A. V. Ul’yanov

Investigation of the reaction products of unsymmetrical dimethylhydrazine with potassium permanganate by gas chromatography-mass spectrometry

The gas chromatography-mass spectrometry technique was used to investigate the composition of the reaction products of unsymmetrical dimethylhydrazine with a potassium permanganate and potassium permanganate-hydrogen peroxide mixture. If the water contamination level is within 50 threshold limit values (TLV) (1 mg/ml), the proposed detoxication method utilizing potassium permanganate in combination with hydrogen peroxide allows for the reduction of the UDMH concentration to a safe level without the accumulation of transformation products. The detoxication of aqueous solutions with significant UDMH concentrations (up to 50000 TLV) (1 g/l) with potassium permanganate alone or in combination with hydrogen peroxide reduces the UDMH concentration to a safe level, but UDMH transformation products, including the extremely toxic nitrozodimethylamine, are accumulated in the solution.

The influence of an intramolecular H-bond on the adsorption of sulfur-containing amino acids on graphitized thermal carbon black

The thermodynamic characteristics of adsorption of sulfur-containing amino acids and their derivatives on the surface of graphitized thermal carbon black were calculated by the molecular statistical method. The parameters of the atom-atom potential function of intermolecular interaction between the S atom in amino acids and the graphite C atom were determined. It was shown that an intramolecular H-bond influenced the adsorption of amino acids on the surface of graphitized thermal carbon black.

Soft ionization mass spectrometry for studying desorption of bioactive compounds from a shungite surface

Ionized products of desorption of biologically active amino compounds (1,1-dimethylhydrazine, diglycine, tyrosine, and tryptophan) from the surface of a modified mineral (shungite-III, Karelia) have been investigated by laser desorption/ionization mass spectrometry methods (MALDI and SALDI). The composition of the ionized products of laser desorption of amino acids from the surface of nanodispersed shungite is almost independent of carbon content in shungite. The comparative analysis of ionized organic compounds desorbed from the surfaces of shungite and carbon black has led to the suggestion that the decomposition and surface transformation of 1,1-dimethylhydrazine molecules mainly occur on the inorganic components of shungite.

On the origin of absorbance band around 1700 cm−1 in FTIR spectra of hypercrosslinked polystyrene

This paper deals with some new arguments corroborating the absence of carbonyl moieties [1] in the chemical structure of hypercrosslinked polystyrenes in spite of the high intensity of the absorption band around 1700 cm−1 in their FTIR spectra. Three additional facts testify to the benefit of this conclusion. First is the appearance of the absorbance band at 1700 cm−1 in a computer-simulated IR spectrum of a rigid highly crosslinked model network that contains no C=O groups. Second, thermal degradation of the hypercrosslinked network with a formal 500% crosslinking density results in emergence in its mass-spectrum of benzene, alkylbenzenes and hydrogen chloride, only. Third, testing the above hypercrosslinked polystyrene as a stationary phase in a GC column shows the polymer to retain aliphatic hydrocarbons, alcohols and ketones largely by dispersion interactions, thus revealing no polar oxygen-containing groups on its surface.

Physicochemical Grounds for Application of Schungite for Neutralization of 1,1-Dimethylhydrazine in Wastewater

Chromatography–mass spectrometry and MALDI mass spectrometry have been used to study the interaction of 1,1-dimethylhydrazine and products of its oxidation with the surface of mineral schungite in aqueous solutions. A comparative analysis has been performed for organic compounds contained in initial and equilibrium 1,1-dimethylhydrazine solutions brought in contact with schungite, as well as compounds desorbed from the modified surfaces of the mineral and its inorganic components. The analysis has revealed the efficiency of schungite as a low-cost and environmentally friendly sorbent capable of catalyzing the profound oxidation of 1,1-dimethylhydrazine and products of its transformation to nontoxic low-molecularmass substances. Environmentally safe methods have been proposed for the regeneration of used schungite.

Chromatographic component of identification of the transformation products of 1,1-dimethylhydrazine in the presence of sulfur

The gas-chromatographic retention indices of the products of 1,1-dimethylhydrazine transformations in the presence of sulfur allows one to confirm and, in ceratin cases, make more exact the results of their gas chromatography-mass spectrometry identification. Features of identification of new compounds, including 1,1-dimethyl-2-thioxohydrazine are discussed.

Influence of the structures of hydrogen-bonded dimeric molecules on their adsorption at graphitized thermal carbon

This study is devoted to the influence of the structures of hydrogen-bonded dimeric molecules on their adsorption at graphitized thermal carbon (GTC). The thermodynamic adsorption characteristics (TACs) of amino acid dimers and dimers of amino acids with acetic acid and formamide at GTC were determined. The results obtained for the adsorption of dimeric molecules at the carbon sorbent were compared with the calculated data for the molecules of the corresponding amino acids at GTC. The geometric parameters of dimeric molecules were varied to analyze the influence of the hydrogen bond lengths on the TACs of the compounds under study.

Molecular statistical calculations of the adsorption of proline and its hydroxy derivatives on graphitized thermal carbon black

The thermodynamic characteristics of adsorption of proline and its hydroxy derivatives on the surface of graphitized thermal carbon black (GTCB) were calculated. The arrangement of hydroxyl groups in the amino acid molecule was shown to influence their adsorption on GTCB. The influence of internal rotation angles in proline and its hydroxy derivative molecules on their adsorption on GTCB was studied.

Comparative analysis of the adsorption of the stereoisomers of hydroxy- and dihydroxyproline at graphitized thermal soot

The thermodynamic characteristics of the adsorption of proline and its derivatives at graphitized thermal soot (GTS) were determined. It was found that the arrangement of the hydroxy groups in the amino acid molecule influences its adsorption at GTS. The thermodynamic characteristics of the adsorption of the stereoisomers of hydroxy- and dihydroxyproline at GTS were calculated. The influence of the internal rotation angles in the molecules of proline and its derivatives on their adsorption at GTS was studied.

Molecular statistics calculations of thermodynamic characteristics of the adsorption of isomeric amino acids on graphitized thermal black

Thermodynamic characteristics of the adsorption of several isomeric amino acids on graphitized thermal black (GTB) are calculated by a molecular statistics method. Parameters of the potential function of the intermolecular pair interaction between an O atom of amino acid and a C atom of graphite are calculated.