G. V. Shatalov

New N-vinylamide-based polymers for the preconcetration of nitrophenols from aqueous media

New cross-linked copolymer with molecular imprints of 4-nitrophenol have been synthesized by the radical polymerization of cyclic N-vinyl amides and ethylene glycol dimethacrylate. Sorption characteristics of the obtained polymers depend on the nature of the functional monomer, ratio of components in the prepolymerization mixture, pH of solution, and temperature. It has been established that N-vinylpyrrolidone-based copolymers provide higher selectivity of 4-nitrophenol extraction than N-vinylcaprolactam-based products.

Adsorption preconcentration of 4-nitrophenol from aqueous solutions using polymers based on cyclic N-vinylamides

Crosslinked adsorbents based on N-vinylpyrrolidone and N-vinylcaprolactam are synthesized by free radical copolymerization; their adsorption properties for 4-nitrophenol are studied under batch and dynamic conditions. A method for preconcentrating 4-nitrophenol from dilute aqueous solutions is developed.

Dynamic sorption of nitrophenols from aqueous solutions by polymers based on N-Vinylpyrrolidone

Sorption properties of a polymer based on N-vinylpyrrolidone and ethylene glycol dimethacrylate were studied for the example of sorption of nitrophenols from aqueous solutions under dynamic conditions. The conditions providing a 180–480-fold concentration in dynamic sorption and desorption of nitrophenols from aqueous solution were substantiated.

Regularities in the extraction of B group vitamins with synthetic water-soluble polymers

Common regularities in the extraction of vitamins B1, B2, B6, and B12 from aqueous solutions of polymers (poly-N-vinylpyrrolidone, poly-N-vinylcaprolactam, and polyacrylamide) are studied. The effect of the polymer’s concentration and its structure on the distribution coefficients and the degree of extraction of the vitamins is established. Effective systems for extracting B group vitamins from water-salt solutions are developed as a result of screening stable two-phase systems based on water-soluble polymers.

Copolymers of N-vinylcaprolactam with 1-vinyl- and 1-methacryloyl-3,5-dimethylpyrazole as sorbents of essential α-amino acids in liquid- and solid-phase extraction

Radical copolymerization of N-vinylcaprolactam with 1-vinyl- and 1-methacryloyl-3,5-dimethylpyrazole was performed with the aim of development of effective extraction systems based on nontoxic copolymers for the recovery of essential amino acids histidine, threonine, and tryptophan from aqueous media. Water-soluble and water-insoluble products were obtained. As follows from the copolymerization data, N-vinylcaprolactam exhibits relatively high activity, and the copolymerization constants r1 and r2 for both pairs of comonomers are lower than unity. The influence of the composition and structure of copolymers on the quantitative characteristics (degree of recovery R and distribution coefficient D) of liquid- and solid-phase extraction was studied. The probable mechanism of the interaction of the polymers with α-amino acids was considered. The synthesized copolymers show high performance in recovery of α-amino acids from aqueous media.

Separation of Binary Mixtures of Histidine, Proline, and Methionine in Extraction Systems Based on Water-Soluble Polymers of Vinyl Series

Results of the extraction separation of binary mixtures of histidine, proline, and methionine using water-soluble homo- and copolymers with different molecular weights are presented. The recoveries and separation factors in the systems methionine–proline and histidine–proline are calculated. Amino acids were quantitatively determined by spectrophotometry using their intrinsic absorption in the UV spectral region. The efficiency of amino acid separation was increased using systems additionally containing chloride ions, which facilitate complex formation.

Synthesis of N -vinylformamide and 1-vinyl-(1-methacryloyl)-3,5-dimethylpyrazole copolymers and their extraction ability in relation to histidine in water-salt media

Copolymers of N-vinylformamide (VF) with 1-vinyl-3,5-dimethylpyrazole (VDMP) and 1-methacryloyl-3,5-dimethylpyrazole (MDMP) are synthesized by free radical copolymerization in dioxane. The compositions of copolymers are determined by means of UV-spectroscopy and FTIR, and copolymerization constants r1 and r2 are calculated. N-vinylformamide demonstrates higher reactivity than pyrazole-containing monomers in both cases. Solubility of the synthesized copolymers in water was studied. VF–VDMP copolymers are water soluble at VF content higher than 0.65 molar fractions, and VF–MDMP copolymers—at VF content over 0.8 molar fractions. The formation of complexes between water-soluble copolymers and essential α-amino acid histidine in aqueous solutions is confirmed by UV-spectroscopy, FTIR, dynamic light scattering (DLS), and transition electron microscopy. It is found via DLS that the interactions between the amino acid with copolymer macromolecules lead to conformation changes in macromolecular coils. It is shown that VF–VDMP and VF–MDMP copolymers are effective extragents for histidine. Extraction is carried out at different pH values. The highest extraction degree (98%) is achieved in an acidic medium.

EXTRACTION AND REEXTRACTION OF HISTIDINE AND RIBOFLAVIN BY N-VINYLCAPROLACTAME COPOLYMERS WITH 1-VINYL- AND 1-METHACRYLOYL-3,5-DIMETHYLPYROZOLE

Изв. вузов. Химия и хим. технология. 2016. Т. 59. Вып. 7 55 Для цитирования: Лавлинская М.С., Шаталов Г.В., Мокшина Н.Я., Пахомова О.А., Кузнецов В.А. Экстракция и реэкстракция гистидина и рибофлавина сополимерами n-винилкапролактама с 1-винили 1-метакрилоил-3,5-диметилпиразолом. Изв. вузов. Химия и хим. технология. 2016. Т. 59. Вып. 7. С. 55 60. For citation: Lavlinskaya M.S., Shatalov G.V., Mokshina N.Ya., Pakhomova O.A., Kuznetsov V.A. Extraction and reextraction of histidine and riboflavin by n-vinylcaprolactame copolymers with 1-vinyland 1-methacryloyl-3,5-dimethylpyrozole. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2016. V. 59. N 7. P. 55 60.

Chromatographic determination of nitrophenols in aqueous media after two-stage preconcentration using an N-vinylpyrrolidone-based polymer

Two-stage procedures for the preconcentration of nitrophenols (4-nitrophenol, 2,4- and 2,5-dinitrophenol, and 2,4,6-trinitrophenol) from aqueous solutions are proposed. At the first stage, the preconcentration and desorption of nitrophenols under dynamic conditions is carried out. At the second stage, depending on the nature of the desorption solution, the eluate is evaporated (acetonitrile) or saturated with ammonium sulfate and extracted with acetone (aqueous NH3 solution). The concentration factors are 4000 and 910, respectively. Nitrophenols are determined in concentrates by thin layer chromatography and HPLC, the limits of detection are 1.0–1.8 and 0.25–0.45 μg/L, respectively. The duration of analysis is 200 min.

Sorption of aromatic acids from aqueous solutions by polymer based on N-vinylpyrrolidone

Kinetic and equilibrium characteristics of the sorption of benzoic, salicylic and ortho-chlorobenzoic acids by a new cross-linked sorbent based on N-vinylpyrrolidone were studied at various pH values of the medium. It was found that the molecular sorption of aromatic carboxylic acids from aqueous solutions occurs in the mixed-diffusion mode and the sorption capacity of the polymer grows with increasing acid-base equilibrium constants of the acids. The advisability of introducing a salting-out agent into sorption systems was confirmed. Effective sorption systems and a method for concentration of aromatic carboxylic acids from aqueous solutions by the new cross-linked sorbent based on N-vinylpyrrolidone were suggested.