Chlorine radioactive, production

Some radioactive bromine (half-life 36 hours), in the form of ammonium bromide, was put into a brine stream as a radioactive tracer. At another plant 30 km away, the brine stream was electrolyzed to produce chlorine. Radioactive bromine entered the chlorine stream and subsequently concentrated in the base of a distillation column, which removed heavy ends. This column was fitted with a radioactive-level controller. The radioactive bromine affected the level controller, which registered a low level and closed the bottom valve on the column. The column became flooded. There was no injury, but production was interrupted. 

If the oxidizing agent, Co(NH3)5Cl2+, is furnished with radioactive chlorine, the product, Cr(H 0)5Cl2+, contains active chlorine. However, if the chlorine in Co(NH3)5Cl2+ is inactive but the reaction is carried out qu ekly in the presence of active Cl in solution, essentially none of the active chlorine is incorporated into the chromium complex. 

In order to explain the behavior of recoil chlorine atoms in liquid hydrocarbon media. Miller and Dodson (56) proposed that every recoil atom forms an excited intermediate complex with the hydrocarbon diluent, and that this complex then decomposes by a number of different paths, leading to the various radioactive products. They also showed that the concept of elastic atom-atom collisions could be entirely relinquished... 

Tetrachlorodibenzo- -dioxm- C, U.L. 2,7-Dichlorodibenzo-p-dioxin- C, U.L. (0.500 gram) was stirred with 10 ml of chloroform containing trace amounts of FeCls and L and heated to reflux temperature while chlorine gas was passed into the mixture for 18 hours. After cooling, the white insoluble product was collected by filtration and triturated with 15 ml of boiling chloroform. The insoluble portion was transferred to a sublimation flask where it was vacuum-sublimed at 140 °C. The sublimate was recrystallized from 2.5 ml of anisole and washed with chloroform. The product weighed 0.229 gram and contained 2.9 /xCi of radioactivity per mg. 

Crystallisation was one of the earliest methods used for separation of radioactive microcomponents from a mass of inert material. Uranium X, a thorium isotope, is readily concentrated in good yield in the mother liquors of crystallisation of uranyl nitrate (11), (33), (108). A similar method has been used to separate sulphur-35 [produced by the (n, p) reaction on chlorine-35] from pile irradiated sodium ot potassium chloride (54), (133). Advantage is taken of the low solubility of the target materials in concentrated ice-cold hydrochloric acid, when the sulphur-35 as sulphate remains in the mother-liquors. Subsequent purification of the sulphur-35 from small amounts of phosphorus-32 produced by the (n, a) reaction on the chlorine is, of course, required. Other examples are the precipitation of barium chloride containing barium-1 from concentrated hydrochloric acid solution, leaving the daughter product, carrier-free caesium-131, in solution (21) and a similar separation of calcium-45 from added barium carrier has been used (60). 

Historically, chlorine was the first target used to trap neutrinos. Chlorine-37 is mainly sensitive to high-energy neutrinos emanating from marginal fusion reactions (2 out of 10000) which lead to production of boron-8. On rather rare occasions, under the impact of neutrinos, chlorine-37 is transformed into radioactive argon-37 which is easy to detect by its radiation. However, the myriads of low-energy neutrinos completely escape its notice. 

Recent work (Brown and Pearsall, 15) has indicated that while hydrogen aluminum tetrachloride is nonexistent, interaction of aluminum chloride and hydrogen chloride does occur in the presence of substances (such as benzene and presumably, olefins) to which basic properties may be ascribed. It may be concluded that while hydrogen aluminum tetrachloride is an unstable acid, its esters are fairly stable. Further evidence in support of the hypothesis that metal halides cause the ionization of alkyl halides (the products of the addition of the hydrogen halide promoters to the olefins) is found in the fact that exchange of radioactive chlorine atoms for ordinary chlorine atoms occurs when ferf-butyl chloride is treated with aluminum chloride containing radioactive chlorine atoms the hydrogen chloride which is evolved is radioactive (Fair-brother, 16). 

After a new (and unusual) mechanism, such as the benzyne mechanism for nucleophilic aromatic substitution, is proposed, experiments are usually designed to test that mechanism. A classic experiment supporting the benzyne mechanism used a radioactive carbon label. Examination of the mechanism shown in Figure 17.6 shows that the carbon bonded to the leaving chlorine and the carbon ortho to it become equivalent in the benzyne intermediate. Consider what would happen if the carbon bonded to the chlorine were a radioactive isotope of carbon (l4C) rather than the normal isotope of carbon (I2C). If we follow the position of the radioactive carbon label through the mechanism of Figure 17.6, we find that the label should be equally distributed between the carbon attached to the amino group in the product and the carbon ortho to it. 

Once the radioactive fission products are isolated by one of the separation processes, the major problem in the nuclear chemical industry must be faced since radioactivity cannot be immediately destroyed (see Fig. 10-7c for curie level of fission-product isotopes versus elapsed time after removal from the neutron source). This source of radiation energy can be employed in the food-processing industries for sterilization and in the chemical industries for such processes as hydrogenation, chlorination, isomerization, and polymerization. Design of radiation facilities to economically employ spent reactor fuel elements, composite or individually isolated fission products such as cesium 137, is one of the problems facing the design engineer in the nuclear field. 

Chlorine has two stable nuclides, C1 and Cl. In contrast, Cl is a radioactive nuclide that decays by beta emission, (a) What is the product of decay of Cl (b) Based on the empirical rules about nuclear stability, explain why the nucleus of Cl is less stable than either Cl or Cl. 

Chlorine-36 is a cosmogenic radioactive (i.e., unstable) nuclide that is produced by a nuclear spallation reaction in grains of metallic iron in stony meteorites. After a meteorite specimen has landed on the surface of the Earth, the production of all cosmogenic radionuclides stops and Cl decays at a rate depending on its halflife. The terrestrial age of a meteorite is calculated from the remaining concentration of Cl by an application of the law of radioactivity (Faure and Mensing 2005). 

There is subterranean production of chlorine-36 and the world average chlorine contents of granite and basalt have been given as around 50 and 200 ppm, respectively. Sedimentary rocks have variable contents ranging from 10 ppm in sandstones to 20,000 ppm in deep-sea limestones. Rock outcrops are exposed to the cosmic neutron flux so that some chlorine-36 results from neutron capture by chlorine-35, but, below a few meters, it is ineffectual. Nonetheless, some chlorine-36 results from an in situ neutron flux in rock matrices caused by (a,n) reactions triggered by alpha particles from uranium and thorium radioactive decay systems. This flux may be of the order of 10 cm s (Kuhn et al. 1984). 

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