催化动力学光度法测定药物和饮用水中痕量铁的研究

本文利用Ｆｅ＾３＋＋对Ｈ２Ｏ２氧化二苯胺碘酸的反应具有催化作用，且在一定条件下显色反应的速度与催化剂Ｆｅ＾３＋的含量成正比的原理，建立了一种痕量铁的分析方法。本文方法的线性范围为０．００８－０．０６４ｍｇ＝Ｌ，相对标准偏差小于５．０％，标准加入回收率为１０１％－１０３％，检出限为０．００６７３ｍｇ／Ｌ。     

单柱离子色谱法同时测定磷酸中痕量钠（Ⅰ）和铁（Ⅲ）

以酒石酸－乙二胺为淋洗液的单柱离子色谱法同时测定磷酸中痕量钠（Ⅰ）和铁（Ⅲ）。淋洗液最佳浓度为４．０ｍｍｏｌ．Ｌ￣（－１）、酒石酸／１．０ｍ　ｍｏｌ·Ｌ￣（－１）乙二胺。最低检测限为Ｎａ￣＋０．０５μｇ／ｍＬ、　Ｆｅ３＋　０．４５μｇ／ｍＬ。电导检测灵敏度为２．０μｇ／ｃｍ。线性范围Ｎａ￣＋、Ｆｅ３＋０．２～１．５×１０３μｇ／ｍＬ、２．５～１．０×１０３μｇ／ｍＬ。相对平均偏差Ｎａ￣＋为２．０３％、Ｆｅ３＋为０．８３％。平均回收率Ｎａ￣＋为９８．２６％、Ｆｅ３＋为９７．６２％。本法简便、快速、准确、选择性好。     

火焰原子吸收光谱法间接测定非金属材料中氯

报道了火焰原子吸收光谱法（ＦＡＡＳ）间接测定非金属材料中氯的方法，采用ＡｇＣｌ沉淀，测定剩余Ａｇ~＋间接求出氯含量。方法的特征浓度为０．０１４ｍｇ／Ｌ（１％吸收），检出限为０．０３２ｍｇ／Ｌ（３），测定下限为０．１１ｍｇ／Ｌ，相对标准偏差（ＲＳＤ）为１．５％～１０％，样品加标准回收率在９１．４％－１０５％之间。     

反相色谱法分离和间接光度法测定无机阴离子

在化学键合固定相ＯＤＳ柱上,用Ｆｅ（Ｐｈｅｎ）_３~（２＋）作流动相添加剂分离并用间接光度法检测无机阴离子。探讨了主要因素（如流动相中Ｆｅ（Ｐｈｅｎ）_３~（２＋）浓度、有机溶剂浓度、ｐＨ值和离子强度等）对阴离子保留和检测灵敏度的影响。Ｃｌ~－,Ｂｒ~－,ＮＯ_３~－和Ｉ~－具有良好的分离度;间接光度检测波长为Ｆｅ（Ｐｈｅｎ）_３~（２＋）的最大吸收波长５１０ｎｍ。测定这４个离子的校正曲线的线性范围为１～１６０ｍｇ／Ｌ（Ｃｌ~－,Ｂｒ~－,ＮＯ_３~－）和２～３２０ｍｇ／Ｌ（Ｉ~－）;相关系数均达０．９９６。     

铁的单点络合滴定法研究

本研究了Ｆｅ＾３＋的单点络合滴定法，导出了定量关系式，比较了以铂电极为指示电极和以ＰＶＣ膜四氯络铁（Ⅲ）阴离子电极为指示电极时电位测量的稳定性及所得的分析结果。在Ｆｅ＾３＋浓度为１．０００×１０＾－３ｍｏｌ／Ｌ时，１８次实验的平均值为１．０２×１０＾－４ｍｏｌ／Ｌ，相对偏差小于１．７％；Ｆｅ＾３＋在５．０×１０＾３ｍｏｌ／Ｌ以上时，相对偏差小于０．１％；其浓度小于１０＾－３ｍｏｌ／Ｌ而大于５×１     

