Study of direction of cyclization of malonodithioamides as a method of investigation of reactivity of α-diazothioacetamides

The reaction of malonothioamides with benzene-sulfonyl azide and 2-azido-3-ethylbenzthiazolium tetrafluoroborate gave amides of 2-diazothiomalonic acid, which underwent cyclization to a mixture of 5-N-R-amino-1,2,3-thiadiazole-4-carbothioamides and 5-amino-1,2,3-thiadiazole-4-N-R-carbothioamides. The ratio of the isomeric thiadiazoles formed in this reaction is the same as in the reactions of 2-diazo-2-cyanoacetamides, 5-amino-1,2,3-thiadiazole- and 5-mercapto-1,2,3-triazole-4-carboxamides with P₄S₁₀ and of 5-amino-1, 2,3-thiadiazole-4-carbonitriles with H₂S; it is characteristic of the influence of substituents on the reactivity of -diazothioacetamides. It was found that the cyclization of the diazo compounds is accelerated when electron-acceptor substituents are attached to the nitrogen atom of the carbothioamide group.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1106–1112, August, 1992.     

Structure of Potassium of Undecatungstomononickelosilicate

ＳｔｒｕｃｔｕｒｅｏｆＰｏｔａｓｓｉｕｍｏｆＵｎｄｅｃａｔｕｎｇｓｔｏｍｏｎｏｎｉｃｋｅｌｏｓｉｌｉｃａｔｅＱｕＬｕｎ－Ｙｕ；ＭａＲｏｎｇ－Ｈｕａ；ＣｈｅｎＹａ－Ｇｕａｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ，ＮｏｒｔｈｅａｓｔＮｏｒｍａｌＵ...     

Synthesis of Related Compounds of Carotenoid

类胡萝卜素是一类奇特的色素，由高等植物和微生物光化学合成，作为防止单线氧通过光敏反应产生危害的必要基团，类胡萝卜素最近受到了关注。类胡萝卜素联于富勒烯上，既可大大增加在可见光区域光诱导电子转移的有效吸收断面，又可抑制富勒烯敏化单线氧的危害能力。合成了类胡萝卜素的相关化合物，报道的某些反应条件先进且简洁。     

Analysis of Significance of Unite Examination of AFP and DNA Polymorphism of P3 Promoter of IGF-ⅡGene

The DNA of P3 promoter region of IGF-Ⅱ gene was obtained by means of PCR technique. The examination of DNA polymorphism by restriction endonuclease BstE Ⅱ and the examination of AFP by bioluminescence immunoassay technique were carried out. The results have a significant difference(P<0.005). But the positive rate of AFP is higher than that of DNA polymorphism. The experimental result shows that the change of the DNA polymorphism of IGF-Ⅱis not the only carcinogenic factor. The suggested unite examination is the best method for the diagnosis of the primary hepatocellular carcinoma.     

Synthesis of a Pair of Derivatives of N-Methylpyrrole Polyamide

A pair of derivatives of tetrameric N-methylpyrrole polyamide were synthesized in order to develop a new method for the study of interaction of the polyamide derivatives with DNA. Indole acetic acid and nicotinic acid were introduced to the polyamide in the synthesized compound, which showed an expected red shift in the UV spectrum. These compounds may function as a potential tool in the detection of the polyamide binding to DNA.     

Structure determination of glycopeptide of β-momorcharin

The structure of the N-linked oligosaccharide chain of β-momorcharin, a ribosome-inactivating protein from the seeds of Momordica charantia Linn (Cucurbitaceae), was determined. A glycopeptide liberated by pronase digestion of the glycoprotein was subjected to amino acid and neutral carbohydrate analysis to establish the composition of amino acid and sugar residues. The sequences and glycosylation hnkages of the sugar and amino acid residues in the glycopeptide were determined as Manαl-6(XyIβ1-2)-Manβ1-4GlcNAcβ1-4(Fucαl-3)-GlcNAc-Asn-Leu by 2D-NMR spectroscopy and FAB-MS data.     

