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Mostrando 1-12 de 7879 artigos, teses e dissertações.
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1. Bimetallic Au-Pd/α-MoO3 Catalyst with High Oxygen Vacancies for Selective Oxidation of Cinnamyl Alcohol
Supported Au-Pd nanoparticles (NPs) have been extensively studied in alcohol oxidation reactions. However, few studies use reducible metal oxides as support, which can activate oxygen molecules and boost the selectivity of the reaction. In this work, Au-Pd NPs were supported on α-MoO3 and evaluated in the selective oxidation of cinnamyl alcohol without solv
Journal of the Brazilian Chemical Society. Publicado em: 2023
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2. Catalysts Derived from Thermal Treatments of Hydrocalumite-Type Compounds: Synthesis and Application in Transesterification Reactions
Catalyst performance is a relevant factor in biodiesel production because it can affect the efficiency of the process. This work provides a study of the performance of heterogeneous catalysts for biodiesel production derived from thermal-treated hydrocalumite-type compounds. This work aimed to synthesize and characterize hydrocalumite-type compounds intercal
Journal of the Brazilian Chemical Society. Publicado em: 2023
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3. Novel Greener Microwave-Assisted Deprotection Methodology for the 1,3-Dioxolane Ketal of Isatin Using Calix[n]arenes
In this work, the combined use of p-sulfonic acid-calix[n]arene and microwave energy to hydrolyze the 1,3-dioxolane ketal of isatin was evaluated with excellent results. This is the first time that p-sulfonic acid-calix[n]arene has been used as the catalyst in a ketal hydrolysis reaction and the deprotection of the ketone carbonyl of isatin is reported. The
Journal of the Brazilian Chemical Society. Publicado em: 2022
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4. Metal-Supported Niobium Catalysts Investigation for Conversion of Bio-Renewable Glycerol to Organic Compounds
The glycerol oxidative dehydration to organic compounds, especially acrolein and acrylic acid, was studied over vanadium, molybdenum, and cobalt oxides supported on niobium oxide and niobium phosphate catalysts. At 300 °C, the glycerol conversion was 100% over all catalysts tested, and acrolein was the main product observed, without significant deactivation
Journal of the Brazilian Chemical Society. Publicado em: 2022
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5. K2O SUPORTADO EM ZEÓLITA NATURAL: SÍNTESE, CARACTERIZAÇÃO E APLICAÇÃO PRODUÇÃO DE BIODIESEL A PARTIR DO ÓLEO DE GIRASSOL
Biodiesel is a renewable fuel, a substitute for fossil diesel, which is important for reducing GHG in Brazil. Therefore, this work aims to synthesize and characterize the catalyst using the support of natural zeolite impregnated with K2O and apply it in the production of biodiesel through the transesterification reaction. Through the analysis of characteriza
Química Nova. Publicado em: 2022
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6. Diesel-Like Biofuels Production Using Fatty Waste
According to the waste-to-energy (WTE) valorization and circular economy principles, the use of waste oil and grease (WOG) for obtaining biofuels shows the tendency towards sustainability, makes the interest in green chemistry, and the development of environmentally friendly processes grow. Three different fatty wastes (from the fat trap of a sewage station,
Journal of the Brazilian Chemical Society. Publicado em: 2022
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7. 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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8. PLANEJAMENTO FATORIAL NA SÍNTESE DO OLEATO DE ETILA CATALISADA PELA LIPASE NATIVA DE Aspergillus niger
This work reports the use of the Octave, a free computational software, to optimize the experimental design in the synthesis of ethyl oleate from oleic acid and ethanol catalyzed by a native lipase from Aspergillus niger. The central composite factorial design (CCD) was performed with 2 levels and 3 variables (temperature, mass of native A. niger lipase and
Química Nova. Publicado em: 2022
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9. Capital, Agency and Distinction in Dynamics of Conversion of Economic Functions of Cities: Lessons from Lafayette (US)
RESUMO A transição para a sociedade digital tem atraído a atenção de grupo crescente de estudiosos que buscam investigar limitações dessa nova etapa das forças produtivas nas intervenções urbanas. Desse contexto surge a motivação para este artigo, o qual visa analisar resultados de levantamento empírico de dados realizado na cidade norte-america
BBR. Brazilian Business Review. Publicado em: 2022
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10. AMORPHOUS CUSEP2/GRAPHENE COMPOSITES AS ANODE MATERIAL FOR ADVANCED POTASSIUM-ION BATTERY
The ternary amorphous CuSeP2 was designed and prepared as the anode material of potassium ion battery for the first time, and its electrochemical performance was also investigated. After ball-milling with commercial graphene powder, it is used as the anode material for potassium ion battery with reversible specific capacity up to 300 mAh g-1, and the corresp
Química Nova. Publicado em: 2022
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11. Diagnostic approach in a patient with Creutzfeldt-Jakob disease
RESUMO As doenças priônicas são uma importante causa de demências rapidamente progressivas. Entre elas, a mais comum é a doença de Creutzfeldt-Jakob (DCJ) esporádica. É uma enfermidade rara e incurável, com rápida progressão para óbito. Objetivo: Descrever a abordagem diagnóstica de uma paciente com doença de Creutzfeldt-Jakob. Métodos: O di
Dementia & Neuropsychologia. Publicado em: 2022
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12. Simultaneous Quantification of Amorphous and Crystalline Valsartan in Tablets Using Raman Spectroscopy and Chemometrics Tools
Valsartan is an antihypertensive active pharmaceutical ingredient (API), it is used in the amorphous state in the commercial products. As amorphous materials are metastable, amorphous valsartan can crystallize to valsartan E, promoting changes in the dissolution and bioavailability of the drug. Tablets containing metastable forms of APIs need special conditi
Journal of the Brazilian Chemical Society. Publicado em: 2022