Concentrated solutions, complications irradiation

There are thus two complications in the irradiation of concentrated solutions. First, if a solute is present in high concentration, it can directly absorb a significant portion of the energy deposited and contribute to the radical population. Second, the solute can also affect the primary yield of species by scavenging additional primary species in the spurs and tracks, species that would... 

The ultraviolet irradiation of halogenonitrobenzenes dissolved in ethyl ether or tetrahy-drofuran leads to an increase in the electrical conductivity of the solution relaxation of the conductivity is observed after the irradiation is stopped384. The kinetics appeared to be complicated the structure of the compound, its concentration, the nature of the solvent, the temperature, the time of irradiation as well as the light intensity had an influence on the effects. The photodegradation of three nitrochlorobenzene isomers in pure water and river water under irradiation follows first-order reaction kinetics the rate constants for the three isomers decrease in the order p-> o-> m-nitrochlorobenzene385. 

One of the most important parameters controlling iodine volatility is sump water pH not only will the I2 hydrolysis equilibrium and the iodine partition coefficient be affected by this parameter, but the product yields of radiolytic reactions and the extent of formation of organoiodine compounds as well. Because of the lack of practical experience, the sump water pH to be expected under severe accident conditions has to be calculated on the basis of assumed concentrations of potential sump water ingredients. In Table 7.17. (according to Beahm et al., 1992) an overview of substances to be expected in the sump water, which would effect a shift in solution pH either to lower or to higher values, is given. Besides these chemical substances, radiation may also affect sump water pH irradiation of trisodium phosphate solution (5.3 kGy/h) was reported to decrease the pH from an initial value of 9.0 to about 4.0 after 60 hours of irradiation (Beahm et al., 1992). It is obvious that in such a complicated system definition of the sump water pH to be expected in a real severe reactor accident is a difficult task. Nonetheless, a model for calculation has been developed by Weber et al. (1992). 

Attack of cyanide at polyaminocarboxylatonickel(II) complexes has been much studied kinetically. Now the first report has appeared on the kinetics of cyanide reaction with an analogous iron(III) complex, [Fe(edta)(OH)]. The reaction sequence involves substitution steps giving [Fe(CN)5(OH)] and then [Fe(CN)6] , which finally is reduced by the edta to [Fe(CN)6] ". The initial reaction between [Fe(edta)(OH)] and cyanide has a complicated dependence on cyanide concentration, but the subsequent reaction of [Fe(CN)5(OH)] with cyanide follows simple second-order kinetics. The kinetics of the reverse step, [Fe(CN)5(OH)] with edta, were also examined. Brief irradiation of [Fe(CN)5(OH2)f in aqueous solution in the presence of 1,10-phenanthroline yields [Fe(phen)3] and [Fe(CN)6]. Longer irradiation results in some reduction to iron(II), producing [Fe(phen)3] and [Fe(phen)(CN)4] . ... 

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