Analysis of Significance of Unite Examination of AFP and DNA Polymorphism of P3 Promoter of IGF- Ⅱ Gene

IntroductionTheinnatecharacterofthesolidcarcinomaistheresultthatcellgrowthgetsoutofcontrol.Itsbasicreasonconsistsintheabnormalityofthetumorgene .SomeonethinksthatthegeneofIGF Ⅱisoneofthecancergenesofthe primaryhepatocellularcarcino ma[1] ,andalsothinkstheoverexpressionofthegeneofIGF Ⅱtakesplaceintheearlierperiodofthepri maryhepatocellularcarcinoma ,whichmaybetheear lierdiagnosticnormofprimaryhepatocellularcarcino ma .ThefurtherresearcheshavedemonstratedthattheactivationofIGF Ⅱ genepromo…     

Kinetics of tautomerization of 1,3,4,7-tetramethylisoindole

The kinetics of transformation of 1,3,4,7-tetramethylisoindole(1)to 1,3,4,7-tetramethyl-1H-isoindole(2)in water or in deuterium oxide at various pH or pD at 25℃ were measuredspectrophotometricalty.The results indicated that the transformation of 1 to 2 could be promotedby acid and base.From the solvent isotope effects and the fact that the 1-position of isoindole nucleusis electron-rich,the mechanism of this transformation is suggested.     

Analysis of Chemical Incredients of Angelica Sinnesis——Analysis of Non-Volatile Constituents of Roots

In the present investigation,the non-volatile constituents of Danguei (Tang-Kuei) roots of Gansu origin [Angelica sinensis (Oliv.) Diels] were analyzed and thirty seven organic constituin s were also identified,fifteen of which have not been recorded in literature before,including a new optically active compound named as Angelicide and an antibiotie,Brereldin A.By plasma emission spectrometry,thirteen minor elements were also detecled     

TPSR Studies of the Activation of

TPSR　Studies　of　the　Activation　of　...     

Low CO content hydrogen production from oxidative steam reforming of ethanol over CuO-CeO2 catalysts at low-temperature

CuO-CeO₂ catalysts were prepared by a urea precipitation method for the oxidative steam reforming of ethanol at low-temperature. The catalytic performance was evaluated and the catalysts were characterized by inductively coupled plasma atomic emission spectroscopy, X-ray diffraction, temperature-programmed reduction, field emission scanning electron microscopy and thermo-gravimetric analysis. Over CuO-CeO₂ catalysts, H₂ with low CO content was produced in the whole tested temperature range of 250–450 °C. The non-noble metal catalyst 20CuCe showed higher H₂ production rate than 1%/oRh/CeO₂ catalyst at 300–400 °C and the advantage was more obvious after 20 h testing at 400 °C. These results further confirmed that CuO-CeO₂ catalysts may be suitable candidates for low temperature hydrogen production from ethanol.     

(CuO-CeO2)/glass cloth catalysts for selective CO oxidation in the presence of H2: The effect of the nature of the fuel component used in their surface self-propagating high-temperature synthesis on their properties

The potential of surface self-propagating high-temperature synthesis (SSHS) for obtaining (CuO-CeO₂)/glass cloth catalysts is demonstrated. The dependence of the structural and catalytic properties of the catalysts on their preparation conditions (nature of the fuel component) is considered. X-ray diffraction, electron microscopy, and EXAFS data suggest that the short-term action of high temperature in the SSHS leads to the complete decomposition of the precursors and has an effect on the distribution of the resulting phases. According to H₂ TPR and XPS data, the degree of dispersion of CuO and the electronic state of the reacting CuO and CeO₂ phases depend on the choice of fuel. This is likely due to fuels varying in the amount of heat released in their combustion. The degree of dispersion of CuO and the total contribution from Cu¹⁺ and Ce⁴⁺ to the electronic state of the active component increase as the standard enthalpy of combustion increases in the urea < glycerol < citric acid order. This leads to an increase in the catalytic activity of the (CuO-CeO₂)/glass cloth system in selective CO oxidation.     

