Active Silica
Mostrando 13-24 de 91 artigos, teses e dissertações.
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13. Brazilian gorgonians: a source of odoriferous compounds?
Abstract The gorgonian Phyllogorgia dilatata Esper is an octocoral known to be source of biologically active terpenes. In this study, odoriferous compounds present in P. dilatata tissues were investigated, due to their exotic olfactory notes. The search of volatile compounds was performed in a dichloromethane/methanol extract submitted to a silica gel vacuum
Rev. bras. farmacogn.. Publicado em: 2015-12
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14. Comparative study of the characteristics of nano silica - , silica fume - and fly ash - incorporated cement mortars
The structural characteristics of cement mortars, impregnated with nano silica (NS), silica fume (SF) and fly ash (FA), were comparatively studied using Fourier transform infrared spectrometer (FTIR), thermogravimeter-differential thermogravimeter (TG-DTG) and scanning electron microscope (SEM). The mechanical strengths of the specimens were determined at ea
Mat. Res.. Publicado em: 09/05/2014
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15. Estudo de catalisadores de níquel suportados em cinza de casca de arroz na reforma de metano com dióxido de carbono visando a produção de hidrogênio e gás de síntese
Rice husk ash (RHA) is used as a silica source for several purposes, among them to obtain metal catalysts, as was done in this work. The catalysts were characterized by chemisorption, physisorption, thermal analyses (TG, DSC), X-ray diffraction, X-ray fluorescence, temperature-programmed reduction and scanning electron microscopy. The catalysts synthesized w
Quím. Nova. Publicado em: 2014
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16. Characterization and catalytic performance of potassium loaded on rice husk silica and zeolite nay for transesterification of jatropha seed oil
Rice husk silica (RHS) and NaY were used as supports for potassium (K) prepared from acetate buffer (B) and acetate (A) solutions. K loading did not destroy the NaY structure, but it caused a decrease in the surface area; the K species resided in micropores and on the external surface. In contrast, K loading resulted in the collapse and a decrease in the sur
Quím. Nova. Publicado em: 2013
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17. Concretes with red mud coarse aggregates
Red mud (RM) is a mineral waste, residue of the Bayer process used to obtain alumina from bauxite. While the exploration of rolled pebble damages the environment and is much more controlled by the government, the huge RM disposal areas do not stop increasing and polluting soil, rivers and groundwater sources in Amazon. In this work, the material mixtures use
Materials Research. Publicado em: 27/03/2012
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18. Emprego de catalisadores heterogêneos de CaO e SnO2 suportados em cinza de casca de arroz na obtenção de biodiesel
Silica obtained from rice husk after acid leaching and calcination was compared to commercial silica as a catalyst support. CaO and SnO2 catalysts were prepared by impregnation and tested in the transesterification of soybean oil and the esterification of oleic acid. CaO catalysts showed basic character and were the most active for transesterification, where
Química Nova. Publicado em: 2012
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19. Avaliação da imobilização do sal trissódico do ácido 1,8 -dihidróxi-2-(4-sulfofenilazol)-3,6-naftalenodisulfônico (SPADNS) em sílica gel / Evaluation of 2-(4-sulphophenylazo)-1,8-dihydroxy-3,6-napthalene disulphonic acid trisodium salt immobilization at silica gel
Solid phase extraction (SPE) is a kind of procedure for preconcentration and choice of solid phase is very important to develop analytical methods because your selectivity, affinity and retention capacity. The metals preconcentration is very used in environmental samples that have metals such as Pb2+, Cd2+, Ni2+, Al3+ at μg L-1. In that sense, the main
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 18/03/2011
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20. Preparo, caracterização e aplicação de fases estacionárias de poli(dimetilsiloxano-co-metilfenilsiloxano) sorvidas e imobilizadas sobre sílica e sílica zirconizada / Preparation, characterization and application of stationary phases based on poly(dimethylsiloxane-co-methylphenylsiloxane), sorbed and immobilized onto silica and zirconized silica
This work describes the development of new stationary phases (SP) based on poly(dimethylsiloxane-co-methylphenylsiloxane) sorbed and immobilized onto silica and zirconized silica for reversed phase high performance liquid chromatography. The polymer was immobilized by thermal treatment at 140 °C during 6 h, which were the conditions that produced SP with th
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 25/02/2011
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21. Flavonoids and fatty acids of Camellia japonica leaves extract
The ethanol extract from the leaves of Camellia japonica L., Theaceae, showed antiradical potential in the DPPH test using TLC plates (SiO2). Aiming the isolation of active compounds, this extract was partitioned between BuOH:H2O (1:1) and the two obtained phases were also evaluated to detection of antiradical activity. The active BuOH phase was fractionated
Revista Brasileira de Farmacognosia. Publicado em: 29/07/2011
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22. Experimental and theoretical research on catalytic synthesis of thiophene from furan and H2S
The yield of thiophene from furan and H2S was investigated using selected catalyst carriers (alumina, active carbon and silica gel) and active ingredients (silicotungstic, phosphomolybdic and phosphotungstic acids) to obtain the optimized synthesis parameters. The experimental results indicated that the yield of thiophene reached a maximum when the supported
Brazilian Journal of Chemical Engineering. Publicado em: 2011-03
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23. Oligomerização de olefinas leves catalisada por complexos contendo ligantes B-diimina heterogeneizados em sílica
This work describes ¿-diimine ligands synthesis and the corresponding nickel complexes, homogeneous and heterogeneized, its catalytic application in ethylene oligomerization. Initially held the ¿-diimine ligands synthesis with different substituents in the aromatic ring. These ligands were characterized by CHN elemental analysis, IR, UV-Vis and 1H NRM. Fro
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2011
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24. Caracterização de catalisadores usados na oleoquímica
In order to improve the physical-chemical properties of bio oil from castor oil were used as catalysts silica and alumina, both pure and doped. The study showed that products from the catalytic cracking of castor oil have properties more satisfactory, especially when using alumina. This fact can be explained by higher acidity, mesoporous characteristic and s
Publicado em: 2010