测定N—亚硝基化合物的分光光度法

利用Ｎ－亚硝基化合物的化学去亚硝基反应，建立了一种间接测定Ｎ－亚硝基化合物的分光光度法。实验结果表明，Ｎ－二苯基亚硝胺在０．２￣９．０ｍｇ／Ｌ浓度内呈线性关系。该法应用于香烟烟丝及侧流烟雾萃取液的分析，４次测定ＲＳＤ及回收率分别为１．８６％￣６．３２％，８６．２％￣９６．６％；３．０１％￣５．０３％，１０１．１％￣１０９．１％。     

ICP－AES间接法连续测定混合物中的氯和碘离子的研究

本文研究了在Ｃｌ￣－和Ｉ￣－的混合物中，加入过量Ａｇ￣＋使Ｃｌ￣－和Ｉ￣－分别以ＡｇＣｌ和ＡｇＩ沉淀后，用ＩＣＰ－ＡＥＳ测定剩余的Ａｇ￣＋，然后用ＮＨ＿３·Ｈ＿２Ｏ溶解ＡｇＣｌ沉淀，测定溶解液中的Ａｇ￣＋，间接得到Ｃｌ￣－的含量，以差减法求得Ｉ￣－量，实现Ｃｌ￣－和Ｉ￣－的间接法连续测定。本文探讨了有关的化学条件和光谱测定条件，对方法的适用性进行了考察──共存离子的干扰情况，方法的精密度、检出限和试样中加入回收试验。回收率为９７．１％～１０１．２％（Ｃｌ￣－），９８．１％～１００．４％（Ｉ￣－）。     

反相离子对色谱法测定制剂中的舒必利

建立了反相离子对色谱用于测定制剂中舒必利的含量。采用Ｃ８柱，流动相为３５％甲醇－６５％的０．１ｍｏｌ／Ｌ甲酸铵缓冲液（含已烷磺酸钠，ｐＨ＝３．５），检测器ＵＶ２９０ｎｍ，片剂中舒必利平均回收率为９８．８８％￣１００．９２％，样品测试日内及日间ＲＳＤ分别为１．０４％￣２．２９％及１．８５％￣３．０２％。     

二阶导数光度法同时测定微量镍和铜的研究

用２－（２－噻唑偶氮）－５－二甲氨基苯甲酸作为显色剂，在ｐＨ５．６，波长在６２０ｎｍ和５９０ｎｍ处，用于阶导数光度法，同时测定微量镍和铜。回收率镍为１００％￣１０２％，铜在９２％￣１０５％，Ｎｉ＾２＋、Ｃｕ＾２＋在０￣１６μｇ／２５ｍｌ均呈线性关系。     

以新指示反应高敏催化光度测定痕量钌

钌（Ｒｕ￣Ⅲ）对高碘酸钾氧化无色孔雀绿的显色体系有催化作用，借此催化光度测Ｒｕ￣Ⅲ，灵敏度高。在２０～３０℃下３０～６０ｍｉｎ内，以１ｃｍ吸收池内测得吸光度０．１为可准确测极限，则可测最低浓度为０．０８ｎｇ·ｍＬ￣（－１），若表示为间接摩尔吸光系数则 ＝２．０×１０￣８ｍｏｌ￣（－１）·Ｌ·ｃｍ￣（－１）。工作曲线线性范围为０．０４～０．３６ｎｇ／ｍＬ（室温约为２６℃）．其它贵金属如Ｏｓ￣Ⅷ、Ｒｈ￣Ⅲ、Ａｕ￣Ⅲ、Ａｇ￣Ⅰ、Ｐｄ￣Ⅱ、Ｐｔ￣Ⅳ等至少可允许分别存在２００ｎｇ／ｍＬ、１ｎｇ／ｍＬ、２００ｎｇ／ｍＬ、３０００ｎｇ／ｍＬ、２５ｎｇ／ｍＬ和５ｎｇ／ｍＬ。测定了含所有贵金属和某些其它常见金属人工混合液中的痕量Ｒｕ￣Ⅲ，不含Ｉｒ￣Ⅳ时回收率为９８．５％～１０１．０％，含２．３倍于Ｒｕ￣Ⅳ重量的ｌｒ￣Ⅳ时回收率为１０１．５％～１１２％。     

气相法钛系乙烯聚合催化剂的研究：催化剂性质,颗粒形态与…

研究了研磨法（ＣＭ型）和结晶沉淀反应法（ＭＧ－２型）制备的２种乙烯聚合钛系载体催化剂。ＣＭ型催化剂含钛３．４％￣４．０％，三价钛占总钛含量１５％￣２５％，比表面积为１３０ｍ＾２／ｇ，催化剂活性为９．２０ｋｇＰＥ／ｇＴｉ·ｈ聚合反应衰减快。ＭＧ－２型催化剂含钛７．０％￣８．０％，三价钛占总钛含量５５％￣６９％，比表面积为７８ｍ＾２／ｇ，催化活性为４．４５ｋｇ ＰＥ／（ｇ Ｔｉ·ｈ），聚合反应衰减慢，     

毛细管气相色谱法测定牛奶中有机氯和有机磷农药残留量

采用一个较快速、简单的方法测定牛血中有机氯和有机磷农药残留物。牛奶中农残经氯仿萃取和固相提取净化后，分别用气相色谱－电子捕获检测器和气相色谱－火焰光度检测器直接测定，色谱柱为ＨＰ－１接ＨＰ－５、ＤＢ１７大口径石英毛细管柱。本法对１７种有机氯农残的回收效率范围为７１．２％￣９９．７％，检测限为０．５￣９μｇ／ｋｇ。而１１种有机磷农残的回收率范围为７０．１％￣９６．１％，检测限则为０．０１￣０．０４ｍ     

流动注射—结晶紫—磷钼杂多酸离子缔合体系光度法测定水中痕？…

在一定的酸度条件下，结晶紫与磷钼杂多酸离子缔合物的流动注射分光光度法可直接测定痕量磷。灵敏度高，重现性和选择性好。水中常见离子不干扰痕量磷的测定，工作曲线的线性范围为０￣５００μｇ·Ｌ＾－１的磷，检出下限达１．０μｇ·Ｌ＾－１，以１２０ｈ＾－１采样频率，对各种天然水样进行测定，回收率为９２．５％￣１０５．０％，相对标准偏差为０．１％￣６．７％。     

分光光度法测定氯化稀土和轻稀土氧化物中的镨,钕,钐

本文提出在１０％盐酸介质，用紫外－可见分光光度法测定氯化稀土、轻稀土氧化物中的镨、钕、钐，测定波长分别为４４４ｎｍ、５７５ｎｍ、４０１ｎｍ，钐对镨的干扰和镨对钕的干扰均可用校正系数加以消除。方法回收率为９７．５％～１０２．９％，检出下限分别为５０×１０￣（－６）ｇ／ｍＬ，１０×１０￣（－６）ｇ／ｍＬ，１００×１０￣（－６）ｇ／ｍＬ。     

离子交换分离－氢化物原子吸收光谱法测定紫铜中微是量硒

采用阳离子交换树脂离子分离铜，发生氢化物原子吸收光谱法测定硒。上柱溶液酸度在０～７％，硒的回收率在９６～１０１％，过柱溶液中铜的浓度低于０．０１μｇ／ｍＬ。方法检出限为５×１０￣（－５）％，分析紫铜中４．４×１０￣（－４）％的硒，相对标准偏差为３％。     

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%.     

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.     

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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

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.