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Exposure of a range of organic bromides to 6oCo prays at 77 K, either pure or in p2rdeuteromethanol gave, amongst others, radicals having e.s.r. features thought to be characteristic of a-bromo radicals, R2cBr. Analyses of such spectra are given, including the use of selected single crystal spectra and measurements at different microwave frequencies. The effect of the large bromine quadrupole interaction is indicated. It is concluded that the unpaired electron is delocalised onto bromine to the extent of ca. 19 %, this bsing relatively insensitive to the nature of the other substituents. Exposure of bromomaleic acid to hydrogen atoms gave an a-bromo radical exhibiting a large hyperfine coupling (38 G) to a single hydrogen, which was shown to be the added atom by us? of deuterium in place of hydrogen. For the radical H2C=CHcHBr structure H&-CH=CHBr makes only a minor contribution. Possible radiation mechanisms are discussed.

Hydrous manganese oxide (HMO) is exploited as adsorbent for the decontamination study of strontium ions from aqueous radioactive waste solutions under simulated conditions using batch technique. The dependences of removal on various physicochemical conditions, such as contact time, concentration, temperature and pH of the adsorptive solution, were established using radiotracer technique. The results show that adsorption essentially reaches a plateau value in ca. 90 min, and the data thus obtained fit well into the classical Freundlich adsorption isotherm over a wide range of concentrations (IO -2 -IO -7 M). Lower desorption values, little affected by increase in temperature, show the process to be irreversible. The exposure of HMO to neutrons and "/-radiations from a 11.1 GBq neutron source up to certain periods results in a nominal change in sorption characteristics, indicating it be radiation-stable.

Apolar aprotic solvents are particularly advantageous for investigating the intrinsic ortho effect free from complications of specific solvent effects. A kinetic study for toluene-phase proton transfers between ortho F, Cl, Br, I, OMe, OEt, OPh, OAc, Me, NO(2), COMe, COPh, OH, NH(2), and H benzoic acids and crystal violet carbinol base has shown the forward rate constant (log k(+1)) is the most appropriate reactivity parameter in toluene. log k(+1) (toluene) as compared to other reported reactivity parameters in benzene, toluene, or chlorobenzene has been found more sensitive to the ortho substituent effect. The regression results of the correlation of log k(+1) (toluene) of the acids (except OH and NH(2) substituted ones) according to seven ortho effect models are all very significant, and the best result is given by Fujita-Nishioka's model. The overall analysis reveals that a substituent's ortho effect pattern is a 58:24:18 ratio of its ordinary electrical, proximity electrical, and steric effects and that the proximity electrical effect is the major component to account for the peculiarity of the substituent's ortho effect. The results further favor the transmission of this effect mainly through the molecular cavity. The effect may, however, be outweighed by the steric component for bulky enough substituents, e.g., Me. The enhanced strength exhibited by salicylic acid in toluene has been quantitatively described using Pytela-Liška's σ(HB)(i) parameter. The abnormally high log k(+1) observed for anthranilic acid in toluene has been ascribed to a very extensive homoconjugation in its acid-acid anion complex induced by the acid's three hydrogen bond donors.