流动注射分析光度法同时测定镍和铁

建立了流动注射（ＦＩＡ）光度法同时测定镍和铁的新方法，以乙酸－乙酸钠缓冲溶液（ＰＨ４．５０）作载液，溴化十六烷基三甲胺作增溶剂，记录５６０ｎｍ处Ｎｉ（Ⅱ）－Ｂｒ－ＰＡＤＡＰ与Ｆｅ（Ⅱ）－Ｂｒ－ＰＡＤＡＰ的峰值吸收之和７４６ｎｍ处Ｆｅ（Ⅱ）－Ｂｒ－ＰＡＤＡＰ的吸不度测定了钠基合金中的镍和铁。两咱离子的定量线性范围分别为０．１０－１．２０ｍｇ／ｌＬ和０．２０－１．６０ｍｇ／Ｌ，检出限为０．０２ｍｇ／Ｌ     

光化学反应在流动注射分析中的应用研究：Ⅲ.甲基橙光化学反应…

基于ＮＯ２＾－，ＮＯ３＾－和Ｆｅ（Ⅲ）对甲基橙光化学褪色反应的催化作用，利用自制流通式光化学反应应器，建立了流动注射光化学反应同时测定ＮＯ２＾－和ＮＯ３＾－以及测定Ｆｅ（Ⅲ）的新方法。测定ＮＯ２＾－和ＮＯ３＾－的线性范围都是０．１－３．２ｍｇ／Ｌ，每小时可测３０－４０个样品。测定Ｆｅ（Ⅲ）的线性范围为０．０６－１．２ｍｇ／Ｌ，进样频率为６０－８０次／ｈ。应用于蔬菜中ＮＯ２＾－，ＮＯ３＾－的测定和茶     

不经分离,高敏,连续光度滴定混合物中钕和铁

提出以Ｆｅ（３＋）（Ｎｄ（３＋）－ＣＡＳ－ＣＰＢ－Ｃ２Ｈ５ＯＨ作为不经分离、高敏、连续光度配合滴定混合物中Ｆｅ（３＋）和Ｎｄ（３＋）的多元胶束配合指示体系。滴定Ｆｅ（３＋）和Ｎｄ（３＋）的适宜ｐＨ分别为２．３～３．２和６．０～８．６。用ＥＤＴＡ目视滴定Ｆｅ（３＋）时，终点处由蓝紫变粉红色，对比度大（Δλ＝１３０ｎｍ）、灵敏度高（配合物摩尔吸光系数ε（６３０）＝１．１４×１０５Ｌ·ｃｍ（－１）·ｍｏｌ（－１），至少可检测０．４μｇ／ｍＬ，滴定线性范围为０～２．８μｇ／ｍＬ。线性相关系数为０．９９９４；目视滴定Ｎｄ（３＋）时，终点处由绿色变橙黄，Δλ＞１８０ｎｍ，ε（６３０）＝７．６×１０４，至少可检测１μｇ／ｍＬ，滴定线性范围０～３．７μｇ／ｍＬ，线性相关系数０．９９９４。对于铁钕硼混合物样品则不经分离在６３０ｎｍ处连续光度滴定，可更精密、高敏、准确地确定终点，变异系数１．７６％～２．８６％，标准加入回收率９６％～１０４％，且简便、快速。     

巯基葡聚糖凝胶分离富集催化光度法测定痕量铁（Ⅲ）

研究了在硫酸介质中Ｆｅ（Ⅲ）催经抗坏血酸、溴酸钾和对氯偶氮氯膦之间的褪色反应及动力学条件，建立了学光度法测定痕量Ｆｅ（Ⅲ）的新方法，其灵敏度为１．６×１０＾－９ｇ／Ｌ；建立范围为Ｆｅ（Ⅲ）０－０．１２ｍｇ／Ｌ，采用巯基葡聚糖凝胶分离干扰离子，使方法的选择性有很大的提高，已用于食品和人发中Ｆｅ（Ⅲ）的测定，结果令人满意。     

应用水解还原铁（Ⅲ）—邻二氮菲光度法测定丙酮肟

丙酮肟在酸性条件下经加热水解生成个有还原性的羟胺,并将Ｆｅ（Ⅲ）定量还原为Ｆｅ（Ⅱ）,应用Ｆｅ（Ⅱ）－邻二氮菲光度法简接测定丙酮肟。选择了水解最佳条件（加热温度、时间、介质酸度、显以剂的加入顺序等）。结果表明,测定线性范围为０￣１．２ｍｇ／Ｌ。相关系数ｒ＝０．９９９８,最低检测浓度为０．０４６ｍｇ／Ｌ,ＲＳＤ〈３．３％（ｎ＝５）。应用该法测定火力发电厂锅炉运行水中丙酮肟的含量,方法简便,灵敏度高。     

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.     

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.     

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.     

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.