Results 181 to 190 of about 4,840 (219)

Rates of Bimolecular Substitution Reactions in Protic and Dipolar Aprotic Solvents

Advances in Physical Organic Chemistry, 1967
Publisher Summary Bimolecular reactions between anions and polar molecules are very much faster in dipolar aprotic solvents than in protic solvents. This simple observation has led to a reassessment of the chemistry of those rate and equilibrium processes that involve anions in solution. Comparison of rates of S N 2 reactions in protic and in dipolar
A J Parker
exaly   +2 more sources

DPPH assay of vegetable oils and model antioxidants in protic and aprotic solvents

Talanta, 2013
The 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, Nataša, Segatin, Nataša Poklar, Ulrih, Blaž, Cigić   +3 more
openaire   +2 more sources

Diffusion of symmetrical and spherical solutes in protic, aprotic, and hydrocarbon solvents

Journal of Solution Chemistry, 1979
The 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, Toshihiro Tominaga, C. Chan   +2 more
openaire   +1 more source

Solvent effect on nonradiative process of pyronin B in protic and aprotic solvent systems

Journal of Luminescence, 2002
Abstract 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
openaire   +2 more sources

Entering chloride kinetic isotope effects in protic and aprotic solvents

Journal of the American Chemical Society, 1976
Chlorine kinetic isotope effects for the reaction of ethylene oxide and chloride ion are normal (/sup 35/Cl//sup 37/Cl greater than unity) in protic solvents and in acetone and dimethylformamide (DMF) in the presence of 1 equiv of 2,6-lutidinium ion. In the presence of 0.1 equiv of this cation (and 0.9 of Li/sup +/) the isotope effect in DMF is inverse
Thomas H. Cromartie, C. Gardner Swain
openaire   +1 more source

Dipolar aprotic–protic solvent influences in the hydrolysis of diol monoesters

International Journal of Chemical Kinetics, 1974
AbstractThe 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, G. Venkoba Rao, N. Venkatasubramanian   +2 more
openaire   +1 more source

On the chemiluminescence emission of luminol: protic and aprotic solvents and encapsulation to improve the properties in aqueous solution

Physical Chemistry Chemical Physics, 2020
Luminol encapsulation increases the chemiluminescence wavelength and emission intensity for non-invasive cancer treatments.
Ana Borrego-Sánchez, Angelo Giussani, Mercedes Rubio, Daniel Roca-Sanjuán   +3 more
openaire   +3 more sources

Spectroscopic studies of the solvation of carbon dioxide in protic and aprotic solvents

Journal of Molecular Liquids, 1990
The 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
openaire   +1 more source

Photophysical Properties of Coumarin-30 Dye in Aprotic and Protic Solvents of Varying Polarities¶

Photochemistry and Photobiology, 2004
ABSTRACTExperimental 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, Sukhendu, Nath, Haridas, Pal   +2 more
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Kinetic solvent effects on acid-catalyzed hydrolysis of sucrose in aqueous mixtures of some protic, aprotic, and dipolar aprotic solvents

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, Kaushik Das, Kiron Kumar Kundu   +2 more
openaire   +1 more source