OLIGOMERIC GUANIDINE-CONTAINING PROTON CATIONIC IONIC LIQUID

Oligomeric ionic liquids occupy an intermediate position between low molecular weight and polymeric. They are promising as polymer electrolytes in electrochemical devices for various purposes, membranes for the separation of gas mixtures, in sensor technologies, and so on. Oligomeric guanidinium ionic liquids are practically not described in the literature. In terms of studying the effect of the structure of the epoxy component on the properties of oligomeric ionic liquids of this type, it is advisable to introduce into its composition an aliphatic oligoether component. The choice of aliphatic oligoepoxide for the synthesis of guanidinium oligomeric ionic liquids is based on the fact that it is structurally similar to poly - and oligoethylene oxides, which are known to be non-toxic, biodegradable, and reactive oligomeric ionic liquids at elevated temperatures. A new type of reactive oligomeric proton cationic ionic liquid was synthesized by the reaction of oligomeric aliphatic diepoxide with guanidine, followed by neutralization of the product with hydrochloric acid. In this study, the synthesis of proton cationic oligomeric ionic liquids was based on the introduction of guanidinium fragments as end groups of the oligoether aliphatic chain. This reaction is attractive because of the ease of opening the oxirane ring with such a strong nucleophile as guanidine.The reaction forms a fragment with an aliphatic C-N bond, which retains the high basicity of the nitrogen atom. Its structure is characterized by the presence of guanidinium groups at the ends of the aliphatic hydroxyl-containing oligoether chain. The chemical structure of this compound is characterized by IR -, 1H ,13 C NMR spectroscopy methods, and its molecular mass characteristics are determined.The average molecular weight of the synthesized oligomeric ionic liquids is 610 g / mol.The value of the coefficient of polydispersity of the synthesized oligomeric ionic liquids is equal to 1.2. Determination of the content of amino groups in the guanidine-containing oligomer in the basic form by titrometric method allowed to establish that the value found is close to the theoretically calculated value. The synthesized oligomeric proton ionic liquid is characterized by an amorphous structure with two glass transition temperatures. The first lies in the range -70 °C, the second in the region of 70 °C, and the beginning of thermal oxidative destruction is located in the region of 148 °C. The temperature dependence of the ionic conductivity for this compound is nonlinear in the Arrhenius coordinates, which indicates the realization of ionic conductivity mainly due to the free volume in the system. The proton conductivity of this compound is 6.4·10-5–1·10-2Cm/cmin the range of 20–100 °C. The obtained compound exhibits surface-active properties characteristic of classical surfactants, as evidenced by the value of the limiting surface activity – 2.8·102 Nm2 / kmol. The value of CCM is 1.8·10-2 mol/l., and the value of the minimum surface tension – 37.70 mN / m. The synthesized oligomeric ionic liquid is of interest as electrolytes operating under anhydrous conditions, surfactants, disinfectants, and starting reagents for the synthesis of ion-containing blockopolymers.

ЗАСТОСУВАННЯ ІОННО-ПЛАЗМОВИХ МЕТОДІВ ДЛЯ ОТРИМАННЯ ТОНКОПЛІВКОВИХ ПАЛИВНИХ ЕЛЕМЕНТІВ

New demands on aircraft operating systems, along with ever-increasing demands for reduced fuel consumption, pollutant emissions and noise, are driving the search for new cleaner technologies in which fuel cells show great potential. The work demonstrates the achieved level of development of thin-film composite materials using ion-plasma and plasma-chemical methods at JSC FED, which allows creating the prerequisites for changing properties in relation to traditional materials by 2…3 and more orders of magnitude, reducing the operating temperature to 400...600 °C. This makes it possible to develop fundamentally new designs of thin-film fuel cells (10-20 times less thick than the tubular version) and serial technologies for their manufacture in the following directions: application of thin-film compositions to the developed structure, taking into account technological limitations for different deposition methods; obtaining composite materials, which consist of layers: gas-tight electrolyte and electrode layers with thin-film current-collecting contacts; ensuring the separation of gas mixtures with a ceramic electrolyte layer with a thickness of < 50...20 microns; minimizing the thickness of the electrolyte film and other functional layers of the fuel cell; increasing the adhesion strength of layers and corrosion resistance of current-collecting contacts and electrode layers in working environments to ensure the operability of the structure throughout the entire operation process.

