf life of ora-pro-nobis leaves was achieved.
{"title":"Assessment of Ora-Pro-Nobis (Pereskia aculeata Miller) Leaves Shelf-Life in Different Conditions by Using NIR Spectroscopy and Augmented Matrices with Chemometrics","authors":"F. Furlan, M. Matsushita, Aline Coqueiro, P. Março, P. Valderrama","doi":"10.21577/0103-5053.20230022","DOIUrl":"https://doi.org/10.21577/0103-5053.20230022","url":null,"abstract":"Ora-pro-nobis (Pereskia aculeata Mill) is an unconventional food plant (UFP) rich in proteins, vitamins, fibers, and antioxidants. In this study, ora-pro-nobis leaves were investigated as a proof‑of‑concept by near-infrared (NIR) spectroscopy concerning the storage time (from collection to 12 days), packaging system: styrofoam-based packaging covered with stretchable polychloride vinyl (PVC) film, and vacuum packaging (nylon/poly), temperature (at room temperature of 20 ºC, and in the refrigerator at 4 ºC), and sanitization condition (washed and without washing). Principal component analysis (PCA) was applied to augmented matrices, showing that unwashed leaves stored in the refrigerator with styrofoam-based packaging covered with PVC film were better preserved over time. Furthermore, it has been suggested that NIR absorptions are related to proteins, carbohydrates, lipids, vitamins, antioxidants, and water from ora-pro-nobis leaves and their physiological reactions over time. By combining NIR spectroscopy and chemometrics, a complete understanding of the shelf life of ora-pro-nobis leaves was achieved.","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68330822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-25DOI: 10.21577/0103-5053.20230045
Liane Carvalho, C. Bezerra, C. D. da Rocha, Letícia de Oliveira, Luna Vasconcelos, S. Santana
Rutin is found in several plant sources and has therapeutic effects with excellent healing potential. Its use is restricted due to its low aqueous solubility, requiring a carrier matrix that allows an adequate delivery system. Biopolymer matrices can release the active ingredient in a controlled manner, keeping it within the therapeutic range and minimizing side effects. This study used babassu mesocarp starch films prepared by different routes as Arrabidaea brachypoda DC Bureau (AB) leaf extract carrier matrices to produce a controlled release system. The films were produced by the casting method, and the AB extract was incorporated in the proportion of 0.5% m/m of dry starch. The presence of the extract in the matrix was identified with Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD) data and functional analyses. The in vitro release of the AB extract was carried out in phosphate-buffered saline, pH 7.4, and adapted to the Korsmeyer-Peppas model, with coefficients of determination (R2 ) ≥ 0.9018. The release exponents (n) revealed that the release mechanism is diffusion controlled. Different kinetic constant values (k) indicated that the treatments employed allowed slower and more controlled release profiles, according to the route chosen for matrix preparation. Thus, the materials produced emerge as a new approach to releasing vegetable extracts.
