Complexing polymer sorbents and metal polymer complex catalysts with specially designed structure of active centres

A new approach to a problem of preparation, regulation of properties and formation of three-dimensional structure of complexing polymer sorbents and metal polymer complex catalysts with specially designed structure of active centres has been developed. The main principle is based on the use of “memory” of polymer composition and consists in prearrangement of macromolecules of initial complexing polymer or metal polymer complex catalyst to sorbing metal or hydrocarbon substrate followed by fixation of optimum for particular substrate conformation by intermolecular crosslinking. Using this principle a number of crosslinked complexing polymer sorbents and metal polymer complex catalysts containing phosphorylic, carboxylic, pyridine, amine and imine functional groups have been prepared. It has been shown that prearrangement leads to essential improvement of basic sorption and catalytic properties of the crosslinked complexing polymers - sorption capacity, the rate of uptake, selectivity and catalytic activity.     

Guest-host phenomena in macromolecule-metal complexes

A new principle of design of complexing polymer sorbents and macromolecule-metal complex catalysts with memory to sorbing metals and catalyzing substrates in other words “hosts” able to recognize “guests” was developed. Polyvinylpyridines of different structure, polyethyleneimine and polyethylenepolyamine were selected for preparation of such sorbents and catalysts. Polymer sorbents and catalysts prepared using this principle exhibit guest-host phenomena and demonstrate significantly improved sorption and catalytic properties.     

Physicochemical properties of complexing para-substituted polystyrene sorbents containing functional amino groups

The acid-base properties of the analytical functional groups of complexing polymer sorbents based on aminopolystyrene and the sorption capacity of the sorbents were investigated. The influence of various substituents on the acid-base properties of the sorbents was studied.     

Evaluation of metal fractions in river sediments and waters: application of chelation chromatography-differential pulse anodic stripping voltammetry

The ability of chelation chromatography in combination with differential pulse anodic stripping voltammetry (DPASV) to provide a simple, fast and reliable way of dealing with interionic interferences, competitive complexations, re-adsorption of released metal ions and sorption of spiking metal ions by organic/inorganic materials in the complex matrixes of real natural samples has been critically examined. The technique is based on the selective complexation of target metal fractions on some novel sorbents which are polymeric chelating resins doped on stationary supports (Whatman No. 1 paper and silica gel). The usual complications of leaching of the resin and/or the chelating ligand and colloid retention on the sorption bed at any stage of separation were largely obviated with these sorbents under the operational conditions of metal sorption. A detailed study on the application of such sorbents to the differentiation of ionic (free), labile (ionic plus weakly complexed) and bound (strongly complexed) metal fractions present in local river-sediment and water samples was carried out. Chelating resin-impregnated paper (CRIP) and chelating resin-immobilized silica gel column (CRISC) methods of chromatographic separation of analyte trace metals in combination with the follow-up 'standard addition' procedure of the DPASV technique were employed. A modest attempt has been made to formulate a speciation (fractionation) scheme for metal contents present in river-sediments and waters on the basis of selective retention of ionic and labile fractions on complexing resins.     

Synthesis and catalytic activity of a new class of cyclophosphazenic polypodands

A new class of solid-liquid phase-transfer catalysts (SL-PTC) has been prepared by the reaction of octachlo-rocyclotetraphosphazatetraene and polyethylene glycol monoalkyl ether. These polypodands are found to be powerful metal cation complexing agents and very efficient catalysts in anion promoted reactions (e.g. nucleophilic substitution and reduction reactions).     

Fe/Zn双金属氰化物催化剂催化环氧丙烷聚合的活性结构研究

以氯化锌、铁氰化钾（含有整合剂）的水溶液为原料，合成了铁锌双金属氰化物（DMC）催化剂。为获得高活性的DMC催化剂，需将叔丁醇 、多元醇螯合剂螯合至其结构中，用XRD、XPS等分析手段，对铁锌DMC催化剂的结构与活性进行分析表征。实验发现，DMC催化剂的晶体结构与螯合剂密切相关，螯合剂能显著降低DMC催化剂的结晶程度，从而提高DMC催化剂的活性。同时，氯化锌过量也有利于DMC催化剂活性的提高。并表征了相关DMC催化剂的活性中心。     

超临界二氧化碳渗透技术的研究进展

综述超临界ＣＯ２ 渗透技术的原理、机理以及应用。利用超临界ＣＯ２ 渗透技术可以制备缓释装置、聚合物催化剂、聚合物纳米材料、聚合物金属膜和共混物等     

Soluble metal–polymer catalysts in the hydrogenation of organic compounds

Literature describing the use of soluble metal–polymer catalysts in the molecular hydrogenation of alkenes, alkynes, aromatic and heterocyclic compounds has been reviewed. Special attention has been paid to coordinated metallic and organometallic catalytic systems and highly dispersed colloidal metals stabilized with polymers. The influence of metals, polymers and solvents on the structures of active sites is discussed. The prospects for the application of soluble metal–polymer catalysts in organic synthesis are also considered.     

