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 the composition of the reaction mixture and the synthesis conditions on the formation of mesomorphous substances in the presence of glucose oxidase

The possibility of synthesizing mesoporous substances in silicate and aluminosilicate systems in the presence of combinations of glucose oxidase and cetyltrimethylammonium bromide has been demonstrated. Highly crystalline mesoporous molecular sieves of type MCM-41 with a high aluminum content were obtained from the aluminosilicate system with a reaction mixture pH close to neutral. 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, 190–193, May–June, 1999.     

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.     

Kinetics of the growth of the oxide layer during anodic oxidation of aluminum

Experimental plots of anode current density against time obtained for various electrolytes over a temperature range from 5 to 60°C have been compared with a theoretical model which describes the kinetics of the growth of the oxide film during anodic oxidation of aluminum. It is concluded from differences in the kinetic parameters for ammonium benzoate and ammonium adipate that the oxidative destruction of the corresponding carboxylate anion is involved in a rate determining step of the process. V. I. Vernadskii Institute of General and Inorganic Chemistry, Ukraine Academy of Sciences, 32/34 Academician Palladin Prosp., 252680 Kiev-142, Ukraine. Translated from Teoreticheskiya i éksperimental’naya Khimii, Vol. 33, No. 1, pp. 58–61, January–February, 1997.     

Sigmatropic mechanism of the chlorotropic isomerization of phosphazopentachloroethane

The sigmatropic and dissociative-recombination mechanisms of the chlorotropic isomerization of benzodioxachlorophosphazopentachloroethane and its 1:2 solvate with chloroform have been studied by the MNDO-PM3 method in the supermolecular approximation. It is observed that the thermodynamically more stable chlorotropic isomer corresponds to the phosphorane structure with axial-equatorial disposition of two chlorine atoms and the two oxygen atoms in the dioxaphosphole ring, in complete agreement with literature data on teh³⁵Cl NQR spectrum. It is shown that the most likely pathway for phosphorus-carbon chlorotropic rearrangement for both phosphazopentachloroethane and its solvate with two molecules of chloroform is the sigmatropic route. Institute of Bioorganic and Oil Chemistry, National Academy of Sciences of Ukraine, 1 Murmanskaya ul., Kiev 02094, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 36, No. 3, pp. 177–181, May–June, 2000.     

A calorimetric adsorption study on the interaction of water with hydroxylated surface of γ-Al2O3

The curve for the differential heat of adsorption of water on γ aluminum oxide has parts related to the interaction of the adsorbed water molecules with surface molecules of coordinated water and with acid and basic hydroxyl groups. Estimates have been made of the effective charges and hydration numbers for three of these adsorption centers. Textural changes have been observed in the γ-Al₂O₃ particles related to interplate swelling in the secondary sorbent packets into which the primary particles are linked. A. V. Dumanskii Institute for Colloid and Water Chemistry, National Academy of Sciences of Ukraine, 42 Prospekt Akademika Vernadskogo, Kiev-142 03680, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 36, No. 2, pp. 121–125, March–April, 2000.     

Structure-reactivity cross correlations in nucleophilic substitution: Isoparametricity and transition-state structure

Data are surveyed on cross correlations for nucleophilic substitution at benzoyl, benzyl, and benzhydryl carbon atoms. The cross correlation coefficients and isoparametric points are used to interpret the reaction mechanisms. Donetsk State University, 24 Universitetskaya ul., Donetsk 340055, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 35, No. 2, pp. 67–78, March–April, 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.     

A total of three years of the publication of the journal <Emphasis Type="Italic">Metody i Ob”ekty Khimicheskogo Analiza</Emphasis>

The contents of the journal Metody i Ob”ekty Khimicheskogo Analiza for 2006–2008 are analyzed. Specific features of the new journal are revealed that reflect the features of the development of analytical chemistry in Ukraine.     

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.     

Study of the acidity of zeolite alkylation catalysts by temperature programmed ammonia desorption

The temperature programmed desorption (TPD) spectrum of ammonia from HLaCaNaY alkylation catalysts shows a strong band with maximum at 389°C, which virtually coincides with the optimal sample activation temperature (380°C). The TPD spectrum was found to account for the specific features of the acidity of these alkylation catalysts. Institute of Bioorganic and Petroleum Chemistry, National Academy of Sciences of Ukraine, 1 Murmanskaya ul., Kiev 02094, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 36, No. 4, pp. 247–250, July–August, 2000.     

