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 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.

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.

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.

CONDUCTANCES OF LITHIUM NITRATE SOLUTIONS IN ETHYL ALCOHOL AND ETHYL ALCOHOL - WATER MIXTURES AT 25.0 °C.

1956 ◽  
Vol 34 (9) ◽  
pp. 1232-1242 ◽  
Author(s):  
A. N. Campbell ◽  
G. H. Debus
Keyword(s):  
No Value ◽  
Ethyl Alcohol ◽  
Pure Water ◽  
Lithium Ion ◽  
Water Molecules ◽  
Lithium Nitrate ◽  
Absolute Alcohol ◽  
Pure Alcohol ◽  
Alcohol Water ◽  
Nitrate Solutions

The conductances of solutions of lithium nitrate in 30, 70, and 100 weight per cent ethyl alcohol have been determined at concentrations ranging from 0.01 molar up to saturation, at 25 °C. The densities and viscosities of these solutions have also been determined. The data have been compared with the calculated conductances obtained from the Wishaw–Stokes equation. The agreement is fairly good up to, say, 2 M, for all solvents except absolute alcohol. In the latter solvent there is no value of å, the distance of closest approach, which will give consistent values of the equivalent conductance. In passing from pure water to pure alcohol, the value of å increases progressively and this we attribute to a change in the solvation of the lithium ion from water molecules to alcohol molecules. Some further calculations incline us to the view that the nitrate ion, as well as the lithium ion, is solvated to some extent, at least in alcohol.

Densities, electrical conductances, and spectroscopic properties of glycyl dipeptide+ionic liquid ([C12mim]Br)+water mixtures at different temperatures

2014 ◽  
Vol 367 ◽  
pp. 125-134 ◽  
Author(s):  
Zhenning Yan ◽  
Rui Geng ◽  
Bixin Gu ◽  
Qi Pan ◽  
Jianji Wang
Keyword(s):  
Ionic Liquid ◽  
Spectroscopic Properties ◽  
Electrical Conductances ◽  
Different Temperatures ◽  
Glycyl Dipeptide

scholarly journals The Effect Of Hydrazine Addition On The Formation Of Oxygen Molecule By Fast Neutron Radiolysis

KnE Energy ◽  
2016 ◽  
Vol 1 (1) ◽  
Author(s):  
G.R. Sunaryo
Keyword(s):  
Room Temperature ◽  
Pure Water ◽  
Water System ◽  
Calculation Model ◽  
High Dose ◽  
Primary Coolant ◽  
Batch System ◽  
Different Temperatures ◽  
Oxygenated Water ◽  
Deaerated Condition

<p>Hypothetically speaking, hydrazine could suppress the oxygen formation as a major of corrosion initiator. In this work, we developed a calculation model to understand the effect of hydrazine addition toward the oxygen under PWR condition. Our great interest is to study whether this strategy would also be effectively applied in PWRs<a href="file:///C:/Users/Mohamad%20Mostafa/Desktop/Knowledge%20E/In%20Press%20Conferences/ICoNETS-2015/Source-Manuscripts/20_L05-Geni_p136-141.docx#_msocom_1">[P1]</a> . In the present work, the effect of hydrazine on suppressing the molecule oxygen under neutron irradiation is described.  The simulation was done by using FACSIMILE.  The variation dose applied assuming a batch system and at high dose ~10<sup>4</sup> Gy s<sup>-1</sup>.  Three different temperatures were applied, which are room temperature, 250 and 300 <sup>o</sup>C at two system oxygenated water, which are aeration and deaeration. At room temperature, for deaerated condition, added hydrazine under a range of 10<sup>-6</sup> – 10<sup>-4</sup> M into primary coolant were not effective to suppress  O<sub>2 </sub>form since the effect was similar as in the pure water system since for 10<sup>-3</sup> M hydrazine addition, a large produce of O<sub>2 </sub>were obtained. In reverse, for deaerated condition, hydrazine concentrate about 10<sup>-3</sup> M can suppress O<sub>2</sub> form significantly, while hydrazine add in the range between 10<sup>-6</sup> – 10<sup>-4</sup> M is again confirmed to be the same as in pure water system. For high temperature, at 250 and 300 <sup>o</sup>C, the results showed that in deaerated condition, hydrazine addition can suppress  O<sub>2  </sub>form<sub> </sub>proportionally to its concentration while in aerated condition, hydrazine add with concentration of 10<sup>-6</sup> and 10<sup>-5</sup> M were not effectively to suppress O<sub>2  </sub>form,<sub> </sub>a slightly decrease of O<sub>2</sub> occurred due to the addition of 10<sup>-4</sup> M hydrazine and 10<sup>-3</sup> M of hydrazine can suppress the formation of O<sub>2</sub> significantly. <a href="file:///C:/Users/Mohamad%20Mostafa/Desktop/Knowledge%20E/In%20Press%20Conferences/ICoNETS-2015/Source-Manuscripts/20_L05-Geni_p136-141.docx#_msocom_2">[P2]</a> </p><div><hr align="left" size="1" width="33%" /><div><div><p> <a href="file:///C:/Users/Mohamad%20Mostafa/Desktop/Knowledge%20E/In%20Press%20Conferences/ICoNETS-2015/Source-Manuscripts/20_L05-Geni_p136-141.docx#_msoanchor_1">[P1]</a>The added sentence</p><p> </p></div></div><div><div><p> <a href="file:///C:/Users/Mohamad%20Mostafa/Desktop/Knowledge%20E/In%20Press%20Conferences/ICoNETS-2015/Source-Manuscripts/20_L05-Geni_p136-141.docx#_msoanchor_2">[P2]</a>The revised sentence</p></div></div></div>

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
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