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％。     

低压离子色谱法测定天然水中Cl~-,NO_3~-和SO_4~(2-)

利用低压离子色谱法（电导检测器）测定了沈阳地区自来水、湖水、河水和雨水中的Ｃｌ－，ＮＯ－３和ＳＯ２－４。当以１．４４ｍｍｏｌ／ＬＮａ２ＣＯ３作淋洗液、流速为１．２ｍＬ／ｍｉｎ时，分离效果良好，３种阴离子的检出限分别为０．０１３６，０．２０４和０．１６１ｍｇ／Ｌ，回收率为９０％～１０４％。选定的色谱条件同样适用于ＮＯ－２和ＳＯ２－３的测定。重点讨论了用低压离子色谱法测定阴离子时在选用淋洗液组成上的局限性。     

低压离子色谱法测定天然水中Cl~-,NO_3~-和SO_4~(2-)

 利用低压离子色谱法（电导检测器）测定了沈阳地区自来水、湖水、河水和雨水中的Ｃｌ－，ＮＯ－３和ＳＯ２－４。当以１．４４ｍｍｏｌ／ＬＮａ２ＣＯ３作淋洗液、流速为１．２ｍＬ／ｍｉｎ时，分离效果良好，３种阴离子的检出限分别为０．０１３６，０．２０４和０．１６１ｍｇ／Ｌ，回收率为９０％～１０４％。选定的色谱条件同样适用于ＮＯ－２和ＳＯ２－３的测定。重点讨论了用低压离子色谱法测定阴离子时在选用淋洗液组成上的局限性。     

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要溶性硅

本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＾－３ｍｏｌ／Ｌ９ＮＨ４）６Ｍｏ７Ｏ２４－６６．８×１０＾－２ｍｏｌ／ＬＮａ３Ｃｉｔ－０．４８ｍｏｌ／Ｌ ＮＨＯ３体系中，硅浓度在８．３×１０＾－７～１．７×１０＾－３ｍｏｌ／Ｌ。对可溶性硅（以ＳｉＯ２计）为２４５．０５ｍｇ／Ｌ的黑液，稀释１０倍后，取２．００ｍＬ平行测定     

ZrO2及SO^2—4／ZrO2超强酸催化剂的XRD分析

用ＸＲＤ技术从定性和定量上对ＺｒＯ２，特别是ＳＯ＾２－４／ＺｒＯ２超强酸催化剂的物相和四方相ＺｒＯ２的含量进行了详细的考察。结果表明，ＳＯ＾２－４的引入使ＳＯ＾２－４／ＺｒＯ２的晶化温度比ＺｒＯ２大约提高了１００Ｋ，并且使亚稳态四方相ＺｒＯ２得以稳定。亚稳态四方相ＺｒＯ２的含量主要受处理液浓度和焙烧温度的影响。处理液浓度越大，四方相含量越高；焙烧温度越高；四方相含量越低。强酸性的Ｈ２ＳＯ４溶液比弱     

示波极谱法测定内燃机车冷却液中亚硝酸根含量

采用ＪＰ３－１型示波极谱仪，滴东电极１．５次微分，在－０．６～－１．９０Ｖ范围内，通过对多种底液组分的试验，确定了在２．００×１０＾－３ｍｏｌ．Ｌ＾－１Ｍｎ＾２＋，盐酸（ｐＨ２）底液中，ＮＯ＾－２在－１．３２Ｖ（ｖｓ．ＳＣＥ）处于生极谱法，ＮＯ２浓度在４．００×１０＾－５～４．００×１０＾－３ｍｏｌ．Ｌ＾－１范围与峰高呈线性关系。方法可用于测定内燃机车冷却液中ＮＯ２含量，其选择性好，操作简便，快速     

低压离子色谱法在酸雨分析中的应用

低压离子色谱是作者提出的一种新的分析法，可以在１．９６～２．９４×１０＾５Ｐａ低压分析碱金属，碱土金属，过渡金属阳离子，无机阴离子及许多有机酸离子，本文用低压离子色谱法分析了成都地区酸雨中Ｎａ，ＮＨ４，Ｋ＾＋，Ｍｇ＾２＋，Ｃａ＾２＋，Ｆ＾－，Ｃｌ＾－，ＮＯ３＾－，ＳＯ＾２－４等离子，获得了满意的结果。     

离子色谱法测定矿物药中可溶性砷（Ⅲ）和砷（Ⅴ）

离子色谱法测定了矿物药雄黄，雌黄在盐酸配制的人工胃液中可溶性砷和砷。对淋洗液的组成及流速进行了选择。以流速为１．０ｍＬ／ｍｉｎ的３．５ｍｍｏｌ／Ｌ Ｎａ２ＣＯ３淋洗液在ＹＳＣ－４Ａ阴离子交换柱上分离，ＹＳ－Ｚ柱抑制，ＨＬＣ－６０１离子色谱仪电导检知器检测。     

以双核有机锡化合物为载体的PVC膜磷酸根离子敏感电极

以双（三苄基锡）氧化物为载体制备了一种对磷酸氢根离子具有良好电位响应性能的溶剂聚合膜离子敏感电极。在ｐＨ为７．２０±０．０２的测试液中，电极的线性响应范围为５ ×１０＾－６￣１０＾－１ｍｏｌ／Ｌ，斜率为－３０．１ｍＶ／ｄｅｃ．．用分别溶液法测得其对于各种阴离子的选择性次序：ＨＰＯ４＾２－￣Ｉ＾－〉Ｂｒ＾－〉Ｃｌ＾－〉Ａｃ〉ＳＯ４＾２－。膜相中荷电离子添加实验的结果表明，电极响应系中性载体作用机制。     

低酸度淋洗液离子色谱法测定多聚磷酸盐

在国产阴离子分离柱上采用含钙和镁离子的淋洗液，由于Ｃａ＾２＋和Ｍｇ＾２＋与复杂的多聚磷酸根离子形成螯合物而提高了淋洗能力，加快了分析速度，大大降低了淋洗液的酸度和盐浓度，对几种工业三聚磷酸钠样品进行了测定，与化学法相比，相对误差小于１．５％，加入回收率在９９％－１０９％之间。     

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%.     

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.     

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.     

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.     

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.     

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.