UV-Vis-草酸铁络合物-H2O2体系产生羟自由基的Fe(phen)23+光度法测定

UV－Vis－草酸铁络合物－H2O2法是一种新的高级氧化工艺，该工艺产生的羟自由基·OH具有极强的氧化能力，可与水中大多数有机物迅速反应而使其降解；用Fe(phen)23+光度法研究了该体系中羟自由基·OH产生的规律，·OH可将Fe(phen)23+(Fe2＋－菲咯啉络合物)氧化成Fe(phen)23+(Fe3＋－菲咯啉络合物),通过测定Fe(phen)23+在508nm处吸光度的变化可间接求出·OH的生成量；结果表明，在pH=4.0,=1∶5∶10（化学计量数）时，·OH的生成量最大;该分析方法具有简单、快速的优点。     

镀铜锌粒还原-流动注射-化学发光同时测定两种价态的铁

建立了镀铜的锌粒在线还原微柱，还原Fe3+成Fe2+，鲁米诺中加EDTA增强鲁米诺-溶解氧-铁（Ⅱ）系统的发光强度，同时测两种价态的铁，提高灵敏度160倍，线性范围均为1×10－9～1×10－5mol／L．RSD≤6．0％，Fe3+和Fe2+的检出限分别为3．5×10－10和2．7×10-10mol／L。每小时可测定60个试样，测定结果与标准方法无显著差异。     

高铁-邻菲啰啉－溴甲酚蓝显色体系－离心光度法测定铁

１引言铁对人体的生理功能有着十分重要意义，是人体生命活动中极为重要的微量元素。健康者的血清铁为１１－１６μｍｏｌ／Ｌ。人体缺铁或铁摄入过量、积累都对人体健康有害。现代医学研究表明，血清铁与恶性肿瘤有其相关性。铁临床检验多采用二元络合物显色体系如硫氰酸盐法、邻菲啰啉（ｐｈｅｎ）法和α，α－联吡啶法等，这些方法不仅灵敏度低（ε多为ｌ０４Ｌ·ｍｏｌ－１·ｃｍ－１），且多需将Ｆｅ（Ⅲ）还原为Ｆｅ（Ⅱ）再行显色测定。本文研究了Ｆｅ（Ⅲ）－ｐｈｅｎ－溴甲酚蓝三元络合物显色体系－离心光度法直接测定高铁，其灵敏…     

硫氰酸根-邻二氮菲-乳化剂OP分光光度法测定油品中的铁

以Fe3+-SCN--Phen-OP为显色体系,测定油品中的铁,详细考查了测定条件,建立了测定油品中微量铁的新方法.络合物最大吸收峰位于520 nm,表观摩尔吸收系数为1.87×104 L·mol-1·cm-1,铁质量浓度在0～2.4 μg/mL内服从比尔定律.油样分析结果的相对标准偏差2.1%,加标回收率96.0%～102.0%.方法适合于油品中微量铁的测定.     

聚(苯乙烯-丙烯酸)载体铁邻菲啰啉(5-硝基邻菲啰啉)配合物的合成及其对丁二烯聚合的催化活性

合成了不同邻菲啰啉(phen)含量的聚(苯乙烯-丙烯酸)载体铁邻菲啰啉配合物(SAAC·Fe·phen)和不同5-硝基邻菲啰啉(Nphen)含量的聚(苯乙烯-丙烯酸)载体铁5-硝基邻菲啰啉配合物(SAAC·Fe·Nphen)。元素分析和红外结果证明SAAC·Fe·phen具有下面的结构:SAAC·Fe·phen-(i-Bu)_3Al二元体系的催化效率是SAAC·Fe-phen-(i-Bu)_3Al三元体系的2倍,是小分子铁的400倍。在SAAC·Fe·phen和SAAC·Fe·Nphen体系中,当phen(或N pnen)/Fe的摩尔比为0.7左右时催化活性最高。催化活性随着Al/Fe摩尔比的增大而升高,但当Al/Fe摩尔比大于70以上活性趋于恒定,和小分子铁催化荆相比这种高分子铁催化剂可以提高聚合温度。     

