多波长线性回归导数分光光度法同时测定饮料中糖精钠和苯甲酸

测定了同时测定两组分的多波多线性回归导数分光光度法,无需进行化学分离。方法用于模拟样品和饮料样品中糖精钠和苯甲酸的同时测定,回收率为９８％￣１０１％,相对标准偏差〈３．０％。     

多波长线性回归紫外分光光度法同时测定复方阿斯匹林片中的三组分

用改进的多波长线性回归分光光度法同时测定了复方阿期匹林片中三组分的含量,模拟样品中阿斯匹林、非那西丁、咖啡因的平均回收率分别为１００．３１％、９９．８７％、１００．７７％,相对标准偏差分别为０．３５％、０．２５％、１．３７％（ｎ＝１０）。对四个批号实际样品的测定结果与标准方法一致,适物复方阿斯匹林片的常规分析。     

偏最小二乘分光光度法同时测定扑热息痛等五组分含量

本文将偏最小二乘分光光度法应用于感冒液中扑热息痛、扑尔敏、咖啡因、对氨基酚和愈创木酚甘油醚五组分含量的分析研究，介绍了基本原理和具体的分析步骤。实验结果表明，偏最小二乘分光光度法对样品各组分的平均回收率在96．4％－105．0％之间，样品不经分离即可同时测定，取得了满意的分析结果。     

大豆磷脂的高效液相色谱分析

采用正相高效液相色谱法,梯度洗脱程序和蒸发光散射检测器对大豆磷脂组成进行分析,在15min内将大豆膦脂中4种重要组分：卵磷脂,脑磷脂,肌醇磷脂和磷脂酸与其它组分完全分离,用外标法对这4种重要成分进行定量,线性范围为0．2－5．8g/L,回收率为96．7－100．8％;相对标准偏差为0．82％－1．34％,方法用于实际样品测定,获得满意的结果。     

比值导数波谱-多波长最小一乘回归分光光度法同时测定饮料中糖精钠、苯甲酸和山梨酸

提出了比值导数波谱－多波长最小一乘回归分光光度法。该法能同时测定三组分混合物而毋需零交点波长和等吸收点，且回归稳健性好．可消除异常点的影响。方法用于合成样品和饮料中糖精钠、苯甲酸和山梨酸的同时测定，相对误差＜± ３． ５％，回收率为 ９６． ６％～１０４．４％，相对标准偏差为２．０％～３．１％．     

汽油中苯的测定

采用高分辨毛细管气相色谱对汽油中的苯进行测定。在汽油样品组分中选定一组分为内标,测定样品后再用内加法添加苯,再次测定,并以两次测定的峰面积数据计算苯量。本文在汽油辛烷值的测定基础上,发展了一种新的汽油中苯量的测定方法：采用国产色谱仪,带内标的内加法即可对汽油中的苯量进行准确测定．在不同标号的汽油测定实验中,相对标准偏差不超过3％。与国标方法相比,该方法简便快速,对仪器设备要求低,提高了分析效率,降低了分析成本,便于推广。     

K系数－多波长最小—乘回归分光光度法同时测定三组分的研究

将双波长Ｋ系数分光光度法和多波长线性回归分光光度法相结合，并采用最小一乘法准则计算回归系数，提出了一种同时测定三组分的新方法，即Ｋ系数－多波长最小一乘回归分光光度法。该法不需要吸收曲线交点和等吸收点，且能较好地克服异常点的影响，得到比最小二乘法更好的回归稳健性。方法用于测定模拟混合色素样品和饮料样品中的柠檬黄、胭脂红、果绿，相对误差为—３．６％～２．８％，回收率为９６．３％～１０４．８％，变异系数小于２．７９％。     

毛细管气相色谱法测定炼厂气中单体烃组分的含量

采用PLOT／Al2O3石英毛细管气相色谱柱和氢火焰离子化检测器，建立了炼厂气中单体烃组分含量测定的毛细管气相色谱法，当炼厂气中单体烃组分的含量大于或等于2．1％时，RSD≤0．95％，当炼厂气中单体烃组分的含量为0．5％－2．1％时，RSD为0．95％－10．0％，当炼厂气中单体烃组分的含量为0．2％－0．5％时，RSD为10．0％－25．0％，该方法对单体烃组分的测定结果与行业标准SH／T0230－92《液化石油气组成测定法》的测定结果基本一致。     

回归正交极谱法测定相互干扰组分锌,钴和镍

分析中干扰组分的分离和掩蔽是麻烦而困难的问题。应用适当的多元正交回归设计可以同时测定相互干扰的几种组分，而不必分离和掩蔽。在乙二胺体系（ｐＨ１２．２）的不同条件下，对相互干扰的组分Ｚｎ，Ｃｏ和Ｎｉ进行回归正交实验研究，得到了极谱电流与组分浓度间的归方程组。通过解此方程组，同时测定了土壤和植物（辣椒）中的Ｚｎ，Ｃｏ和Ｎｉ的含量。结果表明，分析相对标准偏差不大于５．３％，而样品回收率在９５％－１０８％     

汽油中气体组分含量的快速分析

采用美国HP6890炼厂气分析多维填充柱色谱仪,建立了汽油中气体组分含量快速分析方法。采用汽油直接进样,校正归一化法定量,测定汽油中CO2、H2S和各气体烃组分的含量,完成一个样品的分析仅需22min。实验表明,该方法有很好的精密度,各气体组分浓度值的相对标准偏差均小于4．5％。     

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.