负载型P-Mo-V/SBA-15催化剂上的甲烷选择氧化反应

以磷钼钒杂多酸(H₅PMo₁₀V₂O₄₀)为前驱体、介孔SBA-15为载体, 采用浸渍法制备不同负载量的P-Mo-V氧化物催化剂. 在甲烷选择氧化反应中, 考察了负载量、反应温度、空速等对甲烷转化率和产物选择性的影响. 结果表明, 催化剂对甲烷选择氧化制甲醛具有较高活性, 甲烷转化率随负载量的增大和反应温度的升高而提高, 甲醛的选择性随负载量的增大先升后降. 反应温度为640 ℃、空速为48300 L•kg^－1•h^－1、氧化物负载量w＝2.89%时, 甲醛的时空产率最高(295 g•kg_cat^－1•h^－1). 多种表征表明, 氧化物负载量w≤2.89%时, P-Mo-V氧化物在载体介孔孔道内以高分散形式存在. 催化剂的酸性和氧化还原性质与负载量相关, NH₃-TPD和H₂-TPR的测试结果表明, 较弱的酸性位和较低还原温度的活性组分有利于甲烷选择氧化制甲醛.     

负载型铜基催化剂组分间相互作用及其催化性能

负载型铜基催化剂因其良好的催化性能和相对低廉的价格在诸多重要工业催化反应中得到广泛的应用.探讨负载型铜基催化剂中组分间的相互作用,有助于了解相关催化作用的本质,为现有催化剂的改进和新催化剂的设计提供科学依据.本文综述了近年来我们就CuO在不同载体上的分散、铜物种和载体的改性及其物理化学性质以及催化CO完全氧化、CO+NO和NH₃+NO+O₂反应性能等方面的研究进展.结果表明,CuO在多种氧化物载体表面的分散和所得负载型铜基催化剂的一些物理化学性质可参考“嵌入模型”得到解释,本文主要讨论了以CeO₂,Ce_xZr_1-xO₂和Mo₃-CeO₂为载体的一些铜基催化剂的组成-结构-性质间的关系.     

Promotion effect of adsorbed water/OH on the catalytic performance of Ag/activated carbon catalysts for CO preferential oxidation in excess H2

Activated carbon (AC) supported silver catalysts were prepared by incipient wetness impregnation method and their catalytic performance for CO preferential oxidation (PROX) in excess H₂ was evaluated. Ag/AC catalysts, after reduction in H₂ at low temperatures (≤200 °C) following heat treatment in He at 200 °C (He200H200), exhibited the best catalytic properties. Temperature-programmed desorption (TPD), X-ray diffraction (XRD) and temperature-programmed reduction (TPR) results indicated that silver oxides were produced during heat treatment in He at 200 °C which were reduced to metal silver nanoparticles in H₂ at low temperatures (≤200 °C), simultaneously generating the adsorbed water/OH. CO conversion was enhanced 40% after water treatment following heat treatment in He at 600 °C. These results imply that the metal silver nanoparticles are the active species and the adsorbed water/OH has noticeable promotion effects on CO oxidation. However, the promotion effect is still limited compared to gold catalysts under the similar conditions, which may be the reason of low selectivity to CO oxidation in PROX over silver catalysts. The reported Ag/AC-S-He catalyst after He200H₂00 treatment displayed similar PROX of CO reaction properties to Ag/SiO₂. This means that Ag/AC catalyst is also an efficient low-temperature CO oxidation catalyst.     

Alumina-supported cobalt phosphide as a new catalyst for preferential CO oxidation at high temperatures

Abstract

Novel alumina-supported cobalt phosphide catalysts (designated as CoP-3, CoP-10, CoP-20 and CoP-40) prepared from the precursors with Co loadings of 3, 10, 20 and 40?wt% by H₂-temperature-programmed reaction were investigated as potential catalysts for preferential CO oxidation (PROX) in excess H₂ at high temperatures. It was found that the catalytic activities of these Co₂P/γ-Al₂O₃ catalysts were related to their Co loadings. The CoP-10 catalyst showed the best PROX performance in temperature range of 220–240?°C, which was attributed to its optimal microstructures (high surface area, small particle size and big amount of active site).     

固相浸渍法制备NiO/CeO2催化剂及其在CO氧化反应中的应用

采用固相浸渍法制备了一系列NiO/CeO2催化剂,并通过与常规湿浸渍法比较,考察了制备方法对催化剂和CO氧化反应性能的影响.同时结合X射线衍射(XRD),N2吸附-脱附(BET),透射电镜(TEM),氢气-程序升温还原(H2-TPR),拉曼(Raman)光谱,X射线光电子能谱(XPS)等手段对催化剂的结构和表面物种分散状态进行了表征.CO氧化活性测试结果表明,当镍负载量相同时,固相浸渍法制备的催化剂相比于湿浸渍法表现出更好的催化性能.TEM、XPS、H2-TPR结果表明,固相浸渍法更有利于加强镍铈间的相互作用和得到高分散的镍物种,从而促进镍物种的还原.Raman结果表明固相浸渍法相比于湿浸渍法能产生更多氧空位,这有利于氧气在催化剂表面的活化,使得CO氧化反应更容易进行.     

