Effects of dielectric permittivity and viscosity on diffusion-controlled solvated electron + solute reactions in alcohol/water mixed solvents

1988 ◽  
Vol 92 (6) ◽  
pp. 1506-1510 ◽  
Author(s):  
Yadollah Maham ◽  
Gordon R. Freeman
Keyword(s):  
Dielectric Permittivity ◽  
Mixed Solvents ◽  
Solvated Electron ◽  
Diffusion Controlled ◽  
Alcohol Water

Solvent structure effects on solvated electron reactions with ions in 2-butanol/water mixed solvents

1991 ◽  
Vol 69 (5) ◽  
pp. 884-892 ◽  
Author(s):  
Sedigallage A. Peiris ◽  
Gordon R. Freeman
Keyword(s):  
Rate Constant ◽  
Pure Water ◽  
Mixed Solvents ◽  
Reaction Rates ◽  
Bimolecular Reaction ◽  
Activation Energies ◽  
Solvated Electron ◽  
Polar Species ◽  
Water Solvent ◽  
Alcohol Water

The Smoluchowski–Debye–Stokes–Einstein equation for the rate constant k2 of a bimolecular reaction between charged or polar species[Formula: see text]was used to evaluate effects of bulk solvent properties on reaction rates of solvated electrons with [Formula: see text] and [Formula: see text] in 2-butanol/water mixed solvents. To explain detailed effects it was necessary to consider more specific behavior of the solvent. Rate constants k2, activation energies E2, and pre-exponential factors A2 of these reactions vary with the composition of 2-butanol/water mixtures. The values of E2 were in general similar to activation energies of ionic conductance EΛ0 of the solutions, except for much higher values of E2 of [Formula: see text] in alcohol-rich solvents and of [Formula: see text] in pure water solvent. The solvent apparently participates chemically in the [Formula: see text] reaction, and the [Formula: see text] reaction is multistep. Rate constant and conductance measurements of thallium acetate solutions in 2-butanol containing zero and 10 mol% water were complicated by the formation of ion clusters larger than pairs. Key words: alcohol/water mixed solvents, ions, reaction kinetics, solvated kinetics, solvated electron, solvent effects.

Article

1998 ◽  
Vol 76 (4) ◽  
pp. 407-410
Author(s):  
Yixing Zhao ◽  
Gordon R Freeman
Keyword(s):  
Pure Water ◽  
Mixed Solvents ◽  
Molar Conductivity ◽  
Solvated Electron ◽  
Pure Ethanol ◽  
Electrical Conductances ◽  
Alcohol Water ◽  
Different Temperatures ◽  
Ion Radius ◽  
Pure Methanol

As a foundation for a future measurement of solvated electron mobilities in alcohol-water mixed solvents, the electrical conductances of sodium tetraphenylboride (STPB) in methanol-water, ethanol-water, and 2-propanol-water were measured at different temperatures. The molar conductivity LAMBDA 0 (10-4 S m2 mol-1) of STPB at 298 K is 70 in pure water and 82 in pure methanol; in methanol-water mixed solvents it passes through a minimum, the value being 45 at 70 mol% water. In 2-propanol-water LAMBDA 0 (10-4 S m2 mol-1) at 298 K decreases rapidly from 70 in pure water to 22.6 in 80 mol% water, then gradually to 16.5 in pure 2-propanol. Behavior in ethanol-water is intermediate, with a minimum of 29.5 in 70 mol% water, gradually increasing to 35.5 in pure ethanol. The product of LAMBDA 0 and the solvent viscosity eta has a maximum at about 75 mol% water in methanol, 90 mol% water in ethanol, and 95 mol% water in 2-propanol. The effects are attributed to changes of solvent structure and of solvated ion radius as alcohol is added to water.Key words: alcohol-water mixed solvents, electrical conductivity, large ions, solvent effects, activation energy.

Solvent structure effects on solvated electron reactions in mixed solvents: positive ions in 1-propanol/water and 2-propanol/water

1991 ◽  
Vol 69 (1) ◽  
pp. 157-166 ◽  
Author(s):  
Sedigallage A. Peiris ◽  
Gordon R. Freeman
Keyword(s):  
Pure Water ◽  
Mixed Solvents ◽  
Reaction Rates ◽  
Mutual Diffusion ◽  
Residual Effects ◽  
Solvated Electron ◽  
Bulk Fluid ◽  
Positive Ions ◽  
Water Solvent ◽  
Alcohol Water

