水中氯苯系化合物的固相微萃取

研究了用固相微萃取装置直接从水中萃取氯苯系化合物的条件,试验表明室温下萃取２５～３５ｍｉｎ效果最佳。随着氯苯系化合物含量的增大响应值变化越来越不明显,因此,固相微萃取装置适用于做痕量分析,该法对于氯苯系化合物的应用范围为：１,２,４－三氯苯、１,２,３,５－四氯苯为０～４０ｕｇ／Ｌ、１,２,３,４－四氯苯、１,２,４,５－四氯苯、五氯苯、六氯苯为０～１０ｕｇ／Ｌ。     

环境中氯苯类化合物的分析研究进展

氯苯类化合物（邻二氯苯、对二氯苯、间二氯苯、三氯苯、氯甲苯、二氯甲苯和三氯甲苯等）是环境中需要重点监测的致癌污染物,文章介绍了近年来国内外环境中氯苯类化合物的分析研究进展。主要的分析测定方法有：普通气相色谱法、固相微萃取．毛细管气相色谱法、吹扫捕集．气相色谱法、顶空气相色谱法、高效液相色谱法、光度法和红外光谱法等。分析测定方法和结果对评价环境污染具有重要意义。     

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。     

新型固相微萃取探头测定工业废水中的甲苯和二甲苯

采用溶胶－凝胶方法研制的聚甲基苯基乙烯基硅氧烷／羟基硅油复合涂层的固相微萃取探头及顶空固相微萃取－气相色谱联用技术（HS－SPME－GC），测定了制漆厂排放的工业废水中的甲苯和二甲苯。研究了影响该方法分析灵敏度的各种条件因素：萃取时间和温度，解吸时间和温度及离子强度等。结果表明新探头性能优于商用聚二甲基硅氧烷探头。方法的检出限为0．01μg/L－0．1μg/L，相对标准偏差小于6％；除苯以外线性范围达3个数量级。     

顶空固相微萃取-气质联用测定环境水样中7种痕量土霉昧物质

建立了同时测定环境水样中7种痕量土霉味物质(2-甲基异冰片、土臭素、2-异丙基-3-甲氧基吡嗪、2-异丁基-3-甲氧基吡嗪、2,3,4-三氯苯甲醚、2,3,6-三氯苯甲醚和2,4,6-三氯苯甲醚)的顶空-固相微萃取气相色谱-质谱联用方法.对顶空-固相微萃取的参数进行了考察与优化,确认了最佳萃取条件:离子强度0.3 g/...     

聚乙烯吡咯啉酮－盐－水液－固萃取体系分离纯化α－淀粉酶的研究

本文研究了α－淀粉酶、酪蛋白、牛血清白蛋白在聚乙烯吡啉酮－盐－水液－固萃取体系中的萃取行为，着重讨论了ｐＨ值、（ＮＨ４）２ＳＯ４浓度及激活剂ＮＳＣ１对酶萃取率的影响。实．验结果表明，在一定条件下，酶大部分被萃入聚合物固相，而杂蛋白则主要分布在盐水相。用该体系分离纯化α－淀粉酶，平均酶活力收得率达９８．９％，一次纯化倍数１．５１。     

固相微萃取技术在形态分析中的应用进展

形态分析比传统的元素分析能提供更为丰富的信息，成为当今分析化学领域前沿课题之一，而固相微萃取（SPME)是近十年来发展起来的新型分离富集技术，简便快速、无污染、易于和其它技术联用．近几年来才开始将固相微萃取应用到形态分析，二者结合对形态分析的发展具有促进作用，本文就固相微萃取技术在元素有机化合物形态分析中的应用进行了评述．     

固相微萃取-气相色谱法分析水中痕量1-萘酚

利用固相微萃取（ＳＰＭＥ）－气相色谱法（ＧＣ）分析了水中前量的１－萘酚。对于ＳＰＭＥ萃取头,溶液介质条件、吸附和解吸时间进行了研究。结果表明,ＰＡ＿８５萃取头对于水中１－萘酚的富集效果最佳。而无机盐氯化钠的加入和降低ＰＨ值可以明显地改善萃取效果。在优化后的条件下,ＳＰＭＥ－ＧＣ方法对于水中１－萘酚的检测限可达０．５μｇ／Ｌ,分析过程中标准偏差均小于４％。     

苯-丙-硅共聚物固相微萃取涂层制备及性能研究

合成了苯乙烯-丙烯酸丁酯-乙烯基三乙氧基硅氧烷三元共聚物,并对其结构进行了表征,对其热稳定性、粘度、与纤维的结合能力等物理性能进行了测试。使用自制固相微萃取装置,研究了该聚合物作为固相微萃取涂层的应用性能,对水中小分子烷基苯、氯苯、硝基苯进行了萃取实验,将萃取结果与商品涂层萃取结果进行了比较,令人满意。实验数据表明,苯-丙-硅三元共聚物作为固相微萃取涂层性能优良。     

新型固相微萃取膜的制备及其在生物检材中毒物提取的应用

用酰胺类化合物和气相色谱固定液制备了一种新型固相微萃取膜,对膜的性质、吸附解吸条件进行了研究;应用该类固相微萃取膜成功地分离了尿液中的吗啡、苯巴比妥以及血液中的敌敌畏,并利用气相色谱-质谱联用技术对分离后的样品进行了分析。     

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.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

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.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

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.     

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.     

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.