Synthesis and analytical characterization of a chelating resin loaded with dithizone

A chelating sorbent loaded with dithizone was obtained by chemical reaction with styrene-DVB (5%) copolymer as matrix. The analytical characteristics of the sorbent were established and optimum sorption conditions for Ag, Cu, Cd, Pb, Ni, Co and Zn under static and dynamic conditions determined. The sorbent was applied to determination of copper and lead in river water and of silver in electrolytic copper. After separation of traces of metals on the sorbent and desorption with hydrochloric acid, the metals were determined in the effluent by atomic-absorption spectrophotometry.     

Preparation,properties and analytical application of silica with chemically grafted hydroxamic acid groups

The synthesis of silica chemically modified with propanohydroxamic acid groups and salicylhydroxamic acid is described. Sorption of 13 metal ions is studied as a function of pH. The composition of the sorbed complexes is determined and the apparent stability constants of the complexes in the sorbent phase are calculated. A correlation between the stabilities of the complexes in the sorbent phase and in aqueous solution is observed in some cases. Some analytical applications of the sorbents are demonstrated: trace amounts of elements can be concentrated from large volumes; molybdenum(VI) and zirconium(IV) can be separated from 10⁴-fold amounts of accompanying elements, and vanadium(V) can be determined in the sorbent phase by using diffuse reflection and photoacoustic spectrometric techniques.     

Synthesis and analytical properties of an n-phenyl-hydroxamic acid resin

A procedure for attaching N-phenylhydroxamic acid groups to Amberlite XAD-4 is described. The extraction of 20 metal ions from 2 M hydrochloric acid by this resin is discussed. Conditions for the quantitative extraction and back-extraction of 9 ions are reported. The results are compared with work on solvent extraction with N-phenylbenzohydroxamic acid.     

Synthesis, characterization and analytical application of a new inorganic cation exchanger—Titanium(IV) molybdophosphate

A novel polyoxometalate-cation exchanger, titanium(IV) molybdophosphate (TMP) has been synthesized under varying conditions. The material was characterized by X-ray diffraction, infrared spectroscopy, inductively coupled plasma and thermogravimetry techniques. Its stability was investigated in water, dilute acids, alkaline solutions, and high temperature up to 750 °C. Ion-exchange capacity and distribution coefficients (K_d) for twenty-nine radionuclides and metal ions have been determined. It was found that the TMP has high affinity for Cs⁺, Sr²⁺, UO₂²⁺, Ba²⁺, Pb²⁺, Tl⁺, Zn²⁺, Rb²⁺ and Zr⁴⁺ ions. The results of binary separation of metal ions showed that TMP can be potentially useful for analytical applications.     

Preparation, characterization and analytical application of a hybrid organic-inorganic silica-based monolith

In the present study, a mercapto groups-incorporated hybrid silica-based monolith, which consists of a continuous porous silica backbone, was successfully synthesized by sol-gel technology. The hybrid silica monolith was characterized by various techniques, such as elemental analysis, scanning electron microscopy, diffused infrared spectroscopy and low temperature nitrogen desorption/adsorption measurements. The results showed that the monolith contains high sulfur content (up to 3.05%) with a hierarchical porous structure (throughpores and mesopores) and large specific surface area (467 m(2)/g). Due to the favorable chemical reactivity of mercapto pendant moieties, the hybrid monolith can be facilely derivatized to yield various functional groups. In this study, they were oxidized by hydrogen peroxide (30%, w/w) to produce sulfonic acid groups, which exhibited excellent cation-exchange capability. The application of this material is demonstrated by in-tube microextraction of anaesthetics followed by capillary electrophoretic separation. The monolith can be effectively applied to purify and enrich the target analytes in human urine.     

