Synthesis
Mostrando 13-24 de 36919 artigos, teses e dissertações.
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13. Sustainable and Reusable Sulfonic Acid-Functionalized Task-Specific Ionic Liquid Catalysts for Multicomponent Reactions. A Review
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 an
Journal of the Brazilian Chemical Society. Publicado em: 2022
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14. Biphasic 0.8BaTiO3/0.2Ni(1-x)CoxFe2O4 nanopowders by in situ sol-gel synthesis
Abstract Nanopowders of the 0.8BaTiO3/0.2Ni(1-x)CoxFe2O4 (x=0, 0.25, 0.5, 0.75, and 1) were synthesized by the in situ sol-gel method using poly(acrylic acid) (PAA1800) as a chelating agent. The synthesis developed using PAA1800 ensured the simultaneous crystallization of two phases. The results provided a reliable method for producing biphasic nanopowders i
Cerâmica. Publicado em: 2022
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15. Valorization of Hesperidin from Citrus Residues: Evaluation of Microwave-Assisted Synthesis of Hesperidin-Mg Complex and Their Insecticidal Activity
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: ph
Journal of the Brazilian Chemical Society. Publicado em: 2022
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16. Heteroannulation Reaction of α-Aminoketones for the Efficient Synthesis of 4-Imidazolin-2-ones and 2-Thiones
The hydrogenation of α-oximinoketones in methanol/HCl afforded α-aminoketones, which were applied without purification to the synthesis of 4-imidazolin-2-ones and 2-thiones, including chiral derivatives. The latter two series were obtained in high yields by a heteroannulation reaction of α-aminoketones with isocyanates and isothiocyanates, respectively. A
Journal of the Brazilian Chemical Society. Publicado em: 2022
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17. Supercritical Carbon Dioxide Effect on Lipase-Catalyzed Geranyl Acetate Synthesis
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 wit
Journal of the Brazilian Chemical Society. Publicado em: 2022
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18. Assessment of the strength of recommendation and quality of evidence: GRADE checklist. A descriptive study
ABSTRACT BACKGROUND: Grading of Recommendations Assessment, Development and Evaluation (GRADE) is a tool for assessing evidence produced in synthesis reports. OBJECTIVES: To present the translation into Portuguese of the GRADE checklist, whose original version is in English, and to describe and explain each topic, in order to provide examples to researcher
Sao Paulo Medical Journal. Publicado em: 2022
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19. Efficacy of group cognitive-behavioral therapy in adolescents with obsessive compulsive disorder: a systematic review and meta-analysis
Objective: To evaluate the effectiveness of group cognitive-behavioral therapy (GCBT) for the treatment of adolescents with obsessive compulsive disorder (OCD). Methods: This review was registered in PROSPERO under number CRD42020158475. Five databases (PubMed, Virtual Health Library, Web of Science, Scopus, and PsycINFO) were searched. After applying the i
Brazilian Journal of Psychiatry. Publicado em: 2022
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20. Microstructural characteristics, properties, synthesis and applications of mullite: a review
Abstract Mullite, an intermediate phase of the binary alumina-silica system, is one of the most important phases of ceramic products containing alumina and silica in the initial composition. Its stoichiometry ranges from 3Al2O3.2SiO2 (3:2) to 2Al2O3.SiO2 (2:1) and its crystalline structure is orthorhombic, characterized by the presence of octahedral chains o
Cerâmica. Publicado em: 2022
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21. Biogenic synthesis of silver nanoparticles from thyme extract for functionalization of a bioactive glass produced from rice husk ash
Abstract The rice husk, agro-industrial residue, stands out for having silica, the main oxide former of the bioactive glass. To avoid contamination in this biomaterial, substances with bactericidal properties, like silver can be incorporated. Thus, the objective of this work is the synthesis of silver nanoparticles to functionalize a bioactive glass synthesi
Cerâmica. Publicado em: 2022
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22. Synthesis and Anti-Chikungunya Virus (CHIKV) Activity of Novel 1,4-Naphthoquinone Sulfonamide and Sulfonate Ester Derivatives
Chikungunya virus (CHIKV) is a re-emerging disease caused by an alphavirus of the Togaviridae family. Since its first description in 1952, the disease has spread worldwide, affecting populations in both tropical and temperate countries. To date, there is no licensed vaccine or specific pharmacological treatment. Therefore, there is an increasing urgency in d
Journal of the Brazilian Chemical Society. Publicado em: 2022
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23. Simple and fast process using hydrochloric acid for producing synthetic zinc-rich stevensite
Abstract In the last decades, clays have been used in sectors such as health and cosmetics. This requires products that are increasingly pure and present homogeneous properties, hardly found in natural clays. The use of synthetic clays can be a solution. For this, it is necessary to explore techniques for their production. The main focus of this study was to
Cerâmica. Publicado em: 2022
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24. SYNTHESIS OF TOLUENE DIISOCYANATE URETHANE PREPOLYMER USING CASTOR OIL AND EVALUATION OF MECHANICAL PROPERTIES
This research is the synthesis of urethane prepolymer cast elastomer which had been produced using toluene diisocyanate and castor oil to replace the synthetic polyol, from petroleum origin, and the evaluation of mechanical properties of the polyurethane. The focus was to replace polyol from petroleum to vegetable material looking for renewable resources. Th
Química Nova. Publicado em: 2022