催化动力学光计法测定微量碘的研究

基于微量碘离子对高碘酸钠氧化甲基紫反应的催化作用，建立了测定微量碘的动力学光度法。方法检出限０．２２μｇ／ｍＬ线性范围０．３０－１．４０μｇ／ｍＬ，包括其它卤素在内的大多数阴离子、阳离子不干扰测定，用于食盐中微量碘的测定，有满意的结果。     

吐温80—AuCl4^—化学发光新体系测定痕量碘离子的研究

基于碘离子对吐温８０－ＡｕＣｌ４＾－体系化学发光的强烈抑制作用,提出了一种测定痕量碘离子的新的化学发光分析法。方法的线性范围和检测分别为１．２×１０＾－８￣１．０×１０＾－６ｇ／ｍＬ和５．１×１０＾－９ｇ／ｍＬ碘离子。拟定的方法体系简单,选择性好,加碘酱油和实际水样中碘离子的测定,结果满意。     

催化褪色光度法测定痕量铁的研究

研究了在ｐＨ４．５的弱酸性介质中，利用邻菲罗啉活化过氧化氢氧化紫脲酸铵褪色的指示反应，建立了催化动力学光度法测定痕量铁的新方法，方法的检出限为６．５×１０＾－７ｇ／Ｌ线性范围为０～１．０μｇ／２５ｍＬ，用于水，粮食中痕量铁的测定，结果满意。     

催化动力学光度法测定微量碘的研究

基于微量碘离子对高碘酸钠氧化甲基紫反应的催化作用，建立了测定微量碘的动力学光度法。方法检出限０．２２μｇ／ｍＬ，线性范围０．３０～１．４０μｇｍＬ，包括其它卤素在内的大多数阴离子、阳离子不干扰测定，用于食盐中微量碘的测定，有满意的结果。     

催化动力学光度法测定痕量硫离子

基于氢氧化钠溶液中，Ｓ~（２－）对Ｈ_２Ｏ_２氧化Ｉ－的反应有催化作用，固定反应时间，将此催化体系与二苯胺碘酸钠氧化显色反应相偶合，建立了催化动力学光度法测定痕量硫离子的新方法，并讨论了其动力学条件。方法灵敏度１．４×１０~（－１１）ｇ／ｍＬ，测定范围１．０～１２．０ｎｇ／ｍＬ。操作简便快速，用于测定天然水及含硫工业废水中的痕量硫离子，结果满意。     

IO~－_3－I~－_－结晶紫－阿拉伯胶体系分光光度法测定生物样品中的碘

在硫酸介质中，在过量碘化钾及阿拉伯胶存在下，ＩＯ－３氧化Ｉ－生成Ｉ－３，Ｉ－３再与结晶紫形成离子缔合物，缔合物的最大吸收波长为５５２ｎｍ，表观摩尔吸光系数ε５５２＝５．３８×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，ＩＯ－３量在０～１２μｇ／２５ｍＬ范围内服从比耳定律．用于生物样品中碘的测定，结果满意     

测定利福平的化学发光新体系

基于碱性介质中铜离子催化过氧化氢可氧化利福平产生化学发光这一现象，并结合流动注射分析技术建立起了一种测定利福平的新方法。该方法测定利福平的线性范围为 ４ × １０－７× １０－４ｇ／ｍｌ，方法的检出限为 ７× １０－８ｇ／ｍＬ，７次平行测定 ２ × １０－５ｇ／ｍＬ利福平的相对标准偏差为 ４．９％。成功地用于利福平眼药水中利福平含量的测定。     

差示分光光度法测定药物制剂中的四环素

提出了四环素与钴离子络合反应测定四环素的新方法,线性范围为０．８－２５μｇ／ｍＬ,ε＝１．３３＊１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１,回收率为９７．８％－１０１．５％。方法已用于制剂中四环素的测定。     

高碘酸盐氧化罗丹明B催化光度法测定钌

在０．７２ｍｏｌ／Ｌ磷酸和９０℃水浴条件下,钌催化高碘酸盐氧化罗丹明Ｂ（ＲＢ）,据此建立了高灵敏催化光度测定钌的方法。方法的检出限为８．０×１０＾－１２ｇ／ｍＬ,测定范围为０．２～１５ｎｇ／２５ｍＬ,对５、１０、１５ｎｇ／２５ｍＬＲｕ（Ⅲ）测定的相对标准偏差分别为８．６７％,５．９４％和１．８５％。本反应对Ｒｕ（Ⅲ）、ＲＢ、ＫＩＯ４和Ｈ３ＰＯ４均为一级反应,表观活化能为３６．０５ｋＪ／ｍｏｌ。１３     

催化褪色光度法测定痕量钴的研究

研究了在ＰＨ１０．５的Ｎａ２Ｂ４Ｏ７－ＮａＯＨ介质中，痕量钴（Ⅱ）对过氧化氢氧化桑色素初色反应的催化作用，建立了催化动力学光度法测定痕量钴的新方法。方法的线性范围为０－１．２μ／ｍＬ检出限为４．４＊１０＾－１８ｇ／Ｌ。用于水和维生素Ｂ１２中钴的测定，结果满意。     

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%.     

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.     

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%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

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.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

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.