硅胶-TBP反相萃取层析分离测定水系沉积物及岩矿中微量钼和锡

本文研究了钼与PV-CTMAB的显色反应,结果表明该体系灵敏度虽高,选择性却很差。为此,本文采用硅胶-TBP反相萃取层析法,使Mo、Sn与Ti、W、Ge、Cu、Pb、Zn、Ni、Mn、Fe等分离,提高了方法的选择性.并应用于含上述诸多离子的复杂试样——水系沉积物、岩矿中微量Mo、Sn的测定,取得满意的结果。     

钍、钼和钨的反相分配色谱分离和测定

用反相分配层析法,可以有效地分离Th、Mo和W,在7 mol/L HCl介质中,Th不为三辛胺-Kel-F柱吸附。此时Mo和W保留在柱上,改用4 mol/L HCl作流动相,则W被迅速洗脱,而Mo仍牢固地保留在柱上。最后用0.1 mol/LHCl解吸钼。1 cm×11 cm的层析柱可使50 mgTh与5~50μg的Mo和W定量分离。Th的回收率为100±0.2%,Mo和W的最大相对误差为2%。在4 mol/LHCl介质中,亦可使1~10 mg的Mo(或W)与5~10μg的W和Mo分离,其中μg量组份的相对误差≤2%。     

三七生长初期不同部位微量元素的含量测定

采用电感耦合等离子体发射光谱法(ICP-AES),对文山地区GAP种植及农户常规种植的生长初期三七不同部位中的微量元素Mg、P、Ca、Mn、Na、Fe、Co、Cu、Zn、Mo、Cr、Ni、Ge、Se等14种元素进行了测定分析。结果表明,三七的根、茎、叶中含有丰富的人体必需Mg、P、Ca、Mn、Na、Fe、Co、Cu、Zn、Mo、Ge、Se等有益元素,且P、Ca、Mg、Fe含量较高,Na、Mn、Co、Zn次之,Co、Mo、Cr、Ni、Ge、Se含量均较低。为三七GAP栽培标准和特征制订、三七道地药材的化学特征——化学指纹图谱的建立及研究提供理论依据。     

萃淋树脂微色谱柱分离富集-苯基荧光酮光度法测定中草药中痕量锗和钼

研究了在微色谱柱中以CL-TBP萃淋树脂为固定相,运用零空床体积洗脱技术,反相萃取分离痕量Ge、Mo。洗脱体积仅1.0~1.2 mL便可实现两元素的连续分离。洗脱液用苯基荧光酮-溴化十六烷基三甲基溴化铵(PF-CTMAB)光度法进行测定。该树脂对Ge、Mo的动态吸附容量分别为34.8 mg/g和67.4 mg/g,加标回收率分别为91.4%~98.6%和96.6%~101.3%,相对标准偏差(RSD)分别在2.53%~5.74%和1.91%~4.12%之间。方法用于中草药中痕量Ge、Mo的测定,结果满意。     

电感耦合等离子体质谱法测定人促红素注射剂中13种杂质元素

建立了电感耦合等离子体质谱法测定人促红素注射剂中Cd、Hg、Pb、As、Co、V、Ni、Sb、Mo、Cu、Cr、Al、Fe共13种杂质元素含量。以Sc、In、Ge为内标,采用ICP-MS法测定,等离子体射频功率为1 549 W,载气流量为1.12L/min。Al、Fe质量浓度在0～50 ng/mL范围内、其余11种元素质量浓度在0～10 ng/mL范围内线性关系良好,相关系数均不小于0.999,样品加标平均回收率为81.5%～118.0%,测定结果的相对标准偏差为1.10%～2.82%(n=6),各元素检出限为0.001 5～1.148 8 ng/g。不同厂家的人促红素注射剂中13种杂质元素的含量均符合ICH规定。该方法准确性好,灵敏度高,可同时测定多种元素,适用于人促红素注射剂中杂质元素的质量控制。     

硫酸铵-溴化钾铵-正丙醇体系萃取分离和富集锗的研究

研究了硫酸铵-溴化钾铵-正丙醇体系萃取分离和富集锗的行为及与一些金属离子分离的条件.硫酸铵能使正丙醇的水溶液分成两相,在分相过程中,Ge4+与KBr生成(GeBr62-),并与质子化正丙醇(C3H7OH2+)形成缔合物[GeBr62-][C3H7OH2+]2,此缔合物能被正丙醇相完全萃取.当正丙醇、KBr和硫酸铵的浓度分别为30％(V/V)、7.0×10-3mol/L、0.20g/mL时,(GeBr62-)的萃取率达到97.7％以上,而Ni2,Pb2,Cr3+,Co2,Fe3+,Al3+,Mg2+,Ag+,Bi3+,CH2,W(Ⅵ)和V(Ⅴ)基本不被萃取,实现了Ge4+与上述金属离子的分离.     

中国化学物相分析研究的新成就(下)

分两部分介绍了我国化学物相分析近十余年来研究的新成就。第二部分（下）则对物料物质组成的相态与元素(Fe,I,Mn,Mo,Na,P,Re,S,Sb,Se,Si,Sn,Sr,Ti,U和V等)价态分析、赋存状态分析以及非金属矿物相分析等的研究现状,分别予以简要评述。同时对其存在的问题和进一步研究的方向也进行了讨论。引用文献114篇。     

硫氰化铵-溴化十六烷基吡啶体系浮选分离和富集锗

研究了硫氰化铵-溴化十六烷基吡啶(CPB)体系浮选分离锗的行为及与一些金属离子分离的条件。结果表明,在水溶液中,Ge(Ⅳ)与硫氰化铵和溴化十六烷基吡啶形成不溶于水的三元缔合物[Ge(SCN)62-][CPB+]2,此三元缔合物沉淀浮于水相上层形成界面清晰的液-固两相。当溶液中溴化十六烷基吡啶和硫氰化铵的浓度分别为3.0×10-3mol/L和1.5×10-2mol/L时,Ge(Ⅳ)可与Ga(Ⅲ)、Ni(Ⅱ)、Cd(Ⅱ)、Mg(Ⅱ)、Mn(Ⅱ)、Fe(Ⅱ)、Al(Ⅲ)、Cr(Ⅲ)和V(Ⅴ)离子定量分离,Ge(Ⅳ)的浮选率达到98.3%以上。对合成水样中Ge(Ⅳ)的分离和测定,结果满意。该方法在微量锗的分离和富集分析中有一定的实用价值。     

过氧化氢在液固相绿色氧化反应中的应用

介绍了由各种金属Ti, Mn, Cu, Al, Os, Ru, W, V, Fe, Mo, Re制备的固相催化剂体系,以过氧化氢为氧化剂,实现了温和条件下绿色氧化反应.     

抗坏血酸滴定铁的探讨

在测铁时,经常要分离Cu、Au、Ag、As、Sb、Mo、W等元素,操作烦琐,还往往带来误差。用抗坏血酸作为铁的滴定剂,不分离铜可直接测定,但其它元素对测定有无影响,则未见报道。本文对抗坏血酸测定铁进行了实验研究,结果表明,上述各元素对测铁均无影响,因此本法优于重铬酸钾、硫酸铈、     

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.