金属-有机骨架MIL-101(Cr)掺杂聚合物整体柱的制备及其用于酚类化合物的在线固相萃取

制备了金属-有机骨架（MOF）MIL-101（Cr）掺杂聚合物整体柱，建立了在线固相萃取-高效液相色谱检测水中4-硝基苯酚、2-硝基苯酚、3-甲基苯酚和2，4-二氯苯酚的方法。考察了样品溶液pH值、上样时间、上样流速和解吸时间对酚类化合物萃取效果的影响。在最优萃取条件下，采用制备的整体柱检测水中酚类化合物，其富集因子高，线性范围宽，精密度好，检出限低，适用于水中酚类化合物的检测。制备掺杂聚合物整体柱是促进和拓宽MOFs在线固相萃取应用的有效方法之一。     

固相萃取-气相色谱-串联质谱法检测水中18种酚类化合物

当前水中酚类化合物种类不清、危害不明，多种酚类化合物的同时检测方法不成熟，因此建立水中多种酚类化合物同时检测的方法具有重要现实意义。该研究建立了固相萃取结合气相色谱-串联质谱同时检测水中18种酚类化合物的分析方法。实验选择超纯水为空白样品，采用固相萃取技术富集、提取水中的酚类化合物，同时对水样初始pH值、洗脱液的种类、洗脱液的用量等条件进行优化，从而确定出最优的前处理方法，最后利用气相色谱-串联质谱法对不同种类的酚类化合物同时进行定量检测。实验结果表明，在初始水样pH值为3.0、不衍生等条件下，使用10 mL乙酸乙酯洗脱，控制洗脱速度为1 mL/min，经固相柱富集净化，氮吹浓缩后，用气相色谱-质谱仪（EI源）测定，选择离子模式监测，外标法定量。结果表明，以3倍信噪比结合浓度外推法确定方法检出限，为0.04~0.6 μg/L；18种酚类化合物的加标回收率为51.7%~117.3%，相对标准偏差为3.1%~7.4%。应用建立的方法分别检测了河流湖泊水、生活用水、生产用水3大类6种不同的水质。检测结果表明，河流湖泊水中酚类化合物所含种类最多，含量最高。研究建立的方法不需要衍生，简化了前处理方法，操作简单，且准确性高，重复性好，可同时检测复杂水体中多种酚类化合物，能显著提高酚类化合物的分析速率。该方法的建立对我国水中酚类化合物残留水平的控制、检测标准的制定和管理措施的采取，都具有重要的理论和现实意义。     

固相微萃取-气相色谱-质谱联用分析水中的痕量扑草净

研究了固相微萃取－气相色谱－质谱联用测定水中扑草净的方法，采用聚丙烯酸酯（PA）萃取头，对影响固相微萃取萃取效率的萃取时间、搅拌速度、pH值以及盐度等进行了优化。在优化实验条件下，方法线性范围在0．1mg/mL-1000ng/mL之间，检出限为1．5ng/L。用该法分析了合成井水、自来水和湖水样品，回收率在85．4％－89．1％之间，相对标准偏差在1．8％－5．2％之间。本方法适合于水中痕量扑草净的分析。     

水中酚类化合物的液-液-液微萃取/ 高效液相色谱联用分析研究

建立了液-液-液微萃取/高效液相色谱联用(LLLME/HPLC)测定环境水中痕量酚类化合物2-甲基苯酚、2-硝基苯酚、2,4-二氯苯酚的分析方法,研究了有机相溶剂种类及其体积、料液相pH值与离子强度、接受相的体积、组成及浓度和搅拌速率、萃取时间等因素对分析物萃取效率的影响。实验结果表明,该方法对酚类化合物的富集倍数可达到404~747倍,方法的线性范围为0.2~300μg/L,RSD(n=6)为6.8%~11.4%。测定加标自来水、江水以及生活污水样品的回收率为83%~110%。     

中空纤维三相液相微萃取-高效液相色谱法测定水中的4种酚类化合物

建立了中空纤维液-液-液三相微萃取-高效液相色谱法测定水中4种酚类化合物的方法.实验系统地优化了影响萃取效率的因素(包括有机溶剂种类、接收相浓度、分散相pH值、加盐量、转速及萃取时间).得到的最佳萃取条件为:萃取剂为正辛醇,接收相NaOH溶液的浓度为0.09 mol/L,分散相的pH为4,萃取时间为40 min,搅拌速...     

