Publications (20)17.93 Total impact
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Article: Nanosized Pt-, Ru-, and Pd-containing catalysts for organic synthesis and solution of environmental issues
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ABSTRACT: Synthesis of Pt-, Ru-, and Pd-containing nanoparticles in the pores of polymeric matrix of hypercrosslinked polystyrene, their structure and catalytic properties are under consideration. Physicochemical studies have shown that metal nanoparticle formation depends on the properties of the polymeric matrix porous structure, the nature of metal precursors and the synthesis conditions. The study of catalytic properties of metal nanoparticles stabilized in mesoporous matrices showed promising applications of these systems in the reactions of selective oxidation and hydrogenation, which are intermediate stages in the synthesis of precursors of vitamins and medicines. In order to solve environmental problems, nanocatalysts were investigated in the processes of oxidative degradation of phenol and reductive denitrification of nitrates for purification of sewage and natural water. Keywordsnanocatalysts–organic synthesis–ecology–hypercrosslinked polystyrene–Pt–Ru–Pd–oxidative degradation of phenols–catalytic oxidation of glucose–catalytic oxidation of phenolCatalysis in Industry 05/2012; 3(3):260-270. -
Article: Nanostructured metallopolymer catalysts in fine organic synthesis
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ABSTRACT: The article presents results of the synthesis of the nanocatalysts formed in the nanostructured polymeric environment and their properties. These nanocatalysts were analyzed in the reactions of selective hydrogenation and oxidation, which are the basic stages of synthesis of vitamins and aromatic compounds. The amphiphilic block copolymer micelles, ultrathin layers of polyelectrolytes and the nanopores of hypercrosslinked polymers were used as nanostructured polymeric matrices. The formation and properties of both mono- (Pd, Pt) and bimetallic (PdPt, PdAu, PdZn) nanoparticles stabilized by polymers were considered. The efficiency of nanocatalysts in combination with the high stability makes them easy to produce and promising for industrial application.Catalysis in Industry 04/2012; 2(1):11-19. -
Article: Nanosized catalysts in fine organic synthesis as a basis for developing innovative technologies in the pharmaceutical industry
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ABSTRACT: This investigation of the catalytic properties of noble metal nanoparticles stabilized in hypercrosslinked polystyrene (HPS) matrix shows the prospect for their application in regioselective oxidation region- and enantioselective hydrogenation, which represent key stages for the synthesis of the intermediates and final products of pharmaceutical industry. Commercial use of nanosized catalysts allows shortening the synthetic stages, increasing product yields, and improving the environmental safety of the existing industrial processes. In this review, the synthesis, structure and catalytic properties of mono- (Pt, Ru, Pd), bi- (Pt-Pd, Pt-Ru, Pd-Ru), and trimetallic (Pt-Pd-Ru) nanoparticles stabilized in the pores of a polymeric HPS matrix are discussed. Physicochemical investigations have shown that the formation of metal-containing nanoparticles depends on the properties of the porous polymeric structure, the nature of the initial metal precursor, and the synthesis conditions. The use of nanosized catalysts is revealed to be effective in the most important field of fine organic synthesis: preparation of materials for medicine, vitamins, and food additives (e.g., in the food and pharmaceutical industry).Nanotechnologies in Russia 04/2012; 4(9):647-664. -
Article: Nanosized catalysts as a basis for intensifications of technologies
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ABSTRACT: This investigation of the catalytic properties of noble metal nanoparticles stabilized in hyper crosslinked polystyrene (HPS) matrix shows the prospect for their application in selective hydrogenation, selective oxidation and enantioselective hydrogenation, which represent key stages for the synthesis of the intermediates and final products of pharmaceutical industry. Commercial use of nanosized catalysts allows shortening the synthetic stages, increasing product yields, and improving the environmental safety of the existing industrial processes. In this review, the synthesis, structure and catalytic properties of mono (Pt, Ru, Pd), bi (Pt–Pd, Pt–Ru, Pd–Ru), and trimetallic (Pt–Pd–Ru) nanoparticles stabilized in the pores of a polymeric HPS matrix are discussed. Physicochemical investigations have shown that the formation of metalcontaining nanoparticles depends on the properties of the porous polymeric structure, the nature of the initial metal precursor, and the synthesis conditions. The use of nanosized catalysts is revealed to be effective in the most important field of fine organic synthesis: preparation of materials for medicine, vitamins, and food additives (e.g. in food and pharmaceutical industries).Chemical Engineering and Processing: Process Intensification. 01/2011; 50:1041-1053. -
