土壤中多种有机氯及拟除虫菊酯类农药的GC-ECD测定

气相色谱法同时测定土壤中多种有机氯及拟除虫菊酯类农药。对土壤的分析结果：有机氯农药的检出限0．001～0、003μg／mL，拟除虫菊酯类农药检出限0.008～0．02μg／mL，线性相关系数0．9978～0．9999。用y（石油醚）：V（丙酮）=3：1超声波提取，有机氯农药回收率94．2％～124．0％，相对标准偏差为3．3％～8．8％（n=5）；拟除虫菊酯类农药回收率95．2％～118．3％，相对标准偏差为5．7％～7．1％（n=5）；方法适用于土壤样品中农药残留测定。     

气相色谱-质谱法快速筛选测定浓缩苹果汁中105种农药残留量

采用硅藻土柱层析法对样品中的农药进行提取及净化后，用气相色谱—质谱法在选择离子监测模式下进行快速测定，以保留时间和特征离子定性定量；采用此方法测定了包括有机氯农药、有机磷农药、氨基甲酸酯农药、拟除虫菊酯农药、三嗪类农药在内的105种农药，大多数农药的线性范围为0.05～10mg／kg，相关系数大于0.99；90％以上农药在0．2mg／kg添加水平的平均回收率在70％～110％的范围内。     

基质固相分散-加速溶剂萃取-气相色谱法测土壤中有机氯农药残留

建立了用弗罗里硅土作基质固相分散剂的加速溶剂萃取、并以灭蚁灵（Mirex）为内标的快速、同时测定土壤中16种有机氯农药的气相色谱法。加速溶剂萃取仪在100℃,10．3Mpa用正己烷和丙酮（1：1,V／V）静态提取样品10min,0．01μg/g加标水平回收率为77．3％-101．3％;方法检出限为0．01—0．04ng／g。方法满足了土壤中有机氯农药残留测定的要求。对我国南方不同地域的72个土壤样品进行了测定,大部分有机氯农药在土壤中都有一定检出量,其中环氧七氯最高（2．6～844．5ng／g）,甲氧DDT（23．2—219．8ng／g）和P,P’-DDT（4．0—183．1ng／g）次之,而o,P＇-DDT在72个土样中都没有检出。     

毛细管气相色谱法测定水果、蔬菜中17种有机氯农药的残留量

采用毛细管气相色谱法测定水果、蔬菜中17种有机氯农药的残留量。用丙酮-正己烷混合液(1：1)提取样品中的有机氯农药,将提取液浓缩后,经过弗罗里硅土层析柱净化,用HP-5毛细管柱分离,再以电子捕获检测器测定,外标法定量。方法的加标回收率为80．7％-113．1％,测定结果的相对标准偏差为9％-17％,检出限为0．5—8．0ng／g。     

加压溶剂萃取-气相色谱法测定养麦中残留的有机氯农药

用所研制的24位全自动加压溶剂萃取仪（APLE）,以丙酮-正己烷（体积比为1：1）为溶剂,在100℃和10MPa条件下,对荞麦样品中残留的7种有机氯农药进行了萃取,并通过气相色谱对萃取液进行定量分析。萃取的绝对回收率为68％～126％．相对标准偏差为1．2％～14．7％,检测下限为0．051～0．18ng／g。与索氏提取法对比,相对提取回收率为116％～148％,表明萃取收率高于索氏提取法。     

中草药中有机氯农药和拟除虫菊酯农药残留量的测定

建立了中草药中11种有机氯农药和8种拟除虫菊酯农药的残留气相色谱分析方法。样品用含30％丙酮的乙腈提取,用正己烷进行液液分配,提取液用弗罗里硅土柱净化,采用兰州化物所的农残Ⅱ号毛细管柱分离,用GC-ECD同时检测。在两个水平添加时的回收率(n=5)分别为78．6％～119．7％和86．5％～114．0％,相对标准偏差分别为3．6％～8．7％和4．4％～10．2％。该方法的检出限为：有机氯农药0．005mg／kg,拟除虫菊酯农药0．01mg／kg。方法用于江西中草药样品中农药残留测定,结果满意。     

大口径毛细管气相色谱法测定油脂、果蔬中20种有机氯农药的残留量

 对水果、蔬菜样品采用混合溶剂提取 ,对油脂样品则采用乙腈分配处理 ,然后运用柱色谱净化方式 ,以HP 1 0 1大口径弹性石英毛细管柱为分离柱 ,以电子捕获检测器检测 ,用气相色谱法测定油脂、水果、蔬菜中 2 0种有机氯农药的残留量。方法的检测限为 1 .0ng/g～ 2 0 .0ng/g ,回收率为 83.2 %～ 1 0 6.8% ,RSD为 2 .0 %～9.5%。     

气相色谱质谱联用法对农产品中8种种衣剂农药残留的同时测定

应用气相色谱-质谱联用仪（GC-MS）建立了水果、蔬菜、粮谷等农产品中8种种衣剂农药残留的分析测定方法。样品用乙腈提取,通过石墨化碳或C18固相萃取小柱净化,经DB-5ms气相色谱柱分离,电子轰击电离（EI）、选择离子监测模式（SIM）对定量离子和定性离子进行MS测定。标准工作曲线范围0．02-0．5mg／L。样品中添加水平为0．005、0．010和0．020mg／kg时,回收率为74％～110％;相对标准偏差小于15％。检出限（S／N=3）为0．09～0．77μg／kg。     

毛细管气相色谱法测定中药材中多种拟除虫菊酯农药残留量

研究了气相色谱法测定中药材中多种拟除虫菊酯类残留量的分析方法。样品经正己烷．丙酮混合液[V（正己烷）：V（丙酮）=1：1]提取,氟罗里硅土层析柱净化,采用毛细管色谱柱分离,GC-ECD可同时测定8种拟除虫菊酯类农药残留量,回收率为76．6％～104．2％。     

大口径毛细管气相色谱法测定果蔬中15种有机氯农药残留量

果蔬样品中１５种有机氯农残用丙酮－石油醚提取,经含５％Ｈ２Ｏ的浓硫酸磺化离心净化,ＧＣ－ＥＣＤ测定。色谱柱为ＨＰ－５０＋大口径毛细管柱,方法的回收率为８５．７～１０８．５％,变异系数４．８～１２．６％。     

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.