Thioboronation of acetonitrile

Conclusions The esters of dialkylthioboronic acids add to acetonitrile with the formation of crystalline adducts, which when heated decompose to the starting materials.     

Tetrazoles: L. Microwave-activated alkylation of 5-aryltetrazoles and 1-substituted tetrazole-5-thiones with 1,3-dibromo-2,2-bis(bromomethyl)propane

Alkylation of 5-aryltetrazoles and 1-substituted tetrazole-5-thiones with 1,3-dibromo-2,2-bis(bromomethyl)propane in dimethylformamide in the presence of sodium hydroxide leads to the formation of tetrakis(5-aryltetrazol-2-ylmethyl)methanes and tetrakis(1-R-tetrazol-5-ylsulfanylmethyl)methanes, respectively. Microwave activation considerably shortens the reaction time and increases the yield.     

Derivatives of <Emphasis Type="Italic">ortho</Emphasis>- and <Emphasis Type="Italic">para</Emphasis>-Naphthoquinones and Monoethanolamine Vinyl Ether in Radical Copolymerization with Acrylic Acid

Radical copolymerization of new redox monomers based on derivatives of monoethanolamine vinyl ether and naphthoquinones with acrylic acid was studied.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 1, 2005, pp. 151–154.Original Russian Text Copyright © 2005 by Ergozhin, Mukhitdinova, Shoinbekova, Nikitina, Nuranbaeva, Zhunusova.     

The essence of the new approach to the equation of the monolayer state

A new approach to the theory of the equation of state of the adsorption monolayer is elucidated. The approach is based on the excluded surface area. Expressions for the chemical potential are analyzed and the derivation of a master equation, which can be used to obtain equations of state in different approximations, is demonstrated. The constructed hierarchy of approximations includes both the known equations of state (Planck, van der Waals, van Laar, Frumkin) and new, more accurate equations. The new approach consists in the consideration of the three-dimensional aspect related with the orientation of anisometric particles of a monolayer. The influence of the orientational effect on the equation of the monolayer state and phase transitions is discussed.     

Effect of Solvation on the Decomposition Rate of Azodiisobutyronitrile

The log rate constants of monomolecular decomposition of azodiisobutyronitrile can be quantitatively correlated with solvent properties by means of linear multiparameter equations including various solvation effects; the key factors are the ability of solvents for electrophilic solvation, which favors decomposition, and cohesive energy density, which unfavors the reaction.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 2, 2005, pp. 196–200.Original Russian Text Copyright © 2005 by Makitra, Polyuzhin, Golovata.     

On-line filtration system for determining total chromium and chromium in the soluble fraction of industrial effluents by flow injection flame atomic absorption spectrometry

Two manifolds were assessed for the purpose of determining both the total chromium content and that present as a soluble form in industrial effluents by flow injection flame atomic absorption spectrometry (FI-FAAS). To determine the chromium content in the soluble fraction the samples were used without additional treatment, a 0.45 microm filter being included in the FI system. To determine the total chromium content, the samples were acidified with nitric acid 20% (v/v) and heated for 30 s in a microwave oven (temperatures of about 70 degrees C were reached). The problem posed by the very different concentration range in which total and soluble chromium are present was overcome by using programmed flow rate methodology and by only partially emptying the sample loop. A personal computer controlled both the rotation speed of a peristaltic pump and the volume of sample injected into the system, thus obtaining the dispersion degree required. Using the manifold proposed, the chromium content in the soluble fraction can be determined in the 0.5-20 microg mL(-1) range using a 10 microg mL(-1) single standard for calibration. To determine the total chromium content, a calibration line in the 20-200 microg mL(-1) range was obtained using a single 50 microg mL(-1) chromium standard solution. The reliability of the semi-automatic devices was verified by comparing the results obtained with those found by treating the samples and using both FAAS in a conventional way and a spectrophotometric method using diphenylcarbazide at the 95% confidence level (ANOVA test). The proposed procedures showed a RSD lower than +/-3%.     

Contact Interactions between Individual Fibers of Cellulose and Its Derivatives: Mechanism of Cationic Surfactant Action

The effect of cationic surfactants (cetyltrimethylammonium bromide and tetrabutylammonium iodide) and cationic polyelectrolyte polyethylenimine on the coefficient of friction and adhesion force p(during shear and tensile testing, respectively) at the point contacts between the individual fibers of cellulose, viscose, and cellulose acetate was studied. The comparison of these data with the results of -potential and adsorption measurements enabled us to relate the nonmonotonic dependence of parameters and pon the surfactant concentration to the changes in electrosurface properties and the hydrophilicity or hydrophobicity of the fibers. The specific free energy of interaction U[mJ/m²] was estimated for cellulose acetate fibers.     

Formation of o-nitrosoalkylaminobenzenes in the reaction of benzofurazan s with alcohols in acidic conditions

Summary In the reaction of benzofurazan with isopropanol cyclohexanol o-nitrosoaalkylaminobenzenes are formed besides 2,2-dialkyl-2H-benzimidazole-oxides. In the instance of 4-aminobenzofurazan only 2-nitroso-3-aklaminoanilines are obtained. 5-Nitrobenzofurazan reacts with isopropranol in sulfuric acid to form 4-nitro-2-nitrosoisopropylaminobenzene; however, in the instance of 4-nitrobenzofurazan derivatives the formation of o-nitrosoalkylaminobenzenes has not been observed.Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp, 395–402, March, 1995.Original article submitted January 5, 1995.     

Centennial of the Röntgen's paper on the structure of water

Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Siberian Branch, Novosibirsk, Russia. Translated from Zhurnal Strukturnoi Khimii, Vol. 33, No. 6, pp. 5–7, November–December, 1992.