环己烯水合制备环己醇的研究 I．分子筛结构及晶粒大小的影响

考察了三种不同结构的分子筛（ZSM－5，MCM－22及-β）以及不同晶粒大小的ZSM－5分子筛对环己烯水合反应的催化活性。结果表明，具有12元环孔道体系的β分子筛对环己烯的转化率（9．6％）最高，但对环己醇的选择性（35．4％）最差。MCM－22分子筛的活性很低，其环己烯转化率只有0．8％。而孔口为10元环结构的ZSM－5分子筛则具有较高的活性环己烯转化率7．5％）和产物选择性（99．2％），因此是较好的水合催化剂。ZSM－5分子筛的晶粒大小对其环己烯水合反应活性有明显的影响，分子筛晶粒越细，则水合反应活性越高，其原因大于晶粒变细增大了分子筛的外比表面积，从而增加了接近孔口处的活性中心的数量。     

ZSM－5（核）／AlPO4－5（壳）双结构分子筛的合成与催化裂化性能

 采用X射线衍射、扫描电镜、X射线能量散射谱、红外光谱和核磁共振等多种物化方法对合成的ZSM－5（核）／AlPO4－5（壳）双结构分子筛进行了表征，证明这种材料具有以ZSM－5为核层、以AlPO4－5为壳层的双结构特征．考察了合成条件对ZSM－5（核）／AlPO4－5（壳）分子筛形貌的影响，发现ZSM－5分子筛的加入方式对产物的形貌有较大影响．重油裂化反应结果表明，ZSM－5（核）／AlPO4－5（壳）双结构分子筛的催化性能比ZSM－5和ZSM－5／AlPO4－5机械混合分子筛样品好，表现为原油转化率和低碳烯烃、汽油及柴油收率提高．     

晶化时间对ZSM-5分子筛物化性质及催化性能的影响

 考察了ZSM－5分子筛在晶化过程中的变化规律及其在苯与乙烯气相烷基化制乙苯反应中的催化性能．结果表明,当晶化时间为70h时,分子筛晶体开始出现;晶化90h时无定形物相基本消失．晶化时间从90h再延长至150h,ZSM－5分子筛晶粒的大小、形貌和体相硅铝比都基本不变,但分子筛表面的硅铝比逐渐降低．以晶化时间为90h的ZSM－5分子筛原粉为活性组元制备的催化剂,对苯与乙烯气相烷基化制乙苯反应表现出最佳的催化性能．     

不同晶粒大小ZSM－5的合成和表征

采用水热合成法，由不同途径合成出晶粒大小不同的几种ＺＳＭ－５分子筛，这几种分子筛具有大致相同的硅铝比．采用ＮＨ３－ＴＧ－ＴＰＤ，Ｐｙｒｉｄｉｎｅ－ＩＲ－ＴＰＤ表征其酸性，用ＸＰＳ表征其外表面的硅铝比（体相的硅铝比用元素原子吸收法测定）．研究结果表明，应用导向剂可以合成出要求的晶粒大小而且粒度均匀；加晶种的合成得不到较大的晶体，粒度亦不均匀．分子筛的晶粒大小对其酸性有一定的影响，一般来讲，小晶粒分子筛的酸量多．本文中大晶粒分子筛的硅铝比基本上是不均匀的．     

大晶粒ZSM-5分子筛的合成及其催化性能的研究

ZSM-5分子筛对许多正碳离于反应有优异的择形催化性能。近年来的研究表明,ZSM-5沸石的晶粒大小对其催化活性、选择性和稳定性有显著影响。如对甲苯歧化、甲苯与甲醇的甲基化反应,大晶粒ZSM-5分子筛对生成对二甲苯有较高的选择性。对于二甲笨液相异构化反应,小晶粒ZSM-5沸石具有较高的催化活性和选择性。我们用“直接法”合成了大晶粒(34×116μ)ZSM-5沸石分子筛,比较了不同晶粒大小ZSM-5分子筛催化剂在一些反应中的催化性能。大晶粒ZSM-5分子筛系不用有机胺,直接用水玻璃、硫酸铝、硫酸为原料合成的。用光学显微镜、扫描电镜观察所得分子筛的晶粒外形和大小,取5—6个有代表性的晶粒计算其平均尺寸。用BET重量法测定分子筛对正己烷、环己烷和水的吸附量。用X—射线衍射分析样品的物相。在160—200℃温度范围内考察了晶化温度对晶粒大小的影响,所得结果如表1。     

