Influence of the activation temperature on structural and textural properties of NiMo/Al2O3 hydrodesulfurization catalysts

Investigations of a commercial NiMo/Al₂O₃ hydrodesulfurization (HDS) catalyst are directed towards optimization of the activation procedure of HDS catalyst concerning active phase formation and thermal stability. Structural and textural data obtained with XRD, IR-FTIR, XPS and LTNA reveal that the optimal temperature for the formation of active species on the catalyst surface and an appropriate pore structure is 300°C.     

在离子液体中一步法合成吡唑[5,4-b]-γ-吡喃衍生物

芳醛、丙二腈与4,5-二氢-3-甲基-5-氧代-1-苯基吡唑在离子液体[bmim][BF₄]中反应, 合成了2-氨基-4-芳基-3-氰基-5-甲基-7-苯基吡唑[5,4-b]-γ-吡喃衍生物, 该法快速、高效, 是一种洁净的合成方法. 产物的结构通过红外光谱、核磁共振氢谱和元素分析进行表征.     

Solubility enhancement of triflumizole by host-guest interaction with β-cyclodextrin

Summary The solubility enhancement of triflumizole, a systemic fungicide, by -cyclodextrin inclusion complexation was investigated by electron absorption spectroscopy. The respective association constant determined by different methods was estimated to 470±20M ^–1 in aqueous solution. A model for the host-guest complexation was deduced by molecular calculations.

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Löslichkeitsverbesserung von Triflumizole durchHost-Guest-Complexierung mit -Cyclodextrin

Zusammenfassung Die Löslichkeitsverbesserung des systemischen Fungizids Triflumizole durch Komplexierung mit -Cyclodextrin wurde mittels Elektronenabsorptionsspektroskopie untersucht. Die entsprechende Stabilitätskonstante wurde durch verschiedene Methoden erfaßt und betrug im wäßrigen Medium 470±20M ^–1. Ein Model für denHost-Guest-Complex wurde durch Molekülrechnungen erstellt.

     

4-甲氧基-2,3,5-三甲基吡啶的合成新方法

以2，3，5-三甲基吡啶为原料，经氧化，硝化，甲氧基化，脱离四步反应合成 4-甲氧基-2，3，5-三甲基吡啶，总收率76%，其结构经IR，~1H NMR，~(13)C NMR 确证。     

A Minor New Flavone from Scutellaria baicalensis Georgi

A new flavone,6,2′-dihydroxy-5,7,8,6′-tetramethoxyflavone,was isolated from the roots of Scutellaria baicalensis. Its structure was established on the basis of spectral evidences.     

Interaction of aryldiazonium salts with some schiff-base complexes of cobalt and ruthenium

The interaction of aryldiazonium ions with some Schiff-base complexes of cobalt and ruthenium have been studied. With cobalt, one-electron oxidation of [Co(II)Salen] occurred; with [Co(I)Salen] the corresponding Co(III)-aryl complexes were isolated. In the case of ruthenium oxidation also occurs, [Ru(Salen)(CO)py] gave the corresponding monocation. The results, especially for ruthenium, are in contrast to the stabilisation of both nitrosyl and aryldiazonium adducts in analogous porphyrin complexes.     

纳米CeO2的形貌控制与表征

以Ce(NO3)3·6H2O和(NH4)2CO3为沉淀源,利用柠檬酸作为络合剂和分散剂,实现了对CeO2前驱体的形貌和尺寸控制,并采用TEM,TGA和XRD等方法对前驱体及其热分解所得纳米CeO2的形貌及结晶性等进行了表征.结果表明,随着柠檬酸加入量的提高,前驱体形貌从纳米线向类球形颗粒变化,焙烧生成的纳米CeO2颗粒的形貌具有明显继承性,所得CeO2属于立方萤石结构,且随焙烧温度的提高,晶化程度增大.     

Multipole expansion of diatomic overlap

A systematic extension of Ruedenberg's expansion formula is applied to evaluate two-electron integrals occurring in calculations on molecular structure. Minimum STO basis sets are used for all SCF-calculations within the framework of the MEDO-method (Multipole Expansion of Diatomic Overlap). The errors due to this approximation scheme are almost negligible compared to those introduced by the truncated basis set: LiH, Li₂ and N₂ are chosen as examples.     

Non-empirical LCAO-MO-SCF calculations of the electronic structure of SiF2

Non-empirical LCAO-MO-SCF calculations on SiF₂ using two Gaussian basis sets are reported. The larger basis set gives a calculated geometry in good agreement with experiment. The effect on the energy and population analysis of optimization of the Si 3d exponent was investigated. 3d orbitals are found to be much less important in the bonding than in the isoelectronic molecule SO₂.     

Phase equilibria in the ternary system PbO−P2O5−PbCl2

Journal of Thermal Analysis and Calorimetry - In the ternary system PbO?P2O5?PbCl2, the partial ternary system Pb5Cl2O4?Pb3Cl2O2?Pb10(PO4)6Cl2 was examined by thermal,...