纳米-微米铁修饰的维氏体氨合成催化剂

我们以商业预还原的维氏体(Fe1-xO)氨合成催化剂为载体,采用Fe(NO)3 ·9H2O和H2C2O4·2H2O进行原位室温固相反应制备纳米铁或微米铁修饰的铁基氨合成催化剂,并通过XRD、SEM、TG-DTG、H2-TPR等进行了表征.结果表明:Fe(NO)3·9H2O和H2C2O4·2H2O室温固相反应完全生成产物Fe2(C2O4)3·5H2O,且产物分散于载体维氏体催化剂表面.通过纳米铁-微米铁的修饰,催化剂的氨合成活性有很大提高且稳定性好.催化剂活性随着Fe负载量的增加先增加后降低,负载量5％时催化活性最好,反应器出口氨浓由450℃(12.4％)、425℃(11.0％)、400℃(9.4％)分别提升至450℃(15.6％)、425℃(14.8％)、400℃(13％).通过一步简单的修饰,维氏体催化剂的氨合成活性提高约25％ ～38％.由于焙烧和还原,生成的Fe1xO或铁粒子与铁催化剂表面发生强相互作用,因此,反应过程中纳米铁或微米铁粒子能稳定存在,催化剂有较高的稳定性.     

2-(4-氯-2-膦酸基苯偶氮)-7-(2,6-二溴-4-氯苯偶氮)-1,8-二羟基3,6-萘二磺酸与铋的显色反应及应用

１ 引 言 ＤＢＣ－偶氮氯膦全称为：２－（４－氯－２－膦酸基苯偶氮）－７－（２，６－二溴－４－氯苯偶氮）－１，８－二羟基３，６－萘Ｈ磺酸，简写为ＤＢＣ－ＣＰＡ。它已用于稀土、钡、锶、钙和钐的测定。作者在研究了该试剂与铁显色反应的基础上，又研究了与铋的显色反应，发现在１．２ｍｏＬ／Ｌ　ＨＣｌＯ４的介质中，于少量乙醇存在下，试剂与铋生成２：１的络合物，络合物稳定性好，灵敏度高，其表观摩尔吸光系数 １．０８× １０５ Ｌ·ｍｏｌ－１·ｃｍ－１，常见离子：银、镁、镉、钴、镍、铜、锰、铝、锌、铁、铬、硅等允许共…     

痕量铁的催化分光光度法研究

研究了在S2SO4介质中，以1，10－二氮菲为活化剂，铁（Ⅲ）催化过氧化氢氧化甲基橙的褪色反应的动力学条件。建立了测定痕量铁（Ⅲ）的动力学分析法。方法的灵敏度1．78×10－8g·L－1，线性范围0～1．2×10－5g·L-1。用于测定饮用水和湖水中的痕量钱，相对标准差在5％以内，平均回收率97％～106％。     

2-〔2′-(6-溴-苯并噻唑)-偶氮〕-1,8-二羟基萘-3,6-二磺酸的合成及其与钛的显色反应

本文合成了一种新的革并座隆类显色试剂—2－［2′－（6－溴－苯并噻唑）－偶氮］－1，8－二羟基萘－3，6－二磺酸（简称Br－BTCA），并研究了其与钛的显色反应。在CTMAB存在下，钛与试剂形成稳定的络合物，其ε616=1．15×105L·mol－1·cm-1，组成为Ti（Ⅳ）：R：=1：2：钛浓度在0～0．5mg／L范围内符合比尔定律，该方法灵敏度高，选择性好，并用于铝合金及硅铁试样中微量钛的测定     

7-(对甲酰基苯偶氮)-8-羟基喹啉-5-磺酸的合成及其双波长分光光度法测定镓

7－（对甲酰基苯偶氮）－8－羟基喹啉－5－磺酸是一新显色剂。该试剂在微碱性介质中（pH＝7．5）与镓形成黄色络合物。络合物λmax＝392nm，摩尔吸光系数ε392＝2．24×104L·mol-1·cm-1。同时在500nm呈现负峰，用双峰观波长法测定镓ε392～500＝6．89×104L·mol-1·cm－1，灵敏度是单波长法的三倍多．线性范围0～2．0×10－5mol／L。用拟定的方法测定了掺硅的GaAS材料及岩石中的镓，加入回收率为106％～110％；方法的相对标准偏差小于1．6％。     

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%.     

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.     

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.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Construction of polyheterocyclic spirotetrahydrothiophene derivatives via sulfa-Michael/aldol cascade reaction

A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).     

Suzuki-Miyaura reactions of the soluble guanylate cyclase inhibitor NS2028: a non-product specific route to C-8 substituted analogues

Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO₄ oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.