硫羟乳酸作为络合滴定掩蔽剂的研究

本文系统地研究了硫羟乳酸在络合滴定中的掩蔽性能。发现在ｐＨ３．０用ＥＤＴＡ滴定了Ｔｈ＾４＋时，可用它掩蔽Ｓｎ＾４＋，Ｔｌ＾３＋，Ｓｂ＾３＋，Ｂｉ＾３＋，Ｂｈ＾２＋和Ｃｕ＾２＋。在ｐＨ５．５滴定Ｙｂ＾３＋，Ｌａ＾３＋或Ｃｅ＾３＋时，可用它掩蔽Ｓｎ＾４＋，Ｔｌ＾３＋，Ｓｂ＾３＋，Ｂｉ＾３＋，Ｈｇ＾２＋，Ｃｕ＾２＋和Ｃｒ＾３＋，在ｐＨ１０．０滴定Ｍｇ＾２＋时，可用它掩蔽Ｓｎ＾４＋，Ｔｌ＾３＋，Ｓｂ＾３＋     

植酸在络合滴定铜时作为掩蔽剂的研究

研究了植酸在络合滴定铜时的掩蔽性能。发现在ｐＨ５．５或ｐＨ４．５以５－Ｂｒ－ＰＡＤＡＴ为指示剂,用ＥＤＴＡ滴定Ｃｕ＾２＋时,可以用植酸掩蔽Ｆｅ＾３＋、Ａｌ＾３＋,Ｓｎ＾４＋、Ｔｉ＾４＋、Ｔｈ＾４＋、Ｌａ＾３＋和Ｃｅ＾３＋。本法已用于测定锡青铜,磷青铜和铝青铜中的铜。     

催化光度返滴定法测定微量锰的研究

本文研究了催化光度反滴定法测定微量锰的原理，找到最佳实验条件，确立了实验方法，测定波长６２２ｎｍ；反应时间１ｍｉｎ４０ｓ；活化剂ＮＴＡ用量０．６０ｍＬ，ＫＩＯ４与孔雀石绿用量比为１．００：０．３５，室温下滴定；用ｐＨ＝５．４的乙酸－乙酸钠缓冲溶液控制溶液酸度；测定Ｍｎ＾２＋的浓度范围为１×１０＾－７～１×１０＾－５ｍｏｌ／Ｌ，Ｃｏ＾２＋，Ｂｉ＾３＋，Ｃａ＾２＋，Ａｌ＾３＋，Ｐｂ＾２＋，Ｃｕ＾２＋，     

合并带流动注射分光光度法研究硫羟乳酸掩蔽性能

本文运用合并带流动注射分析技术，建立了以Ｙｂ＾３＋ＸＯ显色体系为参考体系研究硫羟乳酸掩蔽性能的方法，在ｐＨ５．６硫羟乳酸能掩蔽Ｓｎ＾４＋，Ｂｉ＾３＋，Ｔｌ＾３＋，Ｈｇ＾２＋，Ｃｕ＾２＋，Ｃｒ＾３＋和Ｃｄ＾２＋测定Ｙｂ＾３＋的线性范围为１．３６×１０＾－６～２．７２×１０＾－５ｍｏｌ／Ｌ，采样频率可达１２０次／ｈ。     

核级银铟镉合金中Ag In Cd 的连续滴定

研究了测定核级银铟镉合金中Ａｇ、Ｉｎ、Ｃｄ的连续滴定法。以电位滴定法测定Ａｇ；在ｐＨ２．５以ＥＤＴＡ滴定Ｉｎ；在ｐＨ≥５．５以ＥＤＴＡ滴定Ｃｄ，当ｎ＝１１时，其ＲＳＤ分别为：Ａｇ０．１１％、Ｉｎ０．５２％、Ｃｄ１．１％，合成试样分析回收率分别为：Ａｇ９９．８％～１００．１％、Ｉｎ９９．６％～１００．３％、Ｃｏ９７．６％～１０１．３％，测定９２个合金试样，其Ａｇ，Ｉｎ，Ｃｄ合量范围为：９９．７８％～     

