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Campos dos Goytacazes, Brazil

Simas N.K.,Federal University of Rio de Janeiro | Dellamora E.D.C.L.,Federal University of Rio de Janeiro | Schripsema J.,Laboratorio Of Ciencias Quimicas | Lage C.L.S.,Instituto Nacional Da Propriedade Intelectual Inpi | And 5 more authors.
Phytochemistry Letters | Year: 2013

Ethanol extract obtained from dried leaves of Acmella oleracea afforded after a liquid/liquid partition procedure a larvicidal hexane fraction (LC 50 = 145.6 ppm) and a non larvicidal dichloromethane one. From the inactive fraction, three amides were identified, two new structures, named deca-6,9-dihydroxy-(2E,7E)-dienoic acid isobutylamide (1), deca-8,9-dihydroxy- (2E,6Z)-dienoic acid isobutylamide (2) and the known nona-2,3-dihydroxy-6,8- diynoic acid 2-phenylethylamide (3). Bioassay-guided chromatographic fractionation of the hexane partition led to the identification of an amide mixture, nona-(2Z)-en-6,8-diynoic acid 2-phenylethylamide (4) and deca-(2Z)-en-6,8-diynoic acid 2-phenylethlylamide (5). This mixture was active against Aedes aegypti larvae at LC50 = 7.6 ppm. Low toxicity of crude extracts and derived fractions on Artemia salina nauplies showed the possibility of using them to control the A. aegypti mosquito larvae. This is the first report on larvicidal activity of acetylenic 2-phenylethylamides and their identification in A. oleracea leaves.Copyright © 2012 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved. Source


Curcio M.S.,Laboratorio Of Ciencias Quimicas | Oliveira M.P.,Laboratorio Of Ciencias Quimicas | Waldman W.R.,Federal University of Sao Carlos | Sanchez B.,CIEMAT | Canela M.C.,Laboratorio Of Ciencias Quimicas
Environmental Science and Pollution Research | Year: 2014

Photocatalysts supported on polymers are not frequently used in heterogeneous photocatalysis because of problems such as wettability and stability that affect photocatalysis conditions. In this work, we used polypropylene as support for TiO2 sol-gel to evaluate its stability and efficiency under UV radiation. We also tested the effect of the thermo-pressing PP/TiO2 system on the photocatalytic efficiency and stability under UV radiation. The films were characterized by scanning electron microscopy (SEM), UV-Vis spectroscopy and X-ray diffraction (XRD). The SEM micrographs showed that the films of TiO2 sol-gel onto PP has approximately 1.0-μm thick and regular surface and the generation of polypropylene nanowires on hot-pressed samples. XRD showed the formation of TiO2 anatase on the surface of the films made by dip-coating. All photocatalysts were tested in decontaminating air-containing gaseous formaldehyde (70 ppmv) presenting degradation of the target compound to the limit of detection. The photocatalysts showed no deactivation during the entire period tested (30 h), and its reuse after washing showed better photocatalytic performance than on first use. The photocatalyst showed the best results were tested for 360 h with no observed deactivation. Aging studies showed that the film of TiO2 causes different effects on the photostability of composites, with stabilizing effect when exposed to most energetic UVC radiation (λmax = 254 nm) and degradative effects when exposed to UVA radiation (λmax = 365 nm). © 2014 Springer-Verlag Berlin Heidelberg. Source


De Souza Lourenco R.E.R.,Laboratorio Of Ciencias Quimicas | Passoni L.C.,Laboratorio Of Ciencias Quimicas | Canela M.C.,Laboratorio Of Ciencias Quimicas
Journal of Molecular Catalysis A: Chemical | Year: 2014

This work examined the use of pure TiO2, pure heteropolyacid (HPA) H5PW10V2O40 and TiO 2 + H5PW10V2O40 catalysts in the photocatalytic decomposition of dimethyl sulfide (DMS) in the gas phase. DMS was irradiated with visible light from an LED (λ > 400 nm), black light UV-A (λ < 400 nm) and visible fluorescent lamp 'daylight' (variable emission in the UV-A and visible range). DMS decomposition reached almost 100% for the system containing the TiO2 + H5PW 10V2O40 mixed catalyst with exposure to visible daylight. This system maintained stable catalytic activity up to 500 min. These results strongly suggest that a positive synergistic effect occurred between TiO2 and HPA when visible daylight was used. © 2014 Elsevier B.V. Source


Curcio M.S.,Laboratorio Of Ciencias Quimicas | Oliveira M.P.,Laboratorio Of Ciencias Quimicas | Waldman W.R.,Laboratorio Of Ciencias Quimicas | Sanchez B.,Laboratorio Of Ciencias Quimicas | Canela M.C.,Laboratorio Of Ciencias Quimicas
Environmental science and pollution research international | Year: 2015

Photocatalysts supported on polymers are not frequently used in heterogeneous photocatalysis because of problems such as wettability and stability that affect photocatalysis conditions. In this work, we used polypropylene as support for TiO2 sol-gel to evaluate its stability and efficiency under UV radiation. We also tested the effect of the thermo-pressing PP/TiO2 system on the photocatalytic efficiency and stability under UV radiation. The films were characterized by scanning electron microscopy (SEM), UV-Vis spectroscopy and X-ray diffraction (XRD). The SEM micrographs showed that the films of TiO2 sol-gel onto PP has approximately 1.0-μm thick and regular surface and the generation of polypropylene nanowires on hot-pressed samples. XRD showed the formation of TiO2 anatase on the surface of the films made by dip-coating. All photocatalysts were tested in decontaminating air-containing gaseous formaldehyde (70 ppmv) presenting degradation of the target compound to the limit of detection. The photocatalysts showed no deactivation during the entire period tested (30 h), and its reuse after washing showed better photocatalytic performance than on first use. The photocatalyst showed the best results were tested for 360 h with no observed deactivation. Aging studies showed that the film of TiO2 causes different effects on the photostability of composites, with stabilizing effect when exposed to most energetic UVC radiation (λmax = 254 nm) and degradative effects when exposed to UVA radiation (λmax = 365 nm). Source

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