Dynamic state of water and the adsorption of surfactants in systems consisting of water, surfactant, and a solid sorbent

A study has been made of the influence of solid components on the dynamic state of water molecules in systems consisting of water, a surfactant, and a solid sorbent. An attempt has been made to establish the relationship between the changes in dynamic state of water molecules and adsorption phenomena in the system. A. V. Dumanskii Institute of Colloid Chemistry and the Chemistry of Water, National Academy of Sciences of Ukraine, 42 Academician Vernadskii Prosp., Kiev-142, Ukraine 252680. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 34, No. 1, pp. 19–22, January–February, 1998.     

Investigation of the mechanism of methane formation in the fischer-tropsch synthesis on a Co/SiO2·ZrIV catalyst

Methane is formed in the Fischer-Tropsch synthesis under real conditions both through intermediates leading to chain propagation and by hydrogenation of surface carbon. L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, Prospekt Nauki 31, 252039 Kiev, Ukraine. Translated from Teoreticheskaya i éksperimental’naya Khimiya, No. 1, pp. 41–43, January–February, 1996.     

Mechanisms of the coupling of one-and two-electron reactions in chemical and biochemical processes

The mechanisms of chemical and biochemical reactions in which one-electron stages ae coupled with two-electron stages are examined. The mechanisms of the coupling of the one- and two-electron stages in the electron-transport systems of the living cell are discussed on the basis of an analysis of chemical models. Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Sciences of Ukraine, 1 Murmanskaya ul., Kiev 253094, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 35, No. 3, pp. 133–144, May–June, 1999.     

Modern approaches to the construction of highly efficient nucleophilic systems

In this review we present a summary and correlation of research results obtained in several different approaches aimed at increasing the efficiency and selectivity of nucleophilic reactions, namely the α-effect in aqueous media and specific interactions in nontraditional systems such as “melts” of salts, microemulsions, micelles, and liquid/liquid and liquid/solid interfacial systems. L. M. Litvinenko Institute of Physical Organic and Coal Chemistry, National Academy of Sciences of Ukraine, 70 R. Lyuksemburg ul., Donetsk 340114, Ukraine. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 35, No. 1, pp. 1–16, January–February, 1999.     

Peculiarities of the mechanism of chlorotropic and conformational isomerism in a series of chloromethyl isocyanates

The thermodynamic and kinetic stability of chlorotropic isomers in a series of chloromethyl isocyanates Cl_3−nH_nC−N=C=O, where n=0, 1, 2, has been shown by quantum chemical calculations, using the MNDO method, and by³⁵Cl NQR spectroscopy. The phase transformations of two polymorphic modifications of N-chlorocarbonyl dichloride, which is a stable iminocarbonyl form of trichloromethyl isocyanate with small conformational activation barriers, have been studied. Institute of Bioorganic and Petrochemistry, National Academy of Sciences of Ukraine, 1 Murmansk ul., Kiev-94 252660, Ukraine. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 34, No. 3, pp. 164–169, May–June, 1998.     

The effect of nitrogen in the carbon matrix on the donor-acceptor and catalytic activity of activated carbons in electron transfer reactions

The effect of the position of the nitrogen atoms in the π-conjugated system of condensed rings on the width of the forbidden band of carbon as a semiconductor was investigated by the semiempirical AM1 molecular orbital method. A correlation was found between the position of the nitrogen atoms in nitrogen-containing carbon, the catalytic activity in electron transfer reactions, and the width of the forbidden band of such semiconductors. Institute of Sorption and Problems of Endoecology, National Academy of Sciences of Ukraine, 13 Generala Naumova ul., Kiev 252680, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 35, No. 6, pp. 338–342, November–December, 1999.     

