阴离子洗涤剂选择性电极电位滴定法测定石油磺酸钠

本文以阴离子洗涤剂选择性电极作指示电极,用电位滴定法测定石油磺酸钠的浓度。当浓度在20％左右时,相对偏差小于±1％,测定选矿尾水中痕量石油磺酸钠的相对偏差为±8.1％。本法操作简单,适宜于快速分析。     

Intercalation and Electrochemical Studies of Nitroprusside Anion into Zn-Al Layered Double Hydroxide

The aim of the present work was to investigate the synthesis,characterization and electrochemical properties of the nitroprusside anions (NP)into zinc and aluminium layered double hydroxides (LDHs). The materials were prepared by thecoprecipitation method under constant pH, followed by a hydrothermal treatment. Theprepared materials were characterised by a set of analysis methods, such as powderX-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry(TG), scanning electron microscopy (SEM) and cyclic voltammetry (CV). The resultsshowed that the electrochemical response of NP ions into LDH structure is similar to thatfound for complex ions free in solution. In addition, our results reveal the dependence ofthe electrochemical response on the nature of the supporting electrolyte, for either cationic oranionic species.     

反相悬浮与非均相水解法合成阴离子聚丙烯酰胺的研究

采用反相悬浮与非均相水解相结合的方法合成了分子量大于 １０７ 的阴离子聚丙烯酰胺（ＡＰＡＡ）。研究了水解度（ＨＤ）与水解时间及体系 叫的关系、不同水醇比（Ｖ＿水／Ｗ＿醇）条件下 ＨＤ与时间的关系，ＨＤ与温 度的关系，同时研究了ＡＰＡＡ在溶液中的粘性行为，讨论了分子量的 测定方法。     

Fibre-optic potassium ion sensors based on a neutral ionophore and a novel lipophilic anionic dye

A novel lipophilic anionic dye, N-2,4-dinitro-6-octyloxyphenyl-2′,4′-dinitro-6′-trifluoromethylphenylamine (LAD), was synthesized. On deprotonation at neutral Ph it forms anions and brings about a change in the absorption spectrum in the visible region. This anionic dye was incorporated into a poly(vinyl chloride) matrix membrane with dibenzo-18-crown-6 (DB18C6) or valinomycin, which are K⁺-selective neutral ionophores. An optical K⁺ sensor was prepared using the polymeric membrane set 1 mm apart from the tip of a bifurcated optical fibre with a cylindrical plastic support. This sensor could detect a wide range of K⁺ concentrations (10^?6?1 M K⁺ for the DB18C6-based sensor, 10^?8?10^?2 M K⁺ for the valinomycin-based sensor) at Ph 7.0 by measuring the absorbance change at 513 nm. The factors that influence the response sensitivity of the sensor are discussed theoretically.     

The fundamental nature and role of the electrostatic potential in atoms and molecules

 A variety of atomic and molecular properties can be expressed in terms of the electrostatic potential. These include energies, covalent and anionic radii, electronegativities (chemical potentials) and a variety of properties that depend upon noncovalent interactons. We present a survey of such relationships, which may be exact or approximate; they may involve the potential in three-dimensional space, along the axes between bonded atoms, at nuclei or on molecular surfaces. Thus, the electrostatic potential, which is rigorously related to the electronic density by Poisson's equation, can be regarded as, effectively, another fundamental determinant of atomic and molecular properties. Received: 6 March 2002 / Accepted: 15 May 2002 / Published online: 29 July 2002     

Anionic polymerization of methyl methacrylate initiated with molybdenum and tungsten chloride/organolithium/triisobutylaluminum systems

Molybdenum chloride (MoCl₅ or 1a ) and tungsten chloride (WCl₆ or 1b )/phenyllithium (PhLi)/triisobutylaluminum (iBu₃Al) systems were found to be quite effective for controlling the anionic polymerization of methyl methacrylate (MMA), affording high molecular weight poly(methyl methacrylate)s (PMMAs; number‐average molecular weight > 100,000) with narrow molecular weight distributions (weight‐average molecular weight/number‐average molecular weight < 1.25) quantitatively at 0 °C for 1 h in toluene. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) analyses of PMMAs obtained with the 1a and 1b /organolithium (RM; n‐butyllithium, PhLi)/iBu₃Al systems revealed that the initiation of MMA with the systems occurred by a nucleophilic attack of H^? to the monomer. In addition, the MALDI‐TOF MS analyses indicated that the presence of iBu₃Al was responsible for the controlled polymerization by improving the uniformity of the polymerization with respect to initiation and termination and by preventing a backbiting reaction. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4302–4315, 2002     

