铁催化剂在碳—氧反应中的热重研究

采用动态TG－DTG，研究了铁催化剂的制备方法、前驱化合物的 种类及 热处理对其在碳－氧反应中催化活性的影响。观察到在干混法制备催化剂时，所用铁盐分解温度越低活性越高。此外还发现，热处理可明显提高由分解温度高的含氧铁盐制备的 催化剂的活性，但对于不含氧铁盐和分解温度低的含氧铁盐无影响。     

Preparation of a thermally phase-separating copolymer,poly(N-isopropylacrylamide-co-N-acryloxysuccinimide), with a controlled number of active esters per polymer chain

N-isopropylacrylamide and N-acryloxysuccinimide have been copolymerized in various mixtures of terrahydrofuran and toluene using azobisisobutyronitrile as initiator. Polymerization has been conducted for 24 h at 50°C under a slightly positive pressure of nitrogen. The copolymers were assayed for active ester content by measuring the UV absorbance (259 nm) of N-hydroxysuccinimide anion, generated by reacting the copolymers with N-isopropylamine in dimethylformamide and dissolving the resulting mixture in 0.1M HEPES buffer, pH 7.5. The molecular weight and its distribution have been estimated by gel permeation chromatography. The active ester content was found to be equivalent to the comonomer feed ratio, and the major factor controlling the molecular weight was the ratio of tetrahydrofuran to toluene. Thus, the number of active esters per polymer chain could be controlled by adjustment of the comonomer feed ratio and the ratio of tetrahydrofuran to toluene. Monomer reactivity ratios for copolymerization of N-isopropylacrylamide with N-acryloxysuccinimide were also estimated. These copolymers are useful for immobilizing binding ligands such as antibodies for subsequent thermally induced precipitation immunoassays and bioseparation processes.     

3,4—亚甲二氧基苯甲酸锡酯的合成及表征

３，４－亚甲二氧基苯甲酸及其取代物与三苯基氢氧化锡或二丁基化锡反应合成了５个锡酯，通过元素分析，ＩＲ和＾１ＨＮＭＲ对其进行了表征。     

Oxidative coupling of methane over Sr?Ti, Sr?Sn perovskites and corresponding layered perovskites

The layered perovskites Sr₂TiO₄ and Sr₂SnO₄ are more active and selective for the oxidative coupling of methane at 1073 K than the corresponding perovskites SrTiO₃ and SrSnO₃. The role of the surface oxygen species for this reaction is discussed.     

一类新偶氮试剂的研究：Ⅴ.HQSAH催化荧光法测定Mn（Ⅱ）

基于Ｍｎ（Ⅱ）对试剂２－（８＇－羟基喹啉－５＇－磺基－７＇－偶氮基）－１－羟基－８－氨基一萘二磺酸（以下简称ＨＱＳＡＨ）分解反应的催化作用，提出了锰的荧光催化动力学分析新方法，其λｅｘ／ｅｍ＝２３０／４１５ｎｍ，适宜酸度范围为ｐＨ１１．０～１２．０，Ｍｎ（Ⅱ）含量在０～０．０８μｇ／ｍＬ呈线性关系，该法用于分析铸造铝合金中的痕量锰，效果良好。还初步探讨了反应机制，确定了反应动力学方程，测定了反应速率和活化能。     

原子发射光谱分析

本文是《分析试验室》期刊单年度定期评述中关于原子发射光谱分析的第三篇综述文章。文中对１９９３－１９９４年期间我国在ＡＥＳ领域所取得的主要进展作了简要的评述。评述内容包括基础理论、应用研究、仪器研制、新方法建立以及一般样品分析。研究领域主要涉及到电感耦合等离子体原子发射光谱法，微波等离子体原子发射光谱法，电弧和火花原子发射光谱法，辉发放电原子发射光谱法和亚稳态能量转移光谱法等。引用文献２１１篇。     

Rapid and sensitive spectrofluorimetric determination of trace amounts of Hg(II) with o-vanillin-8-aminoquinoline

The fluorimetric determination of mercury ions with o-vanillin-8-aminoquinoline (OVAQ) in aqueous solutions was investigated. Hg(II) could react with the fluorescent reagent OVAQ (λ_ex/em = 278/314 nm) to form a nonfluorescent complex in an ethanol-water medium of pH 6.00. The linear range of the proposed method was from 2.5 to 80 μg/L, and the detection limit was 0.80 μg/L. The interferences of 24 foreign ions were also studied. The method was successfully applied to the determination of Hg(II) in sludge. The text was submitted by the authors in English.     

若干3d过渡金属的硫代脯氨酸配合物

合成了七个新的过渡金属的硫代脯氨酸(tcH)配合物,它们分别是:[M(tc)_2](M=Mn(Ⅱ),Co((Ⅱ))和Ni(Ⅱ)),[Ni(tc)(Ac)(H_2O)],[Ni(tc)(tcH)(H_2O)]NO_3·H_2O,[Ni(tc)(Py)_2(H_2O)NO_3和[Fe(tc)_2(Cl)(H_2O)]。上述配合物的磁化率,摩尔电导,热量分析,红外及电子光谱数据表明,它们都具有八面体构型,tcH主要通过亚氨氮和羧基氧原子与金属键合。文章对这些配合物的可能结构作了初步的讨论。     

The oxygen reduction reaction at silver electrodes in high chloride media and the implications for silver nanoparticle toxicity

The oxygen reduction reaction (ORR) at neutral pH in various aqueous chloride-containing solutions was investigated voltammetrically. In particular, the ORR was performed in high chloride containing aqueous media including authentic and synthetic seawater under oxygen saturated conditions and compared with that in aqueous nitrate and perchlorate media. The experimental voltammograms revealed a two-electron process forming hydrogen peroxide in low chloride media. In contrast, high concentration chloride solutions, including both synthetic and authentic seawater showed an increase of overpotential, accompanied by a splitting of the voltammetric peak into two one-electron features indicating the formation of superoxide in the first step and its release from the silver-solution interface. The implications for silver nanoparticle toxicology are discussed given the markedly greater toxicity of superoxide over peroxide and the high levels of chloride in biological media as well as in seawater.

Superoxide produced at silver electrode in seawater.     

First alkyl radical additions to (eta(6)-arene)tricarbonylmanganese complexes

[reaction: see text] Reactions of alkylmercury chlorides with arene manganese tricarbonyl complexes in the presence of NaI led to the formation of the addition-reduction products. The mechanism was postulated to be the alkyl radical addition to ArMn(CO)3+ cation to form the corresponding 17 valence electron intermediate, which was then reduced by alkylmercury chloride via a singlet electron transfer process to afford the product and regenerate an alkyl radical.