Cationic dyes and their use for the quantitative extraction-photometric determination of higher carboxylic acids

Cationic dyes of various natures have been investigated in order to select a dye that is stable under strongly alkaline conditions and applicable for the quantitative extraction-photometric determination of higher carboxylic acids. The nature of the dye, solvent, the length of the hydrocarbon radical of carboxylic acids and the pH of the aqueous phase for the extraction of ionic associates of higher carboxylic acids with cationic dye with pyronin G were experimentally studied. The study substantiates the practical application of the cationic dye pyronin G as an effective reagent for the quantitative extraction-photometric determination of higher carboxylic acids.

INFLUENCE OF THE MODIFICATION TYPE OF CHITOSAN WITH CARBONYL-CONTAINING COMPOUNDS ON THE PROPERTIES OF FORMED FILM MATERIALS

The features of the modification of acid-soluble chitosan by carbonyl-containing compounds in solution and by the method of surface modification of molded materials are investigated. The dependence of the rheological properties of polysaccharide solutions on the structure of the hydrocarbon radical of the modifier is established. The formed films based on iminochitosans, obtained by the interaction of the polymer with aldehydes in a solution of acetic acid, have lower surface, hydrophobic, and strength characteristics compared to chitosan films. The possibility of biodegradation of the obtained materials, as well as the dependence of the mass loss of the samples on the HLB level, which can be used to create wound dressings with programmed degradation, is shown.

FLUORESCENCE CHARACTERISTICS OF RHODAMINE 6G AND RHODAMINE C IN WATER-MICELLAR SURFACTANT ENVIRONMENTS

The influence of cationic, anionic, nonionic surfactants and their mixtures on the fluorescence characteristics of rhodamine 6G and Rho-damine C solutions has been investigated. The fluorescence intensity of aqueous solutions of rhodamine 6G and in the presence of cetylpyridinium chloride and sodium dodecyl sulfate has almost unchanged throughout the pH range. The fluorescence intensity of aqueous and water-micellar rhodamine C solutions has been increased in the pH 1-4 range; the signal has been remained unchanged at high pH values. The studies have been carried out at pH 4 for rhodamine 6G and at pH 10 for rhodamine C. The fluorescence characteristics of water-micellar dye - surfactant - non-ionic surfactant systems have been performed at a concentration of Triton X-100 of 3.4·10‑2 mol/l. The interaction with cationic surfactants has shown differences character between the I=f(n) dependences for aqueous solutions of highly hydrophobic rhodamine 6G and more hydrophilic rhodamine C. The study of the effect of the hydrocarbon radical length on the intensity of the fluorescence of rhodamine 6G and rhodamine C has been carried out at two concentrations of cationic surfactants: under the condition of the formation of stoichiometric associates dye with cationic surfactant and in the region of the micellar concentrations of cationic surfactants. The character of the influence of the length of the hydrocarbon radical cationic surfactants on the fluorescence intensity of the dyes can be explained by the increasing role of hydrophobic interactions and the enhancement of solubilization in systems involving long-chain surfactants. The difference in the nature of the associates of rhodamine 6G and rhodamine C with hydrophobic and moderately hydrophobic cationic surfactants has been counterbalanced in the presence of Triton X-100. Reduction of fluorescence intensity of rhodamine 6G in domicile solutions of anionic sodium dodecyl sulfate has been established. The method of fluorescence detection of sodium dodecyl sulfate in reaction with rhodamine 6G has been proposed. The method has been tested in determining of anionic surfactants in the waters after washing clothes.

MODIFICATION OF OLIGOESTER MALEINATE BY ALKYL ESTER OF N-MALEINIMIDOBENZOIC ACID

When using products from unsaturated polyester resins (NPS), often increased requirements for thermal and chemical resistance are raised. Increasing the thermal stability of the PS is possible due to the modification of resins by polymerization compounds, which can copolymerize with both oligoether maleinate and styrene. One of such effective additives is N-phenylmaleinimides. The paper presents the results of modification of unsaturated polyester grade PN-1 UT with alkyl ethers n-maleinimidobenzoic acid. The properties of terpolymers are investigated. The effect of substituents of the aromatic group with N-phenylmaleinimides on the properties of terpolymers was investigated. It is also of interest to study the effect of substituents of the aromatic group in N-phenylmaleinimide on the properties of modified polymers. It is shown that terpolymers due to their maleinimides are superior in strength and thermomechanical properties of the copolymers of oligoestermaleinate and styrene. The increase in the size of the hydrocarbon radical substituents of the aromatic group of maleinimides contributes to the increase of the thermo-and physico-mechanical properties of terpolymers. It is also shown that the glass transition temperature of polymers depends on the content of maleinimides, as well as on the structure of the aromatic group. With an increase in the content of maleinimides (up to 5 wt. %) there is an increase in the glass transition temperature and the beginning of the destructive flow. The greatest increase in glass transition temperature (30 °C) is observed at a content of 3 wt. % butyl ether of n-maleimidobenzoic acid. The increase in the length of the hydrocarbon radical (С5Н11 and С8Н17) of the ester group of n-maleimidobenzoic acid leads to the appearance of a plasticizing effect. Synthesized terpolymers can be recommended as binders in the production of heat-resistant composite materials, in particular, fiberglass.

On the Study of Sorption in the Chiral Separation of the Enantiomers of Salbutamol and Salmeterol by Supercritical Fluid Chromatography

The studied conditions of supercritical fluid chiral chromatography of salbutamol and salbutamol sulfate allowed to assumethe possibility of ionic interactions in the process of separation of enantiomers. It is shown that the structure of the hydrocarbon radical of 1- (4-hydroxy-3- (hydroxymethyl) phenyl) -2-aminoethanol associated with the chiral fragment, and, consequently, the physicochemical characteristics of the substance molecule, such as the number of hydrogen donors and acceptors polar surface, significantly affect the ability to communicate with the sorbent selectors under conditions of supercritical fluid chromatography

CHOICE OF MOLECULE STRUCTURE AND COMPOSITION BASED ON WORKING MECHANIZM OF PHYSICALLY SORBED COLLECTROR’S FORM

In the paper choice method of collector’s molecule structure and composition is shown based on dependence of collecting activity of floatation reagent on power of surface flow of its physically sorbed forms. The method allows to discover influence of structure and composition specialties hydrocarbon fragment and molecule of floatation reagent-collector on extraction of useful component and quality of concentrate. Particular methods of conscious choice of structure and composition of hydrocarbon fragment of collector’s molecule in the context of some known collectors such as N-acidified amino acids, oxo acids and floatation regulators of non-sulphide ores – oxiethylized aliphatic alcohols. The influence of some structural specialties hydrocarbon radical on collecting activity of the reagent is established. These specialties are distance between carboxyl and amido groups in N-acidified amino acids, quantity of oxiethil groups and its location of in hydrocarbon fragment of alcohol or oxo acids.