Solvent
Mostrando 13-24 de 2730 artigos, teses e dissertações.
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13. Evaluation of the Structural Integrity of Layered Double Hydroxides and Mesoporous Silica During the Preparation of Heterostructures
Heterostructures constructed with mesoporous silica and layered double hydroxides are interesting for catalytic and drug delivery applications. Different arrangements between these phases are possible. In this study, we prepared heterostructures by embedding layered double hydroxides phases [M4Al2(OH)12](CO3) (M = Mg2+ or Zn2+) within the MCM41 mesoporous si
Journal of the Brazilian Chemical Society. Publicado em: 2022
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14. CLOROFILA EXTRAÍDA DE RESÍDUO INDUSTRIAL DA ERVA-MATE (Ilex paraguaiensis) UMA POSSIBILIDADE DE ECONOMIA CIRCULAR
Chlorophyll is the most abundant green pigment on the planet, it is unstable and decomposes naturally. Mate-herb is a traditional native plant in the southern region of South America, and its tea is part of the local culture and extractive agriculture. The mate-herb industry generates as a by-product a resinous material rich in chlorophyll whose use is propo
Química Nova. Publicado em: 2022
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15. Eco-friendly multivariant green analytical technique for the estimation of ketoconazole by UV spectroscopy in bulk and cream formulation
The pharmaceutical industries are focusing on Green Analytical Chemistry principles like miniaturization, eco-friendly solvent usage, waste recycling, and analyst safety for sustainable results. A simple, eco-friendly sensitive and effective extraction and multivariant green analytical method to estimate ketoconazole in bulk and cream formulation were develo
Química Nova. Publicado em: 2022
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16. Pretreatment and Enzymatic Saccharification of Water Hyacinth, Sugarcane Bagasse, Maize Straw, and Green Coconut Shell Using an Organosolv Method with Glycerol and FeCl3
A method to pretreatment of biomasses using glycerol as a green solvent was developed. Optimization of organosolv pretreatment was performed using a 23 factorial design, investigating synergism among the variables particle size (from < 0.85 to > 2.0 mm), FeCl3 concentration (0.025-0.175 mol L-1), and temperature (160-220 °C). Although the effects of the var
Journal of the Brazilian Chemical Society. Publicado em: 2022
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17. Use of Direct Aqueous Injection and Solid Phase Extraction Coupled with Hydrophilic Interaction Chromatography to Analyze Haloacetic Acids in Drinking Water Samples
In this study, two analytical methods were evaluated to determine haloacetic acids (HAAs) in drinking water samples. Direct aqueous injection (DAI) and solid phase extraction (SPE) were evaluated and determination was performed by liquid chromatography tandem mass spectrometry (LC-MS/MS) with a hydrophilic interaction chromatography (HILIC) analytical column
Journal of the Brazilian Chemical Society. Publicado em: 2022
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18. 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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19. Processamento de catalisadores gastos de unidade de hidrodessulfurização profunda (ultra-deep HDS)
PROCESSING OF SPENT ULTRA-DEEP HYDRODESULFURIZATION CATALYSTS. This work discusses the recycling of spent NiMo/Al2O3 catalysts from ultra-deep hydrodesulfurization (HDS) units. They contain a refractory coke and fouling elements from the processed feedstocks. Samples were preoxidized (600 ºC) for 12 h using a very slow heating rate to eliminate coke and vol
Química Nova. Publicado em: 2022
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20. Extraction and Characterization of Pequi Seed Oil for Biodiesel Production: A Green Management of Waste to Biofuel Using Ethanol and Heterogeneous Catalysis
This work reports the characterization of a vegetable oil extracted from pequi seeds, an agroindustrial residue, and its biodiesel production using ethanol and heterogeneous catalysis. The pequi seeds showed 40.73 wt.% of extractive content, which represents a large amount of the biomass composition. The crude oil extracted from the pequi seeds with ethanol
Journal of the Brazilian Chemical Society. Publicado em: 2022
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21. Optimization of ultrasound-assisted extraction of turkish propolis and characterization of phenolic profile, antioxidant and antimicrobial activity
Abstract This study aimed to determine optimum conditions of the ultrasound assited extraction (UAS) parameters for different solvent types by using response surface methodology (RSM) and Box- Behnken design. The model parameters namely, time, temperature and ultrasound power significantly affected TPC value of the propolis extract (P < 0.05). The optimum pr
Food Sci. Technol. Publicado em: 2021-09
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22. Assessment of sensory and physical-chemical quality, and potential for certification of cachaças from the state of Paraíba, Brazil
Abstract The State of Paraíba is an important producer of artisanal cachaça that has outstanding quality in national tasting panels and for this reason this research studied organizational aspects for certification and compliance with Good Manufacturing Practices - GMP - of 53% of formal producers. Samples of cachaças from these producers were evaluated f
Food Sci. Technol. Publicado em: 2021-09
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23. Elemental Chalcogen (Se, S) in PEG-400 to the Synthesis of Seleno- and Thioflavones from 2-Chlorophenyl Ethynyl Ketone and Nucleophilic Species of Chalcogen
An alternative green method was developed for the synthesis of thio-and selenoflavones by the ring closure of 2-chlorophenyl ethynyl ketone with NaHY (Y = S, Se). These nucleophilic chalcogen species were generated in situ using NaBH4 to reduce the elemental chalcogen in the presence of polyethylene glycol-400 (PEG-400). The efficiency of this reaction is st
J. Braz. Chem. Soc.. Publicado em: 2021-08
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24. Extraction optimization and antioxidant activity of Phyllanthus urinaria polysaccharides
Abstract Three extraction parameters including extraction time, material to solvent ratio, and extraction temperature for the extraction yield of Phyllanthus urinaria polysaccharides were optimized by response surface methodology. The results revealed that the optimal extraction process was extraction time of 5.3 h, extraction temperature of 93 °C, and mate
Food Sci. Technol. Publicado em: 2021-06