Amphiphilic Poly(dimethylsiloxane-ethylene-propylene oxide)-polyisocyanurate Cross-Linked Block Copolymers in a Membrane Gas Separation

Amphiphilic poly(dimethylsiloxane-ethylene-propylene oxide)-polyisocyanurate cross-linked block copolymers based on triblock copolymers of propylene and ethylene oxides with terminal potassium-alcoholate groups (PPEG), octamethylcyclotetrasiloxane (D4) and 2,4-toluene diisocyanate (TDI) were synthesized and investigated. In the first stage of the polymerization process, a multiblock copolymer (MBC) was previously synthesized by polyaddition of D4 to PPEG. The usage of the amphiphilic branched silica derivatives associated with oligomeric medium (ASiP) leads to the structuring of block copolymers via the transetherification reaction of the terminal silanol groups of MBC with ASiP. The molar ratio of PPEG, D4, and TDI, where the polymer chains are packed in the “core-shell” supramolecular structure with microphase separation of the polyoxyethylene, polyoxypropylene and polydimethylsiloxane segments as the shell, was established. Polyisocyanurates build the “core” of the described macromolecular structure. The obtained polymers were studied as membrane materials for the separation of gas mixtures CO2/CH4 and CO2/N2. It was found that obtained polymers are promising as highly selective and productive membrane materials for the separation of gas mixtures containing CO2, CH4 and N2.

Optimization of Cyclic Adsorption Processes and Gas Mixture Separation Plants

The analysis of the cyclic adsorption process and the installation of separation of gas mixtures by the method of pressure swing adsorption as an object of optimization have been carried out. The study found operating (control) variables (the duration of the adsorption stage, the pressure at the compressor outlet, the coefficient of reverse flow for the regeneration of the adsorbent, the program of changes in the opening time of the inlet and outlet valves of the installation); undefined parameters (composition, temperature and pressure of the initial gas-air mixture); output variables of the installation (concentration of oxygen, nitrogen in the product gas flow, the productivity of the installation, the degree of extraction and reduced costs for the production of oxygen with a given purity of 40 - 90 and higher vol.%). A one-stage problem of optimization of the regimes of a stationary periodic process of adsorption separation of atmospheric air and oxygen concentration was formulated and solved by the method of short-cycle adsorption under conditions of partial uncertainty of the initial information in the presence of restrictions on the purity of the product gas, the productivity of the installation and the rate of gas flow in the “frontal layer” of the adsorbent. An iterative algorithm for its solution is proposed.

Modification of Zeolites Y and ZSM-5 adsorption of nanoparticles of transition metals from back-micellar solutions for separation of gas mixtures

On the basis of granular synthetic zeolites NaY, HY, and ZSM-5, adsorbents containing nanoparticles of silver, cobalt, molybdenum, and tungsten were obtained. The samples have a lower surface polarity in comparison with the initial zeolites, which is reflected in the selectivity of a number of samples with respect to argon. This is due to the fact that the argon molecule interacts with zeolites only through nonspecific forces. Modification was performed by interacting with reverse-micellar solutions of nanoparticles. The actual sizes of metal particles and their distribution over the surface of the modified samples of zeolites have been determined by the method of transmission electron microscopy. The samples’ equilibrium adsorption capacities for oxygen and argon (25°С and atmospheric pressure) and the separation coefficient of the argon–oxygen mixture as the ratio of Henry’s coefficients have been determined. It has been demonstrated that samples of the NaY zeolite modified with silver nanoparticles have the separation coefficient value of the argon–oxygen gas mixture equal to 1.6.

Methodology for creating and studying units for adsorption separation and purification of gas mixtures

Methodology for creating and studying technological processes and resource-saving units for adsorption separation and purification of gas mixtures (atmospheric air, synthesis gas) with cyclically changing pressure was developed. A problem-oriented hardware-software complex designed to study the properties and operation regimes of units for adsorption separation of gas mixtures and extraction of product gases was created. The complex can also be used to prepare initial data for the design of industrial units for separation and purification of gas mixtures by the method of pressure swing adsorption. The coefficients of mass transfer and mass conductivity in the adsorbent were calculated for the processes during adsorption and desorption of the adsorptive (nitrogen, oxygen, carbon dioxide and monoxide, hydrogen) using experimentally obtained kinetic curves, and the adequacy of mathematical models was established. Using the hardware-software complex, experimental and numerical studies of technological processes for extraction of product gases (oxygen and hydrogen with a purity of 45 to 95.5 vol.%, from 99 to 99.99 vol.%, respectively), the effect of mass and heat exchange processes and operating variables (“adsorption-desorption” cycle time, pressure at the adsorption step), disturbing influences (composition and temperature of the initial gas mixture) on the performance indicators of the pressure swing adsorption unit were carried out.