Results 131 to 140 of about 1,561 (166)
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Isotropic magnetic shielding constants of retinal derivatives in aprotic and protic solvents
The Journal of Chemical Physics, 2013We investigate the nuclear isotropic shielding constants σ(13C) and σ(17O) of isomers of retinoic acid and retinal in gas-phase and in chloroform, acetonitrile, methanol, and water solutions via Monte Carlo simulation and quantum mechanics calculations using the GIAO-B3LYP/6-311++G(2d,2p) approach.
G, Colherinhas +4 more
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DPPH assay of vegetable oils and model antioxidants in protic and aprotic solvents
Talanta, 2013The rate of reaction of phenolic antioxidants with DPPH depends on solvent composition. The rate constants can differ by more than two orders of magnitude for the same phenolic compound. Reactions are faster in alcohols than in ethyl acetate that is used routinely for the analysis of antioxidant potential (AOP) of nonpolar samples such as vegetable ...
Tjaša, Prevc +3 more
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Diffusion of symmetrical and spherical solutes in protic, aprotic, and hydrocarbon solvents
Journal of Solution Chemistry, 1979The diffusion coefficients of a series of symmetrical tetraalkyltins (tetramethyltin, tetraethyltin, tetrapropyltin, tetrabutyltin, tetradodecyltin) of the gases argon, krypton, xenon, methane, and tetramethylmethane and of carbon tetrachloride and tetraethylmethane in hexane, decane, and tetradecane at 25°C have been determined using the Taylor ...
D. Fennell Evans +2 more
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Solvent effect on nonradiative process of pyronin B in protic and aprotic solvent systems
Journal of Luminescence, 2002Abstract Absorption and emission spectra of pyronin B were taken in acetonitrile and acetonitrile-benzene solvent mixtures. Fluorescence lifetime (τf) and quantum yield (Φf) were determined as a function of temperature and nonradiative rate constant (knr) was calculated from τf and Φf.
ARIK, M, ACEMIOGLU, B, Onganer, Yavuz
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Dipolar aprotic–protic solvent influences in the hydrolysis of diol monoesters
International Journal of Chemical Kinetics, 1974AbstractThe kinetics of the alkaline hydrolysis of five diol monoesters and related esters in aqueous DMSO, aqueous acetone, and aqueous ethanol are reported. A novel solvent dependency of the reactivity pattern of the various esters is noticed.
M. Balakrishnan +2 more
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Spectroscopic studies of the solvation of carbon dioxide in protic and aprotic solvents
Journal of Molecular Liquids, 1990The asymmetric C=0 stretching band (υ 3 ) for dilute solutions of carbon dioxide in a range of protic and aprotic solvents has been measured. Relative to «inert» solvents such as cyclohexane and tetrachloromethane, both classes of solvent induce high frequency ...
Graham Eaton, Martyn C.R. Symons
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Photophysical Properties of Coumarin-30 Dye in Aprotic and Protic Solvents of Varying Polarities¶
Photochemistry and Photobiology, 2004ABSTRACTExperimental results on various photophysical properties of coumarin‐30 (C30) dye, namely, Stokes' shift (Δv), fluorescence quantum yield (τf), fluorescence lifetime (τf), radiative rate constant (kf) and nonradiative rate constant (knr), as obtained using absorption and fluorescence measurements have been reported.
Sadasivam, Senthilkumar +2 more
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Canadian Journal of Chemistry, 1986
Rate constants of acid-catalyzed hydrolysis of sucrose (S) to D-glucose and L-fructose have been determined at 25 °C by optical rotation measurements in aqueous mixtures of protophobic protic glycerol (GL), protophilic protic urea (UH), aprotic dioxane (D), and dipolar aprotic dimethyl sulphoxide (DMSO). Transfer free energies of the substrate sucrose,
Urmila Mandal +2 more
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Rate constants of acid-catalyzed hydrolysis of sucrose (S) to D-glucose and L-fructose have been determined at 25 °C by optical rotation measurements in aqueous mixtures of protophobic protic glycerol (GL), protophilic protic urea (UH), aprotic dioxane (D), and dipolar aprotic dimethyl sulphoxide (DMSO). Transfer free energies of the substrate sucrose,
Urmila Mandal +2 more
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Photolysis of acetyl esters of 2,2′-dinitrodiphenyl-carbinols in protic and aprotic solvents
Research on Chemical Intermediates, 1991Irradiation ofacetyl esters of 2,2′-dinitrodiphenyl-carbinols (1a-d) in aprotic medium like 2-propanol yielded dibenzol [c,f]-[1,2]diazepin-11-one-5-oxides (5a-d) as the major product. Dibenzoi[c,f]-[1,2]diazepin-11-one (2a-d), 2,2′-dinitrobenzophenones (3a-d), 2-amino-2′-nitrobenzophenones (4a-d), and N-hydroxyacridones (6a-d) were also formed in ...
T. Mathew, C. P. Joshua
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Coloration Technology, 2003
The electrochemical and photochemical reduction in ethanol of a series of azobenzene dyes containing tertiary amine groups has been investigated. It has been shown that the two mechanisms are of parallel importance and an explanation suggested using quantum chemical calculations (AM1, DFT).
R Podsiadły +5 more
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The electrochemical and photochemical reduction in ethanol of a series of azobenzene dyes containing tertiary amine groups has been investigated. It has been shown that the two mechanisms are of parallel importance and an explanation suggested using quantum chemical calculations (AM1, DFT).
R Podsiadły +5 more
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