活性炭富集示波极谱法测定水中痕量钒

本文研究了钒在活性炭上的吸附行为和解吸附条件，建立了ｐＨ３－４条件下吸附，氢氧化钠溶液洗脱，示波极谱法测定水中痕量钒的方法，本法富集倍数为１００，对水样的最小检出浓度为０．０５μｇ／Ｌ加标回收率为８７．４％－１００．３％，７份平行样品测定的相对标准偏差为３。５％－１２．８％。     

测定玻璃体和房水中维拉帕米含量的高效液相色谱法

研究了用ＨＰＬＣ 测定兔眼玻璃体和房水中维拉帕米含量的方法。用丙咪嗪为内标， 采用Ｓｐｈｅｒｉｃａｌ Ｃ１８色谱柱分离， 以甲醇－ ０ ．０４ ｍｏｌ／Ｌ 醋酸铵－ 乙腈－ 二乙胺（ 体积比１ ∶１ ∶０ ．５ ∶０ ．０２） 为流动相， 检测波长为２７８ｎｍ 。样品用正己烷－ 异丁醇提取后进样， 分析速度快。 样品及内标的保留时间分别为４ ．６３ ｍｉｎ 及９ ．２３ ｍｉｎ ； 线性范围为２ ．５ ～１００ ｍｇ／Ｌ， 相关系数ｒ 为０ ．９９９ ７ 。方法的回收率为１００ ．３ ％ （ ｎ ＝ ５） ，ＲＳＤ 为３ ．６３％ ， 日内ＲＳＤ 为０ ．５ ％ ～３ ．６１ ％ ， 日间ＲＳＤ 为３ ．７５ ％ ～４ ．８０ ％ ， 最低检测质量浓度为０．２５ ｍｇ／ Ｌ。 应用该法测定了创伤家兔玻璃体和房水中维拉帕米浓度的变化。     

用锌—镉测定天然水中硝酸盐的一种新方法

提出了用锌－镉测定天然水中硝酸盐的一种新方法即通过加入ＮＨ３．Ｈ２Ｏ－ＮＨ４Ｃｌ缓冲液，使硝酸盐的还原率由２０％提高到８７％。方法相对标准偏差为２．１％，检出限为０．１０μｍｏｌ／Ｌ，回收率在９５％－１０２％之间；与镉－铜法相比，两种方法的相对偏差小于８．２％。     

对氨基二乙基苯胺全差示光度法测定微量铬

详细实验了铬（Ⅵ）与对氨基二乙基苯胺氧化显色反应的条件。实验结果表明：铬（Ⅵ）与对氨基二乙基苯胺反应形成的红色产物在５５４ｎｍ处有最大吸收。表观摩尔吸收系数为３．３×１０＾４Ｌｍｏｌ＾－１．ｃｍ＾－１线性范围为０－１．６ｍｇ／Ｌ。实验了采用全差示光度法测定水中铬的条件，用于某湖水中４．０７μｇ／Ｌ的铬测定时，相对标准偏差为３．４％。测定结果与二苯胺基脲法的测定结果相比令人满意。     

氢化物发生—冷阱捕获—色谱分离—原子吸收法测定天然水中坤的形态

研究建立了氢化物发生－冷阱捕获－色谱分离－原子吸收方法测定天然水中四种主要砷形态，测试系统自行组装，色谱柱填料采用ＣｈｒｏｍｏｓｏｒｂＧＡＷ－ＤＭＣＳ（粒径０．３～０．４５ｍｍ），其上涂布３％ＯＶ－１０１。方法的检出限以砷计分别为：Ａｓ（Ｖ）０．５１ｎｇ，Ａｓ（Ⅲ）０．４３ｎｇ，ＭＭＡ０．３８ｎｇ，ＤＭＡ０．６７ｎｇ；１２ｎｇ砷标准偏差为Ａｓ（Ⅴ）４．２１％，Ａｓ（Ⅱ）３．５６％，ＭＭＡ３．２３％     

火焰原子吸收法测定植物样品中硼与碘

将ＢＯ＾３－３转化为ＢＦ＾－４，ＩＯ＾－３转化为Ｉ＾－以Ｃｄ（ｐｈｅｎ）＾２＋３络合和硝基苯萃取，用火焰原子吸收法间接测定与碘，其特征浓度达０．０１６μｇ／ｍＬ１％Ａ和０．０２８μｇ／ｍＬ１％Ａ，在稻米等样品中作加标回收，硼回收率为９２．８－１０２．４％，碘为９７．２－１０６．７％。     

用色谱—质谱和质量以谱研究苯甲酸钐热分解反应

为合成某些芳香族有机化合物提供一种新途径，用色谱－质谱联用技术和质量色谱法研究了苯甲酸钐的热分解反应产物。其热分解产物溶入丙酮后有大量９，１０－蒽醌析出，其丙酮溶液中还含有１，２－二苯甲酰基苯（２５．６％）、苯甲酸（１８．７％）、二苯酮（１４．４％）、９－勿酮（８．２％）、９－苯甲勿（４．９％）、取苯（３．６％）、二苯甲烷（２．３％）、３－甲酰苯基联苯（２．１％）、二苯基乙二酮（１．９％）、４－甲     

高效液相色谱法分析精对苯二甲酸中的微量杂质

应用高效液相色谱法,采用阴离子交换键合固定相,以磷酸盐缓冲溶液为流动相,ＵＶ２５４ｎｍ检测,外标法定量,同时测定了精对苯二甲酸（ＰＴＡ）中的主要杂质４－羧基苯甲醛（４－ＣＢＡ）和对甲基苯甲酸（ｐ－ＴＯＬ）的含量,４－ＣＢＡ和ｐ－ＴＯＬ的回收率分别为９８．３％～１０５．０％和９６．０％～１０３．８％,变异系数分别小于１．７％和３．３％。方法快速、准确,用于实际样品分析可得到满意的结果。     

偏最小二乘催化极谱法同时测定铂,钯,铑

应用Ｍ２７３Ａ电化学系统中的线性扫描技术，确定了０．７５ｍｏｌ／ＬＨ２ＳＯ４－１．５％ＮＨ４Ｃｌ－２．８ｍｍｏｌ／Ｌ（ＣＨ２）６Ｎ４－０．００２５％Ｎ２Ｈ４．Ｈ２ＳＯ４为偏最小二乘极谱法同时测定Ｐｔ、Ｐｄ、Ｒｈ的最佳极谱体系。Ｐｔ、Ｐｄ、Ｒｈ的线性范围为３．２ｍｇ／Ｌ、０－１５．０ｍｇ／Ｌ和０－１．０ｍｇ／Ｌ。模拟样品及实际样品的回收率在９０．３－１０７．７％之间。     

荧光法测定环境水中微量久效磷

采用荧光分光光度法测定了环境水中微量久效磷的含量。在０．２５％的吲哚丙酮溶液与０．２５％的过硼酸钠溶液的混合液中，体系温度为５℃时，λｅｘ／λｅｍ＝４２０ｎｍ／５００ｎｍ，检测限为４．０μｇ／Ｌ，线性范围为０－３．２μｇ／ｍＬ，回收率为９８％－１０４％，结果令人满意。     

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%.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

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.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.