晶粒大小对ZSM-5分子筛甲醇制低碳烯烃催化性能的影响

对三种HZSM-5分子筛进行Ca改性,获得两组酸性接近的催化剂,考察了晶粒大小对甲醇制低碳烯烃(MTO)反应的影响。通过进一步与Na改性的比较,探讨了Ca在催化反应中的作用。采用扫描电镜(SEM)测定晶粒大小及形貌,氨气程序升温脱附(NH3-TPD)及吡啶红外吸附(Py-IR)表征催化剂的酸性。MTO催化性能测定结果表明,HZSM-5的低碳烯烃选择性较低且下降较快,催化活性降低也快;Ca改性降低酸性,提高了低碳烯烃选择性和催化稳定性;晶粒大小主要影响催化稳定性,小晶粒分子筛催化剂稳定性更好。高Ca含量改性效果更好;钠改性也提高了低碳烯烃选择性,但其稳定性较差。对于HZSM-5和Ca/HZSM-5,小晶粒的催化剂具有较好的催化稳定性。提出Ca参与了催化反应,MTO是一个酸碱协同作用的催化过程。     

以环己胺为模板剂的ZSM－35分子筛的合成及其催化性能

 采用环己胺为有机模板剂成功地合成出ZSM－35分子筛．反应釜的转速对ZSM－35的晶化过程有明显的影响．NH3－TPD结果显示ZSM－35的酸性分布与ZSM－5分子筛类似，但ZSM－35具有强于ZSM－5的酸性中心．酸碱浸泡试验及热分析结果表明ZSM－35具有良好的耐酸碱性和热稳定性．在连续流动的固定床反应装置上，将担载少量镍的ZSM－35分子筛催化剂用于催化裂化汽油的加氢异构化反应，结果表明，Ni／ZSM－35催化剂可降低汽油中的烯烃含量，增加异构烷烃和芳烃的含量，从而提高汽油的质量．     

晶种存在形态对所合成的SAPO-34分子筛性质及其甲醇转化催化性能的影响

采用常规水热合成法、添加粉末晶种和添加含有分子筛前驱体的液相晶种等方法制备了低硅铝比的SAPO-34分子筛。采用XRD、SEM、FT-IR及TPD等表征手段研究了合成方法对晶体结构、形貌、晶粒粒径及酸性的影响。并在固定床上对比了其甲醇转化制烯烃的催化性能差异。结果表明,晶种存在形态对分子筛的结晶度影响不大,但影响了硅在骨架中的分布、晶粒粒径和酸性等。与添加粉末晶种相比,采用含有分子筛前驱体的液相晶种法更有利于减小分子筛晶粒粒径,降低分子筛酸性,提高低碳烯烃选择性。     

高硅分子筛ZSM-22的动态合成及表征

 以1，6－己二胺（DAH）为模板剂，采用水热条件下的动态合成方法，合成出结晶度良好的ZSM－22晶体．研究表明，合成的关键是避免ZSM－5分子筛的生长，当n（Si）／n（Al）＝25～65，n（H2O）／n（SiO2）＝16．3～40．3，n（DAH）／n（Si）＝0．1～0．6和T＝428～448K时，都能稳定合成出ZSM－22分子筛．采用TEM，XRD，TG－DTA和NH3－TPD等方法，对ZSM－22晶体的形貌，生长动力学，模板剂的作用以及硅铝比对分子筛酸性的影响等进行了较详细的研究．实验结果和理论计算证实，1，6－己二胺分子以首尾相连的方式，线性排列并完全充满ZSM－22的十元环孔道，同时起到结构导向和骨架电荷平衡的作用．     

小晶粒A型分子筛的合成及其晶貌

分子筛晶粒的大小对分子筛的催化、吸附及离子交换性能均具有很大的影响．以常规方法合成的Ａ型分子筛，其晶粒大小一般分布在１～１０μｍ，平均粒径大于２μｍ，并且样品中含有３％～１２％超过４５μｍ的大晶粒［１］．在合成过程中，凝胶混合物的配比、成胶和晶化条件...     

多环芳二酐型聚酯亚胺膜的透气性能

多环芳二酐型聚酯亚胺膜的透气性能李悦生，丁孟贤，徐纪平（浙江大学高分子科学与工程研究所，杭州，３１００２７）（中国科学院长春应用化学研究所）关键词聚醚酰亚胺，聚酯酰亚胺，膜，透气性通常的聚酰亚胺加工性能较差，在芳环二酐的苯环间引入醚键等柔性基团后，其...     

Determination and study on residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil

A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg^?1, the maximum residue level of European Union for quizalofop-p-ethyl).     