Ni/Fe物质的量的比对Ni-Fe催化剂表面性质和二硝基甲苯加氢活性的影响

采用Fe粉置换氯化镍溶液中的Ni²⁺制备了Ni-Fe催化剂, 并应用于催化二硝基甲苯加氢合成甲苯二胺的反应中。运用XRD、低温氮吸附-脱附、H₂-TPD、XPS和TEM等技术手段对不同Ni/Fe物质的量的比(n_Ni/n_Fe)下催化剂进行了表征。结果表明, n_Ni/n_Fe对Ni-Fe催化剂表面性质影响显著。当n_Ni/n_Fe为1:4时, Fe抑制Ni氧化的作用达到最大, Ni-Fe催化剂化学氢吸附量和活性物种Ni的分散度分别达到了0.16 mmol·g^-1和23%, 催化剂性能得到较大的提升。在优化的催化剂制备条件下, DNT(二硝基甲苯)的转化率和TDA(甲苯二胺)的选择性分别达到了~100%和99%。另外, 对Ni-Zn漆原镍(Urushibara Ni)催化剂和Ni-Fe催化剂催化DNT加氢反应进程进行了研究, 发现它们有相同的加氢中间产物, 但反应不同阶段的催化速率存在差异。     

Mesoporous Mn promoted Co3O4 oxides as an efficient and stable catalyst for low temperature oxidation of CO

Mesoporous Mn-doped Co₃O₄ catalysts were successfully prepared via a dry soft reactive grinding method based on solid state reaction, and their catalytic performances on CO oxidation were evaluated at a high space velocity of 49,500 mL g⁻¹ h⁻¹. A significant promoted effect was observed once the atomic ratios of Mn/(Co+Mn) were lower than 10%, for instance, the temperature for 50% conversion decreased to about −60 °C, showing superior catalytic performance compared to the single metal oxide. Especially, the Mn-promoted Co₃O₄ catalyst with a Mn/(Co+Mn) molar ratio of 10% could convert 100% CO after 3000 min of time-on-steam without any deactivation at room temperature. As prepared catalysts were characterized by XRD, N₂-adsorption/desorption, TEM, H₂-TPR, O₂-TPD and CO-titration analysis. The significant enhancement of performance for oxidation of CO over Mn-Co-O mixed oxides was associated with the high active oxygen species concentrations formed during the pretreatment in O₂ atmosphere.     

介孔氧化铝负载Ni-Co氧化物催化剂上丙烷氧化脱氢制丙烯

以非离子型三嵌段共聚物作为模板剂, 异丙醇铝为氧化铝的前驱物, 采用一锅法合成了一系列介孔氧化铝负载镍氧化物、钴氧化物以及镍-钴双金属氧化物催化剂, 并以介孔氧化铝为载体, 采用浸渍法制备了负载Ni-Co 氧化物催化剂. 采用N₂吸附-脱附、高分辨透射电镜(HRTEM)、X射线粉末衍射(XRD)、H₂程序升温还原(H₂-TPR)以及激光拉曼光谱(LRS)等技术对催化剂的结构与性质进行表征, 并考察了催化剂的丙烷氧化脱氢反应性能. 结果表明: 一锅法制备的各催化剂均有大的比表面积和规整的孔道结构, 且负载的金属氧化物高度分散; 而浸渍法制备的催化剂, 其载体的介孔结构被破坏并有Co₃O₄晶相生成. 在考察的催化剂中, 一锅法合成的介孔氧化铝负载Ni-Co 氧化物催化剂表现出最佳的丙烷氧化脱氢性能. 在450 °C、C₃H₈:O₂:N₂的摩尔比为1:1:4和空速(GHSV)为10000 mL·g^-1·h^-1条件下, 该催化剂上丙烯产率为10.3%, 远高于浸渍法制备的催化剂上所获得的丙烯产率(2.4%). 关联催化剂表征和反应结果, 讨论了催化剂结构与性能之间的关系.