固相膜萃取/气相色谱-质谱法检测水体中痕量酚类化合物

建立了固相膜萃取/气相色谱-质谱法同时测定水体中多种痕量酚类化合物的分析方法。采用固相膜萃取技术提取水中的痕量酚类化合物,对洗脱液种类、洗脱液体积、水样初始p H值和洗脱速率等萃取条件进行优化,并用DB-5MS色谱柱分离,气相色谱-质谱法(GC-MS/SIM)进行定量测定。实验结果表明,在p H 2.0的初始条件下,选择10 m L乙酸乙酯-二氯甲烷混合溶液(体积比1∶1)作为洗脱剂,控制洗脱速率为1 m L/min时,酚类化合物的平均回收率高达82.3%~97.1%。在1~800μg/L质量浓度范围内,酚类化合物的峰面积与对应质量浓度呈良好线性关系,相关系数(r2)均在0.996以上,检出限均不大于0.017μg/L,相对标准偏差(RSD,n=8)为1.6%~4.3%。将方法应用于我国北江流域水样检测,结果可靠。该方法萃取时间短、灵敏度和准确度高、简单易行,满足实际水体中对痕量酚类化合物的检测要求,可显著提高水中痕量酚类化合物的分析效率。     

聚醚砜酮涂层纤维顶空固相微萃取-气相色谱法分析水中痕量的酚类化合物

应用自制的聚醚砜酮(PPESK,30 μm)涂层纤维,采用顶空固相微萃取-气相色谱法测定水中痕量的酚类化合物。优化了固相微萃取温度、萃取时间、pH值和离子强度。方法的检出限为0.003～0.041 μg/L,相对标准偏差低于16%(n=5)。将PPESK涂层纤维与商品化的聚丙烯酸酯涂层纤维对比,结果表明PPESK萃取酚类化合物有较高的萃取富集倍数。用所制备的PPESK萃取头分析自来水、海水等实际水样,20 μg/L添加水平下的回收率分别为100.5%～111.8%和94.8%～117.3%。     

2-(2-喹啉偶氮)-1,5-苯二酚固相萃取光度法测定饮用水中铜的研究

根据新试剂2－（2－喹啉偶氮）－1，5－苯二酚（QADHB）与铜的显色反应及Waters Porapak Sep-Park固相萃取小柱对显色络合物的固相萃取，建立了一种测定水样中铜的新方法。在pH=4.0 HAc-NaAc缓冲介质中，溴化十六烷基三甲基铵（CTMAB）存在下，QADHB与铜反应生成2：1稳定络合物，该络合物可用Waters Porapak Sep-Park固相萃取小柱富集，用乙醇洗脱后用光度法测定，可测定水柱中μg/L级的铜。方法用于几种饮用水中铜的分析，结果令人满意。     

非平衡固相微萃取-气相色谱-质谱联用快速监测水中的氯化苄

建立了一种非平衡固相微萃取与气相色谱－质谱联用快速监测水中氯化苄的新方法，整个分析过程只需15min。85μm的聚丙烯酸酯涂层（PA）对水中的氯化苄有较好的萃取效果。方法的线性范围为1－50μg/L，检出限为0．91μg/L，相对标准偏差为9．86％，用于河水中氯化苄的测定，结果满意。     

SPME-GC联用测定环境水样中的酚类化合物

建立了固相微萃取与气相色谱联用技术测定环境水样中酚类化合物的方法. 探讨了pH、离子强度、萃取头类型、萃取时间以及解析时间等条件对酚类化合物萃取量的影响, 优化了GC仪器条件. 在优化的条件下, 酚类化合物的响应值与浓度有良好的线性关系, 线性范围为0.20～200 μg/L, 检出限在0.019～0.10 μg/L之间, 相对标准偏差(RSD, n=5)为4.4%～11%, 水样平均加标回收率为92.2%～101.9%, 所建立的方法可测定环境水样中的酚类化合物.     

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%).     

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.     

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.     

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.