{"title":"Controlled Release of Rutin from Babassu Coconut Mesocarp Starch Films","authors":"Liane Carvalho, C. Bezerra, C. D. da Rocha, Letícia de Oliveira, Luna Vasconcelos, S. Santana","doi":"10.21577/0103-5053.20230045","DOIUrl":"https://doi.org/10.21577/0103-5053.20230045","url":null,"abstract":"Rutin is found in several plant sources and has therapeutic effects with excellent healing potential. Its use is restricted due to its low aqueous solubility, requiring a carrier matrix that allows an adequate delivery system. Biopolymer matrices can release the active ingredient in a controlled manner, keeping it within the therapeutic range and minimizing side effects. This study used babassu mesocarp starch films prepared by different routes as Arrabidaea brachypoda DC Bureau (AB) leaf extract carrier matrices to produce a controlled release system. The films were produced by the casting method, and the AB extract was incorporated in the proportion of 0.5% m/m of dry starch. The presence of the extract in the matrix was identified with Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD) data and functional analyses. The in vitro release of the AB extract was carried out in phosphate-buffered saline, pH 7.4, and adapted to the Korsmeyer-Peppas model, with coefficients of determination (R2 ) ≥ 0.9018. The release exponents (n) revealed that the release mechanism is diffusion controlled. Different kinetic constant values (k) indicated that the treatments employed allowed slower and more controlled release profiles, according to the route chosen for matrix preparation. Thus, the materials produced emerge as a new approach to releasing vegetable extracts.","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68333338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-25DOI: 10.21577/0103-5053.20230046
Mayra F. Costa, M. Borges, V. Chapla, C. Biasetto, Isabele R. Nascimento, V. Bolzani, Â. Araújo
A new compound, (6R,7S,2E,4E)-6,7-dihydroxy-4,6-dimethylocta-2,4-dienoic acid (1), together with eight known compounds were isolated from the co-culture of Saccharicola sp. and Botryosphaeria parva, an endophytic fungi associated with Eugenia jambolana Lam. (Myrtaceae) plant species. The structures were elucidated by spectroscopic analysis of the one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) and mass spectrometry (MS) data as well as by comparison with literature data. The bioactivity (antioxidant and antifungal) of the crude EtOAc was evaluated. All crude extracts presented antioxidant activity and only the crude extract from the co-culture was active on the fungus Cladosporium sphaerospermum. This investigation contributed to the knowledge about the metabolic production of two endophytic fungi Saccharicola sp. and Botryosphaeria parva in co-culture, once, until the present date, there are no studies in the literature that report the understanding of the chemical interaction of both grown in the same environment.
{"title":"Evaluation of the Metabolic Production from the Co-Culture of Saccharicola sp. and Botryosphaeria parva, an Endophytic Fungi Associated with Eugenia jambolana Lam.","authors":"Mayra F. Costa, M. Borges, V. Chapla, C. Biasetto, Isabele R. Nascimento, V. Bolzani, Â. Araújo","doi":"10.21577/0103-5053.20230046","DOIUrl":"https://doi.org/10.21577/0103-5053.20230046","url":null,"abstract":"A new compound, (6R,7S,2E,4E)-6,7-dihydroxy-4,6-dimethylocta-2,4-dienoic acid (1), together with eight known compounds were isolated from the co-culture of Saccharicola sp. and Botryosphaeria parva, an endophytic fungi associated with Eugenia jambolana Lam. (Myrtaceae) plant species. The structures were elucidated by spectroscopic analysis of the one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) and mass spectrometry (MS) data as well as by comparison with literature data. The bioactivity (antioxidant and antifungal) of the crude EtOAc was evaluated. All crude extracts presented antioxidant activity and only the crude extract from the co-culture was active on the fungus Cladosporium sphaerospermum. This investigation contributed to the knowledge about the metabolic production of two endophytic fungi Saccharicola sp. and Botryosphaeria parva in co-culture, once, until the present date, there are no studies in the literature that report the understanding of the chemical interaction of both grown in the same environment.","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68333527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-25DOI: 10.21577/0103-5053.20230047
C. Wosch, Ricardo Labes, K. Salome, Vitor Melo, Renan R. Schorr, Palimécio Guerrero Jr., N. Lima, Gustavo Frensch, B. Maia, F. Marques
Asymmetric addition of organozinc compounds to carbonyl groups is one of the most useful methods for the synthesis of alcohols with high enantioselectivity. There is a wide range of chiral catalysts, although their synthesis requires more than one step and not often readily available starting materials. In this work, chiral β-hydroxy oxazolines derived from (+)-camphor and (−)-fenchone were easily synthesized through a one-step method, with good yields. Both ligands were evaluated as catalysts for the stereoselective addition of diethylzinc to aromatic aldehydes. All ligands showed good catalytic activity, leading both to the preparation of the R enantiomer of chiral secondary alcohols. As ligand 2 provided slightly better enantioselectivities, it was used as chiral inductor for the addition of diethylzinc for a larger number of aldehydes, resulting in good to excellent yields (88-98%) and enantiomeric excess up to 96%.
