Principal relationships of the heterogeneous catalytic oxidation of benzene and its derivatives

The results of investigations into the processes involved in the heterogeneous catalytic oxidation of benzene and its derivatives at the L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, are summarized. The mechanisms of the full and partial oxidation of benzene, toluene, and their halogen derivatives are discussed. L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, Kiev. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 34, No. 3, pp. 133–147, May–June, 1998.     

Energetics of electron processes in semiconductor photocatalytic systems

The energetics of electron processes in photocatalytic systems based on dispersed semiconductors, their nanocomposites and heterostructures are examined. Methods for the approximate estimation and quantitative determination of their energetic characteristics are evaluated and energy diagrams of photocatalytic systems based on semiconductor nanocomposites and their heterostructures are plotted. Analysis of the diagrams permits the elucidation of the nature of their photocatalytic effects in redox reactions. L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Prospekt Nauki, Kiev 03039, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 36, No. 2, pp. 69–89, March–April, 2000.     

Single-stage polyepoxyacrylate analog formation in thin films in contact with a substrate

IR spectroscopy has been applied to the photo-initiated polymerization of a model system containing an ED-20 epoxide resin and methacrylic acid, which has been used in thin layers between windows of KRb or teflon. The KRb substrates inhibit cationic polymerization and alter the ratio of the rates of the cationic and radical processes, which affects the structure of the final product. Institute for Macromolecular Compound Chemistry, National Academy of Sciences of Ukraine, 48 Kharkov Shosse, Kiev, Ukraine 253160. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 34, No. 1, pp. 58–61, January–February, 1998.     

Activation and oxidation of carbon-based materials impregnated with potassium carbonate

Details are considered on the porous structure and oxidation of activated carbon-fiber tissue and anthracite in the presence of potassium carbonate. Specimens impregnated with K₂CO₃ show those processes of structuring and oxidation substantially accelerated. The time and temperature parameters required to produce highly porous sorbents and cation exchangers based on these carbon materials are much lower than those for the usual activation-oxidation process involving atmospheric oxygen. Institute for Sorption and Endoecology, National Academy of Sciences of Ukraine, 13 ul. Generala Naumova, Kiev 252164, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 35, No. 5, pp. 306–310, September–October, 1999.     

Crystallization kinetics of zeolite-like phosphates AIPO4-5 and SAPO-5

We show that the crystallization rate of isostructural zeolite-like phosphates AlPO₄-5 and SAPO-5 is considerably higher than for zeolites and polysilicates. We analyze the kinetic and energy parameters, taking into account the high structural lability of aluminophosphates, the effect of limiting processes of dissolution of the original pseudoboehmite and conversion of the intermediates, and also isomorphic inclusion of silicon atoms. L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Nauki Prospekt, Kiev 252039, Ukraine. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 33, No. 3, pp. 184–187. May–June, 1997.     

Electrochemically activated insertion of fluoroalkyl groups into organic and inorganic substrates

This article summarizes and correlates information on electrochemical processes of fluoroalkylation of organic and inorganic compounds, based on cathodic and anodic activation of fluoroalkyl halides R_FHal. The electrochemical behavior of R_FHal under various conditions is examined, as well as the interaction of fluoroalkyl radicals, generated in cathodic reduction of R_FHal, with various nucleophiles (thiophenolates, phenolates, anionic nitrogen-containing heterocycles, their methylene bases, etc.); with ethylenic, acetylenic, and carbonyl compounds; and with “small” molecules (CO₂, O₂, SO₂, CS₂). Possible mechanisms of such processes are examined critically, along with prospects for further development of this new direction in research. L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Prospect Nauki, Kiev 252039, Ukraine. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 35, No. 1, pp. 17–34, January–February, 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.     

Complexing sorbents based on dispersed minerals for recovery of heavy metal ions from aqueous solutions

We have obtained sorbents for recovery of heavy metal ions from aqueous solutions by modification of kaolinite and metakaolinite, aluminum oxyhydroxide and aluminum hydroxide by polyphosphates. Using sorption of Ni²⁺, Co²⁺ and Cr³⁺ as an example, we have shown that the sorbents have high sorption capacity and distribution coefficient with respect to heavy metal ions. We have studied the composition of the complexes formed. We have developed methods for granulation of the sorbents with a binder and for regeneration of the sorbents. A. V. Dumanskii Institute of Colloid Chemistry and Chemistry of Water, National Academy of Sciences of Ukraine, 42 Bul'var Akademika Vernadskogo, Kiev-142 252680, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 35, No. 3, pp. 167–170, May–June, 1999.     

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.     

