Radiochemistry最新文献

A novel 12-step procedure was developed for preparing methyl 14-isocyano-3-methyltetradecanoate. “2+1_B” tricarbonyl complexes [^99mTc(CO)₃(N^N)CN(CH₂)₁₁CH(CH₃)CH₂COOMe]⁺, where N^N = 2,2'-bipyridine (bipy) or 1,10-phenanthroline (phen), were prepared by the reaction of [^99mTc(CO)₃(N^N)(H₂O,EtOH)]⁺ with methyl 14-isocyano-3-methyltetradecanoate in aqueous ethanol. The formation of technetium-99m complexes was confirmed by HPLC, and the partition coefficient (n-octanol/water) of these complexes was measured.

Synthesis, IR spectroscopic, and X-ray diffraction studies of R[UO₂(mia)₃]₂·2Hmia·4H₂O crystals, where R = Sr²⁺ (I) or Ba²⁺ (II), and mia is the monoiodacetate ion CH₂ICOO⁻, have been carried out. The [UO₂(mia)₃]^– complexes correspond to the crystal chemical formula A(B⁰¹)₃, where A = UO₂²⁺, B⁰¹ = mia. It has been established that a common feature of I and II is the presence of trinuclear electrically neutral clusters {R[UO₂(mia)₃]₂(Hmia)₂(H₂O)₂}. At the centers of the clusters there are trigonal RO₈ dodecahedra; half of their oxygen atoms belong to four different mia anions of two [UO₂(mia)₃]^– complexes. In addition, each R atom coordinates the oxygen atoms of two water molecules and the carbonyl oxygen atoms of two Hmia molecules. Using the method of molecular Voronoi–Dirichlet polyhedra, an analysis of noncovalent interactions in the structure of I was carried out.

The effect of the ionic liquid, 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide, on the extraction of lanthanides(III) from nitric acid solutions with phosphoryl-containing podands (2-(2-diphenylphosphoryl)-4-ethylphenoxy)methyl)diphenylphosphine oxide (1), (2-(2-diphenylphosphoryl)-4-ethylphenoxy)ethyl)diphenylphosphine oxide (2), and 2-[2-(diphenylphosphoryl)-4-ethylphenoxy]-N,N-dioctylacetamide (3) was studied. The stoichiometry of the extracted complexes was determined. The efficiency of extraction of lanthanides(III) with solutions of compounds 1–3 in dichloroethane from nitric acid solutions increases in the order 3 < 2 < 1. It has been established that, when replacing dichloroethane with an ionic liquid as a diluent, the extraction efficiency enhances. The magnitude of this effect decreases in the series of compounds 3 > 2 > 1. In the case of compound 1, the replacement of dichloroethane with an ionic liquid as a solvent is accompanied by a decrease in the extraction of lanthanides(III) at [HNO₃] > 1.5 M.

The possibility of introducing tritium into dexamethasone and dexamethasone phosphate using the thermal activation method was demonstrated. The affinity of ligands for glucocorticoid receptors has been successfully assessed using labeled compounds.

The results obtained in the initial step of studying the effect of external proton irradiation on the properties and structure of simulated borosilicate and aluminophosphate glasses and of internal irradiation on the active glass arranged in the repository of the radiochemical plant of the Mayak Production Association are reported. These results show that the glass melting technologies used at the Mayak Production Association can reliably ensure the environmental safety of the glass incorporating the high-level waste.

Radiation resistance of diesel fuel with the addition of various percentages of toluene was studied. The experiments were carried out for a long time to study the postpolymerization processes. The kinetics of processes during irradiation of pure diesel fuel was studied at the temperature T = 20°C and dose rate P = 0.07 Gy/s in the range of absorbed doses D = 15–150 kGy, and a mixture of toluene with diesel fuel was irradiated within the absorbed dose range D = 24–90 kGy at a toluene concentration of 1, 3, and 5 vol %. Analysis by gas chromatography–mass spectrometric (GC/MS) was performed, and the density, viscosity, and iodine number of the diesel fuel before and after irradiation at various absorbed doses were determined. The kinetics of postpolymerization processes after the end of irradiation shows that the rate of the process and its share in the total polymerization depend on the irradiation time, initial mixture density, and dose. By adding additives (antirads), one can choose the composition of diesel fuel that will better withstand radiation exposure. It is necessary to find the optimal concentration of toluene in the composition of diesel fuel, at which the viscosity and density will not change with an increase in the absorbed dose.