高比表面CexZr1-xO2复合氧化物的制备及表征

分别采用共沉淀法和阴离子表面活性剂模板法制备了Ce_xZr_1-xO₂复合氧化物。采用XRD、AFM、FTIR以及N₂吸附-脱附等方法对样品进行了表征。结果表明，共沉淀法合成的样品在500 ℃煅烧2 h后，生成了立方相Ce_0.75Zr_0.25O₂和四方相Ce_0.5Zr_0.5O₂固溶体，比表面积为62.1 m²·g^-1，孔体积为0.097 cm³·g^-1；以阴离子表面活性剂十二烷基苯磺酸钠(SDBS)为模板剂，乙二胺为助模板剂合成的样品在500 ℃煅烧2 h后，生成了纯四方相Ce_0.5Zr_0.5O₂固溶体，比表面积为180 m²·g^-1，孔体积为0.182 cm³·g^-1。结果表明，以阴离子表面活性剂SDBS为模板剂，可以合成高比表面积且具有介孔结构的Ce_0.5Zr_0.5O₂复合氧化物；加入乙二胺作为助模板剂可明显的提高比表面积和孔体积。     

Consecutive carbon-carbon bond formation approach in tandem cyclization reactions

The conventional tandem cyclization reactions involve the formation of alternating carbon-carbon bonds, whereas the newly developed cyclization reactions involve the formation of consecutive carbon-carbon bonds, in which N-aziridinylimines have been utilized as geminal radical acceptor and donor equivalents in a single operation. This unprecedented tandem cyclization approach becomes feasible by the successful generation of 5- and 6-membered ring radicals by radical cyclizations of N-aziridinylimines. The same notion can be applied to the anionic cyclizations of N-aziridinylimines, thereby allowing anionic consecutive carbon-carbon bond formation. This approach has great synthetic potential, particularly for the construction of quaternary carbon centers, and it provides highly efficient routes for the synthesis of natural products.     

碳棒涂膜电极流动注射法测定环境水样中的阴离子表面活性剂

采用自制碳棒PVC涂膜阴离子表面活性剂电极 ,建立了测定环境水样中阴离子表面活性剂的流动注射电位分析新方法。电极膜最佳组成 :THDA DBS 5mg ,DBS 0 .4mL,NB 0 .3mL ,PVC粉 0 .2g;电极线性响应范围 1× 1 0 - 3～ 1× 1 0 - 6 mol L。以 0 .0 1mol LKCl溶液作载流 ,流速 6.6mL min ,进样体积 2 0 0 μL,分散管长 2 0cm ,采样频率 5 0～ 80次样 h。测定 1 0 - 3、1 0 - 4 mol LDBS溶液 ,RSD≤ 3 .1 2 % (n=7) ,回收率 88.0 %～ 1 0 5 .0 %。电极易制作 ,成本低 ,FIA流路简单 ,操作方便 ,且克服了直接电位法电位飘移大的缺点 ,有较好的实用性     

Preparation of polysaccharide–polymethacrylate hybrid materials by radical polymerization of cationic methacrylate monomer in the presence of anionic polysaccharide

This article describes preparation of polysaccharide–polymethacrylate hybrid materials by means of free‐radical polymerization of a cationic methacrylate monomer in the presence of anionic polysaccharides. In particular, synthesis of the hybrid material composed of carboxymethyl cellulose (CMC) and a cationic polymethacrylate, i.e. poly(2‐aminoethyl methacrylate) is disclosed. The formation of the materials was achieved by radical polymerization of 2‐aminoethyl methacrylate hydrochloride (AEMA‐HCl) in aqueous solution of CMC. The insoluble material was formed and the structure was determined by the IR spectra and elemental analysis to be composed of CMC and polymethacrylate. Thermal analyses such as thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) were performed to confirm the network structure of the material. The dehydrative amidation occurred by heating the material at 200°C, giving rise to the new hybrid material hybridized by the amide linkages. Copyright © 2007 John Wiley & Sons, Ltd.