钌(Ⅱ)-氯化亚锡-孔雀绿超高灵敏显色反应体系的研究-离心光度法测定钌

本文提出了一个测定钌的超高灵敏的新方法——离心光度法。摩尔吸光系数ε=1.0(±0.05)×10~7L·mol~(-1)·cm~(-1)。钌含量0.05～0.8μg/25ml呈线性关系。所拟定的方法可用于某些低品位物料中钌的分析。对其超高灵敏的显色反应机理进行了探讨。     

钌(Ⅲ)-过碘酸钾-对乙酰基偶氮羧-P体系催化分光光度法测定微量钌的研究

本文发现钌(Ⅲ)对KIO_4氧化对乙酰基偶氮羧-P褪色反应有显著的催化作用,探讨了测定微量钌的催化分光光度法的最佳条件。其表观摩尔吸光系数ε_(530)=6.16×10~5L·mol~(-1).cm~(-1),在0.1～1.5μg/10ml范围内符合比耳定律,应用于贵金属精矿中钌的含量测定,结果满意。     

钌(Ⅱ)-2-(5-溴-2-吡啶偶氮)-5-二甲氨基苯胺显色反应的研究

研究了钌 ( )与 2 - ( 5-溴 - 2 -吡啶偶氮 ) - 5-二甲氨基苯胺 (简称为 5- Br-PADMA)的显色反应。在 p H4.2～ 6.2的醋酸 -醋酸钠缓冲溶液中 ,盐酸羟胺存在并加热条件下 ,Ru( )可与试剂形成绿蓝色配合物 ,加酸酸化后 ,其最大吸收峰位于 61 9nm,表观摩尔吸光系数达 9.2 7× 1 0 4 L· mol-1· cm-1。钌 ( )浓度在 0～ 0 .80 mg/L范围内符合比尔定律。利用 EDTA作掩蔽剂 ,可允许较大量的常见金属离子存在。方法已用于样品中微量钌的测定     

5-(5-氯-2-吡啶偶氮)-2,4-二氨基甲苯分光光度法测定微量钌(Ⅲ)

研究了 5- ( 5-氯 - 2 -吡啶偶氮 ) - 2 .4-二氨基甲苯 ( 5- Cl- PADAT)与钌 ( )的显色反应。在 p H4.0～ 6.5HAc- Na Ac缓冲溶液中 ,在加热的条件下 ,5- Cl-PADAT与 Ru( )形成稳定的配合物 ,加入无机酸 ( HCl,HCl O4 ,H2 SO4 ,H3 PO4 )酸化后 ,其最大吸收波长位于 50 5nm处 ,表观摩尔吸光系数为 8.5×1 0 4 L· mol-1· cm-1,钌浓度在 0～ 6μg/ 1 0 m L范围内服从比耳定律 ,Ru( )与 5- Cl- PADAT配合物的摩尔比为 1∶ 2。以 EDTA为掩蔽剂 ,方法具有良好的选择性 ,已应用于合成样中钌的测定。     

甲苯胺蓝指示反应动力学光度法测定痕量钌

在磷酸和热水浴中 ,钌 (Ⅲ )对高碘酸钾氧化甲苯胺蓝的反应具有催化作用 ,据此建立了测定钌的新催化光度法。钌在 0～ 0 .0 5 0 μg/ 2 5ml范围内与催化反应速率有良好的线性关系 ,检出限为 5 .5 3× 10 - 5μg·ml- 1。对 0 .0 30 μg/ 2 5ml钌 (Ⅲ )测定的相对标准偏差为 2 .0 % (n =11)。该催化反应对钌 (Ⅲ )和甲苯胺蓝分别为一级反应 ,其表观活化能为 5 0 .2 6kJ·mol- 1。试验了 4 0多种共存离子的影响 ,大多数的常见离子不干扰。该方法用于岩矿和冶金产品中钌的测定 ,相对标准偏差为 2 .1%～ 2 .4 % ,标准加入回收率为 10 0 .1%～ 10 5 .4 %。     

钌(Ⅲ)-二安替比林对氯苯甲烷-高碘酸钾体系催化分光光度法测定痕量钌

在磷酸介质中及加热条件下,钌(Ⅲ)对高锰酸钾氧化二安替比林对氯苯基甲烷(DApCM)显色反应有强烈的催化作用,由此建立了测定痕量钌的方法.体系的最大吸收波长为500nm,钌的含量在0.0～4.0μg/L范围内具有线性关系,检测限为1.94×10-10g/mL,反应的表观活化能为88.20kJ/mol,反应表观速率常数为7.7×10-4/s.本方法用于矿样中痕量钌的测定得到了满意的结果.     

钌（Ⅲ）—二安替比林对氯苯甲烷—高碘酸钾体系催化分光光度法？…

在磷酸介质中及加热条件下,钌(Ⅲ)对高锰酸钾氧化二安替比林对氯苯基甲烷(DApCM)显色反应有强烈的催化作用,由此建立了测定痕量钌的方法.体系的最大吸收波长为500nm,钌的含量在0.0～4.0μg/L范围内具有线性关系,检测限为1.94×10-10g/mL,反应的表观活化能为88.20kJ/mol,反应表观速率常数为7.7×10-4/s.本方法用于矿样中痕量钌的测定得到了满意的结果.     

氢还原重量法测定三氯化钌产品中钌含量的研究与应用

建立了氢还原重量法测定三氯化钌产品大样中钌含量的新方法,研究并优化了测定条件,结合AAS法、ICP-AES法和氯化铵纯度考察了杂质元素对了分析结果的误差影响。结果表明：含钌量0.3 g～0.6 g的三氯化钌与5 g～7 g氯化铵能完全形成(NH4)2RuCl6配合物,于约100 ℃烘干水分、350 ℃分解铵盐、750 ℃氢还原为海绵钌和105 ℃干燥水气的条件下,测定3.94%、5.88%、7.32%、9.47%、10.84%和12.93%的钌含量,极差、标准偏差(S)、相对标准偏差(RSD,n=22)和重复性限(r)分别为±0.01%、0.0030%～0.0050%、0.0369%～0.0761%和0.008%～0.014%。样品加标准回收率99.96%～99.98%。本法结果准确、精密,且与YS/T 562-2009标准分析方法的吻合。     

对碘偶氮氯膦-高碘酸钾-钌(Ⅲ)的褪色反应用于痕量钌的催化分光光度法测定

在Ｈ２ＳＯ４ 介质中对碘偶氮氯膦与高碘酸钾的褪色反应只有在痕量钌（Ⅲ）的存在下才能定量进行。本文研究了该褪色反应的最佳条件及用于痕量钌的测定方法, 其检出限为０．０２ μｇ·１０ ｍ Ｌ－ １, 钌含量在０．０２～０．３０ μｇ·１０ ｍ Ｌ－ １范围内符合比尔定律。该方法用于贵金属精矿中钌含量的测定, 获得满意结果。     

聚乙烯醇存在下钌(Ⅱ)-氯化亚锡-结晶紫高灵敏显色反应体系的研究

本文研究了在聚乙烯醇存在下钌(Ⅱ)-氯化亚锡-结晶紫离子缔合体系的高灵敏显色反应。离子缔合物的最大吸收峰位于550nm处,摩尔吸光系数为1.1×10~6L.mol~(-1)cm~(-1).钌含量在0.2—2.8μg/25mL范围内符合比尔定律。对外来离子的干扰和分离进行了研究。拟定的方法可用于矿石和一些低品位贵金属物料中钉的分析。     

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.     

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.     

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.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

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.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).