A pulse radiolysis study of solvated electrons in tert-butanol/water solutions

1986 ◽  
Vol 64 (8) ◽  
pp. 1548-1552
Author(s):  
Joanna Cygler ◽  
Norman V. Klassen ◽  
Carl K. Ross
Keyword(s):  
Experimental Data ◽  
Pulse Radiolysis ◽  
Oh Radicals ◽  
Solvated Electrons ◽  
Secondary Electrons ◽  
Water Solutions ◽  
Tert Butanol

Many solutes, added to water in amounts of a few mol%, cause an increase in the yield of solvated electrons (es−) measured by pulse radiolysis. A pulse radiolysis study of tert-butanol (tBuOH) in D2O has been carried out to investigate this phenomenon. Detailed measurements of the yield, measured as Gεmax(es−), and the deeay of solvated electrons were made at 6, 25, and 46 °C over the range 0–5mol% tBuOH. The maximum Gεmax(es−) occurs at about 1 mol% tBuOH, but the exact concentration depends on the temperature of the sample and the time after the pulse at which the measurement is made. Three factors are examined as contributing to the increased Gεmax(es−) in the presence of tBuOH and certain other solutes. They are (i) the change in viscosity produced by the added solute, (ii) the scavenging of OH radicals by the solute, thereby reducing the reaction of OH with es− and (iii) the possibility that the addition of the solute leads to an increase in the thermalization distance of the secondary electrons. It is concluded that effects (i) and (ii) are sufficient to explain the existing experimental data.

A pulse radiolysis study of solvated electrons in dilute solutions of polar liquids in nonpolar solvents

1977 ◽  
Vol 55 (11) ◽  
pp. 1996-2002 ◽  
Author(s):  
J. H. Baxendale
Keyword(s):  
Absorption Spectra ◽  
Pulse Radiolysis ◽  
Electron Pulse ◽  
Pulse Irradiation ◽  
Dilute Solutions ◽  
Solvated Electrons ◽  
Polar Liquids ◽  
Tert Butanol ◽  
Nonpolar Solvents ◽  
Existence Of Equilibria

Measurements of the conductivities following electron pulse irradiation of dilute solutions of ethanol, n-propanol, tert-butanol, or dimethyl sulphoxide in n-hexane, cyclohexane, or i-octane are quantitatively consistent with the existence of equilibria between electrons in the hydrocarbon and electrons solvated by dimers of the polar molecules. With dimethylformamide solutions in alkanes the equilibrium could be with the monomeric anion of the solute but this assignment is not unequivocal. Absorption spectra of es− in n-hexane solutions of ethanol and of tert-butanol have been obtained.

Photoredox Reactions of Iodo Iron(III) Complexes Containing Tetradentate Ligands

2001 ◽  
Vol 66 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Jozef Šima ◽  
Dáša Lauková ◽  
Vlasta Brezová
Keyword(s):  
Schiff Bases ◽  
Spin Trapping ◽  
Molar Ratio ◽  
Oh Radicals ◽  
Solvated Electrons ◽  
Open Chain ◽  
Tetradentate Ligands ◽  
Visible Irradiation ◽  
Epr Spin Trapping ◽  
Spin Trapping Technique

Photoredox reactions occurring in irradiated methanolic solutions of trans-[FeIII(R,R'-salen)(CH3OH)I], where R,R'-salen2- are N,N'-ethylenebis(R,R'-salicylideneiminato), tetradentate open-chain N2O2-Schiff bases with R,R' = H, 5-Cl, 5-Br, 3,5-di-Br, 3,5-di-(CH3), 3-OCH3, 5-OCH3, have been investigated and their mechanism proposed. The complexes are redox-stable in the dark. Ultraviolet and/or visible irradiation of methanolic solution of the complexes induces photoreduction of Fe(III) to Fe(II). Depending on the composition of the irradiated solutions, •CH2OH radicals or solvated electrons were identified by the EPR spin trapping technique. The final product of the photooxidation coupled with the photoreduction of Fe(III) is formaldehyde and the molar ratio of Fe(II) and CH2O is close to 2 : 1. The efficiency of the photoredox process is strongly wavelength-dependent and influenced by the peripheral groups R,R' of the tetradentate ligands.

Reactions of OH radicals with tris(1,10-phenanthroline)iron(II) studied by pulse radiolysis

1976 ◽  
Vol 8 (4) ◽  
pp. 425-426 ◽  
Author(s):  
E. Siekierska Floryan ◽  
P. Pagsberg
Keyword(s):  
Pulse Radiolysis ◽  
Oh Radicals

Article

1998 ◽  
Vol 76 (4) ◽  
pp. 411-413
Author(s):  
Yixing Zhao ◽  
Gordon R Freeman
Keyword(s):  
Absorption Spectrum ◽  
Optical Absorption ◽  
Temperature Dependence ◽  
Optical Absorption Spectrum ◽  
Infrared Light ◽  
Solvated Electron ◽  
Solvated Electrons ◽  
Tert Butanol ◽  
Solvent Dependence ◽  
Increasing Temperature

The energy and asymmetry of the optical absorption spectrum of solvated electrons, es- , change in a nonlinear fashion on changing the solvent through the series HOH, CH3OH, CH3CH3OH, (CH3)2CHOH, (CH3)3COH. The ultimate, quantum-statistical mechanical, interpretation of solvated electron spectra is needed to describe the solvent dependence. The previously reported optical spectrum of es- in tert-butanol was somewhat inaccurate, due to a small amount of water in the alcohol and to limitations of the infrared light detector. The present note records the remeasured spectrum and its temperature dependence. The value of the energy at the absorption maximum (EAmax) is 155 zJ (0.97 eV) at 299 K and 112 zJ (0.70 eV) at 338 K; the corresponding values of G epsilon max (10-22 m2 aJ-1) are 1.06 and 0.74. These unusually large changes are attributed to the abnormally rapid decrease of dielectric permittivity of tert-butanol with increasing temperature. The band asymmetry at 299 K is Wb/Wr = 1.8.Key words: optical absorption spectrum, solvated electron, solvent effects, tert-butanol, temperature dependence.

