Some aspects of determination of radionuclides at the former Semipalatinsk Nuclear Test Site

There is investigated a radionuclide composition of the soil samples, selected in various parts of former Semipalatinsk Nuclear Test Site (SNTS). The gamma-spectrometric method was used for determination of¹³⁷Cs and²⁴¹Am. For determination of⁹⁰Sr and isotopes of plutonium a radiochemical separation was used. The results of determinations show a distinction in distribution of radionuclides on depth for various investigated areas and for various size fractions of surface layers. The study of the size fractions has shown an enrichment of a magnetic faction by²⁴¹Am.     

Aggregation of amphiphilic aminomethylated calix[4]resorcinarenes and the nonionic surfactant Triton-X-100 in organic solvents

Aggregation and intermolecular interactions of amphiphilic calix[4]resorcinarene (1), aminomethylated calix[4]resorcinarenes (AMC 2—7) with different structures of the upper rim (including the oxazine structure in 6 and 7) and hydrophobic substituents on the lower (2—5), upper (6), or both rims (7) in the absence and in the presence of the nonionic surfactant Triton-X-100 (8) and p-nitrophenol (9) in chloroform and 1,4-dioxane were studied by permittivity measurements and 2D ROESY ¹H NMR technique. The tendency of amphiphilic derivatives 1—7 toward self-aggregation and mixed aggregation with surfactant 8 primarily depends on the nature of both the solvent and the polar groups on the upper rim of calixarenes. In chloroform, AMC—8 aggregates show interactions of the methyl and methylene groups of the hydrophobic substituents of AMC with the ethyleneoxy fragments of surfactant 8, while in stable intermolecular complexes of 5 and 6 with compound 9, the methylene groups of the long-chain radicals of the AMC strongly interact with the aromatic protons ortho to the hydroxy group of 9. In 1,4-dioxane, calix[4]resorcinarenes 1 and 5 are bound in stable solvates, which prevents them from forming aggregates and mixed micelles.     

Phosphorylation of alkylated poly(ethyleneimine) in chloroform in the presence of cetyltrimethylammonium bromide and calix[4]resorcinarene

The phosphorylation of alkylated poly(ethyleneimine) with 4-nitrophenyl bis(chloromethyl)phosphinate in chloroform in the presence of cetyltrimethylammonium bromide (CTAB), calix[4]resorcinarene (CR), or their mixture was studied by UV spectrophotometry. The catalytic effect of CTAB and CR on the process of polymer phosphorylation was shown to depend on the concentration of the surfactant and poly(ethyleneimine) in solution. The catalytic effect of the system is ascribed to the formation of poly(ethyleneimine)-CTAB, poly(ethyleneimine)-CR, and poly(ethyleneimine)-CTAB-CR mixed aggregates. Their existence was confirmed by the methods of light scattering and UV spectroscopy. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 918–923, May, 2007.     

Aggregation and catalysis in a nonionic surfactant-polyethylenimine-chloroform system

The formation of polymer-colloid complexes (PCCs) of hydroxybenzylated polyethylenimines (PEIs) with poly(ethylene glycol-600) monolaurate (PM) in chloroform is established through dielcometric titration, light scattering, and viscometry. The effect of PCC on the PEI reactivity in phosphorylation with 4-nitrophenyl bis(chloromethyl)phosphinate is studied with spectrophotometry. It is found that the character of aggregates and the degree of their influence depend on the PM-to-PEI concentration ratio, polymer structure, and reaction temperature.     

Supramolecular systems formed by calix[4]resorcinarenes and surfactants in chlorophorm

Capacity titration and ¹H NOESY 2D NMR were applied to investigation of intermolecular interactions and aggregation of amphiphilic calix[4]resorcinarenes (CRA 1, 2) modified with 1,2,4-triazine (1) and oxazine (2) functions in chloroform in the presence of cationic (3) and non-ionic (4) surfactants (SAA). Critical concentrations of micelle formation (CMC) indicate that the ability of CRA 1, 2 to form supramolecular aggregates like micelles or hybrid micelles with SAA 3, 4 only weakly depends on the constitution of CRA functional groups. In the case of the hybrid micelles, when CMC are defined by the nature of surfactants 3 or 4, the methyl and methylene groups of the hydrophobic fragments (CRA 1, 2) were found to interact with the hydroxy groups of SAA 3 and ethylene oxide moieties of SAA 4.     

Complexation of 1-hexadecyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide with nickel nitrate in acetone

The complexation of 1-hexadecyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide with Ni(II) nitrate in acetone is studied by means of spectrophotometry (the Job–Ostromisslensky technique and molar ratios). The formation of 3: 1 and 1: 1 ligand: metal complexes is established and confirmed by mathematical modeling. The stability constants of the complexes and the change in the Gibbs free energy are determined.     

Specific features of the radiolysis of water and aqueous solutions of H2 and O2 by mixed n,γ-radiation with a high portion of the neutron component

A previously unknown feature of the kinetics of the radiolysis of water and hydrogen, oxygen, and hydrogen peroxide solutions has been discussed. By calculation, it has been revealed that concentration oscillations of the radiolysis products can appear during irradiation of the solution with fast neutrons or mixed n,γ-radiation with a high portion of the neutron component. The period and amplitude of the oscillations depend on the temperature, the dose rate, and the ratio of n/γ radiation components. It has been shown that oscillations cannot be excited during γ-radiolysis under any conditions. It is suggested that the mechanism of the oscillations is similar to the Belousov-Zhabotinsky reaction mechanism. A chain reaction proceeds in the irradiated system, in which the reactants H₂O₂ (“reducing agent”), “oxidizing agent” OH radicals initiating the chain, and the “catalyst” are introduced from the outside. Hydrogen molecules produced by the action of radiation play the role of the “catalyst”, and H₂O molecules formed in the secondary reactions are the “deactivated form of the catalyst”. Hydrogen atoms and hydrated electrons propagate the chain. Oxygen formed in both spurs and the secondary reactions is the “inhibitor” terminating the chain reaction.     

On orthorecursive expansions in terms of a chain of systems

Doklady Mathematics -     

Aggregation behavior and catalytic properties of systems based on aminomethylated calix[4]resorcinarenes and poly(ethylene) imines

Self-assembling in systems poly(ethylene) imine-aminomethylated calix[4]resorcinarene-water-DMF (30 vol%) and catalytic properties of these compositions in hydrolysis of 4-nitrophenylbis (chloromethyl)phosphinate are studied. Critical concentrations of association, aggregates radii, and kinetic parameters of the reaction are established.     

Catalytic properties of polymer-colloid complexes based on polyethyleneimines and mono- and diquaternized 1,4-diazabicyclo[2.2.2]octane derivatives in the hydrolysis of phosphorus acids esters

Russian Chemical Bulletin - It is established by spectrophotometry that polyethyleneimines, mono- (MQD) and diquaternized (DQD) hexadecyl derivatives of 1,4-diazabicyclo[2.2.2]octane, and mixed...