{"title":"New Catalysts Derived from Natural Products as Highly Stereoselective Chiral Inductors for Diethylzinc Addition to Aromatic Aldehydes","authors":"C. Wosch, Ricardo Labes, K. Salome, Vitor Melo, Renan R. Schorr, Palimécio Guerrero Jr., N. Lima, Gustavo Frensch, B. Maia, F. Marques","doi":"10.21577/0103-5053.20230047","DOIUrl":"https://doi.org/10.21577/0103-5053.20230047","url":null,"abstract":"Asymmetric addition of organozinc compounds to carbonyl groups is one of the most useful methods for the synthesis of alcohols with high enantioselectivity. There is a wide range of chiral catalysts, although their synthesis requires more than one step and not often readily available starting materials. In this work, chiral β-hydroxy oxazolines derived from (+)-camphor and (−)-fenchone were easily synthesized through a one-step method, with good yields. Both ligands were evaluated as catalysts for the stereoselective addition of diethylzinc to aromatic aldehydes. All ligands showed good catalytic activity, leading both to the preparation of the R enantiomer of chiral secondary alcohols. As ligand 2 provided slightly better enantioselectivities, it was used as chiral inductor for the addition of diethylzinc for a larger number of aldehydes, resulting in good to excellent yields (88-98%) and enantiomeric excess up to 96%.","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68333720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-25DOI: 10.21577/0103-5053.20230034
Jéssica Raíssa Guimarães, Yves Nathan de Faria, Mateus de Oliveira, L. Manzato, Cláudia Silva
Concrete slurry waste is a material removed from sedimentation tanks that receive water used to wash concrete mixer trucks and patios of concrete batching plants (CBP). The objectives of this study were to determine the chemical composition of this residue from three different producers, in three consecutive months and at different collection points using wavelength dispersive X-ray fluorescence, investigate the inconstancy of content through analysis of variance, compare the qualitative and quantitative results with the literature and discuss the possibility of inserting the material in the proposal of different authors. Twenty-two oxides and elements were identified; among them, five showed their incidence in a punctual way. The analysis of variance showed that there are significant differences in the concentration of components between batching plants, months and collection points. The comparison with the literature showed that CaO, Al2O3 and SiO2 are the majority, both in the samples under study and in the samples from different authors. However, the average amounts of CaO are higher in the waste sludge from the concrete batching plants in question and, consequently, if this material were reused in the same proposals as the authors, the products would possibly present different characteristics and performance.
{"title":"Statistical Analysis of the Chemical Composition of Concrete Slurry Waste: A Case Study of Sedimentation Tanks from Concrete Batching Plants in Manaus-Brazil","authors":"Jéssica Raíssa Guimarães, Yves Nathan de Faria, Mateus de Oliveira, L. Manzato, Cláudia Silva","doi":"10.21577/0103-5053.20230034","DOIUrl":"https://doi.org/10.21577/0103-5053.20230034","url":null,"abstract":"Concrete slurry waste is a material removed from sedimentation tanks that receive water used to wash concrete mixer trucks and patios of concrete batching plants (CBP). The objectives of this study were to determine the chemical composition of this residue from three different producers, in three consecutive months and at different collection points using wavelength dispersive X-ray fluorescence, investigate the inconstancy of content through analysis of variance, compare the qualitative and quantitative results with the literature and discuss the possibility of inserting the material in the proposal of different authors. Twenty-two oxides and elements were identified; among them, five showed their incidence in a punctual way. The analysis of variance showed that there are significant differences in the concentration of components between batching plants, months and collection points. The comparison with the literature showed that CaO, Al2O3 and SiO2 are the majority, both in the samples under study and in the samples from different authors. However, the average amounts of CaO are higher in the waste sludge from the concrete batching plants in question and, consequently, if this material were reused in the same proposals as the authors, the products would possibly present different characteristics and performance.","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68332868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-25DOI: 10.21577/0103-5053.20230035
Gustavo Monteiro da Silva, I. Ferreira, M. Costa, Rafael Rocha
High water consumption during irrigation is one of the main problems in agriculture. The preparation of a material that prolongs the water retention capacity of the soil is important. This article aimed to prepare superabsorbent hydrogels by the complexation of chitosan (CHI), with high degree of deacetylation (DD), and carboxymethylcellulose (CMC), with high degree of substitution (SD). Different parameters (concentration and polymeric solutions addition order, polysaccharides’ ratio, pH) were studied. Morphology, thermal stability, chemical composition, mechanical strength, and swelling kinetics of hydrogels in water were evaluated. A hydrogel formation mechanism was discussed and proposed. Results showed that most samples prepared at acid pH disintegrated during swelling test. The morphology of the hydrogels varied with the pH. It was obtained superabsorbent hydrogels (swelling > 400%) based on CMC (SD = 2.23) and CHI (DD = 92%), at basic pH, with good compression strength, and applicable as soil conditioner. The best sample was the one prepared with CMC:CHI = 1:2, polymeric solutions 1.5% m/v and pH 8.