ChemInform Abstract: Oxidation of Tryptophan and N-Methylindole by N× 3, Br×- 2, and (SCN)×- 2 Radicals in Light- and Heavy-Water Solutions: A Pulse Radiolysis Study.

ChemInform ◽  
2010 ◽  
Vol 22 (34) ◽  
pp. no-no
Author(s):  
S. SOLAR ◽  
N. GETOFF ◽  
P. S. SURDHAR ◽  
D. A. ARMSTRONG ◽  
A. SINGH
Keyword(s):  
Heavy Water ◽  
Pulse Radiolysis ◽  
Water Solutions

Study of reactivity of neptunium ions toward oh radicals in perchloric acid solutions by pulse radiolysis method

1982 ◽  
Vol 31 (4) ◽  
pp. 832-834 ◽  
Author(s):  
V. P. Shilov ◽  
A. M. Fedoseev ◽  
A. K. Pikaev
Keyword(s):  
Perchloric Acid ◽  
Pulse Radiolysis ◽  
Oh Radicals ◽  
Acid Solutions

Reactions of OH Radicals with Acetylacetone in Aqueous Solution. A Pulse Radiolysis and Electron Spin Resonance Study

1982 ◽  
Vol 37 (3) ◽  
pp. 368-375 ◽  
Author(s):  
R. K. Broszkiewicz ◽  
T. Söylemez ◽  
D. Schulte-Frohlinde
Keyword(s):  
Double Bond ◽  
Pulse Radiolysis ◽  
Visible Region ◽  
Alkaline Condition ◽  
Main Reaction ◽  
Electron Spin Resonance Study ◽  
Oh Radicals ◽  
Oh Radical ◽  
Keto Form ◽  
Optical Absorbance

Abstract Pulse radiolysis experiments monitoring optical absorbance as well as conductivity and in-situ ESR radiolysis studies show that the OH radical reacts with the enol (k=8.6 x 109 M-1 s-1) and the enolate (k = 7.4 X 109 M-1 s-1) forms of acetylacetone by addition to the C = C double bond in aqueous N2O saturated solution. The OH reaction with enol leads to equal amounts of two radicals, CH3COCHOHCOHCH3 (2) and CH3COCHC(OH)2CH3 (4), as determined by scavenger reactions. At pH less than 1 the radical CH3COCHCOCH3 (1) is observed by ESR spectroscopy showing that radical 2 and/or 4 eliminate water by proton catalyzed reactions. Under alkaline condition the OH adducts to the enolate eliminate OH -with rate constants larger than 105 s-1 leading to radical 1. G(OH-) is determined to be 5.6 showing that addition is the main reaction of OH with enolate. To a much smaller degree the OH radical is proposed to abstract an H atom from that CH3 group which is attached to the C -C double bond in enol and enolate, producing substituted allyl radicals which absorb in the visible region. The reaction of OH with the keto form has not been observed indicating that the rate constant of this reaction is significantly smaller than those with enol and enolate.

Yield and properties of solvated electrons created by the γ radiolysis of hexamethylphosphorotriamide

1977 ◽  
Vol 55 (11) ◽  
pp. 1832-1835 ◽  
Author(s):  
M. C. Lebas ◽  
J. Sutton ◽  
A. M. Koulkes-Pujo
Keyword(s):  
Pulse Radiolysis ◽  
Total Yield ◽  
Solvated Electron ◽  
Solvated Electrons ◽  
Γ Rays

According to various authors, the value of the yield of the solvated electron in the pulse radiolysis of hexamethylphosphorotriamide (HMPT) varies from 1.2 to 2.4 and increases to 4.2 or 3.1 in the presence of NaBr. We exposed this compound to γ rays after purification and saturation with N2O. N2 was formed with a yield G(N2) = 4.4 ± 0.4. After elimination of a certain number of processes which might also lead to N2 formation, it was concluded that this G(N2) corresponds to the total yield of electrons. This value was confirmed by measuring G(Br−) obtained by radiolysis of HMPT with p-bromophenol as a scavenger. The yield of N2 remains constant whenever solutes generally known as good electron scavengers are added (H+, CH3COCH3, NO3−). An interpretation of the results leads to the suggestion of the formation of a dielectron in this medium.

Experimental Data and Behavior of Starch/Water Solutions with an Ultrafiltration Module

1996 ◽  
Vol 31 (2) ◽  
pp. 173-188 ◽  
Author(s):  
A. Gomez-Gotor ◽  
P. Susial ◽  
A. Guerra ◽  
B. Ibarra
Keyword(s):  
Experimental Data ◽  
Water Solutions ◽  
And Behavior

Pulse Radiolysis of Cycloserine in Aqueous Solutions. One-Electron Oxidation by OH Radicals

1984 ◽  
Vol 57 (12) ◽  
pp. 3403-3407 ◽  
Author(s):  
Masako Tanaka ◽  
Hiroshi Sakuma ◽  
Osamu Kohanawa ◽  
Seijun Fukaya ◽  
Meiseki Katayama
Keyword(s):  
Aqueous Solutions ◽  
Pulse Radiolysis ◽  
Oh Radicals
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