Results 191 to 200 of about 10,994 (228)

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

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

SET-LRP of 2-hydroxyethyl acrylate in protic and dipolar aprotic solvents

Polymer Chemistry, 2013
Cu(0) wire-mediated single-electron transfer living radical polymerization (SET-LRP) of 2-hydroxyethyl acrylate (HEA) was performed in protic solvents, MeOH, binary mixtures of MeOH and EtOH with H2O, and H2O, and in the dipolar aprotic solvent, DMSO.
Leng, X.; Nguyen, N. H. van Beusekom, Wilson, D.A., Percec, V.   +6 more
openaire   +1 more source

Photolysis of acetyl esters of 2,2′-dinitrodiphenyl-carbinols in protic and aprotic solvents

Research on Chemical Intermediates, 1991
Irradiation 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
openaire   +1 more source

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

Structural and conformational differences of acylated hyaluronan modified in protic and aprotic solvent system

Carbohydrate Polymers, 2012
Acylated hyaluronan (HA) in aqueous (DMSO/H2O) and nonaqueous (DMSO) solutions was studied by means of nuclear magnetic resonance, differential scanning calorimetry (DSC), mass spectrometry and UV/vis spectroscopy. It has been demonstrated that structural and conformational properties of the acylated hyaluronan derivates are strongly dependent on the ...
Daniela Šmejkalová, Martina Hermannová, Romana Šuláková, Alena Průšová, Jiří Kučerík, Vladimír Velebný   +5 more
openaire   +1 more source

Rates of Bimolecular Substitution Reactions in Protic and Dipolar Aprotic Solvents

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
openaire   +1 more source

Initial state and transition state solvent effects: Reactions in protic and dipolar aprotic media

Inorganica Chimica Acta, 1980
This work is concerned with the origin of effects on rate equilibrium processes when reactions are performed in dipolar aprotic media such as dimethyl sulfoxide and dimethyl-formamide compared to typical hydroxylic media. An example of processes studied in our laboratory is the competition between proton abstraction and σ-complex (Meisenheimer adduct ...
openaire   +1 more source

Replacement of Less-Preferred Dipolar Aprotic and Ethereal Solvents in Synthetic Organic Chemistry with More Sustainable Alternatives

Chemical Reviews, 2022
Andrew Jordan, Callum G.J. Hall, Helen F Sneddon   +2 more
exaly  

Kinetic study of phenol nitrosation in protic and aprotic solvents

Materials Chemistry, 1982
S. Pérez G., G. Pieza R., E. Vázquez F., C. Pérez G.   +3 more
openaire   +1 more source