Catalytic properties of the carbides of transition metals in oxidation reactions

It was shown that the carbides of transition metals are effective catalysts of oxidation reactions on account of their metal-like nature, combined with their high chemical and thermal stability. The results from systematic investigations into the catalytic characteristics of the carbides in the oxidation of hydrogen, carbon monoxide, and ammonia and in the oxidative coupling of methane (OCM) are examined. The first two reactions are total oxidation processes, and the oxidation of ammonia is a selective oxidation process. The oxidative coupling of methane is a heterogeneous-homogeneous process and represents a prospective method for the direct transformation of methane into higher hydrocarbons. 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. 5, pp. 265–281, September–October, 1998.     

The C−C bond chain termination mechanism in Fischer-Tropsch synthesis on a Co/SiO2·Zr(IV) catalyst

Two forms of chain termination are considered: on account of hydrogenation of metal-carbon bonds in surface intermediates and because of the elimination of hydrogen, which leads to the formation of α-olefins as primary products. 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. 44–49, January–February, 1999.     

Sorption of heavy-metal ions and radioactive cesium by “Ultrasorb” composite sorbent

Data are given on the sorption of heavy-metal ions (Fe³⁺, Co²⁺, Cd²⁺, Pb²⁺, Zn²⁺, Cu²⁺ and Ni²⁺) and radioactive isotope¹³⁷Cs from Ringer salt solution by Ultrasorb composite sorbent, which has two components: the modified clay mineral palygorskite (palygorskite-M) and a modified fibrous carbon sorbent of AUT-M type (UVM-Ts). Selectivity series have been determined for the sorption of these toxic metals on the basis of the calculated distribution coefficients K_d under standard conditions. It is shown that the properties of the components combine well in the material, and it is proposed for use as a treatment agent (enterosorbent) having a selective action in the treatment of diseases due to the accumulation of heavy metals and radionuclides in the body. Institute for Sorption and Endoecological Problems, National Academy of Sciences of Ukraine, 13 ul. Generala Naumova, Kiev 03164, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 36, No. 1, pp. 53–57, January–February, 2000.     

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.     

Influence of irradiation conditions on the photochemical one step formation of analogs of polyepoxyacrylates

Simultaneous photoinitiated polymerization of epoxide resins and methacrylic acid in the presence of triphenylsulfonium hexafluorophosphate has been studied. Reaction of the carboxyl group with epoxide has been observed in addition to homopolymerization. The extent of this interaction depends on the radiation regime. Institute of Macromolecular Chemistry, National Academy of Sciences of the Ukraine, 48 Khar’kovskoe Shosse, 253160 Kiev, Ukraine. Translated from Teoreticheskiya i éksperimental’naya Khimiya, Vol. 33, No. 4, pp. 252–255, July–August, 1997.     

α-Effect of hydroxylamine in the transfer of a toluenesulfonyl group in water—Dimethyl sulfoxide mixtures

A kinetic and thermodynamic analysis of the reactions of hydroxylamine with aryltoluenesulfonates in H₂O-DMSO mixtures (0–90 vol.% DMSO) indicated that the neutral and anionic forms of hydroxylamine are strong α-nucleophiles, and the magnitude of the α-effect shows an asymmetric bell shape depending on the DMSO content. This phenomenon is interpreted. 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. 2, pp. 83–88, March–April, 1999.     

Synthesis and properties of inclusion compounds: Zeolites containing encapsulated transition-metal complexes

Published data and original results are surveyed on the synthesis, structure, and properties of a new type of inclusion compounds based on porous substances (zeolites) containing encapsulated transition-metal complexes. 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. 4, pp. 199–214, July–August, 1999.     

Titanium-containing silica mesoporous molecular sieves

An analysis was made of the conditions for the synthesis of titanium-containing mesoporous silica molecular sieves and their effect on the stereochemical structure, the coordination of the titanium, and the catalytic characteristics. L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Prospekt Nauki, Kiev 03039, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 36, No. 3, pp. 135–158, May–June, 2000.     

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.     

The α-effect of oximate ions and solvent effect in the transfer of the toluenesulfonyl group in aqueous dimethylsulfoxide

The kinetic behaviour of oximate ions was studied in the transfer of the toluenesulfonyl group in aqueous dimethylsulfoxide (0–95 vol.% DMSO). The solvation effects of the solvent are a factor controlling the nucleophilicity and magnitude of the α-effect of the oximate ions. 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. 36, No. 1, pp. 30–35, January–February, 2000.     

Local-center phosphorescence in doped naphthalene and octadeuteronaphthalene crystals

Phosphorescence measurements have been made on both naphthalene and octadeuteronaphthalene crystals at 4.2-10 K. The emission spectra are of doublet type. The impurity levels are accompanied by local states. A method of identifying them is proposed. The energy transfer between the various radiating centers is discussed. Physics Institute, National Academy of Sciences of Ukraine, 46 Nauki Prosp., Kiev-22, Ukraine 252650. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 34, No. 1, pp. 53–57, January–February, 1998.