R. K. Chernova

Correlations between the Basicity and Proton Affinity of Substituted Anilines

The enthalpies and free energies of gas-phase proton affinity (PA) of aniline and 62 derivatives with different electron donor and electron acceptor substituents in the aromatic ring and at the nitrogen atom were calculated by the PM3 technique. Linear correlations between the shapes of pKa and PA have been found. The deviation of data from the above dependences for ortho-substituted anilines are discussed in the light of possible hydrophobic hydration of molecular fragments near the protonation reaction center.

The Kinetic Aspects of the Interaction of Nitrite Ions with Sulfanilic Acid and 1-Naphthylamine in Aqueous and Micellar Media

AbstractThe kinetics of the reaction of nitrite ions with sulfanilic acid and 1-naphthylamine in aqueous and micellar (sodium dodecyl sulfate) media was studied step-by-step. The diazotization of sulfanilic acid with the nitrite ion was found to occur virtually instantaneously. Anionic surfactant micelles did not influence the rate of this reaction. The calculated effective rate constants and activation energies of the azo coupling reaction between synthesized sulfophenyldiazonium and 1-naphthylamine showed that the passage from water into the micellar medium decelerated the reaction. It was found that sodium dodecyl sulfate micelles played the role of a reagent separator.

Ionic and micellar effects in supramolecular self-organizing surfactant media on an example of analytical systems amines-carbonyl compounds

The influence of supramolecular self-organizing surfactant-based media on the condensation reactions of some carbonyl compounds with arylamines (formation of Schiff bases, hydrazones and naphthoquinones) was studied by conductometry, light-scattering spectroscopy, molecular spectroscopy, and tensiometry. The function of surfactants was proved to differ, depending on its concentration: below the critical micelle concentration (CMC) they acted as a reagent, while at higher concentrations, they demonstrated properties of reaction media. The effects observed were analyzed, regarding their potency to govern indicatory reactions in the systems specified, reduce limits of detection for the determination of carbonyl and amino-compounds, refine analytical parameters of the condensation reactions, and broaden the area of their application.

Antibacterial Composites Based on a Natural Sorbent

The paper presents an investigation of the antibacterial activity of composites that are obtained based on a natural sorbent with immobilized antibiotics, tetracycline, and doxycycline. Both the investigated composites effectively inhibited Staphylococcus aureus, but were not effective against Escherichia coli. The paper also presents the results of an investigation of the elemental composition and some characteristics of the porous surface of the glauconite sorbent of the Beloozero field in Saratov oblast.

Determination of the sorption characteristics of glauconite during extraction of a pharmaceutical from an aqueous medium

A technique for preparing enriched glauconite on the basis of a natural mineral from the Beloozyorskoe field of Saratov oblast has been developed. The results of a study of the chemical composition, surface structure, and certain physicochemical properties of the samples of the sorbent are presented. The sorption of ambroxol hydrochloride ions from aqueous solutions has been studied using natural and enriched glauconite. The sorption isotherms, are approximated by the Langmuir equation, have been obtained, and the values of the maximum sorptive capacities have been calculated. Based on the obtained data, conclusions have been drawn on using the studied natural mineral sorbents to extract the above-mentioned substance from aqueous solutions.

Copper nanoparticles obtained by chemical reduction stabilized by micelles of various surfactants

We carried out the synthesis of copper nanoparticles via chemical reduction of micelles stabilized by various surfactants of different nature, such as cetylpyridinium chloride (CPC) and cetyltrimethylammonium bromide (CTAB). We investigated the sustainability of the products of synthesis, i.e. copper nanoparticles stabilized by micelles of various surfactants, after the period of 50 days. Surface morphology and elemental composition of obtained copper nanoparticles were characterized by scanning electron microscopy (SEM).

Synthesis of glauconite composites and study of their antibacterial activity

The elemental composition, the surface morphology and the sorption properties of glauconite from the Beloozerskoye deposit in Saratov Region were investigated. The nanocomposites based on glauconite as a matrix with doxycycline and tetracycline were synthesised. The antibacterial activity of the obtained composites against Staphylococcus aureus was studies.

Effect of the micellar surfactant nanoreactors on the reactions of 2,4-dinitrophenylhydrazine with some aldehydes

By thermogravimetry, the IR and electronic spectroscopy physicochemical characteristics of systems including aromatic aldehydes, 2,4-dinitrophenylhydrazine, and a surfactant were investigated. Selective solubilization effect of the cationic surfactant (cetylpyridinium chloride) micelles on the aci-form of hydrazone arising in the alkaline medium was found. The universal character of solubilization by the cationic surfactant micelles in the aromatic aldehyde—2,4-dinitrophenylhydrazine systems was shown by an example of the benzaldehyde derivatives with substituents of different nature. This effect leads to the increase in solubility of the reaction products and the aggregative stability of solutions.

Micellar catalysis in the systems arylamine-diphenylamine-NO2−

By methods of UV and IR spectroscopy and thermogravimetry reactions of diazotizaion and azo coupling were studied in the systems of primary arylamine (p-nitro-, p-carboxy- and p-sulfoaniline)- diphenylamine -nitrite ion in water and micellar media on the basis of surfactants. The micellar catalysis effect of sodium dodecylsulfate in the micellar media was revealed. Rate of diazotization was shown to be independent of the surfactants of various types. Formation of ionic associates of azo dyes with dodecylsulfate anions in premicellar region was established and physicochemical characteristics of the associates were estimated.