微量元素与疾病诊断治疗的研究现状及展望

对国内外微量元素与疾病的关系及其诊断治疗的研究现状及研究动向进行了综述，包括：微量元素与地方病、癌肿、心血管病、糖尿病、眼病、神经系统病等。参考文献72篇。     

Conformations and steric and stacking interactions of trisubstituted ureas and thioureas with alkyl and phenyl groups

The monomeric ν(N—H) vibrations of various trisubstituted ureas of the R₂UPh type and -thioureas of the R₂TUPh type have been studied. The trans—out isomerism in the former and the trans—out—cis isomerism in the latter are discussed from the point of view of steric effect. The monomeric ν(N—H) vibrations of RPhUPh and RPhTUPh are also examined. The single band appearing in the spectrum of both ureas is characteristic of the cis form; this suggests the existence of phenyl—phenyl interaction (the stacking interaction proposed by Galabov et al. [10]). Behavior of ν(N—H) vibrations at several concentrations is shown to be clearly different in the three forms (trans, out and cis). The presence of the cis form is confirmed by solvent effect experiments.     

Ti-V基储氢合金及其氢化物的物相结构与组分优化设计

Ti-V基储氢合金在室温、常压下即可表现出良好的储氢特性,且质量储氢容量明显高于传统AB₅型储氢合金,从而在氢气的精制和回收、运输和储存及热泵等方面有较早的应用。 此外,在混合气体分离、核反应堆中处理氢的同位素、镍氢电池及燃料电池负极材料等方面也得到了广泛的研究与关注。 基于目前Ti-V基储氢合金的研究现状,概述了该类合金的优势、限制性因素(包括成因)及改性手段。 此外,为了进一步理解Ti-V基合金储氢机理、构建合金组分与储氢特性之间的对应关系,本工作重点围绕Ti-V基储氢合金及其氢化物的结构、组分优化设计展开综述,并对其未来研究方向做出展望。     

钒与糖代谢及糖尿病

微量元素钒作为生物体内必需元素，经证实有很重要的生理学功能，与机体糖代谢有十分密切的关系，且能降低糖尿病动物模型的高血糖，极有可能被开发为治疗糖尿病的药物。     

Ferrocene and ferrocenium modified clays and their styrene and EVA composites

In this work, ferrocene- and ferrocenium-containing salts were employed to modify montmorillonite. X-ray measurements show an increase in the interlayer spacing upon clay modification, which means that the larger and more organophilic cations were inserted into the gallery space of montmorillonite. Attempts to prepare nanocomposites of polystyrene and ethylene vinyl acetate copolymers lead to immiscible systems; the morphology of these systems was elucidated with TEM, XRD and cone calorimetry. The thermal stability of the composites is greater than that of the virgin polymer.     

Synthesis and Optical and Redox Properties of Symmetric and Asymmetric BODIPYs

Herein, we present the synthetic route and the photophysical, electrochemical as well as laser properties of novel red‐emitting boron‐dipyrromethenes (BODIPYs) bearing arylethyne moieties. Such functionality is added along the main axis of the chromophore leading to single‐ and double‐substituted derivatives. The relationship between the dye structure and the lasing properties is studied in detail with the help of the photophysical and electrochemical properties as well as quantum mechanical simulations. The asymmetric substitution of the parent dye induces inhomogeneities in the charge distribution, which leads to an overall loss of the fluorescence capacity, mainly in polar media. Such non‐radiative deactivation processes can be softened by decreasing the electron‐donor ability of the substituent or even avoided by symmetrical substitution. Thus, grafting of the arylethyne moieties at the longitudinal axis of the indacene core results in an effective strategy to develop red‐edge BODIPYs with highly efficient and photostable laser emission.     

Synthesis of Tyrosol and Hydroxytyrosol Glycofuranosides and Their Biochemical and Biological Activities in Cell-Free and Cellular Assays

Tyrosol (T) and hydroxytyrosol (HOT) and their glycosides are promising candidates for applications in functional food products or in complementary therapy. A series of phenylethanoid glycofuranosides (PEGFs) were synthesized to compare some of their biochemical and biological activities with T and HOT. The optimization of glycosylation promoted by environmentally benign basic zinc carbonate was performed to prepare HOT α-L-arabino-, β-D-apio-, and β-D-ribofuranosides. T and HOT β-D-fructofuranosides, prepared by enzymatic transfructosylation of T and HOT, were also included in the comparative study. The antioxidant capacity and DNA-protective potential of T, HOT, and PEGFs on plasmid DNA were determined using cell-free assays. The DNA-damaging potential of the studied compounds for human hepatoma HepG2 cells and their DNA-protective potential on HepG2 cells against hydrogen peroxide were evaluated using the comet assay. Experiments revealed a spectrum of different activities of the studied compounds. HOT and HOT β-D-fructofuranoside appear to be the best-performing scavengers and protectants of plasmid DNA and HepG2 cells. T and T β-D-fructofuranoside display almost zero or low scavenging/antioxidant activity and protective effects on plasmid DNA or HepG2 cells. The results imply that especially HOT β-D-fructofuranoside and β-D-apiofuranoside could be considered as prospective molecules for the subsequent design of supplements with potential in food and health protection.