Reactivity of macroheterocycles with respect to sulfamic acid

It has been established, on the basis of the formation of a 1∶1∶1 inclusion compound of 18,19-benz-1,16-diaza-4,7,10,13-tetraoxoeicosa-17,20-dione with sulfamic acid and water from the interaction of 11–20-membered macrocyclic oxyethyleneamides of phthalic acid with sulfamic acid, that 18–20-membered oxyethylene macrocycles containing six oxygen donor atoms in the macrocycle are effective in the formation of “host-guest” complexes. Physicochemical Institute for the Preservation of the Environment and Mankind, Ministry of Education and Ukraine National Academy of Sciences of Ukraine, Odessa 270100. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1571–1573 November, 1997.     

A study of the mechanism of the reaction of 1,3-dioxanes with derivatives of acyclic boronic acids using the AM1 method

Estimation of the energy of intermediate compounds in the reaction of 1,3-dioxanes with acyclic derivatives of boric acids by the AM1 method showed that the reactivity of the initial heterocycles which were converted into 1,3,2-dioxaborinanes was determined by the relative stability of the bipolar structure in the stage preceding, the formation of the endocyclic B−O bond. A. V. Bogatskii Physical Chemical Institute, National Academy of Sciences of Ukraine, 86 Lyustdorfskaya Doroga, Odessa 65080, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 36, No. 4, pp. 218–221, July–August, 2000.     

The electronic structure of the bases of cyanine dyes and the barriers of their conformational transformations

The equilibrium geometry and electronic transitions of cyanine dyes and their bases and also the barriers to rotation of the terminal groups in the ground and excited states were calculated in the AM1 approximation. It was found that in contrast to the cyanine dyes the bases are closer in electronic structure to conjugated systems of the polyene type. The calculated barriers to rotation are significantly higher in the bases than in the dyes. Institute of Organic Chemistry, National Academy of Sciences of Ukraine, 5 Murmanskaya ul., Kiev 253094, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 35, No. 4, pp. 222–226, July–August, 1999.     

Chemisorption of N-vinyl-2-pyrrolidone on the surface of hydridosilica gel

The solid phase hydrosilation of N-vinyl-2-pyrrolidone by≡Si−H bonds immobilized on a silica gel surface has been investigated. Institute of Surface Chemistry, National Academy of Sciences of Ukraine, 31 Prospekt Nauki, Kiev 252022, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 35, No. 4, pp. 236–239, May–June 1999.     

Effect of titanium on the structure and properties of mesoporous MCM-41 molecular sieves

Mesoporous MSM-41 titanium silicate molecular sieves with high titanium content were synthesized. The hexagonal structure along with high specific surface and pore volume are retained up to Si/Ti≥5. L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Prospekt Nauki, Kiev 252039, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 35, No. 3, pp. 177–182, May–June, 1999.     

Effect of rehydration on the porosity of MCM-41 mesoporous molecular sieves

In distinction from aluminosilicates, the porosity of the detemplated silicous MCM-41 is significantly reduced after several cycles of dehydration-rehydration. The stability of Si-MCM-41 is not changed by absorption-desorption of nonpolar hexane. An explanation is proposed for the effect of rehydration on the porosity of MCM-41. L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Prospekt Nauki, Kiev 252039, Ukraine. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 35, No. 1, pp. 50–55, January–February, 1999.     

Effect of the extent of oxidation of activated carbons by O2 and HNO3 on the acidity and composition of surface functional groups and their ion-exchange properties

We have studied the effect of the extent of oxidation of carbon sorbents KAU and SKN by different oxidizing agents on the acidity of the surface functional groups and their qualitative composition, and also the selectivity of sorption of copper and lead ions from drinking water under static and dynamic conditions. We propose a mechanism for the formation of different types of acid groups on the carbon surface during its progressive oxidation. Institute for Sorption and Problems of Endoecology, National Academy of Sciences of Ukraine, 32/34 Akademika Palladina Prosp., Kiev-142, Ukraine 252680. Loughborough University, Loughborough, Great Britain. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 34, No. 1, pp. 27–31, January–February, 1998.     

