Methanol
Mostrando 1-12 de 1780 artigos, teses e dissertações.
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1. 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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2. 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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3. 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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4. A New Approach for Histamine Functionalized Nanoparticles as Sorbent Phase for Bar Adsorptive Microextraction (BAµE) and Determination of Parabens in Water by HPLC-DAD
In this study, for the first time, histamine-functionalized magnetic nanoparticles (HIS-MNP) were used as sorbent phase combined with bar adsorptive microextraction (BAµE) for the determination of methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP) in water samples by high performance liquid chromatography coupled with diode arr
Journal of the Brazilian Chemical Society. Publicado em: 2022
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5. METABOLIC PROFILING AND CYTOTOXIC ACTIVITY OF METHANOL EXTRACTS FROM CHAMAECRISTA DUCKEANA (P. BEZERRA & A. FERN.) H. S. IRWIN & BARNEBY (LEGUMINOSAE, CAESALPINIOIDEAE)
The genus Chamaecrista comprises more than 330 species, with only a few studies on their chemical composition and biologic activities. In this study, the phytochemical profile of leaf, stems, and fruits extracts of the C. duckeana were examined by UPLC ESI HRMS analysis to determine possibly bioactive constituents. The antioxidant activity was carried out th
Química Nova. Publicado em: 2022
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6. Wine composition of Merlot and Cabernet Sauvignon vine clones under the environmental conditions of Serra Gaúcha, Brazil
Abstract This study aimed to evaluate the wine composition from vine clones of Merlot (181, 346, 347, 348) and Cabernet Sauvignon (R5, 18A, 163, 338, 341). The grapes were harvested between 2010 and 2012, then on the same day, taken to the winery facility for winemaking. After crushing and destemming the grapes, the musts were transferred to glass containers
Food Sci. Technol. Publicado em: 2021-06
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7. Porosity of CHA Zeolite Driving the Formation of Polyaromatic Coke Species in the Methanol to Olefins Reaction
The pore size of the chabazite structure is exceptionally suitable for the methanol to olefins (MTO) reaction. The reaction has an induction period required for the formation of a hydrocarbon pool (HP), usually composed of aromatic compounds of different sizes. HP is alkylated by methanol and afterward cracked, leading to the formation of olefins. Despite th
J. Braz. Chem. Soc.. Publicado em: 2021-05
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8. Chemical Constituents and Cytotoxic Activity of Rhinella jimi (Anura: Bufonidae)
Rhinella jimi toads (Stevaux, 2002) belong to the Bufonidae family, are endemic in the Brazilian Northeast and are commonly found during rainy periods. In general, amphibians of this family have in their poisons different metabolites that show a diversity of pharmacological activities. The isolation and identification of these compounds are of great importan
J. Braz. Chem. Soc.. Publicado em: 2021-05
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9. MODIFICAÇÃO QUÍMICA DO POLIPROPILENO ATRAVÉS DA INTRODUÇÃO DE GRUPOS SULFÔNICOS PARA APLICAÇÃO COMO CATALISADOR EM REAÇÕES DE ESTERIFICAÇÃO
In this work, the chemical modification of pristine polypropylene was carried out through sulfonation reactions with concentrated sulfuric acid (PPS1) and fuming sulfuric acid (PPS2), for production of heterogeneous catalysts used in esterification reactions. Fourier transform infrared spectroscopy, elemental analysis, degree of substitution and ion exchange
Quím. Nova. Publicado em: 2021-04
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10. Thermal and Catalytic Fast Pyrolysis of Oily Extracts of Microalgae: Production of Biokerosene
Three different microalgae species, Desmodesmus sp., Nannochloropsis oculata and Halamphora coffeaeformis were grown under controlled conditions. The resulting dry biomass was characterized by TG-DTA (thermogravimetry-differential thermal analysis) and extracted with three solvents having different polarities. The extracts gross mass yields varied from 2% us
J. Braz. Chem. Soc.. Publicado em: 2021-04
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11. Reduced Graphene Oxide-Cadmium Sulfide Quantum Dots Nanocomposite Based Dispersive Solid Phase Microextraction for Ultra-Trace Determination of Carbamazepine and Phenobarbital
This research presents a fast, sensitive, and selective ultrasound-assisted dispersive solid phase microextraction technique for simultaneous preconcentration and determination of ultra-trace amount of carbamazepine and phenobarbital. Reduced graphene oxide sheets decorated with cadmium sulfide quantum dots was synthesized, characterized, and used as a high
J. Braz. Chem. Soc.. Publicado em: 2021-04
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12. HSCCC Separations of Rutin Esters Obtained by Enzymatic Reaction Catalyzed by Lipase
The flavonoid rutin presents several pharmacological effects, despite this, its application in the pharmaceutical industry can be significantly limited by its low bioavailability. The development of lipophilic derivatives by esterification of hydroxyl groups with fatty acid chains may be an effective strategy to change their physicochemical properties. This
J. Braz. Chem. Soc.. Publicado em: 2021-03