Article: Kinetics of phenol hydrogenation over Pd-containing hypercrosslinked polystyrene
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ABSTRACT: Hypercrosslinked polystyrene (HPS) has been used as a support for preparation of the palladium-based catalyst, Pd/HPS, for gas phase hydrogenation of phenol to cyclohexanone. At the phenol conversion 99%, the catalyst provides selectivity for ketone not lower than 95 mol%. The Pd/HPS catalyst showed high stability, retaining its catalytic performance at least for 20 days. Kinetics was used to compare Pd/HPS with the commercial Pd/Al2O3 catalyst. The catalytic efficiency was assessed using the derived dimensionless kinetic equation without a ‘time’ parameter. Three major reaction routes with their rate parameters and activation energies were revealed. From kinetic parameters, the maximum possible yield of cyclohexanone in the temperature range of 120–180 °C was determined. The important feature of the Pd/HPS catalyst is that selectivity is independent of the temperature at a certain phenol conversion. At elevated temperatures (160–180 °C), the selectivity is at least 2–3% higher as compared to the commercial catalyst Pd/Al2O3, which makes Pd/HPS largely promising for industrial applications.Chemical Engineering Journal. 01/2011; 176–177:33-41. -
Article: Kinetics of phenol oxidation over hypercrosslinked polystyrene impregnated with Pt nanoparticles
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ABSTRACT: Liqiud-phase catalytic wet-air oxidation (CWAO) of phenolic compounds is one of the most prospective methods of waste water purification at high concentrations of toxic phenolic compounds. In this work the synthesis and catalytic properties of mixed platinum-containing nanoparticles stabilized in polymeric matrix of hypercrosslinked polystyrene are discussed. The size of platinum nanoparticles was determined by transmission electron microscopy. Proposed catalytic system showed the high activity, selectivity and stability in the phenol CWAO. The optimal conditions of phenol oxidation leading to the selectivity of 98–99% at 99% conversion were determined and the kinetics of the process at various catalyst loadings, substrate concentrations, and temperatures was studied. Mathematical modelling of the process was carried out allowing the calculation of the reaction network model.Chemical Engineering Journal 01/2007; 134(1-3):256-261. · 3.46 Impact Factor -
Article: Platinum-containing hyper-cross-linked polystyrene as a modifier-free selective catalyst for L-sorbose oxidation.
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ABSTRACT: Impregnation of hyper-cross-linked polystyrene (HPS) with tetrahydrofuran (THF) or methanol (ML) solutions containing platinic acid results in the formation of Pt(II) complexes within the nanocavities of HPS. Subsequent reduction of the complexes by H2 yields stable Pt nanoparticles with a mean diameter of 1.3 nm in THF and 1.4 nm in ML. The highest selectivity (98% at 100% conversion) measured during the catalytic oxidation of L-sorbose in water is obtained with the HPS-Pt-THF complex prior to H2 reduction. During an induction period of about 100 min, L-sorbose conversion is negligible while catalytic species develop in situ. The structure of the catalyst isolated after the induction period is analyzed by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. Electron micrographs reveal a broad distribution of Pt nanoparticles, 71% of which measure less than or equal to 2.0 nm in diameter. These nanoparticles are most likely responsible for the high catalytic activity and selectivity observed. The formation of nanoparticles measuring up to 5.9 nm in diameter is attributed to the facilitated intercavity transport and aggregation of smaller nanoparticles in swollen HPS. The catalytic properties of these novel Pt nanoparticles are highly robust, remaining stable even after 15 repeated uses.Journal of the American Chemical Society 11/2001; 123(43):10502-10. · 9.91 Impact Factor -
Article: Nanostructured Inorganic−Organic Composites as a Basis for Solid Polymer Electrolytes with Enhanced Properties
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ABSTRACT: A family of lithium electrolyte materials based on a polymer−inorganic hybrid is described. The base material is a blend of poly(ethylene oxide) and an organic−inorganic composite made from polyether-functionalized methoxysilanes and aluminum alkoxides. Lithium is incorporated through addition of a salt. The resulting materials are shown through a combination of methods, including transmission electron microscopy and solid-state NMR, to consist of an amorphous inorganic network, with nanoscopic voids, which stabilize the added polymer. The composite polymer electrolytes show good resistance to crystallization and good conductivity, as determined by differential scanning calorimetry and impedance measurements, respectively. The nanoscale structure of the underlying inorganic material is concluded to be responsible for the bulk properties of the system, especially those that differ from the properties of similar, pure salt-in-polymer electrolytes.08/2001; -
Article: Cobalt Nanoparticle Formation in the Pores of Hyper-Cross-Linked Polystyrene: Control of Nanoparticle Growth and Morphology
