The catalytic wet air oxidation of aqueous solution containing 1000 ppm aniline was conducted in a trickle-bed reactor packed with a novel nanocasted Mn-Ce-oxide catalyst (surface area of 300 m2/g) prepared using SBA-15 silica as a hard template. A range of liquid hourly space velocities (5-20 h(-1)) and temperatures (110-140 degrees C) at 10 bar of oxygen were tested. The experiments were conducted to provide the intrinsic performance of the catalysts. Complete aniline conversion, 90% TOC conversion, and 80% nitrogen mineralization were achieved at 140 degrees C and 5 h(-1). Blank experiments yielded relatively low homogeneous aniline (<35%) and negligible TOC conversions. Fast deactivation of the catalysts was experienced due to leaching caused by complexation with aniline. Acidification of the solution with HCI (molar HCI to aniline ratio of 1.2) was necessary to avoid colloidization and leaching of the nanoparticulate catalyst components. The catalyst displayed stable performance for over 200 h on stream.

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The nature of the reactions following neutron capture by the bromine atom in ethyl bromide has been investigated by analysing the products at different free bromine concentrations. The products from the processes associated with the slowing down of the energetic atoms consist largely of compounds which could only be produced from highly fragmented ethyl bromide molecules. By contrast, the product from the ensuing diffusion-dependent reactions consists only of ethyl bromide.

Band 1, Heft 1 1962 MIRIAM MILMAN, Mechanisms for the Reactions Following Radiative Neutron Capture etc.15 results obtained, which are similar to that of Fig. 3 showing that the graded TBP concentration was not very effective. In order to simplify the operation, conditions applied to Experiment No. 2 are preferable to those of Experiment No. 5. ConclusionLooking over the results obtained from these experiments stated above, it is clear that uranium, plutonium and fission products can be succesfully separated with the present method. A merit of the present method is that uranium, plutonium and fission products are all obtained in aqueous solution, thus eliminating the need of backextraction, and simplifying subsequent processing of the obtained solution. An additional advantage is that the organic solution in the extraction cells can be used over and over again. This method may be applied to large scale separation by the use of other types of apparatus like a train of mixer-settlers. SummaryThe available data together with some recent work done by the author, have been reconsidered with regard to establishing a unified approach to the chemistry of hot atoms. It was found that the "Impact Model", originally proposed for the hot reactions of tritium atoms in gases, can also give an adequate picture for the reactions of activated halogen atoms in liquid organic halides.Zusammenfassung Eine allgemeingültige Beschreibung des chemischen Verhaltens energiereicher Atome wird an Hand der bekannten Tatsachen sowie neuer Arbeiten der Verfasserin versucht. Es stellt sich heraus, daß das "Zusammenstoßmodell", das ursprünglich für die Reaktion heißer Tritiumatome in Gasen vorgeschlagen wurde, auch die Reaktionen aktivierter Halogenatome in flüssigen organischen jHalogenverbindungen auf eine befriedigende Art erklären kann. R£sum6Les connaissances actuelles combinfes avec des resultats nouveaux de l'auteur ont ete reconsiderees afin de trouver une description unifide du comportement chimique des atomes chauds. On trouve que le «modele de collision», qui a ktk introduit d'abord pour expliquerles reactions chaudes des atomes de tritium dans les gaz, se prete aussi au traitement des r6actions des atomes d'halogene activ£s dans les halog6nures organiques liquides. IntroductionThe irradiation of matter with particles or photons produces hot atoms. The chemical reactions of these activated species are often unique, in the sense that they are· forbidden to the same atoms at thermal energies. It is characteristic of hot reactions that their yield is not dependent on temperature or on low concentrations of radical scavengers, but is diminished by the presence of "moderators" that remove the kinetic or electronic energy of the activated atom. A hot atom born with kinetic energy (due to the recoil of the tagged atom after particle or photon emission) and/or positive charge (as a result of internal conversion or Auger electron emission) can enter stable combination after loosing most of its excess energy by successive collisions with the su...

Factors affecting the distribution of the isotopes SOBr, 80Br*, and *2Br among the compounds produced in neutron-irradiated bromobenzene have been investigated. A radiation-induced exchange between bromobenzene and bromine atoms produced by radiolysis is largely responsible for the greater retention of the longer-lived isotopes, the exchanged atoms occupying the same positions in the benzene ring as the original atoms. The chief cause of the variable results obtained previously is probably the presence of water in the bromobenzene, which under the influence of radiation reacts to give phenolic products which with elementary radio-bromine then give other organic compounds.WHEN organic bromides are bombarded with slow neutrons, a proportion of the radiobromine produced can be extracted with an aqueous reagent, e.g., sulphite or bromide solutions. This is because the recoil energies of the bromine atoms from the y-rays emitted on neutron capture are greater than the chemical binding energies of C-Br bonds, so that dissociation occurs, leaving some radioactive bromine combined in new chemical species (cf. Szilard and Chalmers 1).(half-life 18 min.), its isomer 80Br* (4.5 hr.) which decays into by emission of weak y-rays and internal conversion electrons, and 82Br (35 hr.). Libby and his c o -a u t h o r ~, ~, ~ working with isoand ut-propyl bromide, have reported that the retentions (fraction of radio-bromine left in organic combination) of these isotopes are the same; we have confirmed this for ethyl bromide and ethylene dibromide containing small quantities of elementary bromine (unpublished work). Capron and Cr&vecoeur,* using bromobenzene, found a difference in the retentions of and 80Br*, that of the longer-lived isotope being the greater: they also found that the ratio of the isotopic retentions depended on the energy distribution of the bombarding neutrons, and concluded that the 80Br and atoms produced had different recoil energies which arose from variations in the y-ray cascades following neutron capture. find similar effects in bromoform, and in isoand ut-propyl bromide; however, they admitted that the purity of the last two compounds was poor, and, as Libby and his coworkers 293 have pointed out, the presence of impurities which could react with inorganic bromine to return it to organic combination would favour greater retentions for the longerlived isotopes.in the propyl bromides, bromoform, and bromobenzene, and found that the isotopic retentions were the same in the aliphatic bromides, but were unable to confirm this for bromobenzene owing to poor reproducibility of results, and they concluded that the retention differences Three possible radioactive isotopes of bromine may be produced by this means :