荧光试剂SPAEC的合成及分析化学特性研究

合成了新荧光试剂2-(5'-磺基-2'-苯酚-1'-偶氮)-5-乙氨基-4-甲酚(SPAEC)。用等色点光度法测得试剂的离解常数为pK1=3.42, pK2=5.46, pK3=7.99。考察了SPAEC与金属离子的螯合显色和荧光反应; 建立了测定镓、铝的反应条件, 在PH3.8-5.4或PH4.0-5.5的乙酸缓冲介质中均形成:1型具荧光活性的有色螯合物, 可相应测定15-150ppb镓及1.5-30ppb铝, 试用于半导体及合金分析。研究了Kalman滤波荧光光度法, 实现了镓与铝的同时测定, 所适应的浓度比例范围为40:1(0)-1(0):14。     

Synthesis, characterization and properties of the polysiloxane-based episulfide resin

The polysiloxane episulfide resin (PSER) was synthesized through replacement of the oxygen atoms in 1,3,5,7-tetra-(3-glycidoxypropyl) tetramethylcyclotetrasiloxane (TGCS) with sulfur atoms using potassium thiocyanate (KSCN). It was characterized by FT-IR, ¹H NMR, MS and elemental analysis. The PSER resin was a low viscosity liquid, stable at room temperature. The polysiloxane episulfide resin was very reactive: a mixture of PSER and isophorondiamine gelated in a few seconds at room temperature. When m-phenylenediamine (m-PDA) or 2-ethyl-4-methylimidazole (2E4MZ) was used as curing agent, PSER exhibited higher reactivity compared with the parent polysiloxane epoxy resin. The reaction heat of the PSER resin was much lower in comparison with TGCS. The cured polysiloxane episulfide resin showed higher glass transition temperature and much lower water absorption, while the thermal stability was lower. It was found that methylhexahydrophthalic anhydride (MeHHPA) is not effective for curing the episulfide resin, although it is commonly used for curing epoxy resins.     

A new chelating ion-exchanger containing p-bromophenylhydroxamic acid as functional group-IV: column separations on a hydroxamic acid resin

A new chelating resin based on macroreticular acrylonitrile-divinylbenzene copolymer and containing hydroxamic acid functional groups has been synthesized. It is highly stable in acidic and alkaline solutions. The sorption characteristics of Cu(II), Cd(II), Pb(II), Zn(II), U(VI), Cr(VI), V(V), Co(II), Ni(II), Ca(II) and Mg(II) have been investigated over the pH range 1.0-6.0. The effect of various electrolytes at different ionic strengths on the K(d) values for Cu(II), Cd(II), Pb(II) and Zn(II) has been studied systematically. Chromatographic separations of copper(II) and nickel(II) from cobalt (II), and of uranium(VI) from chromium(VI) by selective sorption at controlled pH, have been developed. The ion-exchanger can be used for purification of inorganic salts, and analysis of brass and bauxite.     

Synthesis of a novel fluorescent probe and investigation on its interaction with nucleic acid and analytical application

A novel fluorescent probe N-(N-(2-(4-morpholinyl)ethyl)-4-acridinecarboxamide)-alpha-alanine (N-(N-(ME)-4-ACA)-alpha-ALA) was synthesized. The structure was characterized by 1H NMR, MS, elemental analysis, fluorescent and ultraviolet spectra. This new compound exhibited high binding affinity to DNA, intense fluorescence and high water solubility. Experiment indicated that the fluorescent intensity was quenched when DNA was added. A method for DNA determination based on the quenching fluorescence (lambda(ex)=258nm, lambda(em)=451nm) of N-(N-(ME)-4-ACA)-alpha-ALA was established. Under optimal conditions (pH 7.2, CN-(N-(ME)-4-ACA)-alpha-ALA)=3 x 10(-6) mol L(-1)), the linear range is 0.1-4.0 microg mL(-1) for both fish semen (fsDNA) and calf thymus DNA (ct-DNA). The corresponding determination limits are 4.6 ng mL(-1) for fsDNA and 5.1 ng mL(-1) for ct-DNA, respectively. The relative standard deviation is 1.0%. Thus this compound can be used as a DNA fluorescent probe. The experiments proved that the interaction mode between N-(N-(ME)-4-ACA)-alpha-ALA and DNA was groove binding. The modified Rosenthal's graphical method gave the binding constant of 1.0 x 10(6) L mol(-1) and a binding size of 0.31 base pairs per bound drug molecule.     

