The pulse radiolysis of aqueous solutions of some inorganic compounds

1965 ◽  
Vol 286 (1406) ◽  
pp. 320-336 ◽  
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Absorption Spectra ◽  
Rate Constants ◽  
Pulse Radiolysis ◽  
Inorganic Compounds ◽  
Absolute Rate ◽  
Transient Species ◽  
Temperature Coefficients ◽  
Complex Metal

The reactions of the hydrated electron, e — aq. with a variety of inorganic metal ions, complex metal ions and anions have been investigated with pulses of 4 MeV electrons. Absolute rate constants have been measured in each case and some temperature coefficients have also been determined. Absorption spectra of transient species produced by the pulse have been obtained. Some of these species are unstable valency states produced by reduction withe — aq. , e.g. Ni + , Cr v ; others are the result of oxidation by OH, e.g. Cu 3+ . We have obtained rate constants for the reactions OH+Cu 2+ and H+MnO - 4 . The significance of the rate constants and spectra is discussed.

Pulse radiolysis of aqueous solutions of N-Vinylpyrrolidin-2-one and Poly(N-vinylpyrrolidin-2-one)

1981 ◽  
Vol 34 (7) ◽  
pp. 1423 ◽  
Author(s):  
JE Davis ◽  
DF Sangster ◽  
E Senogles
Keyword(s):  
Aqueous Solutions ◽  
Hydroxyl Radical ◽  
Absorption Spectra ◽  
Rate Constant ◽  
Rate Constants ◽  
Pulse Radiolysis ◽  
Kinetic Method ◽  
Transient Species ◽  
Radical Scavengers ◽  
Dilute Aqueous Solutions

The absorption spectra of transient species produced when dilute aqueous solutions of N-vinylpyrrolidin-2-one (vp) and poly(N- vinylpyrrolidin-2-one) (pvp) are subjected to pulse radiolysis in the presence and absence of radical scavengers have been obtained and compared with those obtained from analogous compounds. The precise structure of the transients has not been established. Rate constants for the reaction of the hydroxyl radical with vp and pvp have been evaluated both by a competition kinetic method and by direct observation of the build-up of transient species: k(vp+·OH) = (6.4-8.1) × 109 dm3 mol-1 s-1 and k(pvp+·OH) = (1.5-2.3) × 108 dm3 mol-1 s-1 at 25°C. The rate constant for the reaction of the hydrated electron with vp has been determined as(1.6�0.3) × 109 dm3 mol-1 s-1 at 25°C. Rate constants for decay of the transient species have also been evaluated at 25°C: 2k(vp- OH·) = (8.1�1.0)× 108 dm3 mol-1 s-1; 2k(vp-e-) = (1.7�0.2) × 109 dm3 mol-1 s-1 and 2k(pvp-OH·) = (1.5�0.2) × 108 dm3 mol-1 s-1.

Notizen: Pulse Radiolysis of Selenium Containing Compounds: Selenomethionine

1974 ◽  
Vol 29 (7-8) ◽  
pp. 571-572 ◽  
Author(s):  
Maurizio Tamba ◽  
Sergio Bonora ◽  
Roberto Badiello
Keyword(s):  
Optical Absorption ◽  
Aqueous Solutions ◽  
Absorption Spectra ◽  
Pulse Radiolysis ◽  
Oh Radicals ◽  
Optical Absorption Spectra ◽  
Transient Species ◽  
Decay Kinetics ◽  
Kinetics Of

The pulse radiolysis of aqueous solutions of selenomethionine has been studied under both neutral and acid conditions and the transient optical absorption spectra have been observed. The reactivities of both eāq and OH radicals have been measured as well as the formation and the decay kinetics of the transient species.

A Pulse Radiolysis Study of the Reaction of the Sulfate Radical Ion in Aqueous Solutions of Styrene

1979 ◽  
Vol 32 (12) ◽  
pp. 2611 ◽  
Author(s):  
NA McAskill ◽  
DF Sangster
Keyword(s):  
Aqueous Solutions ◽  
Absorption Spectra ◽  
Pulse Radiolysis ◽  
Cation Radical ◽  
Ultraviolet Absorption ◽  
Sulfate Radical ◽  
Transient Species ◽  
Acetonitrile Solutions ◽  
Type Radical

The ultraviolet absorption spectra of the transient species formed during the pulse radiolysis of styrene and peroxydisulfate (S2O82)solutions showed that a benzyl-type radical was formed from styrene and the SO4- radical. The effect of adding Cl- was also studied. These results are in conflict with the claim1 that a phenylethyl radical was formed from SO4-' via the styrene cation radical. That study was made on acetonitrile solutions of styrene, S2O82-, CuCl2 and LiCl and the present results suggest that up to 70% of the SO4-' radicals may have been converted into Cl2-1 radical which then reacted with styrene.

Transient species produced in irradiated water and aqueous solutions containing oxygen

1966 ◽  
Vol 289 (1418) ◽  
pp. 321-341 ◽  
Keyword(s):  
Aqueous Solution ◽  
Absorption Band ◽  
Aqueous Solutions ◽  
Rate Constants ◽  
Alkaline Solutions ◽  
Absolute Rate ◽  
Radical Ions ◽  
Transient Species ◽  
Fast Electrons ◽  
Transient Spectra

Transient spectra of a number of radicals and radical ions have been observed in aqueous solution saturated with oxygen and irradiated by a short intense pulse of fast electrons. Depending upon the conditions of pH and upon solute concentrations, absorption maxima are produced in both the visible and ultraviolet regions of the spectrum. In oxygenated alkaline solutions the u.v. absorption contains four components which decay at different rates. One of these is the second absorption band of 0 - 3 and it is concluded that the others are due to the species O - 2 , HO - 3 and HO - 2 . It is suggested that the short lived u.v. absorption observed in alkaline N20 saturated solution is due to the species O - . Absolute rate constants have been obtained for several of the reactions involved and a comprehensive mechanism for the radiolysis is proposed.

