动力学分光光度法测定痕量亚硝酸根和硫氰酸根的研究

基于亚硝酸根对溴酸钾氧乙基橙反应的催化作用及硫氰酸根对此反应的抑制作用，建立了动力学光度法测定痕量亚硝酸根和硫氰酸根的新方法，测定亚硝酸根的线性范围为５－１００μｇ／Ｌ，测定硫氰酸根的线性范围为３－１２μｇ／Ｌ，用于湖水和蔬菜中的亚硝酸根量及化学试剂和尿中的硫氰酸根测定，结果满意。     

亚甲紫分光光度法测定微量亚硝酸根

研究了在盐酸介质中微量亚硝酸根与亚甲紫发生的重氮化反应,建立了测定微量亚硝酸根的新方法。方法的线性范围为８－４４０μｇ／Ｌ ＮＯ＾－２,检出限为８μｇ／Ｌ ＮＯ＾－２方法已用于水中微量亚硝酸根的测定,并对反应机理了初步讨论。     

动力学催化光度法测定痕量亚硝酸根

磷酸和棉红在１００℃下反应生成天蓝色物质（λｍａｘ＝６７５ｎｍ）,该物质在痕量亚硝酸根的催化下被ＫＢｒＯ３氧化褪色,研究了反应的条件,测定了动力学参数,建立了测定痕量亚硝酸根的方法,方法检出限是４＊１０＾－１０ｇ／ｍＬ,测定范围是０．４０－２０．００μｇ／Ｌ,用于水体中痕量亚硝酸根的测定,结果满意。     

碘化物—罗丹明B体系荧光猝灭反应测定痕量亚硝酸根

拟定了一个荧光猝灭法测量痕量亚硝酸根的新方法。在盐酸介质中，亚硝酸根氧化碘化钾的反应，其反应物Ｉ＾－３使罗丹明Ｂ荧光猝灭，方法的检出限为３．６μｇ／Ｌ；测定范围为１０－１２０μｇ／Ｌ。方法简便快速，选择性好，用于自来水，矿泉水及合成样品中亚硝酸根的测定，结果满意。     

碘化物-罗丹明B体系荧光猝灭反应测定痕量亚硝酸根

拟定了一个荧光猝灭法测定痕量亚硝酸根的新方法。在盐酸介质中，亚硝酸根氧化 碘化钾的反应，其反应产物Ｉ３－使罗丹明Ｂ荧光猝灭。方法的检出限为３．６μｇ／Ｌ；测定范围为 １０～１２０μｇ／Ｌ。方法简便快速、选择性好，用于自来水，矿泉水及合成样品中亚硝酸根的测定， 结果满意。     

亚硝酸根的催化光度法测定

本法基于甲酸介质中，亚硝酸根对溴酸钾氧化甲基橙褪色的催化效应，用正交法确定最佳测定条件。本法测定亚硝酸根的线性范围为０～０．２０μｇ／ｍＬ灵敏度为２．８３×１０－１０ｇ／ｍＬ。用于测定水样中的亚硝酸根，结果良好。     

痕量亚硝酸根的聚氯乙烯液态膜四氯络铁(Ⅲ)离子电极测定

以新型阴离子载体Ｓ－烷基双硫腙,制备了ＦｅＣｌ＾－４阴离子选择性电极,研究了电极的性能,确定了亚硝酸催化氧化Ｆｅ＾２＋的最佳反应条件,在４ｍｏｌ／Ｌ ＮａＣｌ－０．２ｍｏｌ／Ｌ ＨＣｌ介质中反应５０ｍｉｎ时以尿素终止,反应生成的Ｆｅ（Ⅲ）以ＦｅＣｌ＾－４选择电极电位法测定。间接测定ＮＯ＾－２。线性范围为１５－３５０μｇ／ＬＮＯ＾－２,检出限为８μｇ／Ｌ。该法应用于雪水和水样中亚硝酸根的测定,结果与光度法一致。     

荧光猝灭法测定痕量亚硝酸根

研究了用荧光猝灭法测定了亚硝酸根。本方法是基于亚硝酸根与碘化钾反应生成了单质碘,碘可以使２’,７’０二氯荧光素（ＤＣＦ）发生荧光猝灭,从而间接测定亚硝酯根。亚硝酸根浓度在１０￣１２０μｇ／Ｌ范围内,荧光强度差值与亚硝酸根浓度呈线性关系。检测限为５．６μｇ／Ｌ。本法简便、灵敏度较高,已用于合成样和分析纯试剂中亚硝酸根的测定。     

亚硝酸根—对氨基苯磺酸—H酸偶联反应体系光度法测定亚硝酸根的研究

本根据亚硝酸根与对氨基苯磺酸、Ｈ酸在酸性介质中进行的重氮偶联反应，提出了一个测定痕量亚硝酸根的分光光度新体系。最大吸收波长为５２０ｎｍ摩尔吸光系数为３．１× １０＾４Ｌ／ｍｏｌ．ｃｍ亚硝酸根浓度在０－１．２μｇ／ｍＬ范围内符合比耳定律。用于水样中亚硝酸根的分析，测定结果与经典的α－萘胺法一致。     

溴酸钾氧化吡罗红G催化动力学光度法测定痕量NO2^—

研究了在磷酸介质中亚硝酸根催化溴酸钾氧化吡罗红Ｇ而使褪色，建立了催化动力学光度法测定痕量亚硝酸根的新方法，测定范围为０．２－２０μｇ／ｍＬ，检出限为０．２ｎｇ／ｍｌ，用于食品和水样中的亚硝酸根测定获得满意结果。     

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.