聚酰胺富集吸光光度法测定金

ＰＶＣ－聚己内酰胺作为金的富集利，从稀盐酸或王水介中富集微量金，具有吸附速度快，容易洗脱，吸收容量大等优点，在选择的色层条件下，除贵金属和铊外，普通离子不被吸附，可广泛用于分离富集各类矿物中微量金。     

纤维状负载双硫腙聚酰胺树脂对铅的吸附性能

将市售粉粒状聚酰胺树脂在低温下改性后再与二苯基硫卡巴腙(双硫腙)进行负载反应,制成纤维状负载双硫腙聚酰胺树脂。研究了柱层析操作条件下,该树脂对铅的选择性吸附分离方法。实验表明,在pH3～7的HCl介质中,改性负载聚酰胺树脂对铅的吸附性能很好,饱和吸附容量为9．56mg/g,树脂上的铅可用5％的中性EDTA溶液进行洗脱。结合原子吸收分光光度法测定,方法可用于环境样品中微量铅的富集分离和测定。     

2-(2-噻唑偶氮)-5-[(N,N-二羧基甲基)氨基]苯甲酸浸渍树脂吸附金的特性及应用

用1300－Ⅱ型吸附树脂吸附噻唑偶氮类试剂制取浸渍树脂。研究了树脂对试剂和对金的吸附率及其与溶液pH值的关系，求得浸渍树脂吸附金的平衡速率和吸附容量，并在条件试验基础上拟订了柱操作分离富集微量金的方法，获得了满意的结果。     

2—2（—噻唑偶氮）5—[（N,N—二羧基甲基）氨基]苯甲酸浸渍树脂吸附金的…

用１３００－Ⅱ型吸附树脂吸附噻唑偶氮类试剂取浸渍树脂。研究了树对试剂和对金的吸附率及其与溶液ＰＨ值的关系，求得浸渍树脂吸附金的平衡速率和吸附容量，并在条件试验基础拟订了柱操作分离富集微量金的方法，获得了满意的结果。     

改性聚酰胺负载丁二肟吸附富集原子吸收光谱法测定水中镍

研究了负载丁二肟的改性聚酰胺对镍的吸附和富集行为,确立了负载丁二肟的改性聚酰胺对镍的吸附洗脱条件,建立了负载丁二肟改性聚酰胺对镍富集、分离原子吸收光谱测定的分析方法。结果表明,在pH10的碱性条件下,负载丁二肟的改性聚酰胺对镍有较好的吸附行为,其吸附容量为0．5mg／g;用5mL0．6mol／L的硝酸作为洗脱液,洗脱率可达到100％;负载丁二肟的改性聚酰胺可重复使用三次,吸附率仍可高达到95％以上;方法的富集倍率为80倍;通过对地表水的测定结果令人满意。     

泡沫塑料富集原子吸收光谱法测定铅锌矿中的金量

根据铅锌矿的性质特点和含量范围,对微量金的富集采用二次富集,不洗脱,直接灰化后溶解定容测定,进行了一次、二次吸附回收率试验及对比试验.     

乙二胺改性聚氯乙烯大孔螯合树脂富集分离微量金, 铂, 钯, 铱的性能和机理研究

本文利用ICP化学光谱法对自合成的聚乙烯乙二胺大孔螯合树脂富集分离微量金、铂、钯、铱进行了研究。讨论了螯合树脂对各微量元素的富集性能、吸附速率和富集机理,并进行了样品的分析,获得了较满意的结果。     

乙二胺改性聚氯乙烯大孔螯合树脂富集分离微量金, 铂, 钯, 铱的性能和机理研究

本文利用ICP化学光谱法对自合成的聚乙烯乙二胺大孔螯合树脂富集分离微量金, 铂, 钯, 铱进行了研究, 讨论了螯合树脂对各微量元素的富集性能、吸附速率和富集机理, 并进行了样品的分析, 获得了较满意的结果。     

半胱氨棉吸附—原子吸收法测定地质样品中的微量金

本文介绍用半胱氨棉在5MHCl—pH5介质中富集地质样品中的微量金,常见的18种共存离子用柠檬酸能消除对吸附金的干扰。对吸附速度和半胱氨棉用量的研究,得到操作简便、快速易于掌握的方法。     

VS-Ⅱ型阴离子交换纤维分离富集原子吸收法测定土壤样品中微量金

1 引言 本文采用VS-Ⅱ型阴离子交换纤维分离富集微量金,研究了金在盐酸介质中形成氯络阴离子,与阴离子纤维进行交换吸附的性能。采用酸性硫脲定量洗脱,火焰原子吸收法测定样品中的微量金。本法具有快速,准确,价廉的优点,因而具有实际应用和推广价值。     

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.