In models of the kinetics of chemical reactions in solution the solvent is commonly assumed to be a uniform continuum. An example is the Smoluchowski–Debye–Stokes–Einstein equation for the rate constant k2 of a bimolecular reaction between charged or polar species:[Formula: see text]where κ is the probability that a reactant encounter pair will react, R is the gas constant, T is the temperature, f is a factor that reflects the effect of electrostatic interaction between the reactants on their probability of attaining the closeness of approach rr at which reaction occurs, η is the solvent viscosity, and rd is the effective radius of the reactant entities for mutual diffusion. The equation is useful in evaluating effects of bulk fluid properties on reaction rates. Residual effects are attributed to more specific solvent behaviour.Rate constants k2, activation energies E2, and pre-exponential factors A2 of reactions of solvated electrons [Formula: see text] with [Formula: see text] [Formula: see text] and [Formula: see text] ions vary with the composition of 1-propanol/water and 2-propanol/water mixed solvents. Plots of k2η/fT against solvent composition are nonlinear and change with the solvent pair and with reactant pair. Measured molar conductivities [Formula: see text] [Formula: see text] [Formula: see text] and [Formula: see text] indicate that the values of rd for the mutual diffusion of the cations and anions have a minimum near 90 mol% water, and that the values in pure propanol-1 or −2 (150–190 pm) are larger than those in pure water solvent (26 pm for [Formula: see text] 70 pm for the metal ions). The liquid structure influences both the rate of diffusion and the probability of reaction of a reactant encounter pair. Key words: alcohol/water mixed solvents, positive ions, reaction kinetics, solvated electron, solvent effects.

Inclusion Behavior of Chemical Modified β-cyclodextrin in Alcohol/Water Mixed Solvents

2000 ◽  
Vol 16 (03) ◽  
pp. 248-252
Author(s):  
Jie Hong-Zhi ◽  
◽  
Wu Shi-Kang
Keyword(s):  
Mixed Solvents ◽  
Alcohol Water

Erratum: Solvent structure effects on solvated electron reactions in mixed solvents: Negative ions in 1-propanol–water and 2-propanol–water

1992 ◽  
Vol 70 (2-3) ◽  
pp. 192-192
Author(s):  
Annesley Peiris Sedigallage ◽  
Gordon R. Freeman
Keyword(s):  
Mixed Solvents ◽  
Negative Ions ◽  
Solvent Structure ◽  
Solvated Electron

Solvent effect on the dissociation of p-nitroanilinium ion in glycerol–water media at 25 °C

1984 ◽  
Vol 62 (11) ◽  
pp. 2245-2248
Author(s):  
Amrita Lal De ◽  
Tapas Kumar De
Keyword(s):  
Solvent Effect ◽  
Dissociation Constants ◽  
Mixed Solvents ◽  
Individual Species ◽  
Aqueous Mixtures ◽  
Free Energies ◽  
Monohydric Alcohol ◽  
Glycerol Water ◽  
Alcohol Water ◽  
The Individual

Thermodynamic dissociation constants (sK) of p-nitroanilinium ion (BH+) have been determined at 25 °C in aqueous mixtures of 10, 30, 50, 70, and 90 wt.% of glycerol (GL) by spectrophotometric measurements. Standard free energies, [Formula: see text], of p-nitroaniline (B) from water to mixed solvents have been evaluated from the measurement of solubilities at 25 °C. p(sK) values decrease with increase in mol% of GL and pass through a minimum and then increase very slowly. The solvent effect on the dissociation, δ(ΔG0) = 2.303RT [p(sK)N – p(wK)N] has been discussed in terms of the standard free energies of transfer [Formula: see text] from water to aqueous mixtures of GL of the uncharged base (B), the hydrochloride of the base (BHCl), hydrochloric acid (HCl), and also in terms of the individual species involved in the dissociation process. The solvent effect in trihydric alcohol – water (GL + H2O) system has been compared with those in dihydric alcohol – water (ethylene glycol + water) and monohydric alcohol – water (ethanol + water) systems available from literature. The much less solvent effect in GL + H2O has been primarily attributed to the contrasting nature of interaction of H+ and of partially charged H atoms of—NH3+ group in BH+ compared to those in other two solvent systems.

Studies in mixed solvents: Comparison between solvated electron reactions and quenching of excited states

1995 ◽  
Vol 27 (6) ◽  
pp. 535-545 ◽  
Author(s):  
Sudhir Kumar Kapoor ◽  
C. Gopinathan
Keyword(s):  
Excited States ◽  
Mixed Solvents ◽  
Solvated Electron

CCCLIV.—The velocity of reaction in mixed solvents. Part VII. The influence of the base on the velocity of saponification of esters in methyl alcohol-water mixtures

1924 ◽  
Vol 125 (0) ◽  
pp. 2590-2595 ◽  
Author(s):  
Walter Idris Jones ◽  
Hamilton McCombie ◽  
Harold Archibald Scarborough
Keyword(s):  
Methyl Alcohol ◽  
Mixed Solvents ◽  
Alcohol Water
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