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We study the adsorption and inhibitory behavior of derivatives of pyridine on St 3 steel in weak acid media (solutions of H 2 SO 4 with concentrations of 10 mole/m 3 and 500 mole/m 3) . We show that organic compounds with adsorption peaks in the electron spectra at ~'max --" 255-270 nm are specifically adsorbed on the steel. The maximum inhibitory effect is produced by pyridines with electron-acceptor substituents, in particular, 3.5-dibromopyridine. A correlation is established between adsorption and inhibitory properties of molecules with electron-donating substituents. In general, the protective action of pyridines stems from blocking of the metal surface, displacement of the adsorption potential, and the capacity for specific adsorption.Pyridine derivatives are widely used as metal corrosion inhibitors in acid solutions [1]. It is generally accepted that metal corrosion inhibition by applying pyridine derivatives and other amine inhibitors is attributed mainly to the appearance of blocking and energetic effects upon their adsorption [2].The protective action of nitrogen-containing compounds on steels is due to the electron-donor properties of Nalkyd substituents and the blocking effect [3]. With increase of the absolute value of electron density on the nitrogen atom, the pyridine inhibitory ability changes in a V-like manner, and the minimum corresponds to the unsubstituted pyridine [4]. Thus, the protective action of pyridines depends on the re-electron density of the nitrogen atom and on the molar surface of the organic molecule [4].No study of pyridine adsorption on iron and steel has been conducted, and this makes it impossible to estimate the contribution of various effects to the total inhibition of the corrosion process. into the pyridine molecule, its adsorption activity rises to AG~ ~ =-24.0kJ/mole (2-picoline) and AG~ ~ = -23.5 kJ/mole (2,6-1utidine) [7].Adsorption of these compounds from water solutions on powdered Armco iron increases as compared with adsorption on mercury [8], although an inverse dependence would be expected due to the high hydrophilicity of iron. The adsorption of certain pyridines on mercury is claimed [8] to follow from specific intermolecular interactions on the coincidence of characteristic frequencies of optical transitions of organic molecules with maxima of the electron spectrum of a solid surface (the theory of "spectral resonance"). These assumptions on the character of specific adsorption on the solid surface are based on the theory of macroscopic intermolecular interactions [9]. According to this theory, the energy of attraction of a molecule to a semiinfinite body (surface) is described by the following relation where e~ (i~) and e2(i~) are the permittivities of the surface and medium, respectively, on the imaginary axis of

ENERGY CONDENSED PACKAGED SYSTEMS. OXIDIZER COMPONENTS SELECTION Introduction. Ammonium nitrate represents the most large-capacity product of nitric industry, widely used as a fertilizer and as an oxidant at energy condensed systems (ECS), including industrial emulsion explosives (IEE) for the mining industry. The experience of emulsion explosives' use to break rocks shows that these systems are as effective as TNT explosives, but have much efficiency and significantly higher safety level at the same time that their explosion products are more environment-friendly. Literature review. Well known is [1...3] that the IEE do represent highly concentrated inverse emulsions of nitrate salts' water melts in the fuel phase, sensitized with microspheres or gas bubbles. It has been found that most of IEE properties are determined by emulsion dispersion, which increases concurrently to increase of "oxidizer-fuel" boundary surface that provides the system's high sensitivity and detonation characteristics [1...3]. However, dispersion increasing the system failure thermodynamic probability also does increase. ECS emulsion base preparation consists in emulsification of inorganic oxidizing salts' highly concentrated water melts (85...90 %) in fuel phase. However, when IEE application temperatures (10...70 °C), the emulsion dispersed phase represents a supersaturated solution that creates salts crystallization and emulsion breaking conditions, and, consequently, involves the ECS detonation capacity loss. Aim of the Research. To obtain a stable high-dispersion emulsion through well-argued selection of the nature and concentration of the oxidizer phase, fuel phase and emulsifier, as well as the emulsification method. Main Body. The modern emulsion explosives do use as an oxidant the ammonium nitrate (NH 4 NO 3) sodium (NaNO 3) and calcium nitrates (Ca(NO 3) 2). Calculations show that by the excessive oxygen index determined by the so-called oxygen balance (OB) [3], the calcium (OB=48,8 %) and sodium (OB=47 %) nitrates are significantly superior over the ammonium nitrate (OB=20,0 %). Thus, to obtain a balanced redox system used as oxidant for sodium and calcium nitrates we must increase the emulsion content in fuel phase that allows a greater thermal expansion of the ECS explosive effect. However, the total replacement of emulsion's ammonium nitrate with the calcium or sodium nitrates is not effective as under thermal decomposition these nitrates do form solid products that reduces the amount of gases released by IE explosion and respectively blast effect [4]. At the same time, using only ammonium nitrate (AN) as an emulsion systems' oxidant requires maintaining high process temperatures when IEE manufacturing. As ECS component, the water represents a salts' solvent and the base to form a dispersed fluid system that provides producing an IEE convenient for pumping into the well with high throughput. The water content in such emulsion depends on the IEE application and type [1, 2]. For liquid emulsion systems purposed for both open a...

Introduction. Mining enterprises of Ukraine annually consume up to 150 thousand tons of industrial explosives. Until recently industrial explosives were composed of TNT -highly toxic substance that is prohibited in Europe since 1993. Transition of the mining industry on the use of domestic highperformance, safe emulsion explosives (EE) [1] almost completely renounce the use of TNT on open cast mining. At the same time in underground conditions the use of EE is limited due to a number of requirements for such systems.Literature review. It is known [1] that EE are the inverse emulsions of highly concentrated solution of oxidizer (91...93 wt %) in the hydrocarbon medium (7,0...9,0 wt %) sensitized by pore-forming components (gas generating additives). Widespread use of EE in underground mining assumes their production in package form with preservation of stability and high detonation parameters. In [2] it is shown that the best option of oxidant conforming to the specified requirements, has the following composition, wt %: Н 2 О 7,0…10,0; Ca(NO 3 ) 2 27,5…31,5; NH 4 NO 3 58,5…65,59. The composition of specified oxidant has a lower crystallization temperature compared to the monosolution of ammonium nitrate and binary solution "ammonium nitrate -sodium nitrate". This provides a maximum thermal effect of reaction of explosive conversion when interacting with a hydrocarbon medium.Usually [3] oil and products of its processing (oil, diesel fuel, industrial oils, waxes, etc.) are used as fuel phase in energy condensed emulsion systems. At the same time the value of the specific heat of fuel combustion is considered as the main parameter. This value is determined by the relation of carbon and hydrogen content in the molecule (Н/С) and has maximum value for paraffinic hydrocarbons and minimum value for aromatic ones. Besides, the viscosity characteristics of fuel phase are very important for obtaining the emulsion with specified technological parameters.Energy condensed emulsion systems which are used as industrial explosives have mixtures mechanism of detonation, so the chemical reaction proceeds between the oxidant and reductant that are not in molecular contact. According to [4], the high detonation ability of ammonium nitrate explosives can be provided by increasing the contact area of oxidizer and fuel and by the temperature increasing in chemical reaction zone. The width of chemical reaction zone determines the critical detonation diameter [5]. In its turn, the width of chemical reaction zone is determined by the speed of heat release. The speed of heat release depends on the size of oxidant globules in the emulsion, the oxidation rate of fuel phase and the pore size of emulsion, the carrier of which is sensitizer.For the production of energy condensed packaged emulsion systems it is necessary to solve the problem of producing highly viscous emulsion with minimal size of particles of the dispersed phase. Such an emulsion after entering the special materials -sensitizers -provides high detonation parameters and sen...

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