{"title":"Physicochemical Properties of Superabsorbent Hydrogels Formed by Polyelectrolytic Complexation of Carboxymethylcellulose-Chitosan at Basic pH","authors":"Gustavo Monteiro da Silva, I. Ferreira, M. Costa, Rafael Rocha","doi":"10.21577/0103-5053.20230035","DOIUrl":"https://doi.org/10.21577/0103-5053.20230035","url":null,"abstract":"High water consumption during irrigation is one of the main problems in agriculture. The preparation of a material that prolongs the water retention capacity of the soil is important. This article aimed to prepare superabsorbent hydrogels by the complexation of chitosan (CHI), with high degree of deacetylation (DD), and carboxymethylcellulose (CMC), with high degree of substitution (SD). Different parameters (concentration and polymeric solutions addition order, polysaccharides’ ratio, pH) were studied. Morphology, thermal stability, chemical composition, mechanical strength, and swelling kinetics of hydrogels in water were evaluated. A hydrogel formation mechanism was discussed and proposed. Results showed that most samples prepared at acid pH disintegrated during swelling test. The morphology of the hydrogels varied with the pH. It was obtained superabsorbent hydrogels (swelling > 400%) based on CMC (SD = 2.23) and CHI (DD = 92%), at basic pH, with good compression strength, and applicable as soil conditioner. The best sample was the one prepared with CMC:CHI = 1:2, polymeric solutions 1.5% m/v and pH 8.","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68332938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-25DOI: 10.21577/0103-5053.20230040
Marianna C. Silva, Vitor Duarte, L. Sallum, G. Cunha, Jean M. F. Custódio, Allen Oliver, J. Peixoto, A. Menezes, H. Napolitano
The Brazilian Cerrado biome is considered one of the 25 hotspots worldwide that contain bioactive compounds due to its great biodiversity; however, the reduction of its native area over time due to the expansion of urbanization and agribusiness may have compromised knowledge of its biological variety. In this context, knowledge about Cerrado species can contribute to its biodiversity preservation. This study aims to describe the isolation, molecular architecture and theoretical calculations of the compound (3S,8S,9S,10R,13R,14S,17R)-17-[(2R,5R)-5-ethyl -6-methylheptan-2-yl]-10,13 dimethyl 2,3,4,7,8,9,11,12,14,15,16,17-dodecahydro1H-cyclopenta[a]phenanthren-3-ol, extracted from the Brazilian Cerrado Miconia burchellii plant. The supramolecular arrangement was described by Hirshfeld surface analysis, demonstrating the intermolecular interactions in the crystalline packing. The structure-property relationship shows the electrostatic potential map analysis, which reveals that the oxygen region is susceptible to electrophilic attack, and the frontier molecular orbital confirmed the kinetic stability of this compound. This study represents another step forward in the knowledge of compounds with pharmacological and medicinal properties extracted from the Cerrado.
