Moderator effects on recoil tritium reactions with lithium beta-phenylpropionate

The recoil tritium reactions were studied with lithium beta-phenylpropionate having both the aromatic and aliphatic C-H bonds in the molecule, mainly in terms of the moderator effect on the intramolecular tritium distribution. Recoil tritium atoms were produced by the 6Li(n,alpha)3H reaction. Water molecules were used as the moderator. The tritium activity of the ethylene group represented relative to that of the corresponding ring assumed as a standard (= 100) is 30 in the moderator-free system and is reduced to 13 in the moderated system in which the H2O/beta-PhC2H4CO2Li mole ratio is 328. In the ring, the tritium distribution shows a slight ortho- and para-orientation in the moderator-free system and the selectivity is pronounced when the H2O/beta-PhC2H4CO2Li mole ratio is large. The data show that the aromatic ring tritiation in the moderated system is given by increasing contribution of the reactions of tritium atoms having lower energy than the threshold energy of the ethylene group tritiation.     

Solid state reactivity of organic compounds with inorganic compounds II.

Cobalt acetate reacts with aniline, 2-, 3- and 4-chloroanilinehydrobromides in the solid state to give the products CoBr₂. 2 amine in which the acetate is replaced by bromide and the amine gets attached to the metal in a concerted step. The products have been identified by elemental, spectral and thermoanalytical methods. The kinetics of these reactions have been studied by the mass loss method. The values of energy of activation are 142.0, 41.0, 77.0 and 71.4 kJ mol^?1. The greater reactivity of 2-chloro is due to ortho effect. An intermediate adduct (RNH₃)₂(Co(CH₃COO)₂Br₂) has also been characterized.     

Reaction of recoil tritium atoms with ethyl alcohol in the gas phase

Reaction of recoil tritium atoms with ethyl alcohol in the gas phase has been studied in the presence of moderator and scavenger. The total amount of tritium produced from³He (n, p) T reaction under given irradiation conditions is determined by adding methane as a monitor for each set of sample. The HT, CH₃T, C₂H₅T and C₂H₄TOH yields were due to the decrease of hot reaction with increasing moderator pressure. On the other hand, the C₂H₃T yield, due to the unimolecular reaction of excited CH₄TOH^* or C₂H₅T^* moleculas, decreased with increasing pressure. All tritiated compounds were analyzed by radio gas chromatography.     

The reactions of recoil tritium atoms with toluene in the C6F6-moderated systems

The T-for-H substitution reaction was studied in the recoil tritium reactions with toluene in C6F6-moderated systems. The moderator-free control experiment showed an approximately uniform labeling in the aromatic ring, with a slightly enhanced reactivity in the ortho- and para-positions (o: 41%, m: 38%, p: 21%) and showed a preference for ring tritiation over methyl group tritiation (23 relative to the corresponding ring assumed as a standard (= 100)). The addition of hexafluorobenzene progressively changed the uniform distribution to a marked ortho- and para-orientation and decreased the relative tritium activity of the methyl group. If the C6F6/PhCH3 mole ratio is 204, the tritium distribution in the ring is o: 53%, m: 22%, p: 25% and the methyl group activity is reduced to 2. The data show the existence of the threshold energy of side chain tritiation and that the selective aromatic ring tritiation is given by increasing contribution of the reactions of tritium atoms having lower energy than the threshold energy.     

Reactions of recoil tritium generated by the3He/n,p/3H reaction with aromatic compounds-intramolecular tritium distribution and radiochemical yield

Reactions of recoil tritium with benzoic acid, acetanilide and -phenethyl alcohol were studied using the³He/n,p/³H reaction. The tritium distribution in the aromatic ring is approximately uniform in all the irradiated compounds and the tritium activity per C–H bond in the methyl and ethylene groups is 7 to 8 relative to that of the corresponding ring as standard /=100/. These findings are substantially the same as those obtained previously by the⁶Li/n,/³H reactions, suggesting the same mechanism of tritiation for both recoil reactions. The tritiated parent compounds were obtained in high radiochemical yields; 45% for benzoic acid, 30% for acetanilide, 12% for -phenethyl alcohol.     

Radio-liquid chromatogrphy for tritium labelled organic compounds using CaF2/Eu/ scintillator

The radio-liquid chromatography for the tritium labelled compoounds was constructed with a CaF₂/Eu/ scintillator and applied successfully to analyze the products of recoil tritium reactions with trans-stilbene. The detection efficiency of tritium of 0.8% and the lowest detectable activity of 60 nCi were obtained for a 100–150 mesh CaF₂/Eu/ scintillator.     