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ABSTRACT: Impregnation of hyper-cross-linked polystyrene (HPS) by either Co2(CO)8 in 2-propanol or the [Co(DMF)6]2+[Co(CO)4]-2 complex in dimethylformamide (DMF), followed by thermolysis at 200 °C, results in the formation of discrete Co nanoparticles. The concentration and characteristics of such nanoparticles were investigated by X-ray fluorescence (XRF) spectroscopy, ferromagnetic resonance (FMR) spectroscopy, and transmission electron microscopy (TEM). The FMR data here confirm the formation of spherical nanoparticles. At relatively low concentrations of Co, the magnitude of the FMR line width reveals that the mean Co nanoparticle diameter is about 2 nm, which agrees closely with the mean particle diameter discerned by TEM. An increase in Co content higher than 8 wt % is accompanied by an increase in mean particle diameter due to an increase in the population of large Co nanoparticles up to 15 nm across. Regulated nanoparticle growth over a wide range of Co concentrations is attributed to nanoscale HPS cavities, which serve to physically restrict the size of growing particles.10/1999; -
Article: Polystyrene-block-Poly(ethylene oxide) Micelles in Aqueous Solution
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ABSTRACT: The formation of micelles, micellar clusters, and aggregates in aqueous solutions of polystyrene-block-poly(ethylene oxide) macromolecules (PS-b-PEO) in the presence of various additives is studied. Behavior of the PS-b-PEO micellar solutions is examined with static light scattering and sedimentation in the ultracentrifuge. Sedimentograms of the solution of PS-b-PEO in water exhibit two peaks which correspond to the formation of single micelles (Rg = 12.8 nm) and secondary micellar clusters (Rg = 42.1 nm). Experimental data show that the weight fraction of micelles and micellar clusters in the solution strongly depends on the chemical composition of the dispersing media. The addition of 1.5 vol % toluene, which is a good solvent for the glassy polystyrene cores, decomposes the micellar clusters due to an increase of mobility of macromolecules forming micelles. Addition of inorganic salts interacting with poly(ethylene oxide) tails also results in the disappearance of micellar clusters. Alcohols introduced as cosolvents can strongly change the morphology of the amphiphilic PS-b-PEO micelles.08/1999; -
Article: Complexes of Polyelectrolyte Gels with Oppositely Charged Surfactants: Interaction with Metal Ions and Metal Nanoparticle Formation
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ABSTRACT: The interaction of polyelectrolyte gel/oppositely charged surfactant complexes with AgNO3 and H2PtCl6 was investigated. Three kinds of gel/surfactant complexes were studied: a complex of the anionic gel of poly(methacrylic acid) with the cationic surfactant cetylpyridinium chloride and complexes of the cationic gel of poly(diallyldimethylammonium chloride) with two anionic surfactants: sodium dodecyl sulfate and sodium dodecylbenzenesulfonate. After reduction of metal compounds by hydrazine−hydrate, sodium borohydride, or UV-irradiation, Pt and Ag metal particles embedded in the body of the hydrogel were formed. The degree of metal ion exchange was higher for the oppositely charged metal ion and the polyelectrolyte gel; i.e., Ag+ is strongly absorbed by the complex poly(methacrylic acid)/cationic surfactant, while PtCl62- ions are mainly consumed by the complex of poly(diallyldimethylammonium chloride) gel with anionic surfactants. Small-angle X-ray scattering data indicated different structural changes in the gel for the complex of an anionic gel with cationic surfactant and for complexes of cationic gel with anionic surfactants. The incorporation of the metal ions in the body of the hydrogel and the growth of metal nanoparticles was found to lead to the loss of order provided by surfactant aggregates if the distance between charged groups in the polyelectrolyte does not provide a strong hydrophobic interaction between surfactant molecules.01/1998; -
Article: Cobalt nanoparticles in block copolymer micelles: Preparation and properties
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ABSTRACT: The preparation and properties of Co nanoparticles in polystyrene(PS)-poly-4-vinyl-pyridine(PVP) micelles were studied. Elementary Co was generated by two methods : (i) by reduction of micelles loaded with CoCl2, and (ii) by thermal decomposition of Co2(CO)8 in micellar solutions of such block copolymers. Co particles formed by both processes are effectively stabilized by the block copolymer matrix and do not aggregate. For CoCl2 as a Cosource, the formed particles have a size less than 1 nm. Thermal treatment of such dried polymers at 200 °C for 2 h leads to spherical particles of 3–5 nm in size. The polymeric hybrid materials prepared in this way display remarkably high values of magnetization at rather low Co contents in the polymer, i.e., we obtain a tenfold increase of the specific magnetization density. Co2(CO)8 as a Co source, results in a more complex behavior. Co2(CO)8 dissolves in the solvent as well as in the micelle core where it is converted to an cationic—anionic complex involving the 4-VP units. The shape and size of the Co nanoparticles formed by thermolysis can be controlled by the balance of 4-VP/Co and can be varied from spherical particles in the limit of lower Co loads being mainly attached to the micelle core to a star-like and cubic morphology in case of excess of Co2(CO)8. Both superparamagnetic and ferromagnetic materials can be prepared. For ferromagnetic samples coercive force varies from 250 to 475 Oe depending on Co content and polymer sample.Colloid and Polymer Science 04/1997; 275(5):426-431. · 2.33 Impact Factor -
