Chemistry Journal of Moldova

DOI: dx.doi.org/10.19261/cjm.2010.05(1).05

Graphical Abstract: A potentiometric selective sensor based on trinuclear chromium(III) complex as a novel ionophore for the thiocyanateselective electrode is reported. The sensor displays a near Nernstian slope of 57 ± 2 mV per decade, over a wide pH range 3 - 11. The working concentration range of the electrode is 1.10^-5 – 1.10^-1 mol/l with a detection limit of 5.10^-6 mol/l. The sensor has a response time of 20 s and can be used for at least 6 months without any considerable fluctuation of the potential. The selectivity coefficients determined at using the fixed interference method indicate a good discriminating ability towards other anions. The prepared sensor was applied as an indicator electrode in the titration of thiocyanate with Ag⁺.


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DOI: dx.doi.org/10.19261/cjm.2011.06(2).09

Graphical Abstract: The paper studies the corrosive activity of the monatomic alcohol (ethanol, butanol) - gasoline mixtures on the materials from which the internal combustion engines are made. The corrosive influence of these blends was determined in dependence of their composition. It was established that the addition of butanol and triethylamine in the ethanol-gasoline mixture essentially reduces the corrosive activity of this mixture.


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DOI: dx.doi.org/10.19261/cjm.2011.06(2).10

Graphical Abstract: The content of copper and zinc in mineral waters were determined by atomic spectroscopy with preliminary extraction of metals. Validation of the technique was carried out by the method of standard additions and proved the reliability of analytical data.


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DOI: dx.doi.org/10.19261/cjm.2011.06(2).11

Graphical Abstract: The influence of added alcohols, ethanol and butanol, on the main biofuel properties, such as the specific gravity, Reid saturated vapour pressure and distillation curves have been investigated. These properties are intimately related to the fuel composition and their prediction relies on the knowledge of its components characteristics. This research proves the possibility of obtaining fuels with different levels of resistance to detonation, using gasoline with different chemical components and various fractions of alcohols.


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DOI: dx.doi.org/10.19261/cjm.2011.06(1).08

Graphical Abstract: The article investigates phase stability for the mixtures of monoatomic alcohols (ethanol, butanol) with gasoline in the presence of water. There have been determined the optimal storage conditions of mixtures depending on their composition and mixing conditions. The positive influence of butanol on the phase stability of ethanol-gasoline mixtures was detected.


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DOI: dx.doi.org/10.19261/cjm.2011.06(1).09

Graphical Abstract: This paper presents the results of scientific research related to the electrochemical behavior of the complex preparation Enoxil. It was established that the oxidation-reduction process of Enoxil is quasireversible. The reactivity of Enoxil obtained from alcohol soluble enotannins is more pronounced, compared to that obtained from standard enotannins. The dependence of cathodic current intensity on Enoxil concentration is linear. This can be used to establish Enoxil concentration in solution. Cyclic voltamograms were used to establish reduction and oxidation potential and the formal redox potential on platinum electrode in sodium perchlorate aqueous environment. These features can be used for identification and determination of Enoxil in pharmaceuticals.


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DOI: dx.doi.org/10.19261/cjm.2011.06(1).10

Graphical Abstract: The article investigates phase stability of ethanol-gasoline mixtures depending on their composition, water concentration in ethanol and ethanol-gasoline mixture and temperature. There have been determined the perfect functioning conditions of spark ignition engines fueled with ethanol-gasoline mixtures.


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DOI: dx.doi.org/10.19261/cjm.2011.06(1).11

Graphical Abstract: An approach has been developed to determine the equilibrium model in heterogeneous aqueous systems containing a mixture of solid phases from the initial composition of the heterogeneous mixture and the equilibrium values of the pH. This approach allows to significantly reduce the quantity of measured data, properly for solubility measurements. By using the new deduced equations it is possible to determine the solubility products of precipitates on the basis of the known composition of initial mixtures and pH values of saturated solutions avoiding some difficult experimental solubility measurements. The derived relations are useful for solving both direct and indirect equilibrium problems.


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Downloads: 18