新体系Fe（Ⅲ）－KIO＿4－偶氮氯磷Ⅲ催化动力学光度法测定食品中痕量铁的研究

研究了在硫酸介质中，痕量Ｆｅ（Ⅲ）催化高碘酸钾氧化氨氯磷Ⅲ的褪色反应及其动力学条件。本法检测限为８．７８×１０￣（０９）ｇ／Ｌ，测Ｆｅ（Ⅲ）范围０～１．４μｇ／１０ｍＬ，采用硫基葡聚糖凝胶分离富集，使本法选择性大大提高，建立了一种高灵敏、高选择性测定痕量Ｆｅ（Ⅲ）的新方法，用于食品中痕量Ｆｅ（Ⅲ）的测定，结果满意。     

新体系Fe（Ⅲ）—KIO4—偶氮氯膦Ⅲ催化动力学光度法测定食品痕量铁的…

研究了在硫酸介质中，痕量Ｆｅ（Ⅲ）催化高碘酸钾氧化氮氯膦Ⅲ的褪色反应及其动力学条件。本法检测限为８．７８×１０＾－９ｇ／Ｌ，测Ｆｅ（Ⅲ）范围０－１．４μｇ／１０ｍＬ，采用巯基葡聚糖凝胶分离富集，使本法选择性大大提高，建立了一种高灵敏、高选择测定痕量Ｆｅ（Ⅲ）的新方法，用于食品中痕量Ｆｅ（Ⅲ）的测定，结果满意。     

催化褪色光度法测定微量锰（Ⅱ）的研究

本文研究在硫酸介质中，锰（Ⅱ）催化ＥＤＴＡ还原重铬酸银，而使之褪色的新指示反应。确定了催化褪色反应动力学条件，锰（Ⅱ）的浓度在０－０．４μｇ／ｍｌ范围内，工作曲线呈良好的线性关系，检测限为０．０１１μｇ／ｍＬ，该方法用于天然水及污水中锰的测定，获得满意结果。     

催化动力学光度法测定痕量铁的研究

本文研究了在稀硫酸介质中铁催化过氧化氢氧化胭脂红的褪色反应及其动力学条件，测定了反应级数和表现活化能，建立了测定痕量铁的新方法。该方法的检出限为０．２５ｎｇ／ｍＬＦｅ，线性范围为０～０．４μｇ／２５ｍＬＦｅ，方法简便、快速、灵敏度高。应用于水及食品中痕量铁的测定，结果满意。     

重铬酸钾氧化偶氮胂Ⅲ褪色催化光度法测定痕量钴的研究

在醋酸－醋酸钠缓冲介质中痕量钴（Ⅱ）对重铬酸钾氧化偶氮胂Ⅲ褪色反应有显著的催化作用，催化反应的表现活化能为２５．６２ｋＪ．ｍｏｌ＾－１，据此建立了测定痕量钴的催化动力学分析法，线性范围为０～３５０ｎｇ．ｍＬ＾－１，检出限为２．０ｎｇ．ｍＬ＾－１（Ｃｏ），除Ｆｅ（Ⅱ）外，其余常见共存离子基本不影响钴的测定，本法重现性较好，用于测定人发，茶叶，土壤和废水中钴的含量，结果满意。     

催化褪色法测定痕量硒（Ⅳ）的研究

本研究发现，在盐酸介质中，Ｓｅ（Ⅳ）作活化剂，Ｐｄ~（２＋）催化次磷酸钠与甲基红的褪色反应。同时研究了反应动力学条件，建立了测定痕量Ｓｅ（Ⅳ）的新方法。方法检测限为４．８×１０~（－５）μｇ／ｍＬＳｅ（Ⅳ），测定范围为０～０．０１μｇ／ｍＬＳｅ（Ⅳ）。用于测定人发中的痕量Ｓｅ（Ⅳ），获得了满意结果。     

催化褪色光度法测定痕量钛的研究

本发现钛（Ⅳ）在稀硫酸介质中催化孔誉绿与碘化钾、碘酸钾之间的褪色反应，建立了褪色反应速率方程式和测定痕量钛（Ⅳ）的新方法。方法检测限为３．４ ×１０＾－１０ｇＴｉ（Ⅳ）／ｍＬ，测定范围为０～１．０μｇ／２５ｍＬＴｉ（Ⅳ）。用于测定人发中的微量元素钛的含量，获得了满意结果。     

新显色剂邻羧基苯基偶氮桑色素褪色光度法测定微量铁的研究

本文研究了新显色剂基苯偶氮桑色素与铁（Ⅲ）在ｐＨ５．６的缓冲溶液中的褪色反应，实验结果表明，利用此褪色反应测定铁（Ⅲ）其灵敏度高，表观摩尔吸光系数达３．１５×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，线性范围０～０．１μｇ／２５ｍＬ，检测限为：１．８×１０＾－１０ｇ／ｍＬ。应用于黑色食品中微量铁的测定，获是了满意的结果。     

催化光度法测定痕量铁的研究──Fe（Ⅲ）－对乙酰基偶氮胂－H＿2O＿2体系

本文基于在弱酸性介质中及活化剂α，　α－联吡啶存在下，痕量铁（Ⅲ）对过氧化氢氧化对乙酰基偶氮胂的反应有强烈的催化作用，建立了催化光度法测定痕量铁的新方法。该法灵敏度为１；１４×１０￣（－１１）ｇ／ｍＬ，测定范围为０～０．１０μｇ　Ｆｅ￣３＋／２５ｍＬ，表观活化能为８２．２４ＫＪ／ｍｏｌ。应用于大米、小米和小麦中痕量铁的测定，结果满意。     

抑制-桑色素褪色光度法测定痕量铁(Ⅲ)

１　引　言 测定痕量铁有桑色素（Ｒ）光度法（检测下限为０．１４ ｇ／ｇ）、萃取催化光度法（检出限１．６×１０－７ｇ／Ｌ）等。研究发现,基于ＮａＯＨ介质中,溴化十六烷基三甲铵（ＣＴＭＡＢ,下同）作为增稳剂时,Ｆｅ（Ⅲ）能抑制Ｈ２Ｏ２氧化桑色素的褪色反应。据此建立了一种高灵敏测定痕量铁的新方法。该方法灵敏度（检出限 ４．０×１０－９ｇ／Ｌ）高,无需萃取,操作简便,选择性好。未见抑制桑色素褪色光度法测定痕量铁的报道。２　实验部分２．１仪器及试剂 ７２３型可见分光光度计（上海分析仪器总厂）,７２２型光栅分光…     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.