POLYORGS as complexing sorbents for preconcentration of trace metals

Summary The main characteristics of the complexing sorbents POLYORGS are reviewed. These sorbents contain pyrazole, imidazole, amidoxime, 2-mercaptobenzothiazole, thioglycolanilide and arsenazo groups and exhibit high selectivity in respect to noble, rare-earth and heavy metals. The sorbents POLYORGS are applied for the preconcentration of these metals to be determined in ores, rocks, natural and waste waters, and industrial products. The metal determinations after preconcentration are carried out by means of different instrumental methods (e.g., AAS, XRFA, ICP-AES, NAA) either directly in the sorbent, after elution of the analytes or decomposition of the sorbent.     

Sorption-atomic-absorption determination of gold using VION chemisorption fibers

The sorption of gold(III) from hydrochloric acid solutions on VION chemisorption fibers containing ion-exchange and complexing groups has been studied. Using these sorbents, a combined sorption-atomic-absorption procedure for the determination of gold has been developed. The procedure has been verified in the determination of gold in gold-containing ores.     

Strontium(II) sorption by complexing o-hydroxy-azo-o’-hydroxy functionalized polystyrene polymer sorbents

Optimal parameters for strontium(II) complexing and sorption from aqueous solutions by sorbents based on styrene/divinylbenzene copolymers functionalized with a complexing o-hydroxy-azo-o-hydroxy functionality have been studied, namely, pH_opt, 50% sorption pH (pH₅₀), and the time and temperature of quantitative strontium(II) sorption. Strontium(II) sorption capacities have been determined for the sorbents under study; sorption isotherms have been constructed. For a complex formed with polystyrene-o-hydroxy-azo-o’-hydroxy-sulfobenzene, which is an efficient sorbent, the structure has been determined.     

Zirconium sorption by chelating polymer sorbents with an <Emphasis Type="Italic">o</Emphasis>,<Emphasis Type="Italic">o</Emphasis>′-dihydroxyazo analytical functional group

The complexing properties of new chelating polymer sorbents (CPSs) with an o, o′-dihydroxyazo functionality and zirconium sorption on these sorbents were studied. Quantitative correlations were found between pK′_OH of the analytical functional groups (AFGs) of sorbents and the stability of chelates (logβ) in order to understand the lows governing the effect of the structural features and acid-base properties of the AFGs on zirconium chemisorption parameters. These correlations make it possible to quantitatively predict the physicochemical parameters of sorbents and their chelates, synthesize them, and use CPSs for zirconium preconcentration in analyses of natural and industrial objects.     

双金属氰化物在多组分偶联反应中的催化活性(英文)

Several dual metal cyanide catalysts were prepared from potassium ferrocyanide,metal chloride(where metal = Zn2+,Mn2+,Ni2+,Co2+ and Fe2+),t-butanol(complexing agent) and PEG-4000(co-complexing agent).The catalysts were characterized by elemental analysis(CHN and X-ray fluorescence),X-ray diffraction,N2 adsorption-desorption,scanning electron microscopy,Fourier-transform infrared spectroscopy,and UV-Visible spectroscopy.The dual metal cyanide catalysts were used in several acid catalyzed multi-component coup...     

Metal Complexes of a Hexameric Network Tetrapyrazinoporphyrazine: II. Complexing Sorption Properties

Coordination of metal ions from aqueous solutions with metal complexes of a hexameric network tetrapyrazinoporphyrazine was studied. These compounds are complexing sorbents; their equilibrium coordination capacity largely depends on the metal occupying the coordination cavity of the porphyrazine fragments and on the external factors: kind of salt being coordinated, solution acidity, etc.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 6, 2005, pp. 1041–1045.Original Russian Text Copyright © 2005 by Korzhenevskii, Markova, Efimova, Koifman, Zelenov.     

Thermodynamics of interactions between lead(II) and cadmium(II) ions and azulene-based complexing polymer films

In order to understand the essential processes/interactions between the metal ions and modified electrodes which are based on complexing polymeric films, access to thermodynamic characteristics is compulsory. The paper enlarges the information concerning the sorption of metal ions within complexing polymer films, particularly based on azulene, which can be involved in metal detection sensors. Interactions between lead(II) or cadmium(II) ions and complexing polymer films have been studied using chemical preconcentration–anodic stripping method. The films have been obtained by controlled potential electrolysis in millimolar solutions of 4-azulen-1-yl-2,6-bis(2-thienyl)pyridine (L) in acetonitrile. PolyL films affinities towards these metal ions have been quantified at different temperatures by means of sorption isotherms. Parameters for sorption of lead(II) and cadmium(II) ions within polyL films have been calculated for Freundlich, Langmuir and Redlich–Peterson isotherms. The best fit was obtained when using Langmuir isotherm. The results evidence that lead ions are better sorbed than cadmium within polyL film. Thermodynamic parameters for the chemical sorption of lead(II) and cadmium(II) ions within polyL films have been calculated.     