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.     

Electronic structure of Al-Cu-Fe quasicrystals

The electronic structure of the Al-Cu-Fe quasicrystal is calculated by the TB-LMTO-ASA method in reciprocal space. The atomic structure of the quasicrystal is modeled by three approximants with 8, 16, and 40 atoms per unit cell. The following characteristics are calculated: partial densities of states for all components of the alloy, total density of states, and charge redistribution between the alloy components. The calculated densities of states are compared with the experimental data obtained by X-ray photoelectron spectroscopy. Good agreement between the experimental spectrum and the theoretical density of states curve is observed for the approximant with 40 atoms per unit cell. In other cases, the agreement is much worse. The calculated data are used to interpret the fundamental features of the experimental spectrum. The results of calculations show that the charge is transferred from transition metal to aluminum atoms, giving rise to d states of aluminum in the occupied part of the band. Translated fromZhurnal Strukturnoi Khimii, Vol. 41, No. 3, pp. 525-531, May–June, 2000.     

Effect of silica on the stability of the nanostructure and texture of fine-particle alumina

The effect of the modification of aluminum oxide with silicon oxide on the stability of fine-particle Γ- and δ-Al₂O₃ phases upon heat treatment in the wide temperature range of 550–1500°C was studied. It was found that the Γ- and δ-Al₂O₃ phases modified with silica are thermally stable up to higher temperatures than pure aluminum oxide. This is due to changes in the real structure of the modified samples, specifically, an increase in the concentration of extensive defects stabilized by hydroxyl groups bound to not only aluminum atoms but also silicon atoms. It is likely that Si-OH groups, which are thermally more stable than Al-OH groups, stabilize the microstructure of Γ- and δ-Al₂O₃ to higher temperatures, as compared with aluminum oxide containing no additives. Simultaneously, an increase in the thermal stability of the modified samples is accompanied by the retention of a high specific surface area and a developed pore structure at higher treatment temperatures.     

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.     

Correlation between structure and catalytic activity of manganese oxides in liquid-phase oxidation of 1-octene

We have studied the correlation between the crystal structure and the catalytic activity of manganese oxides MnO, MnO₂, Mn₃O₄, and Mn₂O₃ in liquid-phase oxidation of 1-octene by molecular oxygen. The catalytic activity decreases in the series of oxides with octahedral coordination environment for the manganese atoms MnO−Mn₂O₃−MnO₂. The oxide Mn₃O₄ (with mixed tetrahedral and octahedral environment for the Mn atoms) catalyzes the process according to a different mechanism. L'vov Polytechnic State University, 12 S. Bandery ul., L'vov-13 290646, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 34, No. 5, pp. 324–327, September–October, 1998.     

Quantity of sorbed ions and forms of their binding to carbon surface as factors influencing catalytic activity in esterification and hydrolysis reactions

Results are summarized and correlated from studies of how the quantity and nature of sorbed ions and the forms of their binding with the surface of carbon materials (CM) differing in structure and origin will influence the catalytic activity in acid-type reactions. It has been shown that of all of the methods of incorporating metals into the CM surface, the most effective is the ion-exchange modification. It is suggested that the mechanisms of catalysis of protolytic reactions by various ion-exchanged forms of CM are all quite similar. “Sonar” Scientific and Engineering-Technological Center of Biotechnical Systems, National Academy of Sciences of Ukraine, 52/2 Victory Prospect, Kiev 252057, Ukraine. Affiliation of second author: Institute of Sorption and Problems in Endoecology, National Academy of Sciences of Ukraine, 32/34 Academician Palladin Prospect, Kiev-142 252680, Ukraine. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 33, No. 3, pp. 175–179, May–June, 1997.     

Structural and electronic properties of aln and bn wide-gap semiconductors and their B<Subscript>x</Subscript>Al<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>N solid solutions

The structural and electronic properties of B_xAl_1−x N solid solutions (x = 0.25, 0.5, 0.75) were examined by calculating the electronic energy structure by the local coherent potential method within the framework of multiple scattering theory. The charge is transferred from aluminum to nitrogen atoms and increases with the content of boron atoms. The concentration dependences of the structural and electronic properties of these solutions are discussed. __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 46, No. 5, pp. 822–829, September–October, 2005.     

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.     

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.