Eu^3＋,Bi^3＋Me2Y8（SiO4）6O2中的发光特性与取代格位

在紫外光激发下，Ｅｕ＾３＋和Ｂｉ＾３＋在Ｍｅ２Ｙ８（ＳｉＯ４）６Ｏ２基质（Ｍｅ＝Ｍｇ，Ｚｎ，Ｃａ，Ｓｒ）中分别发射红光（＾５Ｄ０－＾７Ｆ２）和蓝光（＾３Ｐ１－＾１Ｓ０）．Ｅｕ＾３＋发光的红橙比随着激发波长和Ｍｅ＾２＋的不同而变化。荧光拉曼光谱表明，Ｅｕ＾３＋在四种基质中同时占据了４ｆ格位和６ｈ格位。依据Ｂｉ＾３＋发光的Ｓｔｏｋｅｓ位移推断，当Ｍｅ＝Ｃａ，Ｚｎ时，Ｂｉ＾３＋主要占据４ｆ格位，而当Ｍｅ     

Eu^2＋和Mn^2＋在Sr3MgSi2O8中的光致发光研究

研究了Ｅｕ＾２＋和Ｍｎ＾２＋共激活的Ｓｒ３ＭｇＳｉ２Ｏ８的荧光性质。Ｅｕ＾２＋和Ｍｎ＾２＋在４６０ｎｍ和６９０ｎｍ的发射峰分别由Ｅｕ＾２＋的５ｄ→４ｆ跃迁和Ｍｎ＾２＋的＾４Ｔ１（＾４Ｇ）→＾６Ａ１ｇ（＾６Ｓ）跃迁产生。未观察到单掺杂Ｍｎ＾２＋的Ｓｒ３ＭｇＳｉ２Ｏ８的荧光发射，而掺入Ｅｕ＾２＋后则出现了Ｍｎ＾２＋的６９０ｎｍ光致发光峰，表明Ｅｕ＾２＋对Ｍｎ＾２＋有敏化作用。Ｅｕ＾２＋的荧光寿命也受Ｍ     

水溶液中四氮杂四乙酸大环与金属离子络合物的稳定性

本文采用ｐＨ电位滴定技术和计算机拟合，获得在２０，２５，３０和４０℃，０．５ｍｏｌ／Ｌ ＫＣｌ水溶液中Ｈ４Ｌ（５，１２－二苯基－７，１４－二甲基－１，４，８，１１－四氮杂环十四烷－四乙酸）的分步加质子常数及反应热焓值。又在４０℃条件下测定了Ｈ４Ｌ与Ｃｕ＾２＋，Ｎｉ＾２＋，Ｃｏ＾２＋，Ｚｎ＾２＋，Ｍｎ＾２＋，Ｃｄ＾２＋，Ｍｇ＾２＋，Ｃａ＾２＋，Ｓｒ＾２＋，Ｂａ＾２＋络合物的稳定常数，并对结果进行了讨     

离子浮选石墨炉原子吸收光谱法测定水中痕量Cr（Ⅵ）／Cr（Ⅲ）

本文以二苯卡巴肼（ＤＰＣＩ）和十二烷基硫酸钠（ＳＬＳ）为浮选剂研究了分离浓缩（Ｃｒ（Ⅵ）的最佳条件，建立了水中痕量络的形态分析方法。该方法简单、快速、检测限０．０３μｇＬ＾－１，变异系九小于４％，２００ｍＬ水样中含ＮＯ３５０，Ｎａ＾＋，Ｍｇ＾２＋４０，Ｃｌ２８，Ｄ，Ｃａ＾２＋，ＳＯ４１０，ＣＯ３９，Ａｌ＾２＋，Ｃｏ＾２＋，Ｎｉ６２＋５，Ｍｎ＾２，Ｐｂ＾２＋２．５，Ｆｅ＾３＋０．２ｍｇ不影响测定。方     

置换络合极谱双点滴定法

本文提出了络合极谱双点滴定中置换滴定法的测定方法和定量公式，研究了以ＥＤＴＡ为络合剂，在ＨＡｃ－ＮａＡｃ缓冲溶液中，以乳酸置换与Ｓｎ＾４＋络合的ＥＤＴＡ，以ＣｄＣｌ２标准溶液为滴定剂测定Ｓｎ。对于５×１０＾－５ｍｏｌ的Ｓｎ，回收率达９９．２％。应用该法于青铜样品中Ｓｎ的含量的测定，结果较为满意。     

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%.     

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.     

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.     

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.     

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.