Eutectic
Mostrando 1-12 de 104 artigos, teses e dissertações.
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1. What is new in non-chromatographic flavonoid purification?
Flavonoids are metabolites occurring in all plant tissues and present different biological activities. They occur in a mixture of similar polarity with laborious separation and purification processes, usually furnishing low yields. Semi-preparative chromatographic methods are universally employed procedures for their isolation. This paper discusses the state
Química Nova. Publicado em: 2022
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2. Solventes eutéticos naturais profundos (NADES) no preparo de amostras de rocha fosfática e suplemento mineral para determinação elementar por técnicas de plasma
Natural deep eutectic solvents (NADES) based on xylitol, citric acid, and malic acid were synthesized and used in ultrasound-assisted extraction (UAE) and heating-bath extraction of phosphate rock and mineral supplement samples. Arsenic, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, P and Zn were determined by inductively coupled plasma mass spectrometry (ICP-MS) and i
Quím. Nova. Publicado em: 2021-06
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3. Astaxanthin Recovery from Shrimp Residue by Solvent Ethanol Extraction Using Choline Chloride:Glycerol Deep Eutectic Solvent as Adjuvant
The present study investigated the use of choline chloride:glycerol deep eutectic solvent as an adjuvant for tuning the ethanol extraction of astaxanthin from Litopenaeus vannamei processing residues. The adjuvant concentration did not show a clear trend on the total carotenoid, however, the addition of adjuvant proved to be advantageous in the ultrasound-as
J. Braz. Chem. Soc.. Publicado em: 2021-05
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4. Spectrophotometric Determination of Allura Red AC and Tartrazine in Food Products Using Hydrophobic Deep Eutectic Solvents as an Environmentally Sustainable Micro-Extractor
This paper reports the application of hydrophobic deep eutectic solvents (HDES) as an environmentally friendly alternative for liquid-phase microextraction (LPME) of Allura Red AC and Tartrazine in food products and the spectrophotometric determination of these analytes. The HDES used in this work were prepared by mixing octanoic acid (OctAc) or decanoic aci
J. Braz. Chem. Soc.. Publicado em: 2021-03
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5. Structure-Physical Properties Relationship of Eutectic Solvents Prepared from Benzyltriethylammonium Chloride and Carboxylic Acids
Deep eutectic solvents (DESs) have attracted the attention of the researchers as alternative solvents due to desirable properties such as easy preparation and high thermal stability. In this work, it was reported the preparation of five DESs from benzyltriethylammonium chloride (BTEAC) as quaternary ammonium salt (QAS) and carboxylic acids (oxalic, malonic o
J. Braz. Chem. Soc.. Publicado em: 2021-03
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6. Preparation of a New Polymeric Deep Eutectic Solvent and Its Application in Vortex-Assisted Liquid-Liquid Microextraction of Parabens in Foods, Cosmetics and Pharmaceutical Products
A vortex-assisted liquid-liquid microextraction method combined with high performance liquid chromatography-diode array detector has been developed for the determination of parabens in foods, cosmetics and pharmaceutical products. In this work, polymeric deep eutectic solvents composed of DL-menthol and polyethylene glycol with three different light grades w
J. Braz. Chem. Soc.. Publicado em: 2020-10
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7. A Choline Chloride-Ethylene Glycol Deep Eutectic Solvent Based on Magnetic Polydopamine with Preconcentration and Determination for Sulfonylurea Herbicides in Water Samples
In this study, a novel deep eutectic solvent (DES) containing choline chloride and ethylene glycol was synthesized, and the magnetic polydopamine (PDA) was modified with this deep eutectic solvent to form Fe3O4@PDA-DES. Fourier transformed infrared spectroscopy, scanning electron microscopy, and vibrating sample magnetometer were used to characterize the pro
J. Braz. Chem. Soc.. Publicado em: 2020-07
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8. Effect of Welding Parameters on Nanostructured Fe-(C, B)-(Cr, Nb) Alloys
New nanostructured Fe-(Nb,Cr)-(C,B) multicomponent alloys have been developed for hardfacing application. They have better wear resistance than traditional Fe-Cr-C alloys. The nano-alpha-Fe, eutectic and hard carboborides phases of the weld metal usually show variations with the welding procedure. 6 test samples with different heat input were welded. It was
Mat. Res.. Publicado em: 20/01/2020
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9. DEEP EUTECTIC SOLVENTS BASED ON BETAINE AND PROPYLENE GLYCOL AS POTENTIAL DENITRIFICATION AGENTS: A LIQUID-LIQUID EQUILIBRIUM STUDY
Abstract Two deep eutectic solvents (DES) based on betaine (B) and propylene glycol (PG) in molar ratios of 1:4 and 1:5 were prepared and their physico-chemical properties were determined. Liquid-liquid equilibria at 298.15 K and atmospheric pressure were determined for 13 quasi-three-component systems with a hydrocarbon (n-hexane, n-heptane, i-octane or tol
Braz. J. Chem. Eng.. Publicado em: 13/01/2020
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10. Tensile and fatigue properties, machinability and machined surface roughness of Al-Si-Cu alloys
ABSTRACT In this paper, the aim was to determine if ASC91 (9 % Al, 1 % Cu) could be replaced with ASC73 (7 % Al, 3 % Cu) aluminium alloy, with presumably improved machinability due to lower silicon content (9 to 7 %) and retained mechanical properties due to a higher copper content (1 to 3 %). The test samples were excised from cylinder heads produced by the
Matéria (Rio J.). Publicado em: 16/09/2019
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11. Effects of Macrosegregation and Microstructure on the Corrosion Resistance and Hardness of a Directionally Solidified Zn-5.0wt.%Mg Alloy
This study aims to analyze the influence of macrosegregation on microstructure evolution, and of microstructure length scale on the corrosion resistance of a Zn-5.0wt.%Mg alloy casting. The analyzed samples were taken along the length of castings unidirectionally solidified in unsteady state conditions of heat extraction. Microstructure characterization, mic
Mat. Res.. Publicado em: 05/09/2019
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12. Effect of Extrusion and Heat Treatment on Microstructure and Mechanical Properties of Hypereutectic A390-0.3wt%Nd Alloy
An hypereutectic aluminium alloy with a composition of 16-18wt%Si, 4-5wt%Cu, 0.45-0.65wt%Mg, 0.3wt%Nd and Al balance (A390-0.3wt%Nd alloy) was processed by extrusion and aging at 200ºC for 10 hours. The effect of the thermomechanical processing and heat treatment on microstructure and mechanical properties was investigated for A390-0.3wt%Nd alloy. It was sh
Mat. Res.. Publicado em: 10/06/2019