Solvation
Mostrando 13-24 de 198 artigos, teses e dissertações.
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13. Fast Screening of Solvents for Simultaneous Extraction of Furfural, 5-Hydroxymethylfurfural and Levulinic Acid from Aqueous Solution Using SMD Solvation Free Energies
Acid catalyzed decomposition of C5 and C6 sugars has been considered an important source of biomass derived chemicals. An essential step in this process is the extraction of furfural, hydroxymethylfurfural and levulinic acid from aqueous phase. In this work, a computational screening of 178 organic solvents for simultaneous extraction of these chemicals from
J. Braz. Chem. Soc.. Publicado em: 2018-02
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14. Effect of Acetonitrile and N,N-Dimethylformamide on the Formation of Poly(ethylene oxide)-Sodium Alkyl Sulfate Aggregates
The effects of low contents of acetonitrile (AN) or N,N-dimethylformamide (DMF) on the aggregation of sodium alkyl sulfate surfactants, in the absence and presence of poly(ethylene oxide) (PEO), were investigated using conductivity and isothermal titration calorimetry. The cosolvents slightly changed the critical micellar concentrations and did not alter the
J. Braz. Chem. Soc.. Publicado em: 2018-01
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15. Liquid-liquid extraction equilibrium for pyruvic acid recovery: experimental data and modeling
ABSTRACT Physical extraction studies of pyruvic acid from dilute aqueous solutions (0.025 kmol·m-3 to 0.200 kmol·m-3) using several pure solvents (tri-n-butylphosphate (TBP), 1-decanol, 1-octanol, toluene, Methyl-isobutylketone (MIBK), and n-heptane) and their binary mixtures are reported in this work. All the batch extraction experiments were carried out
Braz. J. Chem. Eng.. Publicado em: 2017-07
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16. SYNERGIC EXTRACTION OF PANTOTHENIC ACID WITH TWO DIFFERENT EXTRACTANTS
Abstract The influences of extractants concentrations and solvent polarity on the efficiency of pantothenic acid separation by synergic extraction with tri-n-octylamine (TOA) and di(2-ethylhexyl) phosphoric acid (D2EHPA) mixture have been analyzed. The results indicated the formation of an interfacial compound which includes one molecule of pantothenic acid
Braz. J. Chem. Eng.. Publicado em: 2016-12
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17. FASES ESTACIONÁRIAS DE LÍQUIDOS IÔNICOS EM CROMATOGRAFIA GASOSA: FUNDAMENTOS, AVANÇOS RECENTES E PERSPECTIVAS
Since their original discovery in 1914, ionic liquids (IL) have been widely examined and explored in chemistry due to their unique physical and chemical properties. Ionic liquids are collectively known as organic salts and have melting points of 100 °C or under. The molten salts most employed in analytical chemistry, including gas chromatography (GC), consi
Quím. Nova. Publicado em: 2016-01
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18. Prediction of Phase Separation Using a Modified Regular Solution Theory and the SMD Continuum Solvation Model
It is proposed a new expression for the β parameter in the regular solution theory, using the solvation free energy concept instead of the solubility parameter. This modified regular solution theory can be applied for any liquid mixture combined with any method for solvation free energy calculation. The new approach was tested in fifteen liquid mixtures
J. Braz. Chem. Soc.. Publicado em: 2015-08
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19. Preparation and properties of perichromic dye: an undergraduate laboratory
An undergraduate experiment that illustrates the phenomenon of perichromism-the sensitivity of a dye to its microenvironment, as assessed by color changes of its solutions-is described. An easily prepared perichromic imine is synthesized and characterized, and its solvatochromism, thermochromism, halochromism, and preferential solvation in binary solvent mix
Quím. Nova. Publicado em: 2014
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20. Propriedades relacionadas à acidez e basicidade a partir da abordagem em química computacional
Analytical Chemistry books lack a clear link between thermodynamic and equilibrium approaches involving acids and bases. In this work, theoretical calculations were performed to search for these relations. An excellent relationship was found between difference in Gibbs free energy, ∆G of acid dissociation reaction and ∆G of hydrolysis reaction of the cor
Quím. Nova. Publicado em: 2014
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21. Aplicação da técnica de elipsometria de emissão para caracterização de materiais luminescentes
In this work we demonstrated the potential of the emission ellipsometry in the scope of the Stokes theory for electromagnetic field to the photophysics study of luminescent materials, in addition we introduce a new methodology using an achromatic quarter-wave plate. Moreover, the use of linearly polarized light allowed "selectively" the study of various phot
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/02/2012
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22. Estimating reaction constants by ab initio molecular modeling: a study on the oxidation of phenol to catechol and hydroquinone in advanced oxidation processes
Molecular modeling is growing as a research tool in Chemical Engineering studies, as can be seen by a simple research on the latest publications in the field. Molecular investigations retrieve information on properties often accessible only by expensive and time-consuming experimental techniques, such as those involved in the study of radical-based chain rea
Brazilian Journal of Chemical Engineering. Publicado em: 2012-03
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23. Síntese e propriedades de líquidos iônicos e tensoativos / Synthesis and properties of ionic liquids and surfactants
O trabalho desenvolvido teve como objetivo estudar a solvatação em misturas binárias de água com líquidos iônicos, LIs, destacando a influência da lipofilicidade e estrutura deste últimos. Além disso, estudou-se uma série inédita de líquidos iônicos tensoativos, LITs, cujas propriedades em solução aquosa, foram determinadas através de diversa
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 18/11/2011
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24. Aplicação das relações lineares de energia livre de solvatação (LSER) ao estudo de sistemas interfaciais organizados / Application of linear solvation energy relationships (LSER) to the study of organized interfacial systems
Neste estudo foi caracterizado o processo de solubilização de solutos neutros em sistemas micelares compostos de surfactantes não iônicos da família de alcoóis secundários etoxilados com o mesmo grupo hidrofóbico e graus diferentes de etoxilação, variando de 5 a 30 subunidades de oxido de etileno. Para isso, foram utilizadas as Relações Lineares
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/10/2011