催化还原褪色光度法测定粉煤灰中微量铜

在ＰＨ５．０的ＨＡｃ－ＮａＡｃ缓冲休系中,痕量Ｃｕ（Ⅱ）催化抗坏血酸还原偶氮胭脂红Ｂ的褪色反应,褪色程度与Ｃｕ（Ⅱ）量在一定范围内线性相关。建立了测定痕量Ｃｕ（Ⅱ）的光度法,检出限为３．５＊１０＾－１１ｇ／ｍＬ,褪色程度与Ｃｕ（Ⅱ）量在０．０－２．０μｇ／Ｌ范围内符合比耳定律。本法结合Ｎ５３０－Ｎ５１０混合萃取剂萃取分离,测定了粉煤灰中的微量铜。     

催化光度法测定煤矸石中微量铜的研究

在乙酸－乙酸钠介质中痕量铜对抗坏血酸还原二溴对甲基偶氮羟（２－Ｂｒ－ｐＭＡＣ）褪色反应有催化作用,催化程度与Ｃｕ（Ⅱ）量线性相关。借此建立了测定痕量Ｃｕ（Ⅱ）的分光光度法。实验表明,有色溶液所最大吸收波长为５８６ｎｍ,方法检出限为０．０４８μｇ／Ｌ,Ｃｕ（Ⅱ）量在０￣０．８μｇ／５０ｍＬ范围内符合比耳定律,可用于测定煤矸石中的微量铜。     

萃取催化光度法测定痕量铜

研究了在ｐＨ５．５的弱酸性介质中,利用邻菲罗啉活化铜（Ⅱ）催化过氧化氢氧化邻氨基酚显色的指示反应,用萃取平衡控制反应时间,水相中邻氨基酚的浓度和反应程度,建立了萃取催化光度法测定痕量铜的新方法。方法的线性范围为０．０００５０￣０．１０ｍｇ／Ｌ,检测限为５．０×１０＾－７ｇ／Ｌ。用于水和粮食中痕量铜的测定,结果满意。     

锑（锡）—Ferron—Se（Ⅳ）络合吸附催化波研究及应用

在ｐＨ１．８的Ｈ２ＳＯ４－ＮａＡｃ缓冲溶液中，用单扫示波极谱法，Ｓｂ（Ⅲ）或者（Ｓｎ（Ⅳ）－７－碘－８－羟基喹啉－５－磺酸－Ｓｅ（Ⅳ）体系可产生灵敏的络合吸附催化波。锑、锡浓度分别在０．４～２００μｇ／Ｌ和０．８～１８０μｇ／Ｌ范围内与峰高呈线性关系，检测限分别为０．２μｇ／Ｌ和０．４μｇ／Ｌ，并用于工业废水，地下水和天然水中痕量锑和锡的测定，同时对电话性络合物的组成，极谱波的性质和电极过程机理也     

荧光法测定环境水中的痕量砷

建立了测定环境水中痕量砷的荧光新方法,在ＰＨ６．５－７．５的缓冲介质中,利用２′,７′－二氯荧光素（ＤＣＦ）作为荧光试剂,激发波长λｅｘ＝５１０ｎｍ,发射波长λｅｍ＝５２８ｎｍ下,测定痕量砷,亚砷酸根浓度在０．２５－３．５０μｇ／２５ｍＬ范围内,相对荧光强度差值与亚砷酸根浓度呈线性关系,检测限为０．１６μｇ／２５ｍＬ,用于检测自来水和池塘水中的痕量砷,回收率为９５％－１０５％。     

新荧光试剂—3—邻甲苯基—5—（2‘—羧基苯偶氮）绕丹宁的荧光性质研究

本文报道新荧光试剂－３－邻甲苯基－５－（２’－羧基苯偶氮）绕丹宁（３ＯＭＲＡＣＰ）的荧光特性，建立了荧光分析测定铜的方法，在ｐＨ５．６时，３ＯＭＲＡＣＰ与铜（Ⅱ）形成螯合物，并在λｅｘ／λｅｍ＝３０８ｎｍ／４０５ｎｍ产生强烈荧光，其荧光强度与铜（Ⅱ）的浓度在０．１～４．０×１０＾－２μｇ／ｇ范围内呈线性关系，检测限达５×１０＾－４μｇ／ｇ。测定了人发中的痕量铜，结果满意。     

Cu(Ⅱ)KIO_4胭脂红-1,10-菲罗啉体系催化动力学光度法测定人发中痕量铜

基于ｐＨ６．５ 的Ｎａ２ＨＰＯ４ＮａＨ２ＰＯ４ 缓冲介质中铜离子对高碘酸钾氧化胭脂红褪色反应的催化作用,提出了催化动力学光度法测定痕量铜的新方法。研究了该方法的适宜反应条件,方法的检出限为１．１×１０－ ７ｇ／ＬＣｕ（Ⅱ）,表观摩尔系数ε＝ ７．８×１０５Ｌ·ｍ ｏｌ－ １·ｃｍ － １,线性范围为０～０．５μｇ／１０ｍ ＬＣｕ（Ⅱ）,方法已用于人发中痕量铜的测定     

催化动力学分析法测定痕量铜

研究了在氨性介质中，Ｃｕ（Ⅱ）催化Ｈ２Ｏ２氧化噻嗪红Ｒ的退色反应，据此建立了催化动力学光度测定Ｃｕ（Ⅱ）的新方法，方法的线性范围为０．００５－０．５μｇ／２５ｍｌ。曾应用于水、猪肝和小麦粉标准物质中痕量铜的测定，获得满意结果。     

催化还原褪色光度法测定痕量铜的研究

本文在少量氯化钠存在下的磷酸－磷酸二氢钾缓冲溶液（ｐＨ＝２．７）中，以铜（Ⅱ）催化次磷酸钠还原罗丹明Ｂ褪色为指示反应，建立了痕量铜的动力学光度分析新方法，在沸水浴中加热反应１０ｍｉｎ，测定的线性范围在０～０．４０μｇ／２５ｍＬ铜（Ⅱ）回归方程为△Ａ＝１．９７５ｃ＋０．００３，相关系数为０．９９９９，以△Ａ＝０．０１计算得测定下限为０．００５μｇ／２５ｍＬ。方法应用于铅基合金，纯铅粉和标准镁合金中铜     

锑（锡）－Ferron－Se（Ⅳ）络合吸附催化波研究及应用

在ｐＨ１．８的Ｈ＿２ＳＯ＿４－ＮａＡｃ缓冲溶液中，用单扫示波极谱法，Ｓｂ（Ⅲ）或者Ｓｎ（Ⅳ）－７－碘－８－羟基喹啉－５－磺酸－Ｓｅ（Ⅳ）体系可产生灵敏的络合吸附催化波。锑、锡浓度分别在０．４～２００μｇ／Ｌ和０．８～１８０μｇ／Ｌ范围内与峰高呈线性关系，检测限分别为０．２μｇ／Ｌ和０．４μｇ／Ｌ，并用于工业废水、地下水和天然水中痕量锑和锡的测定。同时对电活性络合物的组成、极谱波的性质和电极过程机理也作了讨论和研究。     

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.