Activated carbon (AC) decorated by silver (Ag/AC) and silica (Ag-Si/AC) nanoparticles was used in the treatment of crude phosphoric acid to remove some inorganic and organic impurities. The effect of time, solid/liquid ratio, temperature, and hydrogen peroxide dose on the phosphoric acid treatment was examined. The catalytic activity and uranium uptake efficiency are improved when carbon structures contain Ag and Si nanoparticles. Uranium and organic matter are removed from crude phosphoric acid more efficiently when crude phosphoric acid is treated with activated carbon decorated by silver (Ag/AC) and silica (Ag-Si/AC) nanoparticles with catalytic wet peroxide oxidation, compared to the treatment with activated carbon only, and at high acid concentration (8 M) and solid/liquid mass ratios (0.001), using unsurpassed H₂O₂. The higher removal efficiencies of uranium and organic matter (OM) were attributed to the increased adsorptive interactions between the AC-based adsorbent surfaces and the OM and uranium species.

The content of global ^239,240Pu in Caspian sea water (1996–2056) was calculated using the sorption–diffusion model of the radionuclide uptake by bottom sediments with the distribution coefficient K_d = 50 × 10³ and diffusion coefficient D = 0.1 × 10^–7 cm²/s. The ^239,240Pu global fallout on the sea was assumed to be equal to the experimental value for the mid-latitude belt of Russia, 60 Bq/m². At the plutonium fallout density on the sea surface of 58 Bq/m², its inventory in the sea Q as of the year 1964 is 21.9 TBq. In 1996, the experimentally determined ^239,240Pu concentration in Caspian sea water was ~20 μBq/L, and the calculation by the model gives 17.8 μBq/L. During the ~30-year migration of global ^239,240Pu, about 93% of the radionuclide passed from the aqueous phase to bottom soils. According to the calculations, the ^239,240Pu concentration in the seawater in the period 1996–2056 will decrease from 17.8 to 10.5 μBq/L, and the ^239,240Pu inventory in the seawater, from 6.3 to 3.7%, of the fallout value. The results were verified using an independent method for ⁹⁰Sr monitoring in Caspian sea water and determining the ^239,240Pu/⁹⁰Sr concentration ratio in the water. The results of estimating the ^239,240Pu concentrations in the seawater (2017–2020) by these two methods reasonably agree with each other.

The possibility of using ferrocyanide sorbents NPF-HTD, NPF-C, and T-35 for cesium concentration in the method of ¹³⁷Cs determination in natural and waste waters has been investigated. Differences in sorption characteristics of sorbents and conditions of cesium concentration to achieve a chemical yield of 98–99% in the concentrate have been revealed. A variable method for determination of ¹³⁷Cs in natural and waste waters has been developed, taking into account the ratio of sample volume and sorbent mass in the column, the efficiency of ¹³⁷Cs detection, and the time of concentrate measurement to achieve the minimum detectable activity of ¹³⁷Cs in the sample of 0.001–0.01 Bq/L. The method was tested for determination of ¹³⁷Cs in waters of natural reservoirs and rivers in the territories of Sverdlovsk oblast and Chelyabinsk oblast, as well as waters of monitoring wells in the territories of long-term storage and disposal of radioactive waste. The data on the composition of river and reservoir waters are presented, and the dependence of the cesium chemical yield into the concentrate on the concentration of macrocomponents in samples is shown.

Two new complex Np(VI) nitrates with carbamoylurea (biuret) and with a derivative of terpyridine (Ph-Terpy) of the composition [(NpO₂)(biuret)(NO₃)₂] (I) and [H₂(Ph-terpy)(NO₃)]₂[NpO₂(NO₃)₄] (II) have been synthesized and structurally characterized. The coordination environment of Np atoms in compounds are distorted hexagonal bipyramids with “yl” oxygen atoms in apical positions. The equatorial plane of the bipyramid in complex I is formed by oxygen atoms of two bidentate NO₃^– anions and an electroneutral ligand. The equatorial plane of the bipyramid in II is formed by oxygen atoms of two bidentate and two monodentate NO₃^– anions. The twice protonated Ph-terpy is the basis of the complex cation [H₂(Ph-terpy)(NO₃)]⁺.