Synthesis and characterization of a new resin functionalized with 2-naphthol-3,6-disulfonic acid and its application for the speciation of chromium in natural water

A polystyrene divinyl benzene (8%) copolymer has been functionalized by coupling it through NN group with 2-naphthol-3,6-disulfonic acid (NDSA). The resulting resin has been characterized by elemental analysis, thermogravimetric analysis and infrared spectra. The hydrogen ion, water regain and metal ion capacities of the resin have been determined. Two forms of chromium show different exchange capacities at different pH values, viz. Cr(III) selectively retained at pH 6.5 whereas Cr(VI) retained at pH 1.5. Hence complete separation of the two forms of chromium is possible. The kinetic studies show that the exchange of Cr(III) and Cr(VI) follows second-order kinetics. The metal ion concentration was measured by flame atomic absorption spectrometry. The method has been successfully applied for the speciation of chromium in natural water samples.     

Synthesis, characterization, thermal properties and flame retardancy of a novel nonflammable phosphazene-based epoxy resin

Hexakis(4-hydroxyphenoxy)-cyclotriphosphazene (PN-OH) was synthesized through nucleophilic substitution of the chloride atoms of hexachlorocyclotriphosphazene and reduction of the aldehyde groups, and its chemical structure was characterized by elemental analysis, ¹H and ³¹P NMR, and Fourier transform infrared (FTIR) spectroscopy. A new phosphazene-based epoxy resin (PN-EP) was successfully synthesized through the reaction between diglycidyl ether of bisphenol-A (DGEBA) and PN-OH, and its chemical structure was confirmed by FTIR and gel permeation chromatography. Four PN-EP thermosets were obtained by curing with 4,4′-diaminodiphenylmethane (DDM), dicyandiamide (DICY), novolak and pyromellitic dianhydride (PMDA). The reactivity of PN-EP with the four curing agents presents an increase in the order of DDM, PMDA, novolak and DICY. An investigation on their thermal properties shows that the PN-EP thermosets achieve higher glass-transition and decomposition temperatures in comparison with the corresponding DGEBA ones while their char yields increase significantly. The PN-EP thermosets also exhibit excellent flame retardancy. The thermosets with novolak, DICY and PMDA achieve the LOI values above 30 and flammability rating of UL94 V-0, whereas the one with DDM reaches the V-1 rating. The nonflammable halogen-free epoxy resin synthesized in this study has potential applications in electric and electronic fields in consideration of the environment and human health.     

Synthesis,characterization, and application of helical polymers

This review mainly describes the asymmetric synthesis of optically active polymers with helical conformation. Bulky methacrylates such as triphenylmethyl methacrylate and 1-phenyldibenzosuberyl methacrylate give one-handed helical and optically active polymers with almost perfectly isotactic main chain conformation by polymerization with chiral anionic initiators. The radical polymerization and copolymerization of these monomers under chiral conditions also afford optically active polymers with prevailing one-handed helicity. N, N-Disubstituted acrylamides also give optically active, helical polymers in the asymmetric anionic polymerization. Optically active polyisocyanates with a prevailing one-handed helical structure have been prepared in the copolymerization of an achiral isocyanate with a small amount of an optically active isocyanate and also in the polymerization of alkyl and aromatic isocyanates with optically active lithium alkoxide or amide compounds. The existence of a stable helical structure for polychloral has been successfully proved with the helical oligomers of chloral. One-handed helical polyisocyanides have been prepared by helix-sense-selective polymerization of bulky isocyanides and also by the cyclopolymerization of a 1, 2-diisocyanobenzene derivative with the Pd complex of a one-handed helical oligomer.     

Synthesis and characterization of novel multifunctional epoxy resin

A novel multifunctional epoxy resin was synthesized by polyphenol and epichlorohydrin.The structure and molecular weight ofthe multifunctional epoxy were characterized by FTIR and ESI-MS.DSC and DMTA were used to investigate the thermal propertyof multifunctional epoxy cured by DDS.The thermal resistance of the synthesized multifunctional epoxy was much better than astandard diglycidyl ether of bisphenol-A epoxy.     