Non-destructive positional analysis of tritium tracer in organic compounds by an adaptation of triton-NMR spectroscopy

For the positional isotopic analysis of tritium-labelled organic compounds which are isolated at the end of a tracer experiment, it is proposed to render high-resolution triton-NMR spectroscopy sufficiently sensitive as follows. Andrew's rotating magnetic field is used to narrow the NMR lines that are detected by observing the anisotropy of the β-radiation of the sample which is kept at 0.01 °K by a helium-dilution refrigerator. In this context, the usefulness of the rotating magnetic field for cryogenic proton-NMR spectroscopy is pointed out.     

Solid state reactivity of organic compounds with inorganic compounds. IV synthesis and thermal decomposition of uranium oxinate in the solid state

8-hydroxyquinoline (oxine) and uranyl acetate react in the solid state in 13 stoichiometry to give UO₂(C₉H₆NO)₂·C₉H₆NOH. This reaction is diffusion controlled with an activation energy of 44.4 kJ mol^–1. The reaction occurs by the surface migration of 8-hydroxyquinoline, which penetrates the product lattice to react with uranyl acetate. The isothermal decomposition of the solution phase product UO₂Q₂·HQ (Q=C₉H₆NO) obeys the Prout-Tompkins equation with an energy of activation of 53.3 kJ mol^–1.

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Zusammenfassung Die Festkörperreaktion von 8-Hydroxychinolin und Uranylazetat im Verhältnis 13 liefert UO₂(G₉H₆NO)₂·C₉H₆NOH. Die Reaktion ist diffusionsbestimmt und besitzt eine Aktivierungsenergie von 44.4 kJmol^–1. Die Reaktion verläuft durch die Oberflächenmigration von 8-Hydroxychinolin, welches zur Reaktion mit Uranylazetat in das Gitter des Produktes eindringt. Die thermische Zersetzung der Mischphase UO₂Q₂·HQ mitQ=C₉H₆NO unterliegt der Prout-Tompkins-Gleichung mit einer Aktivierungsenergie von 53,3 kJ·mol^–1.

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8- 13, UO₂(C₉H₆NO)₂·C₉H₆NOH. 44,4 ·^–1. 8-, . UO₂ Q ₂ · HQ (Q=C₉H₆NO) - 53,3 ·^–1.

     

Chemical states of tritium in solid lithium compounds irradiated with neutrons

Chemical states of tritium existing in neutron-irradiated solid lithium compounds were analyzed using a radiometric method. Nearly 100% of tritium was found in the T⁺ state in LiOH, Li₂O₂ and Li₃N, while the T^– state predominated in LiH, Li₇Pb₂ and Li₂C₂. Tritium incorporated in Li₂O, Li₂S, LiF, LiCl, LiBr and LiI was distributed over the T⁺, T^– and T⁰ states. In Li₂O crystals, the distribution of tritium in the T⁺ state increased from 58% to 81% with increasing neutron fluence from 2.5×10¹⁶ cm^–2 to 6.3×10¹⁷ cm^–2.     

On the reactivity of supported zirconium organic catalysts in the polymerization of ethylene

The ethylene polymerization with tetrabenzyl zirconium displays a higher concentration of active centres on catalysts obtained by supporting of the organometallic compound on alumina or silica-alumina carriers than by activation without supporting. The active centres of the supported catalysts possess different polymerization reactivity. At the beginning of the polymerization in the presence of monomer, these active centres are formed from a small amount of the stable surface compounds originated in the carrier impregnation. The maximum polymerization rate depends on the pretreatment, the loading and the porosity of the carrier. The more active these centres, the quicker they lose their activity. A relation was found between a chemical deactivation reaction and the concentration of the hydroxyl groups remaining on the catalyst after impregnation. Addition of hydrogen or butyllithium can change the polymerization in a different manner. The addition of butyllithium causes an increase in the number and the reactivity of the active centres and a suppression of the chemical deactivation.     

On the possibility of complex formation of Group IIIB organic compounds with molecular oxygen

The likelihood of the formation of R₃E·O₂ complexes (E is an element of Group IIIB) in R₃E/O₂ systems has been shown experimentally and theoretically. The most probable energetic parameters, structure, problems of stability are discussed.     

On the trail of CrO2Cl2 in its reactions with organic compounds

The simple metal oxo compound chromyl chloride, CrO2Cl2, displays a very complex reactivity with respect to alkanes, olefins, alcohols, and epoxides. Synergetic investigations applying various techniques and methods have only recently led to an understanding of the key steps in the corresponding mechanisms, which are representative for more complex systems. Product formation seems to be largely determined by radical reactions initiated by this d0-metal compound.     

Selective dehalogenation and hydrogenation of compounds in adsorption layers with tritium gas

Selective dehalogenation and hydrogenation were observed in treating the corresponding precursors supported on a heterogeneous carrier with tritium gas. This technique was used to obtain tritium-labeled 3′,3,5-triiodothyronine, dihydrofusicoccin terpenoid (DHF), and 3-(piperidine-4-yl)-1,4-dihydroquinazoline-2-on with a molar radioactivity of 0.76, 2.3, and 6.5 PBq/mol, respectively.