痕量硝基酚的反相高效液相色谱电化学检测

本文以甲醇与０．０３ｍｏｌ／Ｌ邻苯二甲酸氢钾缓冲液为淋洗液，采用安培型电化学检测，实现了２－硝基苯酚，３－硝基苯酚，４－硝基苯酚及２，４－二硝基苯酚和２，６－０二硝基苯酚等五种酚类化合物于Ｐｅｒｋｉｎ－Ｅｌｍｅｒ Ｎｕｃｌｅｏｓｉｌ Ｃ８柱上反相高效液相色谱的分离及在Ｅ＝＋１．２Ｖ时于玻碳电极上的同时检测。     

离子色谱法测定复杂氮硫化物

建立了复杂氮硫化物的离子色谱分析方法。在选定的色谱条件下能很好地分离多种高价及低价Ｎ－Ｓ化合物,尤其是能分析三价离子氨基三磺酸根。线性范围分别为：羟胺二磺酸根（０．０９８～６．９６０）×１０－４ｍｏｌ／Ｌ;氨基二磺酸根（０．１２５～１．５０９）×１０－４ｍｏｌ／Ｌ;氨基三磺酸根（０．３８０～３．０４６）×１０－４ｍｏｌ／Ｌ;羟胺一磺酸根（０．０２７～１．２４３）×１０－４ｍｏｌ／Ｌ;氨基一磺酸根（０．０１６～１．１６８）×１０－４ｍｏｌ／Ｌ。实验表明该法具有分析时间短、线性范围宽、灵敏和准确等优点     

高效液相色谱法测定复方感冒液多组分含量

报道了采用高效液相色谱法（ＨＰＬＣ）测定复方感冒液中愈创木酚、扑热息痛、甲基麻黄碱、咖啡因、美沙芬及扑尔敏的含量。色谱柱为ＺｏｒｂａｘＯＤＳ柱,前４种药物采用的流动相为甲醇－０．０５ｍｏｌ／Ｌ磷酸二氢钾－磷酸（２５０∶７５０∶０．５）,检测波长２１４ｎｍ;后２种药物采用的流动相为甲醇－水－磷酸－十二烷基硫酸钠（８０∶２０∶０．５∶０．２）,检测波长２６０ｎｍ。在此色谱条件下,６种药物可获得很好的分离,回收率也高。     

催化动力学光度法测定痕量苯酚

研究了在硫酸介质中苯酚对Ｉ＾－１催化Ｃｅ＾４＋－Ａｓ（Ⅲ）反应的抑制作用及其动力学条件。建立了用催化动力这光度法测定痕量苯酚的新方法，结果表明，在０．００１ｍｏｌ／ＬＣｅ（ＳＯ４）２，０．００１２５ｍｏｌ／Ｌ，Ａｓ２Ｏ３，０．０１ｍｇ／Ｌ，ＫＩ，０．０１２５ｍｏｌ／Ｌ，Ｈ２ＳＯ４和０．１３％（ｗ／ｖ）ＮａＣｌ溶液中测定苯酚，其表面摩尔吸光系数为２．１×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，线性范围     

多组分有机物在玻碳电极上的伏安法测定

对乙酰氨基苯乙醚,氨基比林,乙酰氨基苯酚,氨基苯酚等４种有机物在玻碳电极上的伏安行为进行了研究。在０．１ｍｏｌ／Ｌ氢氧化钠溶液中得到４个灵敏度和分辨率良好的阳极氧化峰。Ｅｐ分别为０．６８,０．５１,０．２２－０．０６Ｖ（ｖｓ．ＡｇＣｌ／Ａｇ）左右,样品不需分离直接测定。     

抑制型离子色谱快速测定I~－、SCN~－、S_2O_3~（2－）

本文用抑制型离子色谱，薄壳强碱性阴离子交换树脂为分离柱，柱温为３０±１℃，在常规淋洗液ＮａＨＣＯ＿３－Ｎａ＿２ＣＯ＿３中加入对－硝基苯酚作为有机改进剂，测定了Ｉ￣－、ＳＣＮ￣－、离子。它们有良好的线性关系，三种离子的浓度在５．０～３０．０ｍｇ／Ｌ范围内其相关系数分别为：０．９９９４、ｒ＿（ＳＣＮ）￣（－０．９９０６），检测限分别为：Ｉ￣－０．１７ｍｇ／Ｌ、ＳＣＮ￣－０．１０ｍｇ／Ｌ、Ｌ。     