Synthesis and characterization of ureido-containing MQ silicone resin

Abstract

Ureido-containing MQ silicone resin (U-MTQ) was synthesized by the hydrolysis and co-condensation reaction of ethyl silicate, ureido silane, hexamethyldisiloxane, and divinyltetramethyldisiloxane under the catalysis of hydrochloric acid. U-MTQ was characterized by FT-IR, ¹H-NMR, ²⁹Si-NMR, GPC and TGA. The influences of M/Q molar ratio and hydrochloric acid content on the yield and structure of U-MTQ were investigated. The results showed that the M/Q molar ratio of the product calculated from the ²⁹Si-NMR spectrum was much smaller than that in the feed. As M/Q molar ratio in the feed increased, the molecular weight and its distribution index of U-MTQ decreased, and Si-OH content of U-MTQ also decreased, while the structural regularity of U-MTQ was enhanced. With HCl content increasing, the molecular weight and its distribution index of U-MTQ decreased, but the Si–OH content and structural regularity increased. Meanwhile, the yield first increased and then decreased, and reached the highest value of 71.9% when HCl content was 2.10%. Compared with MQ, the onset weight loss temperature of U-MTQ decreased from 237?°C to 158?°C, and the residue at 900?°C increased from 3.5% to 29.5%.     

Synthesis of a pyrano[2,3-b] pyridine with vinylogous hydroxamic acid structures

A new, two step synthesis of a pyrano[2,3-b]pyridine derivative 5 is described. Dehydro-acetic acid and N,N-dimethylformamide dimethylacetal was condensed to form 2 . Compound 2 was converted into 5 by reaction with hydroxylamine which opens the lactone ring.     

Synthesis and characterization of metal-incorporated aniline formaldehyde resin modified by amino acid for antimicrobial applications

Advances in metal incorporated resins are now an active field of research. To develop resin having better antimicrobial and thermal activity, a series of metal-chelated resins have been synthesized by the condensation of (4-aminobenzene-1,3-diyl)dimethanol with 2,6-diaminohexanoic acid in alkaline medium and then this polymeric ligand further reacts with transition metal ions forming various coordination polymers. (4-Aminobenzene-1,3-diyl)dimethanol was initially prepared by the reaction of aniline and formaldehyde in 1?:?2 molar ratio in alkaline medium. The analytical data reveal that the polymer metal complexes of Mn(II), Co(II), and Ni(II) are coordinated with two water molecules, which are further supported by FTIR spectra and TGA data. Comparative analyses of the polymer metal complexes in thermal curves show better thermal stability than the polymeric ligand. Since these resins are relatively stable at high temperatures, they can be used for medical and biomaterial applications requiring thermal sterilization, solvent-resist coating materials because of their insoluble nature, and antifouling coating materials owing to antimicrobial activity in ?elds such as life-saving medical devices and the bottoms of ships.     

Synthesis and characterization of a novel cycloaliphatic epoxy resin starting from dicyclopentadiene

A novel tri-functional cycloaliphatic epoxy resin was synthesized starting from dicyclopentadiene. The chemical structures of the resultant epoxy resin and its precursor were characterized with FTIR spectroscopy, EEW, ¹H NMR and Mass spectrographic analyses. The thermal and mechanical properties of the resulting polymer were evaluated with differential scanning calorimeter (DSC), thermo-gravimetric and thermal mechanical analysis. Compared to that of the common cycloaliphatic epoxy resin ERL-4221, the cured polymer of the novel epoxy resin exhibited lower thermal degradation temperature with much higher char yield and similar thermal expansion coefficient. These excellent overall performances make it a promising packaging material.     

一类高速固化光敏树指的合成及表征

光敏树脂具有节约能源、污染小、固化速度快、生产效率高、适宜流水线生产等优点,近年来得到了快速发展[1 4]。对于光敏树脂,固化速度是最重要的指标之一,它直接关系到生产效率、能源消耗以及固化树脂的性能。本文采用多元脂肪胺及含多元双键的丙烯酸酯通过迈克尔加成反应合成了一类UV快速固化光敏树脂,粘度较低,成膜性好,成本较低,在实际生产中有广阔的应用前景。1　实验部分1 1　试剂仪器乙二胺(AR,中国医药上海化学试剂公司);三乙烯四胺(AR,宜兴试剂三厂);三丙二醇二丙烯酸酯(TPGDA,工业品);三羟甲基丙烷三丙烯酯酯(TMPTA,工…