Regioselective synthesis of pentasubstituted benzene derivatives: TBAF as an effective catalyst for the sequential Michael addition-intramolecular aldolization

Polysubstituted benzene derivatives were synthesized starting from the Baylis-Hillman adducts via the sequential introduction of primary nitroalkane at the primary position, Michael addition to β-branched Michael acceptor, aldol condensation, elimination of nitrous acid, and the final aromatization process.     

Two-step upflow anaerobic sludge bed system for sewage treatment under subtropical conditions with posttreatment in waste stabilization ponds

A pilot-scale sewage treatment system consisting of two upflow anaerobic sludge bed (UASB) reactors followed by five waste stabilization ponds (WSPs) in series was studied under subtropical conditions. The first UASB reactor started up in only 1 mo (stable operation, high chemical oxygen demand [COD] removal efficiency, low volatile fatty acids concentration in the effluent, alkalinity ratio above 0.7, biogas production above 0.1 Nm3/kg of CODremoved). Removal efficiencies up to 90% were obtained in the anaerobic steps at a hydraulic retention time of 6 + 4 h (80% removal in the first step). Fecal coliform removal in the whole system was 99.9999% (99.94% in anaerobic steps and 99.98% in WSPs). COD balances over UASB reactors are provided. A minimum set of data necessary to build COD balances is proposed. Intermittent sludge washout was detected in the reactors with the COD balances. Sludge washout from single-step UASB reactors should be monitored and minimized in order to ensure constant compliance with discharge standards, especially when no posttreatment is provided. The system combined high COD and fecal coliform removal efficiency with an extremely low effluent concentration, complying with discharge standards, and making it an attractive option for sewage treatment in subtropical regions.     

Determination of Partial Molar Volumes of EPA and DHA Ethyl Esters in Supercritical Carbon Dioxide

The use of supercritical fluids (SCFs) as solvents has been attracting widespread interest in the research and commercial applications. The study of partial molar volumes of solutes at infinite dilution in the near-critical region is of considerable fundamental importance, as these data reflects the interactions occurring between the solute and the solvent. Experimental measurements of partial molar volumes may be divided into two categories: direct and indirect methods. The direct methods…     

Preparation of Europium Induced Conformation—specific anti—calmodulin Monoclonal Antibody

Monoclonal antibody technique was employed to detect the conformational difference of CaM induced by metal ions. A trivalent europium ion induced conformation-specific anti-calmodulin monoclonal antibody was successfully prepared with europium-saturated calmodulin as antigen.     

磷化氢与环烯烃反应的原位^3^1P NMR研究

本文应用加压原位核磁共振波谱技术, 在反应温度50-70℃、反应压力1.0-2.0MPa, 氘代苯为溶剂, 偶氮二异丁腈为引发剂的条件下, 考察了磷化氢与环烯烃1, 5-环辛二烯、双环戊二烯、1, 3-环己二烯、1, 4-环己二烯及1, 5, 9-环十二三烯的反应。实验结果表明, 磷化氢与1, 5-环辛二烯反应主要生成双环膦杂环壬烷; 与其它环烯烃均不生成膦杂环化合物, 仅为一取代伯膦或二取代仲膦产物。磷化氢与环烯烃反应仍为串行机理。     

Zn_2Al－PW_（12－n）V_nO_（40）（n＝1～4）的合成与表征

Ｚｎ_２Ａｌ－ＰＷ_（１２－ｎ）Ｖ_ｎＯ_（４０）（ｎ＝１～４）的合成与表征郭军，孙铁，沈剑平，蒋大振闵恩泽（吉林大学化学系，长春，１３００２３）（石油化工科学研究院）关键词Ｐ－Ｗ－Ｖ杂多阴离子，柱撑水滑石，合成同多和杂多阴离子柱撑水滑石（简称ＰＯＭｓ－...     

Study on the Chromatographic Behavior of Bases on Dodecylamine-N,N-dimethylenephosphonic Acid-Modified Zirconia Stationary Phase

A new zirconia-based stationary phase (DPZ) was prepared by modifying zirconia with dodecylamine-N,N-dimethylenephosphonic acid (DDPA). DDPA was adsorbed on zirconia with only one phosphonic group, with the other being free. Besides the hydrophobic interaction provided by nonpolar dodecyl, DPZ also has dipolar interaction, ion-exchange or electrostatic repellent interaction provided by the free phosphonic group and amino group at different conditions. Separation of bases on this stationary phase was achieved with satisfaction owing to the various retention mechanisms. The influence of methanol content, pH value, ion types, and ionic strength of mobile phase are studied in detail. Translated from Chinese Journal of Chromatography, 2005, 23(1) (in Chinese)     

Acid-catalysed formation of tricyclic N,S-acetals in imidazolinone series based on the use of the unprecedented N-acyliminium ion cascade reaction involving transposition, heterocyclisation and pi-cyclisation

4-Hydroxy-5,5-dimethylimidazolines tethered at N-1 to an aryl sulfide undergo an unprecedented acid-catalysed domino reaction, involving double methyl transposition, heterocyclisation, isomerisation of thiazetidinium ion and, finally, pi-cyclisation. In this way a one-pot synthesis of original tricyclic N,S-acetals was developed. The same triheterocyclic products can be prepared also starting from the corresponding 5-hydroxy isomers (in this case the cascade of reactions does not involve methyl transposition).