{"title":"Molecular Modeling Studies of β-Sitosterol Extract from Miconia burchellii Triana (Melastomataceae) from Brazilian Cerrado","authors":"Marianna C. Silva, Vitor Duarte, L. Sallum, G. Cunha, Jean M. F. Custódio, Allen Oliver, J. Peixoto, A. Menezes, H. Napolitano","doi":"10.21577/0103-5053.20230040","DOIUrl":"https://doi.org/10.21577/0103-5053.20230040","url":null,"abstract":"The Brazilian Cerrado biome is considered one of the 25 hotspots worldwide that contain bioactive compounds due to its great biodiversity; however, the reduction of its native area over time due to the expansion of urbanization and agribusiness may have compromised knowledge of its biological variety. In this context, knowledge about Cerrado species can contribute to its biodiversity preservation. This study aims to describe the isolation, molecular architecture and theoretical calculations of the compound (3S,8S,9S,10R,13R,14S,17R)-17-[(2R,5R)-5-ethyl -6-methylheptan-2-yl]-10,13 dimethyl 2,3,4,7,8,9,11,12,14,15,16,17-dodecahydro1H-cyclopenta[a]phenanthren-3-ol, extracted from the Brazilian Cerrado Miconia burchellii plant. The supramolecular arrangement was described by Hirshfeld surface analysis, demonstrating the intermolecular interactions in the crystalline packing. The structure-property relationship shows the electrostatic potential map analysis, which reveals that the oxygen region is susceptible to electrophilic attack, and the frontier molecular orbital confirmed the kinetic stability of this compound. This study represents another step forward in the knowledge of compounds with pharmacological and medicinal properties extracted from the Cerrado.","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68333541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-24DOI: 10.21577/0103-5053.20230028
Zilacleide Sousa, C. Henriques, V. D. da Silva
The conversion of ethanol into hydrocarbons, particularly into light olefins, was studied over MCM-22 zeolite in their acid form (HMCM-22) and its derived forms obtained by dealumination with oxalic acid (HMCM-22(OA)) and delamination (HITQ-2). The treatment with oxalic acid did not affect zeolite textural properties but reduced the total density and strength of the acid sites. As to the delamination process, HITQ-2 zeolite presented the highest Brunauer, Emmett and Teller (BET) specific area, mesopore volume, and external area, but the microporosity was not affected. This sample showed a lower SiO2/Al2O3 ratio than the precursor HMCM-22, resulting in the highest acid site density but with the predominance of acid sites with weak and intermediate strength. Both dealumination and delamination led to an increase in the number of structural defects in the samples. The comparison of the catalytic performance at 500 ºC showed that despite the differences in the acidic and textural properties of the samples, they were active for ethanol conversion and highly selective for ethylene production. Ethanol conversion, followed by in situ diffuse reflectance spectroscopy (DRIFTS), was also investigated. It showed that, for both samples, the “coke band” intensity was already significant after 1 min of reaction, similar to what was detected for HMCM-22.
{"title":"Ethanol Conversion Catalyzed by MCM-22 and Its Dealuminated and Delaminated Forms","authors":"Zilacleide Sousa, C. Henriques, V. D. da Silva","doi":"10.21577/0103-5053.20230028","DOIUrl":"https://doi.org/10.21577/0103-5053.20230028","url":null,"abstract":"The conversion of ethanol into hydrocarbons, particularly into light olefins, was studied over MCM-22 zeolite in their acid form (HMCM-22) and its derived forms obtained by dealumination with oxalic acid (HMCM-22(OA)) and delamination (HITQ-2). The treatment with oxalic acid did not affect zeolite textural properties but reduced the total density and strength of the acid sites. As to the delamination process, HITQ-2 zeolite presented the highest Brunauer, Emmett and Teller (BET) specific area, mesopore volume, and external area, but the microporosity was not affected. This sample showed a lower SiO2/Al2O3 ratio than the precursor HMCM-22, resulting in the highest acid site density but with the predominance of acid sites with weak and intermediate strength. Both dealumination and delamination led to an increase in the number of structural defects in the samples. The comparison of the catalytic performance at 500 ºC showed that despite the differences in the acidic and textural properties of the samples, they were active for ethanol conversion and highly selective for ethylene production. Ethanol conversion, followed by in situ diffuse reflectance spectroscopy (DRIFTS), was also investigated. It showed that, for both samples, the “coke band” intensity was already significant after 1 min of reaction, similar to what was detected for HMCM-22.","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68332672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-24DOI: 10.21577/0103-5053.20230033
Mariana Marra, M. Ribeiro, R. Muñoz, E. Richter
Losartan potassium and hydrochlorothiazide are often combined in pharmaceutical formulations for the treatment of hypertension. Therefore, the determination of these compounds in a single run is highly desirable for rapid quality control applications. The present study describes an ultra-fast (ca. 85 injections h−1) and environmentally friendly method based on capillary electrophoresis (CE) with capacitively coupled contactless conductivity detection for simultaneous quantification of potassium, losartan and hydrochlorothiazide. Cation (potassium) and anions (losartan and hydrochlorothiazide) were analyzed in a single run using a background electrolyte composed by 10.0 mmol L-1 boric acid (pH = 9.0, adjusted with sodium hydroxide). The limits of detection were 4.0, 3.0 and 10.0 μmol L-1 for potassium, losartan and hydrochlorothiazide, respectively. The proposed method is simple, fast, with minimal waste generation, and accurate (recovery values between 98 and 102%). The results obtained with the CE method were statistically similar (95% confidence level) to those obtained by high-performance liquid chromatography (losartan and hydrochlorothiazide) and flame photometry (potassium).
