(R)-4-Menthenone in the synthesis of optically pure sex pheromone of the peach leafminer moth (Lyonetia clerkella)

The synthesis of (14S)-methyloctadec-1-ene, sex pheromone of the peach leafminer moth (Lyonetia clerkella), is described to demonstrate a new potential of the synthetic use of (R)-4-menthenone.     

Selective Oxidation of Isobutene over CsFeCoBiMnMoOx Mixed Oxide Catalyst

Mixed oxide catalyst Cs0.1Fe2Co6BiMnMo12Ox was prepared by the coprecipitation method.Selective oxidation of isobutene was carried out in a fixed-bed reactor over Cs0.1Fe2Co6BiMnMo12Ox.The results showed that the catalyst had high catalytic activity. Under the optimum reaction conditions(n(i-C4):n(O2)=1:2-1:4, space velocity=180 h^-1, T=360℃), the yields of methacrolein and methacrylic acid can reach 80% and 8%, respectively. The total yield of liquid products (methacrolein, methacrylic acid and acetic acid) can reach about 90%.     

Characterization of Carbon Film Electrodes for Electroanalysis by Electrochemical Impedance

The interfacial behavior of electrodes fabricated from carbon film resistors of 2 and 20 Ω in supporting electrolyte solutions of varying pH used in electroanalytical experiments has been characterized by electrochemical impedance spectroscopy with complementary cyclic voltammetric experiments. Equivalent circuits are proposed to fit the experimental data and the influence of electrode pretreatment has also been investigated.     

TiO2光催化反应及其在环境保护中的应用

本文简要介绍了TiO2光催化剂的作用机理，讨论了影响TiO2光催化效率的因素及解决途径，综述了光催化在环境保护中的最新应用。     

Complete Oxidation of Methane over Palladium Supported on Alumina Modified with Calcium,Lanthanum,and Cerium Ions

The activity and thermal stability of Pd/Al_2O_3 and Pd/(Al_2O_3 MO_x)(M=Ca,La,Ce) palladium catalysts in the reaction of complete oxidation of methane are presented in this study.The catalyst supports were prepared by sol-gel method and they were dried either conventionally or with supercritical carbon dioxide.Then they were impregnated with palladium nitrate solution.The catalysts with unmodified alumina had a high surface area.The activity and thermal stability of the alumina- supported catalyst was also very high.The introduction of calcium,lanthanum,or cerium oxide into alumina support caused a decrease of the surface area in the way dependent on the support precursor drying method.These modifiers decreased the activity of palladium catalysts,and they required higher temperatures for the complete oxidation of methane than unmodified Pd/Al_2O_3.The improvement of the palladium activity by lanthanum and cerium support modifier was observed only at low temperatures of the reaction.     

Kinetic Analysis of the Mechanism of Oxidation of CO on Co/ZSM-5

We have studied the kinetic behavior of oxidation of carbon monoxide on Co-containing zeolite ZSM-5. We have shown that the kinetic curves obtained for the dependence of the reaction rate on the reagent concentration can be described by an Eley–Rideal mechanism, which assumes that oxygen can be adsorbed on the surface of the catalyst in both atomic and molecular form, followed by reaction of CO from the gas phase with the adsorbed oxygen.     

丙烯选择氧化铋钼铁复氧化物催化剂组成,结构及性能的研究

采用XRD、Raman、XPS及催化剂性能评价等手段,考察了Bi_3(FeO_4)(MoO_4)_2和Fe_2(MoO_4)_3分别存在及两者共存时对Bi-Mo复氧化物体系催化性能的影响.结果表明,这两种含Fe物种的存在都有助于改善Bi-Mo系复氧化物催化剂对丙烯选择氧化反应的催化性能.但两者在作用机理上有所不同.Fe_2(MoO_4)_3本身无催化活性,但在反应条件下可部分还原为FeMoO_4形成Fe~(3+)/Fe~(2+)氧化还原对;且其地结构上与α-Bi_2(MoO_4)_3相匹配,这些因素都有助于促进催化体系中电子和氧物种的传递及催化剂表面活性中心的再生,从而提高催化性能.Bi_3(FeO_4)(MoO_4)_2在反应条件下也可形成Fe~(3+)/Fe~(2+)氧化还原对,但由于其Fe~(3-)所处的化学环境与Fe_2(MoO_4)_3很不相同,且Fe的含量也不及Fe_2(MoO_4)_3,因此它在促进催化体系中电子和氧物种的传递及催化剂表面活性中心的再生等方面的性能较差,但它对提高催化剂表面的活性中心(Bi-Mo对)数目有贡献.     

Determination of cake thickness and porosity during cross-flow ultrafiltration on a plane ceramic membrane surface using an electrochemical method

The thickness and the porosity of a deposit during ultrafiltration experiments are determined using an electrochemical method. Twenty microelectrodes are mounted flush to a ceramic plane membrane and maps of deposit thickness are determined for three inlet/outlet distributors configurations. Combining an electrochemical method and a step transient method, the determination of the thickness and the porosity of a particles deposit is performed. These local thickness and porosity values are analyzed thanks to wall shear stress local measurements obtained in a previous work [Sep. Sci. Technol. 37 (10) (2002) 2251]. The results emphasize the heterogeneity of the deposit thickness, especially in zones of low wall shear stress. Furthermore, the porosity values of the deposit are ranged between 0.3 and 0.8 as a function of the location at the membrane surface.     

Solvothermal Synthesis, Crystal Structure and Electrochemical Property of Complex [Co(p-MBA)2(2,2''-bipy)(H2O)]·(H2O)

One novel complex [Co(p-MBA)2(2,2'-bipy)(H2O)]·(H2O) has been synthesized by the reaction of p-methylbenzoic acid with 2,2'-bipyridine in the solvent mixture of water and methanol. It crystallizes in triclinic, space group P-1 with a=0.70479(14), b=1.1211(2), c=1.6718(3) nm, α=103.806(3), β=90.795(3), γ=104.207(3)°, V=1.2399(4) nm3, Mr=512.41, Dc=1.373 g/cm3, Z=2, F(000)=532, μ=0.733 mm-1, R=0.0432 and wR=0.0957. The crystal structural analysis shows that the cobalt atom is coordinated with three oxygen atoms from two p-methylbenzoic acids and one water molecule and two nitrogen atoms from one 2,2'-bipyridine,forming a distorted square-pyramidal coordination geometry. The cyclic voltammetry behavior of the complex is also reported.     

Photoinduced electron transport process in electrochemical cell I. Phenomenological description

The process of electron transport plays an essential role in the fundamental phenomena of life like photosynthesis, respiration and vision as well as in photoelectronic devices. However, the molecular mechanisms of the electron way and factors governing the transport rate in such systems are still unclear. Several groups have reported theoretical approaches for searching the mechanisms by using statistical mechanics, coherent dynamics and quantum mechanics. The current density vector inside the semiconducting layer is determined. In this paper we consider the problem of transport of electron promoted in the electrochemical cell constructed of two electrodes with the dye molecules immersed in. We describe the process of electron promotion by refractive light wave on the vacuum–semiconductor boundary as well as on the semiconducting electrode and the dye molecule layer in terms of extended phenomenological electrodynamics formalism. The results of our theoretical model show that such a theoretical approach will give more information on the mechanism of electron transport and will give insight in the determination of some electric features of materials.