Complexing properties of cation-exchangers grafted with carboxyl moieties

The complexing properties of CM-52, Olvagel-COOH, MacroPrep 50 CM, and hypercrosslinked polystyrene MN (carboxyl-grafted sorbents) toward Cu²⁺, Co²⁺, Ni²⁺, Cd²⁺, Zn²⁺, Mn²⁺, and Pb²⁺ have been studied. The optimal parameters for the sorption of these metal ions from solution have been determined. The pH effect on the ion uptake has been studied. The uptake is maximal at pHs higher than 5–6. When pH is lower than 2, the indicated ions are quantitatively desorbed. Olvagel-COOH is most selective toward these ions.     

Trends in Sorption Recovery of Platinum Metals: A Critical Survey

The major trends in research into the sorption recovery and separation of platinum metals are critically surveyed. The advantages and disadvantages are described for ion-exchange and complexing sorbents based on organic polymers, chemically modified silicas, sorbents with applied macrocyclic compounds, hybrid organomineral sorbents with supported polymers, molecular imprinted sorbents, solid-phase extractants based on ionic liquids, biosorbents, and other types of sorbents. The technological potentials of these sorbents are evaluated.     

Mn掺杂Ce0.7Zr0.3O2催化剂同时去除碳烟和氮氧化物的性能

采用柠檬酸络合燃烧法制备了一系列x%Mn/Ce0.7Zr0.3O2(x=0,5,10,15,30,50)复合金属氧化物催化剂,对其同时去除柴油机尾气中碳烟颗粒物(PM)和氮氧化物(NOx)反应的催化活性进行了评价,并采用XRD、低温氮吸附-脱附、H2-TPR、O2-TPD和原位漫反射红外光谱(in situ DRIFTS)等技术对催化剂的性能进行了表征。结果表明,不同含量Mn掺杂入铈锆固溶体中均形成了三元固溶体催化剂,在同时去除PM和NOx的催化反应中,固溶体催化剂的催化活性与其氧化能力直接相关。其中30%Mn/Ce0.7Zr0.3O2催化剂具有较好的同时去除PM和NOx的催化活性,催化去除PM的Ti和Tm分别为298和504℃,NO的转化率达到30.6%。结合O2-TPD和原位红外结果可知,30%Mn/Ce0.7Zr0.3O2表面吸附的超氧物种(O2-)及其与NO反应生成的硝酸盐物种(NO3-)是同时去除PM和NO反应的主要活性物种,进而指出PM和NO在30%Mn/Ce0.7Zr0.3O2表面反应过程中形成了异氰酸盐(-NCO)中间物种,在原位红外实验的基础上提出了30%Mn/Ce0.7Zr0.3O2复合氧化物催化剂同时去除PM和NOx的反应机理。     

OXIDATION OF HYDROCARBONS UNDER THE MILD CONDITIONS

The oxidation of organic substrates leads to the production of many functionalised molecules which are of great commercial and synthetic importance. The conventional mode of oxidation which involves stoichiometric ammount of Cr or Mn salts has been staked out because of the environmental hazadrous process. The transition to cleaner, safer, and more efficient plants is a new paradigm in the synthetic organic chemistry. Nowadays, hydrogen peroxide and oxygen as oxidizing agents were extreamely valuable and attractive. It is increasingly recognized, when polymers are used as supports for catalysts or organic reagents, the reactivity and selectivity of the supported catalysts or reagents may be seriously changed by so-called "polymer effects". As metal catalyzed oxidation of organic substrates with oxygen, we arc planing the incorporation of transition metals into polymer. In oxidaton organic compound has little resistant, so syntheses of organic-inorganic hybrid polymer from silica gel and montmorillonite by the modification with silane coupling reagents and the complexation of transition metal ions into hybrid polymer obtained above were investigated.     

In situ electrochemical complex formation for selected metal ions based on controlled release of the pyrrolidine dithiocarbamate ligand from polypyrrole polymer

A novel in situ electrochemical complex formation for selected metal ions has been developed. The scheme involves the use of polymeric material as a conducting agent into which the complexing agent pyrrolidine dithiocarbamate ligand is incorporated. The property of the polymer enables electrochemically controlled release of the reagent into a flowing solution. A dual-electrode arrangement in a thin layer transducer, the series dual-electrode detector, is used to release the ligand and detect it or its metal complex. The influence of the film prepared for ligand incorporation and the ion exchange process after polymer synthesis was studied. The film thickness for ligand incorporation and the negative potential required to trigger the ligand release were investigated. Finally, in flow injection analysis (FIA), the effects of the ionic strength of the supporting electrolyte and the flow rate on reagent release behavior and metal ion complexation were examined.