萃取色谱分离—原子发射光谱测定超高纯氧化铥,氧化镱和氧化镥中痕…

用２－乙基己基膦酸单２乙基己酯萃取色说分离－原子发射光谱测定超高纯Ｔｍ２Ｏ３，Ｙｂ２Ｏ３，Ｌｕ２Ｏ３中痕量稀土杂质，可用于纯度为９９．９９９９％－９９．９９９９９％Ｔｍ２Ｏ３，Ｙｂ２Ｏ３，ｌＵ２ｏ３的纯分分析，１４个稀土杂质的回收率在６７％－１３３％之间；相对标准偏差５．１％－２３．２％，分离周期１０－１３ｈ。     

萃取色谱分离-原子发射光谱测定超高纯氧化铥、氧化镱和氧化镥中痕量稀土杂质

用２－乙基己基膦酸单２－乙基己酯萃取色谱分离－原子发射光谱测定超高纯Ｔｍ２Ｏ３、Ｙｂ２Ｏ３、Ｌｕ２Ｏ３中痕量稀土杂质，可用于纯度为９９．９９９９％～９９．９９９９９％（不含非稀土杂质）Ｔｍ２Ｏ３、Ｙｂ２Ｏ３、Ｌｕ２Ｏ３的纯度分析，１４个稀土杂质的回收率在６７％～１３３％之间；相对标准偏差 ５．１％～２３．２％；分离周期 １０～１３ ｈ。     

流动注射化学发光抑制法测定抗坏血酸

基于抗坏血酸对Ｌｕｍｉｎｏｌ－ＫＩＯ４－Ｈ２Ｏ２体系化学发光反应的抑制作用,建立了化学发光抑制快速测定抗坏血酸的新方法。该方法线性范围为１．０＊１０＾－７－１．０＊１０＾－５ｍｏｌ／Ｌ,检出限为６．０＊１０＾－８ｍｏｌ／Ｌ,对８．０＊１０＾－７ｍｏｌ／Ｌ抗坏血酸１１次平行测定的相对标准偏差为１．０％。用于维生素Ｃ片剂及注射液中抗坏血酸含量的测定,结果令人满意。     

单柱离子色谱法测定痕量草酸根离子

本文采用单柱离子色谱系统测定了Ｃ２Ｏ＾２－４，以１．３ｍｍｏｌ／Ｌ葡萄糖酸钠／１．３ｍｍｏｌ／Ｌ硼砂为淋洗液测定Ｃ２Ｏ＾２－４，８常见阴离子Ｃｌ＾－，ＮＯ＾－３，ＨＰＯ＾２－４，ＳＯ＾２－４不干扰测定，Ｃ２Ｏ＾２－４的检出限为０．５７ｍｇ／Ｌ，相对标准偏差为１．０７％，工作曲线的线性范围为０．５７－５００ｍｇ／Ｌ，应用本方法测定了加Ｃ２Ｏ＾２－４的自来水样，Ｃ２Ｏ＾２－４的回收率为９９．５２％。     

化学分离—质谱法定量分析高纯Dy2O3中稀土杂质

以Ｐ５０７萃淋树脂为固定相，ＨＣｌ－ＮＨ４Ｃｌ为淋洗液，研究了９９．９９９％－９９．９９９９％高纯Ｄｙ２Ｏ３中痕量稀土与基本Ｄｙ的分离法，以及火花源谱法的测定条件。可分析９９．９９９９％超高纯Ｄｙ２Ｏ３中痕量稀土杂质，测定限０．００１－０．１×１０＾－６，误差３０％。     

络合吸附波极谱法测定稀土钢中微量稀土

研究了在ｐＨ９．２－ｐＨ９．５的ＮＨ３０Ｎａ２Ｂ４Ｏ７介质中,稀土与百里香酚酞的络合物极谱波,波高与镧量在４．０×１０＾－７－３．６×１０＾－６ｍｏｌ／Ｌ范围内成线性关系。方法已用于稀土钢中微量稀土的测定。     

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     

漆树漆酶的催化氧化作用（ⅫⅡ）

以５,６－二溴－２,３－二氰基氢醌为底物,在ＰＨ４．５０条件下,用分光光度法考察了ＦｅＳＯ４对漆树漆酶催化氧化反应的影响。结表明,在本文实验条件下ＳＯ４＾２－离子对酶促反应的影响基本可以忽略,而Ｆｅ＾２离子对漆酶的催化氧化反应则有明显的竞争性抑制作用,研究证实,Ｆｅ＾２＋离子的抑制作用是通过它还原酶促反应的产物半醌自由基阴离子来实现的。     

NO^—2离子的光催化反应研究（Ⅱ）

研究了ＮＯ＾－２离子在ＴｉＯ２表面的光催化反应,结果表明,体系ｐＨ值升高及Ｃｒ,Ｃｌ＾－,ＳＯ＾２－４离了的加入均对ＮＯ＾－２离子在ＴｉＯ２表面的暗态吸附产生抑制作用,而ＮＯ＾－２在ＴｉＯ２表面的光照反应转化率则随ｐＨ值的升高出现先减小后增大的总体变化趋势。     

天然气和二氧化碳转化制合成气的研究：Ⅵ Ni／Al2O3催化剂再生的疏…

采用γ－Ａｌ２Ｏ３为载体，以硝酸镍，硝酸镁和稀土硝酸盐为原料，按常规浸渍法制备负载型催化剂，其中Ｎｉ含量为９．１７％，助剂ＲＥ２Ｏ３和Ｍｇ含量分别为５．１８％和１．８０％。该催化剂简称为Ｎ－５－ＲＭ。催化反应评价采用双套管石英反应器，在多功能固定床流动反应装置上进行。     

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.