P. Ya. Glazunov

Mechanism of the radiolytic reduction of quadrivalent cerium in aqueous hydrochloric acid solutions at high-absorbed dose rates

1. The yields of Ce3+ and the sum of peracids H2S2O8 + H2SO5 were determined in the radiolysis of sulfuric acid solutions of ceric sulfate at dose rates of up to 1023 eV/ml · sec. 2. The dependence of G(Ce3+) and G(H2S2O8 + H2SO5) on the H2SO4 and Ce3+ concentrations was investigated at a dose rate of 1023 eV/ml · sec. The yields decrease with increasing Ce3+ concentration. When the H2SO4 concentration is increased, the yield of peracids increases, while the yield of Ce3+ decreases. 3. At a low dose rate, peracids are formed as a result of the direct action of radiation on sulfuric acid. 4. The possible mechanism of the radiolytic transformations of the Ce4+ and Ce3+ ions and the formation of peracids at high absorbed dose rates was considered. 5. The values of the relative rate constants of a number of radiochemical reactions proceeding in aqueous sulfuric acid solutions of Ce4+ and Ce3+ were calculated.

Isomerization of polycrystalline cis-diiododiammineplatinum(II) under the action of ionizing radiation

1. cis-Diammine complexes of platinum(II) are isomerized under the influence of γ irradiation. 2. The isomerization of the cis-diiodo complexes of platinum(II) proceeds more readily and at lower values of the absorbed doses than decomposition with liberation of the metal. 3. The isomerization of cis-diiododiammineplatinum(II) under the action ofγ radiation proceeds more readily than the analogous process in cis-dichlorodiammineplatinum(II). This may be due to the higher trans influence of the iodo group in comparison with the trans influence of chlorine.

High radiation stability of certain acidohydroxo complexes of platinum (IV)

1. A study of the radiation chemical properties of acidohydroxo complexes of Pt(IV) showed that the compounds K2PtCl4 (OH)2, (NH4)2PtCl4(OH)2, (NH4)2PtBr4(OH)2, (NH4)2PtI4(OH)2, K2Pt(OH)6, H2Pt(OH)6 possess high radiation chemical stability. 2. The thermal stability of the complexes drops with increasing reducing properties of the acidoligand; moreover, potassium salts are characterized by a lower temperature of the beginning of decomposition than ammonium salts.

Approximate values of the rate constants of radiation reaction of hydrogen atoms and hydroxyl radicals in aqueous solutions

1. The radiolysis of aqueous sulfuric acid solutions of ferrosulfate, containing oxygen, was investigated under the action of pulsed electronic radiation. The influence of the addition of NaCl on the value of G(Fe+3) was detected. 2. The mechanism of the radiolytic oxidation of Fe+2 ions at high absorbed dose rates was considered. The decrease in the yield of Fe+3 is due to competition of the reactions of H + OH, Fe2+ + OH and H + O2. 3. Two independent methods of kinetic treatment of the experimental data were used, one of which makes it possible to find the ratio of three reaction rate constants, while the other permits the finding of the ratio of two constants. The absolute values of the reaction rate constants were estimated:\(k_{Fe^{2 + } + OH} = 2.7\cdot10^8 ;k_{H + O_2 } = 5.3\cdot10^9 \) and kH + OH=4.5·1010 liters/mole·sec. 4. The rate constants of a number of radiation reactions of H and OH radicals were estimated on the basis of the values of the relative constants available in the literature and the absolute values obtained.

Electron paramagnetic resonance spectra of irradiated frozen aqueous solutions Communication 2. Aqueous solutions of sodium nitrite

1. The EPR spectra of irradiated frozen aqueous solutions of sodium nitrite were investigated in acid, neutral, and alkaline media. 2. The EPR spectra of acid and neutral solutions are identical and are due to the NO2 radicals, while in alkaline medium two more radicals are formed: NO2−2 and O−. 3. The radical yields were measured at temperatures of −196 and −150‡ as a function of the concentration of NaNO2 and alkali. With increasing concentration of these substances, the radical yields increase. The possible causes of this phenomenon were discussed. 4. Thermal stability of the radical products formed during irradiation was studied, and it was found that under definite conditions the OH and O− radicals interact with the NO2− ions during unfreezing.

Electron paramagnetic resonance spectra of irradiated frozen aqueous solutions Communication 1. Solutions of alkalis

1. The radical products in irradiated frozen solutions of KOH in H2O and D2O were investigated by the electron paramagnetic resonance method at various concentrations and in the temperature range from −196 to −100°. 2. Stabilization of the hydrated electron and conversion of the OH radical to the ion radical O− · nH2O occur in alkaline medium. 3. H and D atoms were detected in irradiated concentrated frozen solutions of KOH in H2O and D2O at −196° 4. The thermal stability of the radical products in neutral water and in solutions of alkali of various concentrations was investigated. 5. The yields of radical products in alkaline medium were determined at temperatures of −196 and −150° as a function of the KOH concentration, and they were found to be increased in comparison with neutral frozen water.

Radiation method of preparing highly dispersed metals and oxides

1. During topochemical decomposition processes of various solid compounds, hydroxides, oxalates and carbonates under the effect of radiation of low temperatures, highly dispersed oxides and metals are formed. 2. Metals and oxides prepared by the radiation method have considerably greater specific surfaces than those of the same substances obtained by thermal decomposition.

On the influence of the radioactive radiation of a solid body on its catalytic properties

1. The action of radioactive catalysts on the dehydration of cyclohexanol was investigated; the catalysts used were MgSO4 with Na2SO4 containing S35 and MgSO4 with CaCl2 containing Ca45. 2. The increase of catalytic activity of the radioactive catalysts in comparison with the non-radioactive, which was discovered earlier by the same authors, was confirmed by a large number of facts. 3. The catalytic activity decreased in proportion to the loss of radioactivity of the catalyst as a consequence of the disintegration of the radioactive S35 and Ca45. 4. The bombardment of the surface of the non-radioactive catalyst with fast electrons (800 kev) did not give a noticeable effect, in contrast to the action of beta particles from S35 or Ca45 which were introduced into the composition of the catalyst.

Effect of solution concentration on the radiation yield of ferrous iron oxidation at high radiation dose strengths

The radiation yield of the oxidation of ferrous iron depends considerably on the original solution concentration at high radiation dose strengths.

Radiolytic reduction of tetravalent cerium at dose strengths up to 1023 ev/ml · sec

1. The radiolytic reduction yield of Ce4+ in aqueous sulfuric acid solutions increases appreciably, beginning with a dose strength of ∼ 1021 ev/ml · sec. 2. The increase in the radiation yield of Ce3+ is explained by overlapping of the tracks of ionizing particles at high dose strengths.