高效液相色谱法测定环境水中痕量4,4′-二氨基联苯、4-硝基酚和苯酚

采用ＰｈｅｎｏｍｅｎｅｘＳｐｈｅｒｅｘＣ１８色谱柱,以含５０ｍｍｏｌ／Ｌ乙酸－乙酸钠缓冲溶液（ｐＨ６．０）的Ｖ（乙腈）∶Ｖ（乙醚）∶Ｖ（水）＝１２∶１０∶７８混合溶液为流动相,用分光光度法检测,检测波长为２７５ｎｍ,在１６ｍｉｎ内实现了４,４′－二氨基联苯、４－硝基酚和苯酚的同时分离测定。检测限分别为０．１４,０．１９和０．０８ｎｇ。标准回收率分别为９８．８５％,９８．１５％和９８．１０％。方法灵敏度高,用于环境水样分析时结果令人满意。     

1─（2─吡啶偶氮）─2─萘酚─6─磺酸衍生化反相高效液相色谱法测定铁、钴、镍

本文研究了水溶性试剂１－（２－吡啶偶氮）－２－萘酚－６－磺酸（ＰＡＮ－Ｓ）与铁（Ⅱ）、钴（Ⅱ）和镍（Ⅱ）之螯合物的衍生和液相色谱分离条件。在Ｎｏｖａ－ＰａｋＴＭＣ１８柱上，用含１０ｍｍｏｌ／Ｌ的ｐＨ５．０的醋酸－醋酸钠缓冲溶液的甲醇－水溶液（５０：５０，Ｖ／Ｖ）作流动相，溴化四丁基铵（ＴＢＡ·Ｂｒ）作离子对试剂，流动相流速为１．０ｍＬ／ｍｉｎ，在５５０ｎｍ波长处进行光度检测。在Ⅱｍｉｎ内用高效液相色谱分离测定了Ｆｅ（Ⅱ）、Ｃｏ（Ⅱ）和Ｎｉ（Ⅱ）与ＰＡＮ—Ｓ的螯合物，提出了离子对反相高效液相色谱快速分离测定痕量铁、钴、镍的新方法。信噪比（ＳＮＲ）为２时，检测下限分别为０．０４３、０．００７和０．０１２ｍｇ／Ｌ。     

碘的凝胶色谱测定方法

建立了碘折凝胶色谱测定方法。色谱条件为：Ｓｈｉｍ－ｐａｃｋ ＤＩＯＬ－１５０柱；流动相甲醇０．０１ｍｏｌ／Ｌ Ｈ３ＰＯ４（１０：９０）流速为１．２ｍＬ／ｍｉｎ；柱温为３５℃，检测波长为２２４ｎｍ；线性范围是０．０１０－１．０ｍｇ／Ｌ，相关系数为０．９９９３，检测限为０．００１ｍｇ／Ｌ，相对标准偏差为１．２％－４．６％；回收率为９１％－９８％。所建立的方法已用于食盐，尿，系带等样品的测试，均取得较好     

硅钼杂多阴离子薄膜修饰电极线性扫描伏安法测定黑液中可溶性硅

本文报导了以玻碳电极为基体的１：１２硅钼杂多阴离子薄膜化学修铈电极的制备及其电化学特性。并应用于导数伏安法测定。在４．０×１０￣（－３）ｍ０ｌ／Ｌ（ＮＨ＿４）＿６ＭＯ＿７Ｏ＿（２４）－６．８×１０￣（－２）ｍｏｌ／ＬＮａ＿３Ｃｉｔ－０．４８ｍｏｌ／ＬＮＨＯ＿３体系中，硅浓度在８．３×１０￣（－７）～１．７×１０￣（－３）ｍｏｌ／Ｌ范围内与峰电流呈良好线性关系，检测限为８．０×１０￣（－７）ｍｏｌ／Ｌ。对可溶性硅（以ＳｉＯ＿２计）为２４５．０５ｍｇ／Ｌ的黑液，稀释１０倍后，取２．００ｍＬ平行测定９次，ＲＳＤ为０．５８％，加标回收率在９７．３％～１０４．４％间。     

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.