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

1990 ◽  
Vol 68 (9) ◽  
pp. 940-946 ◽  
Author(s):  
Annesley Peiris Sedigallage ◽  
Gordon R. Freeman
Keyword(s):  
Mixed Solvents ◽  
Negative Ions ◽  
Liquid Structure ◽  
Reaction Rates ◽  
Effective Radius ◽  
Mutual Diffusion ◽  
Residual Effects ◽  
Coulombic Interaction ◽  
Bulk Fluid ◽  
Interaction Factor

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: k2 = κRTfrr/1.5ηrd where κ = probability that a reactant encounter pair will react, R = gas constant, T = temperature, f = Coulombic interaction factor, rr = effective radius for reaction, η = solvent viscosity, and rd = effective radius 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 and activation energies E2 of reactions of solvated electrons [Formula: see text] with [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 solvent pair and with reactant pair. Measured molar conductivities Λ0(Li+, [Formula: see text]) and Λ0(2Li+, [Formula: see text]) indicate the solvent dependence of rd for the mutual diffusion of Li+ and [Formula: see text] or [Formula: see text]. The liquid structure influences both the rate of diffusion of the reactants and the probability of reaction of a reactant encounter pair.

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

Thermodynamics of transfer of p-nitroaniline from water to alcohol + water mixtures at 25 °C and the structure of water in these media

1977 ◽  
Vol 55 (23) ◽  
pp. 3961-3966 ◽  
Author(s):  
Kumardev Bose ◽  
Kiron K. Kundu
Keyword(s):  
Mixed Solvents ◽  
Solvent Structure ◽  
Free Energies ◽  
Solvent Interactions ◽  
Structure Of Water ◽  
Thermodynamics Of Transfer ◽  
Alcohol Water ◽  
Composition Profiles

Free energies (ΔGt0) and entropies (ΔSt0) of transfer at 25 °C of the nonelectrolyte p-nitroaniline from water to various alcohol + water mixtures have been determined from solubility measurements at seven temperatures from 10–40 °C. Increasing specific solute–solvent interactions have been proposed to interpret the nature of the ΔGt0-composition profiles and the enhanced structure of water in the water-rich mixed solvents has been correlated with maxima in the ΔSt0-composition profiles. The effectiveness of p-nitroaniline as a useful probe for studying solvent structure has been pointed out.

scholarly journals Optical absorption spectra of solvated electrons in 1-butylamine–water mixed solvents

1995 ◽  
Vol 73 (12) ◽  
pp. 2126-2130 ◽  
Author(s):  
Yixing Zhao ◽  
Gordon R. Freeman
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Pure Water ◽  
Mixed Solvents ◽  
Binary Solvents ◽  
Optical Absorption Spectra ◽  
Solvated Electron ◽  
Solvated Electrons ◽  
Selective Solvation ◽  
Ideal Mixing

The optical absorption spectra of es− in 1-butylamine–water mixed solvents increase smoothly in energy and intensity as the water content is increased, with the exception of a small decrease in intensity on going from 95 to 100 mol% water. At 298 K the value of Gεmax increases from 1.42 × 10−21 m2/16 aJ (8.6 × 103 es−L/100 eV mol cm) in pure 1-butylamine to 8.3 × 10−21 m2/16 aJ (50 × 103 es−L/100 eV mol cm) in pure water, and the value of EAmax increases from 115 zJ (0.72 eV) to 278 zJ (1.74 eV). In the pure amine, if G(es−) = 0.27, then εmax = 5.3 × 10−21 m2/es− (3200 m2/mol). The solvent composition dependences of Gεmax and EAmax indicate little selective solvation of es− by water; this might be due to relatively "ideal" mixing of water and amine in the binary solvents. The temperature coefficient −dEAmax/dT = 0.43 zJ/K in pure 1-butylamine, 0.47 in pure water, and has a minimum of 0.27 in the 50:50 mixture. Keywords: 1-butylamine–water mixed solvents, optical absorption spectra, solvated electron, temperature dependence.

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.

Effects of solvent structure on electron reactivity and radiolysis yields: 2-propanol/water mixed solvents

1984 ◽  
Vol 62 (7) ◽  
pp. 1265-1270 ◽  
Author(s):  
Joanna Cygler ◽  
Gordon R. Freeman
Keyword(s):  
Pure Water ◽  
Mixed Solvents ◽  
Water Structure ◽  
Trap Depth ◽  
Solvent Structure ◽  
Solvated Electrons ◽  
Absorption Energy ◽  
Diffusion Controlled ◽  
Free Ion ◽  
Different Temperatures

Reaction of solvated electrons with nitrobenzene, N, is nearly diffusion controlled in both pure solvents; kN ~ 1010 dm3/mol s. The value of kN is approximately proportional to the inverse viscosity η−1 in the pure solvents, and in the mixed solvents at different temperatures. However, on going from zero to 74 mol% water at the same temperature kN is independent of the 40% increase of η. Electron diffusion in the mixed solvents is not a simple function of fluidity.Reaction with the inefficient scavengers tryptophane (kS ~ 109 dm3/mol s) and phenol (kS ~ 107–108 dm3/mol s) correlates inversely with the electron optical absorption energy. The latter is related to the trap depth in the solvent; electrons in deeper traps have less tendency to react with molecules of low electron affinity.Addition of 3 mol% 2-PrOH to water at 296 K increases the value of Gεmax by 16%, although the value in pure 2-PrOH is three-fold smaller than that in pure water. The increase is attributed to an increase in the free ion yield, caused by an increase in the product of the electron thermalization range and the microscopic dielectric constant of the fluid between the ion and electron, averaged over the time that they exist as a correlated pair. Addition of a small amount of alcohol to water increases the orderliness of the water structure.

Solvolysis rates in aqueous–organic mixed solvents. IX. Solvolysis of dichloroacetate ion in water–methanol solutions

1981 ◽  
Vol 59 (8) ◽  
pp. 1208-1211 ◽  
Author(s):  
El-Hussieny M. Diefallah ◽  
Mohamed A. Ashy ◽  
Ahmed O. Baghlaf
Keyword(s):  
Mole Fraction ◽  
Reaction Rate ◽  
Mixed Solvents ◽  
Activation Parameters ◽  
Solvent Structure ◽  
Temperature Range ◽  
Methanol Solutions ◽  
Aqueous Organic Mixed Solvents ◽  
Kinetics Of ◽  
Influence Of Solvent

The kinetics of the alkaline solvolysis of dichloroacetate ion in water–methanol solutions have been studied in the temperature range of 50.0 to 65.0 °C and the influence of solvent variation on reaction rate has been examined in terms of changes in the activation parameters. The activation parameters ΔH≠ and ΔS≠ for the solvolysis reaction showed a minimum at about 0.8 water mole fraction. The significance of the results was discussed in view of the electrostatic theory and the changing of solvent structure.

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