Article: Specific features of complexation of organometallic compounds with polybutadiene and its copolymer in solution
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ABSTRACT: The formation of complexes of Zr, Fe, W, Pd, and Rh with polybutadiene and polystyrene-polybutadiene block copolymers is studied. Linear organometallic polymers are formed when every metal complex interacts either with one active group of the polymer or with two groups forming a stable cyclic or conjugated bonds. Polymer cross-linking occurs when complex formation takes place with two or more active groups that belong to different macromolecules. The interactions with palladium and rhodium compounds are typical examples.Journal of Inorganic and Organometallic Polymers 11/1994; 4(4):415-424. -
Article: Surface characteristics of block copolymer solutions and reaction mixture components as key elements to understanding of the behavior of block copolymer based hydrogenation catalyst
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ABSTRACT: This work is devoted to the investigation of surface characteristics such as contact angle and surface tension of the poly(ethylene oxide)-block-poly(2-vinyl pyridine) (PEO-b-P2VP) block copolymer solutions. The block copolymer was used for the development of micellar and heterogenized selective Pd-containing hydrogenation catalysts. Besides, surface tension of solutions of a reactant (dehydrolinalool) and a product (linalool) were investigated as a function of solvent nature and composition. It was found that varying the solvent polarity allows tuning the access of the reactant to catalytic sites and the removal of the product from the micelle core. The surface tension measurements were in accordance with the results of the catalytic investigation. Among the investigated solvents the iso-propanol plus water mixture (30 vol.% of H2O) was found to provide the best catalytic properties, although such a complex solvent revealed higher surface tension than pure iso-propanol. In the case of heterogenized catalyst, a scheme of the block copolymer interaction with the SiO2 surface was proposed.Colloids and Surfaces A Physicochemical and Engineering Aspects 383:102-108. · 2.24 Impact Factor -
Article: PHYS 458-Characterization and application of self-assembled virus-like particles with magnetic cores
Abstracts of Papers of the American Chemical Society. 235. -
Article: Mixed Co/Fe oxide nanoparticles in block copolymer micelles
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ABSTRACT: Journal articleLangmuir 24(2008),12618-12626. -
Article: Hydrophilic monodisperse magnetic nanoparticles protected by an amphiphilic alternating copolymer
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ABSTRACT: Journal articleJ. Phys. Chem. C 112(2008),16809-16817. -
Article: Composite Solid Polymer Electrolytes Based on Pluronics: Does Ordering Matter?
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ABSTRACT: Journal articleChem. Mater. 19 (25)(2007)6258,6265. -
Article: Interaction of metal compounds with ‘double-hydrophilic’ block copolymers in aqueous medium and metal colloid formation
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ABSTRACT: The interaction of a ‘double-hydrophilic’ polyethyleneoxide-polyethyleneimine block copolymer (PEO-b-PEI) with AuCl3, PdCl2, Na2PdCl4, H2PtCl6·6H2O, Na2PtCl6·6H2O, and K2PtCl4 in aqueous medium was studied. Micellar structure formation was observed for all metal compounds except Na2PdCl4 where additional protonation of the polymer was required to induce micelle formation. The characteristics of the micelles formed depended strongly on the metal type, the molar ratio polymermetal compound, and the type of reducing agent. Micellization in the presence of AuCl3·H2O is accompanied with reduction of the salt and the formation of gold colloid without reducing agent induced by oxidation of the PEI block. The interaction with PtCl62− ions results in narrowly distributed micelles wi size depending on the metal compound loading. In the case of loading with H2PtCl6, it was found that the size and shape of the colloids can be controlled by changing the molar ratio PEI:metal salt. The lower is the metal loading, the smaller are the particles. In addition, differently shaped Pt colloids were observed. This phenomenon can be controlled by the relative ratio of reactants.Inorganica Chimica Acta. -
Article: Morphology of hybrid poly styrene block poly ethylene oxide micelles Analytical ultracentrifugation and SANS studies
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2012
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Russian Academy of Sciences
Moscow, Moscow, Russia
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