The radiolysis of aqueous solutions of oxybromine compounds; the spectra and reactions of BrO and BrO 2

1968 ◽  
Vol 304 (1479) ◽  
pp. 427-439 ◽  
Keyword(s):  
Aqueous Solution ◽  
Steady State ◽  
Aqueous Solutions ◽  
Absorption Spectra ◽  
Rate Constants ◽  
Pulse Radiolysis ◽  
Kinetic Spectroscopy

Pulse radiolysis supplemented by steady state radiolysis of aqueous solutions containing some of the following solutes: N 2 O, Br - , BrO - , BrO - 2 , BrO - 3 , CO 2- 3 , and OH - has been used to identify the absorption spectra of BrO ( λ max = 350 nm) and BrO 2 ( λ max = 475 nm) and to evaluate the following rate constants (units, M -1 s -1 ): e - aq. + BrO - → Br - + O - (2.3 ± 0.5 x 10 10 ); e - aq. + BrO - 2 → BrO + O 2- (1.8 ± 0.2 x 10 10 ); e - aq. + BrO - 3 → BrO 2 + O 2- (4.1 ± 0.2 x 10 9 ); OH + BrO - → OH - + BrO (4.5 x 10 9 ); O - + BrO - → BrO + O 2- (4.6 x 10 9 ); OH + BrO - 2 → OH - + BrO 2 (1.9 x 10 9 ); Br - 2 + BrO - → BrO + 2Br - (8.0 ± 0.7 x 10 7 ); Br - 2 + BrO - 2 → BrO + Br - + BrO - (8.0 ± 0.8 x 10 7 ); BrO + BrO - 2 → BrO - + BrO 2 (3.4 ± 0.7 x 10 8 ); 2BrO 2 ⇌ Br 2 O 4 ( k = 1.4 x 10 9 and K = 19 M -1 ); Br 2 O 4 + OH - → H + + BrO - 2 + BrO - 3 (7 x 10 8 ); 2BrO + H 2 O → BrO - + BrO - 2 + 2H + (4.9 ± 1.0 x10 9 ); CO - 3 + BrO - → CO 2- 3 + BrO (4.3 ± 0.4 x 10 7 ); CO - 3 + BrO - 2 → CO 2- 3 + BrO 2 (1.1 ± 0.1 x 10 8 ). In contrast to their chlorine analogues, little is known of the chemistry of the bromine oxides in aqueous solution. In this paper we describe the methods of formation and identification of the radicals BrO and BrO 2 , and their reactions with various oxybromine species, as elucidated by the techniques of pulse radiolysis and kinetic spectroscopy applied to aqueous solutions containing oxybromine anions.

The Mechanism of Decay of the Radical HO—CH—CH2—OCOCH3 in Aqueous Solutions. A Conductometric Pulse Radiolysis Study

1976 ◽  
Vol 31 (7) ◽  
pp. 960-964 ◽  
Author(s):  
G. Koltzenburg ◽  
T. Matsushige ◽  
D. Schulte-Frohlinde
Keyword(s):  
Acetic Acid ◽  
Aqueous Solutions ◽  
Rate Constants ◽  
Pulse Radiolysis ◽  
Electron Pulse ◽  
Rate Determining Step ◽  
A Value

From conductivity changes following a 1 µs electron pulse applied to Ν2Ο saturated H2O or D2Ο solutions of acetic acid 2-hydroxyethyl esterthe rate constants of the monomolecular decay of the radical HO-ĊH-CH2-OCOCH3 (1) in H2O and of DO-ĊH-CH2-OCOCH3 in D2O were derived, reaction (1).A value of k1 of 5.5 · 105 s-1 ± 25%, at 22 to 24°C, independent of the above solvents and of pH (or pD) was obtained. It is concluded that the rate determining step of reaction (1) is the heterolytic fragmentation of the carbon acetate bond in 1 followed by formation of H+.

KINETICS OF THE OXIDATION OF URANIUM (IV) BY IRON (III) IN AQUEOUS SOLUTIONS OF PERCHLORIC ACID

1955 ◽  
Vol 33 (12) ◽  
pp. 1780-1791 ◽  
Author(s):  
R. H. Betts
Keyword(s):  
Electron Transfer ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Perchloric Acid ◽  
Rate Constants ◽  
Kcal Mole ◽  
Kinetics Of Oxidation ◽  
Temperature Coefficients ◽  
Kinetics Of ◽  
Rate Controlling Step

The kinetics of oxidation of uranium (IV) by iron (III) in aqueous solutions of perchloric acid have been investigated at four temperatures between 3.1 °C. and 24.8 °C. The reaction was followed by measurement of the amount of ferrous ion formed. For the conditions (H+) = 0.1–1.0 M, ionic strength = 1.02, (FeIII) = 10−4–10−5 M, and (UIV) = 10−4–10−5 M, the observed rate law is d(Fe2+)/dt = −2d(UIV)/dt[Formula: see text]K1 and K2 are the first hydrolysis constants for Fe3+ and U4+, respectively, and K′ and K″ are pseudo rate constants. At 24.8 °C., K′ = 2.98 sec.−1, and K″ = 10.6 mole liter−1 sec−1. The corresponding temperature coefficients are ΔH′ = 22.5 kcal./mole and ΔH″ = 24.2 kcal./mole. The kinetics of the process are consistent with a mechanism which involves, as a rate-controlling step, electron transfer between hydrolyzed ions.

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