Kinetics and thermodynamics of the exchange reactions of peroxy radicals with hydroperoxides

The enthalpies and equilibrium constants of the exchange reactions of peroxy radicals with hydroperoxides of various structures are calculated. The experimental data on the reactions of hydrogen atom abstraction by the peroxy radicals from the hydroperoxides are analyzed, and the kinetic parameters characterizing these reactions are calculated using the intersecting parabolas method. The activation energies and rate constants for nine reactions of H atom abstraction by a peroxy radical from the OOH group of a peroxide are calculated using the above parameters. The geometric parameters of the transition states for the reactions are calculated. The low triplet repulsion plays an important role in the fast occurrence of the reactions. The polar interaction in the transition state is manifested in the reactions of the peroxy radicals with hydroperoxides containing a polar group.     

Fullerene-C60, A New Effective Inhibitor of High-Temperature Thermooxidative Degradation of Methyl Methacrylate Copolymers

Fullerene-C₆₀ inhibits thermal and thermooxidative degradation of copolymers of methyl methacrylate with styrene, butyl acrylate, glycidyl methacrylate, and hydroxyethyl methacrylate.     

IR Study of Complexation in the System 1,10-Phenanthroline-LiClO4 (NaClO4)-Acetone

By ab initio calculations, the molecular geometries of 1,10-phenanthroline and its 1 : 1 and 1 : 2 complexes with lithium and sodium ions were optimized, and the frequencies and intensities of normal modes of these species were evaluated. The experimentally observed bands were assigned on the basis of the calculation results. The concentration dependences of the IR spectra of the system 1,10-phenanthroline-LiClO₄ (NaClO₄)-acetone-d ₆ (Cphen 0.05, Csalt from 0 to 1 M) were interpreted. The formation of the 1 : 1 and 1 : 2 complexes was confirmed spectroscopically.     

Synthesis of new multiblock copolymers via cross-metathesis reaction of polytrimethylsilylnorbornene and polycyclooctene

The cross-metathesis reaction between polytrimethylsilylnorbornene and polycyclooctene is investigated for the first time. Using the Grubbs Ru-carbene complex of the first generation, the synthesis of random multiblock copolymers of trimethylsilylnorbornene and cyclooctene is carried out. The effect of the reaction conditions on the block length and thermal and crystalline properties of new copolymers is studied by NMR, GPC, and DSC methods. With the use of in situ ¹Н NMR spectroscopy, the kinetics of the crossmetathesis reaction is investigated. As for unsubstituted polynorbornene (Polym. Sci., Ser. B 58, 292 (2016)), the catalyst interacts initially with polycyclooctene, giving a polymer carbene complex [Ru]=PCO. Further, this complex attacks the polytrimethylsilylnorbornene chain via cross reaction with formation of complex [Ru]=PNB-Si and a diblock copolymer of trimethylsilylnorbornene and cyclooctene as reaction products. The subsequent cross reactions form a multiblock copolymer with gradually increasing block length. Throughout the entire process, the concentration of [Ru]=PCO exceeds the concentration of [Ru]=PNB-Si by more than two orders of magnitude. Simultaneously, the total concentration of carbene complexes decreases in time through their decay. The reaction kinetics is satisfactorily described by a model proposed previously for interaction between polycyclooctene and polynorbornene.     

Phase equilibria and extraction of metal cations in the systems based on synergistic mixtures of potassium bis(alkylpolyoxyethylene)phosphate and alkylbenzyldimethylammonium chloride

The solubility in the system formed by the oxyethylated anionic surfactant potassium bis(alkylpolyoxyethylene)phosphate (oxyphos B), the cationic surfactant alkyldimethylbenz- ylammonium chloride (cathamine AB), and water was studied. The optimal parameters of the extraction process in the systems based on the mixture of surfactants, whose aqueous solutions have the lowest phase-separation temperatures, without a salting-out agent and in the presence of (NH₄)₂SO₄ were established. A possibility of the extraction of metal cations in the oxyphos B—cathamine AB—water system at 50 °С, and the (NH₄)₂SO₄—oxyphos B—cathamine AB—water system at 25 °С was demonstrated. The advantages of application of a mixture of ionic surfactants as compared to the systems based on individual surfactants were revealed.     

Nitrous Oxide: Production,Application, and Protection of the Environment

Russian Journal of General Chemistry - Natural and anthropogenic sources of nitrous oxide were considered, and their contribution to environmental pollution was determined. The effect of N2O on...     

Nanostructures of surfaces of silica films obtained by sol—gel method in the presence of organic additives

The dependence of the antireflection properties of film coatings deposited on the silicate glass obtained by sol—gel method in the presence of organic additives on the dimensions of nanostructures of the silica films was studied.     

Properties of Zinc Oxide Adsorbent for Adsorbing Hydrogen Sulfide

Russian Journal of Applied Chemistry - The paper defines the conditions for the synthesis of hydrogen sulfide adsorbent based on zinc oxide from basic zinc carbonate in order to produce strong,...     

Integrals polynomial in velocity for two-degrees-of-freedom dynamical systems whose configuration space is a torus

We consider dynamical systems with two degrees of freedom whose configuration space is a torus and which admit first integrals polynomial in velocity. We obtain constructive criteria for the existence of conditional linear and quadratic integrals on the two-dimensional torus. Moreover, we show that under some additional conditions the degree of an irreducible integral of the geodesic flow on the torus does not exceed 2.Translated fromMatematicheskie Zametki, Vol. 64, No. 1, pp. 37–44, July, 1998.The author wishes to express his thanks to V. V. Kozlov for his interest and his help in this work.This research was supported by the Russian Foundation for Basic Research under grant No. 96-01-00747.