Kinetics and thermochemistry of [2π + 2σ + 2σ]-cycloaddition of quadricyclane to tetracyanoethylene

© 2016, Pleiades Publishing, Ltd.Kinetic data for the unusual [2π + 2σ + 2σ]-cycloaddition of quadricyclane to tetracyanoethylene in toluene have been obtained for the first time. The same reaction in 1,4-dioxane appears to be the most exothermic among known cycloaddition reactions. The entropy of activation and reaction volume differ only slightly from the corresponding parameters of conventional Diels–Alder reactions

Study of Bars and Wires Properties from Al-REM System Alloy

The article presents the results of studies on the production of wire with a diameter of 0,5 mm from aluminum alloy 01417 with a content of rare-earth metals (REM) in the amount of 7–9 % for aircraft construction needs. The deformation modes, the experimental technique and equipment for the implementation of the proposed technology are described.В статье представлены результаты исследований по получению проволоки диаметром 0,5 мм из алюминиевого сплава 01417 с содержанием редкоземельных металлов (РЗМ) в количестве 7–9 % для нужд авиастроения. Описаны режимы деформации, методика проведения экспериментов и оборудование для реализации предложенной технологии.Исследования выполнены при финансовой поддержке РФФИ, Правительства Красноярского края и ООО «Научно-производственный центр Магнитной гидродинамики» в рамках научного проекта № 18-48-242021 «Разработка фундаментальных основ получения деформированных полуфабрикатов электротехнического назначения из высоколегированных сплавов системы Al-РЗМ с применением методов совмещенной обработки и исследование их реологических свойств»

Phase Composition and Microstructure of Crystallization Products of Molten Bi2O3 . GeO2 under Various Cooling Conditions : научное издание

Статья из журнала. Научное издание.-We have studied the influence of melt heat treatment, initial cooling temperature (t(cooling0)), and cooling schedule for a melt containing 50 mol % Bi2O3 and 50 mol % GeO2 on the phase composition, macrostructure, and microstructure of crystallizing sol Abstract—: We have studied the influence of melt heat treatment, initial cooling temperature (tcooling 0), and cooling schedule for a melt containing 50 mol % Bi2O3 and 50 mol % GeO2 on the phase composition, macrostructure, and microstructure of crystallAbstract—: We have studied the influence of melt heat treatment, initial cooling temperature (tcooling 0), and cooling schedule for a melt containing 50 mol % Bi2O3 and 50 mol % GeO2 on the phase composition, macrostructure, and microstructure of crystal

Kinetics and thermochemistry of the [2π+2σ+2σ]-cycloaddition of quadricyclane with 2,3-dicyano-1,4-benzoquinone

© 2019 Wiley Periodicals, Inc. Two-stage [2π+2σ+2σ]-cycloaddition of quadricyclane (2) with 2,3-dicyano-1,4-benzoquinone (1) with a huge difference in the activity of two reaction centers has been studied. In the first stage (kinetic control), the cycloaddition of 2 takes place on the activated С 2 =С 3 bond of 1 to form the monoadduct 3, and in the second stage the cycloaddition of 2 on the С 5 =С 6 bond of the monoadduct 3 occurs by 6 orders of magnitude lower with the formation of bisadduct 4. The structures of adducts 3 and 4 have been proved by NMR data and the X-Ray method, respectively. The kinetics of the first and second stages, the enthalpy of dissolution of 1 in the π-donor solvents, and the enthalpy of the reaction 1+2→3 have been measured

Nanoporosity of Polymer Sorbents and Membrane Materials as Seen by PALS and Low Temperature Gas Sorption

The limits of application of positron annihilation lifetime spectroscopy and low temperature gas sorption for studying nanoporosity of polymer sorbents and membrane materials are discussed relying on the results previously obtained by the authors. For the two methods, limitations are determined by different factors: the dispersion of the material is essential for low temperature gas sorption, while concentration of nanopores of given size is important for positron annihilation lifetime spectroscopy. The both methods came out to be a useful addition to each other in the studies of micropores and mesopores