乙基紫萃取光度法测定铜烟灰中铼

１引言 实验研究了几种碱性染料在不同介质条件下的显色反应和萃取条件,在ｐＨ＝２．４的Ｎａ２ＨＰＯ４－柠檬酸介质中,乙基紫与ＲｅＯ４－形成蓝绿色的离子缩合物被苯萃取,使有色萃合物的测定灵敏度大为提高,方法的表观摩尔吸光系数为ε＝２．７６ ×１０５·Ｌ·ｍｏｌ－１·ｃｍ－１。回归方程：ｙ＝－０．０３０１＋０．０８０８ｘ;相关系数ｒ＝０．９９８;萃取率为９７％;标准偏差为ＳＤ＝ ３．１× １０－５;用于电吸尘铜烟灰中微量铼的测定,结果令人满意。２实验部分２．１主要仪器和试剂 ７２２型光栅分光光度计（上海第…     

铜烟灰中铼的测定

研究了在ｐＨ＝ ２．４ 的磷酸氢二钠－ 柠檬酸缓冲体系中， 用苯萃取高铼酸根与乙基紫生成蓝绿色的离子缔合物。 试剂和缔合物的最大吸收均在６１１ ｎｍ 处。 表观摩尔吸光系数 ε＝ ２ ．７６ ×１０５ Ｌ·ｍｏｌ－ １ ·ｃｍ － １ ， 铼含量在０ ～１ ．２ ｍｇ／Ｌ 范围内服从比尔定律。 方法用于电吸尘铜烟灰中铼的测定， 结果令人满意。     

电感耦合等离子体发射光谱法测定富铼渣中的铼

建立了电感耦合等离子体发射光谱法测定富铼渣中铼含量的方法。对样品的酸密闭消解、碱熔解和测定铼的条件进行了研究。结果表明：于10%盐酸介质、227.525 nm分析线,铼测定浓度在0.20～50.00 μg/ mL线性良好;两种样品分解方法测得铼结果吻合,用于富铼渣样品中1.85%～3.66%铼含量的测定,检出限、相对标准偏差(RSD,n=22)和回收率分别为酸密闭消解法6.46×10-10 μg/mL、0.689%～1.065%和99.95%～100.06%,碱熔解法6.49×10-10 μg/mL、0.691%～1.059%和99.96%～100.31%。     

电感耦合等离子体发射光谱法(ICP-AES)测定富铼渣中的铼

建立了电感耦合等离子体发射光谱法测定富铼渣中铼含量的方法。对样品的酸密闭消解、碱熔解和测定铼的条件进行了研究。结果表明：于盐酸(10%)介质、227.525 nm分析线处,铼测定浓度在0.20～50.00 μg/mL线性良好;两种样品分解方法测得铼结果吻合,用于富铼渣样品中1.85%～3.66%铼含量的测定,检出限、相对标准偏差(RSD,n=22)和加标回收率分别为酸密闭消解法6.46×10-10 μg/mL、0.69%～1.1%和99.95%～100.06%,碱熔解法6.49×10-10 μg/mL、0.69%～1.1%和99.96%～100.31%。     

二阶导数红外分光光度法同时定量分析有机酸,酯

本选用有机酸、酯的－（Ｃ＝Ｏ）－红外特征峰作为分析峰，运用二阶导数法消除两分析峰之间的相互干扰，建立了用二阶导数红外分光光度法同时分析同一体系中有机酸、酯含量的新方法，其表观摩尔吸光系数分别为４．４４×１０＾４Ｌ·ｍｏｌ＾－１·ｃｍ＾－１，３．９４×１０＾４Ｌ·ｍｏｌ＾－１·ｃｍ＾－１，体系中的其它物质均不干扰测定。此方法操作简单、重现性好、选择性好，实样测定获得了满意的结果。     

影响铂铼催化剂性能的某些因素

铂铼重整催化剂虽然早已工业化,但其性能仍在不断改进,其作用机理也仍在不断深入的探讨中。一般认为,铂铼催化剂的性能与其制备条件密切相关。认为,高温焙烧可提高催化剂的活性和稳定性。而Charcosset等的看法是,焙烧削弱了铂铼的相互作用,对还原过程中生成铂铼合金不利。近来还有不少文献报导了担体的浸渍方式对铂铼催化剂的影响。在铂铼中加入第三金属以及研究予硫化的报导也很多。     

胶束增敏荧光光度法测定布美他尼

提出了在表面活性剂ＴｒｉｔｏｎＸ－１００存在下,高灵敏度胶束增敏测定布美他尼的荧光光度新方法。方法灵敏度高,检出限为２．０·１０＾－８ｍｏｌ·Ｌ＾－１,线性范围宽,为２．２·１０＾－８￣１．５·１０＾－５ｍｏｌ·Ｌ＾－１回收率为９９．８％,本对测定条件作了详细研究,本方法已应用于样品中布美他尼的测定。     

含有吸附络合物溶液的倒数示波计时电位法的应用

Ｐｂ（Ⅱ）在０．２％乙二胺－５×１０＾－３ｍｏｌ·Ｌ＾－１ＨＯｘ－０．３ｍｏｌ·Ｌ＾－１ＫＯＨ溶液中，有良好的全数示波图，其峰电位Ｅｐ＝－１．０５（ｖｓ．ＳＣＥ），峰高与Ｐｂ＾２＋溶度在４．０×１０＾－７～２．０×１０＾－５ｍｏｌ·Ｌ＾－１内成正比，检测下限可达２．０×１０＾－７ｍｏｌ·Ｌ＾－１。本实验采用倒数示波计时电位法对铝合金“Ａ”中铅进行了测定，并直接通过示波图，对络合物的吸附属于性进行了     

单扫示波极谱法测定溴离子

在０．４５ｍｏｌ·Ｌ＾－１硝酸底液中,用单扫示波极谱仪,阳极化扫描,导数档,溴离子于＋０．１４Ｖ产生一尖锐、灵敏的极谱波。检出限为２μｇ·ｍｌ＾－１,工作曲线由２．４￣１０μｇ·ｍｌ＾－１及１０￣２０μｇ·ｍｌ＾－１两条不同斜率的直线组成,前者灵敏度是近者的两倍。常见阳离子Ｆ＾－、ＳＯ４＾２－、ＢｒＯ＾－３、ＮＯ３＾－不干扰Ｂｂ＾－的测定,用此法测定长江水、溴酸钾中的微量溴离子,回收率为１０７％和     

钯(Ⅱ)与对碘偶氮氯膦显色反应的研究

钯（Ⅱ）与对碘偶氮氯膦在硝酸介质中形成组成比为１：２的蓝色配合物,其最大吸收波长位于６４０ｎｍ,表观摩尔吸光系数ε＝３．３×１０＾４Ｌ·ｍｏｌ＾－１·ｃｍ＾－１,钯的质量浓度在０．０￣１．０ｍｇ／Ｌ范围内符合比尔定律。应用于废钯催化剂回收液中铯含量的测定,结果满意。     

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.