Solvated electron reaction rates in alcohols and water. Solvent effect

1976 ◽  
Vol 98 (22) ◽  
pp. 6825-6830 ◽  
Author(s):  
Gerald L. Bolton ◽  
Gordon R. Freeman
Keyword(s):  
Solvent Effect ◽  
Reaction Rates ◽  
Solvated Electron ◽  
Water Solvent

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.

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.

Kinetic Solvent Effects in Organic Reactions

2017 ◽  
Author(s):  
Belinda Slakman ◽  
Richard West
Keyword(s):  
Solvent Effect ◽  
Reaction Kinetics ◽  
Computational Methods ◽  
High Throughput ◽  
Kinetic Modeling ◽  
Solvent Effects ◽  
Reaction Rates ◽  
Prior Work ◽  
Solvent Phase ◽  
High Throughput Manner

<div> <div> <div> <p>This article reviews prior work studying reaction kinetics in solution, with the goal of using this information to improve detailed kinetic modeling in the solvent phase. Both experimental and computational methods for calculating reaction rates in liquids are reviewed. Previous studies, which used such methods to determine solvent effects, are then analyzed based on reaction family. Many of these studies correlate kinetic solvent effect with one or more solvent parameters or properties of reacting species, but it is not always possible, and investigations are usually done on too few reactions and solvents to truly generalize. From these studies, we present suggestions on how best to use data to generalize solvent effects for many different reaction types in a high throughput manner. </p> </div> </div> </div>

Kinetics of Ion-Pair Effect of Aquation of Bromopentaammine Cobalt(III) Complex in Different Dicarboxylate Media

2011 ◽  
Vol 324 ◽  
pp. 166-169 ◽  
Author(s):  
Farah Zeitouni ◽  
Gehan El-Subruiti ◽  
Ghassan Younes ◽  
Mohammad Amira
Keyword(s):  
Free Energy ◽  
Solvent Effect ◽  
Compensation Effect ◽  
Ion Pairing ◽  
Reaction Rates ◽  
Ion Pair ◽  
Free Energy Of Activation ◽  
Different Types ◽  
Different Temperatures ◽  
Kinetics Of

The rate of aquation of bromopentaammine cobalt(III) ion in the presence of different types of dicarboxylate solutions containing tert-butanol (40% V/V) have been measured spectrophotometrically at different temperatures (30-600°C) in the light of the effects of ion-pairing on reaction rates and mechanism. The thermodynamic and extrathermodynamic parameters of activation have been calculated and discussed in terms of solvent effect on the ion-pair aquation reaction. The free energy of activation ∆Gip* is more or less linearly varied among the studied dicarboxylate ion-pairing ligands indicating the presence of compensation effect between ∆Hip* and ∆Sip*. Comparing the kip values with respect of different buffers at 40% of ter-butanol is introduced.

Solvent effects on the reactivity of solvated electrons with ammonium and nitrate ions in 1-butanol–water solvents

1993 ◽  
Vol 71 (9) ◽  
pp. 1303-1310 ◽  
Author(s):  
Ruzhong Chen ◽  
Gordon R. Freeman
Keyword(s):  
Solvent Effects ◽  
Pure Water ◽  
Reaction Rates ◽  
Dielectric Relaxation Time ◽  
Unusual Behavior ◽  
Solvated Electrons ◽  
Water Solvent ◽  
Electrical Conductances ◽  
Average Size ◽  
Effective Reaction

Values of the rate constants, k2 (106 m3 mol−1 s−1), of solvated electrons,[Formula: see text] with several related salts, in pure water and pure 1-butanol solvents at 298 K are, respectively, as follows: LiNO3, 9.2, 0.19; NH4NO3, 10, 8.3; NH4ClO4, 1.5 × 10−3, 12 in 20 mol% water; LiClO4, 1.0 × 10−4, < 1.0 × 10−4. The value of [Formula: see text] in water solvent is 48 times larger than that in 1-butanol solvent, whereas [Formula: see text] in water is 10−4 times smaller than the value in 1-butanol. This enormous reversal of solvent effects on [Formula: see text] reaction rates is the first observed for ionic reactants. The solvent participates chemically in the [Formula: see text] reaction, and the overall rate constant increases with increasing viscosity and dielectric relaxation time. This unusual behavior is attributed to a greatly increased probability of reaction of an encounter pair with increasing duration of the encounter. Effective reaction radii κRr for [Formula: see text] and [Formula: see text] were estimated with the aid of measured electrical conductances of the salt solutions in all the solvents. Values of κRr are (2–7) × 10−10 m, except for NH4,s+ in 100 and 99 mol% water, which are 2.6 and 2.7 × 10−14 m, respectively. The effective radii of the ions for mutual diffusion increase with increasing butanol content of the solvent, from ~50 pm in water to ~150 pm in 1-butanol, due to the increasing average size of the molecules that solvate the ions.

A Quantitative Investigation of the Ozonolysis Reaction. XVIII. A Kinetic Study of the Ozone Attack on Phenylethylenes

1973 ◽  
Vol 51 (20) ◽  
pp. 3398-3402 ◽  
Author(s):  
H. Henry ◽  
M. Zador ◽  
S. Fliszár
Keyword(s):  
Liquid Phase ◽  
Solvent Effect ◽  
Kinetic Study ◽  
Temperature Effect ◽  
Reaction Rates ◽  
Quantitative Investigation ◽  
Polar Solvents ◽  
Absolute Reaction

Absolute reaction rates for the ozonolysis of phenylethylenes in the liquid phase indicate: (i) a Hammett dependence, with [Formula: see text], for the ring-substituted trans stilbenes, (ii) a solvent effect, whereby the ozone attack is promoted by polar solvents, and (iii) no temperature effect between 15 and 35 °C, thus indicating [Formula: see text].

Switchover of reactions of solvated electrons with nitrate ions and ammonium ions in propanol–water solvents

1993 ◽  
Vol 71 (9) ◽  
pp. 1297-1302 ◽  
Author(s):  
Tae Bum Kang ◽  
Gordon R. Freeman
Keyword(s):  
Rate Constants ◽  
Pure Water ◽  
Reaction Rates ◽  
Binary Solvents ◽  
Ammonium Ions ◽  
Concentrated Solutions ◽  
Solvated Electrons ◽  
Reaction Rate Constants ◽  
Water Solvent ◽  
Arrhenius Temperature

The reaction rate constants of [Formula: see text] with ammonium nitrate (~ 0.1 mol m−3) in 1-propanol-water and 2-propanol–water binary solvents correspond to [Formula: see text] reaction in the water-rich solvents, and to [Formula: see text] reaction in alcohol-rich solvents. The overall rate constant is smaller in solvents with 40–99 mol% water, with a minimum at 70 mol% water. The Arrhenius temperature coefficient is 26 kJ mol−1 in each pure propanol solvent, increases to 29 kJ mol−1 at 40 mol% water, then decreases to 17 kJ mol−1 in pure water solvent. The high reaction rates in the single component solvents, alcohol or water, are limited mainly by solvent processes related to shear viscosity (diffusion) and dielectric relaxation (dipole reorientation). Rate constants reported for concentrated solutions (50–1000 mol m−3) of ammonium and nitrate salts in methanol (Duplâtre and Jonah. J. Phys. Chem. 95, 897 (1991)) have been quantitatively reinterpreted in terms of the ion atmosphere model.

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