Kinetics and mechanism of the reaction of 1-benzoyloxy-4-[4-(dimethylamino)styryl]pyridinium tetrafluoborate with trimethyl-benzylammonium chloride in acetonitrile

The reaction of 1-benzoyloxy-4-[4-(dimethylamino)styryl]pyridinium tetrafluoborate with trimethylbenzylammonium chloride in acetonitrile takes place with the formation of an ion pair of 1-benzoyloxy-4-[4-(dimethylamino)styryl]pyridinium chloride, the slow decomposition of which to the σ adduct is rate-determining. The equilibrium constants of the individual steps of formation of ions from the ionogens PhCOCl and DASPO are determined. L. M. Litvinenko Institute of Physical Organic Chemistry and Carbon Chemistry, National Academy of Sciences of Ukraine, 70 Lyuksemburg ul., Donetsk 341114, Ukraine. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 34, No. 3, pp. 148–152, May–June, 1998.     

Influence of reactant structure on composition and stability of adducts of bis-macrocyclic complexes of copper(II) with aliphatic α,ω-diamines

On the basis of spectrophotometric measurements, constants have been determined for adduct formation between bis-macrocyclic complexes of copper(II) and aliphatic diamines. For these systems, the influence of reactant structure on the specific features of complexation has been established. L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of the Ukraine, 31 Nauka Prospect, Kiev 252039, Ukraine. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 33, No. 2, pp. 83–87, March–April, 1997.     

Kinetics and mechanism of the decomposition of cumyl hydroperoxide in the presence of 2-mercaptobenzimidazole

2-Mercaptobenzimidazole reacts with cumyl hydroperoxide to give radicals. This accounts for the initiating effect of this compound in the autoxidation of isopropylbenzene and ethylbenzene. On the other hand, 2-mercaptobenzimidazole is a weak inhibitor in the low-temperature initiated oxidation of alkylbenzenes. Donetsk State University, 24 Universitetskaya St., 340055 Donetsk, Ukraine. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 33, No. 1, pp. 44–48, January–February, 1997.     

Mechanism of reactions of photocatalytic synthesis of chlorohydrins

A mechanism of photocatalytic synthesis of chlorohydrins from olefins and peroxo complexes of titanium (IV) is proposed. It consists of formation of radical-containing complexes, their reactions with olefins, and decomposition of the α-oxides obtained by hydrogen chlorides. L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Prosp. Nauki, 252039 Kiev, Ukraine. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 33, No. 1, pp. 17–21, January–February, 1997.     

Separation of C1–C4 hydrocarbon gases on impregnated liquid membranes

Diffusion plays an important role along with complexation in the separation of C₁–C₄ hydrocarbon gases on copper-containing impregnated liquid membranes. The partition factor changes as the process goes from nonsteady-state to steady-state. L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Prospekt Nauki, Kiev 252039, Ukraine. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 34, No. 3, pp. 191–195, May–June, 1998.     

Photocatalysis of reaction of hydrogen production by cadmium and zinc sulfide nanoparticles incorporated into silicate matrices

Novel nanostructural materials have been prepared, their diffuse reflection spectra have been studied, and their electrophysical characteristics (width of forbidden band, position of conduction band) have been evaluated. It has been established that these materials have high photocatalytic activity, and the factors influencing this activity have been examined. L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of the Ukraine, 31 Nauka Prospect, 252039 Kiev, Ukraine. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 33, No. 1, pp. 32–35, January–February, 1997.     

Influence of the composition of Co-containing perovskites on their catalytic properties in the conversion of methane into higher hydrocarbons in non-stationary conditions

The oxidative coupling of methane in a periodic regime was studied using Co-containing perovskites as solid oxidants. Partial substitution of strontium with alkali metals in the perovskite SrCoO₃ increased the activity and selectivity of the catalyst with respect to higher hydrocarbons. The substituted catalysts continued to work after many oxidation-reduction cycles. L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Prospekt Nauki, Kiev 252039, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 36, No. 1, pp. 47–52, January–February, 2000.