Structure and properties of new dicationic ionic liquid DBTMEDA(BF4)2

Structural Chemistry - Dicationic ionic liquid (IL) dibutyltetramethylethylenediammonium tetrafluoridoborate was synthesized for the first time by quaternization followed by ion exchange. The...     

Etching of polyvinylidene fluoride with an alkaline solution of potassium permanganate

Kinetics of polyvinylidene fluoride etching with a permanganate alkaline solution used in manufacture of track membranes from hydrogen-containing fluoropolymers, and also products formed in the process, were studied in relation to temperature and relative content of mixture components.     

Generation of X-rays at bubble cavitation in a fast liquid jet in dielectric channels

The paper presents the results of studying the combined shock-wave radiation-emission processes associated with cavitation phenomena that occur at fast directional motion of a liquid jet into a closed working chamber through narrow dielectric channels. These processes induce high-power tunable X-ray radiation outside the chamber. At a relatively small liquid pressure, cavitation has been shown to generate shock waves in the chamber walls, which excites surface atoms and leads to the emission of X-rays from the outer surface of the chamber. At a high liquid pressure, the liquid jet does not touch the chamber walls and the cavitational shock waves lead to the excitation of the surface atoms of the jet itself accompanied by the generation of optical and X-ray radiation in the jet, which has been also observed in experiments.     

Radioactive Waste Classification in the Russian Federation and the USA

Physics of Atomic Nuclei - Approaches to the system of radioactive waste classification in the USA and the Russian Federation were considered. The variety of sources of radioactive waste generation...     

Kinetic studies of thiolane synthesis from tetrahydrofurane and H2S

Kinetic studies of tetrahydrofuran reaction with H₂S were carried out in a flow-circulation reactor. Presumably, the reaction takes place through dissociative chemisorption of reactants and the interaction of surface structures formed to produce thiolane and water. A kinetic equation that agrees with the suggested mechanism has been derived.

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Structural and thermoanalytical features of novel morpholinium-based high-voltage ionic liquid

Ionic liquid N-methyl-N-(2-(2-methoxyethoxy)-ethyl)-morpholinium bis-(trifluoromethylsulfonyl) imide was synthesized for the first time by nucleophilic substitution of bromide ion by N-methyl-morpholine. The composition was confirmed by ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy. Using thermal analysis and mass spectroscopy, thermal stability of this ionic liquid as well as possible directions of its destruction was analyzed. Melting point for this liquid using differential scanning calorimetry (DSC) was estimated in the range (?80 to ?74) °C. The dependence of electroconductivity of acetonitrile solution on concentration and temperature was studied for dissociation constant and conductivity activation energy calculations, respectively. The electrochemical stability window for this ionic liquid was defined by cyclic voltammetry and estimated as 4.84 V.     

Generation of intense directional radiation during the fast motion of a liquid jet through a narrow dielectric channel

The results of theoretical and experimental studies of the cavitation phenomena in the volume of a moving liquid jet after its passing through thin and long oriented channels in dielectrics are considered. It is shown that the stationary generation of intense directional radiation in the optical range occurs in the moving jet volume as a threshold pressure is reached in the liquid (pure spindle oil). The parameters of radiation are close to those of laser radiation. The effective temperature of the generation region was estimated as corresponding to 50–100 eV. In some cases, optical radiation is accompanied by the pulsed generation of directional gamma radiation. These processes are accompanied by a sequence of high-voltage electric discharges of a great length in the liquid bulk and at the surface, corresponding to potential differences of 50–100 kV. One of the causes of the observed phenomena can be energetically favorable nuclear fusion reactions involving light nuclei in the liquid jet volume. It was shown that such processes can be efficiently stimulated by multibubble cavitation.     

Mathematical simulation of the compression process of a vapor bubble at a pressure increase in the surrounding liquid

The thermophysical and hydrodynamic processes in a spherical vapor bubble and the surrounding liquid at increasing external pressure are investigated by using a numerical simulation method. The investigation is performed on the basis of a new mathematical model belonging to the class of models of homobaric bubbles (the pressure in the bubble is homogeneous at nonhomogeneous temperature and density). The model takes into account the following main physical effects: the viscosity of the liquid, the heat conductivity of the liquid and vapor, the surface tension, and the phase transitions at the bubble surface. An energy equation taking into account convective heat transfer and viscous dissipation in the liquid is used to calculate the temperature fields in the liquid and vapor. The model also takes into account the dependence of the thermophysical properties on the temperature. A distinctive feature of the proposed model is that the integral conservation law of the system’s total energy (including the kinetic energy of the liquid, the surface energy, and the internal energy of the liquid and vapor) is exactly satisfied (without allowance for the kinetic energy of the vapor). As a result of the numerical simulation of the compression of vapor bubbles in water, we obtained data for the major characteristics of the process at considerable degrees of compression. It is shown that the heat and mass transfer between the vapor in a bubble and the surrounding liquid considerably slow down the temperature increase in the bubble.     

Reaction of tetrahydrofuran with H2S in the presence of Na+/γ-Al2O3

Modification of -Al₂O₃ by sodium hydroxide promotes the increase of surface basicity but does not exert a strong effect on catalytic activity in the reaction of thiolane production from tetrahydrofuran and H₂S. Introduction of NaOH to -Al₂O₃ in small concentration increases the number of Lewis acid centers but decreases their strength. The activity of Na/-Al₂O₃ referred to one Lewis acid center drops.