Химия

Chitosan (CS) with a viscosity-average molecular weight of 200 kDa and a deacetylation degree of 82 mol%, produced by Bioprogress Ltd. (RF) has been used in this work. Aqueous solutions of enantiomeric salt complexes of CS with L- and D-aspartic acid (AspA) have been obtained at an equimolar CS:AspA ratio, in terms of amino groups. Powders of CS·L-(D-) AspA salts have been isolated from the corresponding solutions by evaporation of water and stored in a desiccator at zero humidity.

2,2-Dimethyl-1,3-dioxane-4,6-dione (Meldrum acid, isopropylidenmalonate) is widely used by synthetic chemists due to its structural features. The dual nature of the reactivity of Meldrum acid (both electrophilic and/or nucleophilic reagent) determines the synthetic value in the construction of new heterocyclic systems with practically signifi cant properties. A wide range of biological activity has been revealed in a number of compounds containing a 2,2-dimethyl-1,3-dioxane-4,6-dione fragment in their structure.

The method has been proposed for the spectrophotometric determination of antibiotics of the cephalosporin (cefuroxime, ceftriaxone, cefotaxime, cefazolin) and penicillin (amoxicillin) groups using chemometric data processing (method of partial least squares, PLS). The absorption spectra of 24 binary mixtures of “cephalosporin – cephalosporin” and 16 binary mixtures of “cephalosporin – amoxicillin” with various concentrations in the range of 3–27 and 5–140 μg/ml have been recorded.

The problem of environmental pollution by human waste products is currently critically relevant. Organic fragments undergo degradation slowly and as a result accumulate in ecosystems. Many studies confi rm the presence of various pollutants in rivers, soils, atmosphere. Despite a large body of work on the search for methods of inactivation and purifi cation of such pollutants, there is no universal method, applicable to various classes of xenobiotics. The purpose of this work has been to study the destructive processes of model systems of xenobiotics of various nature.

Thin-layer chromatography (TLC) has been used to study the infl uence of a number of factors (the nature of the stationary phase, the nature and concentration of the organic solvents and surfactants, the pH of the buff er solution) on the chromatographic characteristics of B vitamins: B1 (thiamine), B6 (pyridoxine), B12 (cyanocobalamin). The stationary phases were plates with polar (Sorbfi l on a polymer (highperformance plates, HTLC) and aluminum substrates), weakly polar (Polyamide-6), and nonpolar (RP-18 on an aluminum substrate) sorbents.

The kinetics and mechanism of vinyl monomer polymerization were studied. Ways to solve some environmental problems of polymer chemistry have been developed, namely, monomer stabilization to avoid the formation of side polymers due to spontaneous polymeriza­ tion while synthesis, purification and storage of monomers, synthesis of environmentally-pure emulgator-free latexes, synthesis of polymer­ ic flocculants for water purification from disperse particles.

We found that the best way to obtain composites and coatings is nanochemical synthesis  using nanopowders. Firstly  we were ob­ tained nanostructure composite and ceramic materials on the surface of aluminum and its alloys (duralumin, avialumin, magnaliya, silumin), consisting of metal matrix (titanium, magnesium and aluminum) and ceramic filler (corundum, periclase, rutile).

Conversion of the propane-butane mixture at presence Pt-containing zeolite catalyst is researched at 300-500°C. It is shown that with increase in temperature of carrying out of process the yield of aromat­ic hydrocarbons, the maximum quality aromatics Ce-Ce increases reaches 40.0%wt at 500°C and a feed space velocity of raw materials 100 lr1. Conversion butanes thus reach is 94.0%.

N-hexane and gasoline fraction conversion on bismuthchromezeolite catalyst at 300-500°C was researched. It was showed that in cataly­ sate total content of izomerization products reduce. The maximum content of aromatic hydrocarbons is 16.5% at 450°C and minimum benzene formation (0.8%). Ennoblement of gasoline fraction on bismuthchromezeolite catalyst contributes increase octane number on 29 points at 400°C. Benzene content is 1.4% that accord with environmental requirements of motor fuels.