An Efficient and Green Synthesis of 5-Oxo-5, 6, 7, 8-tetrahydro- 4H-benzo-[b]-pyran Derivatives Promoted by InCl_3·4H_2O Under Microwave Irradiation

Construction of tetrahydropyran rings has attracted a great deal of interests in organic synthesis in recent years1, since tetrahydropyran moiety constitutes a structural unit in a number of natural products2. In addition, tetrahydropyran derivatives possess wide range of biological activities and pharmacological properties, such as anticancer activity3 and antihypersensitivity4. Many methods for the preparation of such compounds have already been developed5. Among them, condensation of α, β…     

预处理条件对Zn/Al-CLM的丙烷芳构化性能的影响

在脉冲微反装置上考察了不同的预处理条件对Zn/Al-CLM催化剂的丙烷芳构化反应的影响。结果表明，丙烷在Zn/Al-CLM催化剂上具有一定的的反应活性和芳烃选择性，而且芳构化主要转化为苯；载体Al-CLM的焙烧温度、金属锌负载量、活化温度等对Zn/Al-CLM催化剂的丙烷芳构化性能具有重要影响。载体经500℃预焙烧制备的Zn/Al-CLM催化剂具有最好的柱结构保留度，从而表现出最佳的芳构化性能；随着锌含量的增加，Zn/Al-CLM催化剂的酸量增大，从而使丙烷转化率增大，而选择性则是锌含量质量分数为5．8％时具有极大值；400℃活化处理可使Zn与Al-CLM之间具有适中的相互作用，从而使得Zn/Al-CLM具有较高的芳烃收率。     

合成2—芳氧基—5—氟—3H—4—嘧啶酮的新方法

由２－氰－５－氟－３Ｈ－４－嘧啶酮和取代苯酚钠在常压下反应，合成了７个未见文献报道的２－芳氧基－５－氟－３Ｈ－４－嘧啶酮化合物，产率７０￣８７％，结构经ＩＲ、＾１Ｈ ＮＭＲ和ＭＳ证实。     

Fe-Co-Ni合金纳米线有序阵列的模板合成与磁性

以二次阳极氧化的氧化铝膜为模板，用电化学沉积的方法成功地合成了Fe-Co-Ni三组份有序纳米线阵列.扫描电子显微镜（SEM）和透射电子显微镜(TEM)观察表明纳米线表面光滑、有序、高长径比；磁性测量表明,其矫顽力较同组份的膜材料有较大的提高.将样品在惰性气体氛围中不同温度下退火，随着退火温度增加，其纵向矫顽力有一个极值，而对应的横向矫顽力没有类似的变化，关于这一现象的机理,本文进行了初步的讨论. 图5参15     

Conversion of phenyl-substituted cyclopentadienes to pyrylium cations

Phenyl-substituted cyclopentadienes are proved to form phenylated pyrylium cations in the presence of silver(I) perchlorate by insertion of an oxygen atom into the cyclopentadiene-ring. Three phenylated pyrylium compounds, [(Ph(5)C(5)O(+))(ClO(4)(-))](2)(CH(2)Cl(2)) (1), Ag(ClO(4))(H(2)O)(Ph(4)HC(5)O(+)) (ClO(4)(-)) (2), and (Ph(3)H(2)C(5)O(+))(ClO(4)(-)) (3) have been synthesized and characterized. A possible reaction pathway and formation mechanism of the pyrylium cation are proposed and discussed.     

Coating Carbon Nanotubes with Europium Oxide

Carbon nanotubes (CNTS) coating with europium oxide by a simple method is reported in this letter for the first time. The CNTS were refluxed in a solution of nitric acid containing europium nitrate, and the pH value was subsequently ajusted with ammonia solution. At last, the mixture was filtered and annealed. The TEM micrograph showed that the CNTS were covered with a uniform thin layer with thickness of about 15 nm. The XRD results revealed that the CNTS were coated with europium oxide.     

Lithium dioxobis[trioxoiodato(V)]vanadate,Li[VO2(IO3)2]

The title compound represents a new structure type, in which distorted VO₆ octa­hedra are bridged by iodate groups to form infinite two‐dimensional [VO₂(IO₃)₂]⁻ layers that are separated by octa­hedrally coordinated Li⁺ cations.     

1,4-二乙氧基苯的相转移催化合成

采用大孔型交联聚苯乙烯为载体研究制得新型季Lin盐型相转移催化剂Y98B，并将其于1，4－二乙氧基苯的催化合成反应，进行了产品的红外光谱分析和熔点测定，探讨了催化剂用量、对苯二酚与溴乙烷物的质量比、反应温度和反应时间等动力学条件对产品收率的影响。确定了在反应温度为70℃,mol对苯二酚：mol溴乙烷＝1：3．5，反应时间4h，催化剂用量3．0g的条件下产品收率可达84.3%。     

关于氧化锌—二氧化硅表面结构和表面酸性的补充研究

我们管报道浸渍法制备的ZnO/SiO_2的表面酸性和表面结构。证明:(1) ZnO单层分散在硅胶表面,分散阔值为～0.22gZnO/100m~2SiO_2;(2) 样品表面出现了单独的ZnO与SiO_2所没有的较强酸位并且其酸量与ZnO表面浓度有很好的对应关系。由此提出了ZnO与SiO_2表面相互作用形成了某种酸性结构单元的观点。Sumiyoshi,Tanabe等曾报道,用共沉淀法制取的ZnO-SiO_2表面酸性显著。认为酸性的根源是ZnO与SiO_2间形成了田部(K.Tanabe)模型所预示的那种二氧化物,结构中     

A method of tracking ensembles of particle images

A method for tracking ensembles of particle images of a digital PIV record by making use of the minimum quadratic difference (MQD) technique is described. The similarity of this method with correlation schemes used for the evaluation of PIV is discussed. The method is exemplified with two applications that are also evaluated by auto- and cross-correlation, respectively.Receipt of a fellowship from Deutscher Akademischer Austauschdienst (DAAD) for L. C. Gui is gratefully acknowledged.