{"title":"Fast and Environmentally Friendly Method for Simultaneous Determination of Hydrochlorothiazide, Losartan and Potassium by Capillary Electrophoresis with Capacitively Coupled Contactless Conductivity Detection","authors":"Mariana Marra, M. Ribeiro, R. Muñoz, E. Richter","doi":"10.21577/0103-5053.20230033","DOIUrl":"https://doi.org/10.21577/0103-5053.20230033","url":null,"abstract":"Losartan potassium and hydrochlorothiazide are often combined in pharmaceutical formulations for the treatment of hypertension. Therefore, the determination of these compounds in a single run is highly desirable for rapid quality control applications. The present study describes an ultra-fast (ca. 85 injections h−1) and environmentally friendly method based on capillary electrophoresis (CE) with capacitively coupled contactless conductivity detection for simultaneous quantification of potassium, losartan and hydrochlorothiazide. Cation (potassium) and anions (losartan and hydrochlorothiazide) were analyzed in a single run using a background electrolyte composed by 10.0 mmol L-1 boric acid (pH = 9.0, adjusted with sodium hydroxide). The limits of detection were 4.0, 3.0 and 10.0 μmol L-1 for potassium, losartan and hydrochlorothiazide, respectively. The proposed method is simple, fast, with minimal waste generation, and accurate (recovery values between 98 and 102%). The results obtained with the CE method were statistically similar (95% confidence level) to those obtained by high-performance liquid chromatography (losartan and hydrochlorothiazide) and flame photometry (potassium).","PeriodicalId":17257,"journal":{"name":"Journal of the Brazilian Chemical Society","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68332851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-24DOI: 10.21577/0103-5053.20230023
Mariana Rezende, Pedro Gromboni, Patricia Corradini, Almir Sales, Lucia Mascaro
The water treatment sludge (WTS) is a residue composed of organic and inorganic matter in a solid, liquid, and gaseous state that has a variable composition concerning its physical, chemical, and biological characteristics. The irregular disposal of WTS can promote harmful changes to the environment, such as reduction of dissolved oxygen and increase in the concentration of aluminum and other metals in the receiving watercourses. To propose a suitable purpose for this residue, this work evaluated the physical and mechanical properties of the concrete and corrosion resistance of the reinforcement in a cementitious composite using WTS in replacement to the natural sand. A conventional concrete and a conventional mortar were used as a reference and a 3% WTS-content concrete, and a 3% WTS-content mortar were prepared to evaluate the WTS influence in mechanical properties and corrosion resistance. By electrochemical measurements, it was observed that the resistance of the cementitious matrix was not altered by WTS addition. Regarding steel resistance, the WTS may promote a higher susceptibility to frame corrosion, which can be correlated to the lower pH than reference medium (REF). The concrete reinforcement characterization indicates that concretes with WTS can be used as reinforced concrete structure in urban areas.
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